MR cholangiopancreatography in patients with primary sclerosing cholangitis: interobserver variability and comparison with endoscopic retrograde cholangiopancreatography.

OBJECTIVE: The purpose of our study was to determine the degree of interobserver variability and correlation between MR cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP) for the presence of bile duct strictures in patients with primary sclerosing cholangitis. MATERIALS AND METHODS: For this retrospective study involving 26 patients with primary sclerosing cholangitis, 31 MR cholangiopancreatograms were compared with 30 endoscopic retrograde cholangiopancreatograms. The MR cholangiopancreatograms were independently interpreted by two abdominal radiologists in a blinded, randomized manner for overall image quality, extent of ductal visualization, and the presence and location of bile duct strictures. Unweighted multirater kappa coefficient values were estimated for each comparison. RESULTS: Visualization of more than 50% of the expected ductal length was possible in the extrahepatic, central intrahepatic, and peripheral intrahepatic bile ducts in 99%, 88%, and 69% of the MR cholangiopancreatograms and 100%, 86%, and 52% of the endoscopic retrograde cholangiopancreatograms, respectively. Strictures were detected in the extrahepatic, central, and peripheral ducts in 53%, 68%, and 87% of the MR cholangiopancreatograms and 73%, 67%, and 63% of the endoscopic retrograde cholangiopancreatograms, respectively. The interobserver agreement for stricture detection was 61% for MR cholangiopancreatography and 76% for ERCP. MR cholangiopancreatographic findings were consistent with ERCP findings for the presence of strictures in 69% of the cases. CONCLUSION: In patients with primary sclerosing cholangitis, MR cholangiopancreatography better shows the bile ducts and can depict more strictures, especially of the peripheral intrahepatic ducts, than ERCP. MR cholangiopancreatography can be used to noninvasively diagnose and follow up patients with primary sclerosing cholangitis.

Canine abdominal MRI at 8 Tesla: initial experience with conventional gradient-recalled echo and rapid acquisition with relaxation enhancement (RARE) techniques.

PURPOSE: In this manuscript, we present our initial experience with MRI of the abdomen at 8 T of canine subjects both alive and dead. Our hypothesis is that abdominal imaging at 8 T should be possible and should demonstrate unique information. To our knowledge, this is the first description of imaging characteristics of the abdomen at such field strengths using a human MR scanner. METHOD: An 8 T, 80 cm magnet housed in our department since 1998 was used for our study. GRE and rapid acquisition by relaxation enhancement (RARE) pulse sequences were selected to give reasonable slice profiles with relatively low power. Three dogs were imaged alive and after being killed. RESULTS: Our initial results show excellent signal-to-noise ratio and good RF penetration. Structures in the center of the abdomen were well visualized. Homogeneous signal was noted throughout each image without dielectric resonance artifact. Magnetic susceptibility artifacts were most severe on the GRE sequences. On the GRE sequences, the images appeared relatively T2 weighted. Signal voids were seen due to gas in the lung and bowel and susceptibility artifact at subcutaneous fat-muscle boundaries. The liver and spleen showed similar signal intensity, hypointense to subcutaneous muscle at low TE values. There was little internal anatomy of the liver or spleen visible except for the vessels. The kidney, in contrast, demonstrated very good internal structure with visualization of the cortex and medulla. Linear signal voids were depicted in the expected location of normal renal vascular anatomy on the GRE sequences. On the RARE sequences, the images also appeared T2 weighted. Magnetic susceptibility artifacts at subcutaneous fat-muscle boundaries were absent. Signal voids were noted in vessels with blood flow and gas. The liver and spleen were of similar signal intensity and slightly hypointense to muscle. The kidney and pancreas were of higher signal intensity than liver and subcutaneous muscle. The gallbladder wall demonstrated a striated pattern of two layers, with an inner hypointense and an outer hyperintense layer on the RARE sequence. The gastric wall demonstrated a striated pattern of five layers on the RARE sequence. CONCLUSION: Images of the dog abdomen with the world's first ultra high field 8 T magnet show robust image quality and excellent spatial resolution. Image contrast is greatest on the RARE sequence, and susceptibility artifact is strongest on the GRE sequence.

Detection of bile duct leaks using MR cholangiography with mangfodipir trisodium (Teslascan).

Mangafodipir trisodium (Teslascan), a hepatobiliary contrast agent, has the potential of providing functional biliary imaging similar to hepatobiliary scintigraphy. To our knowledge. the potential role of this biliary contrast agent in the detection of bile duct leaks has not been reported. In this case report, we report the first case of a bile duct leak diagnosed with enhanced MRI with mangafodipir trisodium in a patient following laparoscopic cholecystectomy. Our case illustrates that functional MR cholangiography images can be successfully acquired by using a post-mangafodipir fat-suppressed GRE technique and that bile duct leaks can be detected.

Cirrhosis: spectrum of findings on unenhanced and dynamic gadolinium-enhanced MR imaging.

The appearance of the cirrhotic liver on computed tomography can be difficult to evaluate and can frustrate the radiologist distinguishing benign from malignant lesions. Hepatic edema, fibrosis, atrophy, and vascular abnormalities are common in the cirrhotic liver and produce derangements in morphology, attenuation, and perfusion, limiting the accurate characterization of hepatic masses. With the development of fast magnetic resonance (MR) sequences and dynamic postgadolinium-enhanced imaging, most hepatic lesions with uncertain etiology on computed tomography can be accurately characterized on MR imaging. We describe MR imaging techniques useful for imaging cirrhosis and its complications. We also illustrate the spectrum of findings in the cirrhotic liver on dynamic gadolinium-enhanced MR imaging, including reticular and confluent fibrosis, fatty infiltration, hemochromatosis, regenerating nodules, dysplastic nodules, hepatocellular carcinoma, and sequela of portal hypertension.

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety).

The short-term safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 micromol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP.

Primary angiosarcoma of the spleen--CT, MR, and sonographic characteristics: report of two cases.

Primary angiosarcoma of the spleen is a rare entity, but it is the most common primary splenic malignancy. These tumors demonstrate an aggressive growth pattern and can be single or multiple. The diagnosis should be suspected in a patient who presents with splenomegaly but without evidence of lymphoma, malaria, leukemia, or portal hypertension. The tumor may also present with acute abdominal symptoms secondary to spontaneous splenic rupture. We describe two cases of primary angiosarcoma of the spleen with computed tomographic, magnetic resonance, and sonographic features.

Comparison of no medication, placebo, and hyoscyamine for reducing pain during a barium enema.

OBJECTIVE: We carried out a prospective, randomized study to evaluate the usefulness of premedication with an oral anticholinergic for relief of pain during and after a barium enema of the colon. SUBJECTS AND METHODS: Patients were randomized into three groups: no medication, placebo, and sublingual 1-hyoscyamine sulfate. The placebo or hyoscyamine tablet was placed under the tongue 15-30 min before the examination. After the procedure the patients were interviewed. An analog scale (0-10) was used to score the level of pain that the patients experienced during the examination. Forty-eight hours after the examination, the patients returned by mail a survey that used the same scale and asked about delayed pain. RESULTS: Data from 110 patients were studied. Sixty-nine patients were women, and 41 were men. They ranged from 24 to 82 years old (mean, 55 years). For the no-medication group (n = 36), the mean pain score was 4.1; for the placebo group (n = 34), 3.8; and for the hyoscyamine group (n = 40), 4.2. No statistically significant difference in pain scores was found between any groups (p = .72). Six patients from each group reported minor side effects. The mean scores from the returned surveys (n = 79) were 3.8 for the no-medication group (n = 26) and placebo group (n = 22) and 3.1 for the hyoscyamine group (n = 31). No statistically significant difference was found between any of these groups (p = .48) or between delayed pain responses and initial pain responses (p = .27). CONCLUSION: Although safe, hyoscyamine seems to provide no benefit over no drug or a placebo when used as a pain premedication for patients undergoing a barium enema.

Utilization review of simultaneously ordered multiple radiologic tests for the same symptom.

The purpose of this study was to analyze the utilization of multiple radiologic procedures ordered simultaneously for the same clinical problem. The method was a retrospective study of patients referred to an urban community hospital who had multiple radiologic tests ordered simultaneously before the referring physician reviewed any of the results. Utilization Findings Codes, beta versions II and III, of the American College of Radiology were applied. In- and outpatient charts were reviewed for initial indication, subsequent diagnosis, and treatment. Ninety-three patients had 214 radiologic examinations (2.3 per patient). Of the 214 total, 129 (60%) were retrospectively coded as inappropriate (beta II version). For 98 reports, the initial interpreting radiologist's coded 16% as inappropriate versus 55% when retrospectively coded by the authors (P < 0.0001). After applying the beta III version, 18% were coded as positive (and related to symptoms), 79% negative, and 3% equivocal. There were 161 (74%) examinations ordered by primary care physicians and 53 tests ordered by specialists. Using the beta III version, the negative rate for primary care physicians was 81 and 75% for specialists (P = 0.447). It was concluded that ordering multiple radiologic tests simultaneously on the same patient resulted in a high number of inappropriate procedures and negative results.

Radiographic manifestations of eosinophilic gastroenteritis.

Eosinophilic gastroenteritis (EG) is a rare inflammatory disease of unknown etiology, characterized by focal or diffuse eosinophilic infiltration of the gastrointestinal tract. Although little over 250 cases of EG have been reported in the literature, EG is probably more common than reports in the literature would indicate. A retrospective review of 25 patients with EG along with a review of the literature was done to identify clinical, laboratory, radiographic, and therapeutic features. An allergic disorder was present in 14 (56%) and a peripheral eosinophilia was present in 24 (96%) of our patients. The most common radiographic manifestations of the stomach and small bowel included stenosis and fold thickening, respectively. Thirteen patients had esophageal involvement, with the esophageal stricture being the most common abnormality found in these patients. Steroids produced a good therapeutic result in most patients; the remaining patients responded to cromolyn and/or surgery.

CT vs MRI in diagnosis of recurrent rectosigmoid carcinoma.

OBJECTIVE: Our goal was to compare the relative values of MRI vs. CT in diagnosing recurrent rectosigmoid cancer. MATERIALS AND METHODS: We conducted a retrospective review of 18 patients who had surgical resection of primary rectosigmoid carcinoma and suspected recurrence. They were studied with CT and MR and followed for up to 4 years. RESULTS: At the time of the initial imaging, 10 patients had recurrent tumor and 4 of the remaining 8 patients later demonstrated local recurrence. Magnetic resonance demonstrated 91% sensitivity, 100% specificity, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 89% with a 95% accuracy. Computed tomography demonstrated a sensitivity of 82% and a specificity of 50% with a PPV of 69% and an NPV of 67% with an accuracy of 68%. In three cases interpreted on CT as presacral masses, all were shown on MR to represent displaced but normal pelvic structures. In four cases MR revealed tumor involving the sacrum and sacral nerves not apparent on CT. CONCLUSION: Magnetic resonance showed superior sensitivity, specificity, and accuracy to CT and better definition of the extent of tumor.

Antispasmodic drugs to reduce discomfort and colonic spasm during barium enemas: comparison of oral hyoscyamine, i.v. glucagon, and no drug.

OBJECTIVE: Parenterally administered glucagon is currently the agent of choice for reducing abdominal discomfort and colonic spasm during a barium enema. Because glucagon is expensive and frequently causes nausea, we evaluated the use of oral hyoscyamine sulfate as an alternate agent and compared it with IV glucagon and no medication. SUBJECTS AND METHODS: A total of 349 adult patients undergoing barium enema examinations were randomly assigned in a prospective fashion to one of four groups: (1) no medication (87 patients); (2) 1 mg of IV glucagon (88 patients); (3) 0.125 mg of oral hyoscyamine sulfate (87 patients); and (4) 0.25 mg of oral hyoscyamine sulfate (87 patients). The degree of distension of the colon on radiographs obtained after fluoroscopy, the amount of abdominal distress after the procedure, and the number of side effects (nausea, palpitations, blurred vision, dry mouth) were analyzed. To evaluate the amount of abdominal discomfort more completely, we asked the last 248 patients to estimate the level of severity of the discomfort (none, mild, moderate, or severe). RESULTS: We found no difference in the degree of distension of the colon in the four groups (p = .63). Most patients (79%) had some degree of abdominal discomfort. Fewer patients in the group who received no medication (10%) had no or mild pain compared with those given glucagon (15%, p < .05), 0.125 mg of hyoscyamine (14%, p < .05), or 0.25 mg of hyoscyamine (12%, p = .15). Less nausea occurred in the group that received 0.125 mg of hyoscyamine than in the other groups (p < .03). No patients in any of the groups had allergic or severe side effects. CONCLUSION: When compared with IV glucagon, oral hyoscyamine had fewer side effects, but the degree of colonic distension or abdominal distress was not significantly different. In addition, hyoscyamine is considerably less expensive than glucagon and can be given orally. Patients who received medications had less discomfort than those who did not. However, the degree of distension was not different.

Positive bowel contrast agent for MR imaging of the abdomen: phase II and III clinical trials.

PURPOSE: To evaluate the efficacy and safety of two dose levels of an orally administered ferric ammonium citrate-based contrast agent for bowel enhancement on T1-weighted spin-echo magnetic resonance (MR) images in 222 patients with known or suspected abnormality of the upper abdomen. MATERIALS AND METHODS: Adverse reactions were graded for intensity, frequency, duration, and relationship to the contrast agent. Twelve unblinded readers compared enhanced with unenhanced images; all MR images were evaluated by two independent offsite radiologists in a blinded review. RESULTS: No statistically significant changes in mean vital signs or laboratory values were seen. Forty-eight of 220 patients (22%) reported minor side effects. The readers found increased intraluminal signal intensity and improved contrast enhancement of the gastrointestinal tract and distention and improved signal homogeneity in 101-107 cases (89%-98%) after ingestion; the blinded reviewers' findings were similar. CONCLUSION: The contrast agent provided new or additional radiologic information in 142 patients (64%), specific additional information in a detected abnormality in 46 of 142 patients (32%), and information that changed diagnosis, management, or surgical approach in 22 of 142 patients (15%).

Magnetic resonance angiography in the preoperative evaluation of abdominal aortic aneurysms.

Magnetic resonance angiography (MRA) and magnetic resonance imaging (MRI) are noninvasive techniques of visualizing blood vessels without the use of intravenous contrast or ionizing radiation. This prospective study assessed preoperative MRA and MRI in the evaluation of 28 patients with abdominal aortic aneurysm (AAA). MRI and MRA accurately predicted the extent of cephalad AAA, the patency of the superior mesenteric artery, and the course of the left renal vein, but were less accurate in defining the extent of caudal AAA, flow of the inferior mesenteric artery, and multiple renal arteries. This study suggests that MRI and MRA are alternatives to the combination of angiography and computed tomographic scan in the preoperative evaluation of patients with suspected AAA and no evidence of mesenteric or renal ischemia. When combined with preoperative segmental Doppler arterial studies, an accurate surgical plan may be formulated. Further refinements in image acquisition and postprocessing software analysis will advance the use of MRI and MRA for complete evaluation prior to elective AAA repair.