DX Imaging 1 MT and Final

8/17/2019 DX Imaging 1 MT and Final

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Diagnostic Imaging I Class Notes Page 1 of 24

TYPES OF DIAGNOSTIC IMAGING:

1.Plain x-ray

2. MRI - premier imaging for soft tissues.

3. Fluoroscopy

4. CT

5. PET - positron emission

6. SPECT- single positron emission7. Nuclear imaging (ex: bone scanning)

8. Ultrasound (ex: echocardiogram used for the heart)

9. Contrast studies (another specialized use of x-rays)

CHEST

DIAGNOSTIC IMAGING OF THE CHEST:

1. Plain films (no contrast, special techniques, or equipment)

a. Routine chest series

1. P-A chest view/P-A teleoroentgenogram (inspiratory)

Structures seen:

a. Aortic arch

b. Pulmonary trunk

c. Left atrial appendage

d. Left ventricle

e. Right atrium

f. Superior vena cava

g. Diaphragms

h. Horizontal fissure

Imaging on Inspiration: should see 10 posterior ribs and 6 anterior ribs)

Chest x-rays are usually taken at high KVP’ s (around 100)

2. Left lat. chest view

-to differentiate a left lat. chest view from a lateral spine view is determined by where thehumerus is (in left lat. chest view, their arms will be up over their head)

a. Oblique fissure

b. Horizontal fissure

c. Thoracic spine

d. Retro sternal space

b. Special (non-routine) view

1. Apical- lordotic view

2. MRI

-Evaluation of hilar and other mediastinal masses, peripheral nodules, and vascular lesions may be done

effectively-No ionizing radiation exposure

3. Nuclear imaging

- Effectively assesses the presence of pulmonary emboli. It is mainly used to assess blood flow and ventilation

4. Bronchoscopy

- Fiber-optic camera is used to view the tracheobronchial tree. Cell samples may be obtained thought the scope

for further evaluation. Needle biopsy may also be performed using the scope.


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5. Diagnostic Ultrasound (Sonography)

-Used extensively in cardiac, GI & GU imaging.

-Lung sonography may be used to detect pleural fluid.

-Sonography of the musculo-skeletal system is developing

-Differentiate therapeutic ultrasound from diagnostic ultrasound

6. Echocardiography (=heart sonography)-used in imaging the anatomy and the functioning (to some extent) of the heart and pericardium.

7. Doppler ultrasound

- Used to measure the rate & volume of blood flow

8. Angiography

-Examination of vascular structures by injecting water soluble agents either transcutaneous y, via surgical

incision or catheterization.

-The course of the contrast agent is followed by a rapid sequence of x-ray exposure

-The images may also be digitized and the other structures can be digitally erased (Digital subtraction

angiography)

-Function can also be examined fluoroscopically.

-CT can be added for more detailed examination.

9. Fluoroscopy

-Useful in studying structures in motion such as the diaphragm and heart. Helpful in demonstrating a

mediastinal shift.

10. Tomography/laminography

- It is somewhat out-dated by the development of CT

- Can be used to demonstrate: calcifications within a lesion or nodule, presence or absence of cavitation within

a lesion, and obstructions with the bronchial tree.

11. Bronchography

- A contrast exam of the tracheobronchial tree. Outdated by use of bronchoscopy.

INTERPRETATION OF CHEST RADIOGRAPHS

Types of pathologies visible on chest radiographs

- Lung pathologies

- Cardiovascular paths.

- Extrapleural paths

- Mediastinal paths

- Abdominal paths

Health risk is minimal Observe the following:

-Trachea - look for air shadow in the midline with the tracheal bifurcation (carina) at the level of T4/5

intervertebral disc

-Mediastinum - the extrapleural space between the lungs marks the mid region of the thorax. It consists of the

heart, pericardium, great vessels, trachea, thoracic duct, thymus, fat, nerves, numerous small vessels, lymph

nodes, and lymphatic vessels.

a. Anatomic mediastinum is divided into 1. Anterior 2. Middle, 3. Posterior, and 4. Superior segments

b. Radiologic mediastinum is divided into 1. Anterior mediastinum, 2. Mediastinum, and 3 posterior

mediastinum


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Diagnostic Imaging I Class Notes Page 3 of 24-Heart and Great Vessels (see chapter 4 in Daffner's text)

-Lungs- density, size and shape, branches of pulmonary arteries and veins. On PA view they go below the level

of the diaphragm

-Pleura - Normally, only the fissures are visible.

-Costophrenic angles (and cardiophrenic angles)

-Diaphragms - right hemidiaphragm is normally higher than the left

-Bones and soft tissues - muscles, sternum, ribs, cervical and thoracic vertebrae, clavicles, scapulae, etc.

Normal anatomical variants as seen on P-A chest view

1. Idiopathic costochondral calcinosis -Calcification of the costal cartilages is seen due to the soft metallic density

of the calcium deposits. Insignificant except that the opacity of the calcium is commonly misinterpreted as a

mass. Thusly, AKA the great mimicker of pathology.

2. Calcification of the cartilaginous rings of the trachea- Distinctive equidistant bands of opacification may be

seen superimposing the lucency of the tracheal air shadow, or bordering it. Insignificant

3. Cervical ribs and hypertrophic C7 T.P's. - these congenital anomalies may cause a cervical rib/thoracic outlet

syndrome in some patients.

4. Scalloping of the Diaphragm- (single or multiple) localized superior bulging of part of the dome of the

hemidiaphragm -- Insignificant.

5. Pectus Excavatum/Funnel chest - Congenital invagination of inferior aspect of the sternum. Manifested on

P-A chest views by loss of right heart shadow lateral to the sternum.

6. Dextra cardia - Congenital anomaly in which the heart is right sided. Often there are additional congenital

heart anomalies

Basic patterns of Lung Pathologies

1. Consolidation

2. Atelectasis

3. Pleural Effusions and other pleural pathology

4. Masses

5. Emphysema

6. Infiltrates

1. Consolidation: AKA air space disease

- Def.: abnormal opacity in the lung due to replacement of air in the alveoli by fluids or cells (or tumors) such as

blood, inflammatory exudates, edema, or aspirated fluid.

-Classically homogeneous (uniform)

-Common causes of consolidation include lobar or segmental pneumonia.

-Radiographic signs of consolidation:

-Air bronchogram signs indicates pulmonary pathology and helps exclude pleural or mediastinal

pathology. Air in the bronchi becomes visible when the adjacent alveoli of the lung become filled with

fluids or cells. Air bronchogram is the most reliable method of seeing consolidation.

-Silhouette signs = loss of visualization of the border formed between the consolidation and the heart,aorta, or diaphragm if the lesion in the lung is contiguous with the border of the structure

-Normal lung volume (helps distinguish from atelectasis, where the volume appears decreased)

-Lack of visualization of pulmonary vessels.


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The Silhouette sign

- Description= loss of visualization of the border formed between a lung pathology and the heart, aorta, or other

water density structure if the pathology is contiguous with the border of the structure.

-Helpful in locating the abnormality

-If the overlap between the pathology and the normal anatomy is clearly visible, the pathology is not in physical

contact with the structure, but its opacity is only superimposed onto the structure because of the plane of the

x-ray beam. The pathology is anterior or posterior to the structure.- Example: when you look at a lateral x-ray, the left lung produces a silhouette sign (with the heart) where the

right lung does not.

- Example of the use of the silhouette sign: If pathology obliterates the left heart border, a POSITIVE SIGN, i

must be located anteriorly (location of heart). Therefore, the pathology is probably located in which segment of

the left lung? (Lingula) (See ch. 4 in Felson's Principles of Chest Roentgenology) or see table 4.1 in the textbook

(Daffner). Review for anatomy of lung and aorta (WILL BE ON MIDTERM)

- A silhouette sign just helps you to locate pathology, it doesn't tell you what the pathology is.

Cervicothoracic sign

-This is a variation of the silhouette sign used when there is pathology with a positive silhouette sign at the

upper mediastinum (on a PA view). If the pathology disappears above the clavicle (positive sign), it is in contact

with the water density tissues of the neck (in the anterior mediastinum).

-If it continues above the clavicle (If the entire lesion is visible), it's intrathoracic, in the apical region.

Pneumonia

- An inflammatory reaction in the lungs, occurs either as a primary infection of the lungs, or secondary to

bronchial obstruction.

2. Atelectasis

- Def: loss of volume in part or the entire lung.

- Radiographic signs:

1. Direct signs: deviation of a fissure is the most reliable sign that indicates compensatory hyperinflationof the lobe adjacent to the collapsed lung. Other direct signs include increased opacity, crowded vessels

and the presence of a silhouette sign.

2. Indirect signs: Displacement of hilar vessels toward the lesion is the most reliable sign. Shift of the

mediastinum, elevation of hemidiaphragm, compensatory emphysema, herniation of the lung across the

midline, and approximation of the ribs may also be present.

- Different types of atelectasis

1. Obstructive (resorptive): It is the most common type. Neoplasm, foreign body, mucous plug, or

inflammatory debris obstructs airway. It is often associated with pneumonia distal to the obstruction

site. There is no new air coming in and collapses the lung.

2. Compressive - Tumor, emphysematous bulla (a large collection of dead air), pleural effusion, or

enlarged heart physically compress the lung.3. Cicatrization - It is caused by contraction of organizing scar tissue and is often associated with healing

tuberculosis, granulomatous diseases, pulmonary infarct, and pulmonary trauma.

4. Adhesive - Airway is patent (airway is coming in to lungs); however, surfactant is inactivated. (Hyaline

membrane disease)

5. Passive - Airway is patent. Lung compliance is normal but the normal negative pleural cavity vacuum

is lost due to pneumothorax or hydrothorax and the lung deflates like a balloon.

- Right upper lobe collapse: There is increased opacity in the right upper zone. As collapse progresses the fissure

moves and bows upwards. RUL collapse is less visible on the lateral film.


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Diagnostic Imaging I Class Notes Page 5 of 24- Right lower collapse: R lower zone shadowing is combined with obliteration of the hemidiaphragm (silhouette

sign)

- Right Middle lobe collapse: Ill defined shadowing is evident adjacent to the right heart border, which becomes

indistinct. Wedge shaped opacity on the lateral film, which superimposes the heart shadow. The apex of the

wedge is anterior to the main airway.

- Left upper lobe: The lung collapses anteriorly. It thus presents no sharp margins on the frontal film. On lateraview, there is a major shift of the major fissure toward the anterior.

- Left Lower lobe: Collapses medially and posteriorly to lie behind the heart. Displays a triangular opacity.

- Total collapse: Occurs due to obstruction within the main stem bronchus.

3. Pulmonary edema:

- Descriptions: the accumulation of fluid in the interstitium and/or alveoli due to either:

1. Increased capillary pressure

2. Increased capillary permeability, or

3. Impaired venous or lymphatic drainage.

-Radiologists usually attempt to distinguish interstitial from alveolar edema, but one often leads to the other

and assessment is quite subjective

-The context for evaluating edema is usually provided by history and exam findings.

-Edema may be caused by infection, trauma, allergy, drugs, toxins (including those from metabolic disorders), as

well as cardiovascular diseases.

X-ray signs:

- Edema with cardiomegaly is usually caused by cardiac disorders, such as congestive heart failure

-Edema is usually seen as a non-homogeneous opacification of the lungs and is usually bilateral, however, when

unilateral it usually indicates infection or trauma.

-When alveolar edema produces a homogeneous opacification it is called consolidation. The boundary is very

subjective.-Interstitial edema, if chronic, often leads to interstitial fibrosis. This distinction is also often subjective

radiographically.

-Bilateral edema may be caused by a large variety of conditions. Lab cases include: infections, near drowning,

drug overdose, eosinophilia and others.

X-ray signs of alveolar/acinar edema:

-Hili are indistinct and opacification is greatest centrally -- batwing or butterfly pattern.

-Fluffy margins

-Coalescence into consolidation

-Rapid change

-Air bronchograms.

X-ray signs of interstitial edema

-Combinations of linear and nodular opacities

-"Reticular" (web-like), "reticulonodular"

-Honeycomb lung is a specific term for end-stage interstitial fibrosis

-Slower to change

-Septal (AKA Kerley) lines


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Kerley/septal Lines

-Description: a sign of interstitial edema due to edematous interlobular septa (interstitial) represented by thin,

non-branching linear densities:

a. Kerley A lines - upper lungs (a=apical) oblique, directed toward the hilum

b. Kerley B lines - transverse, seen near the lung bases at the periphery near the costophrenic angles.

Pulmonary Tuberculosis:-Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis primarily affecting the respiratory

tract, but TB can affect any body system. The incidence of TB has been on the rise.

-TB can be primary or secondary.

1. Primary TB

-Represents the initial infection

-Most cases, the patients are asymptomatic: however, the course of initial infection is highly

variable. Infants, young children, and immunodeficient adults are at risk.

-X-rays are usually normal, however, they may show interstitial edema or a small area of

consolidation (AKA the Ghon focus). Usually this heals to form a granuloma.

-Hilar lymph nodes are often enlarged on the affected side.

-Healing process may calcify both the hilar nodes and the Ghon focus (lesion) producing the

Primary/Ranke Complex.

2. Secondary TB ( AKA: Reactivation TB)

-Reactivation of primary (often subclinical) infection is usually chronic and severe due to

hypersensitivity acquired from the primary infection.

-Lung apices are most commonly infected. X-rays demonstrate patchy consolidation, which may

form a mass with or without cavitation.

-Solitary or multiple nodules may appear.

-Fibrosis, cicatrization (fibrocystic) atelectasis, cavities and calcifications often result.

- Miliary TB

-An uncommon but radiographically distinctive pattern of TB, caused by hematologic dissemination ofthe infection, producing multitudinous, small (1-2 mm), discrete pulmonary nodules bilaterally.

-Clinically, patients are very ill and may die, but with adequate treatment, complete resolution is likely.

4. Masses and Nodules

* Masses - greater than 3 cm

* Nodules - smaller than 3 cm

If solitary:

- Masses:

a. Lung cancerb. Round pneumonia

c. Large Solitary Metastases

d. Lung Abscess

- Nodules:

a. Granuloma (especially if calcified)

b. Lung cancer

c. Benign lung tumors

d. Metastasis

e. Rounded atelectasis

f. Septic embolism


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If Multiple:

- Masses:

a. Metastases

b. Granulomas

c. Primary malignancies

- Nodules:

a. Granulomas

b. Metastasesc. Septic emboli

*Note: The first step is to rule out an extrapulmonary shadow from a skin lesion, nipples, rib fracture, etc.

Characteristics of Benign and Malignant Lesions

Malignant lesions:

-Larger than 3cm AKA masses

-Irregular shape

-Spiculated margins

-Significant growth of lesion in the last two years-No calcification

-May cavitate

- (Inverted) S sign of Golden (see below)

Benign Lesions

-Smaller than 3cm AKA nodules

-Regular shaped (round)

-Smooth margins (well defined edges)

-No growth (no significant change in the last two years) - IMPORTANT CLUE

-Calcification (especially if central, laminated, or "popcorn ball")

-Solid (no cavitation)

Golden's S sign (a backward S):

When there is a bulge at the lower margin of the collapsed upper lobe. This is due to right hilar

carcinoma. The minor fissure wraps around the mass as the fissure moves from horizontal to angled (as

it would with a collapsing lung).

Common causes of cavitated lesions /masses

-Lung carcinoma (usually squamous cell cancer)

-Abscesses

-Hematomas

-Granulomas caused by:

1. TB2. Fungal infection

- a fluid level in a mass is pathognomonic of cavitation

Types of Lung Cancer:

- Bronchogenic carcinoma- Patients often complain of coughs, weight loss, chest pain, and dyspnea. History of

smoking. Age greater than 40, occupational hazards, etc.

1. Squamous cell carcinoma (epidermoid)

2. Adenocarcinoma (acinar, papillary, bronchioloalveolar)

3. Small cell carcinoma (oat cell, intermediate cell)

4. Large cell carcinoma (giant cell, clear cell)


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- Pancoast Tumor AKA Superior sulcus tumor

-Bronchogenic carcinoma in the lung apices. Most commonly, a squamous cell carcinoma.

-X-ray appearance is usually a dense, homogeneous mass, with a defined border, in the apex, with signs

of invasiveness:

a. Upper rib and vertebral destruction is common and may be seen on spine x-rays.

b. Pleural invasion may produce effusion

-Cervical sympathetic plexus invasion to produce severe pain and may cause Horner's Syndrome(enophthalmos, ptosis, miosis, and anhidrosis)

Other Pleural space conditions:

-Pleural effusion

-Pleural fibrosis

-Extrapleural lesions

-Pleural Tumors

-Pneumothorax

Cardiac Failure: Congestive Heart Failure

-Descriptions CHF results when the oxygen supply to the body tissues is inadequate due to impeded functioning

of the heart. This usually caused by lowered cardiac output from ischemic heart disease.


-Enlarged cardiothoracic ratio/cardiomegaly

-Cephalization of blood flow = increased vascular markings in the upper lungs with decreased markings

in the lower lungs. Only done if pt. is not bedridden.

-Pleural effusions: free, subpulmonic or loculated (vanishing tumors) & thickened fissures

-Signs of pulmonary edema: both interstitial (septal/ Kerley lines), and in later stages, alveolar (bat-wing

or butterfly pattern)

Sarcoidosis (AKA Boeck Disease, Benign Lymphogranulomatosis)

- Def: generalized epithelioid cell granulomatosis, frequently involves intrathoracic lymph nodes and the

pulmonary parenchyma, most patients with sarcoidosis have immunologic abnormalities. - Radiological findings:

- Stage 1 (Intrathoracic Adenopathy): bilateral or unilateral lymphadenopathy, mediastinal lymph node

enlargement. "Potato Nodes".

-Stage 2 (Miliary Stage): pulmonary granuloma enlargement, interstitial pattern

-Stage 3 (Pulmonary fibrosis): linear opacities radiating from the hila into the lung accompanied by

coarse reticular markings and honeycomb pattern

-The "1,2,3" sign: Potato nodes, bilateral hilar node enlargement, and lymphadenopathy in the right tracheal

area.

Extrapleural Sign

- Def: Radiographic appearance of lesions that displace the pleura from the outside.-Rib lesions such as tumors and fractures are the most common cause.

-Extrapleural sign is present when an opaque mass with a smooth, sharply defined convex border appears at the

lung periphery or the mediastinum. The tapering border of the mass forms an obtuse angle with the chest wall

or mediastinum.

-Pleural effusions are not usually associated with extrapleural lesions.

Pleural Fibrosis

-Fibrosis is a permanent thickening and opacification of the pleura. It may be seen at the periphery of the lung

or within a fissure. Usually a sign of previous inflammation. Slight apical fibrosis is often idiopathic in older

patients (Apical Capping) or seen more extensively in post-secondary TB.


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Asbestos Exposure/Asbestosis

Radiological Appearance:

-Focal pleural plaques adjacent to ribs (often the earliest finding)

-Calcified pleural plaques (bilateral diaphragmatic calcifications are highly suggestive of previous asbestos

exposure)

-Diffuse pleural thickening

-Pleural effusions-Pulmonary fibrosis

-Malignant disease such as mesothelioma, bronchial carcinoma, and laryngeal carcinoma.

Pleural Tumors

-Pleural Tumors are uncommon although lymphoma can occur here.

-Mesothelioma may occur in patients exposed to asbestos.

-Pancoast Tumors often invade the pleural space, however, they are primarily in the lung.

4. Emphysema

- Def: Permanent enlargement of airspaces distal to the terminal bronchiole accompanied by destruction of

parenchyma but without obvious fibrosis.

-Emphysema is commonly associated with chronic obstructive pulmonary disease/ COPD.

-Diagnosis of COPD should be based upon physical findings as x-ray findings may be lacking.


-Signs of hyperinflation: hyperlucency, increased retrosternal clear space, lowering or flattening of the

diaphragm, , saber sheath trachea, and narrow, vertically elongated cardiac configuration

-Signs of vascular changes: Decreased vascularity/oligemia is reported to be the most reliable sign.

Acute tapering of peripheral vessels may also occur > "marker vessels"

-Bullae - cystic collections of dead air space

Pulmonary Emboli & Infarction

-Description: a detached blood clot(s) lodges in the pulmonary artery or its branches resulting in pulmonary

infarction-Types of Embolism:

a. Deep vein thrombus - usually from leg veins

b. Fat embolism - usually seen after severe skeletal trauma

c. Septic embolism - often results from tricuspid (bacterial) endocarditis.

d. Amniotic fluid embolism - most common cause of postpartum maternal death

Pulmonary Embolus Imaging 1

-Radiological findings: non-specific and may be lacking. Possible findings include:

1. Localized consolidation or infiltration, which may consolidate into a mass, which over time shrinks,

maintaining its original shape, "Melting Ice Cube Appearance"

2. X-ray is often normal3. Nuclear imaging is the best way to determine (radioisotopes)

Pulmonary embolus Imaging 2

-Nuclear imaging is useful

-Perfusion scans demonstrate lack of blood flow

-Ventilation scans demonstrate normal airflow

-Comparison used to calculate a V/Q ratio

-Other conditions can cause V/Q abnormalities, but if the x-ray is WNL this is evidence of embolism

-Pulmonary Arteriography, only when needed.


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Abdominal Conditions

-Chest x-rays include the upper abdomen in the field of view and abdominal conditions may be seen

-Pneumoperitoneum=free air in the peritoneal cavity.

PA CXR is often used for detection.

-Diaphragmatic Hernias (Hiatal and other)

-Calcifications

-Hepatomegaly

Hiatal Hernia:

- Description: a portion of the stomach is displaced through the esophageal hiatus of the diaphragm into the

thorax

- Types:

1. Sliding/Axial (95%) Very common, very dynamic, esophageal-gastric junction herniates intermittently

2. Paraesophageal - the esophageal-gastric junction remains below the diaphragm, but a portion of the

gastric fundus herniates into the chest next to the lower esophagus.

- Radiographic Findings: the magenblase superimposes the cardiac shadow in frontal views, appearing as a

hemispheric "black hole" in the heart with a horizontal lower border (air-fluid level). On lateral views the

magenblase is usually posterior to the cardiac shadow but may partially superimpose it.

END OF 1ST MIDTERM MATERIAL


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Diagnostic Imaging I Class Notes Page 11 of 24ABDOMEN

Evaluation of the abdomen: Types of Imaging Modalities

-Plain radiographs

-Contrast Media studies

-Angiography

-Ultrasonography (Diagnostic Ultrasound) *

-Computed Tomography (CT)-Nuclear Medicine & MRI

-Fiber Optics *

*commonly used for abdomen

Plain radiography of the abdomen

1. Routine views

a. Scout film (AP recumbent) = plain abdominal film

-old terms: KUB, flat plate

2. Additional views

a. A-P Upright film (AP lumbopelvic is virtually identical)

b. P-A Chest

c. Lateral

d. Oblique

e. Decubitus

Plain Radiography of the Abdomen

-AP Abdomen (Scout film, KUB)

-high kV technique is used to produce more shades of gray (80-100kV)

-the film is taken on full expiration (this allows elevation of the diphragm)

-the view should include the pubic symphysis

-usually done recumbent (reduces patient thickness and motion resulting better anatomic detail)

-A-P Upright Film-demonstrates air/fluid levels and free air in the peritoneal space

-the view must include the diaphragm

-P-A Chest Film

-also sensitive for pneumoperitoneum

-general screen prior to hospital admission

-Lateral Film

-a routine view for the lumbar spine

-helpful in locating the intra-abdominal structures (anterior, middle, or posterior)

-best view for detecting aortic aneurysms and calcified aortic plaques

-Oblique View

-helpful in localizing abnormal densities

-helps differentiate kidney stones from gall stones

-body is rotated 45 deg.

-Decubitus View

-usually left side of the body is in downward (this allows free air to raise above the liver)

-demonstrates gastrointestinal air/fluid level


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Diagnostic Imaging I Class Notes Page 12 of 24-Abdominal Imaging- structures to be evaluated:

a. lumbar spine

b. abdominal Aorta

c. abdominal organs (liver, spleen, kidneys, maybe bladder)

d. gas patterns (distension, displacement, or air/fluid levels)

e. calcifications

f. muscles (psoas especially), tendons

- Visible Soft Tissues in the Abdomen: the following organs are visualized on a normal abdomen film as water density

outlined by oil/fat density:

a. kidneys

b. spleen

c. liver

d. bladder

e. psoas muscles

f. flank stripes/properitoneal fat

-Patient size, motion, superimposed gas or fecal matter, presence of fluid (blood, pus, etc), or congenital agenesis may

obscure with visualizing the above structures.

- Location of abdominal structures

-Two perpendicular lines may be drawn through the navel Usually at the L3-L4 body) to divide the abdomen in

4 quadrants: RUQ, LUQ, RLQ, LLQ

-RUQ contains liver, gall bladder (although invisible normally) right kidney, part of right psoas muscle, & hepatic

flexure of the colon

-LUQ contains spleen, left kidney, part of left psoas muscle, & splenic flexure of the colon

-RLQ contains part of right psoas muscle, cecum, and part of bladder

-LLQ contains part of bladder, and sigmoid colon (which often crosses the midline into the RLQ), left psoas

muscle

- Body types:

-Hypersthenic - short-broad thorax and abdomen, organs appear more transverse and highly placed- Asthenic - very narrow thorax and abdomen, organs hang very low and are place mostly in the pelvic region

-Sthenic - normal body type, textbook appearance

-Hyposthenic - lanky type, organs appear longer and lower

* Sthenic (48%) and hyposthenic (35%) are most common types

Plain Film abdominal Soft Tissue Abnormalities

-Calcifications

-Post-surgical residuals

-Abnormal gas & mucosal patterns

-Abnormalities of the organs

-Ascites - rare-Pneumoperitoneum - rare

Abdominal calcifications: Terms that typically refer to soft tissues

conduits- tubular. can be linear or curvilinear

punctate (stippled) - small and scattered

granular - sand-like, fine punctate types

clumped =flocculent - stippled calcifications that coalesce

ringed (rimmed) - denser at the periphery (or lucent centrally)

laminated - concentric rings

irregular - varying densities/Non-homogeneous


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Diagnostic Imaging I Class Notes Page 13 of 24cloudy (hazy) - ill defined density

homogeneously dense - same density throughout

Abdominal calcifications: Terms used to define the shape & border of a calcification:

1. smooth

2. indistinct or ill-defined

3. well-defined

4. round or oval5. linear or curvilinear

6. lobulated

7. amorphous - not recognizable shape

Calcifications: What's common?

1. costal cartilages, both in the chest and in the abdomen (great mimicker of pathology)

2. phleboliths - little stones that form in veins. common in pelvis

3. atherosclerotic plaques in the aorta and common iliac arteries

4. calcified lymph nodes

5. ingested but indigestible materials

Calcifications: What is less common?

1. gallstones

2. renal stones

3. atherosclerotic femoral and pelvic arteries

4. uterine fibromas

5. prostate calcification

6. injection granulomas

7. adrenal calcifications

8. splenic calcifications

9. hepatic calcifications

Calcifications: What is rare?1. porcelain gallbladder

2. milk of calcium bile

3. nephrocalcinosis

4. hepatic and splenic granulomas and cysts

5. ovarian dermoid cysts

6. vas deferans and seminal vesicles

7. splenic and renal artery aneurysms

8. cancerous (psamomma)

Abnormal calcifications:

Atherosclerosis of the aorta

-Atherosclerosis most commonly occurs between L2-L4 (between the renal and the common iliac arteries)

-Although etiology is unknown, it is closely associated with elevated levels of cholesterol and triglycerides

-Atherosclerosis is a risk factor for aneurysm

-Other risk factors include:

a. age: over 50 years

b. gender: mostly males

c. hypertension

d. smoking


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Diagnostic Imaging I Class Notes Page 14 of 24- Plain film findings of aortic atherosclerosis

-irregular, vertically oriented linear calcifications are seen anterior to the lumbar spine. the degree of

calcification may be minute or extensive.

-the calcifications may be either in the anterior or posterior wall or both.

-When calcification is extensive, the central portion of the artery may appear slightly opacified but is

uncommon.

-When calcification is present in both the anterior and posterior walls, the sagittal diameter should be

measures.-Whenever the sagittal diameter is greater than 3 cm (30 mm) (about 1 inch), aneurysm is present.

-Whenever vascular calcifications are seen on AP views, lateral to the vertebral bodies (usually on the

left side and curvilinear), aneurysm is suggested.

-Abdominal ultrasound is the usual follow-up for confirmation

-Any patient with a confirmed aneurysm should be referred for a surgical consultation, although surgery

is usually not performed on aneurysms under 5 cm.

-Aneurysms tend to progress over time.

-aneurysm greater than 7 cm usually ruptures and is fatal 50% of the time.

Abdominal aneurysm

-The most common location is between L2-L4 (between the renal and common iliac arteries)

-It may be seen on the AP view on the left side of the spine & bilaterally if large enough.

-Aneurysm may cause erosion into the anterior vertebral body from pressure & pulsation ( Anterior Scalloping is

the term for the concave defect).

-Aneurysms are often asymptomatic, but the following symptoms may be found:

a. LBP, can be localized or radiating

b. Abdominal pain

c. Flank pain

-The following physical examination findings may suggest the presence of abdominal aneurysm:

a. bruit

b. palpable mass (especially if pulsitile)

c. decreased lower extremity blood pressure (compared to the arm)

d. decreased pedal pulse amplitude.- Types of Aneurysm:

1. True Aneurysms: represent a dilation of all three layers of the aorta, creating a localized bulge of the

vessel wall in either of these shapes:

a. fusiform: more common, entire circumference of the aorta is dilated

b. saccular: localized out pouching involving only a portion of the circumference.

2. False aneurysm (Pseudoaneurysm & dissecting aneurysm)

- represents a contained rupture of the vessel wall (intimal and medial layers) that mimics true

aneurysm

-painful

-lesions are unstable and prone to rupture

-posteriorly located, near spine

Atherosclerosis of the Common Iliac Arteries

-Calcifications appear as diverging (from superior to inferior) conduits over L5 & the sacrum on A-P Lumbopelvic

views.

-The bifurcation demonstrates plaqueing or a ring on the lateral film.

-2/3 of all abdominal aortic aneurysms extend into the common iliac arteries.

Venous Calcifications (Phleboliths)

-Phleboliths are calcified venous thrombi.

-They are round or oval in shape, 1.5 - 5 mm in size, often with a lucent center.


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Diagnostic Imaging I Class Notes Page 15 of 24-Most often 1-6 are found, but 2-3 dozen may be found.

-They are usually found next to the pelvic rim below the ischial spines.

-They are clinically insignificant.

-If found outside of the pelvic rim or in the midline, enlarging mass is usually suspected except in:

1.female who had a hysterectomy (they may be midline)

2. distended bladder (may be inferior and/or lateral)

Costal Cartilage Calcification/Calcinosis/CCC:-Idiopathic although may be hormonally influenced.

-Clinically insignificant, once recognized, but this may be difficult as the usual course of the costal cartilages is

widespread.

-CCC may resemble abdominal calculi or pulmonary nodules. The great imitator of soft tissue pathology.

-"Railroad Track" sign is often seen in males as the periphery calcifies.

-"Wagging Tongue" sign is commonly seen in females as the center calcifies. Round densities also may be seen.

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Magnetic Resonance Imaging (MRI)

How does MRI work?

1. Magnetization: High magnetic field is applied externally to align the unbound Hydrogen protons in the body

in a parallel (or antiparellel) orientation.

2. Excitation: A radiofrequency (RF) that matches the Larmor frequency of the magnetic field is applied to excite

the H protons. As the protons absorb energy, they "flip" off of the axis of the magnetic field. Manipulation of

the RF pulse allow protons to reach a specific flip angle (90 deg. or 180 deg. for spin echo)

3. Relaxation: RF is turned off to allow the H protons to realign themselves while giving off the energy absorbed

during excitation. The RF energy given off is measured by the detector.

95% of chiropractic referrals are MRI referrals.

BASICS of CONCEPTS:

- Some nuclei in the human body have magnetic properties. Hydrogen nucleus has a magnetic moment (a net

spin), because it has 1 proton and 0 neutrons. It acts like a gyroscople, but has a secondary wobble, therefore

acts sort of like a bar magnetic.

There are two main types of hydrogen protons in the body

- OH (water)- CH3 (fat)

What happens inside the MRI machine. There are several steps:

1. At rest, all the protons cancel each other out so that there is no net magnetization in our body. The MRI first

creates a magnetic field (10's of 1000's of times stronger than earth's magnetism). The strong magnetic effect

causes the hydrogen protons in the body to line up either with or against the magnetic field (analogy: North

faces north, south faces south)

2. Excite the hydrogen protons to a higher energy level by introducing radio waves. The radiofrequency (RF)

used depends on the field strength. This is called the Larmor frequency (it causes things to resonate with the

magnetic field.).

The RF causes the axis of the hydrogen protons to flip at right angles to the magnetic field.

3. When the RF is turned off, the hydrogen protons want to go back to their original position. As they do, theygive off radio waves they had previously absorbed. This energy is measured by the detector in the machine.

MRI Resonance

The hydrogen protons absorb the RF energy and are excited in 2 ways:

1. Flippin away from the main magnetic field= flip angle. Usually 90 degrees fro spin echo imaging.

2. Precessing in phase. Precession is the wobble of the spinning proton, similar to a gyroscope. In phase

precession is quickly lost after the RF is off s a "refocusing" RF is usually applied. this achieved by a second RF

pulse, with a 180 degree flip angle in spin echo imaging, or by reversing the gradient in gradient or field echo

imaging. Essentially that coordinates the wobbling protons.


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How the contrast is created in MRI

-Based on a couple of factors: the relaxation times of the fat versus of the water differs and depending on when they

turn on the "antennae" to detect determines what you see. This is called image weighting.

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cont…Calcifications:

Renal Calculi (aka nephroliths, nephrolithiasis, roliths, urolithiasis, kidney stone)-risk factors: hyperparathyroidism, infections, steroids, thiazide diuretics, and bone tumors

-located in the collecting system

-80-90% are opaque and are visualized/positive on plain films (without contrast)

-recurrence is common

Kidney stones

-may be asymptomatic

-low back and/or flank pain is common

-common cause of obstruction of the urinary tract

-tend to be colicky pain (spastic cramping)

-homogeneously dense 9distinctive from other stones that are ringed or laminated)-varies in size and shape (round, oval, or irregular)

-if fills the calyces or the entire renal pelvis = Staghorn calculi

- calculi are seen paraspinally between L1 - L4 on an A-P upright film (right kidney typically)

-on lateral views, they overlap the spine (as opposed to gallstones)

Ureteral Calculi

-80-90% are visible on plain film - ureters overlie the TVP's from L3-L5

-homogeneously dense

-oval or irregular in shape

-usually measures 1-3 mm but can be larger (5 mm or so)

-Common sites of obstruction:

1. pelvicoureteral junction2. pelvic brim

3.vesicoureteric junction (where the ureter meets the bladder) (slightly medial to the ischial spine, most

common)

-Extremely painful when passing a stone

-Can cause hydronephrosis (backup of urine into the kidney) when obstruction occurs

-Most ureteral stones pass spontaneously within 3-4 days

Bladder Calculi (Vesicle Calculi)

-80-90% are visible on plain film.

-They are usually large and are round or oval.

-The stones may be homogeneous, laminated, or ringed.-Urinary stasis is the most common cause.

-Long standing infection or foreign body may also cause it.

-They are most common in elderly males and paraplegics

-Stones are usually located in the suprapubic region near the midline.

Nephrocalcinosis

-Nephroalcinosis refers to a pathophysiologic condition in which the calcium is deposited within the renal

parenchyma.

-It results from conditions that elevate the serum calcium level.

-Common causes include hyperparathyroidism, renal tubular acidosis, metastatic bone disease, TB, medullary


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Diagnostic Imaging I Class Notes Page 17 of 24sponge kidney, and milk alkali syndrome.

-Appears as clumps of punctate calcifications within the kidney parenchyma.

Cholelithiasis (Gall Stones)

-Only 10-20% are radiopaque (positive stones); most gallstones are radiolucent (negative stones). They usually

imaged via Sonography (diagnostic ultrasound)

-Often asymptomatic

-May, however, be associated with RUQ and/or right scapular pain, recurrent cholecystitis, obstruction of theduct, perforated gall bladder wall with fistula formation, or small bowel obstruction (gallstone ileus).

-Risk factors for cholecystitis = the 5 F's (fat, female, forty, fertile, flatulent)

-They are usually multiple in number.

-Location: RUQ on frontal views and anterior to the spine on Lateral views. On Oblique views, they shift away

from the spine due to their more anterior location.

-Faceted surfaces, peripheral rim of calcification, laminated appearance, or Y-shaped internal lucent cracks,

("Mercedes Benz" or "Crow Foot" sign) characterize gallstones.

- Lucent cracks may even be visible within "negative" (water density) gallstones.

Porcelain or Petrified Gallbladder

-Etiology is unknown but is often associated with chronic chelecystitis.

-A thin linear calcification is seen in the gall bladder wall.

-The calcification is usually pear shaped, ovoid or round.

-More common in females than in males.

-Most patients are asymptomatic although cystic duct obstruction is common in these individuals.

-Carcinoma occurs in 20% of cases, therefore, prophylactyic removal is the usual treatment.

Milk of Calcium Bile

-Rare

-The bile stored in the gall bladder contains a large amount of calcium carbonate thus the gallbladder appears

very dense on plain film.

-Lucencies may be seen within the calcified milk if negative stones are present.

-Upright film may demonstrate a horizontal fluid level.

Pancreatic Calcifications

-Frontal views show numerous punctate (stippled) upper quadrant densities on both sides of the spine (75% of

the time) but may be localized in the head of pancreas (25%)

-Anterior to the spine on lateral views.

-Usually results from chronic alcoholic pancreatitis.

-Other causes include chronic calcifying pancreatitis, nutritional pancreatitis, hyperparathyroidism, and cystic

fibrosis.

Adrenal gland calcification:

-Adrenal gland is located on top of the kidney paraspinally at the level of L1 on an upright film.-Overlaps the spine on the lateral view

-Calcification may be benign or malignant

-Usual patterns of calcifications are punctate and cystic. Punctate is small, solid and multiple whereas cystic is

curvilinear or ringed and usually singular.

-Common causes include healed TB, histoplasmosis, Addison's disease, tumors (benign and malignant), and

neonatal hematoma.


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Lymph node calcifications

-Most commonly after granulomatous infections.

-Calcifications are clumped into clusters creating a mulberry-like appearance.

-They usually have lobulated borders and have mottled interior.

-They are often multiple but can be singular.

-They are usually 1-2 cm in size, but can be as large as 7cm

-They may be found anywhere in the abdomen (R>L)-Calcifications suggest healed infections, mostly TB & histoplasmosis (no clinical significance)

-Para aortic and scrotal lymph nodes may also calcify

-Again, insignificant (once recognized)

-Calcification can be mimicked by residual contrast from a lymphangiogram if oil-based contrast was used.

Uterine Fibroma (Leiomyoma)

-Most common calcifications of the female reproductive tract

-By the time that they calcify, patients are usually > 40 years old

-Usual appearance is flocculent, speckled/irregular & rounded ("popcorn-ball"). Single or multiple

-Located within the pelvic inlet above the usual site of bladder stones, but can be found in the abdomen when

large.

-Usually asymptomatic, but may cause acyclic bleeding, abdominal pain, or infertility in some individuals.

Dermatoid Cyst (Ovarian Teratoma)

-Most common ovarian calcific mass

-Dermoids are localized ectopic accumulation of ectodermal tissues. Primitive teeth, hair & bone are often

present. So is fat.

-Represents 10% of all ovarian tumors

-They are most often found in the ovaries, but can be found elsewhere in the body. (in the lung they are

hamartomas)

-May cause abdominal pain, constipation, or abnormal bleeding but are often asymptomatic.

-May be solitary or multiple, and can be bilateral (10-20%)

Prostate Calcification

-Usually found in males > 40 years old

-Usually appear as multiple, small, punctate calcifications superimposing symphysis pubis.

-Prostatic enlargement is suspected when found superior to symphysis pubis.

-They are usually associated with chronic prostatitis or infection.

-If asymptomatic, it is clinically insignificant.

Psoas Abscess

-They are usually associated with TB of the spine/Pott's disease. This is usually found at the T-L spine

-Necrotic debris forms an abscess which may dissect along the psoas fascia.

-Calcification of the abscess is suggestive of healed infections (TB) and is called a "cold abscess".-May be seen along the course of the psoas (paraspinal from L2-L5 and down to the lesser trochanter)

Splenic Artery Atherosclerosis and Aneurysms

-Normally


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Splenic/Hepatic Calcifications

-Usually granulomas from previous infections (most commonly TB and histoplasmosis)

-Calcifications are usually small, round, solid, or scattered (punctate)

-Infarcts can be seen as multiple or solitary densities.

-The entire spleen may appear more dense in individuals with sickle cell anemia.

Cyst Calcifications

-Most abdominal cysts do not calcify-when calcified, curvilinear rim is observed.

-Cysts are usually solitary and may be round, ovoid, or flattened in shape

-Calcified cysts my be seen in several locations including the kidneys, spleen & liver

-splenic cysts may be due to trauma/hematoma

-Splenic or hepatic cysts may occur in Hydatid disease (echinococcal infection)

Calcification of Connective Tissues

-Ligaments, tendons, & fascia may have physiologic or pathologic calcifications

-Physiologic (insignificant) ligament calcifications; ilio-lumbar, sacrotuberous & pectineal (Cooper's)

-Pathological calcifications: HADD, CPPD, myositis ossificans, etc. - covered in 8Q & 9Q

Appendicoliths: aka Coproliths & appendiceal fecaliths

-Most common fecalith in children and in adults.

-Appears as a homogenous, laminated, or ringed stone in the appendix.

-Usually small but can be as large as 4cm

-Located in the RLQ- often superimposes the ilium

-Often associated with appendicitis. (There is a much higher rate of rupture if found with appendicitis.) Surgery

is usually performed prophylactically.

-May be found in asymptomatic patients.

Enteroliths/Fecaliths

-Besides the appendix, fecaliths may form in other locations

-In a Meckel's diverticulum-In the sigmoid colon & the rectum. Due to stasis from luminal narrowing or within diverticula.

Injection Granuloma

-They are round or oval densities with peripheral calcific rim.

-they are usually within the gluteus maximus muscle. Lateral to the inominates on frontal views.

-Fat necrosis from previous injections (most commonly insulin and antibiotics) is the cause

-They may be painful at times, but are clinically insignificant

-See Yochum & Row, Ch. 16, pp 1413-1414

Foreign bodies

-Ingested - tablets, pills, buckshot, coins, and toys, etc.-Traumatic - bullets, shrapnel, nails, buckshot, etc.

-Inserted - body jewelry, tampons, IUD's, dildos, etc.

-Post surgical - staples, sutures, vascular clips, prosthetic devices, etc.

Bowel Gas Patterns

-Gas visualized on the abdominal film may be intraluminal (sometimes abnormal) or extraluminal (always

abnormal). Some intraluminal gas is normal. total absence of rectal gas usually indicates obstruction.

-Multiple air-fluid levels, distension or displacement of one or more bowel loops, or thickening of the mucosa

are the plain-film abnormalities. (This paragraph is important)


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Intraluminal Gas: Stomach

-Gastric air bubble (Meganblase) is normally seen beneath the left hemidiaphragm on the upright film.

-The rugae may be visible as a striated pattern in the body.

-Displacement is associated with:

1. medial displacement - splenomegaly

2. anterior displacement - pancreatic enlargement

3. lateral displacement - hepatomegaly

4. superior displacement - hiatal hernia

Intraluminal Gas: Small Intestine:

-The width is usually less than 3 cm

-Only a minimal amount of gas should be seen normally in adults. Up to 3 air-fluids levels is probably OK.

-Air in jejunum appears as a "coiled spring" or "stack of coins" due to plicae semicircularis. On the contrary, air

in the ileum appears as a smooth air filled tube due to lack of plicae semicircularis.

1. aka: Valvulae Conniventes

Intraluminal Gas: Large Intestine:

-Colon diameter > 5 or 6 cm or Cecum diameter > 9 cm = dilation.

-Haustra appears as indentations in the gas column. Disconnected collections of gas us a usual pattern in thelarge intestine.

-Normal density of the fecal material varies depending on its composition. Dense collections of feces is usually

found in the distal colon.

-Gas is normal as long as it does not cause distention of the bowel.

-Rectal gas is normal

-Air-fluid levels are abnormal except after enemas.

Ileus

- Def.: obstruction of the intestines

- Types:

a. Dynamic/Mechanical/Obstructive Ileus - complete or partial mechanical blockage. Clinically bowel

sounds are increased initially.b. Adynamic/Paralytic/Reflex Ileus - temporary arrest of intestinal peristalsis in the absence of a physical

obstruction. Clinically bowel sounds are decreased or absent.

- Dynamic Ileus: small bowel obstruction:

- In the small bowel, a cascade of distended loops are seen proximal to the obstruction with little or no

gas distal to the obstruction.

-The bowel loops frequently present with a stepwise or cascading appearance and hair-pin /180 degree

turns.

-Air-fluid levels may be present (+/-) on upright views and may also form a stepladder or cascading

pattern.

-In adults, the most common cause of dynamic small bowel ileus is post-surgical adhesions. In children,intussusception is the main cause.

-Other causes include post-infectious adhesions, tumors & gallstones ileus.

- Dynamic Ileus of the large intestine:

-If the ileocecal valve is competent, distension will be seen from the obstruction up to the cecum and

cecal distension (>9 cm) is specific. when the cecum measures >12 cm, perforation is imminent. If the

valve is incompetent, small bowel distension will also be seen and the pattern is non- specific.

-Most common cause of dynamic ileus of the large bowel in adults is cancer, diverticulitis and volvulus


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- Volvulus:

-The bowel may twist upon itself, (kinking, like a hose) causing an obstruction

-Most likely in the sigmoid colon of geriatric patients

-X-ray shows large bowel obstruction, possibly with an inverted U-shaped loop of bowel pointing toward

the liver.

- Adynamic Ileus (Paralytic/Reflex Ileus)-Usually self-limiting

-There is a balanced distribution of gas and distension in both the colon and small bowel. Mild stasis

pattern in the small bowel and distension of colon are typical. Air-fluid levels may be present.

-The rectum usually contains gas.

-Most common cause is trauma (T-spine & L-spine included). Other causes include recent abdominal

surgery, peritonitis, drugs, chronic illness, and hypothyroidism.

-Localized adynamic ileus (Sentinal Loop) usually suggests inflammation of an adjacent structure. May

be seen in appendicitis and cholecystitis.

Extraluminal Gas: Pneumoperitoneum

-Represents free air in the peritoneal cavity.

-The most common cause is a perforated GI tract or a surgery.

-Causes of perforation in the GI tract include:

1. duodenal ulcer (mc)

2. colonic diverticulum

3. gastric ulcer

4. gallbladder perforation

5. traumatic rupture of the GI tract

-Pneumothorax may cause pneumoperitoneum or visa versa!

- Radiographic findings of Pneumoperitoneum:

-Air is usually seen under the hemidiaphragm(s) (especially above the liver) on an upright chest, spine or

abdominal film.

-Falciform ligament may become visible due to air in the abdomen (highly diagnostic).-Lateral decubitus views may also be used if patient can't stand uupright.

-Recumbent A-P view may show "double wall sign" - air inside and outside loops of bowel.

Extraluminal Gas: Loculated/Contained (This is rare)

-Contained gas is sometimes seen in an abscess cavity. It may be lucent or bubbly & may be difficult to

distinguish from intraluminal gas.

-Retroperitoneal gas collections may for due to perforation of duodenal ulcers. This may result in enhancement

of the psoas muscle shadow.

-Rarely, gas may be contained within the bowel wall, the biliary tree or the portal veins of the liver.

Enlargement of Abdominal Organs:-Splenomegaly shifts the gastric air medially. The splenic border is below the costal margin. The left kidney is

inferiorly displaced.

-Hepatomegaly elevates the right hemidiaphragm & displaces the hepatic flexure inferior-medially. Liver border

may go below the L4-5 IVD level.

-Enlarged pancreas causes the stomach to shift anteriorly.

-Enlarged adrenal gland or enlarged paraspinal lymph nodes may shift the kidney inferiorly.

- Evaluation of the Abdominal Organs:

-Organs may appear smaller if

1. underdeveloped or

2. atrophied


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Diagnostic Imaging I Class Notes Page 22 of 24-Organs may appear larger if

1. engorged

2. tumorous

3. swollen

4. overdeveloped to compensate an underdeveloped or undeveloped structures.

-Organs may appear displaced if

1. the film is taken upright

2. adjacent structure is enlarged or a mass is growing near the structure3. ectopic

Hiatal Hernia

- Def: a portion of the stomach herniates through the esophageal hiatus of the diaphragm

-Types:

1. Sliding/Axial - 95%, very common, very dynamic, esophageal-gastric junction herniates through hiatus

2. Paresophageal - the esophageal-gastric junction remains below the diaphragm, but a portion of the

gastric fundus herniates into the chest next to lower esophagus.

-Radiographic Findings: The meganblase superimposes the cardiac shadow in frontal views, appearing as a hole

in the heart. On lateral views the meganblase is usually posterior to the cardiac shadow but may partially

superimpose it.

Other diaphragmatic hernias:

-Bochdalek's - bowel or other abdominal organ herniates into the chest through the posterior portion of the

diaphragm, 3 B's = Big, Back, & Bowel

-Morgagni's - omentum or bowel herniates retrosternally (anteriorly), usually small

-Traumatic - severe trauma causes abdominal organs to herniate above the diaphragm, mostly on the left side in

the posterior, central aspect of the diaphragm (aka - traumatic rupture)

-Complications: Strangulation & infarction especially common in traumatic hernias.

Ectopia of the Abdominal organs:

-Congenital anomalies:

1. Horseshoe kidney - lower poles fused and therefore are oriented medially2. Intrapelvic kidney

3. Intrathoracic kidney

4. Ptosis of the kidney - inferior displacement of greater than 5 cm or 1.5 vertebral body heights upon standing

5. Situs inversus refers to complete transposition of the abdominal organs. May also include the heart

(dextracardia). Extremely rare.

Abnormal fluid: Ascites

- Diffuse, ground-glass appearance in the abdomen with loss of visable soft tissue detail.

-Clinically apparent (does not require x-rays for diagnosis).

-Accumulation of fluid may result in displacement of the abdominal organs such as the flank stripes (lateral

convexity is abnormal) colon, liver, and spleen.-CT and Diagnostic Ultrasound are more useful in diagnosing ascites.

Other Imaging Modalities:

Contrast Enhanced Radiography

-Used when inherent contrast differences does not exist between the structure of interest and its surrounding

tissues (ex: gastrointestinal tract, urinary tract, and blood vessels)

-Contrast (metallic) agents such as barium and iodine are used to opacify organs/structures

-Contrast enhances the anatomy and by using FLOUROSCOPY there is visualization of movement of the contrast

(physiologic function)


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Diagnostic Imaging I Class Notes Page 23 of 24-The contrast agent may have to be circulated via IV injection, absorbed &/or excreted at a target organ, again

producing physiologic information.

-Contrast agents may cause mild to severe adverse reactions.

Contrast Enhanced Radiography: Gastrointestinal tract

-Contrast agent (usually Barium Sulfate) is administered alone = single contrast or in combination with air, or a

mixture that produces carbon dioxide = double contrast.

-Contrast agents are administered either by mouth (upper GI exam/Barium swallow) or by rectum (lower GIexam/Barium enema)

-Water soluble contrast may be used if leakage of the contrast material beyond the bowel wall is possible

Contrast Enhanced Radiography of the Urinary Tract:

-Common Terms: Urography, Intravenous urogram (IVU), Intravenous pyelogram (IVP)

-Water soluble iodinated salts of diatrizoic or iothalmac acids the nonionic agents such as iopamidol or iohexol

are often used

-IVU is being replace by spiral CT nowadays.

Angiography:

-Water soluble agents are injected either intraarterially (arteriography) or intravenously (venography)

-Course of the contrast material through the blood vessels is followed by rapid sequence of exposures.

-Computed tomography &/or fluorography may also be utilized.

Ultrasonography: Diagnostic ultrasound

-Non-invasive, safe and inexpensive

-Methods of choice for evaluating the biliary system

-Usual follow-up (after x-ray) for abdominal aortic aneurysm

-Routinely used to monitor fetal development during pregnancy.

Computed Tomography (CT)

-CT is used extensively in the abdomen

-Conventional CT is often used during contrast exams to provide planer images-Non-contrast helical CT is often able to image kidney stones and other masses.

Fiber Optics:

- Examples include sigmoidoscopy, laparoscopy, endoscopy, and colonoscopy (laparoscopy requires minor

surgery)

-In addition to direct imaging, fiber-optic allow for the collection of tissue samples and microsurgical

techniques/treatment.

Breast imaging:

1. Plain Film Mammography - primary screening technique for breast cancer.

2. Breast Ultrasound - sused as an adjunct to mammography. Primary application is to detect fluid within a massseen on a mammogram

3. MRI - utilization of the MRI is uncertain at present, however, this is a rapidly developing area.

Plain Film Mammography

-Costs approximately $250

-Uses a radiographic film and screen combination that provides high detail with relatively low radiation (300 mR)

-Mammography has the highest accuracy for detecting occult breast cancer.

-It is also used to localize a mass for surgical excision (lumpectomy).


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Evaluation of the Female Breast: American Cancer Society Guidelines:

- Asymptomatic Women

1. Women 20 years of age and older should perform breast self-examination monthly.

2. Women age 20 to 40 should, in addition, have a physical examination of the breasts every 3 years.

3. Women at age 40 should have a mammogram.

4. Women 40 years of age and older should have a mammogram and a physical examination of the

breast every year.- Symptomatic Women

- symptomatic women with a dominant breast mass, persistent discomfort, skin dimpling, or nipple

discharge should have a thorough breast examination that includes mammography and any other

diagnostic study (ultrasound) to determine if cancer is present. These studies should be performed

regardless of the patient's age.

END OF FINAL MATERIAL

DX Imaging 1 MT and Final

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