Comparison of the Data of a Next-Generation Sequencing Panel from K-MASTER Project with That of Orthogonal Methods for Detecting Targetable Genetic Alterations / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#K-MASTER project is a Korean national precision medicine platform that screened actionable mutations by analyzing next-generation sequencing (NGS) of solid tumor patients. We compared gene analyses between NGS panel from the K-MASTER project and orthogonal methods. @*Materials and Methods@#Colorectal, breast, non–small cell lung, and gastric cancer patients were included. We compared NGS results from K-MASTER projects with those of non-NGS orthogonal methods (KRAS, NRAS, and BRAF mutations in colorectal cancer [CRC]; epidermal growth factor receptor [EGFR], anaplastic lymphoma kinase [ALK] fusion, and reactive oxygen species 1 [ROS1] fusion in non–small cell lung cancer [NSCLC], and Erb-B2 receptor tyrosine kinase 2 (ERBB2) positivity in breast and gastric cancers). @*Results@#In the CRC cohort (n=225), the sensitivity and specificity of NGS were 87.4% and 79.3% (KRAS); 88.9% and 98.9% (NRAS); and 77.8% and 100.0% (BRAF), respectively. In the NSCLC cohort (n=109), the sensitivity and specificity of NGS for EGFR were 86.2% and 97.5%, respectively. The concordance rate for ALK fusion was 100%, but ROS1 fusion was positive in only one of three cases that were positive in orthogonal tests. In the breast cancer cohort (n=260), ERBB2 amplification was detected in 45 by NGS. Compared with orthogonal methods that integrated immunohistochemistry and in situ hybridization, sensitivity and specificity were 53.7% and 99.4%, respectively. In the gastric cancer cohort (n=64), ERBB2 amplification was detected in six by NGS. Compared with orthogonal methods, sensitivity and specificity were 62.5% and 98.2%, respectively. @*Conclusion@#The results of the K-MASTER NGS panel and orthogonal methods showed a different degree of agreement for each genetic alteration, but generally showed a high agreement rate.

Prevalence and correlates of highly caffeinated beverage consumption among Korean adolescents

Objectives@#The purposes of this study were to (1) examine the multi-year prevalence of highly caffeinated beverage (HCB) consumption, (2) identify sex differences in the prevalence, and (3) investigate relationships between HCB consumption and behavioral characteristics in a nationally representative sample of Korean adolescents. @*Methods@#Data from the Korea Youth Risk Behavior Web-based Survey (2014–2017) were analyzed. @*Results@#HCB consumption was higher in 2017 than 2014 (23.9% vs. 12.0%), and higher among boys than girls (17.2% vs. 13.1%). HCB drinkers were more likely to (1) be boys, (2) be overweight or obese, (3) use alcohol and tobacco, (4) consume soda at least once per week, (5) consume sweetened beverages at least once per week, (6) have seriously considered suicide during the past 12 months, and (7) have attempted suicide during the past 12 months (p<0.05 for all). @*Conclusion@#Effective programs to curb HCB consumption among Korean adolescents need to be established.

Clinical Application of Targeted Deep Sequencing in Metastatic Colorectal Cancer Patients: Actionable Genomic Alteration in K-MASTER Project / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Next-generation sequencing (NGS) can facilitate precision medicine approaches in metastatic colorectal cancer (mCRC) patients. We investigated the molecular profiling of Korean mCRC patients under the K-MASTER project which was initiated in June 2017 as a nationwide precision medicine oncology clinical trial platform which used NGS assay to screen actionable mutations. @*Materials and Methods@#As of 22 January 2020, total of 994 mCRC patients were registered in K-MASTER project. Targeted sequencing was performed using three platforms which were composed of the K-MASTER cancer panel v1.1 and the SNUH FIRST Cancer Panel v3.01. If tumor tissue was not available, cell-free DNA was extracted and the targeted sequencing was performed by Axen Cancer Panel as a liquid biopsy. @*Results@#In 994 mCRC patients, we found 1,564 clinically meaningful pathogenic variants which mutated in 71 genes. Anti-EGFR therapy candidates were 467 patients (47.0%) and BRAF V600E mutation (n=47, 4.7%), deficient mismatch repair/microsatellite instability–high (n=15, 1.5%), HER2 amplifications (n=10, 1.0%) could be incorporated with recently approved drugs. The patients with high tumor mutation burden (n=101, 12.7%) and DNA damaging response and repair defect pathway alteration (n=42, 4.2%) could be enrolled clinical trials with immune checkpoint inhibitors. There were more colorectal cancer molecular alterations such as PIK3CA, KRAS G12C, atypical BRAF, and HER2 mutations and even rarer but actionable genes that approved or ongoing clinical trials in other solid tumors. @*Conclusion@#K-MASTER project provides an intriguing background to investigate new clinical trials with biomarkers and give therapeutic opportunity for mCRC patients.

Attenuation-Based Automatic Tube Potential Selection in Cerebral Computed Tomography Angiography: Effects on Radiation Exposure and Image Quality

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.

Pseudoglandular Formation in Hepatocellular Carcinoma Determines Apparent Diffusion Coefficient in Diffusion-Weighted MRI

PURPOSE: To determine the impact of pseudoglandular formation on apparent diffusion coefficient (ADC) values of hepatocellular carcinoma (HCC) in diffusion-weighted imaging (DWI), and to validate the results using histopathological grades. MATERIALS AND METHODS: We assessed 182 HCCs surgically resected from 169 consecutive patients. Each type of tumor pseudoglandular formation was categorized into “non-,” “mixed-,” or “pure-,” based on official histopathology reports. The ADC for each tumor was independently measured, using the largest region of interest on the ADC map. Data were assessed using the analysis of variance test, with Bonferroni correction for post hoc analysis to stratify the relationship of ADCs with pseudoglandular formation, followed by subgroup analysis according to the histopathological tumor grades. RESULTS: The mean ADC was significantly higher in pure pseudoglandular lesions (n = 5, 1.29 ± 0.08 × 10−3 mm2/s) than in non-pseudoglandular lesions (n = 132, 1.08 ± 0.17 × 10−3 mm2/s; P = 0.003) or mixed-pseudoglandular lesions (n = 45, 1.16 ± 0.24 × 10−3 mm2/s; P = 0.034). The ADC values and pseudoglandular formation were significantly correlated in moderately differentiated HCCs (n = 103; r = 0.307, P = 0.007), while well- (n = 19) and poorly-differentiated HCCs (n = 60) did not show significant correlation (r = 0.105 and 0.068, respectively; P = 0.600 and 0.685, respectively). CONCLUSION: The degree of pseudoglandular formation could be one of the determinants of ADC in DWI of HCCs-especially moderately differentiated HCCs-while its influence does not appear to be significant in well- or poorly differentiated HCCs.

Polymorphism of Nitric Oxide Synthase 1 Affects the Clinical Phenotypes of Ischemic Stroke in Korean Population

OBJECTIVE: To investigate whether four single nucleotide polymorphisms (SNPs) rs2293054 [Ile734Ile], rs1047735 [His902His], rs2293044 [Val1353Val], rs2682826 (3'UTR) of nitric oxide synthase 1 (NOS1) are associated with the development and clinical phenotypes of ischemic stroke. METHODS: We enrolled 120 ischemic stroke patients and 314 control subjects. Ischemic stroke patients were divided into subgroups according to the scores of the National Institutes of Health Stroke Survey (NIHSS, <6 and ≥6) and Modified Barthel Index (MBI, <60 and ≥60). SNPStats, SNPAnalyzer, and HelixTree programs were used to calculate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. Multiple logistic regression models were performed to analyze genetic data. RESULTS: No SNPs of the NOS1 gene were found to be associated with ischemic stroke. However, in an analysis of clinical phenotypes, we found that rs2293054 was associated with the NIHSS scores of ischemic stroke patients in codominant (p=0.019), dominant (p=0.007), overdominant (p=0.033), and log-additive (p=0.0048) models. Also, rs2682826 revealed a significant association in the recessive model (p=0.034). In allele frequency analysis, we also found that the T alleles of rs2293054 were associated with lower NIHSS scores (p=0.007). Respectively, rs2293054 had a significant association in the MBI scores of ischemic stroke in codominant (p=0.038), dominant (p=0.031), overdominant (p=0.045), and log-additive (p=0.04) models. CONCLUSION: These results suggest that NOS1 may be related to the clinical phenotypes of ischemic stroke in Korean population.

Diffusion-Weighted MRI of Malignant versus Benign Portal Vein Thrombosis

OBJECTIVE: To validate the diffusion-weighted MRI (DWI) for differentiation of benign from malignant portal vein thrombosis. MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study and waived informed consent. A total of 59 consecutive patients (52 men and 7 women, aged 40-85 years) with grossly defined portal vein thrombus (PVT) on hepatic MRI were retrospectively analyzed. Among them, liver cirrhosis was found in 45 patients, and hepatocellular carcinoma in 47 patients. DWI was performed using b values of 50 and 800 sec/mm2 at 1.5-T unit. A thrombus was considered malignant if it enhanced on dynamic CT or MRI; otherwise, it was considered bland. There were 18 bland thrombi and 49 malignant thrombi in 59 patients, including 8 patients with simultaneous benign and malignant PVT. Mean apparent diffusion coefficients (ADCs) of benign and malignant PVTs were compared by using Mann-Whitney U test. Diagnostic accuracy was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: The mean ADC ± standard deviation of bland and malignant PVT were 1.00 ± 0.39 × 10(-3) mm2/sec and 0.92 ± 0.25 × 10(-3) mm2/sec, respectively; without significant difference (p = 0.799). The area under ROC curve for ADC was 0.520. An ADC value of > 1.35 × 10(-3) mm2/sec predicted bland PVT with a specificity of 94.6% (95% confidence interval [CI]: 84.9-98.9%) and a sensitivity of 22.2% (95% CI: 6.4-47.6%), respectively. CONCLUSION: Due to the wide range and considerable overlap of the ADCs, DWI cannot differentiate the benign from malignant thrombi efficiently.

Radiation Doses of Various CT Protocols: a Multicenter Longitudinal Observation Study

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.

Bilateral Cranial IX and X Nerve Palsies After Mild Traumatic Brain Injury

We report a 57-year-old man with bilateral cranial nerve IX and X palsies who presented with severe dysphagia. After a mild head injury, the patient complained of difficult swallowing. Physical examination revealed normal tongue motion and no uvular deviation. Cervical X-ray findings were negative, but a brain computed tomography revealed a skull fracture involving bilateral jugular foramen. Laryngoscopy indicated bilateral vocal cord palsy. In a videofluoroscopic swallowing study, food residue remained in the vallecula and pyriform sinus, and there was reduced motion of the pharynx and larynx. Electromyography confirmed bilateral superior and recurrent laryngeal neuropathy.

Prognostic value of gallbladder wall thickening in patients with acute hepatitis A

PURPOSE: To investigate the clinical significance of gallbladder (GB) wall thickening frequently observed in patients with acute hepatitis A. METHODS: A total of 328 consecutive patients who were diagnosed with acute hepatitis A and underwent abdominal ultrasonography were enrolled retrospectively. Patients were divided into two groups: GB wall thickening (> or =3 mm, group A) and no thickening (group B). Group A was subdivided into two subgroups (GB wall thickening of > or =10 mm, group A-1 and > or =3 mm to <10 mm, group A-2). The laboratory results related to liver function, hospitalization duration, and time to normalization of liver function were compared between the groups. RESULTS: A total of 230 patients showed GB wall thickening (group A). Besides gamma-glutamyl transpeptidase and alkaline phosphatase, all laboratory results of group A were significantly higher than those of group B (P<0.05). Compared with group B, the hospitalization duration and the time to normalization of liver function were significantly longer in group A (P<0.05). Group A-1 included 146 patients and group A-2 included 84 patients. No significant differences in laboratory results, hospitalization duration, and time to normalization of liver function were found between the two subgroups. In the multivariate logistic regression analysis, serum alanine transaminase, total bilirubin and albumin levels, and hospitalization duration were significantly associated with GB wall thickening in patients with hepatitis A. CONCLUSION: The presence of GB wall thickening in patients with acute hepatitis A suggests a poorer prognosis irrespective of the degree of GB wall thickening or the degree of liver enzyme elevation.

DialysisNet: Application for Integrating and Management Data Sources of Hemodialysis Information by Continuity of Care Record / 대한의료정보학회지

OBJECTIVES: Health Avatar Beans was for the management of chronic kidney disease and end-stage renal disease (ESRD). This article is about the DialysisNet system in Health Avatar Beans for the seamless management of ESRD based on the personal health record. METHODS: For hemodialysis data modeling, we identified common data elements for hemodialysis information (CDEHI). We used ASTM continuity of care record (CCR) and ISO/IEC 11179 for the compliance method with a standard model for the CDEHI. According to the contents of the ASTM CCR, we mapped the CDHEI to the contents and created the metadata from that. It was transformed and parsed into the database and verified according to the ASTM CCR/XML schema definition (XSD). DialysisNet was created as an iPad application. The contents of the CDEHI were categorized for effective management. For the evaluation of information transfer, we used CarePlatform, which was developed for data access. The metadata of CDEHI in DialysisNet was exchanged by the CarePlatform with semantic interoperability. RESULTS: The CDEHI was separated into a content list for individual patient data, a contents list for hemodialysis center data, consultation and transfer form, and clinical decision support data. After matching to the CCR, the CDEHI was transformed to metadata, and it was transformed to XML and proven according to the ASTM CCR/XSD. DialysisNet has specific consideration of visualization, graphics, images, statistics, and database. CONCLUSIONS: We created the DialysisNet application, which can integrate and manage data sources for hemodialysis information based on CCR standards.

Preoperative Evaluation of Lower Rectal Cancer by Pelvic MR with and without Gel Filling

PURPOSE: To assess the usefulness of rectal filling using ultrasonographic gel in patients with lower rectal cancer. MATERIALS AND METHODS: Twenty five patients with lower rectal cancer were enrolled. High resolution pelvic MR was performed twice before and after gel filling. Independently and retrospectively, two radiologists reviewed each set of MR images using five-grade scales for sphincter involvement, CRM (circumferential resection margin) involvement and depiction of the tumor. Same two radiologists retrospectively performed consensus review of each set of MR images for tumor distance from the anal verge and T&N staging. RESULTS: Tumor depiction scores from MR with gel filling were significantly higher than those of MR without distention (p0.05). Distance from the anal verge was significantly different between MR with gel filling and rigid endoscopy (6.8 +/- 1.6 cm vs. 5.8 +/- 1.6 cm, p=0.001). There were no significant differences between pathological staging and MR staging with or without gel filling. CONCLUSION: MR with gel filling improved tumor depiction. And also MR with gel filling revealed same ability for the predictions of CRM or sphincter invasion in patients with lower rectal cancer, comparing with MR without gel filling.

Lifelog Agent for Human Activity Pattern Analysis on Health Avatar Platform / 대한의료정보학회지

OBJECTIVES: To provide accurate personalized medical care, it is necessary to gather individual-related data or contextual information regarding the target person. Nowadays a large number of people possess smartphones, which enables sensors in the smartphones to be used for lifelogging. The objective of the study is to analyze human activity pattern by using lifelog agent cooperating with the Health Avatar platform. METHODS: Using the lifelog measured by accelerometer and gyroscope in a smartphone at a 50 Hz rate, the agent reveals how long the user walks, runs, sits, stands, and lies down, and this information is summarized by hours. The summaries are sent to the Health Avatar platform and finally are written in the Continuity of Care Record (CCR) format. RESULTS: The lifelog agent is successfully operated with the Health Avatar platform. In addition, we implement an application that displays the user's activity patterns in a graph and calculates the metabolic equivalent of task based calorie burned by hour or by day using the lifelog of the CCR form to show that the lifelog can be used as medical records. CONCLUSIONS: The agent shows how lifelogs are analyzed and summarized to help activity recognition. We believe that our agent demonstrates a way of incorporating lifelogs into medical care and a way of exploiting lifelogs in a medical format.

CT Venography for Deep Vein Thrombosis Using a Low Tube Voltage (100 kVp) Setting Could Increase Venous Enhancement and Reduce the Amount of Administered Iodine

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 (CNRVEIN), DVT-to-vein contrast-to-noise ratio (CNRDVT), and subjective degree of venous enhancement and image quality. RESULTS: Venous attenuation and CNRVEIN 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 CNRDVT 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 CNRVEIN. Furthermore, it enables to reduce the amount of administered iodine while maintaining venous attenuation, as compared with the 120 kVp setting.

Boys with precocious or early puberty: incidence of pathological brain magnetic resonance imaging findings and factors related to newly developed brain lesions

PURPOSE: Brain magnetic resonance imaging (MRI) findings and factors predictive of pathological brain lesions in boys with precocious puberty (PP) or early puberty (EP) were investigated. METHODS: Sixty-one boys with PP or EP who had brain MRI performed were included. PP was classified into the central or peripheral type. Brain MRI findings were categorized into group I (pathological brain lesion known to cause puberty; newly diagnosed [group Ia] or previously diagnosed [group Ib]); group II (brain lesion possibly related to puberty); and group III (incidental or normal findings). Medical history, height, weight, hormone test results, and bone age were reviewed. RESULTS: Brain lesions in groups I and II were detected in 17 of 23 boys (74%) with central PP, 9 of 30 boys (30%) with EP, and 7 of 8 boys (88%) with peripheral PP. All brain lesions in boys with peripheral PP were germ cell tumors (GCT), and 3 lesions developed later during follow-up. Group I showed earlier pubertal onset (P<0.01) and greater bone age advancement (P<0.05) than group III. Group III had lower birth weight and fewer neurological symptoms than "Ia and II" (all P<0.05). CONCLUSION: Earlier onset of puberty, greater bone age advancement, and/or neurological symptoms suggested a greater chance of pathological brain lesions in boys with central PP or EP. All boys with peripheral PP, even those with normal initial MRI findings, should be evaluated for the emergence of GCT during follow-up.

Growth after Hematopoietic Stem Cell Transplantation in Children with Acute Myeloid Leukemia

Previous studies have shown that hematopoietic stem cell transplantation (HSCT) may result in growth impairment. The purpose of this study was to evaluate the growth during 5 yr after HSCT and to determine factors that influence final adult height (FAH). We retrospectively reviewed the medical records of acute myeloid leukemia (AML) patients who received HSCT. Among a total of 37 eligible patients, we selected 24 patients who began puberty at 5 yr after HSCT (Group 1) and 19 patients who reached FAH without relapse (Group 2). In Group 1, with younger age at HSCT, sex, steroid treatment, hypogonadism and hypothyroidism were not significantly associated with growth impairment 5 yr after HSCT. History of radiotherapy (RT) significantly impaired the 5 yr growth after HSCT. Chronic graft-versus-host disease (cGVHD) only temporarily impaired growth after HSCT. In Group 2, with younger age at HSCT, steroid treatment and hypogonadism did not significantly reduce FAH. History of RT significantly reduced FAH. Growth impairment after HSCT may occur in AML patients, but in patients without a history of RT, growth impairment seemed to be temporary and was mitigated by catch-up growth.

Hepatic Cavernous Hemangiomas: Relationship between Speed of Intratumoral Enhancement during Dynamic MRI and Apparent Diffusion Coefficient on Diffusion-Weighted Imaging

OBJECTIVE: To investigate the relationships between the apparent diffusion coefficients (ADCs) on diffusion-weighted imaging (DWI) and the speed of contrast-enhancement in hepatic hemangiomas. MATERIALS AND METHODS: Sixty-nine hepatic hemangiomas (> or = 1 cm) were evaluated with DWI, by using multiple b values (b = 50, 400, 800 s/mm2), followed by a gadolinium-enhanced dynamic MRI. The lesions were classified into three groups, according to the speed of contrast-enhancement on the portal phase. ADCs were measured on the ADC map automatically, and were calculated by using the two different b values (mADC50-400 with b values = 50 and 400; mADC400-800 with b values = 400 and 800 s/mm2). RESULTS: The mean ADCs (x 10-3 mm2/s) were significantly higher in the rapid group (1.9 +/- 0.44) than in the intermediate (1.7 +/- 0.35, p = 0.046) or the slow groups (1.4 +/- 0.34, p = 0.002). There were significant differences between the rapid and the slow groups in mADC50-400 (2.12 vs. 1.48; p = 0.008) and mADC400-800 (1.68 vs. 1.22, p = 0.010), and between the rapid and the intermediate groups in mADC50-400 (2.12 vs. 1.79, p = 0.049). Comparing mADC50-400 with mADC400-800, there was a significant difference only in the rapid group (p = 0.001). CONCLUSION: Higher ADCs of rapidly-enhancing hemangiomas may be related to richer intralesional vascular perfusion. Also, the restricted diffusion may be attributed to the difference of structural characteristics of hemangioma.

Diffusion-Weighted MR Imaging before and after Contrast Enhancement with Superparamagnetic Iron Oxide for Assessment of Hepatic Metastasis

PURPOSE: The purpose of our study was to validate diffusion-weighted MRI (DWI) before and after superparamagnetic iron oxide (SPIO) injection for assessment of hepatic metastases. MATERIALS AND METHODS: Eighty-six hepatic metastases (size range, 0.3-4.7 cm; mean, 1.5 cm) verified pathologically or by follow-up imaging studies in 22 consecutive patients (17 men and 5 women; 44-83 years; mean age, 60 years) during a 13-month period were enrolled. Hepatic MRI, including DWI (b-factors=50, 400, 800 s/mm2) with breath-holding technique of single-shot spin-echo echo-planar imaging (TR/TE=1000/69 ms, average=2) before and after SPIO administration, were retrospectively reviewed by two independent radiologists with a 5-point scale confidence score for each hepatic lesion on pre-contrast DWI (pre-DWI), SPIO-enhanced DWI (SPIO-DWI), and SPIO-enhanced T2*-weighted imaging (SPIO-T2*wI). RESULTS: For all lesions, SPIO-T2*wI showed significantly higher confidence score in the diagnosis of hepatic metastases than pre-contrast or SPIO-DWI regardless of the size of b-factors (p0.05). Pre-DWI using b-factor=50 sec/mm2 was also comparable with SPIO-T2*wI by observer 1 (p=0.060). CONCLUSION: Pre-DWI has a limited value for the assessment of hepatic metastases, however, the repetition of DWI after SPIO injection using small b-factors could complement SPIO-T2*wI, especially for subcentimeter lesions.

Focal Liver Lesion Detection in Gadoxetic Acid-enhanced Liver MRI: Effects of Scan Delay, Hepatic Function, and Magnetic Field Strength

PURPOSE: To determine the effects of scan delay, hepatic function, and magnetic field strength on the performance of gadoxetic acid enhanced magnetic resonance imaging. MATERIALS AND METHODS: Gadoxetic acid enhanced MRI conducted in 72 patients with 10 minutes and 20 minutes delay were reviewed retrospectively. For quantitative analysis, liver-to-lesion signal difference ratio (SDR) was measured and compared according to scan delay time, hepatic function and magnetic field strength. For qualitative analysis, two board-certificated radiologists reviewed 10-minute delay and 20-minute delay images. The sensitivity and specificity of each reader was compared. RESULTS: The SDR of 20-minute images in non-cirrhotic patients was significantly higher (p 0.05) to 10-min delay images. In comparisons according to the magnetic strength, there was no significant difference between 1.5-T and 3.0-T systems. Comparisons of ROC curves showed no statistically significant differences in sensitivity and specificity between 10-minute and 20-minute delay images. CONCLUSION: An increase in the liver-to-lesion signal difference ratio was dependent on the patients' hepatic function but not dependent on the magnetic strength. There was no significant difference in sensitivity or specificity between the 10-minute and 20-minute delay images.

A Case of Mass-Forming Splenic Tuberculosis: MRI Findings with Emphasis of Diffusion-Weighted Imaging Characteristics

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.