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Purpose: To reveal that a computed tomography surveillance program (CT-surveillance) could demonstrate the epidemiologic features of COVID-19 infection and simultaneously investigate the type and frequency of CT findings using clinical CT data., Materials and Methods: We targeted individuals with possible CT findings of viral pneumonia. Using an online questionnaire, we asked Japanese board-certified radiologists to register their patients' information including patient age and sex, the CT examination date, the results of PCR test for COVID-19 infection, CT findings, and the postal code of the medical institution that performed the CT. We compared the diurnal patient number and the cumulative regional distribution map of registrations in CT-surveillance to those of the PCR-positive patient surveillance (PCR-surveillance)., Results: A total of 637 patients was registered from January 1 to April 17, 2020 for CT-surveillance. Their PCR test results were positive (n = 62.5-398%), negative (n = 8.9-57%), unknown (n = 26.2-167%), and other disease (n = 2.4-15%). An age peak at 60-69 years and male dominance were observed in CT-surveillance. The most common CT finding was bilaterally distributed ground-glass opacities. The diurnal number and the cumulative regional distribution map by CT-surveillance showed tendencies that were similar to those revealed by PCR-surveillance., Conclusion: Using clinical CT data, CT-surveillance program delineated the epidemiologic features of COVID-19 infection.

We evaluated the changes of gadoxetic acid uptake of the liver parenchyma after hepatitis C virus (HCV) eradication by direct-antiviral agent (DAA) therapy. The increase rate of the liver-to-muscle signal intensity ratio, the skewness and the kurtosis were calculated in the hepatobiliary phase. After sustained virological response, gadoxetic acid uptake of the liver parenchyma increased, but became heterogeneous. Our study proved that HCV eradication by DAA therapy could significantly affect gadoxetic acid uptake.

Competing Interests: Declaration of Competing Interest None.

Background: Solid pseudopapillary neoplasm (SPN) of the pancreas is an extremely rare neoplasm with a favorable prognosis. On the other hand, pancreatic invasive ductal carcinoma (IDC) is known to be an aggressive malignancy. To the best of our knowledge, there is no report of SPN combined with IDC of the pancreas., Case Presentation: A 66-year-old woman presented with abnormal genital bleeding and was diagnosed with inoperable cervical cancer. During computed tomography for cancer staging, the patient was incidentally diagnosed with pancreatic cancer. After radiation therapy for the cervical cancer, distal pancreatectomy with D2 lymph node dissection was performed. A postoperative pathological examination revealed SPN with ossification and well-differentiated IDC in the pancreatic body. On immunohistochemical staining, SPN tumor cells showed positive β-catenin and CD10 staining, whereas IDC cells were negative for both. The tumor boundaries were clear. Accordingly, the final pathological diagnosis was synchronous SPN and IDC of the pancreas. Moreover, pathological findings such as the ossification and small number of SPN cells suggested that SPN may have existed long before IDC initiation., Conclusions: Here, we report the first case of SPN combined with IDC of the pancreas. They may occur independently, and the long-term presence of SPN may lead to the development of IDC.

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 (iDose 4 )., 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, iDose 4 , 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 iDose 4 (P = 0.078). For reviewer 2, the visualization score of IMR was significantly higher than those of both FBP and iDose 4 (P < 0.01)., Conclusions: IMR showed better visualization of B1 on DIC-CT than FBP or iDose 4 . DIC-CT reconstructed with IMR may be useful to the anatomical grasp of biliary tracts in cases of hepatectomy., (© 2019 The Japan Society of Hepatology.)

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, β-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.

Purpose: To investigate whether amide proton transfer (APT) imaging is useful to differentiate benign ovarian cystic lesions., Materials and Methods: This prospective study enrolled a total of 19 lesions in 18 patients with benign ovarian cystic lesion: serous cystadenoma (SCA), n = 4; mucinous cystadenoma (MCA), n = 9; or functional cyst (FC), n = 6. APT imaging was performed with three different presaturation pulse durations: 0.5, 1.0 and 2.0 s. APT signal was defined as magnetization transfer ratio asymmetry at 3.5 ppm. The SI ratios of cyst to muscle calculated on T1- and T2-weighted images were defined as T1- and T2-ratios. Apparent diffusion coefficient (ADC) maps were also generated. We compared the three cystic lesion groups' APT signals, T1-ratio, T2-ratio, and ADC., Results: When using 2.0 s of presaturation, the APT signals were 1.41 ± 0.71% in SCA, 5.15 ± 1.92% in MCA and 8.52 ± 1.17% in FC. Significant differences were observed between SCA and MCA (p < .01) and MCA and FC (p < .05), as well as between SCA and FC (P <  .0001). When 1.0 s presaturation pulse was used, similar results were obtained. On the other hand, ADC value shows significance only between SCA (2.91±0.03×10 -3  mm 2 /s) and MCA (2.59 ± 0.49 × 10 -3  mm 2 /s, p < .05). Further, there was no significant difference in the T1-ratio, T2-ratio among the three groups., Conclusions: APT imaging might be useful for the non-invasive diagnosis of benign ovarian cystic lesions. With the use of the longer presaturation pulse as possible, APT imaging may provide an early and correct diagnosis of ovarian cystic lesions without additional follow-up studies., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Introduction: The purpose of this retrospective study was to evaluate imaging features of undifferentiated carcinoma of the pancreas., Methods: The study group included eight patients with surgically resected undifferentiated carcinoma of the pancreas. Multidetector-row computed tomography (MDCT, n = 8) and magnetic resonance imaging (MRI, n = 6) findings were retrospectively reviewed., Results: On MDCT, all eight cases were hypovascular with upstream main pancreatic duct (MPD) dilatation, and only 1 showed exophytic growth. Five cases (62.5%) showed necrosis/cystic change, and calcification was observed in two cases (25%). Calcification reflected tumour osteoid components. On MRI, haemorrhage and hemosiderin were observed in 4 of 6 (66.7%) cases. In addition, tumour thrombus in the splenic vein (n = 1) and intraductal tumour growth in the MPD (n = 2) were pathologically identified, although imaging studies only revealed 1 of these latter cases., Conclusion: Undifferentiated carcinoma of the pancreas may present as a tumour with haemorrhagic necrosis. Coexistence of calcification, intraductal tumour growth in the MPD and tumour thrombus may support the imaging diagnosis of this entity., (© 2019 The Royal Australian and New Zealand College of Radiologists.)

Purpose: To evaluate the diagnostic performance of superparamagnetic iron-oxide (SPIO)-enhanced diffusion-weighted image (DWI) for distinguishing an intrapancreatic accessory spleen from pancreatic tumors., Materials and Methods: Twenty-six cases of intrapancreatic accessory spleen and nine cases of pancreatic tail tumors [neuroendocrine tumor (n = 8) and pancreatic adenocarcinoma (n = 1)] were analyzed. Two blind reviewers retrospectively reviewed the SPIO-enhanced magnetic resonance imaging (MRI) scans. The lesion visibility grades were compared and the diagnostic performance of SPIO-enhanced DWI was compared to those of SPIO-enhanced T2WI and T2*WI with the use of a receiver operating characteristic (ROC) analysis., Results: The grade of lesion visibility was the highest on DWI [mean ± standard deviation (SD): 2.8 ± 0.3] followed by T2WI (2.3 ± 0.7, p < 0.001) and T2*WI (2.1 ± 0.7, p < 0.0001). Reviewers 1 and 2 correctly characterized the presence or absence of SPIO uptake in 34 of 35 cases (97.1%) on DWI, 24 (68.6%) and 25 (71.4%) cases on T2WI, respectively, and 16 (45.7%) and 17 (48.6%) cases on T2*WI. The area under the ROC curve (AUC) of DWI was 0.974 and 0.989 for reviewers 1 and 2, respectively. For Reviewer 1, the AUC of DWI was significantly higher than that of T2*WI (0.756, p < 0.01), although it was not significantly different from that of T2WI (0.868, p = 0.0857). For Reviewer 2, the AUC of DWI was significantly higher than those of T2WI (0.846, p < 0.05) and T2*WI (0.803, p < 0.01)., Conclusion: The diagnostic performance of SPIO-enhanced DWI was better than those of SPIO-enhanced T2*WI and T2WI for the diagnosis of intrapancreatic accessory spleen.

Aim: To compare perfusion computed tomography (CT) with reconstructed image from source data using low-dose contrast agent and conventional 320-row CT for the evaluation of renal tumours., Materials and Methods: Twenty-eight patients underwent conventional CT (C-CT) and 26 patients underwent perfusion CT with low-dose (40 ml) contrast agent. Image noise, arterial visualisation, the sharpness of the corticomedullary junction (CMJ), and overall image quality were each assessed using a four-point scale. The tumour detection rate for lesions <4 cm (n=66) was also evaluated. Quantitative image parameters including image noise and the contrast-to-noise ratios (CNRs) of the renal artery and CMJ were measured. The volume CT dose index (CTDI), dose-length product (DLP), and size-specific dose estimate (SSDE) were also recorded., Results: Although the image noise of perfusion CT was higher than that of C-CT and the overall image quality of perfusion CT was lower than that of C-CT, the arterial visualisation score of perfusion CT was significantly higher than that of C-CT. The CMJ sharpness scores of the two techniques were equivalent. Sensitivity and positive predictive values were also equivalent with respect to tumour detection. The CNRs of both the left and right renal arteries were significantly higher on perfusion CT than on C-CT. The CTDI, DLP, and SSDE of perfusion CT were significantly lower than those of C-CT., Conclusion: Perfusion CT using low-dose contrast agent preserved arterial visualisation and the tumour detection rate and achieved a low radiation dose despite image quality degradation and image noise., (Copyright © 2019 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Purpose: We investigated the usefulness of the modified RENAL nephrometry (mRN) scoring system for predicting post-cryotherapy renal function in patients with T1a renal mass., Patients and Methods: A total of 75 patients with a T1a renal mass were enrolled. The mRN score was determined based on the tumor size, the tumor's exophytic/endophytic properties, the tumor's nearness to the collecting system, and the anterior/posterior location of the kidney. The change in the estimated glomerular filtration rate (ΔeGFR) was calculated as follows: ΔeGFR = 100 × ([pretreatment eGFR - eGFR at 6 months after cryotherapy]/pretreatment eGFR). Based on the ΔeGFR results, we classified the patients into two groups: a preserved renal function group (ΔeGFR < 10%) and an impaired renal function group (ΔeGFR ≥ 10%). We then analyzed the relationships between the mRN score and ΔeGFR and between the mRN score and the chronic kidney disease (CKD) stage., Results: The mean ΔeGFR for all patients was 5.5%. The mRN scores of the preserved renal function group (5.8 ± 0.3) were significantly lower than those of the impaired group (7.4 ± 0.3) (p < 0.001). When the mRN score cutoff value was set at 7 points, the mRN had 67.7% sensitivity, 72.7% specificity, 61.8% positive predictive value (PPV), 76.1% negative predictive value (NPV), and 70.7% accuracy for predicting impaired renal function. For predicting a deterioration of CKD stage, the mRN had 92.9% sensitivity, 67.2% specificity, 39.4% PPV, 97.6% NPV, and 72% accuracy., Conclusion: Our newly proposed modified RENAL nephrometry score was suggested to be useful for predicting renal function after renal cryotherapy.

Background: Accumulation of evidence suggests that neoadjuvant chemotherapy improves the outcomes of borderline resectable pancreatic cancer (BRPC). Gemcitabine plus nab-paclitaxel (GnP) has been widely accepted as systemic chemotherapy for unresectable pancreatic cancer and reportedly results in remarkable tumor shrinkage. This study was performed to evaluate the safety and efficacy of neoadjuvant chemotherapy using neoadjuvant GnP for BRPC., Methods: The medical records of 57 patients who underwent treatment of BRPC from 2010 to 2017 were retrospectively reviewed. The patient characteristics and short- and intermediate-term outcomes were compared between the GnP and upfront surgery (UFS) groups., Results: The GnP group comprised 31 patients and the UFS group comprised 26 patients. The patient characteristics were comparable with the exception of a higher prevalence of arterial involvement in the GnP group. Twenty-seven of the 31 patients (87%) in the GnP group and all 26 patients in the UFS group underwent resection. The GnP group showed a significantly shorter operation time (429 vs. 509.5 min, p = 0.0068), less blood loss (760 vs. 1324 ml, p = 0.0115), and a higher R0 resection rate (100% vs. 77%, p = 0.0100) than the UFS group. Postoperative complications and hospital stay were comparable between the two groups, and no treatment-related mortality occurred in either group. Both the disease-free survival and overall survival times were significantly longer in the GnP group (p = 0.0018 and p = 0.0024, respectively)., Conclusions: Neoadjuvant GnP is a safe and effective treatment strategy for BRPC. It potentially improves patients' prognosis and facilitates surgical procedures.

Aim: To investigate whether liver fibrosis can be predicted by quantifying the deformity of the liver obtained based on computed tomographic (CT) images scanned under respiratory control., Materials and Methods: For dynamic CT of 47 patients, portal venous and equilibrium phases were scanned during inspiration and expiration, respectively. After rigid registration of the two images, non-rigid registration of the liver was performed, and the amount and direction of each voxel's shift during non-rigid registration was defined as the deformation vector. The correlation of each CT parameter for the obtained deformation vectors with the pathologically-proven degree of liver fibrosis was assessed using Spearman's rank correlation test. Receiver operating characteristic curve analysis was conducted for prediction of liver fibrosis., Results: The standard deviation, coefficient of variance (CV) and skewness were significantly negatively correlated with the degree of liver fibrosis (p=0.030, 0.009 and 0.037, respectively). Of these measures, CV was best correlated and significantly decreased as liver fibrosis progressed (rho=-0.376). CV showed accuracies of 66.0-70.2%, and the areas under curves were 0.654-0.727 for prediction of fibrosis of grade F1 or greater, F2 or greater, F3 or greater and F4 fibrosis., Conclusion: The deformation vector is a potential CT parameter for evaluating liver fibrosis., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objective: To investigate whether lipid metabolism-related factors regulate unenhanced CT attenuation in adrenal adenoma (AA)., Materials and Methods: Thirty-six patients with surgically proven AAs were enrolled in this study. The patients' underlying diseases were the following: primary aldosteronism (n = 24), Cushing's syndrome (n = 8), subclinical Cushing's syndrome (n = 3) and non-functioning AA (n = 1). Unenhanced CT attenuation of AAs and liver was measured. Pathologically, clear cell ratio (CCR) constituting each AA was qualitatively assessed. Clinical data including tumor diameter, body mass index (BMI), hemoglobin A1c, triglyceride, total cholesterol, blood cortisol and plasma aldosterone levels were also obtained. Simple and multiple linear regression analyses were performed to evaluate the radiological and clinicopathological factors associated with CT attenuation of AAs for all patients and separately for 25 patients with primary aldosteronism or non-functioning AA., Results: For all patients, there was a significant correlation between CT attenuation and each of CCR, BMI and blood cortisol levels (p < 0.05). For patients with primary aldosteronism or non-functioning AA, there was also a significant correlation between CT attenuation and CCR or BMI (p < 0.05)., Conclusion: In addition to pathological factors, lipid-metabolism-related factors including BMI and blood cortisol levels can affect unenhanced CT attenuation of AA., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Purpose: The purpose of this retrospective study was to evaluate imaging features of mucinous nonneoplastic cyst (MNNC) of the pancreas., Materials and Methods: Three (0.9%) patients with MNNC of the pancreas were found in 335 surgically resected pancreatic cystic lesions. Three MDCT and two MRI/MRCP studies were retrospectively reviewed., Results: Three cases of MNNC were found in the pancreatic neck, body, and tail, respectively. All the three cases were multilocular without communication with the main pancreatic duct (MPD), although upstream MPD dilatation was seen in two of the three cases. The signal intensity of the cyst fluid was low on T1-weighted, high on T2-weighted, and low on diffusion-weighted images. Cyst wall was thin in two cases, and the remaining case with obstructive pancreatitis showed visible cyst wall enhancement., Conclusion: Imaging findings of MNNC of the pancreas were nonspecific without communication with the MPD. Cyst wall is typically thin without visible enhancement.

Aim: To retrospectively evaluate the diagnostic performance of free-breathing diffusion-weighted imaging (FB-DWI) with modified imaging parameter settings for detecting hepatocellular carcinomas (HCCs)., Methods: Fifty-one patients at risk for HCC were scanned with both FB-DWI and respiratory-triggered DWI with the navigator echo respiratory-triggering technique (RT-DWI). Qualitatively, the sharpness of the liver contour, the image noise and the chemical shift artifacts on each DWI with b -values of 1000 s/mm 2 were independently evaluated by three radiologists using 4-point scoring. We compared the image quality scores of each observer between the two DWI methods, using the Wilcoxon signed-rank test. Quantitatively, we compared the signal-to-noise ratios (SNRs) of the liver parenchyma and lesion-to-nonlesion contrast-to-noise ratios (CNRs) after measuring the signal intensity on each DWI with a b-factor of 1000 s/mm 2 . The average SNRs and CNRs between the two DWI methods were compared by the paired t-test. The detectability of HCC on each DWI was also analyzed by three radiologists. The detectability provided by the two DWI methods was compared using McNemar's test., Results: For all observers, the averaged image quality scores of FB-DWI were: Sharpness of the liver contour [observer (Obs)-1, 3.08 ± 0.81; Obs-2, 2.98 ± 0.73; Obs-3, 3.54 ± 0.75], those of the distortion (Obs-1, 2.94 ± 0.50; Obs-2, 2.71 ± 0.70; Obs-3, 3.27 ± 0.53), and the chemical shift artifacts (Obs-1, 3.38 ± 0.60; Obs-2, 3.15 ± 1.07; Obs-3, 3.21 ± 0.85). The averaged image quality scores of RT-DWI were: Sharpness of the liver contour (Obs-1, 2.33 ± 0.65; Obs-2, 2.37 ± 0.74; Obs-3, 2.75 ± 0.81), distortion (Obs-1, 2.81 ± 0.56; Obs-2, 2.25 ± 0.74; Obs-3, 2.96 ± 0.71), and the chemical shift artifacts (Obs-1, 2.92 ± 0.59; Obs-2, 2.21 ± 0.85; Obs-3, 2.77 ± 1.08). All image quality scores of FB-DWI were significantly higher than those of RT-DWI ( P < 0.05). The average SNR of the normal liver parenchyma by FB-DWI (11.0 ± 4.8) was not significantly different from that shown by RT-DWI (11.0 ± 5.0); nor were the lesion-to-nonlesion CNRs significantly different (FB-DWI, 21.4 ± 17.7; RT-DWI, 20.1 ± 15.1). For all three observers, the detectability of FB-DWI (Obs-1, 43.6%; Obs-2, 53.6%; and Obs-3, 45.0%) was significantly higher than that of RT-DWI (Obs-1, 29.1%; Obs-2, 43.6%; and Obs-3, 34.5%) ( P < 0.05)., Conclusion: FB-DWI showed better image quality and higher detectability of HCC compared to RT-DWI, without significantly reducing the SNRs of the liver parenchyma and lesion-to-nonlesion CNRs., Competing Interests: Conflict-of-interest statement: We have no financial relationships to disclose.

Aim: To evaluate the effectiveness of motion-sensitised driven-equilibrium (MSDE)-prepared balanced magnetic resonance cholangiopancreatography (MRCP) in a gadolinium ethoxybenzyl diethylene triamine pentaacetic acid (Gd-EOB-DTPA)-enhanced study compared to conventional T2-weighted MRCP., Materials and Methods: Fifteen patients (seven male and eight female patients) prospectively underwent conventional three-dimensional turbo spin-echo T2-weighted MRCP and MSDE-balanced MRCP using a 1.5 T MRI system after hepatobiliary phase image acquisition. For quantitative evaluation, the contrast-to-noise ratio (CNR) of the common hepatic duct to liver tissue was calculated. For qualitative analysis, two radiologists evaluated the depiction of the biliary system and main pancreatic duct (MPD) using a scoring system. Signal suppression of the portal vein (PV) and hepatic vein (HV) on MSDE-balanced MRCP was also scored., Results: MSDE-balanced MRCP showed significantly higher CNR than T2-weighted MRCP. For all biliary structures, the mean depiction scores of MSDE-balanced MRCP were significantly higher than those of T2-weighted MRCP, whereas the mean depiction score of MPD with MSDE-balanced MRCP was significantly lower than that of T2-weighted MRCP. Signal suppression of the PV and HV was thought to be clinically sufficient., Conclusions: MSDE-balanced MRCP more clearly depicted biliary structures compared with T2-weighted MRCP in a Gd-EOB-DTPA-enhanced study. This sequence may be utilised for routine MRCP on Gd-EOB-DTPA-enhanced MRI., (Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this study was to investigate the validity of the management strategy for intraductal papillary mucinous neoplasms (IPMNs) advocated by the international consensus guidelines 2012 (ICG2012)., Methods: The medical records of 49 patients who underwent pancreatectomy for IPMN were retrospectively reviewed., Results: According to preoperative imaging, 10 patients (20 %) had main-duct IPMNs, 20 (41 %) had mixed IPMNs, and 19 (39 %) had branch-duct IPMNs, with malignancy frequencies of 80, 15, and 37 %, respectively. Twenty-seven patients had high-risk stigmata and 21 had worrisome features, with malignancy frequencies of 59 and 10 %, respectively. The sensitivity, specificity, and positive and negative predictive values of high-risk stigmata for malignancy were 88, 65, 59, and 91 %, respectively. Lesions were malignant in 88 % of patients with an enhanced solid component, which was significantly correlated with the prevalence of malignancy (P < 0.01). However, of the 10 patients who underwent pancreatectomy solely due to a main pancreatic dilation of ≥10 mm, 9 (90 %) had benign IPMNs., Conclusions: Many mixed IPMNs defined according to ICG2012 are benign. Although the management strategy advocated by ICG2012 has been improved relative to the Sendai criteria, the different high-risk stigmata carry unequal weights. Consequently, ICG2012 remains suboptimal for predicting malignant IPMN.

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., (© 2015 Wiley Periodicals, Inc.)

Purpose: To show the feasibility of motion-sensitized driven-equilibrium-balanced magnetic resonance cholangiopancreatography and to determine the optimal velocity encoding (VENC) value., Materials and Methods: Sixteen healthy volunteers underwent MRI study using a 1.5-T clinical unit and a 32-channel body array coil. For each volunteer, images were obtained using the following seven respiratory-triggered sequences: (1) balanced magnetic resonance cholangiopancreatography without motion-sensitized driven-equilibrium, and (2)-(7) balanced magnetic resonance cholangiopancreatography with motion-sensitized driven-equilibrium, with VENC=1, 3, 5, 7, 9 and ∞cm/s for the x-, y-, and z-directions, respectively. Quantitative evaluation was obtained by measuring the maximum signal intensity of the common hepatic duct, portal vein, liver tissue including visible peripheral vessels, and liver tissue excluding visible peripheral vessels that were evaluated. We compared the contrast ratios of portal vein/common hepatic duct, liver tissue including visible peripheral vessels/common hepatic duct and liver tissue excluding visible peripheral vessels/common hepatic duct among the five finite sequences (VENC=1, 3, 5, 7, and 9cm/s). Statistical comparisons were performed using the t-test for paired data with the Bonferroni correction., Results: Suppression of blood vessel signals was achieved with motion-sensitized driven-equilibrium sequences. We found the optimal VENC values to be either 3 or 5cm/s with the best suppression of relative vessel signals to bile ducts. At a lower VENC value (1cm/s), the bile duct signal was reduced, presumably due to minimal biliary flow., Conclusion: The feasibility of motion-sensitized driven-equilibrium-balanced magnetic resonance cholangiopancreatography was suggested. The optimal VENC value was considered to be either 3 or 5cm/s. The clinical usefulness of this new magnetic resonance cholangiopancreatography sequence needs to be verified by further studies., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: To clarify the workload of certified radiologists and to estimate the current manpower shortages in Japan., Methods: We conducted a questionnaire survey for accredited training institutions. The contents included the radiologist employment pattern (full vs. part time), the number of computed tomography (CT) and magnetic resonance imaging (MRI) examinations and their radiology reports, the number of radiation therapy planning sessions, and the time per week spent for each work activity. We also used the hospital survey reports of Japan's Ministry of Health, Labor, and Welfare in our analyses., Results: The estimated numbers of CT and MRI interpretation reports and radiation treatment plans that one full-time radiologist could complete within 1 hospital day (8 h) were 19.9 and 1.22, respectively. To complete all CT and MRI reports, at least 2.09 times more full-time diagnostic radiologists are needed in Japan. For radiation therapy, at least 1.23 times more full-time radiation oncologists are necessary at large- and medium-scale hospitals, although the number of radiation oncologists needed in Japan is balanced to the current number., Conclusion: The number of full-time certified diagnostic radiologists for CT and MRI interpretation in Japan is insufficient. Centralized radiation therapy facilities may be more efficient for meeting the increasing demand.

Aim: To clarify the detectability of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI at 3 T with dual-source parallel radiofrequency (RF) excitation., Materials and Methods: Twelve patients with 26 HCCs who each underwent multidetector row CT (MDCT), gadoxetic acid-enhanced MRI with dual-source parallel RF excitation, and angiography-assisted CT prior to living related-liver transplantation. Three blinded readers independently reviewed the images obtained by each imaging technique for the presence of HCC on a segment-by-segment basis using a five-point confidence scale. The area under the receiver operating characteristic curve (Az), sensitivity, and specificity were compared among the three techniques., Results: The Az values of gadoxetic acid-enhanced MRI were highest for all readers, although no significant difference in Az value among the three methods was obtained. No significant differences in sensitivity or specificity were observed among the three techniques for each reader., Conclusion: Gadoxetic acid-enhanced MRI at 3 T with dual-source parallel RF excitation has relatively high-level diagnostic potential for the detection of HCC in patients with severe liver dysfunction, which was equivalent to that of MDCT and angiography-assisted CT. Dual-source parallel RF excitation would have a clinical impact on 3 T MRI of the liver., (Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Purpose: We compared the image quality of free-breathing diffusion-weighted imaging (FB-DWI) to that of respiratory-triggered DWI (RT-DWI) after proper optimization., Materials and Methods: Three healthy subjects were scanned to optimize magnetic resonance (MR) parameters of FB-DWI to improve image quality, including spatial resolution, image noise, and chemical shift artifacts. After this optimization, we scanned 32 patients with liver disease to assess the clinical feasibility of the optimized FB-DWI. Of the 32 patients, 14 had a total of 28 hepatocellular carcinomas (HCCs), four had a total of 15 metastatic liver tumors, and the other 14 had no tumor. Qualitatively, we compared the image quality scores of FB-DWI with those of RT-DWI with the Wilcoxon signed-rank test. Quantitatively, we compared the signal-to-noise ratios (SNRs) of the liver parenchyma, lesion-to-nonlesion contrast-to-noise ratios (CNRs) and apparent diffusion coefficient (ADC) values of the liver parenchyma and liver tumor by the paired t-test., Results: The average scores of image quality for sharpness of liver contour, image noise, and chemical shift artifacts were significantly higher for FB-DWI than RT-DWI (P < 0.05). SNRs, CNRs, and ADC values of the liver parenchyma and tumors did not differ significantly between the 2 DWI methods., Conclusion: Compared with RT-DWI, the optimized FB-DWI provided better spatial resolution, fewer artifacts, and comparable SNRs, lesion-to-nonlesion CNRs, and ADC values.

Purpose: To clarify the diagnostic performance of gadoxetic acid-enhanced MRI for the detection of hepatocellular carcinoma (HCC) in recipients of living related-liver transplantation (LRLT)., Materials and Methods: This retrospective study group consisted of 15 patients with 61 HCCs who each underwent multidetector row computed tomography (MDCT), gadoxetic acid-enhanced MRI, and angiography-assisted computed tomography (CT) before LRLT. The three modalities were compared for their ability to detect HCC. Two blinded readers independently reviewed the images obtained by each modality for the presence of HCC on a segment-by-segment basis using a 5-point confidence scale. The diagnostic performance of the modalities was evaluated in a receiver operating characteristic (ROC) analysis. The area under the ROC curve (Az), sensitivity, specificity, and accuracy were compared for the three modalities., Results: No significant difference in Az, sensitivity, specificity, or accuracy was obtained among gadoxetic acid-enhanced MRI, MDCT, and angiography-assisted CT for both readers. For reader 1, the sensitivity (55.6%) and the accuracy (84.7%) of angiography-assisted CT were significantly higher than those of MDCT (33.3% and 78.0%) (P < 0.05)., Conclusion: Gadoxetic acid-enhanced MRI has a relatively high diagnostic ability to detect HCC even in recipients of LRLT, equivalent to the abilities of MDCT and angiography-assisted CT., (© 2013 Wiley Periodicals, Inc.)

Introduction: The relationship between the washout pattern and constituent cell in adrenal hyperplasia (AH) has not been fully investigated. The purpose of this study was to elucidate the radiological or pathological factors determining the washout pattern of AH on dynamic CT., Methods: Ten patients with 14 surgically proven AHs were enrolled. Dynamic CT was scanned before (pre-contrast image) and 60 seconds (early phase) and 240 seconds (delayed phase) after administration of iodine contrast. The absolute percentage washout (APW) of each nodular lesion was calculated using the following formula: APW(%) = (TAearly-TAdelay)/(TAearly-TApre) × 100, when TApre, TAearly and TAdelay were defined as tumour attenuation values of pre-contrast, early and delayed phases, respectively. Pathologically, the clear cell ratio (CCR) constituting each nodular lesion was qualitatively assessed. Regression analysis was performed to evaluate a correlation between each pair of CCR, TApre, (TAearly-TAdelay) and APW., Results: There was a significant correlation between each pair of CCR, TApre and APW. CCR decreased as TApre increased (r = 0.81, P < 0.001). APW increased as CCR decreased (r = 0.80, P < 0.001) or as TApre increased (r = 0.74, P < 0.01)., Conclusions: The key factors of washout pattern of AH on dynamic CT were CCR and TApre. The difference in constituent cell was associated with variability in APW of AH., (© 2014 The Royal Australian and New Zealand College of Radiologists.)

Purpose: To evaluate if Gd-EOB-DTPA-enhanced MRI could identify liver tissue damage caused by radiation exposure in patients undergoing external beam radiation therapy., Materials and Methods: We enrolled 11 patients who underwent Gd-EOB-DTPA-enhanced MRI during or after radiotherapy in which the radiation field included the liver. External beam radiotherapy was delivered through multiple fields using a 10-MV linear accelerator. The hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI were qualitatively evaluated for the presence of a decreased uptake of Gd-EOB-DTPA in the irradiated area in the liver. Next, signal intensity (SI) ratio of the irradiated area to the non-irradiated liver parenchyma was also calculated. The absorbed dose of the irradiated area in the liver was standardized using equivalent dose in 2Gy fraction (EQD2) and biological effective dose (BED). The results of qualitative analysis were compared with EQD2 or BED, and linear regression analysis was performed between EQD2 or BED and SI ratio., Results: Twenty-two irradiated areas were evaluated. Qualitative analysis revealed a decreased uptake of Gd-EOB-DTPA in 14 areas and no decreased uptake of Gd-EOB-DTPA in eight areas. The thresholds of EQD2 and BED causing a decreased uptake of Gd-EOB-DTPA were considered to be 24 to 29Gy and 29 to 35Gy, respectively. Quantitatively, SI ratio decreased as EQD2 or BED increased (r=0.89, p<0.001), and the inverse relationship between signal enhancement and the absorbed dose in the irradiated area was obtained. One area with EQD2 of 50Gy and BED of 60Gy showed a slightly decreased uptake of Gd-EOB-DTPA on the 40th day but a clearly decreased uptake of Gd-EOB-DTPA on the 123rd day from initiation of radiotherapy., Conclusions: Gd-EOB-DTPA-enhanced MRI described RLI as a decreased uptake of Gd-EOB-DTPA matching the irradiated area. The occurrence of this finding was significantly correlated with the absorbed dose of the irradiated area in the liver., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The role of tumor-associated macrophages (TAMs) in hepatocellular carcinoma (HCC) has not been fully investigated. The aim of the present study was to clarify whether TAMs are associated with the angiogenesis of HCC during its multistep development, especially at an early stage. Forty‑three well-differentiated HCCs and 30 well- to moderately differentiated HCCs (nodule-in-nodule lesion) were used. We immunohistochemically assessed microvessel density (by CD34) and macrophage count (by CD68 or CD163). Computed tomography hepatic angiography (CTHA) was performed for 26 well-differentiated HCCs and all 30 well- to moderately differentiated HCCs. The pathological analysis of the 43 well-differentiated HCCs revealed a positive correlation between microvessel density and macrophage count (p=0.0026, r=0.4486). Based on the CTHA findings, 26 well-differentiated HCCs classified into a hyperattenuation group (n=14) and a hypo- or isoattenuation group (n=12). The microvessel density and macrophage count of the hyperattenuation group were significantly higher than those of the hypo- or isoattenuation group (p=0.0372 and p=0.0476). In the 30 well- to moderately differentiated HCCs, microvessel density of the moderately differentiated components was significantly higher than that of the well-differentiated components (p<0.0001). However, the macrophage count of the moderately differentiated component was significantly lower than that of the well-differentiated component (p<0.0001). All the moderately differentiated components showed marked hyperattenuation on CTHA. Tumor vascularity was correlated with macrophage count in the tumor when limited to well-differentiated HCCs. TAMs may have a role in promoting angiogenesis of HCC at an early stage during its multistep development.

Background and Aim: A faint hypointensity in the noncancerous tissue around hepatocellular carcinoma (HCC) in the hepatobiliary phase of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) is encountered. The goal is to elucidate the significance of this type of pseudolesion designated as the peritumoral decreased uptake area of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) (PDUAE)., Methods: This study group consisted of 61 patients with 61 surgically resected HCCs who underwent preoperative Gd-EOB-DTPA-enhanced MRI. The presence of a faint and hypointense area around the tumor in the hepatobiliary phase was defined as PDUAE. The frequency with which PDUAE was seen was compared between pairs of groups determined by clinical and pathological parameters using a Fisher's exact probability test. The parameters showing significant differences in this test were further tested by multiple logistic regression analysis., Results: PDUAE was observed in 25 cases. In univariate analysis, the values of alpha-fetoprotein and protein-induced by vitamin K absence or antagonist-II, maximal diameter, the presence of a capsule, and vascular invasion were significantly correlated with the frequency with which PDUAE was seen. In multivariate analysis, only maximal diameter and vascular invasion were significantly correlated. When the presence of PDUAE was used as an indicator of vascular invasion, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 72%, 80.6%, 77%, 72%, and 80.6%, respectively., Conclusions: By using this indicator, "microscopic" vascular invasion of HCC can be easily predicted with Gd-EOB-DTPA-enhanced MRI., (© 2013 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Purpose: To elucidate whether the attenuation of hypervascular hepatocellular carcinoma (HCC) on the portal phase of dynamic CT is correlated with histological grade., Materials and Methods: This study group consisted of 66 patients with 74 surgically resected, hypervascular HCCs. On a preoperative dynamic study with a 64-multidetector row CT, the portal phase was scanned 60 s after injecting the contrast agent following the pre-contrast image and hepatic arterial phase. The tumor attenuation of each HCC on the portal phase was categorized into high, iso-, or low, and was compared with the predominant histological grade using Mann-Whitney's U test., Results: Twenty-nine, 29, and 16 HCCs showed high, iso-, and low attenuation on the portal phase, respectively. Tumors were classified into three well- (w-), 58 moderately (m-), or 13 poorly (p-) differentiated HCCs. The tumor attenuation of p-HCC on the portal phase was significantly lower than those of w-HCC and m-HCC (p < 0.05 and p < 0.00001)., Conclusion: The tumor attenuation on the portal phase may help when diagnosing the histological grade of hypervascular HCC. p-HCC are considered to show a faster contrast washout than w-HCC and m-HCC.

Purpose: To evaluate the efficacy of the dual-source parallel radiofrequency system (DS system) for gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI)., Materials and Methods: Twenty-six subjects with liver diseases underwent hepatobiliary phase imaging of Gd-EOB-MRI using either the DS system or a single-source radiofrequency system with or without body-tuned CLEAR, which is a post-processing correction method of B1 inhomogeneity-induced signal loss (SSBTC+ and SSBTC-, respectively). The left and right lobes of the liver were separately assessed. Qualitatively, the homogeneity of signal intensity distribution was scored using a 3-point scale. Quantitatively, lesion-to-liver and spleen-to-liver contrast ratios (CRs) were calculated. The scores and CRs were compared among the three techniques by two-way analysis of variance and Tukey's Honestly Significant Difference post hoc test. Values of p<0.05 were considered statistically significant for each analysis., Results: The DS system showed a significantly better score in the left lobe of the liver, and higher lesion-to-liver and spleen-to-liver CRs in the left and right lobes of the liver, compared with SSBTC+ or SSBTC- (p<0.05). The DS system and SSBTC- showed no significant differences in scores in the right lobe of the liver but they showed significantly better scores than SSBTC+ (p<0.05)., Conclusion: The DS system is more advantageous to improve the homogeneity of signal intensity distribution and tissue contrast of Gd-EOB-MRI than the post-processing correction method independently of the site., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To investigate the predictive factors of malignant transformation of hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase images of gadoxetic acid-enhanced MRI (HHN)., Materials and Methods: The clinical data and imaging findings of dynamic contrast-enhanced computed tomography (DCE-CT) and gadoxetic acid-enhanced MRI for a total of 103 HHNs in 24 patients with chronic liver disease were retrospectively investigated. After the results of follow-up examinations were investigated, HHNs were categorized into the three groups for each comparison: (1) nodules with enlargement and/or vascularization and others, (2) nodules with only enlargement and others, (3) nodules with only vascularization and others. Enlargement and/or vascularization during the follow-up period were defined as malignant transformation of HHN. The frequency of each clinical datum and imaging finding in each group was compared to identify the predictive factors for malignant transformation in HHN., Results: Multivariate analysis showed that a nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI was a significant predictive factor for the enlargement and/or vascularization of HHN (P<0.05). On the other hand, the hypoattenuation on the delayed phase imaging of the initial DCE-CT was a significant predictive factor for the enlargement or vascularization of HHN (P<0.05)., Conclusion: A nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI and hypoattenuation on the delayed phase imaging of initial DCE-CT would be helpful for predicting the outcome of HHN in patients with a risk of hepatocellular carcinoma., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To examine whether the uptake of a liver-specific contrast agent in the liver parenchyma was correlated with the degree of liver fibrosis., Materials and Methods: This retrospective study included 54 and 63 patients who underwent superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI before liver surgery, respectively. For each patient, we calculated ΔR2* and ΔR2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rate of liver-to-spleen signal intensity ratio (LSR) on the hepatobiliary phase compared with the precontrast image. The correlation of each MR parameter with the degree of liver fibrosis (F0 to F4) was assessed using Spearman's rank correlation test., Results: The increase rate of LSR was best correlated with the degree of liver fibrosis and significantly decreased as the liver fibrosis progressed (rho = -0.641; P < 0.0001). It showed sensitivity of 76.9% and specificity of 83.3% in differentiating F3 or greater fibrosis when 1.126 or less was set up as a cut-off value. No significant correlation was obtained between ΔR2* or ΔR2 and the degree of liver fibrosis., Conclusion: The uptake of Gd-EOB-DTPA in the liver parenchyma decreased as the liver fibrosis progressed. J. Magn. Reson. Imaging 2012;36:664-671. © 2012 Wiley Periodicals, Inc., (Copyright © 2012 Wiley-Liss, Inc.)

Aim: To present our initial experience with computed tomography guided radiofrequency ablation (RFA) of osteoid osteoma (OO) in our institution., Methods: RFA was performed on eight patients (5 males and 3 females) with clinically and radiologically diagnosed OO (femoral neck, n = 4; femoral diaphysis, n = 2; tibial diaphysis, n = 1; fibular diaphysis, n = 1). Ablation was performed using an electrode with a 10-mm exposed tip for a total of 4-6 min at a targeted temperature of 90 degrees Celsius. No cooling system was used. The intervention was accepted as technically successful if the tip of the electrode could be placed within the center of the nidus. We defined clinical success as a disappearance within 2 wk after treatment of symptoms that had manifested at presentation., Results: All procedures were technically successful. No major or immediate complications were observed. Clinical success was achieved in six of eight patients in the first procedure. A second procedure was performed for two patients who had recurrent or continued pain, and one of these cases was successfully treated. The overall rate of success was 87.5% (7/8). No complication was observed., Conclusion: Our preliminary results indicate a favorable success rate and no complications and are compatible with the previous reports of RFA of OO.

Purpose: To examine whether or not the parameters regarding the signal intensity of the liver parenchyma on superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI are correlated with the parameters of Technetium-99m galactosyl serum albumin ((99m)Tc-GSA) scintigraphy., Materials and Methods: This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to (99m)Tc-GSA scintigraphy, respectively. For each patient, we calculated Pre R2* and Pre R2, which are equivalent to R2* (=1/T2*) and R2 (=1/T2) values of the liver parenchyma; ΔR2* and ΔR2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rates of both the liver-to-spleen signal intensity ratio (LSR) and the liver-to-major psoas muscle signal intensity ratio (LMR) on the hepatobiliary phase compared with the precontrast image. For (99m)Tc-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded., Results: Regression analysis showed a moderate correlation between Pre R2* and LHL15 (P<0.05). Mild to moderate correlations were also obtained between any combination of ΔR2* and ΔR2 on the one hand, and LHL15 and HH15 on the other (P<0.05). There were moderate correlations between any combination of increase rates of LSR and LMR on the one hand, and LHL15 and HH15 on the other (P<0.05-0.001)., Conclusion: Pre R2*, ΔR2*, ΔR2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To elucidate the correlation between hypervascular hepatocellular carcinoma (HCC) enhancement patterns on dynamic MR imaging and histological findings., Materials and Methods: Surgically proven 46 hypervascular HCCs of forty-one patients were enrolled. For each HCC, the signal intensity in the portal phase (SIPP) was evaluated. In this study, high, iso-, or low intensity in the portal phase was hypothesized as late, moderate, or early washout pattern, respectively. The SIPP of each HCC was correlated to histological grade and architectural subtypes that represent degrees of trabecular structure. For the trabecular HCCs, the thickness of tumor plate was also correlated for indirect estimation of tumor sinusoid., Results: There was a significant correlation between the SIPP vs. histological grade and also vs. architectural subtypes, namely the degree of trabecular structure. Washout of hypervascular HCC occurred earlier as the histological grade advanced and the histological architecture got closer to pure trabecular HCC. For the trabecular HCCs, the thickness of tumor plate correlated significantly with SIPP or histological grade. Hypervascular HCCs with thicker tumor plates showed worse histological grade and earlier washout pattern., Conclusions: Histological grade of hypervascular HCC may be predicted using SIPP. The thickness of tumor plate, resultantly the size of sinusoid between tumor plates, can account for the relationship between washout pattern and histological grade in the trabecular HCCs., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: The aim of this study was to reveal the relationship between intratumoral uptake of gadoliniumethoxylbenzyldiethylenetriaminepentaacetic acid (Gd-EOB-DTPA) of hepatocellular carcinoma (HCC) in the hepatobiliary phase and pathological features., Materials and Methods: Sixty HCC nodules were confirmed at pathology in 56 patients who had undergone dynamic MRI. T1-weighted 3D gradient echo sequences before and 20 min (hepatobiliary phase) after the injection of Gd-EOB-DTPA were performed. Uptake of Gd-EOB-DTPA was defined as an increase in signal intensity in the hepatobiliary phase compared with the precontrast scan. All surgical specimens were fixed with formalin and then digitally photographed. The relationship between Gd-EOB-DTPA uptake and histological findings, including a macroscopic greenish area, was examined., Results: MR images showed uptake of Gd-EOB-DTPA in twenty-two nodules. Histological findings indicated twenty-six nodules contained a greenish area. There is a significant correlation between HCC showing Gd-EOB-DTPA uptake and the presence of a greenish area (p<0.001). On a nodule-by-nodule basis, more than two-thirds of the area of Gd-EOB DTPA uptake coincides with the greenish part in only 12 of 22 lesions (54.5%). More than two-thirds of the greenish area coincided with that of Gd-EOB-DTPA uptake in only 10 of 26 cases (38.5%)., Conclusion: The area of Gd-EOB-DTPA uptake does not always match the greenish part, but HCC with uptake of Gd-EOB-DTPA significantly correlated with green HCC., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To evaluate the characteristics of hepatocellular carcinomas (HCCs) with marginal superparamagnetic iron oxide (SPIO) uptake on T2*-weighted MRI., Materials and Methods: The study group consisted of 73 patients with 83 surgically resected HCCs. Preoperative SPIO-enhanced MRI studies were retrospectively reviewed. Marginal SPIO uptake was considered positive if a rim-like or band-like low intensity area was present on SPIO-enhanced T2*-weighted images. The prevalence of marginal SPIO uptake was evaluated. Pathological specimens with hematoxylin and eosin staining and immunohistochemical staining of CD68 were reviewed in HCCs with marginal SPIO uptake and 33 HCCs without marginal SPIO uptake (control group)., Results: Ten of 83 (12%) HCCs showed marginal SPIO uptake. All HCCs were hypervascular, and only one nodule showed a nodule-in-nodule appearance on imaging findings. The pathology specimens suggested possible causes of marginal SPIO uptake, including marginal macrophage infiltration in moderately or poorly differentiated HCC (n=4), residual normal hepatic tissue at the marginal area of confluent multinodular or single nodular with extranodular growth type HCC (n=3), and a well-differentiated HCC component in nodule-in-nodule type HCC (n=3). Marginal macrophage infiltration was not seen in the control group., Conclusion: SPIO-enhanced MRI may be able to demonstrate marginal macrophage infiltration in HCC., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Objective: To investigate whether the histological grade of hepatocellular carcinoma (HCC) can be predicted using the apparent diffusion coefficient (ADC)., Materials and Methods: This retrospective study group consisted of 80 patients with 85 surgically resected HCCs who underwent preoperative MRI exams including diffusion-weighted imaging. The tumors were histologically classified into five groups as follows: five well (w-), 17 well to moderately (wm-), 37 moderately (m-), 16 moderately to poorly (mp-), and 10 poorly (p-) differentiated HCCs. For ADC measurement of each HCC, the largest possible region of interest was placed on the solid region on the ADC map where ADC was considered to be the lowest. The average ADCs of the five histological grades were compared using Spearman's rank correlation test and Student's t-test, and the diagnostic performance of ADC for mp- and p-HCCs was also evaluated using a receiver operating characteristic-based positive test., Results: The average ADC of p-HCC (0.76±0.10×10(-3) mm2/s) was significantly lower than those of the other four histological grades. The average ADC of mp-HCCs (0.99±0.20×10(-3) mm2/s) was significantly lower than those of w-, wm- and m-HCCs. The sensitivity, specificity, PPV, NPV, and accuracy, when an ADC of 0.972 or lower was considered an indicator of mp- and p-HCCs, were 73.1%, 72.9%, 54.3%, 86.0% and 72.9%, respectively., Conclusion: ADCs of mp- and p-HCCs were lower than those of w-, wm- and m-HCCs. ADC can contribute to radiological diagnosis of poorly differentiated components in HCCs., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

OBJECTIVE: To evaluate the prevalence of circumportal pancreas (CP) and any coexisting anomaly. In addition, three cases of surgically confirmed CP are presented. METHODS: The study group consisted of 317 consecutive potential liver transplant donor candidates who had undergone thin-section MDCT studies for the evaluation of vascular anatomy. MDCT images were retrospectively reviewed to assess the presence or absence of CP. If CP was present, the transverse diameter of the aberrant pancreatic tissue was measured on axial images, and the course of the main pancreatic duct (MPD) was classified into ante-portal (normal) or retro-portal. In addition, the prevalence of variant hepatic arterial anatomy was compared between cases with and without CP. RESULTS: Eight of 317 liver transplant donor candidates (2.5%) were found to have CP at CT. The transverse diameter of the aberrant pancreatic tissue ranged from 5 to 18 mm (mean ± SD: 10 ± 4 mm). One of eight (12.5%) showed the MPD to be retro-portal. A variant hepatic artery was noted in two of the of eight (25%) patients, which was similar to the finding for those without CP [72 out of 309 (23%)]. CONCLUSION: The prevalence of circumportal pancreas was 2.5%.

Purpose: The aim of the present study was to evaluate the performance of multidetector-row CT (MDCT) and magnetic resonance imaging (MRI) in diagnosing hepatocellular carcinoma (HCC) preoperatively in living related liver transplantation (LRLT) recipients with liver cirrhosis and HCC., Materials and Methods: A total of 25 LRLT recipients with 89 pathologically proved HCCs underwent dynamic 4-row MDCT (5 mm collimation) and MRI within 1 month before LRLT. The images were reviewed for the diagnosis of HCC on a tumor-by-tumor basis by three observers independently and randomly using explanted specimens as the gold standard. The diagnostic accuracy of these techniques in the detection of HCC was assessed with alternative free response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated., Results: The average values of the area under the ROC curve (Az) of MRI images were higher than those obtained with MDCT; however, no significant difference was observed (P > 0.05). The overall sensitivity of HCC with MRI was higher than that with MDCT, especially in the case of HCCs <20 mm., Conclusion: A better diagnostic performance regarding HCCs in LRLT recipients was achieved with MRI than with MDCT, although no significant difference was observed.

Objective: To investigate the relation between safety margins (SMs) and treatment efficacy for hepatocellular carcinoma (HCC) by transcatheter arterial chemoembolization (TACE) using 3-dimensional fusion images of computed tomographic (CT) hepatic arteriography and unenhanced CT., Methods: Fifty-three patients with HCC who underwent subsegmental/segmental TACE were followed up. Lipiodol accumulation patterns within the lesion were classified as determined by unenhanced CT immediately after TACE. Lipiodol accumulation patterns around the lesion were classified as determined by 3-dimensional fusion images with special reference to the SMs, which were compared with the local recurrence (LR) rates., Results: Local recurrence was detected in 29 patients (55%) during the follow-up period. When an SM less than 3 mm was defined as insufficient, the LR rates in groups with and without sufficient SMs were 33% (9/25) and 71% (20/28), respectively (P = 0.0136). In 38 nodules with complete Lipiodol accumulation, 10 (63%) of 16 nodules with LR showed the narrow SM (<3 mm), whereas 5 (23%) of 22 nodules without LR showed the narrow SM (P = 0.1341). Multivariate analyses showed that complete Lipiodol accumulation seemed to be an independent prognostic factor (P = 0.0288)., Conclusions: 3-Dimensional fusion image was suggested to be valuable for the early detection of viable components within the HCC with insufficient SMs after TACE.

Purpose: The aim of this study was to elucidate computed tomography hepatic arteriography (CTHA) and CT arterial portography (CTAP) findings characteristic of hepatocellular carcinoma (HCC) with large hepatic venous invasion (HVI) and then to examine whether the presence of minute HVI can be diagnosed based on each finding., Materials and Methods: Combined CTHA and CTAP of 106 HCCs were examined. Two radiologists analyzed the radiological findings of five nodules with large HVI (group vv2). The remaining 101 nodules were classified into two groups: group vv1, positive minute HVI; group vv0, negative HVI. They examined whether each finding observed in group vv2 could be detected in groups vv1 and vv0., Results: Analysis of group vv2 identified (a) tumor thrombus, (b) early inflow of the contrast into the hepatic vein proximal to the invaded site, and (c) partially decreased portal venous flow in the peripheral parenchyma subject to the involved hepatic vein. Findings (b) and (c) were observed in 16% of group vv1. A significant difference in frequency of finding (c) was obtained between groups vv1 and vv0. The positive and negative predictive values of finding (c) were 66.7% and 77.9%, respectively., Conclusion: Findings (b) and (c), especially the latter, may partly contribute to the radiological diagnosis of minute HVI.

Aim: Cholangiolocellular carcinoma (CoCC) is currently considered to originate from hepatic progenitor cells. The purpose of this study was to evaluate the imaging features of cholangiolocellular carcinoma of the liver., Materials and Methods: Five cases of surgically resected cases of CoCC from 4 institutions were retrospectively evaluated. All of the five patients underwent contrast-enhanced dynamic CT. MRI and angio-CT including CT during arterioportography (CTAP) and CT during hepatic arteriography were performed in 3 and 2 patients, respectively. Histological evaluation was also performed and was correlated with radiographic findings., Results: On dynamic CT or MRI, the lesions presented hypervascular tumors with delayed washout in 2 cases and in the other 3 cases, the lesions showed peripheral enhancement with concentric delayed filling. On CTAP, the continued existence of portal veins or tiny spots of portal flow was identified in the tumors. Fibrous capsule or tumor necrosis was not observed., Conclusion: CoCC tumors have the dual imaging characteristics of hepatocellular carcinoma and cholangiocarcinoma. The absence of a fibrous capsule, the absence of tumor necrosis, peripheral location within the liver, and the presence of portal venous penetration within the tumor also appear to be characteristic features., (Copyright 2009 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To clarify if the portal venous phase is helpful for the differential diagnosis of groove pancreatic carcinomas and groove pancreatitis., Materials and Methods: MDCT and MRI of groove pancreatic carcinomas (n=7) and groove pancreatitis (n=15) were retrospectively reviewed by two radiologists independently. The signal intensity on T2-weighted images was subjectively assessed. The presence or absence of common bile duct (CBD) and main pancreatic duct (MPD) strictures, calcifications, and cystic lesions was evaluated. Additionally, the appearance of groove pancreatic carcinoma and that of groove pancreatitis in the portal venous phase on dynamic MDCT and MRI were compared., Results: There were no significant differences in the signal intensity on T2-weighted images and in the presence or absence of CBD and MPD strictures, calcifications, and cystic lesions between groove pancreatic carcinomas and groove pancreatitis. However, patchy focal enhancement in the portal venous phase was more commonly observed in groove pancreatitis than groove pancreatic carcinoma (Reviewers 1 and 2: 14/15 [93.3%] vs. 1/7 [14.3%], P<0.0001). In addition, peripheral enhancement was only seen in groove pancreatic carcinomas (Reviewer 1: 4/7 [57.1%] vs. 0/15 [0%], P<0.005, and Reviewer 2: 3/7 [42.9%] vs. 0/15 [0%], P<0.05)., Conclusion: The portal venous phase may be helpful for the differential diagnosis of groove pancreatic carcinomas and groove pancreatitis., (Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To clarify whether there are differences in MRI findings between pancreatic lymphomas and autoimmune pancreatitis (AIP)., Materials and Methods: MRI of 8 patients with pancreatic lymphomas and 21 patients with AIP were retrospectively reviewed. For multifocal pancreatic lymphomas (n=2) and AIP (n=4), the largest 2 lesions were evaluated. Ten pancreatic lymphomas and 25 AIP were compared on three bases: the signal intensity on T2-weighted images, internal homogeneity, and presence or absence of capsule-like rim. In 8 lymphomas and 19 AIP, the enhancement pattern on dynamic MRI was compared, as well., Results: On T2-weighted images, pancreatic lymphomas comprised 5, 5 and 4 lesions with low (iso), slightly high, and moderately high intensity, respectively, while the numbers for AIP were 14, 10, and 1 (P<0.01). Nine of 10 (90%) lymphomas appeared homogenous, and 11 of 25 (44%) AIP were homogenous (P<0.05). A capsule-like rim was present in 9 of 25 (36%) AIP, but was not seen in lymphomas (P<0.05). On dynamic MRI, 18 of 19 (94.7%) AIP showed persistent (n=5) or delayed enhancement (n=13), and 6 of 8 (75%) lymphomas showed low intensity without delayed enhancement (P<0.001)., Conclusion: MRI findings for pancreatic lymphomas and AIP were significantly different, which may be helpful for the differential diagnosis of these two diseases., (Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To investigate the validity of the fetal right lung-to-liver signal intensity ratio (LLSIR) for prediction of postnatal outcomes in left-sided congenital diaphragmatic hernia (CDH) MATERIALS AND METHODS: The study included 14 pregnant women who underwent MR exams for evaluation of fetal left-sided CDH. The fetuses were divided into two groups: Group A (n = 9), alive, and Group B (n = 5), dead. On the basis of the half-Fourier acquisition single-shot turbo spin-echo sequence, LLSIR and the right fetal lung volume (FLV) was calculated. In the control group, a regression analysis was performed to associate LLSIR and right FLV with gestational age. The relative LLSIR and right FLV (the observed/expected LLSIR and right FLV) were compared between Groups A and B., Results: The mean relative LLSIR, as well as the mean relative right FLV, of Group A was significantly higher than that of Group B (p = 0.035). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the relative LLSIR and the relative right FLV, when the cutoff point was defined as 0.646 and 0.420, were the same and were 88.9%, 80.0%, 88.9%, 80.0%, and 85.7%, respectively., Conclusion: The postnatal outcomes in left-sided CDH may be predicted using the LLSIR., ((c) 2009 Wiley-Liss, Inc.)

Purpose: To evaluate the interval change of perivascular soft tissue (PVST) around the common hepatic and proximal superior mesenteric arteries arising after pancreaticoduodenectomy (PD) and to compare the difference between post operative change (benign PVST) and recurrence (malignant PVST)., Materials and Methods: Serial multidetector CT (MDCT) studies in 44 patients who underwent PD for periampullary carcinomas were retrospectively reviewed (Group A). The incidence and interval change of PVST were evaluated and compared to control group (Group B, 21 patients with PD for benign diseases)., Results: PVST was seen in all the 44 patients in Group A, and it was noted in 12 of 21 (57.1%) patients in Group B. Thirteen of 44 (29.5%) patients showed interval enlargement of PVST (malignant PVST), and 12 of 13 developed within 2 years after PD. There was higher incidence of malignant PVST in patients with lymph node metastasis (p < 0.01) and those with pancreas head carcinoma (p < 0.05)., Conclusion: PVST is common after PD regardless of whether patients had malignant or benign diseases. PVST should be monitored for at least 2 years to distinguish recurrence from post operative change. Patients with lymph node metastasis and pancreas head carcinoma had a higher incidence of malignant PVST.