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Biomedical subjects

G Krinsky

Publications and source records attributed to G Krinsky.

At least 19 recordsLinked to original sources
PubMed1998

MR angiography of the aortic arch vessels and upper extremities.

MR angiography of the aortic arch vessels and upper extremities is a noninvasive alternative to conventional catheter angiography without the risks of stroke or the potential toxicity of iodinated contrast. The use of optimized, breath hold gadolinium-enhanced three-dimensional MR angiography provides excellent image quality with the capability of display options not available with conventional angiography. This article demonstrates the utility of this new technique in the diagnosis of congenital and acquired conditions of the supraaortic vascular system.

Aneurysm↗
PubMed1998

MR angiography of the thoracic aorta.

MR angiography is a powerful tool in evaluating the complete spectrum of congenital and acquired diseases of the thoracic aorta. The use of gadolinium-chelates in conjunction with rapid three-dimensional sequences performed with breath holding provides robust image quality with multiple display options. As a result of technological advances in hardware, software, and pulse sequence implementation combined with innovative use of contrast agents, MR angiography is poised to replace conventional catheter angiography of the thoracic aorta for many indications.

Aorta, Thoracic↗
PubMed1997

Suppression of venous signal in time-of-flight MR angiography of the lower extremities after administration of gadopentetate dimeglumine.

PURPOSE: To evaluate a magnetic resonance (MR) angiography time-of-flight technique that can effectively suppress venous signal after gadopentetate dimeglumine administration. MATERIALS AND METHODS: Twelve adult patients underwent MR angiography for the evaluation of peripheral vascular disease. Gradient-echo sequences were performed after the administration of 0.2 mmol/kg gadopentetate dimeglumine. Three sequences were compared: a nontriggered sequence; a gap sequence, an electrocardiographically triggered, segmented sequence with a 7-mm gap between saturation and imaging sections; and a no-gap sequence, a similar sequence as gap but with partially overlapping imaging and saturation sections. For each sequence, identical regions of interest were generated for arterial, venous, and background muscle tissue and noise. A paired Student t test was used to compare the signal-to-noise and contrast-to-noise ratios (C/Ns) among the sequences. In seven patients, the no-gap sequence was used to acquire MR angiograms of the distal lower extremities. RESULTS: The mean artery-muscle C/N was similar for the triggered sequences; both were statistically significantly greater than the ratios for the nontriggered sequence. Venous suppression was much better with the no-gap sequence. Overall, the best artery-vein C/N was also obtained with the no-gap sequence. MR angiograms with effective venous suppression could be obtained only with the no-gap sequence. CONCLUSION: Time-of-flight MR angiograms can be obtained with effective venous suppression after the administration of 0.2 mmol/kg gadopentetate dimeglumine.

Aged↗
PubMed1996

Gadolinium-enhanced three-dimensional MR angiography of the thoracoabdominal aorta.

MR angiography (MRA) of the thoracoabdominal aorta is a noninvasive technique that can rapidly acquire a volume of data with the capability of multiplaner reformations (MPR) and "bright blood" maximum intensity projection (MIP) angiographic images. These MIP images can display long tortuous vessels in a single three-dimensional (3D) volume, with excellent delineation of branch vessel diseases and without the flow artifacts or long examination times of conventional spin-echo (SE) imaging. Two-dimensional (2D) time-of-flight (TOF) imaging is used most widely because of familiarity and ease of implementation, but this method has limitations in evaluating thoracoabdominal aortic disease. Sequential 2D axial imaging (which maximizes flow-related enhancement) is time consuming, subject to slice-to-slice misregistration, and can be degraded by pulsatile and turbulent flow. Coronal or parasagittal imaging is more time efficient, but image degradation secondary to in plane saturation and stagnant or turbulent flow from aneurysmal disease may lead to nondiagnostic studies. Three-dimensional TOF techniques offer the advantages of higher signal-to-noise ratio, better spatial resolution with near isotropic voxels, and shorter echo times (TEs), which lessen signal loss because of intravoxel phase dispersion. Although these techniques provide excellent image quality in the carotid arteries, they are of limited use in the aorta because of saturation effects. However, the addition of gadolinium chelates shortens the T1 relaxation rate of blood, which obviates the need for flow-related enhancement, allowing for inplane imaging without saturation effects, even in regions of virtually stagnant flow. The enormous signal enhancement of gadolinium chelates enables imaging with high-resolution matrices, providing diagnostic angiograms in as little as 2 minutes. With improved hardware, faster and stronger gradients, and phased-array coils that increase the signal-to-noise ratio, breath-hold gadolinium-enhanced 3D schemes with ultrashort TEs will become the optimal method for imaging the aorta and its branch vessels. Using this technique, the aorta can be imaged in less than 1 minute.

Aorta, Abdominal↗
PubMed1996

Nonspecificity of short inversion time inversion recovery (STIR) as a technique of fat suppression: pitfalls in image interpretation.

Short inversion time inversion recovery (STIR) and the rapid acquisition with relaxation enhancement (RARE) version of STIR are commonly used pulse sequences that are sensitive enough to detect a broad range of pathologic conditions. In addition to suppressing the signal from fat, the STIR sequence achieves additive T1-weighted, T2-weighted, and proton density-weighted contrast to facilitate lesion conspicuity [1, 2]. Fat suppression with STIR sequences is based on short T1 relaxation rates and therefore is not tissue specific. The signal from any tissue with a short T1, similar to that of fat, may be nulled as well. The signal from tissues that accumulate paramagnetic contrast agents also may be suppressed with STIR sequences when an appropriate degree of T1 shortening results.

Adipose Tissue↗
PubMedDate not supplied

Rapid T2-weighted MR imaging of uterine leiomyoma and adenomyosis.

BACKGROUND: To compare three rapid T2-weighted pulse sequences with high-resolution turbo spin-echo (SE) magnetic resonance (MR) imaging for the diagnosis of leiomyoma and adenomyosis. METHODS: Eighteen patients referred for evaluation of suspected leiomyoma or adenomyosis underwent imaging at 1.5 T with a phased-array multicoil. Non-breath-hold, fat-saturated sagittal images of 4-7 mm, with equivalent voxel size, were obtained through the pelvis with the following three rapid pulse sequences: segmented, half-Fourier single shot turbo SE (HASTE), turboGRASE (TGSE) and turbo SE MR images. Mean acquisition times were 17 s (HASTE), 37 s (TGSE), and 42 s (turbo SE). These images were compared, in a blinded fashion, to high resolution turbo SE MR images, which are considered the "standard" for pelvic MRI. RESULTS: The three rapid pulse sequences, HASTE, TGSE and turbo SE, provided equivalent diagnostic information when compared with high-resolution turbo SE MR images. There was no significant difference in image quality, detection and localization of leiomyoma or in diagnosis of adenomyosis among the three rapid sequences. HASTE imaging demonstrated the least ghosting. CONCLUSION: Diagnostic T2-weighted images of benign uterine pathology may be obtained in as little as 17 s.

Adult↗