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Time-resolved MR angiography of the legs at 3 T using a low dose of gadolinium: initial experience and contrast dynamics.

ABSTRACT: This article describes our initial clinical experience with time-resolved MR angiography (MRA) of the legs using the time-resolved imaging with stochastic trajectories (TWIST) technique with a half dose of gadolinium.Thirty-four patients underwent a TWIST examination of the legs at 3 T. Thirty-three patients also underwent a bolus-chase MRA examination in the same setting. Times elapsed between the start of contrast injection and the appearance of contrast material (t(A)) and peak enhancement of the arteries in the legs (t(B)) were analyzed. The number of patients with examinations affected by venous contamination was determined. The differences in t(A) and t(B) between cases in which venous contamination was present or absent were evaluated using a two-tailed Student t test.The TWIST technique using a half dose of gadolinium provided diagnostic-quality images of all patients. The mean t(A) was 35.5 ± 8.8 (SD) seconds (range, 17.8-60.4 seconds), and the mean t(B) was 59.1 ± 15.1 seconds (range, 31-98.8 seconds). Venous contamination was observed in bolus-chase MRA images of 52.9% of patients. The relationship between venous contamination and t(A) was not statistically significant (p = 0.13). The incidence of venous contamination was higher in patients with lower values of t(B) (p = 0.01).The described low-dose clinical experience with TWIST and the contrast dynamics information gained from this study could aid radiologists in planning protocols for leg MRA examinations.

SUBMITTER: Sandhu GS

PROVIDER: S-EPMC3963831 | biostudies-literature | 2012 Mar

REPOSITORIES: biostudies-literature

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Time-resolved MR angiography of the legs at 3 T using a low dose of gadolinium: initial experience and contrast dynamics.

Sandhu Gurpreet Singh GS Rezaee Rod P RP Jesberger John J Wright Katherine K Griswold Mark A MA Gulani Vikas V

AJR. American journal of roentgenology 20120301 3

<h4>Objective</h4>This article describes our initial clinical experience with time-resolved MR angiography (MRA) of the legs using the time-resolved imaging with stochastic trajectories (TWIST) technique with a half dose of gadolinium.<h4>Materials and methods</h4>Thirty-four patients underwent a TWIST examination of the legs at 3 T. Thirty-three patients also underwent a bolus-chase MRA examination in the same setting. Times elapsed between the start of contrast injection and the appearance of ...[more]

PMID: 22358010

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Project description:PurposeTo evaluate the use of low-dimensional-structure self-learning and thresholding (LOST) compressed sensing acquisition and reconstruction in the assessment of left atrial (LA) and left ventricular (LV) scar by using late gadolinium enhancement (LGE) magnetic resonance (MR) imaging with isotropic spatial resolution.Materials and methodsThe study was approved by the local institutional review board and was compliant with HIPAA. All subjects provided written informed consent. Twenty-eight patients (eight women; mean age, 58.0 years ± 10.1) with a history of atrial fibrillation were recruited for the LA LGE study, and 14 patients (five women; mean age, 54.2 years ± 18.6) were recruited for assessment of LV myocardial infarction. With use of a pseudorandom k-space undersampling pattern, threefold accelerated three-dimensional (3D) LGE data were acquired with isotropic spatial resolution and reconstructed off-line by using LOST. For comparison, subjects were also imaged by using standard 3D LGE protocols with nonisotropic spatial resolution. Images were compared qualitatively by three cardiologists with regard to diagnostic value, presence of enhancement, and image quality. The signed rank test and Wilcoxon unpaired two-sample test were used to test the hypothesis that there would be no significant difference in image quality ratings with different resolutions.ResultsInterpretable images were obtained in 26 of the 28 patients (93%) in the LA LGE study. LGE was seen in 17 of 30 cases (57%) with nonisotropic resolution and in 18 cases (60%) with isotropic resolution. Diagnostic quality scores of isotropic images were significantly higher than those of nonisotropic images with coronal views (median, 3 vs 2, respectively [25th and 75th percentiles: 3, 3 vs 2, 3]; P < .001) and sagittal views (median, 3 vs 2 [25th and 75th percentiles: 3, 4 vs 2, 3]; P < .001) but lower with axial views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 3, 3]; P < .001). For the LV LGE study, all patients had interpretable images. LGE was seen in six of 14 patients (43%), with 100% agreement between both data sets. Diagnostic quality scores of high-isotropic-resolution LV images were higher than those of nonisotropic images with short-axis views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 2, 3]; P = .014) and two-chamber views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 2, 3]; P = .001).ConclusionAn accelerated LGE acquisition with LOST enables imaging with high isotropic spatial resolution for improved assessment of LV, LA, and pulmonary vein scar.

Dataset Information

Time-resolved MR angiography of the legs at 3 T using a low dose of gadolinium: initial experience and contrast dynamics.

Publications

Time-resolved MR angiography of the legs at 3 T using a low dose of gadolinium: initial experience and contrast dynamics.

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