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.     

Detection of hepatocellular carcinoma: comparison of ferumoxides-enhanced and gadolinium-enhanced dynamic three-dimensional volume interpolated breath-hold MR imaging

The purpose was to compare the diagnostic accuracy of ferumoxides-enhanced MR imaging and gadolinium-enhanced dynamic MR imaging using three-dimensional (3D) volume interpolated breath-hold examination (VIBE) for the detection of hepatocellular carcinoma (HCC). Forty-nine patients with 61 HCCs, who underwent ferumoxides-enhanced and gadolinium-enhanced dynamic MR imaging, were included prospectively in this study. Ferumoxides-enhanced MR imaging was performed 24 h after completion of the dynamic study using 3D-VIBE. Three radiologists independently interpreted the images. The diagnostic accuracy was evaluated using the receiver-operating characteristic method, and the sensitivity of each imaging technique was compared using McNemars test. The mean diagnostic accuracy of dynamic MR imaging (Az=0.95) was higher than that of ferumoxides-enhanced MR imaging (Az=0.90), but failed to reach a statistical significance (P=0.057). The mean sensitivity of dynamic MR imaging (90.7%) was significantly superior to that of ferumoxides-enhanced MR imaging (80.9%, P=0.03). Furthermore, for lesions smaller than 15 mm, the mean sensitivity of dynamic MR imaging was significantly higher than that of ferumoxides-enhanced MR imaging (85.2% vs. 69.2%, P<0.05). Dynamic MR imaging showed a trend toward better diagnostic accuracy for than ferumoxides-enhanced MR imaging for the detection of HCCs.     

Conspicuity of hepatocellular nodular lesions in cirrhotic livers at ferumoxides-enhanced MR imaging: importance of Kupffer cell number

PURPOSE: To correlate the conspicuity of hepatocellular carcinomas and dysplastic nodules on ferumoxides-enhanced magnetic resonance (MR) images with the number of Kupffer cells in the hepatic lesions, as compared with that in background liver in histopathologic findings. MATERIALS AND METHODS: Sixty-nine histopathologically proved moderately or poorly differentiated hepatocellular carcinomas, 10 well-differentiated hepatocellular carcinomas, and 19 dysplastic nodules were retrospectively studied in 68 patients with cirrhosis who underwent ferumoxides-enhanced MR imaging. The contrast-to-noise ratio between the nodules and surrounding parenchyma was calculated at T2-weighted fast spin-echo imaging, and the difference in the number of Kupffer cells between the nodules and surrounding hepatic tissue was calculated histopathologically. The results of MR imaging and histopathologic examination were correlated. RESULTS: All 69 moderately or poorly differentiated hepatocellular carcinomas had high contrast-to-noise ratios at MR imaging and large differences in the number of Kupffer cells. Six of the 10 well-differentiated hepatocellular carcinomas had contrast-to-noise ratios of zero or nearly zero, and five of these had little difference in the number of Kupffer cells. All 19 dysplastic nodules had contrast-to-noise ratios of zero or nearly zero, and there were virtually no differences in the number of Kupffer cells. CONCLUSION: Hepatocellular nodule conspicuity at ferumoxides-enhanced MR imaging depends on differences in the number of Kupffer cells within a nodule and the surrounding cirrhotic liver; moderately or poorly differentiated hepatocellular carcinomas can be distinguished from well-differentiated hepatocellular carcinomas and dysplastic nodules.     

Preoperative detection of hepatocellular carcinoma: ferumoxides-enhanced mr imaging versus combined helical CT during arterial portography and CT hepatic arteriography

OBJECTIVE: The purpose of this study was to compare ferumoxides-enhanced MR imaging with combined helical CT during arterial portography and CT hepatic arteriography for preoperative detection of hepatocellular carcinomas. SUBJECTS AND METHODS: Twenty patients with 30 hepatocellular carcinomas underwent ferumoxides-enhanced MR imaging and combined helical CT during arterial portography and CT hepatic arteriography. The diagnosis was established by pathologic examination after surgical resection in 18 patients and by biopsy in two. The MR protocol included fast spin-echo with two echo times, T2(*)-weighted fast multiplanar gradient-recalled acquisition in the steady state, proton density-weighted fast multiplanar spoiled gradient-recalled echo, and T1-weighted fast multiplanar spoiled gradient-recalled echo images. The MR images of all sequences and the paired CT during arterial portography and CT hepatic arteriography images were independently evaluated by three radiologists on a segment-by-segment basis. Diagnostic accuracy was assessed with receiver operating characteristic analysis. RESULTS: The accuracies (A(z) values) of ferumoxides-enhanced MR imaging and combined CT during arterial portography and CT hepatic arteriography for all observers were 0.964 and 0.948, respectively. The mean sensitivities of MR imaging and CT were 93% and 91%, respectively. The differences were not statistically significant. The mean specificity of MR imaging (99%) was significantly higher than that of combined CT during arterial portography and CT hepatic arteriography (94%). CONCLUSION: Ferumoxides-enhanced MR imaging can be used successfully in place of combined CT during arterial portography and CT hepatic arteriography for the preoperative evaluation of patients with hepatocellular carcinomas.     

Detection of liver metastases: comparison of gadobenate dimeglumine-enhanced and ferumoxides-enhanced MR imaging examinations

PURPOSE: To compare gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging with ferumoxides-enhanced MR imaging for detection of liver metastases. MATERIALS AND METHODS: Twenty consecutive patients known to have malignancy and suspected of having focal liver lesions at ultrasonography (US) underwent 1.0-T MR imaging with gradient-recalled-echo T1-weighted breath-hold sequences before, immediately after, and 60 minutes after Gd-BOPTA injection. Subsequently, MR imaging was performed with turbo spin-echo short inversion time inversion-recovery T2-weighted sequences before and 60 minutes after ferumoxides administration. All patients subsequently underwent intraoperative US within 15 days, and histopathologic analysis of their resected lesion-containing specimens was performed. Separate qualitative analyses were performed to assess lesion detection with each contrast agent. Quantitative analyses were performed by measuring signal-to-noise and contrast-to-noise ratios (CNRs) on pre- and postcontrast Gd-BOPTA and ferumoxides MR images. Statistical analyses were performed with Wilcoxon signed rank and Monte Carlo tests. RESULTS: Sensitivity of ferumoxides-enhanced MR imaging was superior to that of Gd-BOPTA-enhanced MR imaging for liver metastasis detection (P <.05). Ferumoxides MR images depicted 36 (97%) of 37 metastases detected at intraoperative US, whereas Gd-BOPTA MR images depicted 30 (81%) metastases during delayed phase and 20 (54%) during dynamic phase. All six metastases identified only at ferumoxides-enhanced MR imaging were 5-10 mm in diameter. There was a significant increase in CNR between the lesion and liver before and after ferumoxides administration (from 3.8 to 6.8, P <.001) but not before or after Gd-BOPTA injection (from -4.8 to -5.5, P >.05). CONCLUSION: Ferumoxides-enhanced MR imaging seems to be superior to Gd-BOPTA-enhanced MR imaging for liver metastasis detection. Copyright RSNA, 2002     

Preoperative depiction of hepatocellular carcinoma: ferumoxides-enhanced MR imaging versus triple-phase helical CT

PURPOSE: To compare ferumoxides-enhanced magnetic resonance (MR) imaging with triple-phase helical computed tomography (CT) for the preoperative depiction of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Seventy consecutive patients with a total of 79 HCC nodules underwent ferumoxides-enhanced MR imaging and triple-phase helical CT before surgery. The diagnosis of HCC was established by means of pathologic examination after surgical resection in all patients. MR images obtained with all sequences and triple-phase helical CT images were reviewed independently by three radiologists on a segment-by-segment basis. Accuracy for diagnosis of HCC was assessed by applying receiver operating characteristic (ROC) analysis to observations of 78 hepatic segments with at least one HCC nodule and 70 segments without HCC. RESULTS: The diagnostic accuracy of findings at ferumoxides-enhanced MR imaging (with mean area-under-the-ROC-curve [A(z)] values for the three observers of 0.986, 0.979, and 0.980) was significantly higher (P <.001) than that of findings at triple-phase helical CT (with mean A(z) values for the three observers of 0.945, 0.948, and 0.964). The mean sensitivity of MR imaging (95%, 222 of 234 segments) was also significantly higher than that of triple-phase helical CT (88%, 205 of 234 segments) (P =.001, McNemar test). The mean specificity was 97% (261 of 270 segments) for MR imaging and 98% (264 of 270 segments) for CT, but this difference was not significant (P =.754, McNemar test). CONCLUSION: Ferumoxides-enhanced MR imaging is superior to triple-phase helical CT for the preoperative depiction of HCC.     

Detection of malignant hepatic lesions before orthotopic liver transplantation: accuracy of ferumoxides-enhanced MR imaging

OBJECTIVE: The purpose of this study was to evaluate the diagnostic accuracy of ferumoxides-enhanced MR imaging for screening malignant hepatic lesions before orthotopic liver transplantation. MATERIALS AND METHODS: The study comprised 48 patients who underwent MR imaging within 6 months before transplantation. Imaging techniques included unenhanced and ferumoxides-enhanced T1-weighted gradient-echo and T2-weighted fast spin-echo sequences and ferumoxides-enhanced T2(*)-weighted gradient-echo sequences. Qualitative and quantitative analyses were performed; the gold standard was the histopathologic reports of explanted livers. RESULTS: Twenty patients had malignant hepatic lesions, and 24 hepatocellular carcinomas were histopathologically proven. The mean area under the receiver operating characteristic curve and the mean sensitivity were significantly greater for the image sets with ferumoxides-enhanced gradient-echo sequences than for those without these sequences. The mean sensitivity and specificity of all sequences were 85% and 74% on a per-patient basis, respectively. The mean contrast-to-noise ratio was significantly greater for the ferumoxides-enhanced T2(*)-weighted gradient-echo sequences than for any other sequences and for the ferumoxides-enhanced T1-weighted gradient-echo sequences than for unenhanced sequences and the ferumoxides-enhanced T2-weighted fast spin-echo sequences. CONCLUSION: Ferumoxides-enhanced gradient-echo sequences improved the diagnostic accuracy and the sensitivity for detecting malignant hepatic lesions in patients with end-stage cirrhosis of the liver. However, the specificity was not improved even after the administration of ferumoxides because of the false-positive lesions that were mainly the result of fibrotic changes.     

Hepatic MR imaging using ferumoxides: prospective evaluation with surgical and intraoperative sonographic confirmation in 25 cases

OBJECTIVE: The purpose of our study was to evaluate the sensitivity and accuracy of ferumoxides-enhanced MR imaging in comparison with surgery and intraoperative sonography. SUBJECTS AND METHODS: We prospectively evaluated 25 consecutive studies in 24 patients who underwent ferumoxides-enhanced hepatic MR imaging before surgery and intraoperative sonography. Both 1.5-T scanners (13 cases) and 0.2-T scanners (12 cases) were used. Turbo spin-echo T2-weighted sequences were performed before and after the administration of ferumoxides and the images were compared. Lesions were classified as solid or nonsolid and tabulated on standard liver maps. The liver maps from MR imaging were compared with those from surgery and intraoperative sonography. For lesions greater than 1 cm, the regions of interest were measured and contrast-to-noise ratio was calculated. RESULTS: Of 93 solid lesions found at surgery, 69 were seen on unenhanced MR imaging (sensitivity, 74.2%) and 87 were seen on ferumoxides-enhanced MR imaging (sensitivity, 93.5%) (p < 0.05). Of the seven benign lesions (five cysts, two hemangiomas) found at surgery, all were correctly identified as benign on MR imaging. Two lesions identified as solid before surgery were not found at surgery. Mean lesion contrast-to-noise ratio for the unenhanced scans was 22.9 and 34.5 (p < 0.001) for the ferumoxides-enhanced scans. Subanalysis of 1.5- and 0.2-T MR imaging revealed similar results with significant (p < 0.05) increases in sensitivity for both. The average size of the lesions missed before surgery was 0.7 cm. CONCLUSION: Turbo spin-echo T2-weighted ferumoxides-enhanced MR imaging at either 1.5 or 0.2 T has value in preoperative liver assessment.     

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.     

Comparison of mangafodipir trisodium- and ferucarbotran-enhanced MRI for detection and characterization of hepatic metastases in colorectal cancer patients

OBJECTIVE: The purpose of our study was to evaluate the validity of mangafodipir trisodium-enhanced versus ferucarbotran-enhanced MRI in the detection and characterization of hepatic lesions in colorectal cancer patients. MATERIALS AND METHODS: Forty-one patients who were known to have or suspected of having hepatic metastasis from colorectal carcinoma underwent mangafodipir trisodium- or ferucarbotran-enhanced MRI in block randomization methods. Two radiologists independently reviewed the MR images to determine the number of hepatic lesions and to characterize the lesions as malignant or benign. Each lesion was assessed according to its size (small, 2 cm in diameter) on both mangafodipir trisodium- or ferucarbotran-enhanced MRI. The data were correlated with the reference diagnosis: histopathology and intraoperative sonography (n = 16); intraoperative sonography (n = 4); and imaging and clinical diagnosis with follow-up (> 3 months; n = 21). The detection rates and diagnostic accuracies of hepatic lesions on both sets of MR images were assessed using Fisher's exact test. RESULTS: Eighty-two hepatic lesions (53 metastatic and 29 benign) were identified in 41 patients. No significant differences were seen between mangafodipir trisodium- and ferucarbotran-enhanced MRI for detecting all hepatic lesions (p = 0.183), small hepatic lesions (p = 0.299), all metastases (p = 0.695), and small metastases (p = 0.689). The diagnostic accuracies of mangafodipir trisodium- and ferucarbotran-enhanced MRI showed no significant differences in all hepatic lesions (p = 0.624) and small hepatic lesions (p = 0.641). CONCLUSION: Mangafodipir trisodium- and ferucarbotran-enhanced MRI are similar in hepatic lesion detection and characterization in colorectal cancer patients.     

Nodule-in-nodule appearance of hepatocellular carcinomas: comparison of gadolinium-enhanced and ferumoxides-enhanced magnetic resonance imaging

PURPOSE: To perform comparison of gadolinium-enhanced and ferumoxides-enhanced magnetic resonance imaging (MRI) in the detection of nodule-in-nodule appearance of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: During a recent 45-month period, we had eight patients (five men and three women; age range, 63-84 years; mean, 71 years) with HCCs with nodule-in-nodule appearance who underwent gadolinium-enhanced MRI, ferumoxides-enhanced MRI, and computed tomography during arterial portography (CTAP) and computed tomography during hepatic arteriography (CTHA), combined and separately, within an interval of two weeks. Two blinded radiologists in consensus retrospectively evaluated three sets of sequences: unenhanced T1- and T2-weighted MR, gadolinium-enhanced MR, and ferumoxides-enhanced MR images in random order of patients and imaging sequences. The depiction degree of nodule-in-nodule appearance of HCC was evaluated in a semiquantitative fashion. The sensitivities of unenhanced T1- and T2-weighted, gadolinium-enhanced, and ferumoxides-enhanced MR images were compared with McNemar's test. RESULTS: The eight HCCs with nodule-in-nodule appearance ranged in size from 16-26 mm (mean, 20.0 +/- 4.0 mm), and there existed nine internal HCC foci ranging in size from 5-14 mm (mean, 7.9 +/- 3.5 mm). On gadolinium-enhanced MR images, the nodule-in-nodule appearance of HCC was typically seen as hypervascular foci in an iso- or hypovascular area: the depiction degree of nodule-in-nodule appearance was distinct in two lesions, equivocal in three, and absent in three. On ferumoxides-enhanced MR images, it was typically seen as hyperintense foci in a hypointense area: the depiction degree was distinct in four, moderate in one, and absent in three. The sensitivities for detection of nodule-in-nodule appearance were 25%, 25%, and 63% on T1- and T2-weighted, gadolinium-enhanced, and ferumoxides-enhanced MR images, respectively, but there was no significant difference in sensitivity. CONCLUSION: Nodule-in-nodule appearance of HCCs can be seen on ferumoxides-enhanced MR images, in some cases more clearly than on gadolinium-enhanced MR images, particularly when the background nodule shows hyperintensity on precontrast T1-weighted images. Ferumoxides-enhanced MRI may be considered when development of malignant foci is suspected during routine examinations.     

Diagnosing biliary complications of orthotopic liver transplantation with mangafodipir trisodium-enhanced MR cholangiography: comparison with conventional MR cholangiography

OBJECTIVE: This study was designed to determine whether the addition of mangafodipir trisodium-enhanced MRI could improve the image quality, visualization of ductal structures, and diagnostic confidence provided by conventional T2-based MR cholangiography (MRC) in patients with suspected biliary complications after orthotopic liver transplantation. SUBJECTS AND METHODS. Our study group consisted of 25 consecutive patients who were referred for MR evaluation of clinically suspected biliary complications after orthotopic liver transplantation. Conventional MRC in the axial and coronal planes was performed in each patient, followed by fat-suppressed volumetric gradient-echo imaging in the same planes both before and after the IV administration of mangafodipir trisodium. Imaging was performed in all patients until the contrast agent was seen in the bowel. Images were then graded for quality, visualization of bile ducts and anastomoses, presence of significant stricture or leak, and level of diagnostic confidence. RESULTS: Mangafodipir trisodium-enhanced MRC tended to outperform conventional MRC in overall image quality and extrahepatic duct visualization; it was also more effective in delineating biliary anastomoses, and the difference was statistically significant (p < 0.001). All 25 enhanced examinations were considered diagnostic. Diagnostic confidence was scored as poor or lacking in 14 of the conventional MRC examinations for biliary stenosis and in 12 examinations for biliary leak. CONCLUSION: Enhancement with mangafodipir trisodium improves the performance of MRC for the detection and exclusion of biliary abnormalities after orthotopic liver transplantation. Future investigations should compare the performance of mangafodipir trisodium-enhanced MRC with the performance of more invasive techniques.     

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.     

Characterization of focal hepatic lesions with ferumoxides-enhanced T2-weighted MR imaging

OBJECTIVE: The purpose of this study was to evaluate whether ferumoxides-enhanced MR imaging of focal hepatic lesions provides distinctive signal intensity and lesion-to-liver contrast changes for benign and malignant lesions, helping to further characterize and differentiate these lesions. MATERIALS AND METHODS: Data analysis was performed on 70 patients, with previously identified focal hepatic lesions, who underwent MR imaging of the liver before and after IV administration of ferumoxides (10 micromol Fe/kg). Lesions analyzed with pathologically proven diagnoses included metastases (n = 40), hepatocellular carcinoma (n = 11), cholangiocarcinoma (n = 6), hemangioma (n = 4), focal nodular hyperplasia (n = 6), and hepatocellular adenoma (n = 3). Response variables measured and statistically compared included the percentage of signal-intensity change and lesion-to-liver contrast. RESULTS: Focal nodular hyperplasia showed significant signal intensity loss on ferumoxides-enhanced T2-weighted images (mean, -43%+/-6.7%, p < 0.01). All other lesion groups showed no statistically significant change in signal intensity on ferumoxides-enhanced T2-weighted images, although signal intensity loss was seen in some individual hepatocellular adenomas (mean, -6.6%+/-24.0%) and hepatocellular carcinomas (mean, -3.3%+/-10.3%). All lesions, with the exception of hepatocellular carcinoma, had a marked increase in lesion-to-liver contrast on ferumoxides-enhanced T2-weighted images, which was statistically significant for metastases and hemangioma (p < 0.02). CONCLUSION: Focal nodular hyperplasia shows significant decrease in signal intensity on ferumoxides-enhanced T2-weighted images, which may aid in the differentiation of focal nodular hyperplasia from other focal hepatic lesions. Other lesions, namely, hepatocellular adenoma and carcinoma, can have reticuloendothelial uptake, but usually to a lesser degree than that of focal nodular hyperplasia.     

Characterization of hepatocellular tumors: value of mangafodipir-enhanced magnetic resonance imaging

PURPOSE: To assess the value of mangafodipir trisodium-enhanced MR imaging for characterization of hepatocellular lesions. MATERIALS AND METHODS: Magnetic resonance images of 41 patients with 48 histopathologically proven hepatocellular lesions (20 cases of focal nodular hyperplasia [FNH], 4 adenomas, 15 hepatocellular carcinomas [HCCs], 7 regenerative nodules, and 2 others) were retrospectively studied. Magnetic resonance imaging was performed on a 1.5-T unit (Vision, Siemens, Erlangen, Germany; ACS-NT, Philips, Best, The Netherlands) using T2-weighted, fat-saturation, turbo spin echo imaging and T1-weighted gradient echo imaging before and 20 minutes after infusion of 5 micromol/kg mangafodipir (Amersham Health, Oslo, Norway). Qualitative analysis by 4 blinded independent readers included assessment of unenhanced images and, in a second step, assessment of unenhanced and contrast-enhanced images together. Lesions were classified as benign or malignant using a 5-point scale, and readers made a specific diagnosis. RESULTS: For characterization of hepatocellular lesions, mangafodipir-enhanced imaging was significantly superior to unenhanced imaging (P < 0.05). On receiver operating characteristic analysis, the area under the curve was 0.768 (95% confidence interval: 0.633-0.903) for unenhanced images and 0.866 (95% confidence interval: 0.767-0.966) for evaluation of unenhanced and contrast-enhanced images together (P < 0.05). Analysis of enhancement patterns aided in characterization and classification of tumors. CONCLUSION: Administration of mangafodipir improves the differentiation between adenoma or HCC and "nonsurgical" lesions (FNH or regenerative nodules). The accuracy for arriving at a specific diagnosis is higher when unenhanced and mangafodipir-enhanced images are considered together than for unenhanced MR images alone.     

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.     

Routine MR imaging protocol with breath-hold fast scans: diagnostic efficacy for focal liver lesions

PURPOSE: To qualitatively and quantitatively evaluate the diagnostic efficacy of the breath-hold magnetic resonance (MR) imaging sequences in widespread clinical use for detection and characterization of focal hepatic lesions. MATERIALS AND METHODS: Fifty patients with 143 lesions [57 hepatocellular carcinomas (HCC), 10 borderline lesions, 18 metastatic tumors, 21 hemangiomas, and 37 cysts] underwent single-shot fast spin echo (SSFSE), fast spin echo (FSE), and gadolinium-enhanced dynamic fast spoiled gradient-recalled acquisition in steady state (FSPGR) breath-hold MR imaging of the liver. Alternative free receiver operating characteristic (AFROC) analysis was performed to independently and prospectively assess each sequence. RESULTS: For solid lesions, dynamic FSPGR allowed the most sensitive lesion detection and produced the highest lesion conspicuity and lesion-liver contrast-to-noise ratio (CNR). For non-solid benign lesions, SSFSE and FSE produced better results than dynamic FSPGR. SSFSE allowed the most sensitive detection and produced the best lesion conspicuity and lesion-liver CNR. CONCLUSION: SSFSE and dynamic FSPGR comprise the optimal imaging protocol for breath-hold MR assessment of focal hepatic lesions. This combination of sequences allows acquisition of critical diagnostic information about both inherent T2 and T1 lesion contrast and lesion vascularity.     

Characterization of focal hepatic lesions with ferumoxides-enhanced MR imaging: utility of T1-weighted spoiled gradient recalled echo images using different echo times

PURPOSE: To evaluate the different signal characteristics of focal hepatic lesions on ferumoxides-enhanced MR imaging, including T1-weighted spoiled gradient recalled echo (GRE) images using different echo times (TE) and T2- and T2*-weighted images. MATERIALS AND METHODS: Ferumoxides-enhanced MR imaging was performed using a 1.5-T system in 46 patients who were referred for evaluation of known or suspected hepatic malignancies. One hundred and seven lesions (42 hepatocellular carcinomas [HCC], 40 metastases, 13 cysts, eight hemangiomas, three focal nodular hyperplasias [FNHs], and one cholangiocarcinoma) were evaluated. Postcontrast MR imaging included 1) T2-weighted FSE; 2) T2*-weighted GRE; 3) T1-weighted spoiled GRE using moderate (TE = 4.2-4.4 msec) TE; and 4) minimum (TE = 1.8-2.1 msec) TE. Signal intensities of the focal lesions were rated by two radiologists in conference as follows: hypointense, isointense or invisible, hyperintense, and markedly hyperintense. Lesion-to-liver contrast-to-noise ratio (C/N) was measured by one radiologist for a quantitative assessment. RESULTS: On ferumoxides-enhanced FSE images, 92% of cysts were "markedly hyperintense" and most of the other lesions were "hyperintense", and the mean C/N of cysts was significantly higher than that of other focal lesions. T2*-weighted GRE images showed most lesions with similar hyperintensities and the mean C/N was not significantly different between any two types of lesion. T1-weighted GRE images using moderate TE showed all FNHsand hemangiomas, 29 (69%) HCCs and eight (20%) metastases as "hyperintense". On T1-weighted GRE images using minimum TE, however, all HCCs and metastasis except one were iso- or hypointense, while all of the FNHs and hemangiomas were hyperintense. Ring enhancement was highly suggestive of malignant lesions, and was more commonly seen on the minimum TE images than on the moderate TE images. CONCLUSION: Addition of T1-weighted GRE images using minimum and moderate TE is helpful for characterizing focal lesions in ferumoxides-enhanced MR imaging.     

Sequence optimization in mangafodipir trisodium-enhanced liver and pancreas MRI

To find an optimal magnetic resonance (MR) sequence for mangafodipir trisodium-enhanced liver and pancreas imaging, six healthy volunteers were studied using a 1.5 T MR system with different T1-weighted abdominal imaging sequences. These were turbo field (gradient)-echo (TFE), fast field (gradient)-echo (FFE), and spin-echo sequences before and after mangafodipir trisodium administration. Various parameter combinations were investigated within each sequence type, and then the best combination was found and compared with those of the other sequences. Signal intensity (SI) measurements were made in regions of interest in the liver, pancreas, and a reference marker with a known T1 value. Contrast index (CI, SItissue/SImarker) and contrast-to-noise ratio (CNR, [SItissue/SImarker]/SDbackground) were calculated, and percentage CI increase and CNR in the postcontrast images were used for the best sequence evaluation. Regarding CI, the TFE sequence with a TR/TE/flip angle of 15 msec/4.6 msec/20 degrees and inversion time of 300 msec had the largest pre- to postcontrast percentage increase. The FFE sequence with a TR/TE/flip angle of 140 msec/4.6 msec/90 degrees had the highest postcontrast CNR and is considered to be the optimal sequence for mangafodipir trisodium-enhanced MR imaging of the liver and pancreas.     

Diagnosis and staging of pancreatic cancer: comparison of mangafodipir trisodium-enhanced MR imaging and contrast-enhanced helical hydro-CT

OBJECTIVE: The purpose of this study was to compare mangafodipir trisodium-enhanced MR imaging performed with a phased array coil and contrast-enhanced single-detector helical CT for accuracy in the detection and local staging of pancreatic adenocarcinoma and in the differentiation between cancer and focal pancreatitis. SUBJECTS AND METHODS: Forty-two patients with suspected pancreatic masses underwent contrast-enhanced helical CT and mangafodipir trisodium-enhanced MR imaging at 1.5 T. The images were assessed for the presence or absence of tumors; characterization of masses; and presence of vascular invasion, lymph node metastases, or liver metastases. Imaging findings were correlated with findings at laparotomy, laparoscopy, biopsy, or follow-up. RESULTS: Focal masses were present in 36 patients (cancer, n = 26; focal pancreatitis, n = 7; other, n = 3). The sensitivity for lesion detection of MR imaging was 100% and of CT, 94%. Two small malignant lesions were missed on CT. For the diagnosis of tumor nonresectability, the sensitivity of MR imaging and CT was 90% and 80%, respectively. Liver metastases were missed on MR imaging in one of the eight patients and on CT in four. For differentiation between adenocarcinoma and nonadenocarcinoma, the sensitivity of MR imaging was 100% (positive predictive value, 90%; negative predictive value, 100%), and the sensitivity of CT was 92% (positive predictive value, 80%; negative predictive value, 67%). Receiver operating characteristic analysis revealed that the mean area under the curve for MR imaging was 0.920 and for CT, 0.832 (not significant). CONCLUSION: Mangafodipir trisodium-enhanced MR imaging is as accurate as contrast-enhanced helical CT for the detection and staging of pancreatic cancer but offers improved detection of small pancreatic metastases and of liver metastases compared with CT.