Clinical Applications of Arterial Spin Labeling in Brain Tumors The aim of this review was to review the basic background, technique, and clinical applications of arterial spin labeling in brain tumors. Arterial spin labeling is used for differentiation of brain tumors from nonneoplastic lesions such as infarction and infection. It has a role in the grading of gliomas and in the differentiation of gliomas from lymphomas and metastasis. It is used for detection of the best biopsy site and prediction of treatment response. Arterial spin labeling is used for the assessment of extra-axial tumors and pediatric tumors. Last, it has a role in the differentiation of tumor recurrence from postradiation changes and in monitoring patients after therapy.

Development of a Standardized Grading Scale for Atherosclerotic Disease of the Head and Neck Objective For research and risk factor analysis, a reproducible method quantifying atherosclerosis is necessary. Our aim was to develop a computed tomography (CT) angiography grading system to quantify atherosclerotic disease of the head and neck. Methods Institutional review board–approved, retrospective analysis was performed on 152 patients who underwent head/neck CT angiography. A grading scale was designed to calculate plaque burden at multiple sites with the sum referred to as atherosclerosis score. Three radiologists calculated scores with an overlap of cases to calculate the intraclass correlation coefficient. Results Without any prior training, the intraclass correlation coefficient between readers was considered fair. After a short tutorial, intraclass correlation coefficient was recalculated using separate patients, showing excellent correlation. Statistically significant positive correlation was found between atherosclerosis scale and age, hyperlipidemia, hypertension, and diabetes, but no correlation with sex or smoking status. Conclusions A simple, visual grading scale for atherosclerosis in head/neck CT angiography was used to standardize reporting and better characterize a patient's risk of stroke.

Blood Oxygen Level–Dependent Response Changes in the Ipsilateral Primary Somatosensory Cortex and Thalamus of Patients With Moyamoya Disease During Median Nerve Electrical Stimulation Objective The objective of this study was to investigate the changes in the blood oxygen level–dependent (BOLD) response in the ipsilateral primary somatosensory cortex (SI) and thalamus of patients with moyamoya disease (MMD) during sensory stimulation. Methods Sixty-four MMD patients, and 15 healthy volunteers were enrolled. Thirty-three MMD patients exhibited paroxysmal numbness or hypoesthesia in the unilateral limbs. Fifteen patients with acroparesthesia underwent unilateral encephaloduroarteriosynangiosis (EDAS). All volunteers underwent BOLD functional magnetic resonance imaging (BOLD-fMRI) under median nerve electrical stimulation (MNES). Blood oxygen level–dependent fMRI data were processed to obtain time-signal intensity curves in the activation areas of the bilateral SI and thalamus. Processed dynamic susceptibility contrast-enhanced magnetic resonance imaging data were used to measure the time to peak of the BOLD response in the regions of interest, including the bilateral SI, thalamus, and cerebellum. Changes in the time-signal intensity curve–related hemodynamic parameters in the ipsilateral SI and thalamus were examined between healthy controls, nonacroparesthesia patients, and asymptomatic and symptomatic sides of unilateral acroparesthesia patients during MNES. Changes in these parameters in MMD patients before and after EDAS were examined. Results Compared with healthy volunteers, 3 groups of MMD patients exhibited an increased peak of the positive BOLD response in the ipsilateral thalamus during MNES (0.65 ± 0.24 vs 0.79 ± 0.35, 0.94 ± 0.57, and 0.89 ± 0.50; P = 0.0335). The positive response peak in the ipsilateral SI markedly increased in MMD patients with acroparesthesia during MNES on the asymptomatic side (0.56 ± 0.37 vs 0.38 ± 0.27, P = 0.0243). The time to peak negative response in the ipsilateral SI was prolonged during MNES on the symptomatic side after EDAS (12.14 ± 8.90 seconds vs 18.86 ± 9.20 seconds, P = 0.0201). Conclusions During sensory stimulation treatment, BOLD response changes occurred in the ipsilateral SI and thalamus of MMD patients. These changes enabled the contralateral hemisphere of the brain to better deal with sensory stimuli.

Abnormal Neural Activity in Children With Diffuse Intrinsic Pontine Glioma Had Manifested Deficit in Behavioral Inhibition: A Resting-State Functional MRI Study Purpose The purpose of this study was to investigate whether alterations of regional neural function in children with diffuse intrinsic pontine glioma (DIPG) had manifested deficit in behavioral inhibition using resting-state functional MRI (rs-fMRI). Methods There were 17 participants with DIPG who took part in the study. Eight children were with deficit in behavioral inhibition, whereas the other 9 children did not obtain deficit in behavioral inhibition. Five healthy children with age, sex, and education matched to the study group also participated as the control group. These 3 groups underwent rs-fMRI, and the results were then converted to amplitude of low-frequency fluctuation (ALFF) data. Amplitude of low-frequency fluctuation data were further analyzed by single-factor analysis of variance comparing among 3 groups based on the whole brain levels. Amplitude of low-frequency fluctuation results were subjected to t test of voxel-wised comparison to derive the rs-fMRI brain function differences between the 2 DIPG groups. The Pearson correlation between ALFF values of abnormal regions found in 3 groups and the scores obtained according to the Child Behavior Checklist were analyzed. Results The 3 groups had shown significant differences in terms of the ALFF results, with the ALFF increased in several brain regions (P < 0.05, corrected with AlphaSim, clusters >59 voxels), which include left supramarginal gyrus, left dorsolateral superior frontal gyrus, right precentral gyrus, and right middle frontal gyrus. Participants with deficit in behavioral inhibition had shown significant differences (ALFF decreased) in several brain regions, including left dorsolateral superior frontal gyrus and right fusiform gyrus (P < 0.05, corrected with AlphaSim, clusters >123 voxels), whereas other brain regions had shown ALFF increased, including left supramarginal gyrus, left middle frontal gyrus, and right medial superior frontal gyrus (P < 0.05, corrected with AlphaSim, clusters >123 voxels). There was no significant correlation between ALFF values and Child Behavior Checklist scores (P > 0.05). Conclusions These findings of focal spontaneous hyperfunction and hypofunction, which correlate with deficit in behavioral inhibition processing, and the abnormal brain regions are considered to be inefficient (in regions of the brain that may relate to compensatory brain and behavioral functioning, and it may be that the brain region needs to exert extra energy to perform a task to the same degree as the control group) or inability (inability in a certain region, or underpowered), pointing to a pathophysiologic process in executive dysfunction.

Artifact Reduction in the Diagnosis of Vasospasm in Computed Tomographic Perfusion: Potential of Iterative Metal Artifact Reduction Objective This study aimed to analyze the possibility of artifact reduction using a new iterative metal artifact reduction algorithm (iMAR) in the diagnosis of perfusion deficits due to vasospasms and to evaluate its clinical relevance. Methods Sixty-one volume perfusion computed tomographies of 24 patients after coiling or aneurysm clipping were reconstructed using standard-filtered back-projection and iMAR retrospectively. The degree of artifacts was evaluated as well as the size of the nonevaluable area. Diagnostic performance was evaluated compared with digital subtraction angiography. Results Artifacts were present in 39 of 61 volume perfusion computed tomography examinations. Image quality (score, 1.0 vs 1.6; P < 0.01) was higher and the size of the signal loss was reduced significantly by iMAR (intracranial metal artifacts, 887 mm2 vs 359 mm2 [P < 0.01]; cranial bolt, 3008 mm2 vs 837 mm2 [P < 0.01]). Digital subtraction angiography confirmed vasospasms in 11 (92%) of 12 patients. Conclusion The iMAR yields higher image quality by reducing artifacts compared with filtered back-projection.

The Value of 1H-MRS and MRI in Combined Methylmalonic Aciduria and Homocystinuria Objective The aims of this study were to describe the brain magnetic resonance imaging (MRI) features of methylmalonic aciduria and homocystinuria and to evaluate the additional value of 1H-MRS. Patients and Methods Twenty-eight children with methylmalonic aciduria and homocystinuria were included in this study. The control group included 21 healthy children. All the cases underwent MRI and 1H-MRS before treatment. We measured the N-acetylaspartate (NAA), choline (Cho), creatine (Cr), and myoinositol (mI) peaks in the basal ganglia regions. The NAA/Cr, Cho/Cr, mI/Cr, and NAA/Cho ratios were calculated. We also observed whether there were lactic acid peaks. Result We identified that NAA/Cr and NAA/Cho significantly decreased in the basal ganglia and that 3 patients showed lactate peaks, but other metabolites were not significantly altered. Hydrocephalus and diffuse supratentorial white matter edema were the primary MR findings; 7 patients had thinning of the corpus callosum, and 2 patients had subdural hematoma. Six patients showed normal brain MRI findings. Conclusions Methylmalonic aciduria and homocystinuria patients with metabolite changes in the basal ganglia demonstrate compromised neuronal integrity, and anerobic metabolism occurs in acute encephalopathic episodes. 1H-MRS is a useful tool for evaluating brain damage. Hydrocephalus and diffuse supratentorial white matter edema are the main MRI features.

Usefulness of Diffusion-Weighted Magnetic Resonance Imaging Using Apparent Diffusion Coefficient Values for Diagnosis of Infantile Hemangioma Objective The objective of this study was to determine whether apparent diffusion coefficient (ADC) values obtained from diffusion-weighted imaging allow differentiation between infantile hemangiomas (IHs) and malignant soft tissue tumors. Methods A retrospective review was performed on magnetic resonance images of pediatric patients with IHs and malignant soft tissue tumors from January 2014 to December 2016, which comprised 7 patients with 8 IHs and 6 patients with 6 malignant soft tissue tumors. We calculated and compared the ADC values of each lesion. Receiver operating characteristic curve analysis was performed to determine a cutoff value for the ADC. Results There was a statistically significant difference between the ADC values of IHs and those of malignant soft tissue tumors (1.32 [1.27–1.72] × 10−3 mm2/s vs 0.67 [0.57–0.79] × 10−3 mm2/s; P < 0.001), with no overlap between the 2 groups. Conclusions The ADC values obtained from diffusion-weighted imaging were useful in differentiating IHs from malignant soft tissue tumors in pediatric patients.

Positive Predictive Values of Lumbar Spine Magnetic Resonance Imaging Findings for Provocative Discography Purpose The purpose of this study was to calculate the positive predictive value (PPV) of lumbar spine magnetic resonance imaging (MRI) findings for a painful disc using provocative discography. Materials and Methods Lumbar spine discography records and prediscography MRIs of 736 patients (2457 discs) who underwent discography for diagnostic purposes from 2003 to 2007 were retrospectively reviewed in an Institutional Review Board–exempt and Health Insurance Portability and Accountability Act–compliant protocol. Each level was identified as having high-intensity zone (HIZ) disc, disc protrusion, disc extrusion, or combination (any herniation type), disc bulge, disc degeneration, and spondylolisthesis. Statistical analysis used a 2 × 2 contingency table of significant discography results for each of the MRI variables to calculate P value and PPV with a confidence interval from a binomial distribution. Results An HIZ disc has a PPV of 0.71 (0.65–0.76, P = 4.31E − 44) for a provocative discography. A disc protrusion has a PPV of 0.79 (0.73–0.83, P = 2.68E − 53). A disc extrusion has a PPV of 0.93 (0.79–0.98, P = 1.34E − 14), a bulge of 0.43 (0.37–0.48, P = 0.002), and a degenerative disc of 0.32 (0.28–0.35, P = 0.08), and spondylolisthesis has a PPV of 0.67 (0.59–0.73, P = 1.70E − 20). A herniation of either type (extrusion or protrusion) has a PPV of 0.80 (0.75–0.84, P = 5.86E − 69). Conclusions Disc herniations and HIZ discs have high predictive value in identifying a pain generator. An extruded disc herniation has the highest PPV for discogenic pain.

Coronary Artery Anomalies and Associated Radiologic Findings Coronary anomalies occur in about 1% of the general population and in severe cases can lead to sudden cardiac death. Coronary computed tomography angiography and magnetic resonance imaging have been deemed appropriate for the evaluation of coronary anomalies by accurately allowing the noninvasive depiction of coronary artery anomalies of origin, course, and termination. The aim of this article is to describe and illustrate a comprehensive array for the classification of coronary artery anomalies.

Lesser Known Facts of Small Cell Lung Cancer Until recently, the treatment of small cell lung cancer (SCLC), a malignancy classically described as having a robust response to first-line therapy with near-universal recurrence, has remained relatively unchanged. Advancements in the management of SCLC have lagged behind those seen for non–small cell lung cancers. As the era of precision medicine and targeted immunotherapy evolves, radiologists must be familiar with the modern treatment paradigms of SCLC and associated imaging patterns, including classic and nonclassic appearances of treatment complications.