Post-embolisation susceptibility changes in giant meningiomas: multiparametric histogram analysis using non-contrast-enhanced susceptibility-weighted PRESTO, diffusion-weighted and perfusion-weighted imaging.

PURPOSE: To investigate imaging characteristics of post-embolised meningioma and to determine if SW imaging can delineate tumour ischaemia. MATERIALS AND METHODS: Sixteen patients were studied before and after preoperative embolisation therapy (8 histopathologically determined with ischaemia, 8 with non-ischaemia). In each patient, a slice-wise ROI for the entire tumour was established, and histogram variables (mean, SD, minimum, maximum, histogram width, mode, and peak height) of SW, ADC, CBV, CBF, MTT, and TTP maps were compared between ischaemic and non-ischaemic groups. Changes in SW histogram were correlated with histopathological characteristics. RESULTS: Signal intensity on the SW map tended to decrease in the ischaemic group and partially increased in the non-ischaemic group. A similar trend was observed on the ADC map. The PW histogram showed an MTT increase in ischaemic group; however, CBV did not show significant changes between ischaemic and non-ischaemic groups. Microhaemorrhage was slightly correlated with Δpeak height in the SW histogram. CONCLUSION: Post-embolisation changes of intrinsic T2-weighted MR contrasts on SW map are most likely associated with alterations in deoxyhaemoglobin levels and arterial blood flow.

Adapted focal experimental autoimmune encephalomyelitis to allow MRI exploration of multiple sclerosis features.

We aimed to determine an optimal protocol for inducing a focal inflammatory lesion within the rat brain that could be large enough for an easier MRI monitoring while still relevant as a multiple sclerosis (MS) like lesion. We adapted a two-hit model based on pre-sensitization of the Lewis rat with myelin oligodendrocyte protein (MOG) followed by stereotaxic injection of pro-inflammatory cytokines (TNFα+IFNγ) within the internal capsule. We compared the following two strategies to increase focal lesion development for an easier MR translation: (1) a higher sensitization step (MOG50) or (2) a higher cytokine step with lower sensitization (MOG25). Control animals were administered only cytokines without MOG pre-sensitization. Animals were followed with T2, diffusion and T1 post gadolinium weighted images at 1, 3 and 7days following cytokine injection. Immunostaining was performed at the same time points for macrophages (ED1), myelin (MBP and Luxol Fast Blue) and blood brain barrier integrity (IgG). At day 1, the focal lesions depicted with T2-weighted images were very similar among groups and related to vasogenic edema (high apparent diffusion coefficient (ADC), gadolinium enhancement and IgG extravasation) induced by cytokines irrespective of the pre-sensitization step. Then, at day 3, MOG50 rats developed statistically larger T2 lesions than MOG25 and control rats that were correlated with inflammatory cell accumulation. At day 7, MOG50 rats also showed larger T2 lesions than MOG25 and control rats, together with loss of anisotropy that were correlated with demyelination. In contrast, MOG25 and control rats developed similar MR lesions decreasing over time and almost undetectable at day 7. We conclude that with a high pre-sensitization step, the focal lesion can be monitored by MRI whose signal reflects some features of a MS-like lesion, i.e. edema, inflammatory cell accumulation and later demyelination.

Differentiating benign notochordal cell tumors from chordomas: radiographic features on MRI, CT, and tomography.

OBJECTIVE: The purpose of this study was to characterize the imaging spectrum of benign notochordal cell tumors (BNCTs) and chondromas and to determine if this helped in differentiating BNCTs from chordomas. MATERIALS AND METHODS: Thirty-eight patients pathologically diagnosed with chordomas were reviewed and ultimately diagnosed to have five BNCTs and 33 chordomas. The following radiologic findings were reevaluated by two radiologists by consensus: extraosseous extension, osseous change on CT or conventional tomography, T2-weighted MR signal intensity, T2-weighted signal homogeneity, and contrast-enhanced T1-weighted MR signal intensity. Fisher's exact test was performed to determine statistical significance. RESULTS: Our study yielded five results. First, four of five BNCTs (80%) were intraosseous, whereas 31 of 33 chordomas (94%) were both intra- and extraosseous (p < 0.0001). Second, all BNCTs showed mild osteosclerosis without bone destruction; all chordomas showed variable osteolysis (p = 0.0092). Third, all BNCTs and 28 of 33 chordomas (85%) showed hyperintensity on T2-weighted images (p > 0.05). Fourth, four of five BNCTs (80%) and 27 of 33 chordomas (82%) were heterogeneous on T2-weighted images (p > 0.05). Fifth, no BNCTs enhanced, whereas all chordomas variably enhanced (p < 0.0001). CONCLUSION: Radiologic studies may allow distinction of BNCTs from chordomas.

[Significance of postmortem computed tomography in forensic autopsy and its possible issues].

Postmortem imaging (PMI) including computed tomography (CT) and magnetic resonance imaging (MRI) has become a familiar procedure in forensic casework. We investigated a short term impact of postmortem CT(PM-CT) in routine forensic autopsy cases at our institute during a period of 9 months (n = 121, fetus--92 year-old, 7 h--years postmortem), comparing to autopsy findings. In identification, PM-CT was useful for matching skeletal/dental characteristics, superimposing, and detection of foreign materials. However, conventional X-ray was often more effective for detection of small metallic foreign bodies. In pathomorphology, PM-CT partly demonstrated important findings for determining the immediate cause of death, which were confirmed by autopsy, but interpretation to the underlying/initiating/preceding causes of death or contributory factor(s) was mostly difficult or impossible. However, accumulated PM-CT data were useful for retrospective evaluation and review of autopsy findings. These experiences indicate that PMI is useful for radiographic screening and documentation, to be included in supplementary procedures, employing knowledge and experiences of forensic autopsy.

CNS complications of hematopoietic stem cell transplantation.

OBJECTIVE: With the worldwide increase in the use of hematopoietic stem cell transplantation (HSCT), a high level of diligence is required for radiologists to understand HSCT-related complications in the CNS. This article describes the clinical background of HSCT and complications that occur in a time-dependent manner through the course of HSCT and addresses pivotal issues in diagnostic imaging. CONCLUSION: Acknowledging the realm of imaging manifestations and the underlying mechanism of HSCT will enhance diagnostic accuracy and optimize treatment decisions.

A single institutional subset analysis of the WJLCG study comparing concurrent and sequential chemoradiotherapy for stage III non-small-cell lung cancer.

PURPOSE: To supplement findings of the West Japan Lung Cancer Group (WJLCG) study, treatment outcomes in our institution were reviewed from the perspective of radiation oncology. MATERIALS AND METHODS: Chemotherapy consisted of cisplatin (80 mg/m2 on days 1 and 29), vindesine (3 mg/m2 on days 1, 8, 29, and 36), and mitomycin (8 mg/m2 on days 1 and 29). In the concurrent arm, radiation therapy began on day 2 with a dose of 56 Gy in 28 fractions over 6.8 weeks, with an interval of 10 days at 28 Gy. In the sequential arm, radiation therapy began on day 50 with a dose of 56 Gy in 28 fractions over 5.6 weeks, without an interval. RESULTS: Twenty-four patients in the concurrent arm and 25 patients in the sequential arm in our institution were eligible for the WJLCG study. In the concurrent arm, three patients could not receive the full dose of radiation therapy and 12 patients required interruption of radiation therapy for more than 4 days. The median survival time among per-protocol patients and in those with interruption or with incomplete radiation therapy was 28.9 months and 14.1 months, respectively (p = 0.02). In the sequential arm, one patient could not receive the full dose of radiation therapy and none of the patients required such interruption. Local relapse and distant metastases as the first site of relapse occurred in 12 (11 in-field, 1 marginal) and five patients, respectively, in the concurrent arm, and in eight (7 in-field, 1 marginal) and 11 patients, respectively, in the sequential arm. CONCLUSION: In the concurrent regimen, noncompletion or interruption of radiation therapy was frequent, and the prognosis of such patients was poor.