Amino Acid Tracer PET MRI in Glioma Management: What a Neuroradiologist Needs to Know.

PET with amino acid tracers provides additional insight beyond MR imaging into the biology of gliomas that can be used for initial diagnosis, delineation of tumor margins, planning of surgical and radiation therapy, assessment of residual tumor, and evaluation of posttreatment response. Hybrid PET MR imaging allows the simultaneous acquisition of various PET and MR imaging parameters in a single investigation with reduced scanning time and improved anatomic localization. This review aimed to provide neuroradiologists with a concise overview of the various amino acid tracers and a practical understanding of the clinical applications of amino acid PET MR imaging in glioma management. Future perspectives in newer advances, novel radiotracers, radiomics, and cost-effectiveness are also outlined.

Intraosseous hemangioma of the clivus: a case report and review of the literature.

Intraosseous hemangiomas are benign vascular tumors that are encountered most commonly in vertebrae and rarely in the skull. When presenting in the skull, they are commonly found in the calvarium in frontal and parietal bones and seldom in the skull base. We encountered a patient with an incidental finding on magnetic resonance imaging (MRI) of an enhancing lesion in the clivus. Here we report an unusual location of a clival intraosseous hemangioma. A 62 year old man worked up for carpal tunnel syndrome had imaging of his cervical spine that revealed an enhancing clival lesion, which extended into the left occipital condyle. Endoscopic endonasal biopsy was performed on the abnormality revealing a capillary hemangioma. Patient tolerated the biopsy well and no further surgical intervention is indicated at this time. Patient will be followed at six month intervals. Primary intraosseus hemangiomas of the skull are extremely rare and usually occur in the calvarium. This is one of the few reported case of an intraosseus hemangioma in the clivus. We present this case in part because it is unusual, but more importantly, with the wider use of MRI, it is likely that these lesions will be discovered more frequently, and conceivably confused for more dangerous lesions.

Percentage signal recovery derived from MR dynamic susceptibility contrast imaging is useful to differentiate common enhancing malignant lesions of the brain.

BACKGROUND AND PURPOSE: Differentiation of enhancing malignant lesions on conventional MR imaging can be difficult and various newer imaging techniques have been suggested. Our aim was to evaluate the role of PSR obtained from DSC perfusion measurements in differentiating lymphoma, GBM, and metastases. The effectiveness of PSR was compared with that of rCBV. We hypothesized that the newly defined parameter of PSR is more sensitive and specific in differentiating these lesions. MATERIALS AND METHODS: This retrospective study included 66 patients (39 men and 27 women; age range: 27-82 years) with a pathologically proved diagnosis of primary CNS lymphoma, GBM, or metastases (22 patients in each group). Mean PSR, min PSR, max PSR, and rCBV were calculated. The classification accuracy of these parameters was investigated by using ROC. RESULTS: Mean PSR was high (113.15 ± 41.59) in lymphoma, intermediate in GBM (78.22 ± 14.27), and low in metastases (53.46 ± 12.87) with a P value < .000. F values obtained from 1-way ANOVA analysis for mean, min, and max PSR ratios were 29.9, 39.4, and 23.4, respectively, which were better than those of rCBV (11.1) in differentiating the 3 groups. Max PSR yielded the best ROC characteristics with an A(z) of 0.934 (95% CI, 0.877-0.99) in differentiating lymphoma from metastases and GBM. The A(z) for mean and min PSR of 0.938 (95% CI, 0.0.884-0.990) and 0.938 (95% CI, 0.884-0.991), respectively, was better than rCBV (A(z), 0.534; 95% CI, 0.391-0.676) in the differentiation of metastases from GBM and lymphoma (P ≤ .0001). CONCLUSIONS: PSR appears to be a parameter that helps in differentiating intracerebral malignant lesions such as GBM, metastases, and lymphoma.