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CASE REPORTS FROMMULTISLICE CT SOMATOM Sensation 16

Contents

SOMATOMSESSIONS

Issue no.12


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SOMATOM SESSIONS 12

This is the twelfth issue of Siemens SOMATOM Sessions.In this issue, we would like to share with you the ex-citements of CT volume imaging with the SOMATOMSensation 16. We present you with clinical case reportsfrom our clinical partners.

To order copies of the past issue or submit your registrationfor receiving future issues, please visit our Web site at:http://www.siemensmedical.com/somatomsessions

As always, we appreciate your suggestions and comments.

Xiaoyan Chen, M.D., MBAEditor of SOMATOM Sessions

The information in this document contains general descriptions of the tech-nical options available, which do not always have to be present in individualcases. The required features should therefore be specified in each individualcase at the time of closing the contract.

The information presented in the case report is for illustration only and is notintended to be relied upon by the reader for instruction as to the practice ofmedicine. Any health care practitioner reading this information is remindedthat they must use their own learning,training and expertise in dealing withtheir individual patients. This material does not substitute for that duty and isnot intended by Siemens Medical Solutions Inc., to be used for any purposein that regard.

The drugs and doses mentioned herein were specified to the best of ourknowledge. We assume no responsibility whatsover for the correctness ofthis information.Variations may prove necessary for individual patients.The treating physician bears the sole responsibility for all of the parametersselected.

From the Editor


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CASE 1:CT Angiography for Intracranial Aneurysm Diagnosis of Anterior CommunicatingArtery Aneurysm Page 4

CASE 2:Incidental Diagnosis of Early Stage LungCancer with Suspected PE Page 6

CASE 3:Selective Celiomesenteric Stenosis Visual-isation by Contrast Enhanced 16-slice CT Page 10

CASE 4:Incidental Diagnosis of an AberrantRight Subclavian Artery in a Case of IsolatedPeripheral Pulmonary Embolism Page 14

CASE 5:Acute Rupture of an Abdominal AorticAneurysm after Aortic Stent Fracture Page 17

CASE 6:Direct Aortic Origin of Left Gastric ArteryDiagnosed Incidentally During Pre-operativeEvaluation for Hepatic Arterial InfusionPump Placement. Page 20

CASE 7:Liver Metasteses Page 22

CASE 8:Mobile Distal Ureteral Stone Page 24

CASE 9:Multiple Pathology Page 26

High Resolution Multislice CTin Critical Ill Patients Page 28

CASE 10:Adult Respirators Distress Syndrome (ARDS) Page 28

CASE 11:AIDS-related Non-Hodgkins Lymphoma Page 30

CASE 12:Three-phase Renal CT Diagnosis of RenalPelvic Transitional Cell Carcinoma Page 32

Contents


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SOMATOM SESSIONS 12

HISTORY

The patient is a 44-year-old female with past medicalhistory of a stroke and hypertension, with outside MRshowing suspicion of aneurysm. She has complaints of lefthemibody numbness, which is constant since the paststroke.

DIAGNOSIS AND COMMENTS

CT angiography show a lobulated aneurysm arising offof the left A-1 /A2 junction. This measures 13 mm in trans-verse diameter. The neck of the aneurysm is broad basedand extends towards the anterior communicating arteryto the right. However, the bulk of the aneurysm anddome project laterally to the left. There is a hypoplasticleft A-1 segment. The right A-1 segment is widely patent.Both carotid siphons widely patent and unremarkable inappearance.Two critical surgical factors are defined by the CT angio-gram: 1) the neck is broad based, making coil embolizationless favorable, and 2) that while the bulk of the aneurysmprojects to the left, the neck is most accessible from theright. The right approach is also more favorable since thenondominant hemisphere would undergo surgical mani-pulation.The patient subsequently underwent a right frontotem-

poral craniotomy and microsurgical clipping of anteriorcommunicating artery aneurysm.

Case 1: CT Angiography for Intracranial Aneurysm Diagnosis of Anterior Communicating Artery Aneurysm

EXAMINATION PROTOCOLS

Scanner SOMATOM Sensation 16

Scan region HeadLength 10 cmSlice collimation 16x 0.75 mmScan direction Cranio-caudalRotation time 0.5 skV 120Eff. mAs 200Kernel H20 smooth

Scan time 7.5 sSlice width 1 mmReconstruction Increment 0.5 mm

Contrast non ionic contrast media(300 mg iodine per ml)

Volume 100 mlFlow rate 4 ml/ sDelay Bolus tracking with CARE Bolus

Postprocessing Thin MIP and VRT on the Wizard


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[ 1 ] Oblique volume rendering with high opacificationshows aneurysm with broad neck at the A1/A2 junction,

and hypoplastic left A1 segment.

[ 2 ] Lateral VRT with high opacificaton shows relation-ship of skull base to the aneurysm.

[ 3 ] Base view VRT shows aneurysm projecting to the left. [ 4 ] Axial CT base data image through aneurysm.

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HISTORY

A 62-year-old male patient with a history of heavy smokingfor many years (more than 30 pack-years) now suffers fromcoughing and shortness of breath. His blood testresults show slightly elevated d-dimer. He was referredto the radiology department with suspected pulmonaryembolism.


Even though there was no filling defect found within thepulmonary vessels, the CT was able to delineate even thevery peripheral pulmonary arteries [Fig. 1] . The imagesreconstructed with high resolution kernel did not show anysign of chronic PE such as mosaic pattern perfusion[Fig. 2] . The diameter of the right ventricle and the mainpulmonary arteries were within a normal range, and therewas no signs of increased right heart load. Pulmonaryembolism as a reason for the symptoms could be ruled out.

However, a solitary pulmonary nodule in the right lowerlobe was shown without signs of benignancy [Fig. 3] .Having the raw data of the CT scan still available on thescanner, an additional retrospective reconstruction wasdone with the following parameters: Kernel: B50f, slicewidth: 0.75mm, increment 0.6mm. These images wereloaded into LungCARE program to perform an accurate vol-ume measurement [Fig. 4] .The patient was asked to come back for a follow-up scan in3 months. The follow-up exam revealed a typical growthpattern of lung cancer. The patient was refered to the tho-racic surgery department, and the nodule was fully re-

sected. The pathology diagnosis proved the lesion tobe a stage 1 lung cancer. The patient is doing well afterthe surgery.

The reason for the coughing, shortness of breath and theelevated d-dimer was never discovered. The symptomsvanished a few hours after the first CT scan.

Case 2: Incidental Diagnosis of Early StageLung Cancer with Suspected PE



Scan Area LungScan length 30 cmScan time 10 sScan direction caudocranialKV 120Effective mAs 100Rotation time 0.5 s

Slice collimation 16x0.75 mmSlice width 1st: 0.75 mm

2nd: 3 mm3rd: 0.75 mm

Table feed / rotation 15 mmReconstruction increment 1st: 0.6 mm

2nd: 3 mm3rd: 20 mm

Kernel 1st: B 20 f 2nd: B 20 f 3rd: B 70 f


Volume 120 mlFlow rate 5 ml/ sStart delay Test Bolus

(20 ml contrast + 50 mlNacl chasing, ROI positioned atthe main pulmonary artery)+ 4 s

Postprocessing MPRs and MIPs on the Wizard,VRT and Volume measurementwith LungCARE


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[ 1 ] MIP images show no filling defect within thepulmonary vessels while being able to delineate eventhe very peripheral pulmonary arteries.

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[ 2 ] Image reconstructed with high resolution kernelshows no signs of chronic PE such as mosaic patternperfusion.

[ 3 ] A solitary pulmonary nodule found in the rightlower lobe shows no signs of benignancy (first scan).

[ 4 ] Follow up CT exam in 3 months axial imagepresents the slightly changed nodule which is connectedto the vessel.

[ 5 ] Follow up CT exam in 3 months Volumetricmeasurement performed with LungCARE program showsthe growth of the nodule (260.68 mm 3 as comparedto 163.23 mm 3 from the first scan).

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SOMATOM SESSIONS 12


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[ 6 ] Screenshot of LungCARE program shows the projected position of the marker and the volumetric measurement (163.23 mm 3 ) of the solidary nodule (first scan).

CASE 2: Incidental Diagnosis of Early StageLung Cancer with Suspected PE

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SOMATOM SESSIONS 12

HISTORY

A 72-year-old caucasian female smoker was admitted forrecurrent episodes of postprandial painful abdominalcramps and colic. Prior to admission she had weight lossby unknown cause. Her medical history included hyper-tension, rheumatic arthritis, carotid stenosis and stroke;previous surgeries included cholecystectomy, carotidendarterectomy and inguinal hernia repair. She was takingSulfasalazine and Methotrexate for her history of activerheumatic arthritis, hypertension was controlled withQuinapril and Bisoprolol, and high cholesterol levels werecontrolled with Simvastatine. Her family history was indica-tive for vascular diseases.At physical examination, paraumbilical and abdominalaorta murmurs on auscultation were noticed, all peripheralpulses were easily palpable and bilaterally equal. No abnor-mality was detected by sonography of the upper abdomen.The patient was referred to the radiology department withhigh clinical suspicion of chronic intestinal ischemia.A contrast-enhanced Multislice Computed Tomography

(MSCT) scan was performed, that provided high qualityimages on which vascular mesenteric lesions could beassessed. Splanchnic vessels were also visualised by digitalsubstraction angiography (DSA). Stenotic lesions of the ori-gin and lower part of the superior mesenteric artery (SMA)were visible on both the angiogram and the MSCT scan[Fig. 1, 3B, 4B, 5] . Extensive calcifications in lower parts ofSMA were only visualised by MSCT[Fig. 4B, 5] . A normalceliac trunk was visulized with DSA probably due to thepositioning of the catheter just prior to theorigin of the stenosis [Fig. 2] . With MSCT calcifications werevisible in the celiac trunk; the presence of calcified

lesions complicated the evaluation of stenosis [Fig. 3A] .


The celiac and superior mesenteric arteries are the main-stay of vascular supply to the abdominal viscera. They sup-ply the hepatobiliary system, pancreas, spleen, omentum,and most of the bowel, except the esophagus, the distalcolon and rectum beyond the transverse colon. Insufficientintestinal blood flow can cause postprandial abdominalpain and weight loss1. The angiographic criteria of chronicmesenteric ischemia consist of the presence of significant

stenosis or obliteration of 2 of the 3 main gastrointestinalarteries2.For the diagnostic evaluation of a patient referred with clin-ical suspicion of chronic intestinal ischemia several imagingtechniques are available3 4. DSA is still considered to be thegold standard in diagnosing splanchnic vessel disease.However, using modern MSCT scanners the abdominalaorta, the origins of the splanchnic arteries, their centralparts, and first branches can be visualised with diagnosticquality. Advantages of MSCT angiography include minimalinvasiveness, short examination time and the opportunity

Case 3: Selective Celiomesenteric StenosisVisualisation by Contrast Enhanced 16-slice CT



KV 120mAs 140Slice collimation 16x0.75 mmSlice width 2.0 mmField of View 38.0 cmReconstruction increment 1.0 mmRotation time 0.5 s

Feed per rotation 15 mmTotal acquisition time 14.4 sReconstruction algorithm B 30 f Total number of images 409

Contrast Omnipaque 300 mg/l

Injection volume 120 mlInjection rate 3.5 ml/sStart delay 24 s

Postprocessing MPR, MIP and VRT


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[ 2 ] DSA frontal (A) and lateral (B) visualisations show normal aspect of the celiac trunk.

[ 1 ] DSA frontal (A) and lateral (B) visualisations demonstrate two stenotic lesions in the SMA.

A B

A B


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SOMATOM SESSIONS 12

[ 3A ] Axial MPR image shows calcification of theceliac trunk (arrow).

[ 3B ] Axial MPR image shows the soft plaques and thecalcification which cause the stenosis of the SMA.

to rule out other causes of abdominal pain. In patients withchronic disorders or suspected alteration of mesentericblood flow the diagnostic value of a non-invasive diagnos-tic test as MSCT is comparable to DSA5. Suspicion of mesen-teric ischemia based upon careful evaluation of patienthistory and clinical situation should be an early indication

for CT. Only in critically ill patients DSA is the preferredmethod because total procedure time (acquisition, imageprocessing and evaluation) is shorter and immediate inter-vention is possible. In conclusion, visualisation and evalua-tion of the splanchnic vessels by MSCT angiography inpatients with suspicion of chronic intestinal ischemia ispromising.

REFERENCES1 Rogers DM, Thompson JE, Garret WV et al: Mesenteric vascularproblems: a 26-year experience. Ann Surg 1982; 195: 554-565

2 Clark RA, Gallant TE: Acute mesenteric ischemia: angiographicspectrum. Am J Roentgenol 1984; 142(3): 555-62

3 Prez C, Llauger J, Puig J, Palmer J: Computed tomographic findingsin bowel ischemia. Gastrointest Radiol 1989; 14: 241-245

4 Franquet T, Bescos JM, Reparaz B: Non-invasive methods in thediagnosis of isolated superior mesenteric vein thrombosis:US and CT. Gastrointest Radiol 1989; 14: 321-325

5 Klein HM, Lensing R, Klosterhalfen B, Tons C, Gunther RW: Diagnosticimaging of mesenteric infarction. Radiology 1995; 197(1): 79-82

A B


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CASE 3: Selective Celiomesenteric StenosisVisualisation by Contrast Enhanced 16-slice CT

[ 4A ] Curved line denotes the curvature of the plane infigure 4B.

[ 4B ] Curved MPR image demonstrates the extentedpart of the SMA with extensive calcification.

A B

[ 5 ] VRT imagesdemonstrate clearly the severe calcifica-

tions and the stenosisof the SMA.


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HISTORY

A 72-year-old man presented with acute right sided pleu-ritic chest pain. His past medical history revealed a 90%proximal stenosis in the left anterior descending coronaryartery treated by PTCA in 1996. The physical examinationwas unremarkable. The screening laboratory tests includ-ing hemogram, coagulation status and chemistry hadnormal results. The electrocardiogram showed a formerknown sinus bradycardia (53 bpm). The echocardiogramdemonstrated a left ventricular hypertrophy with pre-served overall function and without any regional wallmotion abnormalities. The ejection fraction was 60%. Theright ventricle was normal in size and function. Theposteroanterior and the lateral chest radiograph demon-strated a prominence of the right hilum and a mildcardiomegaly. There was no pleural effusion or pneumo-thorax. The lungs were clear. In order to exclude pul-monary embolism (PE) as the source of his symptoms a

CT scan of the chest on a 16-slice CT scanner was per-formed using a standard pulmonary embolism protocol.


The CT scan confirmed the diagnosis of acute pulmonaryembolism and revealed a filling defect in the periphery ofthe medial segment of the right lung base. There wasanother irregular filling defect in a medial subsegment ofthe right middle lobe. Another small filling defect was seenin a lingular branch. Filling defects were isolated to subseg-mental and smaller pulmonary arteries. No central fillingdefects were present. The lungs were clear with the excep-tion of a 2 mm nodular density in the periphery of theanterior segment of the right upper lobe. No other nodulardensities were identified. A mildly prominent lymph nodewas noted in the mediastinum in the subcarinal regionmeasuring 9 mm in the short axis.

Incidentally, the scan also revealed an aberrant right sub-clavian artery (ARSCA), also known as arteria lusoria (afterlusus naturae, freak of nature)1. This is a rare anomaly

of the aortic arch. Based on autopsy findings, the ARSCAhas a prevalence of 0.7% in the general population2.The ARSCA arises as the last branch of the aortic arch andtraverses the mediastinum from left to right, scalloping theoesophagus posteriorly. Abnormal involution or absence ofthe fourth right aortic arch during the embryonal stage,which normally forms the proximal part of the right sub-clavian artery is the cause for the aberrant course of thisartery3. Since the persisting right aortic arch forms the rootof the aberrant artery, the ARSCA often has a broad base(Kommerells diverticulum)4. The aberrant right subclavianartery is usually asymptomatic and, as in this case, only

strikes the clinician as an anatomic curiosity; however,sometimes dysphagia, dyspnea, coughing, stridor, recur-rent pneumonia, thoracic pain, or Horner syndrome maydevelop. When symptoms are intractable, surgical correc-tion should be considered58 . Importantly, the rare butpotentially lethal association of the ARSCA with congenitalheart defects or aneurysms must be considered.

Case 4: Incidental Diagnosis of an AberrantRight Subclavian Artery in a Case of Isolated PeripheralPulmonary Embolism



Scan Area Entire Thorax Scan length 25 cmScan time 7 sScan direction caudocranialkV 120

Effective mAs 200Rotation time 0.5 sSlice collimation 16x 0.75 mmSlice width 0.75 mmTable feed / rotation 18 mm

Contrast Ultravist (300 mg iodine per ml)

Volume 125 mlFlow rate 3.0 ml/ sStart delay CARE Bolus

Postprocessing Coronal and sagittal MPRs,MIPs and VRTs


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[ 1 ] Subsegmental pulmonary embolism in the rightmiddle lobe.

[ 3 ] Axial CT section at the level of the origin of the ARSC.

[ 2 ] Subsegmental pulmonary embolism in the rightlower lobe.

[ 4 ] Multiplanar reconstruction of the proximal part of the aberrant right subclavian artery traversing the midlinefrom left to right.

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SOMATOM SESSIONS 12

In this case, using 16-slice CT with submillimeter resolution,a diagnosis of subsegmental pulmonary embolism as thesource of the patients signs and symptoms could be estab-

lished within 7 seconds. Residual uncertainty concerningthe accuracy of CT for diagnosing central and peripheralpulmonary embolism should be finally overcome with theadvent of this technology9. As strikingly demonstrated inthis case, CT also allows reliably establishing importantalternative and additional diagnoses in patients with sus-pected PE, which may range from incidental congenitalvariants, such as here, to life threatening conditions (e.g.aortic dissection)10.

REFERENCES1 Bayford, D. (1794) An account of singular case of obstructed deglutition.Memoires Med Soc of London 2: 275-86

2 Molz, G., Burri, B. (1978) Aberrant subclavian artery (arteria lusoria):Sex differences in the prevalence of various forms of the malformations.Evaluation of1378 observations. Virch Arch A Pathol Anat Histol 380: 303-15

3 Janssen, M., M. G. Baggen, et al. (2000) Dysphagia lusoria:clinical aspects, manometric findings, diagnosis, and therapy.Am J Gastroenterol 95(6): 1411-6

4 Kommerell, B. (1936) Verlagerung des sophagus durch eine abnormverlaufende Arteria subclavia dextra (Arteria lusoria). Fortschr GebRoentgenstr Nuklearmed 54: 590-5

5 McNally, P. R. and K. M. Rak (1992) Dysphagia lusoria caused bypersistent right aortic arch with aberrant left subclavian artery anddiverticulum of Kommerell. Dig Dis Sci 37(1): 144-9

6 Stork, T., R. Gareis, et al. (2001) Aberrant right subclavian artery(arteria lusoria) as a rare cause of dysphagia and dyspnea in a 79-yearold women with right mediastinal and retrotracheal mass, and coexistingcoronary artery disease. Vasa 30(3): 225-8

7 Jebara, V. A., E. Arnaud-Crozat, et al. (1989). Aberrant right subclavianartery aneurysm: report of a case and review of the literature. Ann VascSurg 3(1): 68-73

8 Turkenburg, J. L., M. I. Versteegh, et al. (1994). Case report: aneurysmof an aberrant right subclavian artery diagnosed with MR imaging. ClinRadiol 49(11): 837-9.

9 Schoepf UJ, N. Holzknecht, et al. (2002). Subsegmental pulmonaryemboli: improved detection with thin-collimation multidetector-row spiralCT. Radiology (222): 483-90.

10 Schoepf, U. J., M. A. Kessler, et al. (2001). Multislice CT imaging ofpulmonary embolism. Eur Radiol (11): 2278-86.

[ 5 ] Multiplanar reconstruction of the ARSCA, scallopingthe oesophagus from posterior.

[ 6 ] Volume rendered visualization of the aortic arch andits major branches. The ARSCA has its origin distal to theleft carotid artery and the left subclavian artery andcrosses the midline posterior to the oesophagus.


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HISTORY

A 74-year-old male patient with known aortic diseasewas referred to computed tomography because of thesuspicion of a penetrating aortic aneurysm with acutehaemorrhage. The patient presented at the emergencydepartment with symptoms of abdominal pain with anacute onset 24 hours ago. Laboratory findings showed ahaemoglobin level of 10.5mg/ dl. Abdominal ultrasoundperformed by the surgeons revealed a huge abdominalaneurysm. The patient underwent aneurysm stentingsome months ago. In addition graft surgery with a iliac-iliaccross-over bypass had been performed. At arrival at theradiology department the patient was still in a stable con-dition.


The 16-slice CT angiography data set showed aneurysmaticdilation of the aorta at the level of the diaphragm. Within

the infrarenal abdominal aorta a stentgraft could be identi-fied extending into the left common iliac artery. In additionocclusion of the proximal right common iliac artery isshown with a cross-over bypass graft to the right iliacartery arising from the left external iliac artery[Fig. 1, 2, 3] .Surrounding the aortic stent an aneurysmal sac with amaximal diameter of 5.5 cm and wall calcifications can beidentified. The opacified lumen within the stent showed adiameter of approximately 1.8 cm. Arising at the posterioraspect of the stent in between the first and second stentstrut extravasating contrast material can be found ex-tending into the aneurysmal sac. In addition a rupture of

the aneurysmal sac is shown leading to a massive intra-abdominal and retroperitoneal haemorrhage [Fig. 4, 5] .The final diagnosis based on MSCT angiography is ruptureof an abdominal aneurysm after abdominal aortic stentfracture.The patient underwent immediate emergency surgerybut died after insertion of a ballon blocker due to haemor-rhagic shock.

Case 5: Acute Rupture of an Abdominal Aortic Aneurysm after Aortic Stent Fracture



Scan Area From diaphragm to kneeScan length 70.9 cmScan time 31 sScan direction CraniocaudalKV 120Effective mAs 200Rotation time 0.5 s

Slice collimation 16x0.75 mmSlice width 0.75 mmTable feed / rotation 12 mmPitch* Volume pitch 16, Pitch factor 1Reconstruction increment 0.7 mmKernel B 30 f


Volume 120 mlFlow rate 5 ml/sStart delay Test bolus (20 ml; 5 ml / s + NaCl):

time to peak (22 s) + 8 s = 30 s

Postprocessing STS MIP coronal and sagittal,VRT on InSpace (Leonardo)

* Volume pitch = table feed per rotation / single slice collimation;Pitch factor = table feed per rotation / collimation


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[ 1 ] Volume rendering (InSpace) shows aorto-iliac stentgraft (arrows) and left-to-right iliac cross over bypass(arrow heads) due to right common iliacocclusion.

[ 3 ] Screen shot of InSpace

[ 2 ] Volume rendering (InSpace) shows equidistant lower stent struts but extended distance between the first twostruts (arrow heads). The contrast extravasation can alsobe depicted (arrows).

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[ 4 ] Coronal (A) and axial (B) thin MIP views show the aneurysmal sac within the infrarenal aortasurrounding the stentgraft. The wall can be easily identified by calcifications (arrows).

At the right lateral aspect of the sac rupture (A, asteriks) with contrast extravasation into a largehematoma is shown (arrow heads).

[ 5 ] Coronal (A) and axial (B) MPR shows the extension of the hematoma in the pararenaland perirenal space (arrows). Hematoma is supplied by acute extravasation of blood and contrast(arrow heads) due to acute rupture of the abdominal aneurysm.

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CASE 5: Acute Rupture of an Abdominal Aortic Aneurysm after Aortic Stent Fracture

A B

A B


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DIAGNOSIS AND COMMENTS:

Mild atherosclerosis was present in the abdominal aorta.Multiple low attenuation lesions were present in the liver,which were consistent with colon cancer metastases. CTangiography of the mesenteric arteries revealed an inci-dental finding of the left gastric artery originating directlyfrom the aorta [Fig. 1] . The common hepatic and splenicarteries arose from the aorta as a common trunk (hepa-tolienal trunk) [Fig. 2, 3] . The left gastric artery had a dia-meter of 2 mm. The length and course of the arteries werenormal. This variation occurs rarely, with angiographicand autopsy studies reporting a prevalence ranging from0.5 6%1 5. The embryological theory for this variation isthat the normal longitudinal anastomosis between thefour roots of the omphalomesenteric artery fails to fullycomplete 56. The first root does not unite with the otherroots, and therefore develops separately into a left gastricartery arising directly from the aorta.

Knowledge of the origin of the left gastric artery is impor-tant for certain operations, particularly when dissectionof the perivascular lymph nodes is required. Left peripheraland hilar types of cholangiocarcinoma, as well as gastriccancers, have a higher incidence of metastasis to lymphnodes along the left gastric artery than for other ar-teries710. Furthermore, in patients with gastric bleeding,the left gastric artery supplies the bleeding site in approxi-mately 85% of cases11.In this case, 16-slice multislice computed tomography(MSCT) allowed for thin slice acquisition (0.75 mm),increased z-axis coverage, and a shorter scanning time.

These improvements allowed for superior spatial resolu-tion resulting in clearer depictions of fine vascular details.Three-dimensional reconstruction of the mesenteric arter-ies was considered helpful by the surgeon during pre-operative evaluation for hepatic arterial infusion pumpplacement. Nowadays, even the smallest branches of theabdominal vessels may be visualized in a rapid, non-inva-sive fashion using 16-slice MSCT angiography.

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SOMATOM SESSIONS 12

HISTORY

A 70-year-old female presented for pre-operative abdomi-nal arterial anatomy evaluation for placement of a hepaticarterial chemotherapy infusion pump. Her past medical his-tory was significant for colorectal cancer metastatic to theliver, status-post colon resection. CT angiography was per-formed using a 16-slice multislice CT.

Case 6: Direct Aortic Origin of Left Gastric Artery Diagnosed Incidentally During Pre-operative Evaluationfor Hepatic Arterial Infusion Pump Placement.



Scan Area T11 S1Scan length 29.7 cmScan time 10 sScan direction CaudocranialKV 120Effective mAs 157Rotation time 0.5 s

Slice collimation 16x 0.75 mmSlice width 0.75 mmTable feed / rotation 15 mmReconstruction increment 0.4 mmKernel B 30 f

Contrast Ultravist (300 mg iodine per ml)

Volume 125 mlFlow rate 4 ml/sStart delay 30 s

Postprocessing Coronal and sagittal MIP and VRT


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[ 1 ] Maximum-intensity-projection showing left gastricartery originating directly from the aorta.

[ 2 ] Volume rendered anterior-posterior visualization of the abdominal aorta and its major branches.

[ 3 ] Volume rendered anterior-posterior visualizationof the abdominal aorta, showing hepatolienal trunk anddirect aortic origin of the left gastric artery (arrow).

REFERENCES:1 Yildirim, M., H. Ozan, et al. (1998) Left gastric artery originating directlyfrom the aorta. Surg Radiol Anat. 20(4): 303-05.

2 Kiss F. (1926) ber einige Varietaten der Arteria hepatica und Arteriacystica. Z Anat Entw Gesch 81: 601-619.

3 Naidich J.B., T.P. Naidich, et al. (1978) The origin of the left gastric artery.Radiology 126: 623-626.

4 Eaton P.B. (1917) The coeliac axis. Anat Rec 13: 369.

5 Vandamme J.P. and J. Bonte. (1985) The branches of the celiac trunk.Acta Anat 122(2): 110-14.

6 Tandler J (1904) ber die Varietten der Arteria coeliaca und derenEntwickelung. Anat Hft. 25: 472-500.

7 Kosaka T., N. Ueshige, et al. (1999) Lymphatic routes of the stomachdemonstrated by gastric carcinomas with solitary lymph node metastasis.Surg Today. 29(8): 695-700.

8 Tsuji T., T. Hiraoka, et al. (2001) Lymphatic spreading pattern of intra-hepatic cholangiocarcinoma. Surgery. 129(4): 401-7.

9 Tsagareishvili A. (1959) Variants of the origin of the left gastric arteryand their practical significance in stomach resection. Vestn Khir Grekova.83: 104-07.

10 Sawai K., T. Azuma, et al (1984) Angiographic analysis of vascularanatomy in gastric cancer. Nippon Geka Gakkai Zasshi 85: 143-52.

11 Kelemouridis V., C.A. Athanasoulis, et al. (1983) Gastric bleeding sites:an angiographic study. Radiology. 149(3): 643-8.


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HISTORY

A 33 year old female presented with Cushings disease. Anultrasound was performed. This showed liver nodules,there was also a suspicion of an adrenal mass. CT wasrequested for Adrenal malignancy or Malignancywith ectopic ACTH secretion.

DIAGNOSIS AND COMMENTS:Contrast enhanced CT of the chest, abdomen and pelviswere performed.Below the diaphragm, there were numerous deposits in allsegments of the liver. A lesion in the head of pancreasobstructed the pancreatic duct, which is very dilated withatrophy of the rest of the pancreas. No para-aortic orpelvic lympadenopathy was seen. Spleen and Kidneyswere normal. Adrenals were both enlarged, consistentwith hypertrophy.Following the CT exam the patient was admitted for a

Liver biopsy. Histology showed metastatic neuroendocrinetumour. The patient was referred to Clinical Oncology.

Case 7: Liver Metasteses



Scan Area From dome of diaphragmto s. pubis

Scan length 42.3 cmScan time 10.24 sScan direction CraniocaudalkV 120Effective mAs 140, modulated to 114 with

CARE DoseRotation time 0.5 sSlice collimation 16x1.5 mmSlice width 2 mmTable feed / rotation 24 mmPitch Volume pitch 16, Pitch factor 1Reconstruction increment 1.5 mmKernel B 20 f Smooth

Contrast Iopamidol (300 mg iodine per ml)

Volume 100 mlFlow rate 3 ml/sStart delay 70 s

Postprocessing VRT with InSpace


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[ 1 ] Coronal VRT image using InSpace at the level of theporta hepatis. It demonstrates enlarged liver with metas-tases. The enlarged liver displaces right kidney and ele-vates the right hemi-diaphragm.

[ 2 ] Coronal VRT image using InSpace. It demonstratesthe enlarged liver with metastases. The enlarged liver displaces right kidney. Both adrenals are enlarged due toectopic ACTH.


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HISTORY

A 64-year-old female patient with hematuria and recurrentlower abdominal pain underwent abdominal X-ray imag-ing, ultrasonography and CT.

Case 8: Mobile Distal Ureteral Stone


A mobile distal ureteral stone could be detected in CT. Anunknown descensus of the bladder, as pitfall, lead to themissing of the stone in conventional R-ray imaging and inabdominal US. Transrectal ultrasound also revealed thefloating stone. In no modality hydronephrosis was visible.The chronic dilatation of the distal ureter permits a mobilityof the stone of up to 8 cm proximal during CT examination.Ureteroscopy was performed, whereas the stone couldbe caught with a Dormia-basket, desintegrated by laserlithotripsy and extracted successfully. The patient resolvedquickly.

[ 1 ] conventional radiographic image of the region of thedistal left ureter and the bladder demonstrates no sign of the stone (A). By choosing special setting, VRT image (B)from the non contrast enhanced CT data set permits clear depiction of the stone (arrow), even when overlaying withbone structures (os pubis).

[ 2 ] The stone was detected in transrectal ultrasound

(arrow, B) not in abdominal ultrasound (A).



Scan length 38 cmScan time 15,8 SScan direction craniocaudalkV 120Effective mAs 180Rotation time 0,5 sSlice collimation 16x 0,75 mmSlice width 1 mmTable feed / rotation 12 mmPitch Volume pitch 16, Pitch factor 1Reconstruction increment 0,7Kernel B 30 f


Volume 100 mlFlow rate 2 ml/sStart delay 80 s (venous phase)

Postprocessing VRT with InSpace

A B

A

B


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[ 4A ] This VRT setting better permits visualization of thestone in the distal left ureter.

[ 3B ] Rotated lateral VRT image projection with the stonedisplayed through the left foramen obturatum.

[ 4A+ 4B ] After bolus i.v.contrast administration and an 8 minutes delay, the kidneys, ureter and bladder can be visualized in VRT images. Compared to the non contrast data set, the stone is

displayed more proximal and clearly in the dilateded distal left ureter.

[ 3A ] The high resolution CT data set can easily bedisplayed in VRT in a Martius like projection allowing ananatomically non distorted view from cranial oblique inthe pelvis for better ureter stone detection.

[ 4B ] For clear exclusion of hydronephrosis thedemarcation of the renal calyces and renal pelvis issuperor in this VRT setting.

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A B

A B


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SOMATOM SESSIONS 12

HISTORY

A 42 year old man, currently undergoing treatment forNeuroendocrine tumuor, was referred for CT of the chestand abdomen.Chemotherapy had been completed. Unfortunately he hadbeen unable to attend for a post 6 cycle treatment CT. Bio-chemistry results indicated 5 Hydroxindole acetic acid (5HIAA) as rising. A recent chest X-ray demonstrated newlung changes and it was considered that these may repre-sent progressive hilar changes. In view of the new chestmass, CT was requested to determine whether second linechemotherapy should be employed.


An enhanced examination was performed with acquisitionduring arterial phase, to demonstrate hypervascularHepatic lesions.The CT examination demonstrated evidence of previous

left upper lobe surgery, Multiple small peripheral pul-monary metastases were shown. Below the diaphragm,multiple liver metastases were demonstrated, thoughthese were stable with reference to previous CT examina-tion. Multiple sclerotic bone metastase were notedthroughout the vertebral column. A single left renal nodulewas shown. The patient was referred back to the care ofoncology for follow up.Neuroendocrine tumours have a relatively good prognosiscompared with other tumours and may survive for manyyears. Use of Chemotheraputic agents has largely been dis-appointing, though some agents have had some effect.

Case 9: Multiple Pathology

REFERENCEHauser H, Wolf G, Uranus S et al. Neuroendocrine tumours in various organsystems in a ten year period. Eur J Surg Oncol 1995: 21: 142146.

Meeran K. Carciniod andother neuroendocrine tumours. Summer school2000. 1014 July 2000 UK.



Scan Area From Apices to Mid L4Scan length 39.6 cmScan time 8.0 sScan direction CraniocaudalkV 120Effective mAs 140 effective, Modulated to 99Rotation time 0.5 s

Slice collimation 16x1.5 mmSlice width 2 mmTable feed / rotation 28.5Pitch Volume pitch 19, Pitch factor 1.2Reconstruction increment 1.5 mmKernel B 20 F smooth

Contrast Iopamidol (300 mg iodine per ml)

Volume 100 mlFlow rate 4 ml/ sStart delay 25 s

Postprocessing VRT and MIP with InSpace


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[ 1 ] VRT image using InSpace demonstrates single leftrenal deposit and multiple sclerotic spinal deposits.

Also evidence of the previous upper lobe surgery is shown

with healed ribs.

[ 2 ] Coronal VRT image using InSpace shows arterialphase, superior mesenteric and hepatic artery, alsoneovascularity, with multiple tortuous vessels supplying

the Hepatic deposits.

[ 3 ] Coronal VRT image using InSpace demonstratesmultiple peripheral metastases. Of particular interest isthe small nodule sitting on apex of left hemi-diagphram.Such a lesion would be difficult if not impossible to detecton an axial slices, thus demonstrating the value of volumedata acquisition and of course volume post processingtechnique (InSpace).


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SOMATOM SESSIONS 12

Multislice spiral CT drastically reduces examinationtime compared to singleslice CT Scanners [Fig. 1] . Shortexamination times are of utmost importance in exam-ining critical ill patients, patients who are short ofbreath, on mechanical ventilation or uncooperative.The new generation of multislice CT scanners offersimultaneous acquisition of 16 sub-millimeter slices.

This represents a breakthrough on the way towardstrue isotropic resolution in clinical routine. Imagesin arbitrarily chosen planes in an image quality asthe original axial slices now can be achieved not onlyin cooperative patients in a relatively well physicalstatus but also in patients from intensive care units.

High Resolution CT in Critical Ill Patients

HISTORY

A 70-year-old patient was admitted to hospital with coughand fever. He had prior resection of the right upper lobebecause of lung cancer. Despite the use of intensive anti-biotic therapy the patients condition rapidly deterioratedand intubation and mechanical ventilation became neces-sary. He developed signs of ARDS over the following days.

Fig. 2 shows the portable radiograph, CT was performedthe same day [Fig. 3] .


CT revealed hilar and mediastinal lymphadenopathy and asolid mass in the right upper lung suggestive for tumorrecurrence. Bilateral airspace opacities, pleural and peri-cardial effusion as well as interstitial thickening and apneumothorax on the left side became evident.

Despite being on mechanical ventilation, high resolutionimaging of the lung is possible. This facilitates the inter-pretation of acute lung disease. CT is clearly superior indetecting inflammatory processes and complications likepneumothorax.

Case 10: Adult Respirators Distress Syndrome (ARDS)EXAMINATION PROTOCOLS


Region Thorax Scan length 360 mmSlice collimation 16x0.75 mmTable feet / rotation 18 mmPitch Volume pitch 24, Pitch factor 1.5Scan direction craniocaudalRotation time 0.5 sKV 140Eff. mAs 100 (with CARE Dose)Scan time 10 sReconstructed slice width 0.75 mmReconstruction increment 0.5 mmkernel B 40 / B 70


Total volume 80 mlInjection rate 3 ml/sStart delay 50 s

Postprocessing VRT and MIP with Inspace


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0

100

200

300

400 [mm]

1x 1 mm;RT 0,75 s

4x 1 mm;RT 0,5 s

16x0,75 mm;RT 0,5 s

Scantime 10 s; Pitch 1,5

5

5

5

[ 1 ] Comparison of volume coverage with different CT types. [ 2 ] Portable radiograph showsbilateral airspace opacities.

[ 3 ] MPR and VRT images show bilateral airspace consolidation and interstitial thickeningpredominantly in the dorsal parts of the lung. Images reconstructed with high resolution kerneldemonstrate subpleural lines and interlobular septal thickening on the right side, pneumothorax and honeycombing on the left.

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HISTORY

A 32-year-old patient with acquired immunodeficiency syn-drome presented with fever, lethargy, a decreased level ofconsciousness and shortness of breath. Chest radiographdemonstrated a huge effusion in the right hemithorax.Subsequently a CT scan of the thorax and abdomen wasperformed [Fig. 4] .


The CT scan showed enlarged axillary lymph nodes as wellas bihilar, mediastinal and retroperitoneal lymphaden-opathy. Thickening of the pleura with contrast enhance-ment and large pleural effusion is suggestive for pleuraempyema. Atelectasis and air space opacification isdemonstrated on the right side, nodules in an otherwiseclear left lung. Inhomogeneity of the liver and spleen is dueto early contrast phase. Percutaneous drainage of the rightpleural space revealed tuberculous empyema, analysis of

the CSF was also suggestive for TB meningitis. Non-Hodgkins lymphoma was diagnosed from lymph nodebiopsy.Within a scantime of 17 seconds the thorax and abdomen(length of range: 600 mm) was examined with sub-mil-limeter slice collimation allowing for isotropic resolution.MPR in coronal orientation provide an excellent overviewin just a couple of images. The short examination time iscrucial to achieve motion-free images in critical ill patients.If isotropic resolution is not required the examination timecan be further reduced if a 16 x 1.5 mm collimation is used.

Case 11: AIDS-related Non-Hodgkins Lymphoma



Region Thorax-AbdomenScan length 600 mmSlice collimation 16x0.75 mmTable feet / rotation 18 mmPitch Volume pitch 24, Pitch factor 1.5Scan direction craniocaudalRotation time 0.5 s

KV 120Eff. mAs 140 ( with CARE Dose)Scan time 17 s

Reconstruction

Reconstructed slice width 0.75 mmReconstruction increment 0.5 mmkernel B 40 / B 70c

Contrast material non ionic contrast media(300 mg iodine per ml)

Total volume 120 mlInjection rate 3 ml/sStart delay 30 s


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[ 4 ] MPR image reconstructed with high resolution kernel (A, B) demonstrate right sided pleuraleffusion and the atelectasis and bilateral pulmonary nodules.MPR of thorax-abdomen scan (C) shows right sided empyema and lymph node conglomerates.

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A C

B


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HISTORY

68 year old male presenting with hematuria.

All scans phases were scanned with 0.75 mm collimation,pitch 16, at 120 kVp, 130 effective mAs, and 0.5 s scan time.A non-contrast scan is done to localize the kidneys, assess

for calcifications and allow for determination of enhance-ment following IV contrast. A test injection with 20 ml ofcontrast is used to determine the delay time for a vascularphase exam. Contrast is injected at 4 ml/s and imagesobtained over the upper abdomen every 2 seconds begin-ning at 20 seconds for 40 seconds. Time to peak enhance-ment of the upper abdominal aorta is calculated. Thevascular phase scan is performed using this delay timeplus 5 seconds for error and to allow venous filling. Thisscan includes the upper abdominal aorta through the iliacarteries. Then, a parenchymal phase scan was performed

of the entire abdomen and pelvis; the delay time from thestart of the contrast injection to the beginning of theparenchymal phase scan was approximately 120 s.

All scan phases were reconstructed at standard field ofview, B20 kernel, with a diagnostic set of images with 5 mmslice thickness and 2.5 mm reconstruction interval. Theseimages were for diagnostic review on the MagicView 1000.A second set of 1 mm slice thick images with an 0.8 mmreconstruction interval were also created, for use in 2- and3-dimensional reconstructions. The reconstructions weredone on the Wizard or Leonardo workstations. Oral con-trast was not administered as it can interfere with the 2-and 3-D renderings.

Case 12: Three-phase Renal CT Diagnosisof Renal Pelvic Transitional Cell Carcinoma



Scan region Abdomen and PelvisLength 3040 cmSlice collimation 16x 0.75 mmScan CraniocaudalRotation time 0.5 skV 120Eff. mAs 130Kernel B20 smoothScan time 12.517 sSlice width 3 mmIncrement 2.5 mm

Post-ProcessingReconstruction Image Set

Slice width 1 mmIncrement 0.8 mm

Postprocessing Leonardo Workstation

Thin MIP Coronal obliques orientedparallel to the kidneys

VRT Inspace

A


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[ 1 ] (A) Unenhanced, (B) vascular phase, and (C)Nephrographic phase axial CT images show a 2.1x1.5 cmenhancing mass (arrow) within the right renal pelvis,

surrounded anteriorly by excreted contrast.

[ 2 ] (A) Oblique coronal and (B) sagittal multiplanar reformations show the location of this mass within therenal pelvis.

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B C

A B


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[ 3 ] Volume rendering (using InSpace) from the nephro-graphic phase scan also gives a 3-dimensional appear-ance to the tumor showing it in relationship to the proxi-mal right ureter.

[ 4 ] Volume rendering (using InSpace) from the vascular phase scan shows two right renal arteries (A) includingplus an early branch from the main renal artery anda single right renal vein (B). The location and relativeposition to each other are important for surgical planningpurposes.

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A 2.1x1.5 cm enhancing mass is seen in the right renal

pelvis. The mass demonstrates no calcification on the un-enhanced images, and enhancement from 44 Hounsfieldunits pre-contrast to 83 Hounsfield units on the nephro-graphic phase following contrast [Fig. 1] . No renalparenchymal mass, lympha-denopathy, or vascular inva-sion is identified. Coronal oblique and sagittal images,and volume rendering [Fig. 2, 3] demonstrate the tumorposterior within the renal pelvis but invading and nar-rowing the pelvis rather than a polypoid mass as suspectedby the axial images. Therefore this tumor was not amen-able to percutaneous or endoscopic resection, and thestandard surgical treatment of nephroureterectomy wasoffered. The vascular phase can be also used to render therenal vessels for surgical planning[Fig. 4] .Diagnosis: Transitional cell carcinoma of the right renalpelvis.Treatment: This patient subsequently underwent success-ful laparoscopic nephroureterectomy.

A B


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THIS ISSUES AUTHORS

Case 1 Jeffrey S. Ross, M.D.

Section of NeuroradiologyDivision of RadiologyCleveland Clinic FoundationDesk L-109500 Euclid Ave.Cleveland, OH 44195USA

Case 2Peter Herzog, MDDepartment ofDiagnostic RadiologyKlinikum GrohadernMarchionistrasse 1581377 Munich,Germany

Case 3D.B. Rouw, P.M.A. van Ooijen, W.G.J. Tukker, J. Dorgelo, R. Vliegenthart, M. OudkerkDept. of Radiology,Groningen University Hospital,Groningen,The Netherlands

Case 4Patrick Ingelfinger, Marco Das,

Ann McGinnis, U. Joseph SchoepfDepartment of Radiology Brighamand Womens HospitalHarvard Medical School75 Francis StreetBoston, MA 02115USA

Case 5Bernd J. Wintersperger, MDDepartment of Diagnostic RadiologyKlinikum GrohadernMarchionistrasse 1581377 Munich,Germany

Case 6Vito Cantisani, Babak N. Kalantari, Koenraad J. Mortele, Jean M. Allen, U. Joseph Schoepf,Stuart G. Silverman, Elisa Pagliara, Pablo R. RosDepartment of Radiology,Brigham & Womens Hospital,Harvard Medical School,Boston, Massachusetts, USA

Case 7/Case 9Prof. Adrian DixonDepartment of RadiologyAddenbrookes HospitalHills rd, Cambridge.

CB2 2QQ.UK

Case 8Gudrun Feuchtner, Ferdinand Frauscher, Alexan-

der v. SmekalDepartment of Radiodiagnostics, Radiology II,University HospitalAnichstrasse 35A 6020 InnsbruckAustria

Case 10/ Case 11Dr. Michael LellInstitut fr Diagnostische Radiologie,Universitt ErlangenMaximiliansplatz 1,91054 Erlangen,Germany

Case 12Brian R Herts, M.D.Section of Abdominal ImagingDivision of RadiologyCleveland Clinic FoundationDesk Hb-69500 Euclid Ave.Cleveland, OH 44195USA

IMPRESSUM

Published by

CT MarketingSiemens AGMedical SolutionsSiemensstrasse 191301 Forchheim, Germany

International Distribution

Xiaoyan Chen, M.D., MBACT Concepts

Siemens AG, Medical SolutionsSiemensstrasse 191301 Forchheim, GermanyPhone +49-9191-18-9652Fax +49-9191-18-9996eMail [email protected]

Anil GuptaCT Marketing

Siemens AG, Medical SolutionsSiemensstrasse 191301 Forchheim, GermanyPhone +49-9191-18-8121Fax +49-9191-18-9998eMail [email protected]

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SOMATOM SESSIONS 12

Somatom Sessions 12

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