IMAGING for IMAGING for ABDOMINAL PAINABDOMINAL PAIN

42 y.o., obese woman with 6 42 y.o., obese woman with 6 children. Now has RUQ pain and children. Now has RUQ pain and

tenderness, fever, elev. WBC. Pain tenderness, fever, elev. WBC. Pain radiates around to under right radiates around to under right

scapulascapula

This is a classic history for acute cholecystitis, although ascending This is a classic history for acute cholecystitis, although ascending cholangitis may present similarlycholangitis may present similarlyThe standard imaging is RUQ ultrasoundThe standard imaging is RUQ ultrasoundIn abdomen, where is US good, where isn’t it, and why?In abdomen, where is US good, where isn’t it, and why?Enemies of US are gas and bone, which reflect and don’t transmit soundEnemies of US are gas and bone, which reflect and don’t transmit soundThree “big” areas for US in the “abdomen” are the RUQ, kidneys, and Three “big” areas for US in the “abdomen” are the RUQ, kidneys, and pelvis, because all three can provide a sonographic window without bowel pelvis, because all three can provide a sonographic window without bowel gas in the way (liver displaces bowel out of the RUQ, kidneys can be gas in the way (liver displaces bowel out of the RUQ, kidneys can be imaged from the flanks, urinary bladder can be filled to lift bowel out of the imaged from the flanks, urinary bladder can be filled to lift bowel out of the pelvis or trans-vaginal and trans-rectal US can get directly to uterus/ovaries pelvis or trans-vaginal and trans-rectal US can get directly to uterus/ovaries and prostate without intervening bowel)and prostate without intervening bowel)Also, US is great for fluid (seeing through GB bile to see stones, seeing Also, US is great for fluid (seeing through GB bile to see stones, seeing dilated bile ducts, determining if renal lesion is cyst or solid, seeing through dilated bile ducts, determining if renal lesion is cyst or solid, seeing through urinary bladder)urinary bladder)Pregnant uterus is perfect for US (sonographic window with uterus Pregnant uterus is perfect for US (sonographic window with uterus displacing bowel, amniotic fluid to transmit sound well, no ionizing radiation)displacing bowel, amniotic fluid to transmit sound well, no ionizing radiation)

US findings in acute cholecystitisUS findings in acute cholecystitis– GB stonesGB stones– Tender GB (sonographic Murphy’s sign)Tender GB (sonographic Murphy’s sign)– Distended GBDistended GB– Thickened GB wallThickened GB wall– Pericholecystic fluidPericholecystic fluid– Debris/pus in GB lumenDebris/pus in GB lumen– Hyperemia on color DopplerHyperemia on color Doppler

Of radiology imaging modalities, US is unique Of radiology imaging modalities, US is unique in that it combines simultaneous physical in that it combines simultaneous physical exam with imagingexam with imaging

Following image shows stone in GBFollowing image shows stone in GB

Findings diagnostic of GB stoneFindings diagnostic of GB stone– Echogenic focus in GB lumenEchogenic focus in GB lumen– Acoustical shadowingAcoustical shadowing– Mobile (moves with change in position of Mobile (moves with change in position of

patient)patient)

HIDA scan is alternative imaging if GB not visible on USHIDA scan is alternative imaging if GB not visible on USFollowing HIDA scan shown as typical example of nuclear Following HIDA scan shown as typical example of nuclear medicine studymedicine study– Uses Technicium 99mUses Technicium 99m– What lights up depends on what carrier molecule is attachedWhat lights up depends on what carrier molecule is attached– Compared to other radiology imaging modalities, nuclear studies Compared to other radiology imaging modalities, nuclear studies

are only partly about imaging anatomy (the anatomy is typically are only partly about imaging anatomy (the anatomy is typically “fuzzy” on nuclear imaging), but it is also very much about “fuzzy” on nuclear imaging), but it is also very much about function and physiology (more than other modalities)function and physiology (more than other modalities)

This HIDA shows serial images of counts obtained at 5-This HIDA shows serial images of counts obtained at 5-minute intervals, with normal activity entering GB, giving minute intervals, with normal activity entering GB, giving functional information that cystic dust is patent, making acute functional information that cystic dust is patent, making acute cholecystitis unlikelycholecystitis unlikely

14 y.o girl who initially had crampy, 14 y.o girl who initially had crampy, periumbilical pain, that is now more periumbilical pain, that is now more

steady and localized to the RLQ. steady and localized to the RLQ. Has focal tenderness in RLQ, Has focal tenderness in RLQ,

mildly increased WBC, and slight mildly increased WBC, and slight fever.fever.

The history suggests acute appendicitisThe history suggests acute appendicitisWith a classic history and physical for appendicitis, in the With a classic history and physical for appendicitis, in the hands of an experienced surgeon, no imaging may neededhands of an experienced surgeon, no imaging may neededImaging is otherwise needed, particularly if the history or Imaging is otherwise needed, particularly if the history or exam is atypical exam is atypical Plain X-rays would not be indicated because usually Plain X-rays would not be indicated because usually appendicitis would be soft tissue/fluid pathology against a appendicitis would be soft tissue/fluid pathology against a normal soft tissue background (no contrast) and would be normal soft tissue background (no contrast) and would be invisibleinvisibleFollowing X-ray shows a calcified fecalith (appendicolith) Following X-ray shows a calcified fecalith (appendicolith) projected just lateral to right SI joint in patient with projected just lateral to right SI joint in patient with appendicitis, but this is very insensitive sign, visible on X-ray appendicitis, but this is very insensitive sign, visible on X-ray in fewer than 5% of casesin fewer than 5% of cases

Although CT is an excellent imaging exam for appendicitis Although CT is an excellent imaging exam for appendicitis (95%+ sensitivity and positive predictive value), radiation is an (95%+ sensitivity and positive predictive value), radiation is an issue, particularly in a young patientissue, particularly in a young patientHow much radiation does patient get with abdominal/pelvic How much radiation does patient get with abdominal/pelvic CT?CT?– PA CXR gives only about 3-days-worth of radiation that we all PA CXR gives only about 3-days-worth of radiation that we all

get anyway from natural sourcesget anyway from natural sources– Abdominal and pelvic CT may give as much as 100 times Abdominal and pelvic CT may give as much as 100 times

radiation of PA CXRradiation of PA CXRWhat is risk of the radiation from A/P CT?What is risk of the radiation from A/P CT?– Very little prospective dataVery little prospective data– Worst case guess: Out of 1000 A/P CTs in pediatric patient, may Worst case guess: Out of 1000 A/P CTs in pediatric patient, may

cause one additional cancer in a lifetimecause one additional cancer in a lifetime– Always need to weigh risk versus benefit (CT information may Always need to weigh risk versus benefit (CT information may

provide very large benefit)provide very large benefit)

For pediatric patient, as long as radiology For pediatric patient, as long as radiology dept. has experience, US is preferred over dept. has experience, US is preferred over CT for initial imaging of suspected CT for initial imaging of suspected appendicitisappendicitis

Although its sensitivity is not as good as Although its sensitivity is not as good as that of CT when used on all patients, US is that of CT when used on all patients, US is effective in smaller pediatric patients, has effective in smaller pediatric patients, has no radiation, and has a very high positive no radiation, and has a very high positive predictive valuepredictive value

Findings of appendicitis on USFindings of appendicitis on US– Dilated (usually >6mm), non-compressible, Dilated (usually >6mm), non-compressible,

tender bowel-like structure in RLQ attached to tender bowel-like structure in RLQ attached to cecumcecum

– No peristalsisNo peristalsis

– May see closed end, appendicolith, hyperemia on May see closed end, appendicolith, hyperemia on color Doppler, adjacent inflamed fat or abscesscolor Doppler, adjacent inflamed fat or abscess

Following image shows abnormal appendix Following image shows abnormal appendix on US in patient with appendicitison US in patient with appendicitis

Following images show appendicitis on CTFollowing images show appendicitis on CTTo review a CT, scroll up and down (visually in this case) To review a CT, scroll up and down (visually in this case) through images to integrate the slices into a 3-D mental image through images to integrate the slices into a 3-D mental image of one structure at a time (liver, each kidney, colon, etc.)of one structure at a time (liver, each kidney, colon, etc.)Oral barium has been given in this case, opacifying the ileum Oral barium has been given in this case, opacifying the ileum making it easier to identify the appendicitis (since its lumen is making it easier to identify the appendicitis (since its lumen is obstructed and will not fill with contrast)obstructed and will not fill with contrast)For appendix, find ascending colon in right flank, follow down For appendix, find ascending colon in right flank, follow down to tip of cecum, and appendix will be recognized as tubular to tip of cecum, and appendix will be recognized as tubular structure off cecum, but only if one mentally integrates the structure off cecum, but only if one mentally integrates the slices going inferiorlyslices going inferiorlyThe appendix is dilated, and has “fuzzy fat” around it The appendix is dilated, and has “fuzzy fat” around it (inflamed, edematous mesenteric fat)(inflamed, edematous mesenteric fat)

Following coronal image on patient with Following coronal image on patient with appendicitis shows appendicolith in dilated appendicitis shows appendicolith in dilated appendixappendix

Multidetector spiral CT rapidly obtains very Multidetector spiral CT rapidly obtains very thin axial slices, allowing acquisition of a thin axial slices, allowing acquisition of a volume of data, and subsequent volume of data, and subsequent reconstruction of multi-planar imagesreconstruction of multi-planar images

70 y.o. male with fever, increased 70 y.o. male with fever, increased WBC, and LLQ pain and WBC, and LLQ pain and

tendernesstenderness

This is typical history for diverticulitis, most This is typical history for diverticulitis, most commonly involving the sigmoid coloncommonly involving the sigmoid colonPlain X-rays not usually helpful because it’s Plain X-rays not usually helpful because it’s soft tissue/fluid pathology on soft tissue soft tissue/fluid pathology on soft tissue background, although some complications of background, although some complications of diverticulitis (free intraperitoneal perforation, diverticulitis (free intraperitoneal perforation, obstruction) could be imaged on X-rayobstruction) could be imaged on X-rayUS not usually used because there is no US not usually used because there is no good sonographic window, and patients are good sonographic window, and patients are olderolder

Following CT images show sigmoid diverticulitisFollowing CT images show sigmoid diverticulitisVisually scroll through the images to follow the Visually scroll through the images to follow the descending colon down to the sigmoid, where the descending colon down to the sigmoid, where the colon wall and mucosal folds are very thickenedcolon wall and mucosal folds are very thickenedAlso note the “fuzzy fat” around the sigmoid, due Also note the “fuzzy fat” around the sigmoid, due to inflammation/edemato inflammation/edemaThis case is uncomplicated diverticulitis, without This case is uncomplicated diverticulitis, without macroscopic abscess, which if of sufficient size macroscopic abscess, which if of sufficient size would require drainage, usually by interventional would require drainage, usually by interventional radiologyradiology

40 y.o. male with intermittent 40 y.o. male with intermittent severe right flank pain radiating to severe right flank pain radiating to

groin, and hematuriagroin, and hematuria

The likely diagnosis is a right ureteral stoneThe likely diagnosis is a right ureteral stoneBecause the most common ureteral stone composition is Because the most common ureteral stone composition is calcium oxalate, they are often visible on plain X-ray (but only calcium oxalate, they are often visible on plain X-ray (but only about 60% since many stones measure only a few mm, hard about 60% since many stones measure only a few mm, hard to see in a large patient)to see in a large patient)Therefore X-ray not usually used for initial dx, although helpful Therefore X-ray not usually used for initial dx, although helpful for urologic F/Ufor urologic F/UCT is gold-standard imaging study for showing ureteral stones CT is gold-standard imaging study for showing ureteral stones (nearly 100% sensitivity), based on original literature articles (nearly 100% sensitivity), based on original literature articles from Yale Radiology Dept.from Yale Radiology Dept.ButBut, CT has issue of radiation, particularly in patients who , CT has issue of radiation, particularly in patients who may be young and repeatedly present in ED with stonesmay be young and repeatedly present in ED with stonesCurrent practice trends will include an expanded role for US Current practice trends will include an expanded role for US based on patient history/age and urinalysisbased on patient history/age and urinalysis

Following 3 CT images show a right UVJ stone Following 3 CT images show a right UVJ stone causing right hydronephrosis and hydroueretercausing right hydronephrosis and hydrouereterStudy done with “Yale protocol,” using no oral or Study done with “Yale protocol,” using no oral or IV contrast (no oral contrast because not looking IV contrast (no oral contrast because not looking for intraperitoneal pathology, no IV contrast since for intraperitoneal pathology, no IV contrast since virtually all ureteral stones will be opaque enough virtually all ureteral stones will be opaque enough to be visible and contrast might actually obscure to be visible and contrast might actually obscure stone)stone)Stone is at UVJ where most small stones hold up Stone is at UVJ where most small stones hold up (most stones are small), while large stones hold (most stones are small), while large stones hold up at UPJup at UPJ

80 y.o. male with severe abd. pain, 80 y.o. male with severe abd. pain, hypotension, and a pulsatile abd. hypotension, and a pulsatile abd.

massmass

The story suggests a ruptured abdominal aortic aneurysm The story suggests a ruptured abdominal aortic aneurysm with a mortality of as much as 50%, so patient needs to go to with a mortality of as much as 50%, so patient needs to go to OR (don’t send unstable patients to radiology)OR (don’t send unstable patients to radiology)In ED, a quick US could be done, and would usually be able In ED, a quick US could be done, and would usually be able to show an AAA if present, but US unreliable in ruling out the to show an AAA if present, but US unreliable in ruling out the other critical question of rupture/bleedother critical question of rupture/bleedIf patient is stable, not hypotensive, CT is indicatedIf patient is stable, not hypotensive, CT is indicated– No oral contrast is needed: pathology is not intraperitonealNo oral contrast is needed: pathology is not intraperitoneal– No IV contrast is needed: the 2 key pathologies (AAA, No IV contrast is needed: the 2 key pathologies (AAA,

retroperitoneal bleed) are both visible because they are retroperitoneal bleed) are both visible because they are contrasted against retroperitoneal fatcontrasted against retroperitoneal fat

– If IV contrast were given in this case, the bleed may not light up If IV contrast were given in this case, the bleed may not light up at all because it is a clot without blood flow; only bleeding that at all because it is a clot without blood flow; only bleeding that occurred in the 60 sec between contrast injection and scanning occurred in the 60 sec between contrast injection and scanning would light upwould light up

The following 3 CT images show a large The following 3 CT images show a large ruptured AAA with retroperitoneal bleedruptured AAA with retroperitoneal bleed

Note that this is a completely Note that this is a completely retroperitoneal bleed because the kidney retroperitoneal bleed because the kidney is displaced, and the descending colon is is displaced, and the descending colon is elevated anteriorlyelevated anteriorly

The following 4 CT images of a trauma case show a lacerated The following 4 CT images of a trauma case show a lacerated spleen and left kidney, with associated minimal intraperitoneal spleen and left kidney, with associated minimal intraperitoneal bleed and large retroperitoneal bleedbleed and large retroperitoneal bleedThe case is shown to emphasize the importance of IV The case is shown to emphasize the importance of IV contrast administration to show solid organ pathology (blood contrast administration to show solid organ pathology (blood in splenic lacerations in this case, but also for tumor, e.g.)in splenic lacerations in this case, but also for tumor, e.g.)If IV contrast had not been given in this case, the splenic If IV contrast had not been given in this case, the splenic lacerations may have been hard to seelacerations may have been hard to seeNote that IV contrast does not light up the blood in the Note that IV contrast does not light up the blood in the lacerations (that’s clotted blood without flow), but it does light lacerations (that’s clotted blood without flow), but it does light up the normally perfused splenic tissue to produce a density up the normally perfused splenic tissue to produce a density difference (contrast)difference (contrast)