SUMMARY:The current standard of care for newly diagnosed cases of high-grade glioma is surgical resection followed by RT with concurrent chemotherapy. The most widely used criteria for assessing treatment response are based on a 2D measurement of the enhancing area on MR imaging known as the Macdonald Criteria. Recently, nontumoral increases (pseudoprogression) and decreases (pseudoresponse) in enhancement have been found, and these can confuse outcome evaluation. Here we review pseudoprogression and pseudoresponse and describe how better understanding of these phenomena can aid interpretation.ABBREVIATIONS: ADC ϭ apparent diffusion coefficient; BBB ϭ blood-brain barrier; Cho ϭ choline; DSC ϭ dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging; DTI ϭ diffusion tensor imaging; DWI ϭ diffusion-weighted imaging; FDG ϭ fluorodeoxyglucose; FLAIR ϭ fluidattenuated inversion recovery; GBM ϭ glioblastoma multiforme; MGMT ϭ methyltransferase; NAA ϭ N-acetylaspartate; PET ϭ positron-emission tomography; PSR ϭ percentage of signalintensity recovery; RANO ϭ Response Assessment in Neuro-Oncology; rCBV ϭ relative cerebral blood volume; RECIST ϭ Response Evaluation Criteria in Solid Tumors; ROC ϭ receiver operating characteristic analysis; RT ϭ radiation therapy; TMZ ϭ temozolomide; VEGF ϭ vascular endothelial growth factor G BM is the most common primary malignant type of brain neoplasm in adults and is associated with a dismal prognosis. The current standard of care is surgical resection followed by RT and concomitant and adjuvant TMZ chemotherapy. This is a relatively recent standard, with pivotal data published in 2005, and it represents a milestone, because this approach has been shown to prolong the overall survival of these patients.1 With the standardization of treatment around surgery/RT/TMZ, certain patterns are beginning to emerge that were not previously noticed. In addition, in May 2009, the US Food and Drug Administration approved bevacizumab for recurrent glioblastoma. This anti-VEGF agent also can have a marked pattern of change on MR imaging. In addition to impacting individual patient care, these changes have also had an impact on clinical trials of new therapies. Macdonald CriteriaThe Macdonald Criteria 2 are currently the most widely used guideline for assessing response to therapy in patients with highgrade gliomas. These are based on 2D tumor measurements made in MR imaging scans, in conjunction with clinical assessment and corticosteroid dose. According to the Macdonald Criteria, tumor progression is considered to have occurred when an increase of Ͼ25% in the size of the contrast-enhancing lesion is observed. There are important limitations to these criteria, which only address the contrast-enhancing component of the tumor, and various updated guidelines for RANO have been published.3,4 As radiologists learn early in their training, contrast enhancement in posttreatment brain tumors is nonspecific and may not always be considered a true surrogate of tumor response.The limitations of th...

BACKGROUND AND PURPOSE:The T2-weighted gradient-echo (GRE) imaging is currently the gold standard MR imaging sequence for the evaluation of patients with cerebral cavernous malformation (CCM) lesions. We aimed to compare the sensitivity of susceptibility-weighted imaging (SWI) with T2-weighted fast spin-echo (FSE) and GRE imaging in assigning the number of CCM lesions in patients with the familial form of the disease.

Diffusion tensor imaging is a promising technique for the evaluation of patients with probable mild cognitive impairment. Early detection of the disease expands the treatment options, increasing the likelihood of a good clinical response and enhancing the quality of life of patients and their relatives. Further studies with larger populations are needed to confirm the role of diffusion tensor imaging in the evaluation of memory impairment.

Purpose To describe the occurrence of imaging-depicted sports-related stress injuries, fractures, and muscle and tendon disorders during the 2016 Summer Olympic Games in Rio de Janeiro, Brazil. Materials and Methods Data on radiologic examinations were collected and retrospectively analyzed centrally by two board-certified musculoskeletal radiologists (with a third musculoskeletal radiologist acting as an adjudicator in case of discrepancies). Descriptive data on all imaging examinations by using radiography, ultrasonography (US), and magnetic resonance (MR) imaging were collected and analyzed according to imaging modality, country of origin of the athletes, type of sport, and type and location of injury. Results There were 1101 injuries that occurred in 11 274 (9.8%) athletes. A total of 1015 radiologic examinations were performed, including 304 (30.0%) radiographic, 104 (10.2%) US, and 607 (59.8%) MR examinations. Excluding 10 athletes categorized as refugees, athletes from Africa had the highest utilization rate (14.8%, 148 of 1001). Athletes from Europe underwent the most examinations with 103 radiographic, 39 US, and 254 MR examinations. Gymnastics (artistic) had the highest percentage of athletes who underwent imaging (15.5%, 30 of 194). Athletics (track and field) had the most examinations (293, including 53 radiographic, 50 US, and 190 MR examinations). Conclusion The overall occurrence of imaging used to help diagnose sports-related injuries at the Rio de Janeiro 2016 Summer Olympics was 6.4% of athletes. In these cases, MR imaging comprised 60% of imaging utilization. RSNA, 2018 Online supplemental material is available for this article.

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