Abstract: Portal vein aneurysm is very rare, and its relation to portal hypertension has been emphasized. We report six cases of portal vein aneurysm (five extrahepatic and one intrahepatic). All patients were asymptomatic and had no signs suggestive of portal hypertension; the lesion was incidentally detected by ultrasound. Color Doppler sonography showed a constant hepatopetal flow along the aneurysmal wall, which immediately led to the diagnosis. We stress the usefulness of color Doppler sonography for studying the hemodynamics of this vascular anomaly and briefly review the literature.

Abstract: Background: To assess the value of high resolution sonography (HRS) in identifying normal and inflammatory bowel wall in nondiverticular ileitis and colitis by using a segment-by-segment analysis.

Abstract: Background: This multi-institutional study examines appearances of pelvic fistulas on magnetic resonance (MR) images.

Abstract: Background: The purpose of this study was to describe the imaging findings of papillary adenoma of the bile ducts.

Abstract: Background: Positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) is a useful technique for detection of malignancy. The purpose of this study was to determine if FDG-PET scanning using visual and quantitative analyses can identify patients with recurrent colorectal tumor following abdominoperineal resection.

Abstract: Background: A prospective study was performed to determine the most reliable MRI criteria to distinguish recurrent rectosigmoid carcinoma from benign postoperative fibrosis.

Abstract: Background: The purpose of this study was to determine whether tiny (<2 cm) areas of iodized-oil retention diagnosed as intrahepatic metastatic nodules of hepatocellular carcinoma (HCC) at computed tomography (CT) following intraarterial injection of Lipiodol (Lipiodol-CT) correlate with truly cancerous foci on the corresponding sectioned pathologic specimens. Methods: Thirty-two consecutive patients with biopsy-proven HCC (26 men and six women, aged 41–72 years) underwent prospective evaluation with Lipiodol-CT before undergoing surgery (hepatic resection, 30 patients; liver transplantation, two patients). Imaging findings were correlated with intraoperative and pathologic findings. Results: Twenty-one areas of retained Lipiodol (0.5–1.6 cm in diameter, mean ± SD: 0.9 ± 0.3 cm) had features consistent with intrahepatic metastatic nodules of HCC on Lipiodol-CT scans. Nineteen of the 21 areas correlated with tumor deposits at pathologic examination of the surgical specimens, whereas two of 21 were due to abnormal retention of iodized oil within noncancerous liver parenchyma. The positive predictive value of findings at Lipiodol-CT for the diagnosis of intrahepatic metastatic nodule of HCC was 90.5%. Conclusions: Findings at Lipiodol-CT enable a reliable diagnosis of intrahepatic metastatic nodules of HCC.

Abstract: We present a patient with nodular regenerative hyperplasia of the liver (NRH) and portal vein absence studied with CT, MR imaging, and MR angiography. The most striking feature was exuberant hemorrhoids due to a giant hepatofugal inferior mesenteric vein. A relationship between unbalanced portal blood flow and nodular regenerative transformation of the liver is suggested in this patient.

Abstract: Background: Spiral computed tomography (CT) allows the pancreas to be imaged during peak contrast levels owing to the capability of fast data acquisition. The objective of this study was to evaluate the relative value of the arterial and late phases of spiral CT for detecting pancreatic adenocarcinomas. Methods: Twenty-two patients with pathologically proved pancreatic adenocarcinomas underwent two-phase spiral CT. The CT scans were performed with 5 mm collimation and 5 mm/s table speed. Images during the arterial and late phases were obtained at 30- and 180-second delays, respectively. The images of the arterial phase were compared with those of the late phase in terms of tumor conspicuity from surrounding pancreatic parenchyma and tumor detectability by means of a 3-point grading system: 1 (poor), 2 (fair), and 3 (good). Results: In terms of tumor conspicuity from surrounding pancreatic parenchyma, 16 lesions (73%) were good, 5 lesions (23%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 6 lesions (27%) were good, 9 lesions (41%) were fair, and 7 lesions (32%) were poor during the late phase (p= 0.0007). The arterial phase was superior to the late phase in 16 patients (73%) and equal in 6 patients (27%). For tumor detectability, 18 lesions (82%) were good, 3 lesions (14%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 10 lesions (45%) were good, 7 lesions (32%) were fair, and 5 lesions (23%) were poor during the late phase (p= 0.0033). For detectability, the arterial phase was superior to the late phase in 14 patients (64%) and equal in 8 patients (36%). Conclusion: The arterial phase of spiral CT is superior to the late phase, which is equivalent to conventional CT for detecting pancreatic adenocarcinoma.

Abstract: Background: Abdominal sonography, computed tomography (CT), angiography, and magnetic resonance (MR) imaging are the most widely used modalities for preoperative localization of insulinomas. CT and angiography are generally considered the techniques of reference, and the role of sonography and MR imaging in these patients is controversial. The purpose of this study was to compare these four modalities in a group of patients with pancreatic insulinoma and determine an effective radiological approach to this disease.

Abstract: Spontaneous hematoma in the iliopsoas muscle is a serious complication of anticoagulant therapy. It causes severe pain and often results in loss of function of the femoral nerve. We present two cases in which percutaneous decompression of the hematoma was successfully performed to relieve intractable pain and to support functional restoration of the femoral nerve.

Abstract: Background: Analysis of unenhanced and contrast-enhanced magnetic resonance (MR) images of struma ovarii, a rare benign neoplasm of the ovary, is the aim of this study. Methods: T2-weighted and Gd-DTPA-enhanced T1-weighted MR images of five histologically proven struma ovarii were evaluated retrospectively. Results: In all patients, unenhanced and contrast-enhanced T1-weighted MR images showed complex cystic masses composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles. In four patients, the cyst fluid was hypointense on T1-weighted images and hyperintense on T2-weighted images. In one patient, the fluid was hyperintense on T1-weighted images and hypointense on T2-weighted images due to hemorrhage. Conclusion: A complex mass composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles, appeared to be a characteristic MR finding of struma ovarii.

Abstract: Primary malignant lymphoma of the uterus is a rare disease. We present the MR findings in three cases where the uterus was the initial site. MR findings were retrospectively evaluated. Although the intact junctional zone is a specific finding for lymphoma, diffuse enlargement of the uterus and relatively homogeneous signal intensity on MR imaging in spite of large tumor size are helpful for diagnosing uterine lymphoma.

Abstract: We report the disappearance of liver cell adenoma, documented by computed tomography (CT) and magnetic resonance (MR) imaging. A 42-year-old woman with a diagnosis of hepatic adenoma was followed up by CT and MR imaging after cessation of oral contraceptive use. At the time of diagnosis, the adenoma was 4 cm in diameter and appeared hypervascular on CT. At MR imaging, the lesion was hypointense on T1-weighted sequences, and hyperintense on T2-weighted sequences. The lesion disappeared 4 years after cessation of oral contraceptive use. We conclude that in nonoperated patients CT scans and MR imaging are useful for following the evolution, and documenting the regression, of liver cell adenomas.

Abstract: Sonography is the screening method of choice for evaluating the adnexae, uterus, and fetus in the pregnant patient. However, there are circumstances in which an alternate imaging modality is needed for additional information. Pelvic magnetic resonance imaging (MRI) during pregnancy shows promise as a correlative imaging modality in pregnancy because it uses no ionizing radiation, provides excellent soft tissue contrast, and has multiple planes for reconstruction [1–7]. This modality has allowed for evaluation of adnexal masses [3, 8], pelvimetry [9–11], evaluation of placenta previa [6, 12, 13], and pelvic deep venous thrombosis [14] in the pregnant patient. In the past, the uses of obstetric MRI were predominately limited to extrafetal structures, given the degradation by artifacts arising from the motion of the fetus [2, 6, 15]. To improve image quality, investigators have sedated fetuses by giving the mother benzodiazepines [16, 17] and induced fetal paralysis by injecting pancuronium directly into the fetus through an amniocentesis needle [2]. As suggested by Stark et al. [10], studies in the third trimester with oligohydramnios are especially good for MR imaging because fetal motion in these cases is limited. Newer uses of MRI in the pregnant patient have taken advantage of fast scanning techniques to limit motion artifacts. These fast scans allow for the evaluation of fetal anatomy in the second trimester and in cases with normal fluid. This article will review the literature on use of MRI in obstetrics, with an emphasis on fetal anatomy with fast scan techniques.

Abstract: Focal lesions of the liver represent a significant diagnostic problem for various imaging modalities. The aim of this study was to assess the value of power Doppler sonography versus conventional color Doppler imaging in the depiction of hypervascular focal nodular hyperplasia (FNH) of the liver and to investigate the resistive index (RI) in the lesions' feeding arteries. Eighteen histologically proved FNHs in 14 patients were evaluated by gray-scale ultrasound, conventional color Doppler, and power Doppler sonography. With conventional color Doppler, a feeding arterial vessel could be depicted in only 4/18 lesions and hypervascularization was detected in 6/18 lesions. Power Doppler was more sensitive in detecting feeding arteries (16/18) within hypervascular lesions (15/18). RI values in the feeding arteries (mean = 0.51) significantly differed from those in the main hepatic artery or its intraparenchymal branches (mean = 0.68) in the same patient. The mean RI-difference was 0.19, suggesting hemodynamically significant arteriovenous shunting. Power Doppler sonography significantly increases sensitivity in the diagnosis of focal nodular hyperplasia of the liver and reliably permits the distinction of these lesions from hepatocellular carcinomas.

Abstract: We present a case of gastric liposarcoma, a very uncommon pathology; only nine cases have been reported in the literature. We describe the radiologic findings of this neoplasm and emphasize the correlation between computed tomography (CT) and the macroscopic morphology of the tumor, which is conditioned by its histology. In our case, CT demostration of fatty areas within the gastric mass facilitated the diagnosis. This finding has not been described for liposarcomas of the stomach.

Abstract: Spiral CT angiography may be a useful adjunct for interventional radiologists in imaging vessels within the abdomen and pelvis. Specifically, the potential to assess abdominal aortic aneurysms preoperatively is within the realm of spiral CT angiography so long as scanners can quickly change collimation and table feed during the examination. The technique is also useful for imaging metal and nonmetal vascular grafts. The splanchnic arteries may be imaged in instances in which proximal vascular patency and course is questioned. The portal vein and its branches may be imaged prospectively with spiral CT angiography or retrospectively by postprocessing routine abdominal CT image data. The normal renal vasculature including accessory vessels may be imaged as part of preoperative evaluation for renal transplantation or for repair of ureteropelvic junction obstruction. Renal artery aneurysms may also be followed with spiral CT angiograms. Hemodynamically significant renal arterial stenoses may be detected with spiral CT angiography; grading the severity of those stenoses is within the realm of spiral CTA so long as careful attention is paid to technique.

Abstract: A patient with active Crohn disease was evaluated by MRI at admission, clinical remission, and a new relapse. The MRI-estimated disease extension correlated with surgical findings, whereas ultrasonography underestimated and a small bowel series overestimated the extension. MRI disclosed the disappearance of intestinal edema at the time of clinical remission and, in contrast to ultrasonography, showed an abscess and a fistula, confirmed by surgery, at the new relapse.

Abstract: Background: To evaluate the appearance of the arrangement of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) on computed tomography (CT) in normal patients and in patients with abdominal masses. Methods: One hundred seventy-seven consecutive abdominal CT examinations of 143 adults and two children were reviewed. The relationship of the SMV to the SMA was recorded at four locations: the beginning of the mesenteric vessels and levels 3 cm, 6 cm, and 9 cm caudad to the beginning. The relationship of the SMV to the SMA was divided into four quadrants in relation to the SMA: I, ventral right or directly ventral; II, dorsal right or directly right; III, dorsal left or directly dorsal; and IV, ventral left or directly left. Results: In the beginning of the SMV–SMA complex and levels 3 cm, 6 cm, and 9 cm caudal to the beginning, the SMV was located in quadrant I in 146, 84, 69, and 43 examinations, in quadrant II in 31, 93, 71, and 27 examinations, in quadrant III in zero, zero, five, and three examinations, and in quadrant IV in zero, zero, nine, and 15 examinations, respectively. The cases with SMV inversion had neither malrotation nor adjacent tumor compression. All the cases with an adjacent tumor-induced compression of the SMV–SMA complex had a normal SMV–SMA relationship. Conclusion: In the first 3 cm, the SMV is always to the right of the SMA. Caudal to the level of 6 cm, the SMV may be located to the left of the SMA without evidence of malrotation. A midgut nonrotation is more likely to be present when a proximal SMV inversion is coexistent with a rightward direction of the proximal jejunal vessels. A hypothetical depiction of the step-by-step change of the SMV–SMA relationship during embryologic development may explain the arrangement patterns of the mesenteric vessels in normal rotation and midgut nonrotation.

Abstract: Background: To identify the reasons for misdiagnosis of the degree of stromal invasion by uterine cervical cancer with various magnetic resonance sequences. Methods: T2-weighted, dynamic, and postcontrast T1-weighted images were obtained in the sagittal plane in 20 patients with uterine cervical cancer. After evaluating these sequences for the degree of stromal invasion, histologic specimens were directly correlated with these images. Results: The degree of stromal invasion was correctly diagnosed in 15 of the 20 cases on T2-weighted images, in 12 on dynamic images, and in eight on postcontrast T1-weighted images. All misdiagnoses were due to overestimation. Histologically, peritumoral stroma showed inflammation or edema in two patients, whereas no histological abnormality was found in the other patients. A hyperintense rim, i.e., a peritumoral enhanced ring-shaped structure, was observed on the enhanced images of five patients. The hyperintense rim corresponded to the periphery of the tumor in three patients and to the cervical stroma in two patients. Conclusion: T2-weighted images permitted the most accurate evaluation of stromal invasion by uterine tumors. Overdiagnosis may be due to an abnormal intensity of the cervical stroma, which was observed more frequently on dynamic and postcontrast T1-weighted images than on T2-weighted images.

Abstract: Background: This study examines the minimally required imaging protocol needed for detection and staging of renal cell carcinoma (RCC). Methods: In 81 patients (21 women, 60 men; mean age = 62 years) with 85 RCCs, T1-weighted (T1WI), contrast-enhanced T1-weighted (Gd-T1WI), T2-weighted (T2WI), and gradient recalled echo–fast low flip angle shot (GRE/FLASH) images were evaluated alone and in combination. Surgical–pathological findings were available in all patients and were considered the standard of reference. Results: Tumor detection for lesions smaller than 3 cm was better on Gd-T1WI than on any other sequence, but only the comparison with noncontrast T1WI and GRE/FLASH was statistically significant (detection: T1WI = 33%, Gd-TIWI = 80%, T2WI = 60%, GRE = 47%). The respective accuracies of T1WI, Gd-T1WI, T2WI, and GRE/FLASH images were 81%, 78%, 71%, and 62% for evaluating local tumor extension; 90%, 88%, 89%, and 85% for lymphadenopathy; and 89%, 81%, 91%, and 95% for renal vein thrombus. The combination of T1WI and GRE sequences rendered the highest overall staging accuracy. Conclusion: For tumor detection, contrast-enhanced T1WI is necessary for lesions smaller than 3 cm. For tumor staging, although the addition of GRE results in significant improvement in the evaluation of venous thrombus, any combination of two sequences will result in similar accuracy, and the use of multiple sequences is not necessary.

Abstract: Gallbladder varices were correctly diagnosed by color Doppler sonography and computed tomography during arterial portography (CTAP) in two patients with portal vein thrombosis. One patient with multiple hepatocellular carcinomas showed extrahepatic and intrahepatic portal vein occlusion by a tumor thrombus. The other patient, with liver cirrhosis, had a portal vein thrombosis. Color Doppler sonography clearly showed the portal vein occlusion, cavernous transformation of collateral veins, and gallbladder varices that drained into the intrahepatic portal venous branches. The intrahepatic portal venous branch, connecting to the gallbladder varices, exhibited reverse flow from the periphery to the hilum of the liver. CTAP also demonstrated gallbladder varices communicating directly with the intrahepatic portal vein branches in both patients. Gallbladder varices developed as a venous collateral because of extrahepatic portal vein occlusion. Color Doppler sonography and CTAP are useful for detecting these varices and planning biliary surgery in patients with portal vein thrombosis.

Abstract: Computed tomographic angiography (CTA) is a minimally invasive technique for vascular imaging with the potential to become the primary imaging method for many angiographic applications in the abdomen. It is based on the rapid volume acquisition capabilities of spiral (or helical) CT and uses a properly timed intravenous contrast bolus to obtain a three-dimensional data set from the examined vascular region. This data set, consisting of overlapping transaxial CT images, can be interactively reviewed using arbitrary cut planes (multiplanar reformats), or it can be transformed into angiographic displays using maximum intensity projections (MIP) or three-dimensional shaded surface displays (SSD). Although there is an absolute limit to spatial resolution with CTA that precludes diagnostic assessment of abdominal vessels smaller than 1 mm, CTA has been shown to be an excellent tool for imaging the abdominal aorta and its large side branches [1–5]. Advantages over arterial angiography include use of the intravenous approach, direct information derived about vascular walls and perivascular structures, and the use of three-dimensional visualization techniques. With its fast acquisition time and relatively high spatial resolution, CTA compares favorably with MR angiography (MRA) and color-coded duplex ultrasonography. However, in contrast to these techniques, CTA images display only anatomic information and lack flow sensitivity. Although the basic idea of CTA is simple, there are numerous factors that influence image quality and may cause artifacts. Attention must be paid to scanning technique and contrast application in order to achieve diagnostic images of optimum quality. We describe our experience with more than 500 abdominal CT angiograms since 1991, discuss new developments in scan-

Abstract: Background: To assess the frequency and characteristics of nonpathological focal enhancements seen on spiral computed tomographic (CT) hepatic angiography (CTA).

Abstract: Infiltrating lobular carcinoma accounts for only a small fraction of breast carcinomas, with most patients having infiltrating ductal carcinoma. The metastatic patterns of ductal and lobular carcinoma have been shown to be markedly different. Infiltrating lobular carcinoma metastasizes significantly more often to the gastrointestinal tract, pelvic organs, peritoneum/retroperitoneum, and urinary tract than does infiltrating ductal carcinoma. This point has significance for follow-up, the diagnosis of abdominal symptoms, and the therapeutic options for these patients. This article illustrates the broad spectrum of abdominal metastases from lobular breast carcinoma that may be detected with computed tomographic and fluoroscopic examinations, and it describes the role of imaging in the diagnosis of metastatic disease in these patients.

Abstract: Percutaneous needle biopsy, performed under imaging guidance, has emerged as one of the most significant advances in radiology during the last two decades. It is now a widely accepted technique that can be used to establish the identity of masses in almost any location in the body. In this issue of Abdominal Imaging,Doctors Pelsang and Johlin, a radiologist and gastroenterologist working together, have presented a practical and elegant method for the percutaneous needle biopsy of pancreatic and bile duct strictures—two particular sites of pathologic processes from which it can be notoriously difficult to obtain diagnostic tissue samples [1]. The authors describe their results in five patients, who presented in their practice during a 4-month period with pancreatic and/or bile duct strictures. All of these patients had ‘‘atypical’’ cells obtained by cytologic brushings during ERCP, but the definitive diagnosis of malignancy could not be made by this method. In these cases, the radiologist was able to subsequently perform percutaneous needle biopsy, under CT guidance, using an endoscopically placed ductal stent as the biopsy target, even though no peri-stent mass was visible. In four of five cases (80%), a diagnosis of malignancy was made by this percutaneous biopsy method. The work by these authors demonstrates the complementary nature of endoscopic and percutaneous interventional techniques. Endoscopic retrograde cholangiopancreatography (ERCP) allows for the collection of cytologic material from suspicious ductal lesions by means of washings, brushings, and pinch biopsies. The reported sensitivity of the cytologic diagnosis of malignancy by these techniques ranges from 18 to 70%, with many reported accuracy rates lying at the lower end of this spectrum [2–4]. This low accuracy may be due to the fact that endoscopically obtained cytologic material

Abstract: Three patients with renocolic fistulas are presented. Antegrade or retrograde pyelography showed the fistula in one patient but was unsuccessful in two others. CT demonstrated perinephric inflammation extending to the colon, complex air-fluid collections within the kidney, or extension of renal contrast into the colon. CT and direct pyelography complement each other for the diagnosis of renocolic fistulas.

Abstract: Background: To elucidate the metallic factors contributing to the signal intensities of hepatocellular carcinoma (HCC) on T1-weighted magnetic resonance (MR) images and to determine whether or not changes in signal intensity contribute to the diagnosis of histological grading of HCC.