Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI

Background: To evaluate the changes of liver parenchymal enhancement in the cirrhotic liver by means of triple-phase dynamic magnetic resonance (MR) imaging. Methods: Triple-phase multisection dynamic MR imaging was performed in 32 patients with liver cirrhosis. The control group consisted of 19 patients without liver cirrhosis. After precontrast images were obtained, arterial phase images were acquired 20 s after the start of intravenous bolus administration of 0.10 mmol/kg of gadopentetate dimeglumine. Portal and delayed phase images were then acquired 1 and 3 min, respectively, after the injection of contrast material. On each phase image, the signal-to-noise ratio (S/N) from the liver parenchyma was measured by operator-defined regions of interest (ROIs). The contrast-enhanced ratio (CER) on each phase was then obtained according to the following formula: [S/N(arterial or portal or delayed phase image) − S/N(precontrast image)]÷ S/N(precontrast image). The portal perfusion index (PPI) also was obtained according to the following formula: [S/N(portal phase image − S/N(arterial phase image)]÷ S/N(arterial phase image). The results were expressed as mean ± SD. Results: The CERs of arterial, portal, and delayed phase images in patients with and without liver cirrhosis were 0.256 ± 0.211, 0.640 ± 0.384, and 0.554 ± 0.318 and 0.132 ± 0.094, 0.404 ± 0.204, and 0.324 ± 0.144, respectively. The CERs were highest in the portal phase and lowest in the arterial phase in patients with and without liver cirrhosis. The CER of the cirrhotic liver was significantly higher than that of the normal liver in every phase (p < 0.05). PPIs with and without liver cirrhosis were 2.90 ± 4.03 and 3.86 ± 3.89, respectively. The PPI with liver cirrhosis was significantly lower than that without liver cirrhosis (p < 0.05). Conclusion: The enhancement of cirrhotic liver parenchyma is greater than that of the normal liver parenchyma at every phase of triple-phase dynamic MR imaging. Received: 17 August 2000/Revision accepted: 7 March 2001     

Detection of pancreatic adenocarcinoma: relative value of arterial and late phases of spiral CT

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. Received: 1 August 1995/Accepted: 12 September 1995     

Heterotopic pancreas of the stomach: CT findings correlated with pathologic findings in six patients

Background: The purpose of this study was to characterize the computed tomographic (CT) findings of heterotopic pancreas of the stomach. Methods: CT scans of six surgically proven cases of heterotopic pancreas of the stomach were reviewed. Three were dynamic spiral CT scans, with both arterial dominant and late phase scans. In other three, both unenhanced and contrast-enhanced scans were obtained by using conventional techniques. Particular attention was given to the enhancement of the heterotopic pancreas. Pathologic and surgical findings were correlated with CT findings. Results: The locations were in the gastric antrum in five cases and in the mid-body in one. Size ranged from 1 cm to 3 cm (mean = 2.1 cm). Three cases showed homogeneous, strong enhancement similar to the pancreas and consisted mainly of pancreatic acini with the same histologic features as the normal pancreas. Two cases showed poor enhancement and consisted mainly of ducts and hypertrophied muscle; pancreatic acini were a minor component. In one case appearing as a cystic lesion on CT, a pseudocyst was found with many ducts and some nests of pancreatic acini. Conclusions: Heterotopic pancreas of the stomach showed a diverse spectrum of CT findings. Good understanding of these CT findings may be helpful in making a correct diagnosis. Received: 24 March 1999/Accepted: 19 May 1999     

Significance of hyperattenuating and contrast-enhancing hepatic nodules detected in the cirrhotic liver during arterial phase helical CT in pre–liver transplant patients: radiologic–histopathologic correlation of explanted livers

Background: Hyperattenuating nodules detected by arterial phase helical computed tomography (HCT) in patients with cirrhosis usually are believed to represent hepatocellular carcinomas (HCCs). We correlated HCT morphology of hyperattenuating hepatic nodules detected during arterial phase scans with the histopathology of explanted livers of patients with hepatic cirrhosis undergoing liver transplantation. Methods: Three hundred fifty-four patients had arterial and portal phase HCT performed before subsequent hepatic transplantation. Each patient received 180 mL of contrast by power injection at 5 mL/s. All hyperattenuating nodules detected on arterial phase HCT were assessed for morphology and evidence for contrast enhancement. Explanted livers in all patients were then sectioned at 10-mm intervals, and the histology of the nodules was correlated with the HCT findings. Results: Sixty-one hyperattenuating nodules were detected on the arterial phase HCT in 43 patients: 41 nodules were benign regenerating nodules (RN), three were dysplastic nodules (DP), and 17 were HCCs. Most RN/DP nodules were 5–20 mm in diameter, had distinct margins, were homogeneous, and were isoattenuating on precontrast, portal, and delayed scans. Thirty-six showed positive contrast enhancement and displayed a wide range of attenuation profiles. HCC nodules were 6–50 mm. All showed positive contrast enhancement and displayed a wide range of attenuation profiles. Conclusion: Hyperattenuating nodules seen on arterial phase HCT are likely to be RN/DP nodules. In many cases, it is not possible to distinguish between RN/DP and HCC. Thus, clinical decisions regarding inclusion criteria for transplantation based on CT morphology of liver lesions may be tenuous.     

Retroperitoneal cyst: sonographic findings

Background: Retroperitoneal cyst (RC) is a relatively rare disease, and its sonographic (US) findings have not been analyzed sufficiently. Methods: We studied US findings of five patients with RC, with special attention to location, size, shape, internal echoes, the presence or absence of lateral shadowing, and the mode of back echoes. Results: In all cases, the cyst was situated behind (four cases) or lateral to (one case) the pancreas: behind or lateral to the pancreatic head in two cases, behind the pancreatic body in one case, and behind the pancreatic tail in two cases. Four cases showed a round mass (three cases) or multiple round mass (one case). Internal echoes were present in those cases and showed a “pseudo-solid” pattern. In those cases, M-mode US confirmed the movement of those internal echoes. In the remaining case, the lesion was imaged as an irregularly shaped multilocular mass. No case showed posterior echo enhancement, and no case showed lateral shadowing. No blood flow signals from the lesion were seen. Conclusion: Unlike ordinary cysts, RC usually is imaged as a round mass behind the pancreas, with dense internal echoes without lateral shadowing or posterior echo enhancement, which presents a “pseudo-solid” pattern. A diagnosis of RC should be considered when encountering a mass with such US findings. Received: 6 June 2001/Accepted: 25 July 2001     

Logistic advantages of four-section helical CT in the abdomen and pelvis

Background: Multisection helical computed tomography (CT) has the potential for providing data sets with better section profiles, more anatomic coverage, and shorter breath-holding periods. Our purpose was to quantitate these advantages in a clinical setting when imaging the abdomen and pelvis. Methods: CT parameters including collimation, timing, z-axis coverage, and milliamperes were gathered retrospectively for the image set of both single-section (GE CT/i with 0.8-s rotation) and four-section (GE QX/i Lightspeed with 0.8-s rotation) helical CT scanners. Data were recorded for the abdomen and pelvis CT (n= 30 each), dual-phase liver CT including the pelvis (n= 15 each), and dual-phase pancreas CT (n= 15 each). Results: The abdominal and pelvic CT averaged 128.4 ± 5.4 s for single-section scanners (70-s delay, two breath-holds of 21.1 and 17.7 s with a 19.5-s interscan delay) and 92.2 ± 2.2 s for the four-section scanner (70-s delay and a 22.2-s breath-hold; p < 0.0001). For the dual liver and pelvis CT, single-section scanners averaged 119.9 ± 7.5 s (30-s delay, 15.8-s arterial phase, 20.0-s interscan delay, 21.2-s venous phase, 19.5-s interscan delay, and 14.2 s for the remaining abdomen and pelvis), whereas the four-section scanner averaged 86.8 ± 2.5 s (30-s delay, 6.7-s arterial phase, 27.9-s interscan delay, and 21.8-s venous phase including the pelvis; p < 0.0001). For the dual pancreas CT, single-section scanners averaged 86.7 ± 2.5 s (20-s delay, 28.3-s arterial phase, 17.8-s interscan delay, 21.7-s venous phase), whereas the four-section scanner averaged 78.0 ± 2.9 s (20-s delay, 9.7-s arterial phase, 30.7-s interscan delay, 13.0-s venous phase; p < 0.0001). Conclusion: CT scanners having four-section technology can reduce overall data acquisition times by 10–30% and total milliamperes by 50–60% depending on the protocol with thinner slice profiles. RID=" ID=" <E5>Correspondence to:</E5> R. C. Nelson Received: 8 December 1999/Revision accepted: 22 March 2000     

A percutaneous biopsy technique for patients with suspected biliary or pancreatic cancer without a radiographic mass

Background: Treatment of malignant pancreatic and/or biliary strictures requires tissue diagnosis. Since cytologic brushings at endoscopic retrograde cholangiopancreatography (ERCP) of these strictures has a poor sensitivity for malignancy (30–83%) (see ME Ryan. Gastrointestinal Endoscopy 1991;37(2):139–143; and MB Cohen, Wittchow RJ, Johlin FC, et al. Mod Pathol 1995;8:498–502), tissue diagnosis must be obtained by another route. We report our experience of percutaneous biopsy of malignant pancreatic and/or biliary strictures even when no radiographic mass is present. Methods: At ERCP, five patients demonstrated pancreatic and/or biliary duct strictures, had atypical cytological brushings, and had their strictures stented. No mass to account for the strictures could be identified on CT. These five patients underwent percutaneous biopsy of the peri-stent material by CT within 10 days of the ERCP. Results: Two patients had adenocarcinoma of the pancreas. One patient had malignant lymphoma and another had cholangiocarcinoma. One patient had inflammatory cells and was followed. Conclusions: If the diagnosis of malignancy cannot be made at the time of the ERCP sampling, then our experience suggests that a percutaneous biopsy should be performed even if a mass is not present using the stent as a target. Received: 30 January 1996/Accepted: 28 March 1996     

Hyperattenuating insulinoma at unenhanced CT

We report a case with insulinoma that showed higher attenuation than normal pancreatic parenchyma on precontrast CT. Pathology of the surgical specimen revealed the presence of psammoma bodies, which were responsible for hyperattenuation. It is worthwhile to obtain precontrast CT in patients suspected of having insulinoma. Received: 22 December 1994/Accepted: 4 February 1995     

Diffusion-weighted MR imaging with single-shot echo-planar imaging in the upper abdomen: preliminary clinical experience in 61 patients

Background: To determine the potential ability of diffusion-weighted magnetic resonance (MR) imaging with single-shot echo-planar imaging (DW imaging) in the upper abdomen by apparent diffusion coefficient (ADC) and signal:intensity ratio (SIR) measurements. Methods: DW imaging was performed in 61 clinical patients. ADCs in the liver, pancreas, spleen, kidney, and different pathological conditions were calculated. Spleen-to-liver SIR and segmental intensity difference of the liver (SID) were also calculated. Results: The mean ADCs (mm²/s) were 2.28 × 10⁻³± 0.07 in the liver, 1.44 × 10⁻³± 0.05 in the spleen, 1.94 × 10⁻³± 0.19 in the pancreas, and 5.76 × 10⁻³± 0.06 in the kidney. The mean ADC of cirrhotic liver was 1.96 × 10⁻³± 0.62, which was lower than that of normal liver. Other pathologic conditions also showed ADCs different from those of normal tissues. All DW images showed significantly higher spleen-to-liver SIRs and SIDs than did T2-weighted images (p < 0.05). Conclusion: The mean ADCs obtained with DW imaging were different in each upper abdominal organ and with each pathologic condition. DW images showed better soft tissue contrast than did T2-weighted images with regard to SIR and CNR in depicting and characterizing upper abdominal disorders. Received: 24 July 1998/Revision accepted: 2 December 1998     

Abdominal tuberculous lymphadenopathy: MR imaging findings

Background: The purpose of this study was to evaluate the utility of magnetic resonance imaging (MRI) as a diagnostic tool in abdominal tuberculous lymphadenopathy. Methods: MRI studies of 11 patients with histologically proven abdominal tuberculous lymphadenopathy were reviewed with regard to anatomic distribution, size, shape, degree, and pattern of enhancement and relation of the lesions to adjacent structures. Results: The most common site of involvement was the periportal area (n= 6), followed by the peripancreatic (n= 5), mesenteric (n= 1), and paraaortic (n= 1) areas. Eight patients were readily diagnosed as having tuberculous lymphadenopathy on abdominal computed tomography. Three patients had a heterogeneously enhancing masslike lesion adjacent to the pancreas and were initially diagnosed as having cystic tumor of the pancreas. On MRI, 11 lesions showed T1 iso- or hypointensity and central T2 hyperintensity. Two lesions showed T1 iso- or hypointensity and central T2 hypointensity. The lesions with different T2 signal intensities showed different patterns of enhancement on contrast-enhanced dynamic studies. The relations between the enlarged lymph nodes and adjacent bile ducts or vascular structrues were well depicted on MRI. Conclusion: MRI was useful in differentiating enlarged lymph nodes abutting the pancreas initially diagnosed as cystic neoplasms on abdominal computed tomography. RID=" ID=" <E5>Correspondence to:</E5> M.-J. Kim Received: 9 May 2000/Accepted: 14 June 2000     

Altered flow dynamics of intravascular contrast material to the liver in superior vena cava syndrome: CT findings

Background: To evaluate the findings of altered flow dynamics in the livers of patients with obstruction of superior vena cava (SVC) on helical computed tomography (CT). Methods: In six patients (age range = 28–80 years) with SVC obstruction, CT findings were retrospectively reviewed to identify the abnormal enhancement patterns of the liver and the relation with the extrahepatic collateral vessels and hepatic vessels. Results: Abnormal hepatic enhancement was observed in the following four (A–D) portions: (A) anterior portion of segment IV (n = 5), (B) subdiaphragmatic portion of the liver (n = 4), (C) posterior portion of the right lobe (bare area; n = 1), and (D) lateral segment of the left lobe (n = 2). Two major collateral pathways to the liver were demonstrated as follows: A and D → from the umbilical vein to the left portal vein, and B and C → from the subcapsular vein to the bare area of the liver or to the hepatic veins. On helical CT, these collateral pathways were also clearly visualized. Conclusion: When these abnormal enhancements of the liver on CT are recognized within the liver, these findings indicate diversion of contrast material into collateral pathways to the liver with SVC obstruction. Received: 31 March 1999/Revision accepted: 25 June 1999     

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

Background: T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy. Methods: MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations. Results: Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2–9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas. Conclusion: The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy. RID="ID="<e5>Correspondence to:</e5> T. Fujita Received: 24 June 1997/Accepted after revision: 22 October 1997     

MRI of recurrent rectosigmoid carcinoma

Background: A prospective study was performed to determine the most reliable MRI criteria to distinguish recurrent rectosigmoid carcinoma from benign postoperative fibrosis. Methods: Twenty-two consecutive patients who were suspected to have recurrent rectosigmoid carcinoma were examined by T2 and precontrast and contrast enhanced T1 weighted images. The prospective interpretations, the presence of high signal on T2 weighted images, the shape of the margins of a mass and the degree of contrast enhancement were correlated with histology and follow up to determine their respective accuracies, sensitivities and specificities. Results: The best criteria for recurrent tumor was the combination of high signal on T2 weighted images, round margins and > 40% contrast enhancement, which had an accuracy of 92%, sensitivity of 100% and specificity of 85%. In patients who were more than one year postoperative the specificity was 100%. Conclusions: The most reliable MRI criteria for distinguishing recurrent rectosigmoid carcinoma from benign postoperative fibrosis are the combination of the signal intensity on T2 weighed images, the shape of the margins of a mass and the presence of greater than 40% contrast enhancement. Received: 6 February 1996/Accepted after revision: 19 June 1996     

Value of the dynamic and delayed MR sequence with Gd-DTPA in the T-staging of stomach cancer: correlation with the histopathology

Background: To evaluate the usefulness of dynamic and delayed magnetic resonance (MR) imaging in the T-staging of stomach cancer and to compare the enhancement pattern of the cancerous lesion and the normal wall. Methods: We performed MR imaging in 46 patients with stomach cancer (including four early gastric cancers and 42 advanced gastric cancers). Axial, sagittal, or coronal two-dimensional fast low-angle shot) MR images for the water-distended stomach were obtained with dynamic protocol, including precontrast images and images obtained 30, 60, 90, and 240–300 s after intravenous injection of the 0.1 mM Gd-DTPA/kg solution. We evaluated the thickness, interruption (or not) of the low signal intensity bands, and enhancement pattern of the cancerous wall and normal gastric wall. We prospectively evaluated the depth of cancer invasion, perigastric infiltration (extraserosal invasion), perigastric organ invasion, and regional lymph nodes and determined tumor staging on MR images. These MR evaluations including MR-determined staging were correlated with the surgicopathologic findings. Results: Stomach cancer was shown as having a thickened wall with a rapid enhancing pattern after intravenous Gd-DTPA administration. The mucosa (and/or submucosa) affected by stomach cancer showed an early enhancement pattern (30–90 s after Gd-DTPA administration) in 43 of 46 patients (93%). The normal gastric mucosa demonstrated a delayed peak enhancement pattern (>90 s after Gd-DTPA administration) in 29 of 46 patients (63%) and variable enhancement pattern in 17 of 46 patients (37%). An interrupted low signal intensity band or highly enhanced tumorous lesion penetrating through the gastric wall was seen in 17 of 19 pT3 patients (90%). Consistency between MR-determined staging and surgicopathologic staging occurred in three of four pT1 tumors (75%), 10 of 13 pT2 tumors (77%), 17 of 19 pT3 tumors (90%), and eight of 10 pT4 tumors (80%); overall accuracy was 83%. Overall accuracy of regional lymph node involvement, as determined by enhanced MR, was 52%; 24 of 46 node groups were positive. Conclusions: Dynamic and delayed MR imaging can be useful for predicting depth of cancer invasion, perigastric infiltration (extraserosal invasion), and perigastric organ invasion by gastric cancer. Received: 28 July 1998/Revision accepted: 27 January 1999     

Vascular involvement in pancreatic adenocarcinoma:reassessment by thin-section CT

We defined computed tomographic (CT) criteria of vascular involvement by pancreatic carcinoma and used these criteria to assess vascular involvement in 56 patients with pancreatic adenocarcinoma. CT of the pancreas was performed at 1.5-mm section thickness and 5-mm section intervals during a bolus phase of intravenous contrast enhancement. The type of vascular involvement was correlated with surgical and pathologic findings. When there was fat-plane (type A) or normal pancreatic parenchyma (type B) separating the tumor from adjacent vessels, the tumor could be resected without venous resection in 21 of 22 patients (95%). When the tumor was inseparable from the vessels but the points of contact formed a convexity against the vessel (type C), CT was not reliable in predicting whether or not the tumor was fixed against the vessel. When the tumor was partially encircling (type D) the vessel, the tumor was fixed against the vessels in most cases. The resectable rate was 47%, but resection would also require venous resection. When the tumor was completely encircling (type E) or occluding (type F<+>) the vessel, all tumors were not resectable with a negative margin. Thin-section CT with bolus intravenous contrast enhancement improved the ability to assess vascular involvement in pancreatic adenocarcinoma. Received: 14 April 1995/Accepted: 12 June 1995     

Dynamic enhancement of upper abdominal organs in normal volunteers with MRI and effects of contrast dose reduction

Background: To quantify enhancement parameters of the upper abdominal organs over time during magnetic resonance (MR) examinations and to evaluate the effect of a dose reduction of contrast medium on these parameters. Methods: Ten volunteers underwent two separate dynamic enhanced MR examinations with 0.1 and 0.075 mmol/kg of contrast medium, respectively. Breath-hold gradient-echo T1-weighted images were acquired every second for 118 s followed by delayed images. The percentages of enhancement, the time to maximum enhancement, and the area under the time-versus-enhancement curve were calculated for each organ. Results: The mean times to maximum percentage of enhancement were less than 25 s for the pancreas, kidneys, and spleen and 50 s for the liver. The mean values of maximum percentage of enhancement for the standard/reduced doses were 72%/62% (pancreas), 165%/155% (kidneys), 114%/87% (spleen), and 67%/53% (liver). This difference was significant when liver enhancement was considered (p= 0.02). In addition, when the areas under the time-versus-enhancement curves were compared, the difference between the standard dose and reduced dose was significant for all organs tested (p < 0.05). Conclusions: Dynamic scanning of the upper abdomen should start early after contrast injection. Injection parameters should be standardized to capture arterial and venous enhancements in liver examinations. A 25% dose reduction did not significantly affect peak enhancement (except for the liver) but did significantly reduce overall enhancement. Received: 8 September 1998/Revision accepted: 13 January 1999     

Helical CT anatomy of pancreatic arteries

Background: To assess the frequency of visualization of pancreatic arteries in the arterial phase of helical computed tomography (CT). Methods: The visibility of pancreatic and peripancreatic arteries in helical CT images was evaluated in 20 consecutive patients who had no evidence of pancreatic disease. CT examinations were performed by using a continuously rotating CT scanner and intravenous injection of contrast media. The scans were taken 35 s after the start of injection and with a table speed of 3 mm/s. Images were reconstructed in 3-mm section increments. Results: Frequently visualized arteries were the gastroduodenal, anterior and posterior superior pancreaticoduodenal, and right gastroepiploic arteries. Infrequently visualized arteries were the dorsal pancreatic, pancreatica magna, caudal pancreatic, transverse pancreatic, and common, anterior, and posterior inferior pancreaticoduodenal arteries. Conclusion: Helical CT enabled us to recognize small pancreatic arteries, and the evaluation of these arteries should be considered in the staging of pancreatic carcinoma. Received: 6 June 1995/Accepted: 22 July 1995     

MR imaging enhancement with superparamagnetic iron oxidein chronic liver disease: influence of liver dysfunction andparenchymal pathology

Purpose: To analyze the influence of liver dysfunction and parenchymal pathology on the accumulation of superparamagnetic iron oxide (SPIO). Methods: We evaluated MR images of 13 patients having small hepatic neoplasms before and after administration of SPIO (10 μmol/kg). Biopsy and laboratory data confirmed the presence of severe cirrhosis in two patients, mild cirrhosis in four, chronic hepatitis in five, and normal livers in two. Degrees of liver dysfunction or liver parenchymal pathology were correlated with reductions in signal intensity of the liver and spleen after administration of SPIO. Signal intensity reduction was evaluated using a 1.5 Tesla MR unit. Results: Response to SPIO of the liver and spleen did not correlate with liver parenchymal pathology, although reductions in signal intensity of the liver were somewhat small in severely cirrhotic livers. There were slight correlations between signal intensity alterations of the liver and laboratory data such as the indocyanine green retention rate (correlation coefficient 0.47), albumin (0.36), total bilirubin (0.36), and serum glutamic oxaloacetic transaminase (GOT) (0.46). Signal intensity reduction of spleen did not correlate with liver function tests except for serum GOT. In patients with cirrhosis, heterogeneous structures were detected in the nontumorous portions of the liver. However, these did not prevent the diagnosis of small hepatomas. Conclusion: The uptake of SPIO showed some correlation with liver function but not with chronic liver parenchymal pathology. SPIO provided sufficient contrast between tumor and surrounding liver parenchyma among patients with chronic liver disease. Received: 22 August 1994/Accepted after revision: 27 January 1995     

Four-year study of abdominal ultrasound in 900 Central African adults with AIDS referred for diagnostic imaging

Background: In the majority of sub-Saharan African countries, the absence of computed tomography facilities makes abdominal ultrasound (US) an alternative diagnostic tool in the clinical investigation of infectious and noninfectious complications of human immunodeficiency virus (HIV)–infected individuals. We studied the abdominal US findings in Central African adult AIDS patients to determine whether the findings were consistent between different population groups and neighboring countries. We performed a longitudinal study of AIDS patients and age- and sex-matched HIV-negative adults referred for abdominal US at two tertiary referral city hospitals: the Gecamines Sendwe Hospital (GSH), Lubumbashi, Congo, and the University Teaching Hospital (UTH), Lusaka, Zambia. Methods: Between 1992 and 1996, abdominal US findings in 900 adults (300 Congolese adults from GSH and 600 Zambian adults from UTH; age range = 15–55 years) with a diagnosis of AIDS referred for diagnostic imaging from the inpatient medical wards were recorded; 900 abdominal ultrasound findings from age and sex-matched HIV-negative adults were studied for comparative purposes. Results: Abdominal US for diagnostic purposes in AIDS patients is requested by clinicians for a range of primary clinical indications: abdominal pain, fever of unknown origin, hepatosplenomegaly, lymphadenopathy, and abnormal liver function tests. Compared with the HIV− individuals, the AIDS group of patients had a significantly higher proportion of splenomegaly (35% vs. 24%; p≤ 0.001), hepatomegaly (35% vs. 22%; p= 0.001), lymphadenopathy (31% vs. 11%; p≤ 0.001), biliary tract abnormalities (25% vs. 12%; p≤ 0.001), gut wall thickening (15% vs. 5%; p≤ 0.001), and ascites (22% vs. 9%; p≤ 0.001). There were no differences in renal tract and pancreatic abnormalities between the AIDS and HIV− groups. There were significantly fewer gallstones in the AIDS group (23% vs. 75%; p≤ 0.001). These patterns of abdominal US abnormalities were consistent across both hospitals. Conclusions: Diagnostic imaging by abdominal US is commonly used in the management of a variety of clinical indications in Central Africa. The changes seen on abdominal US in AIDS patients appear uniform across the two countries in Central Africa. These findings may have implications for the radiologist, especially in developing countries, where accurate microbiological or pathologic diagnosis of infectious and noninfectious diseases afflicting the HIV-infected patient is often not possible and US is sometimes relied upon as a “diagnostic” investigation by many physicians. Further studies are required to define patterns of clinical findings, plain films, and pathologic and laboratory correlates with US to develop and refine diagnostic algorithms for clinical use in resource-poor countries. Received: 24 June 1999/Revision accepted: 8 September 1999     

First experiences in CT-guided percutaneous transhepatic biliary decompression by means of real-time CT fluoroscopy

Background: Computed tomographic fluoroscopy (CTF), also called real-time CT, is increasingly used in interventional radiology but has not yet been recommended to guide percutaneous transhepatic biliary decompression (PTBD). We report our early clinical experiences with CTF-guided PTBD. Methods: Sixteen consecutive patients underwent PTBD under CTF guidance because of obstructive jaundice caused by malignant tumor (11 cases of carcinoma of the bile duct, four cases of pancreatic cancer, and one case of metastasis). CTF-guided PTBD was performed on a helical CT scanner and a surgical C arm. Main target parameters were the success and complication rates, the number of necessary punctures, the time needed for successful puncture of a suitable bile duct, and the patients' radiation exposure. Results: CTF-guided punctures of the bile duct for PTBD were successful on the first trial in 10 cases; in six patients, two hits were necessary. The time needed to hit a suitable bile duct was 6–21 s (median = 13 s). Therefore, the radiation exposure (skin) was 27–94.5 mSv. The additional implantation and stenting of the bile duct by means of the surgical C arm was uneventful in 15 cases. In one case, only external drainage could be achieved. Complications did not occur. Conclusion: CTF enables good visualization of the most suitable duct for puncture. Therefore, subsequent recanalization seems to be easier than other methods. Received: 19 June 2000/Accepted: 26 July 2000