Michele Di Martino

Intraindividual Comparison of Gadoxetate Disodium–enhanced MR Imaging and 64-Section Multidetector CT in the Detection of Hepatocellular Carcinoma in Patients with Cirrhosis

PURPOSE To prospectively compare gadoxetate disodium-enhanced magnetic resonance (MR) imaging with multiphasic 64-section multidetector computed tomography (CT) in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis. MATERIALS AND METHODS Institutional review board approval and informed patient consent were obtained for this prospective study. Fifty-eight patients (39 men, 19 women; mean age, 63 years; age range, 35-84 years) underwent gadoxetate disodium-enhanced MR imaging and multiphasic 64-section multidetector CT. The imaging examinations were performed within 30 days of each other. The two sets of images were qualitatively analyzed in random order by three independent readers in a blinded and retrospective fashion. Using strict diagnostic criteria for HCC, readers classified all detected lesions with use of a four-point confidence scale. The reference standard was a combination of pathologic proof, conclusive imaging findings, and substantial tumor growth at follow-up CT or MR imaging (range of follow-up, 90-370 days). The diagnostic accuracy, sensitivity, and positive predictive value were compared between the two image sets. Interreader variability was assessed. The accuracy of each imaging method was determined by using an adjusted modified chi(2) test. RESULTS Eighty-seven HCCs (mean size +/- standard deviation, 1.8 cm +/- 1.5; range, 0.3-7.0 cm) were confirmed in 42 of the 58 patients. Regardless of lesion size, the average diagnostic accuracy and sensitivity for all readers were significantly greater with gadoxetate disodium-enhanced MR imaging (average diagnostic accuracy: 0.88, 95% confidence interval [CI]: 0.80, 0.97; average sensitivity: 0.85, 95% CI: 0.74, 0.96) than with multidetector CT (average diagnostic accuracy: 0.74, 95% CI: 0.65, 0.82; average sensitivity: 0.69, 95% CI: 0.59, 0.79) (P < .001 for each). No significant difference in positive predictive value was observed between the two image sets for each reader. Interreader agreement was good to excellent. CONCLUSION Compared with multiphasic 64-section multidetector CT, gadoxetate disodium-enhanced MR imaging yields significantly higher diagnostic accuracy and sensitivity in the detection of HCC in patients with cirrhosis.

Hepatocellular Carcinoma in Patients with Cirrhosis: Qualitative Comparison of Gadobenate Dimeglumine–enhanced MR Imaging and Multiphasic 64-Section CT

PURPOSE To prospectively investigate whether combined interpretation of dynamic and hepatobiliary phase magnetic resonance (MR) images can improve the accuracy of gadobenate dimeglumine-enhanced MR imaging in the detection of hepatocellular carcinoma (HCC) compared with either dynamic MR or multiphasic multidetector computed tomographic (CT) images alone. MATERIALS AND METHODS Institutional review board approval and informed patient consent were obtained. Fifty-two patients (39 men, 13 women; mean age, 68 years; range, 38-81 years) suspected of having HCC underwent gadobenate dimeglumine-enhanced MR imaging and multiphasic 64-section multidetector CT. Images were qualitatively analyzed independently by three observers in three separate reading sessions. The alternating free-response receiver operating characteristic (AFROC) method was used to analyze the results. Differences in sensitivity and positive predictive values were calculated at a statistical significance of P < .05. RESULTS A total of 67 HCCs were detected in 36 patients. The mean area under the AFROC curve (A(z)) was significantly higher for either the combined interpretation of dynamic and hepatobiliary phase MR images (A(z) = 0.95) or dynamic MR images alone (0.91) than for CT images (0.77) (P = .01 for both comparisons). The mean sensitivity of combined interpretation of MR images (0.72) was significantly higher than those of dynamic MR images alone (0.63) and multidetector CT images (0.61) (P = .008 and .001, respectively). The mean positive predictive value was not significantly different among the three imaging sets. CONCLUSION The combined interpretation of dynamic and hepatobiliary phase MR images improves diagnostic accuracy of gadobenate dimeglumine-enhanced MR imaging for the detection of HCC compared with either dynamic MR or multiphasic multidetector CT images alone.

T1-weighted dual-echo MRI for fat quantification in pediatric nonalcoholic fatty liver disease

AIM To determine in obese children with nonalcoholic fatty liver disease (NAFLD) the accuracy of magnetic resonance imaging (MRI) in assessing liver fat concentration. METHODS A case-control study was performed. Cases were 25 obese children with biopsy-proven NAFLD. Controls were 25 obese children matched for age and gender, without NAFLD at ultrasonography and with normal levels of aminotransferases and insulin. Hepatic fat fraction (HFF) by MRI was obtained using a modification of the Dixon method. RESULTS HFF ranged from 2% to 44% [mean, 19.0% (95% CI, 15.1-27.4)] in children with NAFLD, while in the controls this value ranged from 0.08% to 4.69% [2.0% (1.3-2.5), P < 0.0001]. HFF was highly correlated with histological steatosis (r = 0.883, P < 0.0001) in the NAFLD children. According to the histological grade of steatosis, the mean HFF was 8.7% (95% CI, 6.0-11.6) for mild, 21.6% (15.3-27.0) for moderate, and 39.7% (34.4-45.0) for severe fatty liver infiltration. With a cutoff of 4.85%, HFF had a sensitivity of 95.8% for the diagnosis of histological steatosis ≥ 5%. All control children had HFF lower than 4.85%; thus, the specificity was 100%. After 12 mo, children with weight loss displayed a significant decrease in HFF. CONCLUSION MRI is an accurate methodology for liver fat quantification in pediatric NAFLD.

Sarcopenia in liver cirrhosis: the role of computed tomography scan for the assessment of muscle mass compared with dual-energy X-ray absorptiometry and anthropometry.

Background Sarcopenia evaluated by computed tomography (CT) scan at the lumbar site has been identified as a risk factor for morbidity and mortality in cirrhosis. Aim The aim of this study was to compare the measurement of muscle mass through CT scan, considered the gold standard, with other reliable techniques to evaluate the rate of agreement between different available methods for the assessment of muscle mass in cirrhosis. The correlation between measurements of muscle mass and of muscle strength was also investigated. Patients and methods Adult patients eligible for liver transplantation were studied. Lumbar skeletal muscle cross-sectional area was measured by CT and muscle depletion was defined using previously published cut-offs. Mid-arm muscle circumference was calculated following anthropometric measures. The Fat-Free Mass Index and the Appendicular Skeletal Muscle Index were calculated using dual-energy X-ray absorptiometry. Muscle strength was evaluated using the Hand Grip test. Results Fifty-nine patients with cirrhosis were included. Sarcopenia was diagnosed in 76% of the patients according to CT evaluation. A significant reduction in Fat-Free Mass Index and Appendicular Skeletal Muscle Index was observed in 42–52% of the patients, whereas 52% showed a mid-arm muscle circumference less than 10th percentile. Skeletal muscle mass evaluation through CT was only weakly correlated with dual-energy X-ray absorptiometry and anthropometry evaluation. No correlation was observed between CT measurement of muscle mass and Hand Grip test. Conclusion CT scan can identify the highest percentage of sarcopenia in cirrhosis and no other techniques are actually available as a replacement. Future efforts should focus on approaches for assessing both skeletal muscle mass and function to provide a better evaluation of sarcopenia in cirrhotic patients.

Hepatocellular carcinoma presenting at contrast-enhanced multi-detector-row computed tomography or gadolinium-enhanced magnetic resonance imaging as a small (≤2 cm), indeterminate nodule: growth rate and optimal interval time for imaging follow-up.

Objective The objective of the study was to measure growth rate and to determine the optimal interval time for imaging follow-up of hepatocellular carcinomas (HCCs) presenting at multi–detector-row computed tomography (MDCT) or magnetic resonance imaging (MRI) as small, indeterminate lesions. Methods We included patients with cirrhosis with HCC initially presenting as indeterminate lesion of 2 cm or less at MDCT or MRI August 2005 to August 2009 and with available imaging follow-up. Measures of tumor growth included tumor volume doubling time (TVDT), tumor percentual diameter increase, and tumor percentual volume increase. Results We examined 48 patients (mean age, 64 years) with 69 HCCs. At index examination, mean (SD) maximum transverse diameter and volume of lesions were 1.2 (SD, 0.3) cm and 0.6 (SD, 0.7) cm3, respectively. Median TVDT was 210 days. Tumors with follow-up longer than 365 days had significant increase in tumor percentual diameter increase and tumor percentual volume increase. Conclusions Median TVDT of 210 days suggests extended follow-up of 6 months for small, indeterminate liver nodules detected at MDCT or MRI.

Detection of Hepatocellular Carcinoma in Patients with Cirrhosis: Added Value of Coronal Reformations from Isotropic Voxels with 64-MDCT

OBJECTIVE The purpose of our study was to prospectively assess the added value of isotropic coronal reformations of the liver when using 64-MDCT for the detection of hepatocellular carcinoma (HCC). SUBJECTS AND METHODS Seventy-one consecutive patients (60 men, 11 women; mean age, 65 years) suspected of having HCC underwent 64-MDCT with coronal reformations. A multiphasic CT protocol that included unenhanced, hepatic arterial, portal venous, and equilibrium phases was performed. Three independent, blinded readers interpreted the transverse scan alone, the coronal scan alone, and the combined transverse and coronal scans for the presence of HCC. Sensitivity, positive predictive value, area under the receiver operating characteristic curve (A(z)), and interpretation time were calculated for each reading session. RESULTS Seventy-six HCC nodules were confirmed in 48 patients using histopathologic analysis or follow-up with long-term CT, MRI, or both (mean follow-up time, 12 months; range, 12-15 months) as the reference standard. Mean sensitivity, positive predictive value, and A(z) value for HCC detection were, respectively, 84% (191/228 readings), 91% (191/210 readings), and 0.85 for the transverse scan alone; 83% (189/228 readings), 93% (189/203 readings), and 0.86 for the coronal scan alone; and 87% (198/228 readings), 93% (198/213 readings), and 0.87 for combined interpretation of transverse and coronal scans. No comparisons were statistically significant. Forty-eight false-positive interpretations were recorded (19 for the transverse, 14 for the coronal, and 15 for the combined interpretation sets). The reading session in which combined transverse and coronal scans were available for interpretation showed significantly superior reader confidence for HCC detection as well as longer interpretation times (p<0.05 for both comparisons). The average reading time for the combined interpretation of transverse and coronal image sets (mean, 12.1+/-0.8 minutes) was significantly longer than for the transverse image set (7.4+/-1.5 minutes) or the coronal image set (7.1+/-1.3 minutes) (p<0.01). CONCLUSION With 64-MDCT, the addition of isotropic coronal reformations to transverse images significantly improved reader confidence for the detection of HCC, with no statistically significant improvement in sensitivity, positive predictive value, or diagnostic accuracy (as determined by the A(z) value). This improvement comes at the cost of a longer interpretation time.

Comparison of magnetic resonance spectroscopy, proton density fat fraction and histological analysis in the quantification of liver steatosis in children and adolescents

AIM To establish a threshold value for liver fat content between healthy children and those with non-alcoholic fatty liver disease (NAFLD) by using magnetic resonance imaging (MRI), with liver biopsy serving as a reference standard. METHODS The study was approved by the local ethics committee, and written informed consent was obtained from all participants and their legal guardians before the study began. Twenty-seven children with NAFLD underwent liver biopsy to assess the presence of nonalcoholic steatohepatitis. The assessment of liver fat fraction was performed using MRI, with a high field magnet and 2D gradient-echo and multiple-echo T1-weighted sequence with low flip angle and single-voxel point-resolved ¹H MR-Spectroscopy (¹H-MRS), corrected for T1 and T2* decays. Receiver operating characteristic curve analysis was used to determine the best cut-off value. Lin coefficient test was used to evaluate the correlation between histology, MRS and MRI-PDFF. A Mann-Whitney U-test and multivariate analysis were performed to analyze the continuous variables. RESULTS According to MRS, the threshold value between healthy children and those with NAFLD is 6%; using MRI-PDFF, a cut-off value of 3.5% is suggested. The Lin analysis revealed a good fit between the histology and MRS as well as MRI-PDFF. CONCLUSION MRS is an accurate and precise method for detecting NAFLD in children.

Bladder carcinoma: MDCT cystography and virtual cystoscopy

AbstractBladder carcinoma is the most common tumor among the low urinary tract, accounting for 90% of cancer cases. Conventional cystoscopy represents the gold standard for diagnosis and local management of bladder carcinoma. As the prevalence of transitional cell carcinoma is four-fold greater in men than in women, the endoscopic procedure presents objective difficulties related to the length and bending of male urethra. The most important problems are represented by intense discomfort for the patient and bleeding; furthermore, the high cost, invasivity, and local complications such as infections and mechanical lesions are well-known drawbacks. Additionally, conventional cystoscopy does not provide information about extravescical extensions of the tumor. CT cystography, combined with virtual cystoscopy, is mandatory for TNM staging of the tumor and also is useful when conventional cystoscopy is inconclusive or cannot be performed. We presents the CT cystography findings with virtual endoscopy correlation and bladder carcinoma appearance.

Pancreatic fat and β-cell function in overweight/obese children with nonalcoholic fatty liver disease

AIM To analyze the associations of pancreatic fat with other fat depots and β-cell function in pediatric nonalcoholic fatty liver disease (NAFLD). METHODS We examined 158 overweight/obese children and adolescents, 80 with NAFLD [hepatic fat fraction (HFF) ≥ 5%] and 78 without fatty liver. Visceral adipose tissue (VAT), pancreatic fat fraction (PFF) and HFF were determined by magnetic resonance imaging. Estimates of insulin sensitivity were calculated using the homeostasis model assessment of insulin resistance (HOMA-IR), defined by fasting insulin and fasting glucose and whole-body insulin sensitivity index (WBISI), based on mean values of insulin and glucose obtained from oral glucose tolerance test and the corresponding fasting values. Patients were considered to have prediabetes if they had either: (1) impaired fasting glucose, defined as a fasting glucose level ≥ 100 mg/dL to < 126 mg/dL; (2) impaired glucose tolerance, defined as a 2 h glucose concentration between ≥ 140 mg/dL and < 200 mg/dL; or (3) hemoglobin A1c value of ≥ 5.7% to < 6.5%. RESULTS PFF was significantly higher in NAFLD patients compared with subjects without liver involvement. PFF was significantly associated with HFF and VAT, as well as fasting insulin, C peptide, HOMA-IR, and WBISI. The association between PFF and HFF was no longer significant after adjusting for age, gender, Tanner stage, body mass index (BMI)-SD score, and VAT. In multiple regression analysis with WBISI or HOMA-IR as the dependent variables, against the covariates age, gender, Tanner stage, BMI-SD score, VAT, PFF, and HFF, the only variable significantly associated with WBISI (standardized coefficient B, -0.398; P = 0.001) as well as HOMA-IR (0.353; P = 0.003) was HFF. Children with prediabetes had higher PFF and HFF than those without. PFF and HFF were significantly associated with prediabetes after adjustment for clinical variables. When all fat depots where included in the same model, only HFF remained significantly associated with prediabetes (OR = 3.38; 95%CI: 1.10-10.4; P = 0.034). CONCLUSION In overweight/obese children with NAFLD, pancreatic fat is increased compared with those without liver involvement. However, only liver fat is independently related to prediabetes.

Gadobenate dimeglumine-enhanced magnetic resonance imaging of primary leiomyoma of the liver

We report a case of histologically proven primary leiomyoma of the liver that was evaluated with multiphasic 64‐section computed tomography (CT) and gadobenate dimeglumine–enhanced magnetic resonance (MR) imaging. This lesion showed vivid enhancement during the arterial phase with sustained enhancement during the hepatic venous and equilibrium phases. During the liver‐specific MR imaging phase (150 minutes after contrast injection), the same lesion demonstrated lack of contrast retention, thus appearing hypointense compared with the background liver. Because of this latter finding, the patient underwent partial resection of the liver. In primary hepatic leiomyoma, the absence of contrast uptake during the liver‐specific phase of gadobenate dimeglumine–enhanced MR imaging may be inappropriately interpreted as a sign of malignancy, thus leading to unnecessary, aggressive management of such lesions. J. Magn. Reson. Imaging 2008;28:755–758.