Shingo Kato MD, Presenter: Nothing to Disclose

Kakuya Kitagawa MD, Abstract Co-Author: Nothing to Disclose

Yeonyee Elizabeth Yoon, Abstract Co-Author: Nothing to Disclose

Motonori Nagata MD, PhD, Abstract Co-Author: Nothing to Disclose

Shinichi Takase, Abstract Co-Author: Nothing to Disclose

Hajime Sakuma MD, Abstract Co-Author: Nothing to Disclose

Coronary endothelial dysfunction can provide detection of early state of atherosclerosis and has been assessed with acetylcholine test during coronary angiography or PET measurements of myocardial blood flow (MBF) at rest and during cold pressor test (CPT). The purposes of this study were to evaluate the feasibility and reproducibility of noninvasive MR measurement of endothelium-dependent blood flow increase during CPT in the coronary sinus by using 3T MR imager, and to determine if MR CPT test can detect altered coronary endothelial function in young smokers.

Ten control subjects (age: 28±5years) and age-matched 10 smokers (smoking duration ≥5 years, age: 29±4 years) without cardiovascular risk factors were studied with a 3T MR imager and 32 channel coils. Breath hold phase contrast cine MR images of coronary sinus were obtained at rest and during CPT by immersing the foot in ice water (TR/TE = 7.3/4.4 msec, Venc = ±50 cm/sec). LV mass was determined on short axis cine MRI. MBF was calculated as coronary sinus blood flow divided by LV myocardial mass.  To evaluate inter-study, intra- and inter-observer reproducibilities, rest and CPT studies were repeated by two independent operators and were analyzed by two independent observers.

In control subjects, MBF was 0.96±0.28 ml/min/g in the resting state and increased to 1.28±0.35 ml/min/g during CPT (p=0.038), with an averaged increase of 34±11%. Inter-operator, intra- and inter-observer variability for measuring the increase in MBF was low, with a mean difference of -3.0% (95% limit of agreement; -16.1 to 10.1%), -0.3% (-9.7 to 9.1%), and -2.8% (-12.1 to 6.6%), respectively. In smokers, rest MBF (0.85±0.28 ml/min/g) was not significantly different from that in control subjects. However, the average increase in MBF was significantly reduced in smokers in compared with control subjects (0±27% vs 34±11%, p=0.003).

MBF response to CPT can be quantified by using 3T phase contrast cine MRI with higher reproducibilities in comparison to those reported in previous studies using PET. Impaired coronary endothelial function in young smokers was clearly demonstrated with a MR CPT method.

CPT test using 3T MRI is a feasible and reproducible method for the non-invasive assessment of coronary endothelial function, and may provide an early detection of diffuse coronary atherosclerosis.

Kato, S, Kitagawa, K, Yoon, Y, Nagata, M, Takase, S, Sakuma, H, Noninvasive Assessment of Coronary Endothelial Function with Cold Pressor Test by Using 3 T Phase Contrast Cine MRI.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008075.html