Young Jin Ryu

Glioma: application of whole-tumor texture analysis of diffusion-weighted imaging for the evaluation of tumor heterogeneity.

Background and Purpose To apply a texture analysis of apparent diffusion coefficient (ADC) maps to evaluate glioma heterogeneity, which was correlated with tumor grade. Materials and Methods Forty patients with glioma (WHO grade II (n = 8), grade III (n = 10) and grade IV (n = 22)) underwent diffusion-weighted imaging (DWI), and the corresponding ADC maps were obtained. Regions of interest containing the lesions were drawn on every section of the ADC map containing the tumor, and volume-based data of the entire tumor were constructed. Texture and first order features including entropy, skewness and kurtosis were derived from the ADC map using in-house software. A histogram analysis of the ADC map was also performed. The texture and histogram parameters were compared between low-grade and high-grade gliomas using an unpaired student’s t-test. Additionally, a one-way analysis of variance analysis with a post-hoc test was performed to compare the parameters of each grade. Results Entropy was observed to be significantly higher in high-grade gliomas than low-grade tumors (6.861±0.539 vs. 6.261±0.412, P  = 0.006). The fifth percentiles of the ADC cumulative histogram also showed a significant difference between high and low grade gliomas (836±235 vs. 1030±185, P = 0.037). Only entropy proved to be significantly different between grades III and IV (6.295±0.4963 vs. 7.119±0.3165, P<0.001). The diagnostic accuracy of ADC entropy was significantly higher than that of the fifth percentile of the ADC histogram (P = 0.0034) in distinguishing high- from low-grade glioma. Conclusion A texture analysis of the ADC map based on the entire tumor volume can be useful for evaluating glioma grade, which provides tumor heterogeneity.

An NMR metabolomics approach for the diagnosis of leptomeningeal carcinomatosis

Leptomeningeal carcinomatosis (LC) is the third most common metastatic complication of the central nervous system. However, the current modalities to reliably diagnose this condition are not satisfactory. Here, we report a preclinical proof of concept for a metabolomics-based diagnostic strategy using a rat LC model incorporating glioma cells that stably express green fluorescent protein. Cytologic diagnoses gave 66.7% sensitivity for the 7-day LC group and 0% for the 3-day LC group. MR imaging could not diagnose LC at these stages. In contrast, nuclear magnetic resonance-based metabolomics on cerebrospinal fluid detected marked differences between the normal and LC groups. Predictions based on the multivariate model provided sensitivity, specificity, and overall accuracy of 88% to 89% in both groups for LC diagnosis. Further statistical analyses identified lactate, acetate, and creatine as specific for the 7-day LC group, with glucose a specific marker of the normal group. Overall, we showed that the metabolomics approach provided both earlier and more accurate diagnostic results than cytology and MR imaging in current use.

Imaging findings of Kaposiform Hemangioendothelioma in children

PURPOSE Kaposiform hemangioendothelioma (KHE) is a rare, aggressive vascular tumor that typically occurs during infancy or early childhood. Though several case reports have discussed the imaging findings of KHE, larger comprehensive studies are lacking. The purpose of this study was to evaluate the imaging findings of KHE in children. MATERIALS AND METHODS A total of twelve cases of pathologically proven KHE were collected by searching our institutions pathology database for children diagnosed between January 2004 and April 2016 (6 male, 6 female; median age: 3 months; age range 7days - 18 years). CT (n=7) and MRI (n=9) findings were retrospectively evaluated. The location, morphology, enhancement, and growth pattern were analyzed. RESULTS KHEs involved various locations: superficial or deep soft tissue of the extremities (n=4); abdomen (n=3; 2 cases, pancreas; 1 case, small bowel), neck and mediastinum (n=1); chest wall, diaphragm, and pericardium (n=1); abdominal wall (n=1); and head (IAC, CP angle) (n=2). Eight of 10 cases (80%) with CT/MR findings were locally invasive and involved two or more adjacent organs. Three cases presented as well-defined solid masses, and seven were associated with infiltrative lesions of the surrounding areas with (n=4) or without definite solid regions (n=3). In nine patients with MRI, all KHEs were heterogeneous and hyperintense to muscles on T2-weighted images (T2WI), while four KHEs consisted of some regions that were nearly isointense to muscle. Eight of the 10 cases with imaging exhibited heterogeneous intense enhancement, while only one demonstrated mild enhancement. Signal voids (n=2), engorged vessels (n=1), calcification (n=3), hemorrhage (n=1), or bone changes (n=4) were infrequently observed. Four patients (33%) had Kasabach-Merritt phenomenon, and recurrence was observed in two cases. CONCLUSION KHEs occurred in various locations, affected mostly infants, and generally exhibited intense heterogeneous enhancement. In more than half of the included cases, KHEs were highly infiltrative and locally invasive with ill-defined margins. Awareness of these features should prompt radiologists to include KHE in the differential diagnosis for pediatric masses.

Acute Symptomatic Basilar Artery Stenosis: MR Imaging Predictors of Early Neurologic Deterioration and Long-term Outcomes

Purpose To determine clinical, laboratory, and radiologic factors associated with early neurologic deterioration (END) and long-term outcomes in patients with medically treated symptomatic basilar artery stenosis (BAS). Materials and Methods The study design was approved by the institutional review board. From a database of all consecutive patients with cerebrovascular ischemia, the authors retrospectively included 292 patients with medically treated symptomatic BAS with at least 70% stenosis of the basilar artery. The authors evaluated various clinical factors, including National Institutes of Health Stroke Scale (NIHSS) score, C-reactive protein (CRP) level, fibrinogen level, and radiologic factors, including diffusion-weighted (DW) magnetic resonance (MR) imaging-based posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS), hyperintense basilar artery at fluid-attenuated inversion recovery (FLAIR) imaging (FLAIR-hyperintense vessel [FHV]), and clot signs. The outcomes were defined as the development of END and with the 90-day modified Rankin Scale score (favorable score: 0-2). The authors performed a χ(2) test, followed by logistic regression analysis, to identify independent outcome predictors. Results The development of END was highly correlated with unfavorable 90-day modified Rankin Scale score (P < .001). The significant predictors for END were CRP level of at least 1.5 mg/dL (P < .001), NIHSS score of at least 4 (P = .002), pc-ASPECTS of 6 or less (P < .001), and proximal FHV (P = .022). Proximal FHV (P = .010), pc-ASPECTS of 6 or less (P = .002), brainstem involvement (P = .036), and NIHSS score of at least 4 (P < .001) were associated with an unfavorable 90-day modified Rankin Scale score. Neither aggressive medical treatment nor delayed intervention was associated with a favorable 90-day modified Rankin Scale score. Conclusion In medically treated symptomatic BAS, MR imaging parameters such as proximal basilar FHV and DW imaging-based pc-ASPECTS have independent prognostic values for END development and long-term outcomes. (©) RSNA, 2016.

Pediatric Chest CT: Wide-Volume and Helical Scan Modes in 320-MDCT

OBJECTIVE The purpose of this study was to compare wide-volume and helical pediatric 320-MDCT of the chest with respect to radiation dose and image quality. MATERIALS AND METHODS From November 2012 to September 2013, 59 wide-volume and 47 helical pediatric chest 320-MDCT images were obtained. The same tube potential and effective tube current-time product were applied in the two groups according to patient weight (group A, < 10 kg, n = 18; group B, 10-19.9 kg, n = 60; group C, 20-39.9 kg, n = 28). To compensate for overranging, adjusted CT dose index (CTDI) was calculated by dividing dose-length product (DLP) by the scan ranges imaged. Adjusted CTDI, DLP, overall image quality, motion artifact, noise, and scan ranges were compared by Mann-Whitney U test or t test. RESULTS The adjusted CTDI was significantly lower in the group who underwent wide-volume CT than in the group who underwent helical CT (weight group A, p < 0.001; group B, p < 0.001; group C, p = 0.003). The DLP was lower in the wide-volume group than in the helical CT group in weight groups A (p < 0.001) and B (p < 0.001) but not in group C (p = 0.162). All CT scans were of diagnostic quality, and there was no significant difference between the wide-volume and helical CT groups (p = 0.318). The motion artifact score was significantly higher in the wide-volume group than in the helical CT group in groups B (p < 0.001) and C (p = 0.010) but not in group A (p = 0.931). The noise was significantly lower in the wide-volume group than in the helical CT group (p < 0.001). CONCLUSION In pediatric chest CT, use of wide-volume CT can decrease radiation exposure while preserving image quality. It is associated with less noise than helical CT but may be subject to more motion artifact.

Progression of Cerebral White Matter Hyperintensities and the Associated Sonographic Index

Purpose To evaluate the relationship between penetrating arterial pulsation and the progression of white matter hyperintensities (WMHs) by using the sonographic resistance index (RI) along the M1 segment of the middle cerebral artery (MCA). Materials and Methods The study design was approved by the institutional review board of Seoul National University Hospital. The study included 450 individuals who had undergone initial transcranial Doppler (TCD) sonography and magnetic resonance imaging, with follow-up imaging performed within 34-45 months, and who had no stenosis of 30% or more in the internal carotid artery or MCA or a history of stroke other than an old lacunar infarction. MRIR was defined as distal RI divided by proximal RI, where the distance between proximal MI and distal M1 was approximately 20 mm based on TCD evaluation. WMH progression was quantitatively evaluated by subtracting WMH volume at baseline from WMH volume at follow-up. Results At baseline, mean MRIR was 0.974 ± 0.045 (standard deviation), and mean WMH volume was 9.66 mL ± 14.54. After a mean of 38.3 months ± 3.4, the WMH volume change was 4.06 mL ± 7.35. WMH volume change was linearly associated with MRIR (r = 0.328, P < .001), along with the baseline WMH volume (r = 0.433, P < .001) and mean MCA pulsatility index (r = 0.275, P = .037). MRIR values greater than or equal to 1.000 were associated with a greater increase in WMH volume (P < .001). Conclusion MRIR might reflect the pulsation of penetrating arteries and is independently associated with WMH progression.

Image quality and radiation dose of brain computed tomography in children: effects of decreasing tube voltage from 120 kVp to 80 kVp

BackgroundComputed tomography (CT) has generated public concern associated with radiation exposure, especially for children. Lowering the tube voltage is one strategy to reduce radiation dose.ObjectiveTo assess the image quality and radiation dose of non-enhanced brain CT scans acquired at 80 kilo-voltage peak (kVp) compared to those at 120 kVp in children.Materials and methodsThirty children who had undergone both 80- and 120-kVp non-enhanced brain CT were enrolled. For quantitative analysis, the mean attenuation of white and gray matter, attenuation difference, noise, signal-to-noise ratio, contrast-to-noise ratio and posterior fossa artifact index were measured. For qualitative analysis, noise, gray-white matter differentiation, artifact and overall image quality were scored. Radiation doses were evaluated by CT dose index, dose-length product and effective dose.ResultsThe mean attenuations of gray and white matter and contrast-to-noise ratio were significantly increased at 80 kVp, while parameters related to image noise, i.e. noise, signal-to-noise ratio and posterior fossa artifact index were higher at 80 kVp than at 120 kVp. In qualitative analysis, 80-kVp images showed improved gray-white differentiation but more artifacts compared to 120-kVp images. Subjective image noise and overall image quality scores were similar between the two scans. Radiation dose parameters were significantly lower at 80 kVp than at 120 kVp.ConclusionIn pediatric non-enhanced brain CT scans, a decrease in tube voltage from 120 kVp to 80 kVp resulted in improved gray-white matter contrast, comparable image quality and decreased radiation dose.

Association of Cardiac Hemodynamic Factors With Severity of White Matter Hyperintensities in Chronic Valvular Heart Disease

Importance The cerebral white matter hyperintensity (WMH) is frequently noted in patients with chronic heart disease. Long-term alteration of cardiac hemodynamics might have an influence on the mechanism of cerebral WMH. Objective To investigate the association between chronically altered cardiac hemodynamics and severity of cerebral WMH in patients with chronic valvular heart disease. Design, Setting, and Participants This cross-sectional analysis identified 303 consecutive patients at a tertiary referral center between 2008 and 2016 who were 50 years or older, and diagnosed with severe chronic valvular heart disease and underwent cardiac catherization, echocardiography, and received brain magnetic resonance imaging. Among these patients, 71 with other demonstrated cardiac disease, central nervous system disease, and/or without sufficient catheterization data were excluded, and the remaining 232 patients were included in further analyses. Exposures The site and mechanism of valve diseases, as well as clinical and medication profiles, were reviewed. Cardiac catheterization parameters such as right atrial (RA) mean pressure, right ventricular pressure, and aortic mean pressure were obtained. Comprehensive echocardiographic hemodynamic markers such as left ventricular (LV) ejection fraction, LV mass index, LV end diastolic volume, cardiac index, and E/e′ ratio were also obtained. Main Outcomes and Measures White matter hyperintensity volume was quantitatively evaluated using volumetric analysis. Results This study included 232 patients (103 men [44.4%] and 129 women [55.6%]; mean [SD] (range) age, 65.6 [8.8] (51-88) years) in the final analysis. The mean (SD) WMH volume was 5.93 (7.14) mL (median [interquartile range], 4.33 [1.33-8.62] mL), and mean (SD) RA pressure was 10.0 (4.7) mm Hg. From the catheterization data, 147 patients (63.4%) were classified as having a disease involving the mitral valve; 93 (40.1%), aortic valve; 37 (15.9%), tricuspid valve; and 4 (1.7%), pulmonary valve. In multivariate linear regression analysis, adjusting the type and mechanism of valve disease and clinical, echocardiographic, and/or other catheterization parameters, WMH volume was linearly associated with mean RA pressure (B coefficient, 0.702; 95% CI, 0.373-1.031; P = .001), along with age (B coefficient, 0.145; 95% CI, 0.029-0.261; P = .01) and mean aortic pressure (B coefficient, 0.112; 95% CI, 0.034-0.190; P = .005). Conclusions and Relevance Mean RA pressure was independently associated with the WMH volume in chronic valvular heart disease. Chronically altered RA hemodynamics might have a distinct influence on the pathomechanism underlying the development of WMH.

Gallbladder wall oedema and ascites are independent predictors of progression to hepatic veno-occlusive disease for children with hematopoietic stem cell transplantation

ObjectivesTo evaluate the predictive value of ultrasonography in children with clinically suspicious hepatic veno-occlusive disease (VOD) after hematopoietic stem cell transplantation (HSCT).MethodsAmong 216 children who underwent HSCT, 70 also underwent colour Doppler ultrasonography. Of these, 59 had only one sign/symptom, which did not fulfil the diagnostic criteria (clinical suspicion of VOD) at that time. VOD was confirmed in 20 patients (VOD group), while 39 had other conditions (non-VOD group). The following findings were reviewed and compared between groups: left portal vein (peak velocity, direction), left hepatic artery (peak-systolic/end-diastolic velocities, resistive index), middle hepatic vein (peak velocity, phasicity), hepatomegaly, splenomegaly, gallbladder wall thickness, and ascites.ResultsThe VOD group showed significantly higher reversed flow in portal vein (P = 0.011), peak systolic velocity of left hepatic artery (P = 0.028), monophasicity of middle hepatic vein (P = 0.015), hepatomegaly (P = 0.001), gallbladder wall thickness (P < 0.001), and ascites (P < 0.001). Multivariate regression revealed that gallbladder wall thickness and ascites (odds ratio = 35.370, 56.393) were associated with VOD.ConclusionsThe presence of reversed flow in portal vein, increased peak systolic velocity of hepatic artery, monophasicity of hepatic vein, hepatomegaly, gallbladder wall thickness, and ascites were significantly associated with progression to VOD in children with clinically suspicious VOD after HSCT.Key Points• Ultrasonography with Doppler can help predict progression to VOD.• Gallbladder wall oedema and ascites are the independent predictors of progression to VOD.

Cystatin C, a potential marker for cerebral microvascular compliance, is associated with white-matter hyperintensities progression.

Cerebral white matter hyperintensities (WMHs) are central MRI markers of the brain aging process, but the mechanisms for its progression remain unclear. In this study, we aimed to determine whether the baseline serum cystatin C level represented one mechanism underlying WMH progression, and whether it was associated with the long-term progression of cerebral WMH volume in MRI. 166 consecutive individuals who were ≥50 years of age and who underwent initial/follow-up MRI evaluations within an interval of 34–45 months were included. Serum cystatin C level, glomerular-filtration rate (GFR), and other laboratory parameters were measured at their initial evaluation and at the end of follow-up. Cerebrovascular risk factors, medications, and blood-pressure parameters were also reviewed. WMH progression rate was measured by subtracting WMH volume at baseline from that at the follow-up using volumetric analysis, divided by the MRI intervals. At baseline, WMH volume was 9.61±13.17 mL, mean GFR was 77.3±22.8 mL/min, and mean cystatin C level was 0.92±0.52 mg/L. After 37.9±3.4 months, the change in WMH volume was 3.64±6.85 mL, the progression rate of WMH volume was 1.18±2.28 mL/year, the mean ΔGFR was 2.4±7.9 mL/min, and the mean Δcystatin C was 0.03±0.34 mg/L. The progression rate of WMH volume was linearly associated with cystatin C level (B coefficient = 0.856; 95% confidence interval [CI] 0.174−1.538; P = 0.014), along with the baseline WMH volume (B = 0.039; 95% CI 0.019−0.059; P<0.001), after adjusting for the conventional vascular risk factors, laboratory parameters, medication profiles, and GFR. Especially, patients with a baseline level of cystatin C ≥1.00 mg/L exhibited a much higher progression rate of WMH as compared with those with a baseline level of cystatin C <1.00 mg/L (1.60±1.91 mL/year vs. 0.82±1.63 mL/year, P = 0.010). We concluded that serum cystatin C level is independently associated with the long-term progression rate of the cerebral WMH volume. Therefore, serum cystatin C level might predict the progression of cerebral WMH.