We used single-photon emission computed tomography to measure cerebral blood flow, cerebral blood volume, and cerebral perfusion reserve and transcranial Doppler sonography with CO, stimulation to assess hemispheric vasomotor reactivity in 37 patients and in normal controls. Computed tomography and magnetic resonance imaging were performed to differentiate morphologically low-flow infarcts (n=1...

BACKGROUND The assessment of functional coronary lesion severity using intracoronary physiological parameters such as coronary flow velocity reserve and the more widely used fractional flow reserve relies critically on the establishment of maximal hyperemia. We evaluated the diagnostic accuracy of the stenosis resistance index during nonhyperemic conditions, baseline stenosis resistance index, ...

We simultaneously assessed the blood flow index (BFI) in three respiratory muscles during hyperpnea and high-intensity constant-load cycling sustained at comparable levels of work breathing neural drive patients with COPD. demonstrated that exercise impairs muscle perfusion, as intercostal, scalene, abdominal BFI increased but not cycling. Insufficient adjustment perfusion was associated greate...

Loss of cerebrovascular reserve with the resultant increase of cerebral perfusion, and disruption of capillary fluid balance generally leads to the development of cerebral edema, a serious secondary complication of traumatic brain injury. Two indices of cerebrovascular reserve derived from recordings of intracranial pressure (ICP) and arterial blood pressure (ABP) have been proposed [1-3]. The ...

BACKGROUND AND PURPOSE Perfusion MR imaging and single-photon emission CT (SPECT) are commonly used to evaluate hemodynamic status in patients with symptomatic occlusive cerebrovascular disease. These techniques rely on different underlying physiological mechanisms, and the data may not correspond. We studied the relationship between hemodynamic parameters obtained with these two methods. MET...

Retinal arteriolar narrowing is a marker of chronic hypertension. Myocardial perfusion reflects microvascular processes in the heart. The relationship between these 2 measures has not been studied previously and is examined in 212 men and women aged 45 to 84 years and free of cardiovascular disease diagnoses. Retinal caliber was measured through fundus photography and presented as central retin...

OBJECTIVES Previous studies have demonstrated a decreased flow reserve in the surviving hypertrophied left ventricle (LV) early after myocardial infarction. We hypothesized that exacerbation of hemodynamic abnormalities and neurohumoral activation during exercise could exhaust coronary flow reserve and thereby impair myocardial O(2) supply. Consequently, we studied hemodynamic, neurohumoral and...

BACKGROUND AND PURPOSE We evaluated whether basal/acetazolamide stress brain perfusion SPECT performed after revascularization surgery can predict the further clinical outcome of patients with pediatric moyamoya disease. METHODS A total of 77 (31 males, 46 females, age 6.6+/-3.2 years) patients with postoperative pediatric moyamoya disease who underwent basal/acetazolamide stress brain perfus...

UNLABELLED The purpose of this study was to evaluate the effects of 2 anesthetic agents on myocardial perfusion and coronary reserve in rats under resting and stress conditions with small animal PET. METHODS Twenty-four rest/stress studies were performed in 6 rats. Each animal received all 4 possible combinations of anesthetic agents (propofol, isoflurane) and pharmacologic stress agents (dob...

BACKGROUND Left ventricular (LV) hypertrophy in aortic stenosis (AS) is characterized by reduced myocardial perfusion reserve due to coronary microvascular dysfunction. However, whether this hypoperfusion leads to tissue deoxygenation is unknown. We aimed to assess myocardial oxygenation in severe AS without obstructive coronary artery disease, and to investigate its association with myocardial...