Detection of diminished response to cold pressor test in smokers: assessment using phase-contrast cine magnetic resonance imaging of the coronary sinus.
OBJECTIVE
The purposes of this study were to evaluate the reproducibility for measuring the cold pressor test (CPT)-induced myocardial blood flow (MBF) alteration using phase-contrast (PC) cine MRI, and to determine if this approach could detect altered MBF response to CPT in smokers.


METHODS
After obtaining informed consent, ten healthy male non-smokers (mean age: 28±5 years) and ten age-matched male smokers (smoking duration ≥5 years, mean age: 28±3 years) were examined in this institutional review board approved study. Breath-hold PC cine MR images of the coronary sinus were obtained with a 3T MR imager with 32 channel coils at rest and during a CPT performed after immersing one foot in ice water. MBF was calculated as coronary sinus flow divided by the left ventricular (LV) mass which was given as a total LV myocardial volume measured on cine MRI multiplied by the specific gravity (1.05 g/mL).


RESULTS
In non-smokers, MBF was 0.86±0.25 mL/min/g at rest, with a significant increase to 1.20±0.36 mL/min/g seen during CPT (percentage change of MBF (∆MBF (%)); 39.2%±14.4%, p<0.001). Inter-study reproducibility for ∆MBF (%) measurements by different MR technologist was good, as indicated by the intraclass correlation coefficient of 0.93 and reproducibility coefficient of 10.5%. There was no significant difference between smokers and non-smokers for resting MBF (0.85±0.32 mL/min/g, p=0.91). However, ∆MBF (%) in smokers was significantly reduced (-4.0±32.2% vs. 39.2±14.4%, p=0.011).


CONCLUSIONS
PC cine MRI can be used to reproducibly quantify MBF response to CPT and to detect impaired flow response in smokers. This MR approach may be useful for monitoring the sequential change of coronary blood flow in various potentially pathologic conditions and for investigating its relationship with cardiovascular risk.
Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Shingo
S
Kato
Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan. Electronic address: kakuya@clin.medic.mie-u.ac.jp.
Kakuya
K
Kitagawa
Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Yeonyee E
YE
Yoon
Department of Cardiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Hiroshi
H
Nakajima
Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Motonori
M
Nagata
Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Shinichi
S
Takase
Department of Cardiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Shiro
S
Nakamori
Department of Cardiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Masaaki
M
Ito
Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
Hajime
H
Sakuma
D000328:Adult; D000465:Algorithms; D003080:Cold Temperature; D003324:Coronary Artery Disease / Q000473:pathology / Q000503:physiopathology*; D003326:Coronary Circulation; D054326:Coronary Sinus / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012907:Smoking / Q000473:pathology / Q000503:physiopathology*
3T MR imager; Cold Pressor Test; Coronary endothelial function; Nitric oxide; Phase-Contrast Cine Magnetic Resonance Imaging; Smoker