Hepatocellular carcinoma: detection with gadolinium- and ferumoxides-enhanced MR imaging of the liver.

PURPOSE: To test the hypothesis that the accuracy of gadolinium- and ferumoxides-enhanced magnetic resonance (MR) imaging is different in small (< or =1.5-cm) and large (>1.5-cm) hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Forty-three consecutive patients with chronic liver disease were enrolled in this study. The imaging protocol included unenhanced breath-hold T1-weighted fast field-echo sequences, unenhanced respiratory-triggered T2-weighted turbo spin-echo (SE) sequences, dynamic gadolinium-enhanced T1-weighted three-dimensional turbo field-echo sequences, and ferumoxides-enhanced T2-weighted turbo SE sequences. Images of each sequence and two sets of sequences (ferumoxides set and gadolinium set) were reviewed by four observers. The ferumoxides set included unenhanced T1- and T2-weighted images and ferumoxides-enhanced T2-weighted turbo SE MR images. The gadolinium set included unenhanced T1- and T2-weighted images and dynamic gadolinium-enhanced three-dimensional turbo field-echo MR images. In receiver operating characteristic (ROC) curve analysis, the sensitivity and accuracy of the sequences were compared in regard to the detection of all, small, and large HCCs. RESULTS: Imaging performance was different with gadolinium- and ferumoxides-enhanced images in the detection of small and large HCCs. For detection of small HCCs, the sensitivity and accuracy with unenhanced and gadolinium-enhanced imaging (gadolinium set) were significantly (P =.017) superior to those with unenhanced and ferumoxides-enhanced imaging (ferumoxides set). The area under the composite ROC curves, or A(z), for the gadolinium set and the ferumoxides set was 0.97 and 0.81, respectively. For large HCC, the ferumoxides set was superior compared with the gadolinium set, but this difference was not statistically significant. Analysis of all HCCs demonstrated no significant differences for gadolinium- and ferumoxides-enhanced imaging. CONCLUSION: For the detection of early HCC, gadolinium-enhanced MR imaging is preferred to ferumoxides-enhanced MR imaging because the former demonstrated significantly greater accuracy in the detection of small HCCs.     

Focal hepatic lesions: detection and characterization with combination gadolinium- and superparamagnetic iron oxide-enhanced MR imaging

PURPOSE: To compare gadolinium- and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging for detection and characterization of focal hepatic lesions when different contrast agent administration sequences are used. MATERIALS AND METHODS: Unenhanced, dynamic gadolinium-enhanced, and SPIO-enhanced hepatic MR images were obtained in 134 patients. SPIO-enhanced MR imaging was performed immediately after gadolinium-enhanced dynamic MR imaging in 50 patients, 1 day after gadolinium-enhanced dynamic MR imaging in 40 patients, and before gadolinium-enhanced dynamic MR imaging in 44 patients. Two radiologists independently reviewed the gadolinium image set (unenhanced and gadolinium-enhanced dynamic MR images) and the SPIO image set (unenhanced and SPIO-enhanced MR images) in random order. Lesion detection sensitivity and lesion characterization accuracy were compared by analyzing the area under the receiver operating characteristic curve (Az). RESULTS: Overall lesion detection accuracy for pooled data was significantly higher with the SPIO set (Az = 0.903) than with the gadolinium set (Az = 0.857) (P <.05). When hypovascular lesions were excluded, the detection rate was similar with the two sets. When hepatocellular carcinomas were excluded, the detection rate was significantly higher with the SPIO set (P <.01). Readers were more accurate in differentiating benign from malignant lesions with the gadolinium set (Az = 0.915) than with the SPIO set (Az = 0.847) (P <.01). Detection accuracy tended to be better with the images obtained after the second contrast agent was used. CONCLUSION: Hypovascular lesion detection was better with SPIO-enhanced MR images than with gadolinium-enhanced MR images. Detection and characterization of hypervascular lesions were improved with gadolinium-enhanced MR images.     

Esophageal varices in patients with cirrhosis: multidetector CT esophagography--comparison with endoscopy

PURPOSE: To evaluate the use of multidetector computed tomographic (CT) esophagography to grade esophageal varices and differentiate between varices at low risk and those at high risk for bleeding, with endoscopy as the reference standard. MATERIALS AND METHODS: This study was approved by the institutional review board; all subjects gave informed consent. Ninety patients with cirrhosis (65 men, 25 women; mean age, 54.8 years; range, 21-77 years) were prospectively enrolled and underwent endoscopy and CT esophagography. Esophageal varices were graded independently at endoscopy by two endoscopists. CT esophagograms were interpreted retrospectively with a four-point scale by two radiologists blinded to other findings. Interobserver agreement between each radiologist and endoscopist was determined; endoscopic and CT esophagographic grades of esophageal varices were correlated. Radiologist performance for differentiation between low- and high-risk varices for bleeding on the basis of morphology at endoscopy was evaluated with receiver operating characteristic analysis. Patients were interviewed to determine acceptance at both examinations. RESULTS: Thirty-seven of 90 patients had grade 0, 23 had grade 1, 18 had grade 2, and 12 had grade 3 esophageal varices. Thus, 60 patients were determined to be in a low-risk group and 30 in a high-risk group for variceal bleeding at endoscopy. There was almost perfect agreement in grading esophageal varices between endoscopists. There was close correlation (P < .001) and substantial agreement between endoscopic and CT esophagographic grades. Radiologist performance for differentiating between low- and high-risk varices was 0.931-0.958 (area under receiver operating characteristic curve). Patient interview results revealed that CT esophagography had better acceptance than did endoscopy (P < .001). CONCLUSION: Use of CT esophagography allows grading of esophageal varices and differentiation between low- and high-risk varices and shows better patient acceptance than does endoscopy.     

Preoperative detection of malignant hepatic tumors: comparison of combined methods of MR imaging with combined methods of CT

OBJECTIVE: We compared radiologists' performance on combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR imaging with their performance on helical CT during arterial portography (CTAP) and biphasic CT during hepatic arteriography (CTHA) for the preoperative detection of malignant hepatic tumors. SUBJECTS AND METHODS: MR images and CT scans obtained in 33 patients were retrospectively analyzed. Images of the liver were reviewed on a segment-by-segment basis; a total of 261 segments with 39 hepatocellular carcinomas and 21 metastases were independently reviewed by three radiologists who were invited from outside institutions. Unenhanced and gadolinium-enhanced MR images were reviewed first, then ferumoxides-enhanced MR images were added for combined review. CTAP images and biphasic CTHA images were reviewed together. RESULTS: Sensitivity for the detection of hepatic tumors was analogous for combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR images (86%) and for combined CTAP images and biphasic CTHA images (87%). Specificity was higher with MR images (95%, p < 0.01) than with CT images (91%). Radiologists' performances were improved (Az = 0.962, p = 0.0502) by combining ferumoxides-enhanced MR images with unenhanced and gadolinium-enhanced MR images (Az = 0.950), and were analogous for combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR images and for combined CTAP images and biphasic CTHA images (Az = 0.959). CONCLUSION: Radiologists' performances on combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR imaging compared with their performances on combined helical CTAP and biphasic CTHA are analogous for the preoperative detection of malignant hepatic tumors. Such a dedicated combination of MR imaging may obviate the need for more invasive angiographically assisted helical CT for the preoperative detection of malignant hepatic tumors.     

Esophageal varices: evaluation with transesophageal MR imaging--initial experience

PURPOSE: To prospectively use transesophageal magnetic resonance (MR) imaging to determine the morphologic and hemodynamic characteristics of esophageal varices. MATERIALS AND METHODS: The study was approved by the ethics committee. All patients gave written informed consent. Forty-two patients (29 men, 13 women; mean age, 58 years +/- 11 [standard deviation]) with esophageal varices that were recently demonstrated at endoscopy were included in the study. MR imaging was performed by using a receiver probe that was placed in the esophagus. Black-blood T2-weighted MR images were obtained with cardiac triggering and navigator gating of the right hemidiaphragm. On these images, the maximal diameter, minimal diameter, and surface area of the largest esophageal varix were measured. Periesophageal and paraesophageal varices were recorded. A hemodynamic examination was performed in the last 21 patients to undergo MR imaging, which was used to obtain measurements of flow velocity and rate before and after intravenous injection of 50 mug of octreotide or a placebo. A Kruskal-Wallis test was used to assess differences in the diameter and surface area of the varices according to endoscopic grade. Hemodynamic changes observed after octreotide or placebo injection were compared by using an analysis of variance and a 95% confidence interval. RESULTS: Periesophageal varices were observed in 36 patients, and paraesophageal varices were observed in 32 patients. The minimal diameter, maximal diameter, and surface area of the esophageal varices at MR imaging differed significantly according to endoscopic grade (P < .001). In the periesophageal varices, the velocity and flow changes caused by octreotide differed significantly from those caused by the placebo (P < .001). A decrease in velocity (mean velocity change, -2.766 cm.sec(-1)) and flow (mean flow change, -0.455 mL.sec(-1)) was noted after octreotide injection, but no significant change in velocity (mean velocity change, 0.252 cm.sec(-1)) or flow (mean flow change, 0.018 mL.sec(-1)) was noted after placebo injection. The surface area of the varices did not change significantly after octreotide (mean change, -0.771 mm2) or placebo (mean change, -0.015 mm2) injection. CONCLUSION: Transesophageal MR imaging is a feasible method to assess the morphologic and hemodynamic characteristics of esophageal varices before and after pharmacologic treatment.     

MR angiography in portal hypertension: detection of varices and imaging techniques

This study was performed to compare time-of-flight MR angiography in detecting varices with conventional portography and endoscopy in patients with chronic liver disease and to compare MR tomographic images with projection angiograms. In eight patients findings on conventional arterial portography (considered the gold standard) were compared with the MR findings. Varices were graded by size and extent on a scale of 0-3. Splenic varices were detected in all patients by MR but were scored larger on portography in 6 (55%) of 11 comparisons. All left gastric varices were identified at MR and were rated within one grade of those seen at portography. All esophageal varices were identified at MR. Among 12 patients with upper endoscopy, MR rated varices significantly (p less than 0.05) larger than endoscopy in 8 (67%) of 12 comparisons. Varices were detected in two patients on MR that were not seen endoscopically. Extraperitoneal varices were identified in six (75%) of eight patients on MR and were only visualized in one patient at portography. Varices were equally well detected using either axial or coronal images. No significant difference existed when tomographic images were compared with projection images. Time-of-flight MR angiography is a valid technique for noninvasive imaging of abdominal varices. Tomographic single slice images are generally as good as projection images except possibly in the demonstration of extraperitoneal varices.     

Detection of malignant hepatic tumors: comparison of gadolinium-and ferumoxide-enhanced MR imaging

OBJECTIVE: The purpose of our study was to compare how well gadolinium-enhanced and ferumoxide-enhanced MR imaging reveal malignant hepatic tumors. SUBJECTS AND METHODS: Both gadolinium-enhanced and ferumoxide-enhanced MR imaging were separately performed in 53 patients with a total of 87 malignant hepatic tumors (57 hepatocellular carcinomas, 28 metastases, two cholangiocarcinomas). Thirty-one of the 53 patients had hepatic cirrhosis. Images were reviewed by three independent off-site observers. Observer performance was evaluated by means of sensitivity, specificity, and receiver operating characteristic curve analyses. RESULTS: Gadolinium-enhanced MR imaging outperformed ferumoxide-enhanced MR imaging in sensitivity (81% versus 62%, p < 0.01) for malignant-tumor detection. Specificity was comparable (94%) between the two types of MR imaging. Area under receiver operating characteristic curve (A(z)) value was significantly higher with gadolinium-enhanced MR imaging than with ferumoxide-enhanced MR imaging in patients overall (A(z) = 0.896 versus 0.805, p < 0.001), in patients with cirrhosis (A(z) = 0.907 versus 0.807, p < 0.001), and in patients without cirrhosis (A(z) = 0.899 versus 0.834, p < 0.01). The superiority was enhanced in the subset of patients with cirrhosis. CONCLUSION: Gadolinium-enhanced MR imaging outperforms ferumoxide-enhanced MR imaging in revealing malignant hepatic tumors. Gadolinium-enhanced MR imaging is recommended, particularly for patients with cirrhosis.     

菲立磁增强MRI对局灶性肝病的诊断价值:与螺旋CT对比的ROC曲线分析

目的 :对比分析菲立磁增强扫描与螺旋CT增强扫描对局灶性肝病的诊断价值。方法 :收集经本院完成螺旋CT增强扫描及菲立磁增强MRI扫描且临床、手术病理证实局灶性肝病 2 6例 5 7个病灶 ,采用分组盲法ROC曲线分析对比评价菲立磁增强MRI与螺旋CT增强扫描对局灶性肝病的诊断价值。结果 :联合分析平扫 +菲立磁增强MRI对病灶检出最好 ,与其它三组比较有显著性差异。对病灶定性 ,平扫 +菲立磁增强MRI组ROC曲线下面积Az 值最大为 0 92 6 0 ,准确性为 86 .8% ,差异有显著性 ,P <0 .0 5。螺旋CT增强扫描、MRI平扫及单独分析菲立磁MRI等三种方法之间差异无显著性 (P >0 .0 5 )。结论 :菲立磁增强MRI肝成像无论病灶的检出及定性诊断价值均高于螺旋CT增强扫描。联合分析平扫+菲立磁MRI较单独分析SPIO能明显改善病灶的检出能力及定性诊断能力。     

MR imaging follow-up after percutaneous radiofrequency ablation of renal cell carcinoma: findings in 18 patients during first 6 months

PURPOSE: To prospectively evaluate the magnetic resonance (MR) imaging findings seen within the first 6 months after radiofrequency (RF) thermal ablation of renal cell carcinoma (RCC). MATERIALS AND METHODS: After providing written informed consent, 18 patients (17 men, one woman; mean age, 71.2 years) with RCC underwent MR imaging-guided percutaneous RF thermal ablation, which was performed by using protocols approved by a comprehensive cancer center protocol committee and the institutional review board for human investigation. The study was Health Insurance Portability and Accountability Act compliant. Follow-up unenhanced T2-weighted MR images and unenhanced and gadolinium-enhanced T1-weighted MR images were acquired immediately, 2 weeks, 3 months, and 6 months after ablation. Thermal ablation zone size was analyzed, and contrast-to-noise ratios (CNRs) were calculated from the signal amplitudes of the thermal ablation zone, perirenal fat, and normal renal cortex on the MR images. Statistical analyses were performed by using the paired Student t test. P < .05 was considered to indicate statistical significance. RESULTS: The mean follow-up time was 16.1 months (range, 6.0-41.2 months). The mean sizes of the thermal ablation zones were 6.8, 7.0, 6.1, and 4.7 cm2, respectively, at immediate, 2-week, 3-month, and 6-month follow-up MR imaging examinations. Thermal ablation zones were uniformly hypointense and had a surrounding bright rim on T2-weighted images and were predominantly hyperintense on T1-weighted images. Thin rim enhancement with central hypointensity was noted on the gadolinium-enhanced images. Gadolinium-enhanced T1-weighted and unenhanced T2-weighted MR images showed significantly higher CNRs than unenhanced T1-weighted MR images. Residual tumor was detected after RF thermal ablation in two cases and was best seen on unenhanced T2-weighted and gadolinium-enhanced T1-weighted MR images. CONCLUSION: After initially increasing in size within the first 2 weeks, renal RF thermal ablation zones involuted during the remainder of the MR imaging follow-up period.     

Evaluation of the longitudinal tumor extent of bile duct cancer: value of adding gadolinium-enhanced dynamic imaging to unenhanced images and magnetic resonance cholangiography

OBJECTIVE: To determine the added value of gadolinium-enhanced dynamic magnetic resonance (MR) images compared with unenhanced and MR cholangiography (MRC) images, to evaluate the longitudinal extension of bile duct cancer. MATERIALS AND METHOD: Thirty-three patients with hilar cholangiocarcinoma or common duct cancer who had undergone MRC, unenhanced, and gadolinium-enhanced dynamic MR images and surgery were included in this study. Two experienced radiologists independently reviewed 2 image sets in 2 steps, that is, the MRC set (unenhanced and MRC) and the combined image set (MRC set with dynamic images). At each step, the readers determined the tumor status according to the Bismuth-Corlette classification. The readers assigned their confidence levels on a 5-point scale regarding whether the tumor involved the secondary confluence of the bile duct and the intrapancreatic common bile duct. The radiologists' diagnostic confidence of the 2 image sets was analyzed using receiver operating characteristic analysis. RESULTS: Receiver operating characteristic analysis showed higher areas under the curve values when the combined image set was interpreted (0.990 +/- 0.017 for reader 1 and 0.951 +/- 0.027 for reader 2) than when the MRC set was interpreted (0.982 +/- 0.017 for reader 1 and 0.902 +/- 0.038 for reader 2); however, the difference was not statistically significant for either reader (P > 0.05). In addition, regarding evaluation of the tumor status according to the Bismuth-Corlette classification, the overall accuracy was higher for the combined image set than for the MRC set alone, but the difference was not significant (P > 0.05). When dynamic images were added to the MRC images, interobserver agreement improved from 0.72 to 0.84. CONCLUSIONS: The addition of contrast-enhanced dynamic images to unenhanced and MRC images did not significantly improve the diagnostic accuracy for assessment of the longitudinal extent of bile duct cancer.     

Small hepatocellular carcinoma treated with percutaneous RF ablation: MR imaging follow-up.

OBJECTIVE: The purpose of our study was to determine the usefulness of MR imaging in the follow-up evaluation of small hepatocellular carcinoma lesions treated with RF ablation. SUBJECTS AND METHODS: The study group included 37 patients with a single hepatocellular carcinoma lesion less than 3 cm in diameter. A strict protocol required follow-up MR imaging every 6 months after RF treatment. At each follow-up visit, the findings on unenhanced and dynamic gadolinium-enhanced MR images were correlated with those on contrast-enhanced CT images and with results of fine-needle aspiration biopsy. In five patients who underwent surgical resection after the 6-month follow-up examination, comparison with histologic findings of surgical specimens was also performed. RESULTS: Correct diagnosis of complete or partial tumor necrosis was made in 32 (86%) of the 37 patients with the use of unenhanced and dynamic gadolinium-enhanced MR images. Hypointensity on T2-weighted images and loss of enhancement on dynamic MR images corresponded to completely necrotic lesions in all patients. Conversely, intratumoral regions of hyperintensity on T2-weighted images and enhancement on dynamic MR images did not always correlate to residual viable tumor. MR imaging and CT findings agreed in the evaluation of therapeutic response in all patients. CONCLUSION: Our experience confirms that MR imaging is useful for evaluating the effectiveness of RF therapy in achieving tumor regression.     

Renal MR angiography at 1.0 T: three-dimensional (3D) phase-contrast techniques versus gadolinium-enhanced 3D fast low-angle shot breath-hold imaging.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic usefulness of three different MR angiographic techniques at 1.0 T. SUBJECTS AND METHODS: In 22 patients with renal artery stenosis confirmed at intraarterial catheter angiography, we also performed unenhanced and gadolinium-enhanced three-dimensional phase-contrast MR angiography and gadolinium-enhanced single breath-hold three-dimensional fast low-angle shot MR angiography. We determined circulation time to optimize signal acquisition in gadolinium-enhanced breath-hold MR angiography after bolus injection of contrast material. RESULTS: Sensitivity, defined as the detection of a hemodynamically significant stenosis (>50% luminal narrowing), was 85% for enhanced phase-contrast MR angiography, 91% for gadolinium-enhanced MR angiography, and 95% for unenhanced phase-contrast MR angiography. The combination of unenhanced phase-contrast MR angiography and gadolinium-enhanced MR angiography yielded 100% sensitivity for hilar artery stenoses. There were 13 false-positive findings with unenhanced phase-contrast MR angiography, 10 with enhanced phase-contrast MR angiography, and four with gadolinium-enhanced MR angiography (specificity: 38%, 52%, and 79%, respectively). Accessory renal arteries were not seen on unenhanced or enhanced phase-contrast MR angiography (0/8 patients) but were detected with gadolinium-enhanced MR angiography in five of the eight patients. Interobserver agreement (kappa = .62) was best with gadolinium-enhanced MR angiography. The quality of the images was unsatisfactory for adequate evaluation of segmental renal arteries with all three MR angiographic techniques. CONCLUSION: A combination of unenhanced phase-contrast MR angiography and gadolinium-enhanced MR angiography at 1.0 T proved useful as a screening protocol for renal artery stenosis.     

Ferumoxides-enhanced double-echo T2-weighted MR imaging in differentiating metastases from nonsolid benign lesions of the liver

PURPOSE: To investigate whether ferumoxides-enhanced double-echo T2-weighted magnetic resonance (MR) imaging alone can allow differentiation of metastases from benign lesions in the noncirrhotic liver. MATERIALS AND METHODS: At retrospective review of files and images, 60 lesions (22 metastases, 20 hemangiomas, and 18 cysts) were identified in 42 patients. All fast spin-echo T2-weighted MR images obtained before and after administration of ferumoxides with short (80-90 msec) and long (180-250 msec) echo times (TEs) were acquired with a 1.5-T system. Differences in lesion-to-liver signal intensity ratio between images obtained with long and short TEs were calculated. Data from all 60 lesions were entered into a receiver operating characteristic analysis. Three independent readers scored their observations of each lesion with a confidence level of 1-5. The diagnostic accuracy of each analysis method was determined by calculating the area under each reader-specific receiver operating characteristic curve. Interobserver agreement was calculated with the use of chance-corrected kappa statistics. Relative sensitivity, specificity, and accuracy of characterizing benign lesions with each method were calculated. RESULTS: Markedly low signal intensity and lesion-to-liver ratio on ferumoxides-enhanced images were observed with hemangioma. The difference of lesion-to-liver ratio between long and short TEs on ferumoxides-enhanced images was significantly different from that of unenhanced images and that of metastases or cysts. Interobserver agreement was good to excellent. Ferumoxides-enhanced images (with short and long TEs) showed significantly higher diagnostic accuracy than that of unenhanced images (with short or short and long TEs). Ferumoxides-enhanced images showed similar sensitivity, specificity, and accuracy when all images were reviewed together. CONCLUSION: Ferumoxides-enhanced T2-weighted MR images appear useful in differentiating metastases from benign (nonsolid) lesions in the liver.     

Ovarian lesions: detection and characterization with gadolinium-enhanced MR imaging at 1.5 T

Magnetic resonance (MR) imaging for detection and characterization of ovarian masses was assessed in 33 patients with a total of 60 lesions. Lesions were characterized prospectively as benign or malignant by using T2-weighted MR images and unenhanced and gadolinium-enhanced T1-weighted MR images. MR imaging findings were compared with results of surgical laparotomy performed for staging of lesions. When malignancy was suspected, staging with MR imaging was performed. MR imaging demonstrated 57 of 60 (95%) surgically proved ovarian masses (34 of 36 were benign, 23 of 24 were malignant). Five significant primary criteria and four ancillary criteria for malignancy were established. For all MR pulse sequences combined, characterization of either type of lesion was correct in 84% of cases (48 of 57) when the five primary criteria were used and 95% (54 of 57) were correct when the four ancillary criteria were added. With gadolinium-enhanced images, correct characterization of malignant lesions increased from 56% to 78% with use of the five primary criteria and from 83% to 100% with use of both sets of criteria. Malignancies were correctly staged with MR imaging in 12 of 16 patients. Staging accuracy was 63% with unenhanced images and 75% with the addition of enhanced images.     

T2-weighted MR imaging in the assessment of cirrhotic liver

PURPOSE: To assess if T2-weighted magnetic resonance (MR) imaging provides added diagnostic value in combination with dynamic gadolinium-enhanced MR imaging in the detection and characterization of nodular lesions in cirrhotic liver. MATERIALS AND METHODS: Two readers retrospectively and independently analyzed 54 MR imaging studies in 52 patients with cirrhosis. In session 1, readers reviewed T1-weighted and dynamic gadolinium-enhanced images. In session 2, readers reviewed T1-weighted, dynamic gadolinium-enhanced, and respiratory-triggered T2-weighted fast spin-echo images. Readers identified and characterized all focal lesions by using a scale of 1-4 (1, definitely benign; 4, definitely malignant). Multireader correlated receiver operating characteristic (ROC) analysis was employed to assess radiologist performance in session 2 compared with session 1. The difference in the areas under the ROC curves for the two sessions was tested. In a third session, readers assessed conspicuity of biopsy-proved lesions on T2-weighted MR images by using a scale of 1-3 (1, not seen; 3, well seen) and identified causes of reduced conspicuity. RESULTS: Two additional benign lesions were detected by each reader in session 2. Fifty-five lesions had pathologic verification, including 32 malignant, three high-grade dysplastic, and 20 benign nodules. There was no significant difference in the area under the ROC curves between the two sessions (P =.48). Thirty-two lesions were inconspicuous on T2-weighted MR images because of parenchymal heterogeneity, breathing artifacts (particularly in patients with ascites), and lesion isointensity with liver parenchyma. T2-weighted MR imaging was useful in the evaluation of cysts and lymph nodes. CONCLUSION: T2-weighted MR imaging does not provide added diagnostic value in the detection and characterization of focal lesions in cirrhotic liver.     

Detection of hepatocellular carcinoma arising in cirrhotic livers: comparison of gadolinium- and ferumoxides-enhanced MR imaging.

OBJECTIVE: We prospectively compared the detectability of hepatocellular carcinoma (HCC) arising in cirrhotic livers using dynamic gadolinium-enhanced fast low-angle shot (FLASH), ferumoxides-enhanced T2-weighted turbo spin-echo, and ferumoxides-enhanced T2*-weighted FLASH MR imaging. SUBJECTS AND METHODS: Fifty-three patients with HCC (32 men and 21 women) who were 33-86 years old (mean, 63 years old) were enrolled in a prospective MR study to assess hepatic lesions using both gadopentetate dimeglumine and ferumoxides. Dynamic gadolinium-enhanced imaging was obtained before and 30, 60, and 180 sec after rapid bolus injection of gadopentetate dimeglumine (0.1 mmol/kg). Ferumoxides-enhanced T2-weighted turbo spin-echo imaging and ferumoxides-enhanced T2*-weighted FLASH imaging were performed between 30 min and 2 hr after i.v. infusion of ferumoxides (10 micromol/kg). Images were analyzed qualitatively and quantitatively. A receiver operating characteristic curve study was performed to compare the diagnostic value of gadolinium-enhanced imaging with that of ferumoxides-enhanced imaging for the detection of HCC. RESULTS: Quantitative analysis revealed a significantly higher percentage of signal-intensity loss and higher liver-lesion contrast-to-noise ratio on ferumoxides-enhanced T2*-weighted FLASH imaging than on ferumoxides-enhanced T2-weighted turbo spin-echo imaging. The percentage of signal-intensity loss and liver-lesion contrast-to-noise ratio on ferumoxides-enhanced images was significantly higher in patients with mild liver cirrhosis (Child's class A) than in patients with severe liver cirrhosis (Child's class C). Qualitative analysis showed that dynamic gadolinium-enhanced images revealed significantly higher lesion conspicuity than did ferumoxides-enhanced T2-weighted turbo spin-echo images. According to receiver operating characteristic analysis, dynamic gadolinium-enhanced FLASH imaging achieved the highest sensitivity, and ferumoxides-enhanced T2*-weighted FLASH imaging was the second most sensitive. We found that ferumoxides-enhanced turbo spin-echo imaging was the least valuable technique for revealing HCC lesions. Gadolinium-enhanced imaging revealed more HCC lesions than did ferumoxides-enhanced imaging, particularly for lesions smaller than 2 cm in diameter. CONCLUSION: Ferumoxides-enhanced imaging revealed fewer findings, such as lesion conspicuity of HCCs arising in cirrhotic livers, than did gadolinium-enhanced FLASH imaging.     

Chronic hepatitis: correlation of early patchy and late linear enhancement patterns on gadolinium-enhanced MR images with histopathology initial experience

The purposes of our study were to describe the early and late enhancement patterns of the liver on gadolinium-enhanced dynamic magnetic resonance (MR) images in patients with chronic hepatitis and to correlate these findings with histopathology. Patients were entered into the study based on the presence of chronic hepatitis, imaging evaluation with MR imaging (MRI), including early and late postgadolinium images, and histopathologic correlation. Early and late dynamic postgadolinium MR images of 29 consecutive patients with a pathologically proven diagnosis of chronic hepatitis were retrospectively evaluated for the presence of three types of enhancement, i.e., homogeneous, linear, and patchy. Correlation was made between the enhancement patterns on MR images and blinded retrospective interpretation of the histopathologic specimens, which were obtained within 3 months of the MR examination. Of the 29 patients, 16 (55.2%) patients showed patchy enhancement on the early gadolinium-enhanced MR images. In 11 (68.8%) of these 16 patients, histopathology demonstrated numerous macrophages, variable hepatocyte necrosis, and increased steatosis. The remaining 13 (44.8%) patients showed homogeneous enhancement on the early gadolinium-enhanced MR images. In 11 (84.6%) of these 13 patients, histopathology demonstrated few or no macrophages, little or no hepatocellular necrosis, and little or no steatosis. The correlation between patchy enhancement and acute liver inflammation was significant (P = 0.005). On the late gadolinium-enhanced MR images, 20 (69.0%) of 29 patients showed prominent linear enhancement. In 19 (95.0%) of these 20 patients, histopathology revealed hepatic fibrosis. We concluded that in patients with chronic hepatitis, the presence of early patchy enhancement indicates either concurrent or recent hepatocellular damage, whereas the presence of late linear enhancement indicates the presence of fibrosis, with a high degree of correlation with histopathologic findings.     

Biliary dilatation: differentiation of benign from malignant causes--value of adding conventional MR imaging to MR cholangiopancreatography

PURPOSE: To determine the value of conventional T1 - and T2-weighted images and gadolinium-enhanced dynamic magnetic resonance (MR) images as a supplement to MR cholangiopancreatographic (MRCP) images in differentiation of benign from malignant causes of biliary dilatation. MATERIALS AND METHODS: MR studies in 62 patients with biliary dilatation with proved causes included conventional T1- and less heavily T2-weighted images, as well as gadolinium-enhanced dynamic images and heavily T2-weighted MRCP images. Two radiologists reviewed MRCP images alone, MRCP images with nonenhanced T1 - and T2-weighted MR images, and MRCP images with nonenhanced and gadolinium-enhanced dynamic images. RESULTS: For differentiation of benign from malignant causes of biliary dilatation, the area under the receiver operating characteristic curve (A(z)) was significantly (P < .05) larger for MRCP images interpreted with T1 - and T2-weighted images (0.9547 for reader 1, 0.8404 for reader 2) than for MRCP images alone (0.8144 for reader 1, 0.8122 for reader 2). The addition of gadolinium-enhanced dynamic MR images to MRCP images with nonenhanced T1- and T2-weighted images did not significantly increase accuracy (A(z) = 0.9554 for reader 1 and 0.8650 for reader 2), but the level of confidence was increased in 17%-24% of cases. CONCLUSION: Use of nonenhanced T1- and less heavily T2-weighted images with MRCP images significantly improved the diagnostic accuracy of MR examinations of pancreaticobiliary disease.     

MR imaging appearance of fetal cerebral ventricular morphology

PURPOSE: To compare T2-weighted breath-hold single-shot fast spin-echo (SE) and gadolinium-enhanced spoiled gradient-echo (GRE) MR imaging with contrast material administered orally and rectally for evaluating patients with Crohn disease. MATERIALS AND METHODS: Twenty-eight patients with Crohn disease received 2% barium sulfate and water enema. The abdomen and pelvis were imaged with transverse and coronal single-shot fast SE and gadolinium-enhanced spoiled GRE MR imaging. Two radiologists reviewed the two types of images for bowel disease. The extent, severity, and conspicuity of the disease were determined. Proof of bowel disease at MR imaging was compared with that at endoscopy, barium study, and surgery. Statistical analysis was performed with the McNemar test. RESULTS: Twenty-five of 28 patients had proven abnormal bowel segments. The per-patient sensitivity of gadolinium-enhanced spoiled GRE MR imaging for the two radiologists was 100% and 96% versus 60% and 60% (P <.05) with single-shot fast SE MR imaging. Gadolinium-enhanced spoiled GRE MR images depicted more segments (54 and 52 of 61 segments; sensitivity, 89% and 85%, respectively) of the diseased bowel than did single-shot fast SE MR images (31 and 32 of 61 segments; sensitivity, 51% and 52%, respectively; P <.001). Severity of Crohn disease was correctly depicted at gadolinium-enhanced spoiled GRE imaging in 93% of patients versus in 43% of patients at single-shot fast SE imaging. CONCLUSION: In patients with Crohn disease, gadolinium-enhanced fat-suppressed spoiled GRE MR imaging better depicted the extent and severity of intestinal disease compared with single-shot fast SE imaging.     

Can a multiphasic contrast-enhanced three-dimensional fast spoiled gradient-recalled echo sequence be sufficient for liver MR imaging?

OBJECTIVE: The purpose of this study was to determine the accuracy of a multiphasic gadolinium-enhanced three-dimensional (3D) fast spoiled gradient-recalled echo sequence alone in the detection and characterization of focal liver lesions compared with a comprehensive liver evaluation using multiphasic gadolinium-enhanced 3D fast spoiled gradient-recalled echo, T1-weighted, and fat-suppressed fast spin-echo T2-weighted sequences. MATERIALS AND METHODS:A retrospective review of abdominal MR imaging examinations in 61 patients was performed. All MR examinations included unenhanced spin-echo T1-weighted, unenhanced fat-suppressed fast spin-echo T2-weighted, and multiphasic gadolinium-enhanced 3D fast spoiled gradient-recalled echo sequences obtained during successive breath-holds. The liver was evaluated for focal lesions first with the 3D spoiled gradient-recalled echo sequences and then, during a separate sitting, with the T1- and T2-weighted sequences. The usefulness of each sequence in the detection and characterization of lesions was recorded. The gold standard for lesion detection and characterization was all three imaging sequences reviewed together. RESULTS:A total of 114 focal liver lesions were identified, 54 of which were simple cysts. The 3D spoiled gradient-recalled echo sequence alone detected 92 (81%) of the 114 lesions, and the T1- and T2-weighted sequences detected 95 (83%) of the 114 lesions. Of the 60 lesions that were not simple cysts, the 3D spoiled gradient-recalled echo sequence alone detected 58 (97%), and T1- and T2-weighted sequences detected 51 (85%). In 24% of the patients with lesions, the T1- and T2-weighted sequences were found to be helpful for the characterization of lesions. CONCLUSION:A multiphasic contrast-enhanced 3D fast spoiled gradient-recalled echo sequence alone detects most of the clinically relevant focal liver lesions. Additional liver examination using both unenhanced T1- and T2-weighted sequences is helpful for lesion characterization but increases the detection rate only minimally.