A case series on the role of 18F-FDG PET/CT-guided biopsy of osseous metastases.

PURPOSE: This case series explores the utility of positron emission tomography (PET)/computed tomography (CT) guidance for biopsy of 18F-fludeoxyglucose (FDG)-avid osseous lesions that are inconspicuous on CT. METHODS: PET/CT-guided core biopsies were performed in four patients with suspected malignancies given 18F-FDG-avid osseous lesions that were inconspicuous on CT alone. The final diagnosis for each patient was determined by histopathological and molecular testing. RESULTS: PET/CT-guided biopsy yielded accurate sampling via core needle biopsy (CNB) with histopathological confirmation of osseous metastases of the primary malignancy as opposed to a secondary malignancy in three patients and ruled-out metastatic spread in the fourth. CONCLUSION: PET/CT-guided biopsy of hypermetabolic osseous lesions that are inconspicuous on CT alone is an effective and safe diagnostic tool in patients with suspected malignancy.

Findings from Structural MR Imaging in Military Traumatic Brain Injury.

PURPOSE: To describe the initial neuroradiology findings in a cohort of military service members with primarily chronic mild traumatic brain injury (TBI) from blast by using an integrated magnetic resonance (MR) imaging protocol. MATERIALS AND METHODS: This study was approved by the Walter Reed National Military Medical Center institutional review board and is compliant with HIPAA guidelines. All participants were military service members or dependents recruited between August 2009 and August 2014. There were 834 participants with a history of TBI and 42 participants in a control group without TBI (not explicitly age- and sex-matched). MR examinations were performed at 3 T primarily with three-dimensional volume imaging at smaller than 1 mm(3) voxels for the structural portion of the examination. The structural portion of this examination, including T1-weighted, T2-weighted, before and after contrast agent administrtion T2 fluid attenuation inversion recovery, and susceptibility-weighted images, was evaluated by neuroradiologists by using a modified version of the neuroradiology TBI common data elements (CDEs). Incident odds ratios (ORs) between the TBI participants and a comparison group without TBI were calculated. RESULTS: The 834 participants were diagnosed with predominantly chronic (mean, 1381 days; median, 888 days after injury) and mild (92% [768 of 834]) TBI. Of these participants, 84.2% (688 of 817) reported one or more blast-related incident and 63.0% (515 of 817) reported loss of consciousness at the time of injury. The presence of white matter T2-weighted hyperintense areas was the most common pathologic finding, observed in 51.8% (432 of 834; OR, 1.75) of TBI participants. Cerebral microhemorrhages were observed in a small percentage of participants (7.2% [60 of 834]; OR, 6.64) and showed increased incidence with TBI severity (P < .001, moderate and severe vs mild). T2-weighted hyperintense areas and microhemorrhages did not collocate by visual inspection. Pituitary abnormalities were identified in a large proportion (29.0% [242 of 834]; OR, 16.8) of TBI participants. CONCLUSION: Blast-related injury and loss of consciousness is common in military TBI. Structural MR imaging demonstrates a high incidence of white matter T2-weighted hyperintense areas and pituitary abnormalities, with a low incidence of microhemorrhage in the chronic phase.

Restricted diffusion of the splenium in acute Wernicke's encephalopathy.

Acute Wernicke's encephalopathy (WE) is caused by profound vitamin B1 (thiamine) deficiency and commonly presents with the classic clinical triad of mental confusion, ataxia, and ophthalmoplegia. This characteristic presentation results from the propensity of acute thiamine deficiency to preferentially injure specific brain regions: the dorsomedial thalamus, periaqueductal gray, and mamillary bodies. In these regions, abnormal magnetic resonance signaling on conventional sequences has been well described; however, diffusion restriction has only recently been reported. The authors demonstrate diffusion-weighted imaging (DWI) abnormalities of the splenium of the corpus callosum in a patient with acute WE, which has not been reported previously, and suggest a potential pathological mechanism. With the recent addition of DWI, MRI is becoming more sensitive to the changes in acute WE. Furthermore, the use of apparent diffusion coefficient mapping to evaluate the extent of likely underlying cytotoxic injury may help determine long-term response to vitamin therapy and, thus, disability.