The Optimization of Scan Timing for Contrast-Enhanced Magnetic Resonance Angiography.
- Author:
Jongmin J LEE
1
;
Phillip J TIRMAN
;
Yong Min CHANG
;
Hun Kyu RYEOM
;
Sang Kwon LEE
;
Yong Sun KIM
;
Duk Sik KANG
Author Information
- Publication Type:Original Article
- Keywords: Magnetic resonance (MR), angiog-raphy; Magnetic resonance (MR), con-trast,enhancement; Aorta, MR
- MeSH: *Contrast Media; Female; Gadolinium DTPA/*diagnostic use; Human; Image Processing, Computer-Assisted; Injections, Intravenous; Magnetic Resonance Angiography/*methods; Male; Middle Age; Time Factors
- From:Korean Journal of Radiology 2000;1(3):142-151
- CountryRepublic of Korea
- Language:English
- Abstract: OBJECTIVE: To determine the optimal scan timing for contrast-enhanced magnetic resonance angiography and to evaluate a new timing method based on the arteriovenous circulation time. MATERIALS AND METHODS: Eighty-nine contrast-enhanced magnetic resonance angiographic examinations were performed mainly in the extremities. A 1.5T scanner with a 3-D turbo-FLASH sequence was used, and during each study, two consecutive arterial phases and one venous phase were acquired. Scan delay time was calculated from the time-intensity curve by the traditional (n = 48) and/or the new (n = 41) method. This latter was based on arteriovenous circulation time rather than peak arterial enhancement time, as used in the traditional method. The numbers of first-phase images showing a properly enhanced arterial phase were compared between the two methods. RESULTS: Mean scan delay time was 5.4 sec longer with the new method than with the traditional. Properly enhanced first-phase images were found in 65% of cases (31/48) using the traditional timing method, and 95% (39/41) using the new method. When cases in which there was mismatch between the target vessel and the time-intensity curve acquisition site are excluded, erroneous acquisition occurred in seven cases with the traditional method, but in none with the new method. CONCLUSION: The calculation of scan delay time on the basis of arteriovenous circulation time provides better timing for arterial phase acquisition than the traditional method.
