Brain magnetic resonance imaging at 3 Tesla using BLADE compared with standard rectilinear data sampling.

OBJECTIVES: We sought to evaluate Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER; BLADE) data acquisition in comparison with standard k-space sampling techniques for axial and sagittal brain imaging at 3 T regarding imaging artifacts. MATERIAL AND METHODS: Forty patients who gave consent were included in a prospective comparison of standard and PROPELLER (BLADE) k-space sampling techniques. All examinations were performed at 3 T with comparison of standard T2-weighted fluid-attenuated inversion recovery (FLAIR) to PROPELLER T2-weighted FLAIR in the axial image orientation and standard T1-weighted gradient echo to PROPELLER T1-weighted FLAIR in the sagittal image orientation. Imaging protocols were matched for spatial resolution, with data evaluation performed by 2 experienced neuroradiologists. Image data were compared regarding various image artifacts and overall image quality. Reader agreement was assessed by Cohen's kappa statistics. RESULTS: PROPELLER T2-weighted axial data acquisition showed significantly less pulsation and Gibb's artifacts than the standard T2-weighted scan. Even without motion correction, the frequency of ghosting (motion) artifacts was substantially lower in the PROPELLER T2-weighted data and readers concordantly (kappa = 1) rated PROPELLER as better than or equal to the standard T2-weighted scan in the majority of cases (95%; P < 0.0001). In the comparison of sagittal T1-weighted data sets, readers showed only fair agreement (kappa = 0.24) and noted consistent wrap artifacts in PROPELLER T1-weighted FLAIR. CONCLUSION: PROPELLER (BLADE) brain magnetic resonance imaging is also applicable at 3 T. In addition to minimizing motion artifacts, the PROPELLER acquisition scheme reduces other magnetic resonance artifacts that would otherwise degrade scan quality.

T1-weighted imaging of the brain at 3 tesla using a 2-dimensional spoiled gradient echo technique.

RATIONALE AND OBJECTIVES: The objective of this study was to evaluate a 2-dimensional spoiled gradient echo (GRE) imaging approach using a very short in-phase TE for routine T1-weighted imaging of the brain at 3 T. MATERIALS AND METHODS: Patient examinations were compared from a 3 T magnetic resonance (MR) unit located immediately adjacent to a similarly equipped 1.5 T unit. Pre- and postcontrast T1-weighted images were evaluated and compared at 1.5 versus 3 T with a 2-dimensional (2-D) spin echo sequence used at 1.5 T and a 2-D GRE sequence at 3 T. The 2 MR systems used are from the same vendor, use similar 8-channel coils, and use identical gradients. The T1-weighted GRE sequence, used at 3 T, relies on a short TE (2.4 ms) to limit flow-related and susceptibility artifacts. Region-of-interest analysis was performed on 16 different sagittal patient examinations at both field strengths (32 total) and similarly on 10 different pre- and postcontrast axial examinations (40 total). Four blinded neuroradiologists also evaluated these studies. RESULTS: Using an off-midline sagittal slice depicting the caudate nucleus (signal-to-noise ratio [SNR] 163 +/- 28 vs. 70 +/- 7, 3 T vs. 1.5 T) and corona radiata (SNR 214 +/- 35 vs. 82 +/- 10), 3 T markedly outperformed 1.5 T in both SNR and contrast-to-noise ratio (CNR) (51 +/- 14 vs. 12 +/- 5). On axial imaging, despite a reduction in slice thickness (5 to 3 mm) and scan time (5 to 1 minute), there was no significant difference pre- or postcontrast in SNR and CNR comparing 3 and 1.5 T. On blinded film review, 3 T performed slightly better on sagittal scans than 1.5 T in regard to motion artifacts (reduced), gray-white matter differentiation, and overall image quality. On axial scans, 3 T performed markedly better in all 3 categories both pre- and postcontrast. In regard to overall image quality, 3 T was preferred 9:2 precontrast and 4:1 postcontrast. CONCLUSIONS: High-quality, thin-section (3-mm) T1-weighted imaging can be readily performed at 3 T using a short TE 2-D GRE technique. This approach offers superior SNR and CNR with reduced motion artifacts and scan time as compared with imaging at 1.5 T and is advocated for routine brain imaging at 3 T. It is robust (used in over 1500 patients to date) and does not experience significant specific absorption ratio limitations, poor tissue contrast, or accentuated motion artifacts like encountered with spin echo T1-weighted imaging at 3 T.

Optimizing the latest neuroradiology tools. New techniques are particularly useful in stroke management.

In the past several years, advances in central nervous system imaging and interventional techniques have directly and dramatically improved healthcare. In this article, Drs Naul and Santiago discuss developments in magnetic resonance imaging (MRI) and interventional neuroradiology. In addition, the role of these techniques in the management of strokes is highlighted.

Radiology goes filmless. What does this mean for primary care physicians?

Technical advances over the past few years have rapidly increased the possibilities for filmless radiology services provided by PACS. Such systems are also financially feasible for many healthcare practices, primarily because of the goals achieved through increased efficiency and improved patient care. In coming years, most medical facilities are likely to either convert or begin to convert to PACS as conventional film-based systems fade into the annals of medical history.

Intracranial infantile hemangiopericytoma.

Hemangiopericytoma (HP) is a rare vascular tumor that usually occurs in adults, but 10% occur in children. Tumors occurring in the first year of life are even more rare and are referred to as infantile hemangiopericytoma. In this article, we report the imaging, operative, and pathological findings in a patient with an infantile HP.

Extensive cerebrospinal fluid enhancement with gadopentetate dimeglumine in a primitive neuroectodermal tumor.

We report a case of diffuse enhancement of the cerebrospinal fluid (CSF) after intravenous administration of gadopentetate dimeglumine in an 8-year-old girl with a primitive neuroectodermal tumor. The enhancement of the CSF was caused by leakage of gadolinium chelate complexes into the CSF, which was proved by CSF analysis.

Gliosarcoma: MR features.

PURPOSE: Our goal was to characterize the MR features of pathologically documented gliosarcoma and to determine if these features help differentiate gliosarcoma from other intracranial neoplasms. METHOD: MR studies of six patients with pathologically documented gliosarcoma were retrospectively analyzed. RESULTS: The tumors tended to be well defined lesions demonstrating either an inhomogeneous or cystic appearance with surrounding vasogenic edema. All tumors were characterized as primarily intraaxial but abutting a dural surface. On T2-weighted images, all tumors were of intermediate signal intensity with surrounding edema. The signal intensity of the tumor was similar to gray matter but was hypointense relative to other glial neoplasms. Postcontrast T1-weighted images showed intense tumor enhancement, often with a ring-like appearance. The isointense component on the T2-weighted images corresponded to this area of intense enhancement. CONCLUSION: Gliosarcoma exhibits some characteristic MR features. It should be included in the differential diagnosis of any tumor that appears to be intraaxial but abuts a dural surface and is much less hypointense on T2-weighted images than other glial neoplasms.

Intramedullary gliofibroma: MR, ultrasound, and pathologic correlation.

We describe the clinical, MR, ultrasound, and pathologic findings of an intramedullary gliofibroma. This uncommon primitive tumor is thought to be of mixed glial and mesenchymal origin. Although the majority of tumors described to date have been histologically benign, clinical course has been quite variable. On MRI, the tumor we report was isointense to adjacent spinal cord on T1-weighted imaging and became hyperintense on proton and T2-weighted imaging. Enhancement with gadolinium diethylenetriamine pentaacetic acid was mild and slightly heterogeneous. Intraoperative ultrasound demonstrated widening of the lower thoracic cord. Echo pattern was generally similar to that of adjacent cord. The major differential diagnostic considerations include astrocytoma and ependymoma.

Intraventricular fibroma: MR and pathologic comparison.

This case report describes clinical, surgical, MR, and pathologic findings of an intraventricular fibroma, a rare, benign mesenchymal neoplasm. Relatively isointense with normal brain parenchyma on T1-weighted images, the tumor exhibited hyperintense signal on T2-weighted pulse sequences and enhanced intensely and homogeneously after intravenous administration of gadopentetate dimeglumine. Choroid plexus papilloma/carcinoma, meningioma, ependymoma, and subependymal giant cell astrocytoma should be included in the differential diagnosis.

Intracranial granulocytic sarcoma: CT, MR, and angiography.

Granulocytic sarcoma is a rare, solid tumor composed of immature granulocytes usually found in association with systemic leukemia in younger patients. We present a case of granulocytic sarcoma occurring in an elderly female with no evidence of systemic leukemia. Computed tomography, MR (with and without Gd-DTPA), and angiography showed features commonly found in meningiomas.

Paraplegia after a routine lumbar laminectomy: report of a rare complication and successful management.

Arachnoid cysts of the spinal canal are relatively common lesions that may be either intra- or extradural. These cysts are usually asymptomatic but may produce symptoms by compressing the spinal cord or nerve roots. We report a case in which an intradural thoracic arachnoid cyst became symptomatic after a routine decompressive lumbar laminectomy for spinal stenosis. Myelography revealed no abnormality, although magnetic resonance imaging and computed tomography after myelography demonstrated a mass within the posterior aspect of the thoracic spinal canal associated with anterior displacement and compression of the spinal cord. A change in the flow dynamics of the cerebrospinal fluid probably allowed the development of spinal cord compression due to one of the following: expansion of the cyst, decreased cerebrospinal fluid buffer between the cord and the cyst, or epidural venous engorgement. A concomitant and more cephalad lesion such as an arachnoid cyst should be considered when myelopathic complications arise after lumbar surgery. Magnetic resonance imaging and computed tomography after myelography are useful to demonstrate the additional pathological processes.

Avascular necrosis of the vertebral body: MR imaging.

Five patients with plain radiographic evidence of a compressed vertebra containing an intravertebral vacuum cleft indicative of avascular necrosis underwent magnetic resonance (MR) imaging. In these patients, the T2-weighted images revealed a distinct appearance consisting of marked and discrete hyperintensity at the location of the intravertebral cleft. T1-weighted images were hypointense in this region. Recognition of this pattern is important in the MR imaging evaluation of compression fractures of the vertebral body so that confusion with malignancy or infection may be avoided, thereby obviating additional diagnostic studies.

Gallium-67 uptake by a benign adrenocortical adenoma.

A 55-yr-old man presented with an atypical relapsing meningitis and was found to have intense unilateral adrenal uptake by 67Ga imaging. Computed tomography showed a 4-cm right adrenal mass which was hypointense on the T1-weighted images and mildly hyperintense on the T2-weighted images of a magnetic resonance (MR) scan. At surgery, a coincidental benign adrenocortical adenoma was found. Because 67Ga uptake is usually associated with inflammatory or malignant lesions and malignant adrenal lesions are hyperintense on T2-weighted MR images, these findings contributed to diagnostic uncertainty in this patient. Thus, a nonhyperfunctional adrenocortical adenoma may be associated with abnormal 67Ga uptake and atypical MR findings.