村山 和宏

PURPOSE: The use of tablet terminals has been explored in various medical settings; however, caution should be exercised when performing image diagnosis using this technology. The present study examined the characteristics of an iPad Air™ monitor and assessed radiographic image interpretations to verify the reliability of the telediagnosis of acute cerebral infarction based on magnetic resonance imaging (MRI) using a tablet terminal. MATERIALS AND METHODS: The luminance of the iPad Air™ was measured using a UA-10 analyzer, and radiographic image interpretation experiments were performed in 100 patients who underwent MRI within 6 h of symptom onset. Ten physicians viewed the images on the iPad Air™ and a medical monitor, with an interval of 2 months between each interpretation. RESULTS: When the iPad Air™ screen was pure white, the contour lines revealed nonuniform luminance distribution. In the reading experiment, the areas under the curve of the medical monitor and the iPad Air™ were 0.9311 and 0.9431, respectively. No significant difference was observed between the medical monitor and the iPad Air™ (p = 0.113). CONCLUSION: The results of the observer performance studies for detecting acute ischemic cerebrovascular disorders on an iPad Air™ were found to be similar to those on a medical monitor.

Noncontrast computed tomography (NCCT) has been used for the detection of early ischemic change (EIC); however, correct interpretation of NCCT findings requires much clinical experience. This study aimed to assess the accuracy of time maximum intensity projection computed tomography technique (tMIP), which reflects the maximum value for the time phase direction from the dynamic volume data for each projected plane, for detection of EIC, against that of NCCT.Retrospective review of NCCT, cerebral blood volume in CT perfusion (CTP-CBV), and tMIP of 186 lesions from 280 regions evaluated by Alberta Stroke Program Early CT Score (ASPECTS) in 14 patients with acute middle cerebral artery stroke who had undergone whole-brain CTP using 320-row area detector CT was performed. Four radiologists reviewed EIC on NCCT, CTP-CBV, and tMIP in each ASPECTS region at onset using the continuous certainty factor method. Receiver operating characteristic analysis was performed to compare the relative performance for detection of EIC. The correlations were evaluated.tMIP-color showed the best discriminative value for detection of EIC. There were significant differences in the area under the curve for NCCT and tMIP-color, CTP-CBV (P < .05). Scatter plots of ASPECTS showed a positive significant correlation between NCCT, tMIP-gray, tMIP-color, and the follow-up study (NCCT, r = 0.32, P = .0166; tMIP-gray, r = 0.44, P = .0007; tMIP-color, r = 0.34, P = .0104).Because tMIP provides a high contrast parenchymal image with anatomical and vascular information in 1 sequential scan, it showed greater accuracy for detection of EIC and predicted the final infarct extent more accurately than NCCT based on ASPECTS.

PURPOSE: We evaluated the diagnostic performance of histogram analysis of data from a combination of dynamic susceptibility contrast (DSC)-MRI and dynamic contrast-enhanced (DCE)-MRI for quantitative differentiation between central nervous system lymphoma (CNSL) and high-grade glioma (HGG), with the aim of identifying useful perfusion parameters as objective radiological markers for differentiating between them. METHODS: Eight lesions with CNSLs and 15 with HGGs who underwent MRI examination, including DCE and DSC-MRI, were enrolled in our retrospective study. DSC-MRI provides a corrected cerebral blood volume (cCBV), and DCE-MRI provides a volume transfer coefficient (Ktrans) for transfer from plasma to the extravascular extracellular space. Ktrans and cCBV were measured from a round region-of-interest in the slice of maximum size on the contrast-enhanced lesion. The differences in t values between CNSL and HGG for determining the most appropriate percentile of Ktrans and cCBV were investigated. The differences in Ktrans, cCBV, and Ktrans/cCBV between CNSL and HGG were investigated using histogram analysis. Receiver operating characteristic (ROC) analysis of Ktrans, cCBV, and Ktrans/cCBV ratio was performed. RESULTS: The 30th percentile (C30) in Ktrans and 80th percentile (C80) in cCBV were the most appropriate percentiles for distinguishing between CNSL and HGG from the differences in t values. CNSL showed significantly lower C80 cCBV, significantly higher C30 Ktrans, and significantly higher C30 Ktrans/C80 cCBV than those of HGG. In ROC analysis, C30 Ktrans/C80 cCBV had the best discriminative value for differentiating between CNSL and HGG as compared to C30 Ktrans or C80 cCBV. CONCLUSION: The combination of Ktrans by DCE-MRI and cCBV by DSC-MRI was found to reveal the characteristics of vascularity and permeability of a lesion more precisely than either Ktrans or cCBV alone. Histogram analysis of these vascular microenvironments enabled quantitative differentiation between CNSL and HGG.

BACKGROUND: Although a subdural fluid collection frequently is observed, diagnostic methods that differentiate between the subdural collection caused by external hydrocephalus and that caused by subdural hygroma have not been established. Here, we report a case of external hydrocephalus caused by Gliadel-induced eosinophilic meningitis that has been previously reported in only 1 case and can be diagnosed by time-spatial labeling inversion pulse magnetic resonance imaging (time-SLIP MRI). CASE DESCRIPTION: A tumor located in the left temporal was detected incidentally in an 81-year-old man by examination of a head injury. The tumor was surgically resected and diagnosed as a high-grade glioma during the surgery; Gliadel wafers subsequently were implanted. Three weeks after the resection, the patient showed disturbed consciousness, and computed tomography revealed a subdural fluid collection. The out-flow of cerebrospinal through the resection cavity was detected by time-SLIP MRI. Cerebrospinal tests indicated high white blood cell counts and high protein levels, with more than 90% of the white blood cell count comprising eosinophils. Therefore, we suspected that the subdural fluid collection was caused by external hydrocephalus because of Gliadel-induced eosinophilic meningitis. We surgically removed the Gliadel wafers and subsequently performed a surgery to insert a ventriculoperitoneal shunt. Histologic examination indicated eosinophilic accumulation around the Gliadel wafers. The patient's symptoms improved after the insertion of a ventriculoperitoneal shunt. CONCLUSIONS: In the present case, time-SLIP MRI was a useful and noninvasive method for diagnosing external hydrocephalus which was caused by eosinophilic meningitis because of Gliadel-induced eosinophilic meningitis.

Most IDH mutant gliomas harbor either 1p/19q co-deletions or TP53 mutation; 1p/19q co-deleted tumors have significantly better prognoses than tumors harboring TP53 mutations. To investigate the clinical factors that contribute to differences in tumor progression of IDH mutant gliomas, we classified recurrent tumor patterns based on MRI and correlated these patterns with their genomic characterization. Accordingly, in IDH mutant gliomas (N = 66), 1p/19 co-deleted gliomas only recurred locally, whereas TP53 mutant gliomas recurred both locally and in remote intracranial regions. In addition, diffuse tensor imaging suggested that remote intracranial recurrence in the astrocytomas, IDH-mutant with TP53 mutations may occur along major fiber bundles. Remotely recurrent tumors resulted in a higher mortality and significantly harbored an 8q gain; astrocytomas with an 8q gain resulted in significantly shorter overall survival than those without an 8q gain. OncoScan® arrays and next-generation sequencing revealed specific 8q regions (i.e., between 8q22 and 8q24) show a high copy number. In conclusion, only tumors with TP53 mutations showed patterns of remote recurrence in IDH mutant gliomas. Furthermore, an 8q gain was significantly associated with remote intracranial recurrence and can be considered a poor prognostic factor in astrocytomas, IDH-mutant.

Introduction: To visualize peripheral nerves in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), we used MR imaging. We also quantified the volumes of the brachial and lumbar plexus and their nerve roots. Methods: Thirteen patients with CIDP and 12 healthy volunteers were enrolled. Whole- body MR neurography based on diffusionweighted whole- body imaging with background body signal suppression ( DWIBS) was performed. Peripheral nerve volumes were calculated from serial axial MR images. Results: The peripheral nervous system was visualized with 3-dimensional reconstruction. Volumes ranged from 8.7 to 49.5 cm(3)/m(2) in the brachial plexus and nerve roots and from 10.2 to 53.5 cm(3)/m(2) in the lumbar plexus and nerve roots. Patients with CIDP had significantly larger volumes than controls ( P &lt; 0.05), and volume was positively correlated with disease duration. Conclusions: MR neurography and the measurement of peripheral nerve volume are useful for diagnosing and assessing CIDP.

Objective We aimed to clarify the cause of shortened mean transit time (MTT) in acute ischemic cerebrovascular disease and examined its relationship with reperfusion. Methods Twenty-three patients with acute ischemic cerebrovascular disease underwent whole-brain computed tomography perfusion (CTP). The maximum MTT (MTT max), minimum MTT (MTT min), ratio of maximum and minimum MTT (MTT min/max), and minimum cerebral blood volume (CBV) (CBV min) were measured by automatic region of interest analysis. Diffusion weighted image was performed to calculate infarction volume. We compared these CTP parameters between reperfusion and nonreperfusion groups and calculated correlation coefficients between the infarction core volume and CTP parameters. Results Significant differences were observed between reperfusion and nonreperfusion groups (MTT min/max: P = 0.014; CBV min ratio: P = 0.038). Regression analysis of CTP and high-intensity volume on diffusion weighted image showed negative correlation (CBV min ratio: r = -0.41; MTT min/max: r = -0.30; MTT min ratio: r = -0.27). Conclusions A region of shortened MTT indicated obstructed blood flow, which was attributed to the singular value decomposition method error.

Recent progress in neuro-oncology has validated the significance of genetic diagnosis in gliomas. We previously investigated IDH1/2 and TP53 mutations via Sanger sequencing for adult supratentorial gliomas and reported that PCR-based sequence analysis classified gliomas into three genetic subgroups that have a strong association with patient prognosis: IDH mutant gliomas without TP53 mutations, IDH and TP53 mutant gliomas, and IDH wild-type gliomas. Furthermore, this analysis had a strong association with patient prognosis. To predict genetic subgroups prior to initial surgery, we retrospectively investigated preoperative radiological data using CT and MRI, including MR spectroscopy (MRS), and evaluated positive 5-aminolevulinic acid (5-ALA) fluorescence as an intraoperative factor. We subsequently compared these factors to differentiate each genetic subgroup. Multiple factors such as age at diagnosis, tumor location, gadolinium enhancement, 5-ALA fluorescence, and several tumor metabolites according to MRS, such as myo-inositol (myo-inositol/total choline) or lipid20, were statistically significant factors for differentiating IDH mutant and wild-type, suggesting that these two subtypes have totally distinct characteristics. In contrast, only calcification, laterality, and lipid13 (lipid13/total Choline) were statistically significant parameters for differentiating TP53 wild-type and mutant in IDH mutant gliomas. In this study, we detected several pre- and intraoperative factors that enabled us to predict genetic subgroups for adult supratentorial gliomas and clarified that lipid13 quantified by MRS is the key tumor metabolite that differentiates TP53 wild-type and mutant in IDH mutant gliomas. These results suggested that each genetic subtype in gliomas selects the distinct lipid synthesis pathways in the process of tumorigenesis.

BACKGROUND: Glioblastoma with oligodendroglioma component (GBMO) is a subtype of conventional glioblastoma (cGBM), which is categorized as WHO grade IV. GBMO can be histopathologically distinguished from cGBM and the prognosis of GBMO is better than that of cGBM. However, no systematic review of GBMO imaging findings has been published to date. PURPOSE: To clarify the radiological imaging features of GBMO compared with those of cGBM. MATERIAL AND METHODS: The participants were 15 patients with GBMO and 32 patients with cGBM as a control group, all of whom were histopathologically diagnosed. A radiologist retrospectively reviewed the imaging findings of both computed tomography (CT) and magnetic resonance imaging (MRI) for density, signal intensity, contrast medium enhancement (CE), cortical swelling, and cortical swelling without CE. We statistically analyzed the imaging findings by Chi-squared test. RESULTS: Cortical swelling without CE in GBMO was significantly greater than that in cGBM (P = 0.004). Non-CE and heterogeneous solid enhancement were observed significantly more often in GBMO (P = 0.004). No other findings were significant. CONCLUSION: There was significant difference in the findings of the CE, which exhibited solid heterogeneous enhancement in GBMO. Cortical swelling without CE can be considered significantly characteristic of GBMO.

BACKGROUND: Spontaneous intracranial hypotension (SIH) due to cerebrospinal fluid (CSF) leakage at C1-2 poses diagnostic and therapeutic challenges to spine surgeons. Although computed tomography (CT) myelography has been the diagnostic imaging modality of choice for identifying the CSF leakage point, extradural CSF collection at C1-2 on conventional CT myelography or magnetic resonance imaging (MRI) may often be a false localizing sign. CASE DESCRIPTION: The present study reports the successful application of time-spatial labeling inversion pulse (T-SLIP) MRI, which enabled the precise identification of the CSF leakage point at C1-2 in a 28-year-old woman with intractable SIH. After identifying the leakage point using both CT myelography and T-SLIP MRI, surgery was performed to seal the CSF leak. Intraoperatively, a pouch suggestive of an extradural arachnoid cyst around the left C2 nerve root was found, which was repaired by packing the pouch with muscle and fibrin glue. Clinical improvement was observed shortly after surgery, and postoperative imaging revealed the disappearance of the CSF leakage. CONCLUSIONS: T-SLIP MRI may provide useful information on the flow dynamics of CSF in SIH patients due to high-flow leakage. However, further experience is required to assess its sensitivity and specificity as an imaging modality for identifying CSF leakage points.

Objective: We compared cerebral blood flow (CBF) measured using computed tomographic (CT) perfusion (CTP) and N-isopropyl-p-[(123) I]-iodoamphetamine cerebral perfusion single-photon emission computed tomography (SPECT). Methods: We used a 320-row area detector CT and N-isopropyl-p-[(123) I]-iodoamphetamine cerebral perfusion SPECT under similar conditions in patients with chronic cerebrovascular disease. Images were automatically aligned 3-dimensionally for voxel-by-voxel comparisons. Results: Linear positive correlations were observed between CTP-CBF including high-blood-flow areas and SPECT-CBF over the whole brain (r = 0.001-0.6, P &lt; 0.01), superior cerebral level (r = 0.45-0.93, P &lt; 0.01), basal ganglia level (r = 0.44-0.77, P &lt; 0.01), and skull base (r = 0.02-0.66, P &lt; 0.01). Correlations between CTP-CBF excluding high-blood-flow areas were significantly higher (P &lt; 0.0001). Conclusions: Computed tomographic perfusion overestimated CBF compared with SPECT and showed poor correlation at the skull base. Computed tomographic perfusion CTP excluding high-blood-flow areas improved the correlation over the whole brain in patients with chronic cerebrovascular disease.