Prediction of survival in patients affected by glioblastoma: histogram analysis of perfusion MRI.

PURPOSE: The identification of prognostic biomarkers plays a pivotal role in the management of glioblastoma. The aim of this study was to assess the role of magnetic resonance dynamic susceptibility contrast imaging (DSC-MRI) with histogram analysis in the prognostic evaluation of patients suffering from glioblastoma. MATERIALS AND METHODS: Sixty-eight patients with newly diagnosed pathologically verified GBM were retrospectively evaluated. All patients underwent MRI investigations, including DSC-MRI, surgical procedure and received postoperative focal radiotherapy plus daily temozolomide (TMZ), followed by adjuvant TMZ therapy. Relative cerebral blood volume (rCBV) histograms were generated from a volume of interest covering the solid portions of the tumor and statistically evaluated for kurtosis, skewness, mean, median and maximum value of rCBV. To verify if histogram parameters could predict survival at 1 and 2 years, receiver operating characteristic (ROC) curves were obtained. Kaplan-Meier method was used to calculate patient's overall survival. RESULTS: rCBV kurtosis and rCBV skewness showed significant differences between subjects surviving > 1 and > 2 years, According to ROC analysis, the rCBV kurtosis showed the best statistic performance compared to the other parameters; respectively, values of 1 and 2.45 represented an optimised cut-off point to distinguish subjects surviving over 1 or 2 years. Kaplan-Meier curves showed a significant difference between subjects with rCBV kurtosis values higher or lower than 1 (respectively 1021 and 576 days; Log-rank test: p = 0.007), and between subjects with rCBV kurtosis values higher or lower than 2.45 (respectively 802 and 408 days; Log-rank test: p = 0.001). CONCLUSION: The histogram analysis of perfusion MRI proved to be a valid method to predict survival in patients affected by glioblastoma.

Predictive role of dynamic contrast enhanced T1-weighted MR sequences in pre-surgical evaluation of macroadenomas consistency.

PURPOSE: Our hypothesis was that pituitary macroadenomas show different areas of consistency detectable by enhanced magnetic resonance imaging (MRI) with Dynamic study during gadolinium administration. MATERIALS AND METHODS: We analysed 21 patients with pituitary macroadenomas between June 2013 and June 2015. All patients underwent trans-sphenoidal surgery and neurosurgeon described macroadenomas consistency. Similarly, two neuroradiologists manually drew regions of interest (ROIs) inside the solid-appearing portions of macroadenoma and in the normal white matter both on dynamic and post-contrast acquisitions. The ratio between these ROIs, defined as Signal Intensity Ratio (SIR), allowed obtaining signal intensity curves over time on dynamic acquisition and a single value on post-contrast MRI. SIR values best differentiating solid from soft macroadenoma components were calculated and correlated with pathologic patterns. A two-sample T test and empiric receiver operating characteristic (ROC) curve of SIR was performed. RESULTS: According to ROC analysis, the SIR value of 1.92, obtained by dynamic acquisition, best distinguished soft and hard components. All the specimens from soft components were characterized by high cellularity, high representation of vascularization and micro-haemorrhage and low percentage of collagen content. The reverse was evident in hard components. CONCLUSIONS: We demonstrated that dynamic MRI acquisition could distinguish with good accuracy macroadenomas consistency.

Accuracy of F-DOPA PET and perfusion-MRI for differentiating radionecrotic from progressive brain metastases after radiosurgery.

PURPOSE: We assessed the performance of 6-[(18)F]-fluoro-L-3,4-dihydroxyphenylalanine (F-DOPA) PET for differentiating radionecrosis (RN) from tumour progression (PD) in a population of patients with brain metastases, treated with stereotactic radiosurgery. The accuracy of F-DOPA PET was compared with that of perfusion-weighted magnetic resonance (perfusion-MR). METHODS: In 42 patients with a total of 50 brain metastases from various primaries F-DOPA PET/CT was performed because of suspected radiological progression at the site of previously irradiated brain metastasis. Several semiquantitative PET parameters were recorded, and their diagnostic accuracy was compared by receiver operating characteristic curve analyses. The diagnosis was established by either surgery or follow-up. A comparison was made between F-DOPA PET and perfusion-MR sequences acquired no more than 3 weeks apart. RESULTS: Definitive outcome was available in 46 of the 50 lesions (20 PD, 26 RN). Of the 46 lesions, 11 were surgically excised while in the remaining 35 lesions the diagnosis was established by radiological and clinical criteria. The best diagnostic performance was obtained using the semiquantitative PET parameter maximum lesion to maximum background uptake ratio (SUVLmax/Bkgrmax). With a cut-off value of 1.59, a sensitivity of 90 % and a specificity of 92.3 % were achieved in differentiating RN from PD lesions (accuracy 91.3 %). Relative cerebral blood volume (rCBV) derived from perfusion-MR was available for comparison in 37 of the 46 metastases. Overall accuracy of rCBV was lower than that of all semiquantitative PET parameters under study. The best differentiating rCBV cut-off value was 2.14; this yielded a sensitivity of 86.7 % and a specificity of 68.2 % (accuracy 75.6 %). CONCLUSION: F-DOPA PET is a highly accurate tool for differentiating RN from PD brain metastases after stereotactic radiosurgery. In this specific setting, F-DOPA PET seems to perform better than perfusion-MR.

Role of multidetector CT in the recognition of hyperdense middle cerebral artery sign (HMCAS) in patients with acute cerebral ischaemia: correlation with DWI-MRI sequences and clinical data.

PURPOSE: The aim of this study was to verify the sensitivity and specificity of the hyperdense middle cerebral artery sign (HMCAS) obtained by multidetector computed tomography (CT) in predicting acute stroke, using diffusion-weighted (DW) magnetic resonance imaging (MRI) as a reference. The location of the HMCAS, the extension of the ischaemic lesion and its prognostic value were also assessed. MATERIALS AND METHODS: The CT examinations of 654 patients with symptoms related to acute cerebral stroke were retrospectively reviewed. DW-MRI confirmed recent stroke in 175 patients. Two expert neuroradiologists analysed the CT examinations of these patients in four phases. Sensitivity, specificity and interobserver reliability was evaluated. Patients were divided into three groups according to the HMCAS site (M1-M2-M3) and the Alberta Stroke Program Early CT Score (ASPECTS) on DW-MRI was calculated. The ASPECTS average score was correlated with the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) at 3 months. RESULTS: In 41 patients, the presence of HMCAS was confirmed (71 % sensitivity; 100 % specificity; Interobserver reliability k, 84 %). An inverse correlation was found by comparing the ASPECTS and NIHSS scores (Rsq = -0.206). After logistic regression analysis, HMCAS was found to be independently associated with a poor outcome (mRS >2) at 3 months after adjusting for age, NIHSS on admission, risk factors and aetiology of stroke. CONCLUSIONS: Our study demonstrated that HMCAS obtained with multidetector CT can be detected in more than 70 % of patients with large acute ischaemic lesion and it is an unfavourable prognostic sign.

Asymmetric posterior reversible encephalopathy syndrome in patient with hyperplastic anterior choroidal artery.

We describe a case of asymmetric PRES due to the presence of hyperplastic anterior choroidal artery (AChA) in a man affected by sever hypertension. Posterior reversible encephalopathy syndrome (PRES) has become synonymous with a unique pattern of brain vasogenic edema and predominates in the parietal and occipital regions, accompanied by clinical neurological alterations. Sever hypertension is a risk factor that exceeds the limits of brain autoregulation, leading to breakthrough brain edema. In our knowledge this is the first case reported in literature, in which a similar vascular abnormality is linked to a PRES syndrome.

Diffuse axonal injury with selective involvement of the corticospinal tract. A diffusion tensor imaging case study.

The identification of diffuse axonal injury (DAI) can be difficult, especially using conventional imaging (CT or MRI), which usually appears normal. Diffusion tensor imaging (DTI) is useful in identifying white matter abnormalities in patients with DAI. We describe the case of a 17-year-old female with severe closed head injury and right-side hemiparesis, studied with DTI and MR-tractography. In this case, DTI was useful to detect focal and diffuse signs of DAI.