In-Phase and Opposed-Phase Imaging: Applications of Chemical Shift and Magnetic Susceptibility in the Chest and Abdomen.

An earlier incorrect version appeared online. This article was corrected on December 17, 2018.

Multimodality Review of Amyloid-related Diseases of the Central Nervous System.

Amyloid-ß (Aß) is ubiquitous in the central nervous system (CNS), but pathologic accumulation of Aß results in four distinct neurologic disorders that affect middle-aged and elderly adults, with diverse clinical presentations ranging from chronic debilitating dementia to acute life-threatening intracranial hemorrhage. The characteristic imaging patterns of Aß-related CNS diseases reflect the pathophysiology of Aß deposition in the CNS. Aß is recognized as a key component in the neuronal damage that characterizes the pathophysiology of Alzheimer disease, the most common form of dementia. Targeted molecular imaging shows pathologic accumulation of Aß and tau protein, and fluorine 18 fluorodeoxyglucose positron emission tomography and anatomic imaging allow differentiation of typical patterns of neuronal dysfunction and loss in patients with Alzheimer disease from those seen in patients with other types of dementia. Cerebral amyloid angiopathy (CAA) is an important cause of cognitive impairment and spontaneous intracerebral hemorrhage in the elderly. Hemorrhage and white matter injury seen at imaging reflect vascular damage caused by the accumulation of Aß in vessel walls. The rare forms of inflammatory angiopathy attributed to Aß, Aß-related angiitis and CAA-related inflammation, cause debilitating neurologic symptoms that improve with corticosteroid therapy. Imaging shows marked subcortical and cortical inflammation due to perivascular inflammation, which is incited by vascular Aß accumulation. In the rarest of the four disorders, cerebral amyloidoma, the macroscopic accumulation of Aß mimics the imaging appearance of tumors. Knowledge of the imaging patterns and pathophysiology is essential for accurate diagnosis of Aß-related diseases of the CNS. (©)RSNA, 2016.

Utility of CT angiography in screening for traumatic cerebrovascular injury.

OBJECTIVE: Computed tomographic angiography (CTA) is increasingly utilized to evaluate for traumatic cerebrovascular injury (TCVI). The purpose of this study was to determine the yield, management effect, and risk of stroke or poor outcome of a positive CTA in a large cohort of trauma patients. PATIENTS AND METHODS: A retrospective analysis was performed on 1290 consecutive trauma patients that underwent head and/or neck CTA at our level I trauma center from 2006 to 2015. Clinical variables assessed include mechanism of injury, neurological status, CTA findings, subsequent imaging results, patient management, and clinical outcomes. RESULTS: Among 1290 patients who underwent CTA, 200 (15.5%) were positive for TCVI, higher in blunt than penetrating trauma patients. In a generalized linear model, factors that increased likelihood of positive CTA included multiple cervical fractures, fractures with foraminal involvement, gunshot injury, Glasgow Coma Scale ≤ 13, and focal neurological deficit. Excluding cases with these factors lowered the positive rate to 4.3%. Of the 200 CTA-positives, 99 were treated for TCVI and 9 (4.5%) developed a subsequent stroke as compared to 5 (0.5%) in CTA-negative patients (odds ratio 10.2, Fisher exact test, p < 0.001). Risk of death or nursing facility discharge location was also higher in CTA-positive patients, correcting for age and presenting GCS (p < 0.01). CONCLUSION: CTA had a modest yield in identifying TCVI in this cohort. When positive, CTA influenced management and predicted an increased risk of subsequent stroke and poor outcome.