Preliminary Comparison of Multi-scale and Multi-model Direct Inversion Algorithms for 3T MR Elastography.

PURPOSE: To elucidate whether any differences are present in the stiffness map obtained with a multiscale direct inversion algorithm (MSDI) vs that with a multimodel direct inversion algorithm (MMDI), both qualitatively and quantitatively. MATERIALS AND METHODS: The MR elastography (MRE) data of 37 consecutive patients who underwent liver MR elastography between September and October 2014 were retrospectively analyzed by using both MSDI and MMDI. Two radiologists qualitatively assessed the stiffness maps for the image quality in consensus, and the measured liver stiffness and measurable areas were quantitatively compared between MSDI and MMDI. RESULTS: MMDI provided a stiffness map of better image quality, with comparable or slightly less artifacts. Measurable areas by MMDI (43.7 ± 17.8 cm2) was larger than that by MSDI (37.5 ± 14.7 cm2) (P < 0.05). Liver stiffness measured by MMDI (4.51 ± 2.32 kPa) was slightly (7%), but significantly less than that by MSDI (4.86 ± 2.44 kPa) (P < 0.05). CONCLUSION: MMDI can provide stiffness map of better image quality, and slightly lower stiffness values as compared to MSDI at 3T MRE, which radiologists should be aware of.

Which system is better to predict prognosis of patients with hepatocellular carcinoma treated by transcatheter arterial chemoembolization as initial therapy? Comparison between CLIP and JIS in a Japanese population.

Background There has been no consensus as to which system, either the Cancer of the Liver Italian Program (CLIP) or the Japan Integrated Staging (JIS) system, is suitable to predict the prognosis of hepatocellular carcinoma (HCC) patients who underwent transcatheter arterial chemoembolization (TACE) as initial therapy. Purpose To retrospectively compare the usefulness of CLIP and JIS in predicting and stratifying the prognosis of HCC patients treated by TACE. Material and Methods Between 1995 and 2005, consecutive 728 patients with untreated HCC who underwent TACE in our institute were selected for this study. The survival rate and its prognostic factors were assessed by multivariate analysis. Patients were stratified according to the two systems, and their survival rates between the scores were compared. Results The mean follow-up period was 1689 days. The 1-year, 3-year, 5-year, and 10-year survival rates were 83.1%, 55.1%, 34.7%, and 12.8%, respectively. Both systems stratified the prognosis of patients well, but was slightly better in CLIP as compared to in JIS. As for multivariate factor analysis, less severe Child-Pugh classification ( P < 0.001), simple tumor morphology ( P < 0.001), absence of portal vein invasion ( P < 0.001), and lower alpha-fetoprotein (AFP) level ( P < 0.001) were suggested to be independent indicators for favorable survival rate. All of these independent factors were included in CLIP, whereas JIS lacked AFP level. Furthermore, the likelihood χ2-test value was higher, and the Akaike information criterion value was lower for CLIP than for JIS. Conclusion CLIP is more suitable than JIS for predicting prognosis of patients with HCC who would undergo TACE in a Japanese population.

MR elastography of the liver at 3.0 T in diagnosing liver fibrosis grades; preliminary clinical experience.

OBJECTIVES: To clarify the usefulness of 3.0-T MR elastography (MRE) in diagnosing the histological grades of liver fibrosis using preliminary clinical data. MATERIALS AND METHODS: Between November 2012 and March 2014, MRE was applied to all patients who underwent liver MR study at a 3.0-T clinical unit. Among them, those who had pathological evaluation of liver tissue within 3 months from MR examinations were retrospectively recruited, and the liver stiffness measured by MRE was correlated with histological results. Institutional review board approved this study, waiving informed consent. RESULTS: There were 70 patients who met the inclusion criteria. Liver stiffness showed significant correlation with the pathological grades of liver fibrosis (rho = 0.89, p < 0.0001, Spearman's rank correlation). Areas under the receiver operating characteristic curve were 0.93, 0.95, 0.99 and 0.95 for fibrosis score greater than or equal to F1, F2, F3 and F4, with cut-off values of 3.13, 3.85, 4.28 and 5.38 kPa, respectively. Multivariate analysis suggested that grades of necroinflammation also affected liver stiffness, but to a significantly lesser degree as compared to fibrosis. CONCLUSIONS: 3.0-T clinical MRE was suggested to be sufficiently useful in assessing the grades of liver fibrosis. KEY POINTS: MR elastography may help clinicians assess patients with chronic liver diseases. Usefulness of 3.0-T MR elastography has rarely been reported. Measured liver stiffness correlated well with the histological grades of liver fibrosis. Measured liver stiffness was also affected by necroinflammation, but to a lesser degree. 3.0-T MRE could be a non-invasive alternative to liver biopsy.

Optimization of scanning parameters for MR elastography at 3.0 T clinical unit: volunteer study.

PURPOSE: We sought to optimize scanning parameters for MR elastography at 3.0 T clinical unit. MATERIALS AND METHODS: 10 volunteers were scanned with various magnetization encoding gradient (MEG) frequencies from 60 to 120 Hz at every 10 Hz, with otherwise fixed parameters (external driver frequency/amplitude = 60 Hz/50 %, 10 mm slice thickness, etc.). Images were qualitatively assessed for the degree of image defects, and also quantitatively for the areas without cross-hatching. After determining optimal MEG frequency, external driver amplitudes of 70 % (vs 50 %) and slice thickness of 8 mm (vs 10 mm) were also tested. With the optimized parameters, scans were repeated 1 week after the initial scan, and the repeatability of the liver stiffness measurement was validated. RESULTS: 80 or 90 Hz was shown to be the best MEG frequency. There were no significant differences in the qualitative and quantitative assessment between the two amplitudes and two slice thicknesses; however, 70 % amplitude resulted in discomfort at the chest wall beneath the external acoustic driver. Thus, MEG 80 (or 90) Hz, amplitude 50 %, and thickness 10 (or 8) mm were considered optimal. Repeatability of the liver stiffness measurement was ±10 % (95 % confidence interval). CONCLUSIONS: With the optimized parameters, repeatability of ±10 % in liver stiffness measurement was obtained.

Focal fatty change in the liver that developed after cholecystectomy.

Focal fatty change of the segment IV of the liver has been attributed to local systemic venous inflow replacing the portal venous supply, which could develop or be accentuated after gastrectomy. However, focal fatty change due to aberrant pancreaticoduodenal vein that developed after cholecystectomy has never been reported. We report a 30-year-old man with such a rare lesion, which was initially misdiagnosed as a hepatocellular carcinoma, but was confirmed on computed tomography during selective gastroduodenal arteriography. The lesion disappeared 12 mo later without any intervention.

Measurement consistency of MR elastography at 3.0 T: comparison among three different region-of-interest placement methods.

PURPOSE: To test inter- and intraobserver consistency of liver stiffness measurement on MR elastography (MRE) at 3.0 T. MATERIALS AND METHODS: Two abdominal radiologists independently measured stiffness of the liver on MRE in three volunteers and seven patients with chronic liver diseases using three different region-of-interest (ROI) placement methods. Methods 1 and 2 involved placing circular and free-hand-drawn ROIs, respectively, visually referring to anatomical (three-dimensional T1-weighted) and wave images. Method 3 involved placing ROIs on the fused images of MRE and anatomical images developed on a work station, visually referring to wave images. The inter- and intraobserver consistency was assessed with regression and Bland-Altman analysis. RESULTS: Thirty-eight images were available for measurement in total. As for interobserver consistency, method 3 showed the best regression coefficient, correlation coefficient, and y intercept. The absolute values of the interobserver differences for method 3 were significantly smaller than those of method 1 or method 2 (p < 0.05, each). Intraobserver consistency of method 3 was excellent for both observers. CONCLUSION: Stiffness measurement of the liver on MRE performed with the fusion method at 3.0 T provides the highest inter- and intraobserver consistency.

Warming effect on miriplatin-lipiodol suspension for potential use as a chemotherapeutic agent for transarterial chemoembolization of hepatocellular carcinoma: In vitro study.

AIM: To elucidate whether warming may reduce the viscosity of miriplatin-lipiodol suspension (MPT/LPD) and also the injection pressure through microcatheters, for potential use as a chemotherapeutic agent of transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). METHODS: Viscosity of MPT/LPD prepared at on-label dose was measured in vitro at 25°C, 30°C, 40°C, 50°C and 60°C using capillary tube method. Reproducibility of viscosity change was also tested. Injection pressure through two different commercially available microcatheters was measured using a rheometer. Data sampling was performed at least twice for each measurement. RESULTS: Viscosity of MPT/LPD was significantly reduced as the temperature was elevated (R(2) = 0.9586, P < 0.0001, Pearson's correlation); at 40°C, it was almost half of that at room temperature (25°C). Repeated warming and cooling down of MPT/LPD revealed good reproducibility of viscosity change. Injection pressure through either microcatheter showed significant reduction when MPT/LPD was warmed (P < 0.05, Spearman's rank correlation coefficient). CONCLUSION: The viscosity and injection pressure through microcatheters of MPT/LPD was confirmed to reduce significantly as the temperature is elevated. MPT/LPD warmed to 40°C has half viscosity as that at room temperature and is considered suitable for clinical use. Warming MPT/LPD may have potential to facilitate the procedure of TACE for HCC.

Warming effect on miriplatin-lipiodol suspension as a chemotherapeutic agent for transarterial chemoembolization for hepatocellular carcinoma: preliminary clinical experience.

PURPOSE: To retrospectively elucidate the preliminary clinical impact of warmed miriplatin-lipiodol suspension (MPT-LPD) when used as a chemotherapeutic agent for transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Between June and December 2010, TACE was performed with MPT-LPD at room temperature (RT group), and after January 2011, TACE with MPT-LPD warmed to 40 °C was performed (W group). The intraarterial appearance of MPT-LPD immediately after injection through microcatheters at the second-order branches was compared between the two groups with a 5-point grading system. Local therapeutic effects of HCCs as assessed by follow-up computed tomography (CT) obtained 1-3 months after TACE were compared between the groups with a 4-point grading system (TE1-TE4). After April 2011, angiography-assisted CT was routinely performed at TACE, and HCCs that revealed apparent corona enhancement (CE) were retrospectively selected. The degree of concordance between CE and MPT-LPD accumulation as assessed by CT immediately after TACE was assessed with a 3-point grading scale. RESULTS: MPT-LPD therapy resulted in a smooth and continuous appearance in the W group (grades 1, 2, 3, 4, and 5 were, respectively, 1, 2, 11, 18, and 4) compared to the RT group (4, 0, 1, 2, and 0). The W group (TE1, TE2, TE3, and TE4 were 1, 9, 11, and 12) revealed better local therapeutic effects than the RT group (6, 3, 9, and 0) (p < 0.05). CE was found in 26 HCC nodules, and concordance between CE and MPT-LPD accumulation was observed in 66% (grades 1, 2, and 3 were, respectively, 2, 8, and 19). CONCLUSION: Warmed MPT-LPD flowed more smoothly within vascular lumen, passed through tumor sinusoid of HCC, and had better local therapeutic effects at short-term observation than MPT-LPD at room temperature.

Papillary renal cell carcinoma with extensive paraaortic nodal metastasis mimicking malignant lymphoma.

A 52-year-old woman with abdominal distension underwent computed tomography (CT) that demonstrated extensive paraaortic lymphadenopathy and a right renal mass. Compared to the renal cortex, the lesions exhibited low signal intensity on T(1)- and T(2)-weighted images and high intensity on diffusion-weighted magnetic resonance (MR) images. We suspected malignant lymphoma and performed excisional biopsy, which revealed metastatic papillary renal cell carcinoma. Retrospectively, significantly reduced signal on in-phase chemical shift MR images compared to out-of-phase images suggested the presence of intratumoral hemosiderin, a characteristic finding of this entity.