Stratification of prostate cancer patients into low- and high-grade groups using multiparametric magnetic resonance radiomics with dynamic contrast-enhanced image joint histograms.

PURPOSE: This study aimed to investigate the potential of stratification of prostate cancer patients into low- and high-grade groups (GGs) using multiparametric magnetic resonance (mpMR) radiomics in conjunction with two-dimensional (2D) joint histograms computed with dynamic contrast-enhanced (DCE) images. METHODS: A total of 101 prostate cancer regions extracted from the MR images of 44 patients were identified and divided into training (n = 31 with 72 cancer regions) and test datasets (n = 13 with 29 cancer regions). Each dataset included low-grade tumors (International Society of Urological Pathology [ISUP] GG ≤ 2) and high-grade tumors (ISUP GG ≥ 3). A total of 137,970 features consisted of mpMR image (16 types of images in four sequences)-based and joint histogram (DCE images at 10 phases)-based features for each cancer region. Joint histogram features can visualize temporally changing perfusion patterns in prostate cancer based on the joint histograms between different phases or subtraction phases of DCE images. Nine signatures (a set of significant features related to GGs) were determined using the best combinations of features selected using the least absolute shrinkage and selection operator. Further, support vector machine models with the nine signatures were built based on a leave-one-out cross-validation for the training dataset and evaluated with receiver operating characteristic (ROC) curve analysis. RESULTS: The signature showing the best performance was constructed using six features derived from the joint histograms, DCE original images, and apparent diffusion coefficient maps. The areas under the ROC curves for the training and test datasets were 1.00 and 0.985, respectively. CONCLUSION: This study suggests that the proposed approach with mpMR radiomics in conjunction with 2D joint histogram computed with DCE images could have the potential to stratify prostate cancer patients into low- and high-GGs.

Image quality improvement with deep learning-based reconstruction on abdominal ultrahigh-resolution CT: A phantom study.

PURPOSE: In an ultrahigh-resolution CT (U-HRCT), deep learning-based reconstruction (DLR) is expected to drastically reduce image noise without degrading spatial resolution. We assessed a new algorithm's effect on image quality at different radiation doses assuming an abdominal CT protocol. METHODS: For the normal-sized abdominal models, a Catphan 600 was scanned by U-HRCT with 100%, 50%, and 25% radiation doses. In all acquisitions, DLR was compared to model-based iterative reconstruction (MBIR), filtered back projection (FBP), and hybrid iterative reconstruction (HIR). For the quantitative assessment, we compared image noise, which was defined as the standard deviation of the CT number, and spatial resolution among all reconstruction algorithms. RESULTS: Deep learning-based reconstruction yielded lower image noise than FBP and HIR at each radiation dose. DLR yielded higher image noise than MBIR at the 100% and 50% radiation doses (100%, 50%, DLR: 15.4, 16.9 vs MBIR: 10.2, 15.6 Hounsfield units: HU). However, at the 25% radiation dose, the image noise in DLR was lower than that in MBIR (16.7 vs. 26.6 HU). The spatial frequency at 10% of the modulation transfer function (MTF) in DLR was 1.0 cycles/mm, slightly lower than that in MBIR (1.05 cycles/mm) at the 100% radiation dose. Even when the radiation dose decreased, the spatial frequency at 10% of the MTF of DLR did not change significantly (50% and 25% doses, 0.98 and 0.99 cycles/mm, respectively). CONCLUSION: Deep learning-based reconstruction performs more consistently at decreasing dose in abdominal ultrahigh-resolution CT compared to all other commercially available reconstruction algorithms evaluated.

Surgical Indications for Hepatocellular Carcinoma with Non-hypervascular Hypointense Nodules Detected by Gd-EOB-DTPA-Enhanced MRI.

BACKGROUND: The surgical indication for non-hypervascular hypointense nodules (NHVN) detected incidentally on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) for classical hepatocellular carcinoma (HCC) is unknown. Our aim is to clarify the long-term outcomes in patients with this finding. METHODS: We reviewed the cases of 290 HCC patients, including 66 patients with NHVN, who underwent Gd-EOB-MRI prior to hepatectomy, between October 2008 and December 2017 at our center. We divided the patients into three groups: a no-NHVN group, a treated NHVN group, and an untreated NHVN group. RESULTS: There was no significant difference in (RFS) or overall survival (OS) between the no-NHVN and untreated NHVN groups (p = 0.103 and 0.103, respectively). There was no significant difference between these two groups after propensity score matching. Multivariate analyses showed that microscopic intrahepatic metastases and the size of the main classical HCC, the target tumor, were independent prognostic factors of overall survival, but the presence of non-hypervascular hypointense nodules was not. There was no significant difference in RFS or OS between the treated NHVN and untreated NHVN groups (p = 0.158 and 0.109, respectively). CONCLUSIONS: Non-hypervascular hypointense nodules detected incidentally on Gd-EOB-MRI associated with targeted hypervascular HCC did not reflect prognosis of HCC after hepatectomy. Surgical procedures for classical enhancing HCC may be performed even if non-hypervascular hypointense nodules adjacent to the targeted HCC cannot be removed completely.

Multicenter Cohort Study to Assess the Association between Changes on Imaging and Outcome after Regorafenib Treatment (KSCC1603).

BACKGROUND: Molecular targeted drugs having angiogenesis-inhibiting properties allow the induction of necrosis inside tumors. We retrospectively investigated the relationship between changes on imaging associated with regorafenib (REGO) and treatment outcomes using real-world data. PATIENTS AND METHODS: The eligibility criteria included an ECOG PS of 0-1, a starting dose of 120 or 160 mg/day of REGO, and a duration of treatment of at least 35 days. Regarding changes on imaging, cavitation in lung lesions (CLL), morphologic response of liver lesions (MRL), and change of liver metastasis density (CLD) were evaluated. RESULTS: We finally screened 671 cases, and 226 cases were eligible. In total, 172 and 145 patients had lung and liver metastases, respectively. Among the patients with lung metastasis, CLL was found in 69 patients (40.0%). The median progression-free survival (PFS) of the patients with and those without CLL was 3.2 and 2.4 months, respectively (hazard ratio [HR] = 0.758; 95% confidence interval [CI]: 0.529-1.087), and the median overall survival (OS) of these groups was 10.5 and 8.9 months, respectively (HR = 0.862; 95% CI: 0.579-1.285). MRL and CLD of liver metastasis were analyzed in 145 and 90 patients, respectively. The median OS with and without MRL was 8.9 and 8.2 months, respectively, whereas the median OS with and without CLD was 11.6 and 7.7 months, respectively (HR = 0.523; 95% CI: 0.275-0.992). CONCLUSION: CLL may predict PFS but not OS among patients with lung metastasis. CLD was predictive of favorable outcomes for REGO in patients with liver metastasis.

Gadoxetate disodium-related event during image acquisition: a prospective multi-institutional study for better MR practice.

PURPOSE: To acknowledge the facts of gadoxetate disodium-related events in Japan and to achieve better MR practice by analyzing large cohort data with various MR parameters. MATERIALS AND METHODS: This prospective multi-institutional study included 1993 patients (1201 men, mean age 66.4 ± 12.8 years), who received dynamic MRI with gadoxetate disodium (gadoxetate group, n = 1646) or extracellular gadolinium-based contrast agents (other-GBCAs group, n = 347) between January and November 2016. Recorded data covered adverse reactions including dyspnea, breath-hold failure during acquisition, respiratory artifacts rated with a four-point scale, and MR parameters. We compared data between the two groups in whole cohort and age-, gender-, and institution-matched subcohort using χ2 test (n = 640). Logistic regression model was used to reveal independent associates of substantial artifacts in arterial phase imaging. RESULTS: Transient dyspnea rarely occurred in gadoxetate or other-GBCAs group (both < 1%). Gadoxetate group (vs other-GBCAs group) showed higher rates of breath-hold failure (whole cohort, 18.2% vs 7.7%, p < 0.001; subcohort, 17.6% vs 6.3%, p < 0.001) and substantial artifacts in arterial phase (7.2% vs 2.2%, p = 0.001; 7.4% vs 1.7%, p = 0.001). With single arterial phase protocol, substantial artifacts under gadoxetate were independently associated with age (odds ratio [OR] = 1.04, p < 0.001), hearing difficulty (OR = 2.92, p = 0.008), breath-hold practice required (OR = 1.61, p = 0.039), and short acquisition time (OR = 0.43, p = 0.005). Multiple arterial phase acquisition did not reduce the incident rate of substantial artifacts. CONCLUSION: Gadoxetate disodium was associated with breath-hold failure and substantial artifacts in arterial phase imaging, but not with dyspnea in Japan. Shorter acquisition time should be used to sustain image quality in gadoxetate disodium-enhanced arterial phase imaging. KEY POINTS: • Gadoxetate disodium administration leads to breath-hold failure and substantial imaging artifacts in arterial phase MRI in Japan. • Contrast agent-induced dyspnea in arterial phase and adverse reactions are rare in Japan, without showing differences between gadoxetate disodium or other extracellular gadolinium-based contrast agents. • Shorter acquisition time significantly reduces gadoxetate-induced imaging artifacts in the arterial phase.

Hyperintense Liver Masses at Hepatobiliary Phase Gadoxetic Acid-enhanced MRI: Imaging Appearances and Clinical Importance.

Gadoxetic acid, a hepatobiliary-specific contrast medium used for MRI, is becoming increasingly important in the detection and characterization of hepatic mass lesions. This medium is taken up by functioning hepatocytes, and the liver parenchyma is strongly enhanced in the hepatobiliary phase (HBP), during which hepatic mass lesions without functioning hepatocytes commonly show hypointensity. However, some hepatic mass lesions show hyperintensity in the HBP. Focal nodular hyperplasia (FNH) and FNH-like lesions show hyperintensity in the HBP owing to the uptake of gadoxetic acid by hyperplastic normal hepatocytes. The tumor cells of some types of hepatocellular adenoma (eg, ß-catenin-activated type, inflammatory type) and hepatocellular carcinoma (eg, green hepatoma) can show uptake of gadoxetic acid. Retention of gadoxetic acid in the extracellular space can cause hyperintensity of fibrotic tumors or hemangiomas during the HBP owing to the extracellular contrast agent characteristics of gadoxetic acid. During the HBP, peritumoral retention is observed in some tumors, such as hepatocellular carcinomas, gastrointestinal stromal tumors, and neuroendocrine tumors. Gadoxetic acid is excreted into the bile; therefore, biliary tract enhancement can be observed in the cystic components of intraductal papillary neoplasms of the bile duct. Intratumoral bile ducts can be observed in malignant lymphomas. Knowledge of these specific mechanisms, which can cause hyperintensity during the HBP depending on the pathologic or molecular background, is important not only for precise imaging-based diagnoses but also for understanding the pathogenesis of hepatic mass lesions. ©RSNA, 2019 See discussion on this article by Lalwani.

Improved visualization of a fine intrahepatic biliary duct on drip infusion cholangiography-computed tomography: Impact of knowledge-based iterative model reconstruction.

AIM: The purpose of this study was to investigate the visualization of fine biliary ducts with knowledge-based iterative model reconstruction (IMR) in low-dose drip infusion computed tomography (CT) cholangiography (DIC-CT) as compared with filtered back projection (FBP) and hybrid iterative reconstruction (iDose4 ). METHODS: A total of 38 patients underwent DIC-CT for living donor liver transplantation. CT was performed approximately 20 min after the end of the infusion of meglumine iotroxate (100 mL). Images were reconstructed using FBP, iDose4 , and IMR, and 1-mm slice images at fixed window level and width were prepared for assessment. Two reviewers independently evaluated the quality of visualization of the fine biliary ducts of the caudate lobe (B1) using a 5-point scale. The visualization scores of three reconstructed images were compared using the Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: For reviewer 1, the visualization score of IMR was significantly higher than that of FBP (P = 0.012), and tended to be higher than that of iDose4 (P = 0.078). For reviewer 2, the visualization score of IMR was significantly higher than those of both FBP and iDose4 (P < 0.01). CONCLUSIONS: IMR showed better visualization of B1 on DIC-CT than FBP or iDose4 . DIC-CT reconstructed with IMR may be useful to the anatomical grasp of biliary tracts in cases of hepatectomy.

Amide proton transfer imaging to predict tumor response to neoadjuvant chemotherapy in locally advanced rectal cancer.

BACKGROUND AND AIM: The amount of proteins and peptides can be estimated with amide proton transfer (APT) imaging. Previous studies demonstrated the usefulness of APT imaging to predict tumor malignancy. We determined whether APT imaging can predict the tumor response to neoadjuvant chemotherapy (NAC) in patients with locally advanced rectal cancer (LARC). METHODS: Seventeen patients with LARC who underwent a pretherapeutic magnetic resonance examination including APT imaging and NAC (at least two courses) were enrolled. The APT-weighted imaging (WI) signal intensity (SI) (%) was defined as magnetization transfer ratio asymmetry (MTRasym ) at the offset of 3.5 ppm. Each tumor was histologically evaluated for the degree of degeneration and necrosis and then classified as one of five histological Grades (0, none; 1a, less than 1/3; 1b, 1/3 to 2/3; 2, more than 2/3; 3, all). We compared the mean APTWI SIs of the tumors between the Grade 0/1a/1b (low-response group) and Grade 2/3 (high-response group) by Student's t-test. We used receiver operating characteristics curves to determine the diagnostic performance of the APTWI SI for predicting the tumor response. RESULTS: The mean APTWI SI of the low-response group (n = 12; 3.05 ± 1.61%) was significantly higher than that of the high-response group (n = 5; 1.14 ± 1.13%) (P = 0.029). The area under the curve for predicting the tumor response using the APTWI SI was 0.87. When ≥2.75% was used as an indicator of low-response status, 75% sensitivity and 100% specificity of the APTWI SI were obtained. CONCLUSION: Pretherapeutic APT imaging can predict the tumor response to NAC in patients with LARC.

Amide Proton Transfer MR Imaging of Endometrioid Endometrial Adenocarcinoma: Association with Histologic Grade.

Purpose To evaluate the utility of amide proton transfer (APT) imaging in estimating histologic grades of endometrioid endometrial adenocarcinoma (EEA). Materials and Methods The institutional review board approved this prospective study. Between June 2012 and March 2016, 32 patients with EEA underwent magnetic resonance (MR) imaging. After their surgical procedures, their EEAs were confirmed pathologically and classified into histologic grades: grade 1 (n = 11), grade 2 (n = 11), and grade 3 (n = 10). The APT signal intensities (SIs) and the mean and minimum apparent diffusion coefficients (ADCs) of the three grades were calculated and compared. Spearman rank correlation coefficient was also calculated between the APT SIs and histologic grades, and between the ADCs and histologic grades. Results The Spearman correlation coefficient with histologic grade of the APT SIs, the mean ADC, and the minimum ADC were 0.55 (P = .001), 0.03 (P = .84), and -0.30 (P = .09), respectively. The average APT SIs and the mean and minimum ADCs were 2.2% ± 0.2 (standard deviation), 0.9 × 10-3 mm2/sec ± 0.2, and 0.6 × 10-3 mm2/sec ± 0.1 for grade 1; 3.2% ± 0.3, 0.8 × 10-3 mm2/sec ± 0.1, and 0.5 × 10-3 mm2/sec ± 0.1 for grade 2; and 3.7% ± 0.3, 0.9 × 10-3 mm2/sec ± 0.1, and 0.5 × 10-3 mm2/sec ± 0.1 for grade 3, respectively. The APT SIs of grade 3 EEA were significantly higher than those of grade 1 EEA (P = .01), but other pairwise comparisons did not reveal any significant differences (P = .06-.51). The mean and minimum ADCs showed no significant differences among the three histologic grades (P =.13-.51). Conclusion The APT SI was positively correlated with the histologic grades of EEA. © RSNA, 2017 Online supplemental material is available for this article.

Dynamic flow imaging using 320-detector row CT and motion coherence analysis in coronary aneurysms associated with Kawasaki disease.

Introduction We propose a new dynamic flow imaging using 320-detector row CT, and investigate the assessment of coronary flow in aneurysms of Kawasaki disease in adulthood. METHODS: Six patients with Kawasaki disease and coronary aneurysms associated (26.7 years old) and six controls were enrolled. Dynamic coronary CT angiography with 320-row CT was continuously performed at mid-diastole throughout 15-25 cardiac cycles with prospective Electrocardiogram gating after injection of contrast media. Dynamic data sets of 15-25 cycles were computed into 90-100 data sets by motion coherence image processing. Next, time-density curves for coronary arteries were calculated for all the phases. On the basis of the maximum slope method, coronary flow index was defined as the ratio of the maximum upslope of the attenuation of coronary arteries to the upslope of the attenuation of ascending aorta on the time-density curves. Coronary flow indexes for the proximal and distal sites of coronary arteries and intra-aneurysm were measured.

The prevalence of transpancreatic common hepatic artery and coexisting variant anatomy.

We studied the prevalence of the transpancreatic common hepatic artery (tp-CHA) and coexisting variant anatomy. The study group comprised 788 consecutive liver transplant donor candidates who had undergone thin-section multidetector-row computed tomography (MDCT) studies to investigate vascular anatomy. Multiplanar reformatted (MPR) images obtained from the arterial phase were retrospectively reviewed to assess the presence/absence of the tp-CHA. Five cases of tp-CHA with pancreaticobiliary tumors were also included in an investigation of the presence/absence of variant hepatic arteries, celiac stenosis, and circumportal pancreas. Three of the 788 (0.38%) donor candidates had a tp-CHA. Overall, eight tp-CHA cases were assessed for coexisting variant anatomy. Seven of these eight cases had a hepatomesenteric trunk, six had celiac stenosis, and two had a circumportal pancreas. The prevalence of the tp-CHA was 0.38% (approx. one in 260 in normal populations). A tp-CHA can commonly be associated with a hepatomesenteric trunk and celiac stenosis. A circumportal pancreas can also coexist with a tp-CHA. Clin. Anat. 31:598-604, 2018. © 2017 Wiley Periodicals, Inc.

Mass-forming intrahepatic cholangiocarcinoma: Enhancement patterns in the arterial phase of dynamic hepatic CT - Correlation with clinicopathological findings.

OBJECTIVES: To evaluate the relationship between the enhancement pattern of intrahepatic cholangiocarcinomas (ICCs) in the hepatic arterial phase (HAP) of dynamic hepatic CT and the clinicopathological findings with special reference to the perihilar type and the peripheral type. METHODS: Forty-seven patients with pathologically proven ICCs were enrolled. Based on the enhancement pattern in the HAP, the lesions were classified into three groups: a hypovascular group (n=13), rim-enhancement group (n=18), and hypervascular group (n=16). The clinicopathological findings were compared among the three groups. RESULTS: Perihilar-type ICCs were significantly more frequently observed in the hypovascular group than in the rim-enhancement and hypervascular groups (p=0.006 and p <0.001, respectively). Lymphatic invasion, perineural invasion, and biliary invasion were significantly more frequent in the hypovascular group than the rim- enhancement group (p=0.001, p=0.025 and p=0.029, respectively) or hypervascular group (p <0.001, p <0.001 and p=0.025, respectively). Patients with hypovascular lesions showed significantly poorer disease-free survival than patients with rim-enhancing or hypervascular lesions (p=0.001 and p=0.001, respectively). Hypovascularity was an independent preoperative prognostic factor for disease-free survival (p<0.001). CONCLUSIONS: Hypovascular ICCs in the HAP tend to be of perihilar type and to have more malignant potential than other ICCs. KEY POINTS: • Hypovascular ICCs have greater malignant potential than rim-enhancing and hypervascular ICCs. • Hypovascular ICCs show a higher frequency of perihilar-type ICCs. • Perihilar-type ICCs do not always display distal ductal wall thickening.

Prognostic significance of contrast-enhanced CT attenuation value in extrahepatic cholangiocarcinoma.

OBJECTIVES: To determine whether washout characteristics of dynamic contrast-enhanced computed tomography (CT) could predict survival in patients with extrahepatic cholangiocarcinoma (EHC). METHODS: This study collected 46 resected cases. All cases were examined by dynamic contrast study on multidetector-row CT. Region-of-interest measurements were obtained at the non-enhanced, portal venous phase and delayed phase in the tumour and were used to calculate the washout ratio as follows: [(attenuation value at portal venous phase CT - attenuation value at delayed enhanced CT)/(attenuation value at portal venous phase CT - attenuation value at unenhanced CT)] × 100. On the basis of the median washout ratio, we classified the cases into two groups, a high-washout group and low-washout group. Associations between overall survival and various factors including washout rates were analysed. RESULTS: The median washout ratio was 29.4 %. Univariate analysis revealed that a lower washout ratio, venous invasion, lymphatic permeation and lymph node metastasis were associated with shorter survival. Multivariate analysis identified the lower washout ratio as an independent prognostic factor (hazard ratio, 3.768; p value, 0.027). CONCLUSIONS: The washout ratio obtained from the contrast-enhanced CT may be a useful imaging biomarker for the prediction of survival of patients with EHC. KEY POINTS: • Dynamic contrast study can evaluate the aggressiveness of extrahepatic cholangiocarcinoma. • A lower washout ratio was an independent prognostic factor for overall survival. • CT can predict survival and inform decisions on surgical options or chemotherapy.

Functional remnant liver assessment predicts liver-related morbidity after hepatic resection in patients with hepatocellular carcinoma.

AIM: We aimed to evaluate whether functional assessment of the future remnant liver is a predictor of postoperative morbidity after hepatic resection in patients with hepatocellular carcinoma (HCC). METHODS: One hundred forty-six patients who underwent hepatic resection for HCC were enrolled in this study. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced MRI (EOB-MRI) analysis for functional liver assessment was carried out before hepatic resection. The signal intensity in the remnant liver was measured and divided by the signal intensity of the major psoas muscle (the liver to major psoas muscle ratio, LMR) for standardization. The remnant liver function was calculated using the formula (LMR on the hepatobiliary phase/LMR on the precontrast image). Computed tomography liver volumetry was also carried out. The remnant functional liver was calculated as the remnant liver volume or volumetric rate × remnant liver function by EOB-MRI. RESULTS: Morbidities developed in 19 (13.0%) patients. Morbidities associated with the liver occurred in 7 patients (4.7%). There was no mortality during surgery. Median remnant liver function scores using EOB-MRI and remnant functional liver using volumetric rate or volumetry were 1.82 (range, 1.25-2.96), 155.9 (range, 64.7-285.3), and 1027 (range, 369-2148), respectively. Logistic regression analysis identified the remnant functional liver volume as the only independent predictor for liver-related morbidity. CONCLUSION: Remnant functional liver volume using computed tomography liver volumetry and EOB-MRI was a significantly useful predictor for liver-related morbidity after hepatic resection in patients with HCC.

Apparent diffusion coefficient: An associative factor for recurrence after nephrectomy in localized renal cell carcinoma.

PURPOSE: To investigate whether the apparent diffusion coefficient (ADC) of a tumor is associated with recurrence after nephrectomy in renal cell carcinoma (RCC) MATERIALS AND METHODS: We retrospectively studied 49 patients with localized RCC who underwent 1.5T magnetic resonance imaging (MRI) including diffusion-weighted imaging preoperatively. Fifteen patients had recurrent disease after surgery. The ADC was measured by placing a region-of-interest in a solid region of each tumor on the ADC map. We named the average value of the three ADC values the "average ADC" and the lowest ADC value among the three as the "minimum ADC." The correlations between clinicopathological factors including patient age and gender, tumor side, tumor size, growth/invasion pattern, Fuhrman grade, histological subtype, venous invasion, average and minimum ADCs, and disease-free survival were analyzed by Cox proportional hazards model. RESULTS: In univariate analysis, tumor size, venous invasion, mean ADC, and minimum ADC showed significant correlations with disease-free survival (P < 0.05). In multivariate analysis, only venous invasion and minimum ADC were significant (P < 0.05). The 5-year disease-free survival rate of the low minimum ADC group was 51.6%, while that of the high minimum ADC group was 85.1%. CONCLUSION: The minimum ADC of a tumor, although not as pronounced as venous invasion, was found to be an independent associative factor for recurrence after nephrectomy in patients with localized RCC.

Differentiation of early gastric cancer with ulceration and resectable advanced gastric cancer using multiphasic dynamic multidetector CT.

OBJECTIVES: Early gastric cancer with ulceration (EGC-U) mimics advanced gastric cancer (AGC), as EGC-Us and ACGs often have similar endoscopic appearance to ulceration. The purpose of this retrospective study was to determine whether multiphasic dynamic multidetector CT (MDCT) can help differentiate EGC-Us from AGCs. METHODS: Patients with EGC-Us with ulcer stages Ul-III or IV and AGCs with tumour stages T2 to T4a were enrolled. MDCT images were obtained 40 s (arterial phase), 70 s (portal phase) and 240 s (delayed phase) after injection of non-ionic contrast material. Two readers independently measured the attenuation values of the lesions by placing regions of interest. We compared the EGC-Us and AGCs using the mean attenuation values in each phase and peak enhancement phase. We analysed the diagnostic performance of CT for differentiating EGC-Us from AGCs. RESULTS: Forty cases (16 EGC-Us and 24 AGCs) were analysed. The mean attenuation values of the EGC-Us were significantly lower than those of the AGCs in both the arterial and portal phases (all p < 0.0001 for each reader). The peak enhancement was significantly different between the EGC-Us and AGCs for both readers (Reader 1, p = 0.0131; Reader 2, p = 0.0006). CONCLUSION: Multiphasic dynamic contrast-enhanced MDCT can help differentiate EGC-Us from AGCs. KEY POINTS: • Early gastric cancer with ulceration and advanced gastric cancer have similar endoscopic appearances. • EGC-U shows significantly lower attenuation values in both arterial and portal phases. • Multiphasic dynamic contrast-enhanced MDCT differentiates EGC-U from AGC.

Skeletal muscle mass assessed by computed tomography correlates to muscle strength and physical performance at a liver-related hospital experience.

AIM: We aimed to evaluate whether skeletal muscle mass measured by computed tomography (CT) or bioelectrical impedance analysis (BIA) correlated to muscle strength and physical performance in liver-related hospital cases. METHODS: We prospectively conducted this study in 120 liver-related hospital cases. Skeletal muscle mass was measured by CT scan and BIA. Muscle strength was determined by hand grip strength and physical performance by usual gait speed. RESULTS: Skeletal muscle mass measured using CT significantly correlated to usual gait speed (r(2) = 0.17, P < 0.0001) and hand grip strength (r(2) = 0.66, P < 0.0001), but the correlations were lower using BIA (r(2) = 0.1, P = 0.0005; r(2) = 0.54, P < 0.0001). With regard to liver function, the relationship between skeletal muscle mass measured by CT and BIA and two muscle function parameters in the Child-Pugh A group were significant. In contrast, skeletal muscle mass measured by BIA in the Child-Pugh B or C group was not significantly related to usual gait speed. CONCLUSION: Skeletal muscle mass measured by CT was significantly correlated to hand grip strength and usual gait speed, with higher correlations compared with BIA. Moreover, skeletal muscle mass measured by CT significantly correlated with two muscle functions, even in patients with Child-Pugh B or C.

Amide proton transfer (APT) magnetic resonance imaging of prostate cancer: comparison with Gleason scores.

OBJECTIVE: To evaluate the utility of amide proton transfer (APT) imaging in estimating the Gleason score (GS) of prostate cancer (Pca). MATERIALS AND METHODS: Sixty-six biopsy-proven cancers were categorized into four groups according to the GS: GS-6 (3 + 3); GS-7 (3 + 4/4 + 3); GS-8 (4 + 4) and GS-9 (4 + 5/5 + 4). APT signal intensities (APT SIs) and apparent diffusion coefficient (ADC) values of each GS group were compared by one-way analysis of variance with Tukey's HSD post hoc test. RESULTS: The mean and standard deviation of the APT SIs (%) and ADC values (×10(-3) mm(2)/s) were as follows: GS-6, 2.48 ± 0.59 and 1.16 ± 0.26; GS-7, 5.17 ± 0.66 and 0.92 ± 0.18; GS-8, 2.56 ± 0.85 and 0.86 ± 0.17; GS-9, 1.96 ± 0.75 and 0.85 ± 0.18, respectively. The APT SI of the GS-7 group was highest, and there were significant differences between the GS-6 and GS-7 groups and the GS-7 and GS-9 groups (p < 0.05). The ADC value of the GS-6 group was significantly higher than each value of the GS-7, GS-8, and GS-9 groups (p < 0.05), but no significant differences were obtained among the GS-7, GS-8, and GS-9 groups. CONCLUSION: The mean APT SI in Pca with a GS of 7 was higher than that for the other GS groups.

T1 ρ Relaxation of the liver: A potential biomarker of liver function.

PURPOSE: To investigate the diagnostic potential of T1 ρ relaxation for assessing liver function, liver fibrosis, or liver necroinflammation in patients with chronic liver disease (CLD). MATERIALS AND METHODS: We obtained T1 ρ maps of the liver for 53 patients with or without CLD. We measured the T1 ρ values of the liver and correlated them with the results of laboratory tests and histological examinations. Pearson's correlation coefficients (r) were calculated between the T1 ρ values and blood serum parameters including the retention rates at 15 minutes after an injection of indocyanine green (ICG-R15). Spearman's rank correlation coefficients were calculated between the T1 ρ values and the scores of liver fibrosis or liver necroinflammation. RESULTS: The T1 ρ values showed significant positive correlations with the serum levels of total bilirubin (r = 0.31, P < 0.05), direct bilirubin (r = 0.32, P < 0.05), and ICG-R15 (r = 0.46, P < 0.05), and significant negative correlations with the serum levels of albumin (r = -0.33, P < 0.05) and γ-glutamyl transpeptidase (r = -0.28, P < 0.05). However, there were no significant correlations between the T1 ρ value and the scores of liver fibrosis (P = 0.95) or liver necroinflammation (P = 0.86). CONCLUSION: T1 ρ relaxation has potential as a biomarker of liver function in patients with CLD. However, it may not be suitable to estimate liver fibrosis or liver necroinflammation.

Three-dimensional T2-weighted imaging for liver MRI: clinical values of tissue-specific variable refocusing flip-angle turbo spin echo imaging.

PURPOSE: To assess the clinical utility of tissue-specific variable refocusing flip-angle (VRFA) turbo-spin echo imaging for three-dimensional T2-weighted imaging (3D-T2WI) of the liver. MATERIALS AND METHODS: Fifty-nine patients were scanned with three types of fat-suppressed T2WI for the comparison: two-dimensional single-shot turbo spin echo T2WI (ssT2WI), 3D-T2WI with tissue-specific VRFA (VISTA-TSV), and 3D-T2WI with low-constant VRFA (VISTA). Qualitatively, artifacts in the left and right lobes of the liver and black-blood effects in the liver were compared using the Wilcoxon signed-rank test with the Bonferroni correction. The detection and correct characterization rates of liver lesions were compared using McNemar's test. RESULTS: VISTA-TSV showed reduced artifacts in the left and right lobes of the liver compared with VISTA (P < 0.017). The artifacts shown by VISTA-TSV were equivalent to those shown by ssT2WI. The black-blood effects of VISTA-TSV and VISTA were better than that of ssT2WI (P < 0.017). VISTA-TSV showed the best detection and correct characterization rate of liver lesions among the three imaging techniques (P < 0.05). CONCLUSION: 3D-T2WI with tissue-specific VRFA can reduce artifacts of the liver, sufficiently suppress the signal in blood vessels, and has a potential to improve the detection and correct characterization rates of liver lesions.