Search

This study aimed to elucidate the relationship between gadoxetic acid–enhanced magnetic resonance imaging (MRI) features—enhancing capsule, corona enhancement or hypointense rim—observed in hepatocellular carcinomas (HCCs). Of the HCCs surgically confirmed during a 5-year period (2013–2017), ≤ 3-cm lesions (n = 83) in 78 patients were evaluated. Presence of corona enhancement and enhancing capsule on multiphasic dynamic imaging and presence of hypointense rim on hepatobiliary phase imaging were determined retrospectively by two independent observers. The relationship among the three imaging features was statistically analysed and correlated with the presence of histologic fibrous capsules, tumour differentiation and gross morphologic type. There was substantial overall interobserver agreement in determining the presence of the three imaging features. Sixty (72.3%) lesions had histologic fibrous capsule positively correlated with all three imaging features (p < 0.05). Corona enhancement was the most common (66.3%) feature followed by enhancing capsule (61.4%) and hypointense rim (33.7%), and the correspondence rate of enhancing capsule to corona enhancement was 68.6% (p = 0.004). Corona enhancement was more frequently observed in moderately differentiated HCCs than other lesions (p = 0.012) and not dependent (p = 0.465) on the tumour size, while enhancing capsule was significantly dependent on tumour size, as indicated by univariate (p < 0.001) and multivariate analyses (odds ratio, 4.241; p = 0.002). Among the capsular features, corona enhancement might closely relate to enhancing capsule in HCCs. Corona enhancement was not dependent on tumour size and had the highest incidence of appearance on gadoxetic acid–enhanced multiphasic dynamic MRI. • Enhancing capsule has a limited role in the LI-RADS categorisation during gadoxetic acid–enhanced MRI. • Appearance of corona enhancement is closely related to enhancing capsule and is not dependent on size of HCCs. • Corona enhancement can substitute enhancing capsule in the diagnosis of HCCs during multiple arterial and portal venous phase gadoxetic acid–enhanced MRI.

OBJECTIVE. The purpose of this study is to validate the use of subtraction images derived from gadoxetic acid-enhanced MRI for observation of washout and enhancing capsule in the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS. For 120 histologically verified HCCs in 115 high-risk patients, the presence of washout and enhancing capsule in the portal venous phase (PVP) on conventional MR images with and without corresponding subtraction images was determined by two independent observers. The incremental value of subtraction imaging in upgrading the categories outlined in the Liver Imaging Reporting and Data System (LI-RADS) version 2018 for the diagnosis of HCC was analyzed for different subgroups of patients classified on the basis of lesion size (< 10 mm, 10-19 mm, ≥ 20 mm), unenhanced T1-weighted signal intensity, and arterial phase hyperenhancement (APHE) of the lesions. RESULTS. When conventional PVP images were compared with the combination of conventional and subtraction PVP images, only T1-weighted isointensity or hyperintensity significantly increased the detection of washout (eight vs 15 of 18 lesions; p = 0.0233). Detection of enhancing capsule was significantly increased (p < 0.05) regardless of various factors, except for a lesion size of less than 2 cm (five vs nine of 36 lesions; p = 0.1336). Two lesions (one LI-RADS category 3 lesion and one LI-RADS category 4 lesion) with APHE were upgraded to category 5 on the basis of a review of PVP subtraction images. CONCLUSION. PVP subtraction imaging during gadoxetic acid-enhanced MRI can upgrade LI-RADS categories for the diagnosis of HCC because of its superior ability in depicting enhancing capsule and the incremental benefit of showing washout.

Background: This study evaluated the ultrasonographic and clinical findings of two groups with rhabdomyolysis, who showed abnormal or normal ultrasonographic findings of kidneys. Methods: Two groups (n = 78) of abnormal (A) and normal (B) renal ultrasonographic findings were included. Multiple laboratory findings were assessed within 2 days before or after ultrasonography. Student's t-test or Mann–Whitney U-test was used for statistical analysis. Results: The variable causes of rhabdomyolysis were intense exercise, burn, operation, shivering, and drug intoxication, etc. Group A (n = 26; M:F = 19:7) showed enlarged both kidneys, increased parenchymal thickness, and increased (n = 23, 88.5%) or decreased (n = 3, 11.5%) cortical echogenicity. Group A also showed elevated blood urea nitrogen (BUN), creatinine, potassium, and prolonged activated partial thromboplastin time (aPTT), compared with those in Group B (n = 52; M:F = 36:16), and these results were statistically significant (P < 0.01). The myoglobin in serum and urine, creatine kinase, prothrombin time, dark urine, and microscopic hematuria were not statistically different between the two groups. Conclusion: Patients with elevated BUN, creatinine, potassium, and prolonged aPTT showed the ultrasonographic findings of acute kidney injury, but other parameters were not statistically different between the two groups.

OBJECTIVE The aim of the study was to evaluate the performance of texture analysis for discriminating the histopathological grade of hepatocellular carcinoma (HCC) on magnetic resonance imaging. METHODS Preoperative magnetic resonance imaging data from 101 patients with HCC, including T2-weighted imaging, arterial phase, and apparent diffusion coefficient mapping, were analyzed using texture analysis software (TexRAD). Differences among the histological groups were analyzed using the Mann-Whitney U test. The performance of texture features was evaluated using receiver operating characteristic analysis. RESULTS Entropy was the most significantly relevant texture feature for distinguishing each histological grade group of HCC (P < 0.05). In ROC analysis, entropy with spatial scale filter 3 (area under curve the receiver operating characteristic curve [AUC], 0.778), mean with coarse filter (spatial scale filter 5; AUC, 0.670), and skewness without filtration (AUC, 0.760) had the highest AUC value on T2-weighted imaging, arterial phase, and apparent diffusion coefficient maps, respectively. CONCLUSIONS Magnetic resonance imaging texture analysis demonstrated potential for predicting the histopathological grade of HCCs.

This study aims to evaluate the performance of a radiomic signature-based model for predicting recurrence-free survival (RFS) of locally advanced gastric cancer (LAGC) using preoperative contrast-enhanced CT. This retrospective study included a training cohort (349 patients) and an external validation cohort (61 patients) who underwent curative resection for LAGC in 2010 without neoadjuvant therapies. Available preoperative clinical factors, including conventional CT staging and endoscopic data, and 438 radiomic features from the preoperative CT were obtained. To predict RFS, a radiomic model was developed using penalized Cox regression with the least absolute shrinkage and selection operator with ten-fold cross-validation. Internal and external validations were performed using a bootstrapping method. With the final 410 patients (58.2 ± 13.0 years-old; 268 female), the radiomic model consisted of seven selected features. In both of the internal and the external validation, the integrated area under the receiver operating characteristic curve values of both the radiomic model (0.714, P P = 0.010 [external validation]) and the merged model (0.719, P P = 0.014) were significantly higher than those of the clinical model (0.616; 0.594). The radiomics-based model on preoperative CT images may improve RFS prediction and high-risk stratification in the preoperative setting of LAGC.

This study seeks to illuminate the need to protect women’s rights by tracing legal changes and the unconstitutional decisions pertaining to the adultery statutes in Korea. Sexual freedom trumps sex...

Objective: To investigate the feasibility of using the attenuation-based automatic tube potential selection (ATPS) algorithm for cerebral computed tomography angiography (CTA) and to assess radiation dose, vascular attenuation, and image quality compared to a conventional fixed 120-kVp protocol. Materials and Methods: Among 36 volunteers for cerebral CTA, a total of 18 were scanned with fixed 120 kVp and 140 effective mAs using automatic tube current modulation. The other 18 were scanned with an ATPS algorithm. Radiation doses, attenuation, contrast-to-noise ratio (CNR) of the cerebral arteries, subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, venous contamination, image noise, and overall image quality were compared between the groups. Results: The volume CT dose index and effective dose of the ATPS group were lower than those of the fixed 120-kVp group. The ATPS group had significantly higher arterial attenuation and no significant difference in CNR, compared with the fixed 120- kVp. The ATPS group had higher subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, and overall image quality. Conclusion: The ATPS algorithm for the cerebral CTA reduced radiation dose by 43% while maintaining image quality and improved the attenuation of cerebral arteries by selecting lower tube potential.

To evaluate the characteristic multidetector CT findings of peritoneal tuberculous (TB) cold abscesses. The morphological characteristics of 48 peritoneal TB cold abscesses in 29 patients (male:female = 13:16; age range 16–75 years) were retrospectively evaluated. TB infection was histologically proven by acid fast bacilli (AFB) smear or culture, TB-polymerase chain reaction (PCR), or histopathological specimen diagnosis. Seventeen abscesses (35.4%) were present in the right perihepatic space, 10 (20.8%) in the left subphrenic space, 6 (12.5%) in the right subphrenic space, 4 (8.3%) in the pelvic cavity, 3 (6.3%) in the left perihepatic space, 3 (6.3%) in the right lower quadrant, and so on. The abscess contents ranged from 10.4 to 61.4 Hounsfield units. Internal septa (64.6%), central necrotic lymphadenopathy (55.2%), and TB coinfections in other organs (65.5%) were observed. TB infection was histopathologically confirmed from the surgical specimens in 17 patients and other 4 patients revealed the positive TB-PCR results from the peritoneal fluid. Ten patients (34.5%) had a recent history of TB peritonitis with ascites. Peritoneal TB cold abscesses were commonly found in the right perihepatic and subphrenic spaces and revealed higher density of internal content, frequent internal septa, central necrotic lymphadenopathy, and high TB coinfections in other organs.

Japanese adult criminal statistics of the execution of the jurisdiction are highly changeable or repeatedly fluctuate according to the characteristics of the regime. However, juvenile criminal statistics have been relatively stable because juvenile justice system is different from that of adult. The reason is that the criminal justice agencies, (i.e. public prosecutors and police officers), media reports, and victims’ activities directly impact on the adult criminal statistics. Furthermore public prosecutors have the right of prosecution and also have a broad discretion in the criminal justice system. On the contrary, the public prosecutors have no power to screen cases for prosecution in the juvenile justice system; that power resides with the family court judges. The family court judges are relatively more independent by the characteristics of the regime than the prosecutors. Juvenile justice is not a reaction against political issues, and juvenile criminal statistics are not a product of the regime’s characteristics. This article suggests new ideologies about juvenile justice policies to protect individual juveniles and to prevent crimes.

To investigate the effect of peri-ampullary duodenal diverticula (PAD) on extrahepatic bile duct (EHBD) dilatation before and after cholecystectomy.During a 5-year period, a total of 860 consecutive patients with prior cholecystectomy were examined using abdominal computed tomography (CT). After exclusion of those with other obstructive EHBD lesions, 61 patients with PAD were recruited for evaluation of EHBD dilatation before and after cholecystectomy and were compared with a randomly sampled control group (n=113) without PAD. EHBD diameter was measured on coronal reconstruction CT using electronic callipers on the picture archiving and communication system monitors by two reviewers in consensus.There was no significant difference in EHBD diameter between PAD and non-PAD groups (8.2±2.8 versus 7.8±2.3 mm; p=0.276) before cholecystectomy. Compared with preoperative diameter, EHBD was significantly dilated after cholecystectomy (7.9±2.5 versus 9.8±3.4 mm, p0.001), regardless of the presence of PAD; the degree of change was more prominent in the PAD group than in the non-PAD group (3.3±2.4 versus 1.1±1.6 mm; p0.001) after surgery. The size of PAD did not affect the degree of EHBD dilatation after cholecystectomy (p=0.522). In the non-PAD group, the degree of EHBD dilatation was positively correlated with the follow-up interval after cholecystectomy (r=0.298; p=0.002), while the PAD group showed no significant correlation (r=-0.036; p=0.797). In patients with ≥2 mm postoperative EHBD dilatation, PAD incidence was higher than that in other patients (odds ratio, 8.739; p0.001).Regardless of their size or postoperative follow-up duration, PAD induce marked post-cholecystectomy biliary dilatation.

This paper elucidates the development of a deep learning&ndash, based driver assistant that can prevent driving accidents arising from drowsiness. As a precursor to this assistant, the relationship between the sensation of sleep depravity among drivers during long journeys and CO2 concentrations in vehicles is established. Multimodal signals are collected by the assistant using five sensors that measure the levels of CO, CO2, and particulate matter (PM), as well as the temperature and humidity. These signals are then transmitted to a server via the Internet of Things, and a deep neural network utilizes this information to analyze the air quality in the vehicle. The deep network employs long short-term memory (LSTM), skip-generative adversarial network (GAN), and variational auto-encoder (VAE) models to build an air quality anomaly detection model. The deep learning models gather data via LSTM, while the semi-supervised deep learning models collect data via GANs and VAEs. The purpose of this assistant is to provide vehicle air quality information, such as PM alerts and sleep-deprived driving alerts, to drivers in real time and thereby prevent accidents.

Objectives Apparent diffusion coefficient (ADC) has been suggested to reflect the tumor grades of hepatocellular carcinomas (HCCs); i.e., it can be used as a biomarker to predict the patients’ prognosis. To verify its feasibility as a biomarker, the present study sought to determine how the ADC values of HCC are affected by a tumor’s histopathologic grade and arterial vascularity. Materials and methods From 131 consecutive patients, 141 surgically resected HCCs (16 well-differentiated [wd-HCCs], 83 moderately-differentiated [md-HCCs], and 42 poorly-differentiated HCCs [pd-HCCs]) were subjected to a comparison of the tumors’ arterial vascularity (non-, slightly-, or markedly-hypervascular) determined on dynamic magnetic resonance imaging (MRI) and the ADC was measured retrospectively. Results The pd-HCCs (1.05±0.16 × 10−3 mm2/s) had a significantly lower ADC than md-HCCs (1.16±0.21 × 10−3 mm2/s; p = 0.010), but there was no significant difference compared to wd-HCCs (1.11±0.18 × 10−3 mm2/s; p = 0.968). The mean ADC was significantly higher in markedly hypervascular lesions (1.20±0.20 × 10−3 mm2/s) than in nonhypervascular lesions (0.95±0.14 × 10−3mm2/s; p

Our purpose was to assess the endoscopic ultrasonography (EUS) features of serous cystic neoplasms (SCNs) of the pancreas in determining the surgical removal compared with computed tomography (CT) and magnetic resonance imaging (MRI) features. For 33 consecutive patients with 34 surgically confirmed SCNs over the past 11 years, preoperative EUS features were compared with those of CT and MRI (CTMRI). Besides the lesion size and location, a retrospective analysis of the various imaging features was performed by 2 observers to understand the characteristics that determine the need for surgical intervention in terms of multiplicity of locules, calcification, mural thickening, mural nodules, ductal communication, and main pancreatic duct dilatation in addition to the gross morphologic type: microcystic, macrocystic (1 cm), mixed, or solid. The most common gross morphologic type was mixed lesions, which consisted of microcystic and macrocystic components (15/34; 44%), followed by microcystic (38%), macrocystic (15%), and solid (3%) lesions. A minority (5/34; 18%) of the lesions showed main pancreatic duct dilatation (upstream, n = 3; downstream, n = 0; diffuse, n = 2). Mural nodules or solid components were more frequently noted in EUS (67%) than in CTMRI (25%; P = 0.001), whereas other findings showed no remarkable difference between EUS and CTMRI (P0.05). In determining the surgical treatment of multiloculated cystic lesions, interpretation of EUS features for the presence of solid component or mural nodules should be more carefully determined, especially in the patients with suggestive features of SCN on CT or MRI to avoid unnecessary surgery.

Emerging concerns regarding the hazard from medical radiation including CT examinations has been suggested. The purpose of this study was to observe the longitudinal changes of CT radiation doses of various CT protocols and to estimate the long-term efforts of supervising radiologists to reduce medical radiation. Radiation dose data from 11 representative CT protocols were collected from 12 hospitals. Attending radiologists had collected CT radiation dose data in two time points, 2007 and 2010. They collected the volume CT dose index (CTDIvol) of each phase, number of phases, dose length product (DLP) of each phase, and types of scanned CT machines. From the collected data, total DLP and effective dose (ED) were calculated. CTDIvol, total DLP, and ED of 2007 and 2010 were compared according to CT protocols, CT machine type, and hospital. During the three years, CTDIvol had significantly decreased, except for dynamic CT of the liver. Total DLP and ED were significantly decreased in all 11 protocols. The decrement was more evident in newer CT scanners. However, there was substantial variability of changes of ED during the three years according to hospitals. Although there was variability according to protocols, machines, and hospital, CT radiation doses were decreased during the 3 years. This study showed the effects of decreased CT radiation dose by efforts of radiologists and medical society., Graphical Abstract

To investigate the very long-term ( 5 years) follow-up changes of hepatic cavernous hemangiomas and to evaluate possible determinant factors for the changes.Among 1115 consecutive patients suspected of having hepatic hemangiomas based on imaging features, 101 patients with comparable computed tomography or magnetic resonance imaging data during a 5-year follow-up interval in the Picture Archiving and Communication System were analyzed. Two radiologists independently determined the largest dimension of each lesion on axial images. In addition to background liver fibrosis or steatosis on imaging, histories of use of chemotherapeutic agents were checked from the patients' records. The final size change of the hemangioma was categorized into three groups compared with the initial diameter (increased, 120%; no change, 80-120%; decreased, 80%).Among the 101 hemangiomas, 32 lesions (31.7%) were enlarged and 21 lesions (20.8%) were shrunken during intervals of 60-157 (median, 81) months. Younger patients showed a higher prevalence of lesion enlargement (mean age: enlarged, 47.3 years; no change, 52.8 years; shrunken, 57.1 years; p = 0.003). In 15 patients with cirrhosis, the lesions (shrunken, n = 7; enlarged, n = 1) showed a higher tendency of size decrease (p = 0.009), whereas other factors did not show statistical significance (p 0.05). Only a minor proportion (1%, n = 1) of the lesions showed size fluctuation during follow-up.During the long-term (5-13 years) follow-up, about 50% of the hepatic hemangiomas were enlarged or shrunken to 20% of the initial diameter. Aside from the cirrhosis and aging factors, the size changes seemed sporadic.

The purpose of this study was to find the optimal allocation ratio of contrast medium (CM) in split-bolus CT urography (CTU) and to investigate the effect of increased imaging delays for synchronous nephrographic-excretory phase imaging.One hundred ninety-two patients were randomly assigned to one of three protocols with different allocation ratios of CM: group A, 30% of CM at first bolus and 70% of CM at second bolus; group B, 70% and 30%; or group C, 50% and 50%. Saline (250 mL) was administered after the first CM bolus. Patients were subdivided by different imaging delay times (8, 10, 12, and 14 minutes). The attenuation values of the renal cortex and medulla were measured, and the opacification and maximal caliber of each segment of the ureter were evaluated.Renal cortical enhancement was significantly higher in group A (mean ± SD, 145.9 ± 17.5 HU) than group B (120.6 ± 106.3 HU). No significant difference in renal parenchymal enhancement was found with increased imaging delay times. The opacification and maximal caliber of each ureter segment showed no significant difference with different allocation ratios of CM or increased imaging delay times.A split-bolus CTU protocol with a larger CM volume administered at the second injection and an 8-minute imaging delay was the optimal protocol with regard to opacification of the ureter, renal parenchymal enhancement, and shorter examination time.

Purpose With review of anatomy and vascular supplies in male genitalia, we will present the ultrasonographic findings of various cases involving testis, epididymis and penis. Materials and Methods All of eleven cases were confirmed either pathologically or clinically. We present 3 cases of scrotal neoplasms (immature teratoma, rapid growing and large seminoma, mixed germ cell tumor), 2 cases of infectious diseases (tuberculous epididymo-orchitis, mumps epididymo-orchitis, 3 cases of other scrotal diseases (testicular torsion, testicular rupture, epididymal rupture), and 3 cases of penile diseases (penile fracture, paraffinoma, leiomyosarcoma). Results Eleven cases of various diseases involving the male genitalia showed the variable ultrasonographic findings on grey scale and color Doppler ultrasonography. Clinical history is helpful in the diagnosis of some cases, such as mumps epididymitis, post-traumatic rupture of testis or epididymis, penile fracture or penile paraffinoma. Conclusion We have to know the clinical history and specific ultrasonographic findings of various diseases of male genitalia for the exact diagnosis and differentiation.

OBJECTIVE. The purpose of this article is to discuss the importance of lateral pelvic lymph node metastasis as a predictor of local recurrence and survival in patients with advanced rectal cancer. CONCLUSION. Prediction of lateral pelvic nodal staging on MRI shows high accuracy compared with the other imaging modalities. Diffusion-weighted MRI or 18F-FDG PET/CT may be helpful to assesses lateral pelvic lymph node metastasis.

Objective To investigate the validity of the 100 kVp setting in CT venography (CTV) in the diagnosis of deep vein thrombosis (DVT), and to evaluate the feasibility of reducing the amount of administered iodine in this setting. Materials and methods After receiving the contrast medium (CM) of 2.0 mL/kg, 88 patients underwent CTV of the pelvis and lower extremities by using one of four protocols: Group A, 120 kVp setting and 370 mgI/mL CM; group B, 120 kVp and 300 mgI/mL; group C, 100 kVp and 370 mgI/mL; group D, 100 kVp and 300 mgI/mL. The groups were evaluated for venous attenuation, vein-to-muscle contrast-to-noise ratio (CNR(VEIN)), DVT-to-vein contrast-to-noise ratio (CNR(DVT)), and subjective degree of venous enhancement and image quality. Results Venous attenuation and CNR(VEIN) were significantly higher in group C (144.3 Hounsfield unit [HU] and 11.9), but there was no significant difference between group A (118.0 HU and 8.2) and D (122.4 HU and 7.9). The attenuation value of DVT was not significantly different among the four groups, and group C had a higher absolute CNR(DVT) than the other groups. The overall diagnostic image quality and venous enhancement were significantly higher in group C, but there was no difference between groups A and D. Conclusion The 100 kVp setting in CTV substantially help improve venous enhancement and CNR(VEIN). Furthermore, it enables to reduce the amount of administered iodine while maintaining venous attenuation, as compared with the 120 kVp setting.

Objective To validate preoperative dynamic CT and fecal elastase-1 level in predicting the development of pancreatic fistulae after pancreatoduodenectomy. Materials and methods For 146 consecutive patients, CT attenuation values of the nontumorous pancreatic parenchyma were retrospectively measured on precontrast, arterial and equilibrium phase images for calculation of enhancement ratios. CT enhancement ratios and preoperative fecal elastase-1 levels were correlated with the development of pancreatic fistulae using independent t-test, logistic regression models, ROC analysis, Youden method and tree analysis. Results The mean value of enhancement ratio on equilibrium phase was significantly higher (p = 0.001) in the patients without pancreatic fistula (n = 107; 2.26±3.63) than in the patients with pancreatic fistula (n = 39; 1.04±0.51); in the logistic regression analyses, it was significant predictor for the development of pancreatic fistulae (odds ratio = 0.243, p = 0.002). The mean preoperative fecal elastase-1 levels were higher (odds ratio = 1.003, p = 0.034) in the pancreatic fistula patients than other patients, but there were no significant differences in the areas under the curve between the prediction values of CT enhancement ratios and fecal elastase-1 combined and those of CT enhancement ratios alone (P = 0.897, p = 0.917) on ROC curve analysis. Tree analysis revealed that the CT enhancement ratio was more powerful predictor of pancreatic fistula than fecal elastase-1 levels. Conclusion The preoperative CT enhancement ratio of pancreas acquired at equilibrium phase regardless of combination with fecal elastase-1 levels might be a useful predictor of the risk of developing a pancreatic fistula following pancreatoduodenectomy.

Aim To validate the usefulness of diffusion-weighted imaging (DWI) in the differentiation of high-flow haemangiomas showing pseudo-washout appearance on gadoxetic acid-enhanced hepatic MRI from small hypervascular hepatocellular carcinomas (HCCs). Materials and methods DWI (b=50, 800 s/mm2) with apparent diffusion coefficient (ADC) maps for 50 haemangiomas (6.4±2.9 mm) showing intense enhancement on arterial dominant phase imaging and hypointensity on transitional and/or hepatobiliary phase imaging during gadoxetic acid-enhanced MRI were retrospectively analysed and compared with that of 113 hypervascular HCCs (12.8±3.7 mm). In addition to measurement of mean ADC values on DWI and contrast-to-noise ratio (CNR) on corresponding T2-weighted imaging, qualitative analysis of DWI was performed for each lesion by two independent observers using a five-point scale. Results Both of mean ADC value (1.902 versus 0.997×10−3 mm2/s) and mean CNR (119.2 versus 36.9) for haemangioma were significantly larger than for HCC (p Conclusion For high-flow small haemangiomas showing pseudo-washout appearance during gadoxetic acid-enhanced hepatic MRI, high b-factor DWI including an ADC map may provide additional information to enhance the confidence to exclude small hypervascular HCCs.

Objective To prospectively investigate the feasibility of an 80-kilovolt (peak) (kVp) protocol in computed tomographic venography for varicose veins of the lower extremities by comparison with conventional 120-kVp protocol. Methods Attenuation values and signal-to-noise ratio of iodine contrast medium (CM) were determined in a water phantom for 2 tube voltages (80 kVp and 120 kVp). Among 100 patients, 50 patients were scanned with 120 kVp and 150 effective milliampere second (mAs(eff)), and the other 50 patients were scanned with 80 kVp and 390 mAs(eff) after the administration of 1.7-mL/kg CM (370 mg of iodine per milliliter). The 2 groups were compared for venous attenuation, contrast-to-noise ratio, and subjective degree of venous enhancement, image noise, and overall diagnostic image quality. Results In the phantom, the attenuation value and signal-to-noise ratio value for iodine CM at 80 kVp were 63.8% and 33.0% higher, respectively, than those obtained at 120 kVp. The mean attenuation of the measured veins of the lower extremities was 148.3 Hounsfield units (HU) for the 80-kVp protocol and 94.8 HU for the 120-kVp protocol. Contrast-to-noise ratio was also significantly higher with the 80-kVp protocol. The overall diagnostic image quality of the 3-dimensional volume-rendered images was good with both protocols. The subjective score for venous enhancement was higher at the 80-kVp protocol. The mean volume computed tomography dose index of the 80-kVp (5.6 mGy) protocol was 23.3% lower than that of the 120-kVp (7.3 mGy) protocol. Conclusion The use of the 80-kVp protocol improved overall venous attenuation, especially in perforating vein, and provided similarly high diagnostic image quality with a lower radiation dose when compared to the conventional 120-kVp protocol.

Purpose The purpose of the study was to validate diffusion-weighted imaging (DWI) in the assessment of hypervascular hepatocellular carcinoma (HCC) compared with superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) in the cirrhotic liver. Material and Methods Forty-six consecutive patients with 106 hypervascular focal lesions in the cirrhotic liver who underwent DWI using three b factors and gadopentetate dimeglumine-enhanced dynamic MRI followed by SPIO-enhanced MRI were enrolled. Two independent radiologists evaluated two separated image sets (SPIO set, dynamic MRI and SPIO-enhanced T2*-weighted images; DWI set, DWI and dynamic MRI) and assigned confidence levels for diagnosis of HCC using a five-point scale for each lesion. Area under the receiver operating characteristic curve ( A z ) was calculated for each image set. Results The A z value of the DWI set was larger than the SPIO set by both readers (reader 1, 0.936 vs. 0.900, P =.050; reader 2, 0.938 vs. 0.905, P =.110). For the sensitivity (reader 1, 93.1% vs. 86.2%, P =.146; reader 2, 95.4% vs. 88.5%, P =.070) and specificity (reader 1, 89.5% vs. 73.7%, P =.250; reader 2, 79.0% vs. 73.7%, P =1.000) of HCC diagnosis, DWI sets were superior to SPIO sets without statistically significant differences. Conclusion For assessment of hypervascular HCC, DWI in combination with dynamic MRI provides comparable or slightly better information compared with the combination of dynamic and SPIO-enhanced MRI.

The purpose of our study was to compare diffusion-weighted MR imaging (DWI) with conventional dynamic MRI in terms of the assessment of small intrahepatic metastases from hepatocellular carcinoma (HCC).In 24 patients with multifocal, small (≤2 cm) intrahepatic metastatic foci of advanced HCC, a total of 134 lesions (≤1 cm, n=81;1 cm, n=53) were subjected to a comparative analysis of hepatic MRI including static and gadopentetate dimeglumine-enhanced dynamic imaging, and DWI using a single-shot spin-echo echo-planar MRI (b values=50, 400 and 800 s/mm(2)), by two independent reviewers.A larger number of the lesions were detected and diagnosed as intrahepatic metastases on DWI [Reviewer 1, 121 (90%); Reviewer 2, 117 (87%)] than on dynamic imaging [Reviewer 1, 107 (80%); Reviewer 2, 105 (78%)] (P.05). For the 81 smaller lesions (≤1 cm), DWI was able to detect more lesions than dynamic imaging [Reviewer 1, 68 (84%) vs. 56 (69%), P=.008; Reviewer 2, 65 (80%) vs. 55 (68%), P=.031], but there was no statistically significant difference between the two image sets for larger (1 cm) lesions.Due to its higher detection rate of subcentimeter lesions, DWI could be considered complementary to dynamic MRI in the diagnosis of intrahepatic metastases of HCCs.

Aim To compare high-resolution pelvic magnetic resonance imaging (MRI) with positron emission tomography (PET)/computed tomography (CT) for the preoperative assessment of nodal staging in rectal cancer. Materials and methods Thirty patients who had surgery for rectal cancer were retrospectively enrolled during a 6-month period. Each patient underwent high-resolution pelvic MRI and PET/CT preoperatively within the same week. An experienced radiologist predicted nodal staging on MR, and an experienced nuclear medicine physician similarly predicted nodal staging on PET/CT. Their predictions were compared with pathologic staging results, retrospectively. Results The accuracies of nodal status prediction from MR and PET/CT were 83% and 70%, respectively. Magnetic resonance imaging had a sensitivity of 94% and a specificity of 67%, whereas PET/CT had a sensitivity of 61% and a specificity of 83%. A combination of MRI and PET/CT revealed a sensitivity of 94%, a specificity of 83%, and an accuracy of 90%. Conclusion High-resolution pelvic MRI was more accurate than PET/CT for the prediction of regional nodal status. Magnetic resonance imaging had a high sensitivity and PET/CT had a high specificity for N staging in rectal cancer.

Objective: We wanted to identify the geographic differences in hepatic fibrosis and their associations with the atrophyhypertrophy complex in patients with chronic viral hepatitis using the dual-contrast material-enhanced MRI (DC-MRI) with gadopentetate dimeglumine and ferucarbotran. Materials and Methods: Patients with chronic C (n = 22) and B-viral hepatitis (n = 35) were enrolled for determining the subjective grade of fibrosis (the extent and thickness of fibrotic reticulations) in the right lobe (RL), the caudate lobe (CL), the medial segment (MS) and the lateral segment (LS) of the liver, with using a 5-grade scale, on the gradient echo T2*weighted images of DC-MRI. The fibrosis grades of different segments were compared using the Kruskal-Wallis test followed by post-hoc analysis to establish the segment-by-segment differences. The incidences of two pre-established morphologic signs of cirrhosis were also compared with each other between the two groups of patients. Results: There were significant intersegmental differences in fibrosis grades of the C-viral group ( p = 0.005), and the CL showed lower fibrosis grades as compared with the grades of the RL and MS, whereas all lobes were similarly affected in the B-viral group (p = 0.221). The presence of a right posterior hepatic notch was significantly higher in the patients with intersegmental differences of fibrosis between the RL and the CL (19 out of 25, 76%) than those without such differences (6 out of 32, 19%) (p < 0.001). An expanded gallbladder fossa showed no significant relationship ( p = 0.327) with the segmental difference of the fibrosis grades between the LS and the MS. Conclusion: The relative lack of fibrosis in the CL with more advanced fibrosis in the RL can be a distinguishing feature to differentiate chronic C-viral hepatitis from chronic B-viral hepatitis and this is closely related to the presence of a right posterior hepatic notch. Index terms: Liver cirrhosis; Magnetic resonance imaging; Gadolinium; Iron; Chronic hepatitis B; Chronic hepatitis C

Tuberculosis remains one of the most prevalent and fatal infectious diseases in spite of considerable improvements in medical science. The diagnosis and treatment of extrapulmonary tuberculosis involving the abdomen is still complicated owing to vague or non-specific clinical features. Although rare, isolated splenic involvement is one of the important manifestations of extrapulmonary tuberculosis, and imaging suspicion of the disease is essential. We report a case of surgically confirmed mass-forming splenic tuberculosis showing a layered pattern consisting of caseous necrosis with profound restriction of water molecules surrounded by an irregular rind of granulation tissue with less diffusion restriction on diffusion-weighted magnetic resonance imaging (DWI). In the differential diagnosis of neoplastic or non-neoplastic mass-forming lesions involving the spleen, this unique DWI feature could be helpful in characterizing splenic tuberculosis. The patient has been in clinically disease free status for nearly 20 months after splenectomy.

Purpose To compare abdominal ultrasonographic (AU) findings with endoscopic ultrasonographic (EUS) findings of solid pseudopapillary tumor (SPT) of pancreas. Methods Thirteen patients (M:F = 3:10; mean age, 36 years) with surgically proven SPT were included, who underwent both preoperative AU and EUS. Ultrasonographic findings of 2 modalities were compared according tointernal echo texture, calcification, demarcation, internal septum, and main pancreatic duct dilatation. Results Eight cases showed hypoechogenicity on both AU and EUS. Remaining 5 cases showed different echogenicity on both modalities; hypoechogenicity (n = 3) and isoechogenicity (n = 2) on AU, hyperechogenicity (n = 2), unremarkable internal echogenicity due to dense rim calcification (n = 2), isoechogenicity (n = 1) on EUS. In two cases with dense rim calcification, evaluation of the internal content was more difficult on EUS, compared to AU. Additionally, central punctate calcifications of 2 cases were well seen on both AU and EUS, but 1 case of peripheral calcification was only seen on EUS. All cases showed good demarcation without main pancreatic ductal dilatation or internal septum. Conclusions EUS was superior to AU in the evaluation of internal echo texture (solid or cystic) of pancreatic SPT. However, AU was superior to evaluate the larger size tumor and tumors with dense rim calcification.

The purpose of our study was to evaluate the usefulness of superparamagnetic iron oxide (SPIO)-enhanced MRI for distinguishing focal eosinophilic necrosis (FEN) from hepatic metastasis.Forty-one cases of FEN in 41 patients and 40 hepatic metastases in 40 patients were analyzed on unenhanced and SPIO-enhanced T2-weighted MRI retrospectively. Depending on the extent of the remaining hyperintense area on SPIO-enhanced T2-weighted images compared with the unenhanced images, the lesions were classified into four categories--category 1, less than 25%; category 2, 25-49%; category 3, 50-75%; and category 4, more than 75%--by two independent readers. Contrast-to-noise ratio (CNR) was measured using the same region of interest on unenhanced and SPIO-enhanced T2-weighted images. In three pathologic specimens of FEN, the number of Kupffer cells was compared with that of background hepatic parenchyma.All metastases were classified as category 4, whereas FEN showed various distributions overall (category 1, 45.2%; category 2, 24.6%; category 3, 13.4%; category 4, 17.1%). FEN showed a decrease in CNR (from 7.9 +/- 5.8 to 6.1 +/- 5.6, p0.05), and metastases showed an increase in CNR (from 33.7 +/- 27.0 to 55.0 +/- 44.3, p0.05) after SPIO administration. In biopsy specimens, FEN had many more Kupffer cells (174.7 +/- 120.3 cells/high-power field [hpf]) than background hepatic parenchyma (23.7 +/- 9.8 cells/hpf). When using signal loss categories 1, 2, or 3 or CNR decrease, the accuracy of SPIO enhancement was 88.3%.Unlike hepatic metastases, most of the cases of FEN showed a reduction in the extent of hyperintense area or a decrease in CNR after SPIO administration on the T2-weighted images. Therefore, SPIO-enhanced T2-weighted MRI can help to differentially diagnose FEN from metastases.

Background Dedifferentiated liposarcoma is a high-grade nonlipogenic sarcoma that arises in the background of a preexisting well-differentiated liposarcoma. The purpose of this work is to evaluate the spectrum of radiologic appearance of retroperitoneal dedifferentiated liposarcoma with clinicopathologic features. Methods Radiologic images and clinical histories of 15 patients with histologically verified retroperitoneal dedifferentiated liposarcoma were retrospectively studied. Patients included 11 men and 4 women, with mean age of 55.8 years (range, 36–74 years), and they underwent computed tomography (CT) ( n =15) and magnetic resonance imaging (MRI) ( n =5). Results The mean size of the tumor was 22.6 cm with a range of 9.5–38 cm. Both CT and MRI showed well-circumscribed, large round, or lobulated retroperitoneal mass. The appearance of the tumor was classified as follows: Category I, nonfatty component within predominant fatty mass ( n =5); Category II, focal fatty component within large nonfatty mass ( n =6); Category III, well-defined fatty mass and well-defined nonfatty mass ( n =1); Category IV, two masses with predominantly nonfatty component ( n =3). Conclusion Retroperitoneal dedifferentiated liposarcomas present various spectra of imaging findings. While Categories I and III may suggest dedifferentiated liposarcoma, Categories II and IV may appear as other types of liposarcoma or other malignant retroperitoneal tumor.

Following transcatheter arterial chemoembolisation (TACE), the appearances on CT or MR images are largely related to the chemical and ischaemic insults to the portal tract. Understanding the mechanism of TACE-induced changes is essential for radiologists in order to determine the therapeutic effect as well as to distinguish these changes from recurrent tumours. This pictorial review illustrates the haemodynamic and substantial parenchymal changes related to TACE for hepatic malignancy.

The aim of this study was to retrospectively compare the value of "washout" on dynamic MR imaging with superparamagnetic iron oxide (SPIO)-enhanced imaging features of small hepatocellular carcinoma (HCC). A total of 74 small (5-30 mm) hypervascular HCCs in 42 cirrhotic patients who underwent double contrast material-enhanced MR imaging were evaluated to determine the presence of washout in the portal or equilibrium phase of gadolinium-enhanced dynamic imaging and decreased uptake of SPIO on T2*-weighted imaging. HCCs were verified histologically (n = 13) or by serial follow-up imaging studies (n = 61). According to the size of the lesions, 27 vs. 73% (10 mm, n = 15; P = 0.016 on McNemar test), 39 vs. 79% (10-14 mm, n = 28; P = 0.002), 50 vs. 93% (15-20 mm, n = 14; P = 0.031), and 82 vs. 100% (20 mm, n = 17; P = 0.250) of the lesions showed washout vs. decreased SPIO accumulation respectively. The larger the lesion, the higher the prevalence of washout or decreased SPIO uptake (P = 0.004 or P = 0.036, respectively, on Mantel-Haenszel test). In many small hypervascular HCCs up to 2 cm, SPIO-enhanced MR imaging offers essential information for early diagnosis in the absence of washout on dynamic imaging.

Objective: The purpose of this study was to investigate the early manifestation of hypervascular hepatocellular carcinomas by means of evaluating the "nodule-in-nodule" hepatic lesions depicted on dynamic computed tomography. Methods: For 26 lesions with hypervascular foci in nonhypervascular nodules in 23 patients with cirrhotic liver, the size of the lesions was measured during the initial and follow-up studies in patients who had a comparable follow-up computed tomography or magnetic resonance imaging studies (ranging from 46 to 399 days). Results: The mean volume doubling time of the total 26 inner nodules was 36 days, which was significantly shorter than the doubling time for the outer nodules (mean, 257 days for 18 enlarged lesions) (P < 0.001). Conclusions: Because of the rapid progression of the inner hypervascular hepatocellular carcinomas, recognition of nodule-in-nodule lesions is essential for considering short-term follow-up or immediate treatment when managing patients with cirrhosis.

We report on the 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) findings in a case of adrenocortical oncocytoma, a rare tumor of the adrenal gland with the literature review of other imaging findings including ultrasonography, computed tomography, and magnetic resonance imaging. To our knowledge, there have been no reports published in the English literature about 18F-FDG-PET findings in adrenocortical oncocytoma.

The objective of this study was to investigate the outcome and clinical implications of nonhypervascular hypoattenuating nodules observed on portal or equilibrium phase CT images of cirrhotic livers.One hundred one cirrhotic patients (male:female = 69:32) with hypoattenuating nodules observed on initial portal or equilibrium phase CT images were retrospectively evaluated by follow-up CT performed 6-66 months after the initial CT examination. Depending on the background nodularity, patients were separated into macronodular (n = 33, 288 nodules) and micronodular (n = 68, 346 nodules) cirrhotic groups. Each nodule was categorized as category I (enlarged) or category II (stable). Nodule categories were correlated with the initial lesion size and the pattern of background cirrhosis.The frequency of category I nodules was higher in patients with micronodular cirrhosis (40%) than in those with macronodular cirrhosis (27%) (p = 0.001). Category I nodules were significantly larger than category II nodules in patients with micronodular cirrhosis (p0.001). The doubling times of category I nodules had no statistical difference between patients with micronodular or macronodular cirrhosis (p = 0.954). Of the category I nodules in patients with micronodular cirrhosis, 8.6% showed malignant changes.More careful attention should be paid to large nodules in patients with micronodular cirrhosis because of the potentially greater risk of malignancy, and small hypoattenuating nodules should be more often followed up in shorter intervals than large nodules.

To demonstrate the characteristic feature of hepatic cavernous hemangiomas on ferucarbotran-enhanced T2-weighted MR imaging as a new diagnostic finding.In 201 hepatic lesions (61 hemangiomas, 61 cysts, 41 hepatocellular carcinomas, 31 metastatic carcinomas, and 7 cholangiocarcinomas), lesion-to-liver contrast on ferucarbotran-enhanced T2-weighted images was qualitatively compared with pre-contrast images by three independent readers using a four-grade scale (group 1, marked increase; group 2, mild increase; group 3, no change; group 4, decrease). The change in the contrast-to-noise ratio (CNR) for each lesion was quantitatively measured.Only hemangiomas showed a significant decrease in CNR; 10% and 90% of the hemangiomas were categorized as group 3 and 4 lesions, respectively. Besides the hemangiomas, there was no other lesion categorized into group 4 except for one cyst. When group 4 lesions were considered hemangiomas, the accuracy of identification was 96.4%.Hemangiomas show a significant decrease in lesion-to-liver contrast on T2-weighted images after ferucarbotran injection, which might be another typical diagnostic imaging finding of hemangiomas distinguished from solid malignant lesions.

The purpose of this study was to investigate the natural history of transcatheter arterial chemoembolization (TACE)-induced, transient hepatic attenuation difference (THAD). Among the patients who underwent TACE for treatment of hepatocellular carcinomas during a 32-month period, 32 patients with 40 newly developed THADs defined as localized, transient, peripheral hepatic parenchymal enhancement during the hepatic arterial phase of dynamic CT (axial dimension, 1.9–8.8 cm; mean, 4.9 cm) in the vicinity of iodized-oil accumulation were subjected to a retrospective analysis of serial follow-up CT examinations. Among the 40 TACE-induced THADs, 18 (45%) and 9 (23%) were accompanied with arterial-portal venous fistula (APF) and portal venous stenosis (PVS), respectively, while 2 (5%) THADs showed both APF and PVS simultaneously. Thirty-eight (95%) THADs disappeared spontaneously during the follow-up period (range, 4–26 months; mean, 9 months), and 11 (29%) of them showed progressive atrophy of the corresponding hepatic parenchyma. Regardless of the presence of APF, 10 (91%) of 11 THADs of following parenchymal atrophy had shown PVSs (P