Glioblastoma multiforme regional genetic and cellular expression patterns: influence on anatomic and physiologic MR imaging.

PURPOSE: To determine whether magnetic resonance (MR) imaging is influenced by genetic and cellular features of glioblastoma multiforme (GBM) aggressiveness. MATERIALS AND METHODS: In this HIPAA-compliant institutional review board-approved study, multiple enhancing and peritumoral nonenhancing stereotactic neurosurgical biopsy samples from treatment-naïve GBMs were collected prospectively, with guidance from cerebral blood volume (CBV) MR imaging measurements. By using monoclonal antibodies, tissue specimens were examined for microvascular expression, hypoxia, tumor and overall cellular density, and histopathologic features of GBM aggressiveness. Genetic expression patterns were investigated with RNA microarrays. Imaging and histopathologic variables were compared with the Welch t test and Pearson correlations. Microarray analysis was performed by using false discovery rate (FDR) statistics. RESULTS: Tumor biopsy of 13 adult patients yielded 16 enhancing and 14 peritumoral nonenhancing specimens. Enhancing regions had elevated relative CBV and reduced relative apparent diffusion coefficient (ADC) measurements compared with peritumoral nonenhancing biopsy regions (P < .01). A positive correlation was found between relative CBV and all histopathologic features of aggressiveness (P < .04). An inverse correlation was found between relative ADC and all histopathologic features of aggressiveness (P < .05). RNA expression patterns between tumor regions were found to be significantly different (FDR < 0.05), with hierarchical clustering by biopsy region only. CONCLUSION: These findings suggest MR imaging is significantly influenced by GBM genetic and cellular biologic features of aggressiveness and imply physiologic MR imaging may be useful in pinpointing regions of highest malignancy within heterogeneous tissues, thus facilitating histologic grading of primary glial brain tumors.

Differentiation of recurrent glioblastoma multiforme from radiation necrosis after external beam radiation therapy with dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging.

PURPOSE: To investigate whether cerebral blood volume (CBV), peak height (PH), and percentage of signal intensity recovery (PSR) measurements derived from the results of T2-weighted dynamic susceptibility-weighted contrast material-enhanced (DSC) magnetic resonance (MR) imaging performed after external beam radiation therapy (EBRT) can be used to distinguish recurrent glioblastoma multiforme (GBM) from radiation necrosis. MATERIALS AND METHODS: Fifty-seven patients were enrolled in this HIPAA-compliant institutional review board-approved retrospective study after they received a diagnosis of GBM, underwent EBRT, and were examined with DSC MR imaging, which revealed progressive contrast enhancement within the radiation field. A definitive diagnosis was established at subsequent surgical resection or clinicoradiologic follow-up. Regions of interest were retrospectively drawn around the entire contrast-enhanced region. This created T2-weighted signal intensity-time curves that produced three cerebral hemodynamic MR imaging measurements: CBV, PH, and PSR. Welch t tests were used to compare measurements between groups. RESULTS: Mean, maximum, and minimum relative PH and relative CBV were significantly higher (P < .01) in patients with recurrent GBM than in patients with radiation necrosis. Mean, maximum, and minimum relative PSR values were significantly lower (P < .05) in patients with recurrent GBM than in patients with radiation necrosis. CONCLUSION: These findings suggest that DSC perfusion MR imaging may be used to differentiate recurrent GBM from EBRT-induced radiation necrosis.

Opioid pharmacovigilance: A clinical-social history of the changes in opioid prescribing for patients with co-occurring chronic non-cancer pain and substance use.

There is growing concern among US-based clinicians, patients, policy makers, and in the media about the personal and community health risks associated with opioids. Perceptions about the efficacy and appropriateness of opioids for the management of chronic non-cancer pain (CNCP) have dramatically transformed in recent decades. Yet, there is very little social scientific research identifying the factors that have informed this transformation from the perspectives of prescribing clinicians. As part of an on-going ethnographic study of CNCP management among clinicians and their patients with co-occurring substance use, we interviewed 23 primary care clinicians who practice in safety-net clinical settings. In this paper, we describe the clinical and social influences informing three historic periods: (1) the escalation of opioid prescriptions for CNCP; (2) an interim period in which the efficacy of and risks associated with opioids were re-assessed; and (3) the current period of "opioid pharmacovigilance," characterized by the increased surveillance of opioid prescriptions. Clinicians reported that interpretations of the evidence-base in favor of and opposing opioid prescribing for CNCP evolved within a larger clinical-social context. Historically, pharmaceutical marketing efforts and clinicians' concerns about racialized healthcare disparities in pain treatment influenced opioid prescription decision-making. Clinicians emphasized how patients' medical complexity (e.g. multiple chronic health conditions) and structural vulnerability (e.g. poverty, community violence) impacted access to opioids within resource-limited healthcare settings. This clinical-social history of opioid prescribing practices helps to elucidate the ongoing challenges of CNCP treatment in the US healthcare safety net and lends needed specificity to the broader, nationwide conversation about opioids.