Evaluation of Intradural Ecchordosis Physaliphora With Three-Dimensional Fluid-Attenuated Inversion Recovery.

OBJECTIVE: This study evaluated the efficacy of 3-dimensional fluid-attenuated inversion recovery (3D FLAIR) for detecting intradural ecchordosis physaliphora (EP). METHODS: We retrospectively determined the presence or absence of intradural EP on 3D FLAIR for 3888 consecutive patients, classifying the EP as "classical" or "possible" and analyzing the prevalence, size, and presence or absence of an intraosseous stalk. Where available, magnetic resonance cisternography images were compared with the 3D FLAIR images. RESULTS: Intradural EP was identified in 50 patients (1.3%): 36 (0.9%) classical and 14 (0.4%) possible. The classical EPs were significantly larger than the possible EPs (P < 0.01). Nine EPs (18.0%) showed an osseous stalk. Magnetic resonance cisternography was performed for 19 EPs (16 classical, 3 possible), detecting all 16 classical EPs but none of the possible EPs. CONCLUSIONS: Classical EPs were detected by 3D FLAIR as with magnetic resonance cisternography. The 3D FLAIR findings suggested a new type of possible EP variant previously unreported.

Cortical Brush Sign: A Novel Finding on Thin-slice 3T Susceptibility-weighted Imaging in Acute Cerebral Infarct and Cerebral Venous Thrombosis.

We observed a new SWI finding, "cortical brush sign," that represents prominent venous structures in the cortex of patients with acute cerebral infarct with or without moyamoya disease and cerebral venous thrombosis. The cortical brush sign disappeared on follow-up SWI in all cases. Cortical brush sign may help to understand the pathophysiology of venous structures in the cortex at acute phase.

A Combination of Amide Proton Transfer, Tumor Blood Flow, and Apparent Diffusion Coefficient Histogram Analysis Is Useful for Differentiating Malignant from Benign Intracranial Tumors in Young Patients: A Preliminary Study.

PURPOSE: To evaluate the amide proton transfer (APT), tumor blood flow (TBF), and apparent diffusion coefficient (ADC) combined diagnostic value for differentiating intracranial malignant tumors (MTs) from benign tumors (BTs) in young patients, as defined by the 2021 World Health Organization classification of central nervous system tumors. METHODS: Fifteen patients with intracranial MTs and 10 patients with BTs aged 0-30 years underwent MRI with APT, pseudocontinuous arterial spin labeling (pCASL), and diffusion-weighted imaging. All tumors were evaluated through the use of histogram analysis and the Mann-Whitney U test to compare 10 parameters for each sequence between the groups. The diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: The APT maximum, mean, 10th, 25th, 50th, 75th, and 90th percentiles were significantly higher in MTs than in BTs; the TBF minimum (min) was significantly lower in MTs than in BTs; TBF kurtosis was significantly higher in MTs than in BTs; the ADC min, 10th, and 25th percentiles were significantly lower in MTs than in BTs (all p < 0.05). The APT 50th percentile (0.900), TBF min (0.813), and ADC min (0.900) had the highest area under the curve (AUC) values of the parameters in each sequence. The AUC for the combination of these three parameters was 0.933. CONCLUSIONS: The combination of APT, TBF, and ADC evaluated through histogram analysis may be useful for differentiating intracranial MTs from BTs in young patients.

Advanced multiparametric MRI and FDG-PET/CT in multinodular and vacuolating neuronal tumor: A pathologically confirmed case.

Multinodular and vacuolating neuronal tumor (MVNT) is a relatively new disease concept proposed in 2013 and was classified as a separate tumor type in 2021 by the World Health Organization (WHO) classification. MVNT can cause seizures but is a benign disease, with no cases of enlargement or postoperative recurrence reported. Recent reports described advanced MRI features in MVNT cases, but the diagnosis of MVNT is usually based on characteristic MRI findings of clusters of nodules. Here, we report advanced multiparametric MRI and FDG-PET/CT findings in a case of MVNT with epileptiform symptoms that was pathologically confirmed by surgery.

Pseudocontinuous Arterial Spin Labeling: Clinical Applications and Usefulness in Head and Neck Entities.

As functional magnetic resonance imaging, arterial spin labeling (ASL) techniques have been developed to provide quantitative tissue blood flow measurements, which can improve the performance of lesion diagnosis. ASL does not require contrast agents, thus, it can be applied to a variety of patients regardless of renal impairments and contrast agent allergic reactions. The clinical implementation of head and neck lesions is limited, although, in recent years, ASL has been increasingly utilized in brain lesions. Here, we review the development of the ASL techniques, including pseudocontinuous ASL (pCASL). We compare readout methods between three-dimensional (3D) turbo spin-echo and 2D echo planar pCASL for the clinical applications of pCASL to head and neck lesions. We demonstrate the clinical usefulness of 3D pCASL for diagnosing various entities, including inflammatory lesions, hypervascular lesions, and neoplasms; for evaluating squamous cell carcinoma (SCC) treatment responses, and for predicting SCC prognosis.

Tumor blood flow and apparent diffusion coefficient histogram analysis for differentiating malignant salivary tumors from pleomorphic adenomas and Warthin's tumors.

We aimed to assess the combined diagnostic value of apparent diffusion coefficient (ADC) and tumor blood flow (TBF) obtained by pseudocontinuous arterial spin labeling (pCASL) for differentiating malignant tumors (MTs) in salivary glands from pleomorphic adenomas (PAs) and Warthin's tumors (WTs). We used pCASL imaging and ADC map to evaluate 65 patients, including 16 with MT, 30 with PA, and 19 with WT. We evaluated all tumors by histogram analyses and compared various characteristics by one-way analysis of variance followed by Tukey post-hoc tests. Diagnostic performance was evaluated by receiver operating characteristic (ROC) curve analysis. There were significant differences in the mean, 50th, 75th, and 90th percentiles of TBF among the tumor types, in the mean TBFs (mL/100 g/min) between MTs (57.47 ± 35.14) and PAs (29.88 ± 22.53, p = 0.039) and between MTs and WTs (119.31 ± 50.11, p < 0.001), as well as in the mean ADCs (× 10-3 mm2/s) between MTs (1.08 ± 0.28) and PAs (1.60 ± 0.34, p < 0.001), but not in the mean ADCs between MTs and WTs (0.87 ± 0.23, p = 0.117). In the ROC curve analysis, the highest areas under the curves (AUCs) were achieved by the 10th and 25th percentiles of ADC (AUC = 0.885) for differentiating MTs from PAs and the 50th percentile of TBF (AUC = 0.855) for differentiating MTs from WTs. The AUCs of TBF, ADC, and combination of TBF and ADC were 0.850, 0.885, and 0.950 for MTs and PAs differentiation and 0.855, 0.814, and 0.905 for MTs and WTs differentiation, respectively. The combination of TBF and ADC evaluated by histogram analysis may help differentiate salivary gland MTs from PAs and WTs.

Central nervous system involvement of systemic ALK-positive histiocytosis with KIF5B-ALK fusion.

ALK-positive histiocytosis is an emerging histiocytic entity that can involve a single organ or multiple organs. This disease frequently involves the central nervous system, and the importance of immunohistochemical and genetic analyses is emphasized for the accurate diagnosis of this rare entity. However, radiological findings of this disease have not been sufficiently described. Here, we report a case of a 3-year-old boy with ALK-positive histiocytosis with systemic masses that was identified to harbor KIF5B-ALK gene fusion.

A case of a rosette-forming glioneuronal tumor arising from the pons with disappearance of contrast enhancement.

A rosette-forming glioneuronal tumor (RGNT) is a rare and slow-growing central nervous system tumor. This tumor is usually assessed by MRI during the follow-up period. RGNT can show alteration of contrast enhancement regardless of tumor growth. Here, we report a case of RGNT arising from pons which shows partial enhancement on initial MRI, smaller enhancement on follow-up MRI at 10 months, and totally disappeared at 18 months without any therapy.

Ipilimumab-induced hypophysitis involving the optic tracts and tuber cinereum evaluated using 3D fluid-attenuated inversion recovery.

Ipilimumab, a human monoclonal antibody against cytotoxic T-lymphocyte antigen 4, was approved by the U.S. FDA (Food and Drug Administration) in 2011 for the treatment of unresectable or metastatic malignant melanoma. Occurrence of hypophysitis, an immune-related adverse event due to ipilimumab use, has been frequently reported. We report a case of ipilimumab-induced hypophysitis involving the optic tracts and tuber cinereum, identified using 3D fluid-attenuated inversion recovery.

Cervical spondylosis: Evaluation of microstructural changes in spinal cord white matter and gray matter by diffusional kurtosis imaging.

INTRODUCTION: We investigated microstructural changes in the spinal cord, separately for white matter and gray matter, in patients with cervical spondylosis by using diffusional kurtosis imaging (DKI). METHODS: We studied 13 consecutive patients with cervical myelopathy (15 affected sides and 11 unaffected sides). After conventional magnetic resonance (MR) imaging, DKI data were acquired by using a 3T MR imaging scanner. Values for fractional anisotropy (FA), apparent diffusion coefficient (ADC), and mean diffusional kurtosis (MK) were calculated and compared between unaffected and affected spinal cords, separately for white matter and gray matter. RESULTS: Tract-specific analysis of white matter in the lateral funiculus showed no statistical differences between the affected and unaffected sides. In gray matter, only MK was significantly lower in the affected spinal cords than in unaffected spinal cords (0.60±0.18 vs. 0.73±0.13, P=0.0005, Wilcoxon's signed rank test). CONCLUSIONS: MK values in the spinal cord may reflect microstructural changes and gray matter damage and can potentially provide more information beyond that obtained with conventional diffusion metrics.