A new technique for the reconstruction of complex portal vein anomalies in right lobe living liver donors.

Living donor liver right lobe transplantation using donors with variation of the right sectorial portal vein is considered a challenging procedure in terms of the donor's safety and the complexity of reconstruction in the recipient. We describe an innovative technique to reconstruct double portal vein orifices via a deceased donor iliac vein graft. The postoperative course of the recipient was uneventful. Doppler ultrasound on the fourth postoperative month revealed equivalent flow in both portal vein branches. Reconstruction of double right portal vein branches using a cryopreserved iliac vein is a valuable technique for utilizing right lobe grafts with challenging portal vein anatomy.

MRI and S-MRCP findings in patients with suspected chronic pancreatitis: correlation with endoscopic pancreatic function testing (ePFT).

PURPOSE: To review magnetic resonance imaging (MRI) and secretin stimulated magnetic resonance cholangiopancreatography (S-MRCP) findings of patients with suspected chronic pancreatitis and compare them with endoscopic pancreatic function testing (ePFT). MATERIALS AND METHODS: MRI and S-MRCP findings of 36 patients with clinically suspected chronic pancreatitis were reviewed. Baseline ductal changes, duodenal filling grades, and pancreatic duct caliber change (PDC) on S-MRCP, mean values of pancreatic anteroposterior (AP) diameter, signal intensity ratio (SIR) between pancreas and the spleen on T1-weighted fat saturated images, and arterial to venous (A/V) enhancement ratios were compared between groups of normal and abnormal pancreatic exocrine function determined by ePFT. RESULTS: All patients (n = 24) with normal ePFT (HCO(3) >80 mEq/L) had grade 3 normal duodenal filling. Patients with abnormal ePFT (HCO(3) <80 mEq/L) (n = 12) had grade 1 (n = 1) and grade 2 (n = 11) diminished duodenal filling (P < 0.0001). PDC was 1.51 in the normal ePFT group versus 1.27 in the abnormal ePFT group (P = 0.01). No significant differences were found in terms of mean pancreatic AP diameter (21.8 vs. 19.8 cm), SIR (1.59 vs. 1.44), and A/V (1.08 vs. 1.01) between groups of normal/abnormal pancreatic exocrine function. CONCLUSION: Despite discrepancies between pancreatic exocrine function and the findings on standard MRI/MRCP, the S-MRCP findings are comparable to ePFT in the evaluation of chronic pancreatitis.

Hepatobiliary and pancreatic MRI and MRCP findings in patients with HIV infection.

OBJECTIVE: The purpose of this article is to describe the spectrum of MRI and MR cholangiopancreatography (MRCP) findings of hepatic, pancreatic, and biliary manifestations in patients with HIV infection. CONCLUSION: The spectrum of MRI and MRCP findings in HIV-infected patients includes acute or chronic hepatitis (or both), pancreatitis, cholangitis, acalculous cholecystitis, and biliary strictures that may resemble primary sclerosing cholangitis. The presence of segmental extrahepatic biliary strictures is characteristic of AIDS cholangiopathy.

Imaging of liver disease: comparison between quadruple-phase multidetector computed tomography and magnetic resonance imaging.

BACKGROUND AND AIM: To compare quadruple-phase multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for the assessment of focal and diffuse liver disease. METHODS: Quadruple-phase contrast-enhanced MDCT and MRI of 37 consecutive patients were retrospectively reviewed by two readers (R1 and R2). In patients with focal liver lesions, the gold standard was histopathology (n = 17) and/or long-term (>6 months) follow-up imaging (n = 27) or transarterial chemoembolization (n = 1). Diffuse liver disease was confirmed by histopathology in all patients, when present. RESULTS: Both readers identified 60 focal liver lesions on MDCT and 56 focal liver lesions on MRI. Gold standard diagnoses revealed 48 focal liver lesions in 25 patients. Diagnosis of malignant liver lesions revealed a sensitivity of 88% (R1) and 91% (R2) for MRI; 63% (R1) and 66% (R2) for MDCT; and a specificity of 75% (R1) and 79% (R2) for MRI; 50% (R1) and 64% (R2) for MDCT. MRI was superior to MDCT for the diagnosis of malignant focal liver lesions, when the mean areas under the alternative free-response receiver operating characteristic curves (A(Z)) were compared (MRI = 0.93 vs CT = 0.69), (P < 0.00001). Thirty-three patients had histopathologically confirmed diffuse liver disease. Overall diagnosis of diffuse liver disease revealed a sensitivity of 88% (R1) and 92% (R2) for MRI; 75% (R1) and 74% (R2) for MDCT; and a specificity of 100% for both modalities by both readers. CONCLUSIONS: MRI is superior for the assessment of malignant focal liver lesions and diffuse liver disease compared to quadruple-phase MDCT, and can be considered as primary diagnostic imaging modality for liver imaging.

Comparison between malignant and benign abdominal lymph nodes on diffusion-weighted imaging.

RATIONALE AND OBJECTIVES: The purpose of this study is to review the apparent diffusion coefficient (ADC) values of benign and metastatic abdominal lymph nodes on diffusion-weighted imaging (DWI). MATERIALS AND METHODS: Twenty-eight patients with a total of 40 benign (20 patients) and 16 malignant (8 patients) lymph nodes who underwent DWI MRI of the abdomen (b = 0.600) were enrolled in the study. ADC values of the lymph nodes were measured and comparison was made between benign and malignant groups. RESULTS: Mean ADC value of lymph nodes was 2.38 +/- 0.29 and 1.84 +/- 0.37 x 10(-3) mm(2)/sec in the benign and malignant groups, respectively. There was a significant statistical difference between the ADC values of benign and malignant lymph nodes (P < .0005). CONCLUSION: A wide range of ADC values exist in patients with metastatic abdominal lymph nodes, with a tendency of higher ADC values in benign lymph nodes.

Dynamic contrast enhanced MRI in the differential diagnosis of adrenal adenomas and malignant adrenal masses.

OBJECTIVE: To evaluate the value of dynamic MR imaging in the differential diagnosis of adrenal adenomas and malignant tumors, especially in cases with atypical adenomas. MATERIALS AND METHODS: Sixty-four masses (48 adenomas, 16 malignant tumors) were included in this prospective study. Signal loss of masses was evaluated using chemical shift MR imaging. Five dynamic series of T1-weighted spoiled gradient echo (FFE) images were obtained, with the acquisition starting simultaneously with i.v. contrast administration (0-100 s) followed by a T1-weighted FFE sequence in the late phase (5th minute). Contrast enhancement patterns in the early (25th second) and late (5th minute) phase images were evaluated. For the quantitative evaluation, signal intensity (SI)-time curves were obtained according to the SIs on the 0th, 25th, 50th 75th and 100th second. Also, the wash-in rate, maximum relative enhancement, time-to-peak, and wash-out of contrast at 100 s of masses in both groups were calculated. The statistical significance was determined by Mann-Whitney U test. To evaluate the diagnostic performance of the quantitative tests, receiver operating characteristic (ROC) analysis was performed. RESULTS: Chemical shift MR imaging was able to differentiate 44 out of 48 adenomas (91.7%) from non-adenomas. The 4 adenomas (8.3%) which could not be differentiated from non-adenomas by this technique did not exhibit signal loss on out-of-phase images. With a cut-off value of 30, SI indices of adenomas had a sensitivity of 93.8%, specificity of 100% and a positive predictive value of 100%. On visual evaluation of dynamic MR imaging, early phase contrast enhancement patterns were homogeneous in 75% and punctate in 20,83% of the adenomas; while patchy in 56.25% and peripheral in 25% of the malignant tumors. On the late phase images 58.33% of the adenomas showed peripheral ring-shaped enhancement and 10.41% showed heterogeneous enhancement. All of the malignant masses showed heterogeneous enhancement. At the 25th second, the SIs and wash-in rates of the adenomas were significantly higher than those of the malignant masses (p=0.010). Time-to-peak enhancement of the malignant masses was significantly longer than that of the adenomas. With a cut-off value of 52.85 s, the time-to-peak enhancement had 87.5% sensitivity and 80% specificity. CONCLUSION: Chemical shift MR has a high sensitivity and specificity in the differential diagnosis of adenomas and malignant adrenal masses. However, taking into consideration only the atypical adenomas, chemical shift MRI is of no diagnostic value. Although the diagnostic value of dynamic MRI is lower than chemical shift MRI, in the atypical cases contrast enhancement patterns and time-to-peak and wash-in rates derived from SI-time curve of dynamic MRI give are contributory to the results of chemical shift MRI.

Primary peritoneal carcinoma: computed tomography and magnetic resonance findings.

OBJECTIVE: To present computed tomography (CT) and magnetic resonance imaging (MRI) findings of primary peritoneal carcinoma (PPC) at initial presentation (IP) and recurrent disease (RD). METHODS: We studied 15 consecutive female patients (age range, 47-83 years; mean, 66.2 years) with pathologically proven PPC who underwent CT and/or MRI between July 2000 and December 2005. Preoperative radiological evaluation and postoperative follow-up was done with CT and/or magnetic resonance studies. All CT and MRI studies were evaluated retrospectively, independently, and blindly by 2 radiologists for the imaging findings of PPC. RESULTS: The imaging findings were as follows: ascites, 2 of 2 at IP, 9 of 10 at RD; peritoneal thickening and enhancement, 1 of 2 at IP, 9 of 10 at RD; peritoneal nodules or bulky mass lesions, 1 of 2 at IP, 8 of 10 at RD; lymph node involvement, 1 of 2 at IP, 3 of 10 at RD; and distant metastases, 1 of 10 at RD. CONCLUSION: Ascites, peritoneal thickening and enhancement, and peritoneal nodules or bulky mass lesions were the most frequent findings of PPC. Recurrent disease revealed similar findings compared with the IP.

Serial contrast-enhanced MRI of the pancreas: correlation with secretin-stimulated endoscopic pancreatic function test.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine the relationship between the pancreatic enhancement on serial contrast-enhanced MRI (CEMRI) and pancreatic exocrine function using the secretin-stimulated endoscopic pancreatic function test (ePFT). MATERIALS AND METHODS: A total of 30 patients with clinical symptoms consistent with chronic pancreatitis underwent CEMRI of the abdomen and ePFT within a 1- to 4-week interval. CEMRI was performed in arterial, early venous, and late venous phases. Secretin ePFT was performed with the measurement of HCO(3) concentration from the duodenal aspirates after secretin stimulation. Contrast enhancement ratio of the arterial phase to early venous phase was measured on CEMRI (SIRa/SIRv). A three-point evaluation system was used for grading the HCO(3) concentration and the enhancement ratio on MRI. For the significance of correlation, kappa statistics was used. Sensitivity and specificity of CEMRI was determined for the diagnosis of early chronic pancreatitis accepting ePFT as a reference. RESULTS: Twenty patients had identical scores on both secretin ePFT and CEMRI. Ten patients revealed discrepancy in scores. Kappa statistics revealed moderate agreement between MRI and ePFT (kappa = 0.44). Sensitivity and specificity values for the diagnosis of pancreatitis were 82% and 57%, respectively. Positive predictive value was 56%, and negative predictive value was 86%. CONCLUSION: The results of our data indicate that serial CEMRI is an appropriate imaging technique to rule out early chronic pancreatitis. However, secretin-stimulated imaging or ePFT may still be needed for the definite diagnosis of pancreatic exocrine dysfunction.

Contrast agents for MR imaging of the liver.

Imaging of the liver is performed most often to detect and characterize focal liver lesions. MR imaging has been the method of choice to assess focal liver lesions accurately. Nonspecific intravenous contrast agents have been used for routine abdominal MR imaging protocols including liver imaging. Over the last 10 to 15 years new contrast agents have been developed that combine the excellent contrast resolution of MR imaging with improved tissue specificity. This article reviews various contrast agents that are in clinical use for liver MR imaging and discusses their potential clinical role.

Renal-related perinephric fluid collections: MRI findings.

We retrospectively reviewed MR studies on 10 patients with renal-related perinephric fluid collections who underwent MRI in three institutions between January 2001 and August 2004. All patients underwent MRI of the abdomen and T1-weighted, T2-weighted and serial contrast-enhanced images, including delayed-phase contrast-enhanced images 10-12 min after contrast injection, were obtained. Perinephric fluid collections in 5 patients revealed MRI findings of simple fluid content (i.e., hypointense on T1-weighted images and hyperintense on T2-weighted images). In another 5 patients, a complex perinephric fluid content (i.e., mixed hyper/hypointense on T1-weighted images and mixed hypo/hyperintense on T2-weighted images compatible with blood breakdown products and pus) was observed. In 5 patients, contrast extravasation on late-phase images that was compatible with urine leak was demonstrated. Our results suggest that MRI may determine the content of perinephric fluid collections on noncontrast T1-weighted and T2-weighted images and that contrast extravasation on late-phase images is associated with urine extravasation from renal collecting systems.

Future horizons in MR imaging.

In this article, we defined the major areas of active research in clinical MR imaging. Further increases in the number of parallel coils within an imaging array and in advances in parallel imaging pulse sequences and postprocessing will lead to further reductions in imaging time analogous to the impact of multidetector CT on helical CT. The synergism between parallel and high-field imaging will aid the development of high-field imaging. The combined dynamic and hepatic parenchymal enhancement of new contrast agents that have or may soon receive FDA approval will enable improved detection and characterization of liver lesions. The lymphotropic SPIO agents will remain an active area of clinical research to further assess their role in oncologic staging. Molecular imaging contrast research using magnetic particles and MR microscopy will continue to flourish. Screening examinations by MR imaging will re-main an area of research for the short- and intermediate term, with the final outcome dependent more on socioeconomic costs than the underlying capability of achieving high-quality screening studies.

Primary epiploic appendagitis: MRI findings.

Primary epiploic appendagitis (PEA) occurs secondary to inflammation of an epiploic appendage, and is considered to be a rare cause of acute abdomen. In this case report, we describe the magnetic resonance imaging (MRI) findings of PEA correlated with computed tomographic (CT) findings. MRI findings included an oval shaped fat intensity mass with a central dot on T1- and T2-weighted images, which possessed an enhancing rim on postgadolinium T1-weighted fat saturated images. The lesion was best visualized on postcontrast T1-weighted fat saturated images. MRI findings of PEA should be considered in the differential diagnosis with the other causes of acute abdominal pain.

Assessment of the anomalous pulmonary circulation by dynamic contrast-enhanced MR angiography in under four seconds.

The purpose of this study was to demonstrate the initial results of the dynamic contrast-enhanced MRA in under four seconds in the assessment of anomalous pulmonary circulation. We performed dynamic contrast enhanced MRA on ten patients with a temporal resolution of 2-3 sec for each phase. Five patients had pulmonary vascular anomaly and five patients had reconstructed pulmonary circulation. On nine patients catheter angiography was performed for the correlation. Dynamic contrast-enhanced MRA successfully demonstrated congenital pulmonary vascular anomalies and the pathway of anomalous pulmonary circulation in our series. With the improved temporal and spatial resolution, the dynamic contrast-enhanced MRA can be used in children and infants for the assessment of congenital vascular disease.

MR imaging of infective liver lesions.

This article discusses MR imaging of infective liver lesions including pyogenic liver abscesses, amebic liver abscesses, echinococcal disease, hepatic fungal abscesses, granulomatous hepatic infections, schistosomiasis, and fascioliasis.

Juxtapapillary diverticulum: findings on CT and MRI.

The purpose of this study was to evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) features of juxtapapillary diverticulum. CT and/or MRI examinations of 12 patients were evaluated. The size, location of the diverticula and imaging findings of associated pancreaticobiliary disease were assessed. On CT, oral contrast air level was the characteristic imaging feature. On MRI, T2-weighted images demonstrated the air fluid level with hyperintense fluid and signal void air level above. Associated imaging findings were dilated common bile duct (CBD), cholecystitis, cholecystolithiasis and chronic pancreatitis.

Hepatic adenomatosis: MRI demonstration with the use of superparamagnetic iron oxide.

This case report describes a case of a 38-year-old woman with hepatic adenomatosis. MRI revealed five hyperintense nodular liver lesions on T1-weighted images which were hypo-isointense with the liver parenchyma on T2-weighted images. Serial gadolinium-enhanced images did not reveal distinctive imaging findings. With the use of superparamagnetic iron oxide (SPIO) particles, hyperintense adenomas revealed signal loss on T1-weighted images after SPIO. Two subcapsular adenomas were resected based on MRI findings and histopathology confirmed MRI diagnosis.

Hepatic angiomyolipoma: demonstration by out of phase MRI.

Hepatic angiomyolipoma is a rare liver pathology. In this case report, we describe MRI features of a hepatic angiomyolipoma with a high fat content, which was indeterminate on CT. In phase and out of phase T1-weighted spoiled gradient echo technique, T2-weighted fat suppressed fast spin echo technique and dynamic enhanced T1-weighted in phase gradient echo technique were used. Out of phase gradient echo sequence was the most sensitive technique identifying the fat content of the lesion in its mixed tissue composition.

The effect of prior sphincterotomy on the secretin-stimulated magnetic resonance cholangiopancreatography (s-MRCP).

RATIONALE AND OBJECTIVES: A lack of pancreatic duct compliance and decreased duodenal filling on secretin-stimulated magnetic resonance cholangiopancreatography (s-MRCP) has been noted in patients with chronic pancreatitis. Whether endoscopic sphincterotomy can affect pancreatic duct compliance and duodenal filling on diagnostic s-MRCP is unknown. MATERIALS AND METHODS: A retrospective review of patients referred to the authors' clinic from December 2006 to December 2007 was performed. Those patients with no evidence of chronic pancreatitis who underwent s-MRCP were studied. Findings on s-MRCP were analyzed, specifically noting change in pancreatic duct diameter size from baseline to maximum dilation and duodenal filling after secretin administration (0.2 microg/kg intravenous dose of human secretin). RESULTS: Of the 34 patients studied, 12 underwent endoscopic sphincterotomy, and 22 had intact sphincters of Oddi. In the sphincterotomy group, there was a mean change of 0.2 cm (range, 0.0-0.4 cm), while in the nonsphincterotomy group, the mean change was 0.9 cm (range, 0.3-2.0 cm) after secretin administration. The difference was significant (P < .005). CONCLUSION: Endoscopic sphincterotomy significantly decreases pancreatic duct dilation in response to secretin on s-MRCP. However, further studies are required to determine the effect sphincterotomy has on the amount of duodenal filling and the rate at which duodenal filling occurs.

Pancreatic diffusion-weighted imaging (DWI): comparison between mass-forming focal pancreatitis (FP), pancreatic cancer (PC), and normal pancreas.

PURPOSE: To compare diffusion-weighted imaging (DWI) findings and the apparent diffusion coefficient (ADC) values of pancreatic cancer (PC), mass-forming focal pancreatitis (FP), and the normal pancreas. MATERIALS AND METHODS: DWI (b = 0 and 600 seconds/mm(2)) findings of 14 patients with mass-forming FP proven by histopathology and or clinical follow-up, 10 patients with histopathologically-proven PC, and 14 subjects with normal pancreatic exocrine function and normal imaging findings were retrospectively evaluated. ADC values of the masses, the remaining pancreas, and the normal pancreas were measured. RESULTS: On b = 600 seconds/mm(2) DWI, mass-forming FP was visually indistinguishable from the remaining pancreas whereas PC was hyperintense relative to the remaining pancreas. The mean ADC value of PC (1.46 +/- 0.18 mm(2)/second) was significantly lower than the remaining pancreas (2.11 +/- 0.32 x 10(-3) mm(2)/second; P < 0.0001), mass-forming FP (2.09 +/- 0.18 x 10(-3) mm(2)/second; P < 0.0001), and pancreatic gland in the control group (1.78 +/- 0.07 x 10(-3) mm(2)/second; P < 0.0005). There was no significant difference of ADC values between the mass-forming focal pancreatitis and the remaining pancreas (2.03 +/- 0.2 x 10(-3) mm(2)/second; P > 0.05). CONCLUSION: Differences on DWI may help to differentiate PC, mass-forming FP, and normal pancreas from each other.