Recurrent Glioma: Does Qualitative Simultaneous 18F-DOPA PET/mp-MRI Improve Diagnostic Workup? An Initial Experience.

RATIONALE OF THE STUDY: Neuroimaging modalities such as contrast-enhanced MRI and PET provide significant insight in the evaluation of gliomas. However, their reliability in successfully differentiating the tumor recurrence with treatment-related changes is still technologically challenging. The current study aims to qualitatively investigate the potential of the hybrid PET/multiparametric MRI modality to noninvasively distinguish between these 2 outcomes of brain tumor diagnostics for optimum and early patient management. PATIENTS AND METHODS: A cohort of 26 suspected recurrent glioma cases proved on histology and/or clinicoradiological outcome forms the part of this study. A 3-point visual analytical scale was used to qualify lesions as recurrent or posttreatment radiation effects on PET, conventional MRI, dynamic susceptibility contrast-perfusion-weighted imaging, apparent diffusion coefficient, and the MR spectroscopy according to their level of suspicion. RESULTS: Of the 26 patients, 21 patients were classified as recurrence and 5 as radiation necrosis. Advanced MRI parameters (perfusion, diffusion, and spectroscopy) integrated with 18F-DOPA PET imaging resulted in superior diagnostic performance obtained on visual assessment with an accuracy of 95%, sensitivity of 96%, and specificity approaching up to 100% over individual modalities. CONCLUSIONS: The combination of multiple MR parameters evaluated together with 18F-DOPA PET offers an attractive approach to noninvasively distinguish true recurrence from radiation necrosis. However, further prospective studies with larger cohorts are warranted with additional neuropathological validations.

Potential for differentiation of glioma recurrence from radionecrosis using integrated 18F-fluoroethyl-L-tyrosine (FET) positron emission tomography/magnetic resonance imaging: A prospective evaluation.

PURPOSE: To assess the utility of 18F-fluoroethyl-L-tyrosine (FET) positron emission tomography/magnetic resonance imaging (PET/MRI) in distinguishing recurrence from radionecrosis. MATERIALS AND METHODS: Thirty-two patients (25 males, 7 females) of glioma who had already undergone surgery/chemoradiotherapy and had enhancing brain lesions suspicious of recurrence were evaluated using integrated 18F-FET PET/MRI, and followed up with histopathology or clinical follow-up and/or MRI/PET/MRI imaging. Manually drawn regions of interest over areas of maximal enhancement or FET uptake were used to calculate tumor to background ratios [TBRmax, TBRmean], choline: creatine ratio [Cho: Cr ratio], normalized relative cerebral blood volume [N rCBVmean] and apparent diffusion coefficient [ADCmean]. Correlations were evaluated using Pearson's coefficient. Accuracy of each parameter was calculated using independent t-test and receiver operator curve (ROC) analysis while utility of all four parameters together using multivariate analysis of variance (MANOVA) for differentiating recurrence vs. radionecrosis was evaluated. Positive histopathology and imaging/clinical follow up served as the gold standard. RESULTS: Twenty-four of the 32 patients were diagnosed with recurrent disease and 8 with radiation necrosis. Significant correlations were observed between TBRmaxand N rCBVmean (ρ =0.503; P = 0.003), TBRmean, and N rCBVmean (ρ =0.414; P = 0.018), TBRmaxand ADCmean (ρ = -0.52; P = 0.002), and TBRmeanand ADCmean(ρ = -0.518; P = 0.002). TBRmax, TBRmean, ADCmean, Cho: Cr ratios, and N rCBVmeanwere significant in differentiating recurrence from radiation necrosis with an accuracy of 94.1%, 88.2%, 80.4%, 96.4%, and 89.9%, respectively. MANOVA indicated that combination of all parameters demonstrated better evaluation of recurrence vs. necrosis than any single parameter. The diagnostic accuracy, sensitivity, and specificity using all MRI parameters were 93.75%, 96%, and 85.7%, and using all FET PET/MRI parameters was 96.87%, 100%, and 85.7%, respectively. CONCLUSIONS: Synergetic effect of multiple MR parameters evaluated together in addition to FET PET uptake highlights the fact that integrated 18F-FET PET/MRI might have the potential to impact management of patients with glioma by timely and conclusive recognition of true recurrence from radiation necrosis.

Use of hyperbaric oxygen in traumatic brain injury: retrospective analysis of data of 20 patients treated at a tertiary care centre.

Traumatic brain injury (TBI) related impact results in a permanent need for help in performing daily activities. Standard treatment consists of removing the cause, restore perfusion, support metabolic requirement and limit inflammatory and oxidative damage. Hyperbaric oxygen therapy (HBOT) is one such newer promising treatment that enhances neurological recovery to some extent. HBOT is intermittent inhalation of 100% oxygen at greater than normal atmospheric pressure and is internationally accepted for its role in well-defined indications. It is hypothesised that HBO has a role in reviving 'idling neurons', also called the ischemic penumbra defined as area of reduced cerebral blood flow, abolished synaptic activity but preserved structural integrity. We carried out a retrospective analysis of medical records of 20 patients of TBI who had been treated with HBOT in addition to standard management. These were placed in Group A (test group) and received at least 30 sessions of HBO along with standard treatment. The patients were assessed along the Disability Rating Scale (DRS), Glasgow coma scale (GCS) and Rancho Los Amigos Scale (RLAS). Another 20 patients of TBI, matched in age and severity of brain injury, who received standard treatment but not HBOT, were selected as the control group (Group B). Assessment on the DRS showed maximum improvement in patients with scores of 22-24 (vegetative state).The percentage of patients in the test group fell from 45% to 5% whereas only 20% patients in Group B had similar progress. After the treatment, a significantly higher proportion of HBOT treated subjects showed a good response in cognitive functions, as measured by RLA. In group A, 90% patients had a score of ≤ 3 and in Group B 95% had a similar score, which improved to ≥ 3 in 60% patients versus 30% patients respectively. In both groups maximum patients are in 1-6 months post-injury category and within the groups this category showed the greatest recovery, with a greater improvement in the test group as compared to control group.