Publications by authors named "Alexander Mamourian"

Background And Purpose: Imaging and autopsy studies show intracranial gadolinium deposition in patients who have undergone serial contrast-enhanced MRIs. This observation has raised concerns when using contrast administration in patients who receive frequent MRIs. To address this, we implemented a contrast-conditional protocol wherein gadolinium is administered only for multiple sclerosis (MS) patients with imaging evidence of new disease activity on precontrast imaging.

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Objectives: While hemorrhage arising from ruptured arteriovenous malformations (AVMs) is usually evident on multidetector non-contrast computed tomography (NCCT), unruptured AVMs can be below the limits of detection. We performed a retrospective review of NCCT of patients with a proven diagnosis of unruptured AVM to determine if advances in CT technology have made them more apparent and what features predict their detection.

Material And Methods: Twenty-five NCCTs met inclusion criteria of having angiography or MR proven AVM without hemorrhage, prior surgery, or other CNS disease.

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Objective: In adult patients undergoing multidetector computed tomography (CT) of the brain, we observed linear calcification along the deep venous system on thin (<3 mm) sagittal reconstructions. We found no reports of this finding in the velum interpositum (VI) in the imaging literature. We performed a focused examination of the VI on 2 autopsy cases and retrospectively reviewed sagittal, thin-section reconstructions of CT scans of 273 consecutive adult patients.

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The purpose of this study was to show, by use of a phantom, that magnetic eyelashes worn in the MRI environment can cause substantial artifact and that detachment of the eyelashes from the phantom can occur. A new cosmetic product, magnetic eyelashes, should be of interest and concern to radiologists and technologists working in the MRI environment. We strongly recommend inserting a line about magnetic eyelashes on the MRI safety questionnaire and adding stops in the screening system to prevent the entry of anyone with these lashes, including staff, into the MRI scanner room.

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Objective: Patients with multiple sclerosis (MS) routinely undergo serial contrast-enhanced MRIs. Given concerns regarding tissue deposition of gadolinium-based contrast agents (GBCAs) and evidence that enhancement of lesions is only seen in patients with new disease activity on noncontrast imaging, we set out to implement a prospective quality improvement project whereby intravenous contrast would be reserved only for patients with evidence of new disease activity on noncontrast images.

Methods: To prospectively implement such a protocol, we leveraged our in-house computer-assisted detection (CAD) software and 3-D laboratory radiology technologists to perform real-time preliminary assessments of the CAD-processed T2 fluid attenuated inversion recovery (FLAIR) noncontrast images as a basis for deciding whether to inject contrast.

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Background And Purpose: Hyperintensity on T1-weighted imaging in perilesional vasogenic edema has been reported as a useful sign for differentiating cavernous malformation from other hemorrhagic intra-axial masses. In this study, we investigated the frequency of perilesional hyperintensity on T1-weighted imaging in patients with intra-axial hemorrhagic and nonhemorrhagic brain masses.

Methods: The study was performed with the approval of the institutional review board.

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Developmental venous anomalies (DVAs) are the most common cerebral vascular malformations and are usually found incidentally on neuroimaging studies. Despite the benign nature of DVAs, occasionally, they can be symptomatic. The objective of this article is to review the spectrum of imaging findings of DVAs on conventional and advanced imaging studies.

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Objective: While haemangiomas are common benign vascular lesions involving the spine, some behave in an aggressive fashion. We investigated the utility of fat-suppressed sequences to differentiate between benign and aggressive vertebral haemangiomas.

Methods: Patients with the diagnosis of aggressive vertebral haemangioma and available short tau inversion-recovery or T2 fat saturation sequence were included in the study.

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Acute myeloid leukemia (AML) is a hematologic malignancy that can present with central nervous system (CNS) symptoms. Neurological symptoms may result from the local accumulation of malignant cells in or near the brain (chloroma), infection, hemorrhage, or infarcts from leukostasis. Leukostasisis a syndrome that can include brain infarction due hyperviscosity of blood with vascular occlusion but CNS involvement is rarely encountered in adults.

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Spinal dural arteriovenous fistula (DAVF) is an uncommon condition that can be difficult to diagnose. This often results in misdiagnosis and treatment delay. Although conventional MRI plays an important role in the initial screening for the disease, the typical MRI findings may be absent.

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Rationale And Objectives: The purpose of this study was to present a new methodology to compare accuracies of two imaging fluid attenuated inversion recovery (FLAIR) magnetic resonance sequences in detection of multiple sclerosis (MS) lesions in the brain in the absence of ground truth, and to determine whether the two sequences, which differed only in echo time (TE), have the same accuracy.

Materials And Methods: We acquired FLAIR images at TE(1) = 90 ms and TE(2) = 155 ms from 46 patients with MS (24-69 years old, mean 45.8, 15 males) and 11 healthy volunteers (23-54 years old, mean 37.

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The authors report the case of a large cranial cavernous hemangioma that was treated using embolization and craniotomy with preservation of the outer cranial table. A 3-year follow-up demonstrated no recurrence. Results in this case suggest that cavernous hemangiomas of the cranium may be safely and effectively treated without craniectomy in some cases.

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Object: In this paper, the authors' goal was to determine whether benign pineal cysts have smooth walls or internal structure on high-resolution MR imaging and to evaluate their imaging characteristics on FLAIR images.

Methods: The authors retrospectively reviewed the MR imaging findings in 60 consecutive patients who were reported to have pineal cysts over a 19-month period. Patients were identified retrospectively using a word search of radiology reports.

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Objectives: Computerized tomographic angiography (CTA) has emerged as a valuable diagnostic tool for the management of patients with cerebrovascular disease. The use of CTA in lieu of, or as an adjunct to, conventional cerebral angiography in the management of cerebral aneurysms awaits further experience. In this study, we evaluated the role of CTA specifically for the pre-operative assessment and planning of cerebral aneurysm surgery.

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Developmental venous anomalies (DVAs) are generally considered a benign and asymptomatic finding on CT and MR imaging. The authors report 2 cases of spontaneous thrombosis of the draining vein of a DVA depicted on CT and MR imaging. One patient presented with a nonhemorrhagic transient ischemia, which was successfully treated with anticoagulant therapy.

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