ABSTRACT
Histopathological verification is currently required to differentiate tumor recurrence from treatment effects related to adjuvant therapy in patients with glioma. To bypass the complications associated with collecting neural tissue samples, non-invasive classification methods are needed to alleviate the burden on patients while providing vital information to clinicians. However, uncertainty remains as to which tissue features on magnetic resonance imaging (MRI) are useful. The primary objective of this study was to quantitatively assess the reliability of combining MRI and diffusion tensor imaging metrics to discriminate between tumor recurrence and treatment effects in histopathologically identified biopsy samples. Additionally, this study investigates the noise adjuvant radiation therapy introduces when discriminating between tissue types. In a sample of 41 biopsy specimens, from a total of 10 patients, we derived region-of-interest samples from MRI data in the ipsilateral hemisphere that encompassed biopsies obtained during resective surgery. This study compares normalized intensity values across histopathology classifications and contralesional volumes reflected across the midline. Radiation makes noninvasive differentiation of abnormal-nontumor tissue to tumor recurrence much more difficult. This is because radiation exhibits opposing behavior on key MRI modalities: specifically, on post-contrast T1, FLAIR, and GFA. While radiation makes noninvasive differentiation of tumor recurrence more difficult, using a novel analysis of combined MRI metrics combined with clinical annotation and histopathological correlation, we observed that it is possible to successfully differentiate tumor tissue from other tissue types. Additional work will be required to expand upon these findings.
ABSTRACT
In the treatment of brain tumors, surgical intervention remains a common and effective therapeutic option. Recent advances in neuroimaging have provided neurosurgeons with new tools to overcome the challenge of differentiating healthy tissue from tumor-infiltrated tissue, with the aim of increasing the likelihood of maximizing the extent of resection volume while minimizing injury to functionally important regions. Novel applications of diffusion tensor imaging (DTI), and DTI-derived tractography (DDT) have demonstrated that preoperative, non-invasive mapping of eloquent cortical regions and functionally relevant white matter tracts (WMT) is critical during surgical planning to reduce postoperative deficits, which can decrease quality of life and overall survival. In this review, we summarize the latest developments of applying DTI and tractography in the context of resective surgery and highlight its utility within each stage of the neurosurgical workflow: preoperative planning and intraoperative management to improve postoperative outcomes.
ABSTRACT
BACKGROUND: Drugs of abuse (DOA) are widely used in the United States and are ubiquitous at outdoor music festivals. Attendees at music festivals are at high-risk for novel psychoactive substance (NPS) use, which is becoming more prevalent worldwide. No U.S. studies have employed an qualitative approach to investigate the etiologies of both traditional DOA and NPS use amongst music festival attendees. OBJECTIVES: The objective of this study was to improve understanding of the knowledge, attitudes, beliefs, and practices of festival attendees using NPS and DOA. METHODS: We conducted semi-structured interviews of 171 attendees during the Sonic Bloom and Arise music festivals in Colorado in 2015 and 2016. Discrete variables were summarized with descriptive statistics. The anonymous, multi-domain interview documented the knowledge, attitudes beliefs, and practices underlying DOA use, which were analyzed with qualitative methods. RESULTS: We enrolled 171 participants that endorsed DOA use at the festivals. Most were experienced DOA users, who perceived minimal risks associated with DOA and NPS use. Nearly all unanimously reported normalization of DOA at music festivals. Participants popularly cited empathogenic, entactogenic, and entheogenic effects of DOA as their primary motivations for use. NPS use was endorsed by 39.8% (n = 68) of respondents, all of whom identified as being experienced DOA users. CONCLUSIONS: This population of novel psychoactive substance users is primarily composed of experienced drug users that endorsed use because of low cost, minimal perceived risk, accessibility, and normalization of drug use at music festivals.
