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.

Superficial small cerebellar infarcts in cerebral amyloid angiopathy on 3 T MRI: A preliminary study.

BACKGROUND: Strictly superficial cerebellar microbleeds and cerebellar superficial siderosis have been considered markers of advanced cerebral amyloid angiopathy (CAA), but there are few studies on cerebellar ischemic lesions in CAA. We investigated the presence of superficial small cerebellar infarct (SCI) ≤15 mm and its relation to magnetic resonance imaging (MRI) markers in patients with probable CAA. METHODS: Eighty patients with probable CAA were retrospectively evaluated. The presence of superficial SCIs was examined, along with cerebellar microbleeds and cerebellar superficial siderosis, using 3-T MRI. Lobar cerebral microbleeds, cortical superficial siderosis (cSS), enlargement of the perivascular space in the centrum semiovale, and white matter hyperintensity were assessed and the total CAA-small vessel disease (SVD) score was calculated. RESULTS: Nine of the 80 patients (11.3%) had a total of 16 superficial SCIs. By tentatively defining SCI <4 mm as cerebellar microinfarcts, 8 out of 16 (50%) superficial SCIs corresponded to cerebellar microinfarcts. The total CAA-SVD score was significantly higher in patients with superficial SCIs (p = 0.01). The prevalence of cSS (p = 0.018), cortical cerebral microinfarct (p = 0.034), and superficial cerebellar microbleeds (p = 0.006) was significantly higher in patients with superficial SCIs. The number of superficial cerebellar microbleeds was also significantly higher in patients with superficial SCIs (p = 0.001). CONCLUSIONS: Our results suggest that in patients with CAA, superficial SCIs (including microinfarcts) on MRI may indicate more severe, advanced-stage CAA. These preliminary findings should be verified by larger prospective studies in the future.

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.

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.

Percutaneous Thermal Ablation for Managing Small Renal Metastatic Tumors.

Purpose: To retrospectively evaluate the treatment outcomes of thermal ablation for renal metastatic tumors. Materials and Methods: Thirteen consecutive patients with small renal metastatic tumors (≤3 cm), who underwent thermal ablation between 2009 and 2020, were included in this study. Eight patients had extra-renal tumors during renal ablation. The primary tumors were adenoid cystic carcinoma in four patients, lung cancer in three, hemangiopericytoma in three, leiomyosarcoma in two, and thyroid cancer in one. The therapeutic effects, safety, survival rate, prognostic factor, and renal function were evaluated. Results: We performed 18 ablation sessions (cryoablation, n = 13; radiofrequency ablation, n = 5) on 19 renal metastases with a mean diameter of 1.7 cm, which resulted in a primary technique efficacy rate of 100% without procedure-related deaths or major complications. Renal function significantly declined 6 months after ablation (P = 0.0039). During the mean follow-up period of 31.2 ± 22.4 months (range, 2.7-71.4 months), one patient had local tumor progression at 11.9 months following radiofrequency ablation. The overall survival rates at 1 and 3 years after ablation were 76.9% (95% confidence interval [CI], 54.0%-99.8%) and 59.3% (95% CI, 31.3%-87.3%), respectively. Tumor size ≥ 2 cm (P = 0.02) and metastasis from non-small cell lung cancer (P = 0.001) were significant worse prognostic factors in univariate analysis, and metastasis from non-small cell lung cancer (P = 0.01) was significant in multivariate analysis. Conclusions: Percutaneous thermal ablation for small renal metastases is safe and feasible and can control local tumors.

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.

Cryptococcus granuloma mimicking local progressed tumor after cryoablation of renal cell carcinoma: A case report.

Infectious granulomas arising in the kidney are rare. However, there are few reports regarding renal granulomas, such as xanthogranulomatous pyelonephritis, sarcoidosis, malakoplakia, and tuberculosis. Here, we report a case of cryptococcal granuloma resembling a locally progressed tumor after percutaneous cryotherapy for renal cell carcinoma. A male patient in his 80s with rheumatoid arthritis underwent computed tomography (CT)-guided cryoablation for biopsy-proven papillary renal cell carcinoma. Follow-up contrast-enhanced CT imaging obtained 4 months after ablation confirmed an enhanced mass on the edge of the ablation zone. There were no symptoms related to the mass. This mass was radiologically diagnosed as local tumor progression and treated with repeated cryoablation. Percutaneous biopsy of the mass was performed immediately after the second cryoablation, and the mass was pathologically diagnosed as granuloma related to Cryptococcus infection. The patient was administered antifungal fluconazole for 1 year with a good outcome.

Hemangioblastoma of the Cerebellopontine Angle Evaluated with Pseudocontinuous Arterial Spin Labeling.

Hemangioblastomas of the cerebellopontine angle (CPA) that emerge extra-axially from the peripheral nervous system are extremely rare. We report a case of hemangioblastoma of the CPA evaluated by pseudocontinuous arterial spin labeling (pCASL). The high rate of tumor blood flow determined using pCASL provided additional useful information for the differential diagnosis of the CPA tumors in this patient.

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.

Fluorescent-based methods for gene knockdown and functional cardiac imaging in zebrafish.

A notable advantage of zebrafish as a model organism is the ease of gene knockdown using morpholino antisense oligonucleotide (MO). However, zebrafish morphants injected with MO for a target protein often show heterogeneous phenotypes, despite controlling the injection volume of the MO solution in all embryos. We developed a method for estimating the quantity of MO injected into each living morphant, based on the co-injection of a control MO labeled with the fluorophore lissamine. By applying this method for knockdown of cardiac troponin T (tnnt2a) in zebrafish, we could efficiently select the partial tnnt2a-depleted zebrafish with a decreased heart rate and impairment of cardiac contraction. To investigate cardiac impairment of the tnnt2a morphant, we performed fluorescent cardiac imaging using Bodipy-ceramide. Cardiac image analysis showed moderate reduction of tnnt2a impaired diastolic distensibility and decreased contraction and relaxation velocities. To the best of our knowledge, this is the first report to analyze the role of tnnt2a in cardiac function in tnnt2a-depleted living animals. Our combinatorial approach can be applied for analyzing the molecular function of any protein associated with human cardiac diseases.

SEMA4A mutations lead to susceptibility to light irradiation, oxidative stress, and ER stress in retinal pigment epithelial cells.

PURPOSE: RP is a retinal degeneration disorder that is caused by mutations of various genes, including semaphorin-4A (SEMA4A). A number of retinal diseases, including RP, are associated with light exposure, oxidative stress, and endoplasmic reticulum (ER) stress. In this study, we investigated whether mutant SEMA4A causes retinal dysfunction via light exposure, oxidative stress, and ER stress. METHODS: Mutant SEMA4A (D345H or F350C) was overexpressed in a human retinal epithelium cell line ARPE19. Intracellular localization of mutant SEMA4A was investigated using confocal laser scanning microscopy. The ARPE-19 cells were also irradiated with white light, and expression of 78 kDa glucose-regulated protein (GRP78), a marker of ER stress, and phagocytosis were measured. The cells were treated with an ER stress inducer, tunicamycin, or an oxidative stressor, H(2)O(2), and cell death was measured. Human SEMA4A mutants were expressed in zebrafish embryos with tunicamycin and mRNA of DNA damage-inducible transcript 3 (ddit3) was measured as an ER stress marker. RESULTS: Mutant SEMA4A was localized in the ER, whereas wild type (WT) SEMA4A was observed in cell membranes. The expression of GRP78 was increased by mutant SEMA4A following light irradiation, and phagocytosis was suppressed in mutant SEMA4A-transfected cells. Mutant SEMA4A induced susceptibility to ER stress and oxidative stress. In zebrafish, human mutant SEMA4A increased ddit3 mRNA compared with WT under the ER stress condition. CONCLUSIONS: Our results suggest that mutations in SEMA4A may cause susceptibility to light exposure, oxidative stress, and ER stress, which may be involved in the progression and pathology of RP.