J Comput Assist Tomogr

Three-dimensional imaging of the stomach by spiral CT.

Lee DH.
Department of Diagnostic Radiology, Kyung Hee University Hospital, Seoul, Korea.
Three-dimensional spiral CT is a new imaging modality, 3D-CT of the gastrointestinal tract, so-called "virtual endoscopy," has a potential for widespread use in the diagnosis of pathologic conditions of the bowel. Clinical applications of 3D-CT in the stomach include the evaluation of early gastric carcinoma, advanced gastric carcinoma, leiomyoma, lymphoma, and benign ulcer. The main advantage of 3D-CT over axial CT of the stomach is its accurate display of gastric lesions as shown by gastroscopy. Virtual gastroscopy has the potential of replacing barium studies. Moreover, combined axial CT and 3D-CT imaging using spiral CT make it possible to accurately diagnose gastric lesions.

Dual-phase helical CT of nonfunctioning islet cell tumors.

Stafford Johnson DB. Francis IR. Eckhauser FE. Knol JA. Chang AE.
Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030, USA.
PURPOSE: The aim of this study was to evaluate the utility of dual-phase imaging in the assessment of nonfunctioning islet cell tumors (NFITs). METHOD: Six patients with histologically and biochemically proven NFIT were evaluated by arterial and portal venous dual-phase helical CT. Scan delay was 20 s for the arterial phase and 70 s for the portal phase. Each phase was assessed by consensus reading and specifically evaluated for tumor conspicuity, hepatic metastases, vascular encasement by tumor, and presence of lymphadenopathy. RESULTS: Overall, tumor conspicuity was greater in the arterial phase (5/6) than in the portal venous phase (1/6) with a mean tumor/normal pancreas attenuation difference of 31.8 HU in the arterial phase compared with 19.2 HU in the portal venous phase. The arterial phase detected a total of 17 liver metastases compared with 9 seen in the portal phase. Lymph node enlargement was noted in three patients, which, although visible in both phases, was more easily discernible in the arterial phase. Venous encasement by tumor was better evaluated on the delayed portal venous phase than the arterial phase. CONCLUSION: Dual-phase helical CT scanning leads to improvement in the detection and staging of NFITs.

Double phase CT arteriography of the whole liver in the evaluation of hepatic tumors.

Inoue E. Fujita M. Hosomi N. Sawai Y. Hashimoto T. Kuroda C. Nakano H. Sasaki Y. Ishiguro S.
Department of Diagnostic Radiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
PURPOSE: Our goal was to evaluate the contribution of double phase CT arteriography (CTA) of the whole liver to differentiate hepatic tumors from false-positive areas on CT during arterial portography (CTAP). METHODS: In 38 candidates for surgical resection of hepatic tumors, both CTAP and double phase CTA were performed. A total of 68 perfusion defects were identified at CTAP. Of 68 perfusion defects, 47 were found to represent hepatic tumors [hepatocellular carcinoma (HCC), n = 31; hepatic metastasis, n = 13; cholangiocarcinoma n = 2; focal nodular hyperplasia, n = 1]. The other 21 perfusion defects were defined as perfusion abnormalities in which focal hepatic masses had not been identified at surgery or pathologic analysis. The phase one CTA scanning started 12 s after the beginning of the injection of contrast material, and the phase two CTA scanning started 20 s after the end of the phase one CTA, with 60 ml of contrast agent (150 mg I/ml) injected at a rate of 2 ml/s. RESULTS: On phase one CTA, only 1 lesion in 31 HCCs showed rim enhancement and 26 HCCs (84%) had rim enhancement on phase two CTA. Twelve lesions (80%) of the hepatic metastases and cholangiocarcinomas had rim enhancement on phase one CTA and 11 lesions (73%) showed rim enhancement on phase two CTA. Twenty-one perfusion abnormalities on CTAP did not show rim enhancement on either phase one or phase two CTA. CONCLUSION: Double phase CT arteriography of the whole liver was useful to differentiate hepatic tumors from perfusion abnormalities on CTAP.

Gastrointestinal leiomyoma and leiomyosarcoma: CT differentiation.

Chun HJ. Byun JY. Chun KA. Rha SE. Jung SE. Lee JM. Shinn KS.
Department of Radiology, Catholic University Medical College, Kangnam St. Mary's Hospital, Seoul, Korea.
PURPOSE: Our goal was to evaluate CT efficacy in differentiating gastrointestinal leiomyoma and leiomyosarcoma. METHOD: We retrospectively reviewed CT scans of 45 patients (21 men, 24 women, mean age 55 years) with surgically proven gastrointestinal leiomyomas (n = 21) and leiomyosarcomas (n = 24) with respect to size, contour, enhancing pattern, mesenteric fat infiltration, calcification, ulceration, regional lymphadenopathy, direct invasion, distant metastasis, and growth pattern after visual inspection by two radiologists in agreement. On the basis of these CT features, subjective diagnosis was also categorized into three groups (Group I: probably benign, Group II: probably malignant, Group III: diagnostic malignant). The results were compared with the final histopathologic diagnosis. RESULTS: In addition to the features of direct invasion and distant metastasis suggesting diagnostic malignancy, the CT features favoring malignancy with statistical significance included larger size (> 5 cm), lobulated contour, heterogeneous enhancement, mesenteric fat infiltration, ulceration, regional lymphadenopathy, and exophytic growth pattern (p < 0.005). However, calcification was not significant in differentiating the two entities (p = 0.25163). A subjective analysis revealed 89% sensitivity, 85% specificity, and 87% accuracy for diagnosis of leiomyosarcoma. CONCLUSION: CT features are useful in differentiating leiomyoma and leiomyosarcoma in gastrointestinal tract.

Staging of invasive cervical carcinoma and of pelvic lymph nodes by high resolution MRI with a phased-array coil in comparison with pathological findings.

Hawighorst H. Schoenberg SO. Knapstein PG. Knopp MV. Schaeffer U. Essig M. van Kaick G.
Department of Radiological Diagnostics and Therapy, German Cancer Research Center, Heidelberg, Germany.
PURPOSE: Our goal was to stage invasive cervical carcinoma (pT1b-pT4a) and pelvic lymph nodes by high resolution MRI with a circularly polarized (cp) phased-array coil in correlation with the whole-mount specimen and the histopathological findings. METHOD: Thirty-three patients (20-68 years old; mean age 55 years) with biopsy-proven primary cancer of the cervix were prospectively examined on a 1.5 T scanner by using a cp body phased-array coil. The MR protocol consisted of high resolution T2-weighted turbo-SE (TSE) and pre- and postcontrast T1-weighted SE (SE) sequences. Slice thickness was 5-7 mm with a pixel size of 0.3-0.4 mm2. All MRI findings were matched to the whole-mount specimens and the histopathological findings. RESULTS: Pathological stages evaluated were pT1b (n = 5), pT2b (n = 16), and pT4a (n = 12). The overall accuracy rates for tumor staging were 79% for high resolution T2-weighted TSE and 76% for postcontrast T1-weighted SE images. The accuracy for high resolution T2-weighted TSE images in determining parametrial infiltration, pelvic side wall, and bladder and rectal wall infiltration was 84, 87, and 87%, respectively. In prospective analysis of the 1.0 cm criterion for diagnosis of a positive pelvic lymph node, MRI had a 72% accuracy, a 68% sensitivity, and a 78% specificity. CONCLUSION: High resolution MRI with a cp body phased-array coil provides excellent and robust high resolution images in patients with invasive cervical carcinoma. However, accuracy, specificity, and sensitivity for staging invasive cervical carcinoma and pelvic lymph nodes with correlation to whole-mount specimens and histopathological findings did not improve compared with the results in the literature using a body coil with thicker slices and a lower spatial resolution.

Inflammatory pseudotumor of the liver: MRI with mangafodipir trisodium.

Materne R. Van Beers BE. Gigot JF. Horsmans Y. Lacrosse M. Pringot J.
Department of Radiology, Cliniques Universitaires Saint-Luc, Universite Catholique de Louvain, Brussels, Belgium.
Inflammatory pseudotumor of the liver is a rare benign mass that is often misdiagnosed as hepatocellular carcinoma at preoperative imaging. We report a case of inflammatory pseudotumor of the liver with special emphasis on the appearance at MRI after administration of mangafodipir trisodium. On T1-weighted images the lesion was slightly hypointense relative to the liver, and on T2-weighted images it was isointense with a hyperintense capsule. No tumor enhancement was seen on T1-weighted images after administration of mangafodipir trisodium. MRI with mangafodipir trisodium might help to distinguish inflammatory pseudotumor of the liver from hepatocellular carcinoma.

Dual-phase helical CT of locally invasive pancreatic adenocarcinoma.

Year 1998
Nino-Murcia M. Olcott EW. Jeffrey RB Jr.
Department of Radiology, Stanford University Medical Center, CA, USA.
Dual-phase helical CT permits imaging of the pancreas and the peripancreatic structures in the arterial dominant and portal venous phases of enhancement, providing information crucial in the assessment of the local extent of pancreatic adenocarcinoma. This essay reviews the dual-phase helical CT findings of local extension that preclude potentially curative surgery, including vascular involvement, ligamentous or mesenteric invasion, extension of the tumor to involve the stomach or duodenum, and invasion of adjacent solid organs.

Gastric cancer: evaluation of triphasic spiral CT and radiologic-pathologic correlation.

Year 1998
Takao M. Fukuda T. Iwanaga S. Hayashi K. Kusano H. Okudaira S.
Department of Radiology, Nagasaki University School of Medicine, Japan.
PURPOSE: The purpose of this study was to evaluate the utility of triphasic spiral CT with water-filling method in the preoperative T staging of gastric cancer. METHOD: We performed triphasic spiral CT in 108 patients with gastric cancer (53 with early and 55 with advanced gastric cancer). The CT findings were prospectively analyzed and correlated with the histopathologic findings. Spiral CT scans were assessed for the layered pattern of the normal gastric wall, the detectability of tumor, the enhancing pattern of the tumor, and the depth of tumor invasion. RESULTS: The layered pattern of the normal gastric wall was clearly demonstrated in the arterial-dominant or parenchymal phase. All 12 early cancers detected with spiral CT were most clearly depicted in the arterial-dominant or parenchymal phase. On the other hand, 15 (28%) of 54 advanced cancers were most clearly depicted in the equilibrium phase due to the gradual enhancement from the inner mucosal side of the tumor. Most of these tumors were scirrhous type tumor containing abundant fibrous tissue stroma. The accuracy of spiral CT for tumor detection and T staging was 98 and 82%, respectively, in advanced gastric cancer and 23 and 15%, respectively, in early gastric cancer. CONCLUSION: Spiral CT with triphasic scan technique improved the accuracy of estimating the depth of tumor invasion in advanced gastric cancer.

CT appearance of sclerosing peritonitis in patients on chronic ambulatory peritoneal dialysis.

Year 1998
Stafford-Johnson DB. Wilson TE. Francis IR. Swartz R.
Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030, USA.
PURPOSE: The purpose of this study was to describe the CT appearances of sclerosing peritonitis (SP) in patients on chronic ambulatory peritoneal dialysis (CAPD) and to compare these findings with the CT appearances in a control group of CAPD patients who did not develop SP. METHOD: The CT findings in 10 patients with SP were compared with those from a "control group" of 71 patients without SP who were on long-term CAPD and had also undergone at least one CT examination. Particular reference on CT examination was made to the appearance of the peritoneum and small bowel and the presence or absence of loculated fluid collections. RESULTS: Peritoneal abnormalities (calcification/thickening) were noted in 100%, loculated fluid collections in 90%, and small bowel abnormalities (tethering/dilatation) in 60% of the patients with SP. In the control group of patients, peritoneal abnormalities were noted in only 7%, loculated fluid collections in 15%, and small bowel dilatation in 5.7%. CONCLUSION: Peritoneal thickening, peritoneal calcification, loculated fluid collections, and tethering of the small bowel appear to be diagnostic of SP. In a small group of patients with follow-up CT scans, new, or progression of, CT findings correlated with the clinical severity of SP.

Lymphoepithelial cysts of the pancreas: demonstration of lipid component using CT and MRI.

Year 1998
Fukukura Y. Inoue H. Miyazono N. Kajiya Y. Fujiyoshi F. Yano T. Sakoda K. Tanaka S. Aiko T. Nakajo M.
Department of Radiology, Faculty of Medicine, Kagoshima University, Japan.
We present two cases of surgically proven lymphoepithelial cyst (LEC) of the pancreas that had a lipid component visualized by CT and MRI. Identification of this component in a pancreatic cystic lesion is a key to favor the diagnosis of LEC or splenic epidermoid cyst over other cystic lesions when the lesion is noted in an elderly patient.

Dual-phase helical CT of nonfunctioning islet cell tumors.

Year 1998
Stafford-Johnson DB. Francis IR. Eckhauser FE. Knol JA. Chang AE.
Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030, USA.
PURPOSE: The aim of this study was to evaluate the utility of dual-phase imaging in the assessment of nonfunctioning islet cell tumors (NFITs). METHOD: Six patients with histologically and biochemically proven NFIT were evaluated by arterial and portal venous dual-phase helical CT. Scan delay was 20 s for the arterial phase and 70 s for the portal phase. Each phase was assessed by consensus reading and specifically evaluated for tumor conspicuity, hepatic metastases, vascular encasement by tumor, and presence of lymphadenopathy. RESULTS: Overall, tumor conspicuity was greater in the arterial phase (5/6) than in the portal venous phase (1/6) with a mean tumor/normal pancreas attenuation difference of 31.8 HU in the arterial phase compared with 19.2 HU in the portal venous phase. The arterial phase detected a total of 17 liver metastases compared with 9 seen in the portal phase. Lymph node enlargement was noted in three patients, which, although visible in both phases, was more easily discernible in the arterial phase. Venous encasement by tumor was better evaluated on the delayed portal venous phase than the arterial phase. CONCLUSION: Dual-phase helical CT scanning leads to improvement in the detection and staging of NFITs.

Ionic versus nonionic contrast media: a prospective study of the effect of rapid bolus injection on nausea and anaphylactoid reactions.

Year 1998
Federle MP. Willis LL. Swanson DP.
University of Pittsburgh Medical Center, PA 15213, USA.
PURPOSE: The purpose of our study was to evaluate the effect of bolus infusion of contrast medium (ionic versus nonionic) on the incidence of nausea and anaphylactoid reactions. METHOD: We prospectively studied 1,827 patients who had bolus enhanced body CT scans and divided them into four groups: 725 patients received higher osmolality contrast medium (HOCM) at the slower bolus rate of 1-2.5 ml/s (SLOW-HOCM group); 650 patients were in the FAST-HOCM group and received the same ionic contrast medium at 4-5 ml/s; 250 patients received lower osmolality contrast medium (LOCM) at 1-2.5 ml/s, forming the SLOW-LOCM group; and 202 patients in the FAST-LOCM group got the same nonionic agent at 4-5 ml/s. RESULTS: We found no significant difference in the rate of nausea among the first three groups: SLOW-HOCM (3.9%), FAST-HOCM (4.9%), and SLOW-LOCM (3.2%). A statistically significant lower incidence of nausea (0.5%) was found in the FAST-LOCM group. Anaphylactoid reactions were significantly more common in both groups who received HOCM (8.3 and 9.1%) compared with the groups who received LOCM (2.0 and 2.5%). CONCLUSION: The bolus injection of warmed ionic contrast medium at a rate of 1-2.5 ml/s causes no significant increase in nausea compared with similar infusion rates of nonionic agents. For CT protocols that require infusion rates of 4-5 ml/s, the use of a nonionic agent is associated with a significantly reduced prevalence of nausea. The prevalence of anaphylactoid reactions is not affected by the rate of injection.

CT of neural plexus invasion in common bile duct carcinoma.

Year 1998
Fukuda T. Iwanaga S. Sakamoto I. Aso N. Nagaoki K. Hayashi K. Yamaguchi H. Okudaira S. Tomioka T. Okimoto T.
Department of Radiology, Nagasaki University School of Medicine, Japan.
PURPOSE: Our purpose was to analyze the CT findings of neural plexus invasion in common bile duct carcinoma. METHOD: We studied 16 patients with common bile duct carcinoma who underwent surgery. Of these, neural invasion was seen in 10 patients. CT findings were retrospectively reviewed and correlated with the surgical and pathological findings. RESULTS: Irregular masses adjacent to the medial aspect of the uncinate process were observed in 4 of 14 patients with distal common bile duct carcinoma. These lesions extended medially and showed contiguity with the superior mesenteric artery and/or celiac axis, corresponding to neural plexus invasion with desmoplastic change. Increased attenuation of the fat between the common bile duct and the proper hepatic artery was seen in two of two patients with proximal common bile duct carcinoma, associated with neural plexus invasion in the hepatoduodenal ligament. CONCLUSION: The location and spread of neural plexus invasion in common bile duct carcinoma are characteristic and can be diagnosed by CT.

MRI of fistula-in-ano: a comparison of endoanal coil with external phased array coil techniques.

Year 1998
deSouza NM. Gilderdale DJ. Coutts GA. Puni R. Steiner RE.
Robert Steiner Magnetic Resonance Unit, Royal Post-graduate Medical School, Hammersmith Hospital, London, England.
PURPOSE: The objective of our study was to compare MRI of fistulas-in-ano using an endoanal coil with that using a pelvic phased array coil and to assess the value of a combined approach by correlating the findings with those at surgery. METHOD: Twenty consecutive patients with clinical suspicion of perianal sepsis were studied using an endoanal coil immediately followed by a phased array coil. T1 weighted and STIR images in transverse and coronal planes were made with each coil and analysed by noting the presence and site of a collection and primary track, the position of any internal opening, and subcutaneous or supralevator extension. Operative findings were similarly recorded. RESULTS: Of 20 patients with suspected fistulas, 8 had simple fistulas, 8 had complex fistulas, and 4 had no current evidence of infection. The concordance between MR and surgery for identifying the presence and site of the collection, the primary track, and the internal opening in both simple and complex cases was superior using the endoanal coil as compared with the phased array. Both coils together reflected the findings of the endoanal coil used alone. However, for supralevator/subcutaneous extension, concordance was superior using the phased array compared with the endoanal coil, and a combined approach reflected the values of the phased array coil used alone. CONCLUSION: Endoanal MRI is highly sensitive in the delineation of fistulas-in-ano. In combination with phased array techniques, it provides valuable preoperative assessment in both simple and complex cases.

Breath-hold T2-weighted MRI of hepatic tumors: value of echo planar imaging with diffusion-sensitizing gradient.

Year 1998
Okada Y. Ohtomo K. Kiryu S. Sasaki Y.
Department of Radiology, University of Tokyo, Japan.
PURPOSE: The purpose of our study was to evaluate the efficacy of echo planar imaging (EPI) as a breath-holding T2-weighted technique for imaging focal hepatic lesions. METHOD: Forty-eight patients with focal hepatic lesions (9 metastases, 21 hepatocellular carcinomas, 1 cholangiocarcinoma, 16 hemangiomas, and 2 cysts) underwent single shot EPI with and without a small diffusion-sensitizing gradient (DSG) (beta values = 55 s/mm2) at 1.5 T. Comparison was made with breath-holding T2-weighted fast SE (FSE) sequences. RESULTS: Lesion-to-liver signal intensity ratio of EPI was significantly better than that of T2-weighted FSE (p < 0.05) in patients with metastasis. Use of DSG suppressed bright signals from vessels or periportal tissue, resulting in better conspicuity of small lesions. EPI with DSG visualized more metastatic deposits than T2-weighted FSE (p < 0.01). CONCLUSION: EPI with a small DSG is helpful for detection of small hepatic metastases.

Von Meyenburg complexes of the liver: imaging findings.

Year 1998
Luo TY. Itai Y. Eguchi N. Kurosaki Y. Onaya H. Ahmadi Y. Niitsu M. Tsunoda HS.
Department of Radiology, Clinical Medicine, University of Tsukuba, Japan.
PURPOSE: Our purpose was to present imaging findings of six cases proven or supposed to be von Meyenburg complexes (VMCs) with a basis of reviewing the pathologic literature and to describe imaging points for the diagnosis of typical VMC along with its differential diagnosis. METHOD: Six cases were diagnosed as VMC of the liver with imaging modalities (one had histopathologic proof). Both ultrasound (US) and CT were available for all cases, and MRI was used for three cases. Follow-up with US, CT and/or MRI was performed in five cases. RESULTS: US detected varying abnormalities of the livers in four cases. CT and MRI revealed multiple or numerous intrahepatic tiny (usually < 5 mm) cystoid lesions in all of the cases. The lesions were scattered throughout the livers, and some of them were located more frequently adjacent to the medium-sized portal veins than to the hepatic veins of similar size on CT. Moreover, some lesions were apparently located in the subcapsular areas (up to the hepatic capsules). They were usually irregular in shape and showed no enhancement but increased in number by approximately 80-150% after administration of intravenous contrast medium. The T2-weighted MR images and MR cholangiopancreatography showed the lesions to be much more apparent and to be more numerous than T1-weighted images did. Follow-up of five cases with imaging modalities did not show remarkable change of the lesions. CONCLUSION: Despite our limited experience, VMC lesions seem to show some CT and MR features different from those of other multiple small hepatic lesions. They presented as multiple or numerous intrahepatic tiny cystoid lesions usually with irregular contour, scattered throughout the liver up to the subcapsular areas, and were detected in far greater number by enhanced CT or T2-weighted MR images than by unenhanced CT or T1-weighted images. They showed no remarkable change on long term follow-up imaging. We propose that a diagnosis of typical VMC could be made after analyzing CT or MR images carefully with good understanding of its pathologic basis, but imaging follow-up is necessary in oncology patients.

Dynamic MR follow-up of small hepatocellular carcinoma after percutaneous ethanol injection therapy.

Year 1998
Fujita T. Honjo K. Ito K. Takano K. Koike S. Okazaki H. Matsumoto T. Matsunaga N.
Department of Radiology, Yamaguchi University School of Medicine, Japan.
For patients with small hepatocellular carcinomas (HCCs) treated by percutaneous ethanol injection (PEI) therapy, dynamic MRI has been performed to evaluate the therapeutic efficacy at our institute. In this pictorial essay, we illustrate the various dynamic MR findings of HCCs after PEI therapy, including complete necrosis, partial necrosis, local recurrence, and pathologic conditions such as arterioportal shunt and contractive changes of hepatic parenchyma. We also present the limitation of dynamic MRI in the evaluation of therapeutic effectiveness of PEI therapy.

Improved technique for pancreatic MRI: value of oblique fat suppression imaging with oral barium administration.

Year 1998
Helmberger T. Mergo PJ. Stoupis C. Torres GM. Burton SS. Ros PR.
Department of Radiology, University of Florida College of Medicine, Gainesville 32610, USA.
PURPOSE: Our goal was to determine the efficacy of a dedicated protocol for pancreatic MRI using fat suppression, oblique plane orientation, and barium as an oral contrast agent. METHOD: Fifty-two patients were enrolled in our study. In each patient, the stomach and duodenum were opacified with 300 ml oral barium. In all patients conventional SE T1- and T2-weighted images and fat-suppressed axial and oblique T1-weighted images of the upper abdomen and the pancreas, respectively, were obtained. The different T1-weighted sequences were compared for visualization of the pancreas and for lesion conspicuity. Oblique images were obtained in a plane parallel to the overall axis of the pancreas. All sequences were qualitatively assessed by two independent blinded readers and statistically compared. RESULTS: The combination of fat suppression and oblique imaging significantly improved the visualization of the different anatomic portions of the normal pancreas as well as pathologic findings in the pancreas in 70-92% of the cases compared with conventional axial T1-weighted imaging (p < 0.001) and in 52-75% of the cases compared with axial fat-suppressed T1-weighted imaging (p < 0.001), respectively. Increased image noise and blurring artifacts resulted in slight image degradation after Gd-DTPA administration. Barium as a duodenal contrast agent was beneficial for delineation of the pancreatic head from the adjacent bowel structures. CONCLUSION: In pancreatic imaging, fat-suppressed T1-weighted imaging is superior to conventional T1-weighted imaging, and oblique imaging is superior to axial imaging. Intravenous Gd-DTPA administration was useful only in selected cases.