Myocardial perfusion reserve quantified by cardiac magnetic resonance imaging is associated with late gadolinium enhancement in hypertrophic cardiomyopathy.

Late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR) imaging has demonstrated the capability of stratifying hypertrophic cardiomyopathy (HCM). Stress perfusion test of CMR can quantify myocardial perfusion reserve (MPR), but its clinical role is not determined. The purpose of this study was to investigate the relationship between MPR and LGE in patients with HCM. A total of 61 consecutive cases underwent complete evaluation with electrocardiography and CMR [cine imaging, coronary MR angiography (MRA), and stress perfusion testing with LGE]. HCM cases were diagnosed by the Japanese conventional guideline prior to this CMR study. Mild LVH was defined as more than 13 mm in maximum LV wall thickness at end diastole on the cine imaging of the CMR. MPR was calculated as the ratio of stress/rest myocardial blood flow using an intensity curve on the stress perfusion test. Cases with ischemic heart disease were excluded from the study based on clinical history and coronary MRA. There were 37 HCM and 24 mild LVH cases (average age: 60.5 ± 10.9 vs. 64.8 ± 10.8; male: 62.2 vs. 75.0%, respectively, non-significant). MPR in HCM was lower than in LVH (1.5 ± 0.5 vs. 2.2 ± 0.9, p < 0.001) and normal subjects (2.4 ± 0.9, p < 0.001). MPR in HCM with LGE (N = 34) was lower than in HCM without LGE (N = 3) (1.4 ± 0.5 vs. 2.1 ± 0.2, p = 0.014). Multiple regression analysis verified that LGE was the strongest predictor of MPR among multiple clinical parameters, including LVH, LV dysfunction (ejection fraction < 50%), and the presence of negative T wave (p < 0.001). MPR was impaired in HCM with LGE compared with HCM without LGE. The clinical role of MPR on CMR needs to be clarified by further research.

T2*-sensitized high-resolution magnetic resonance venography using 3D-PRESTO technique.

PURPOSE: We evaluated the ability of the PRESTO (principles of echo shifting with a train of observations) technique to reveal small veins and microbleeds in the human brain. MATERIALS AND METHODS: In an experimental study, we calculated contrast-to-noise ratio (CNR) between a cerebral parenchymal phantom and human venous blood using 3 sequences of 3-dimensional (3D)-PRESTO, 3D-gradient recalled echo (GRE), and 3D-GRE echo-planar imaging (EPI). Then, we examined 7 healthy volunteers and 5 patients with venous angiomas or traumatic brain injuries using the 3D-PRESTO technique. In volunteer studies, MR venographies were reconstructed from 10-mm, 15-mm, and 20-mm thickness data using the minimum-intensity-projection (MinIP) technique. Three radiologists identified deep brain venous anatomy and counted the visible left medullary veins. In clinical studies, we evaluated the lesion conspicuity of small venous diseases and microbleeds. RESULTS: In the phantom study, 3D-PRESTO showed the highest CNR. In all volunteer studies, the deep brain venous anatomy was readily identified in the MinIP images at each thickness. The mean numbers of counted left medullary veins were 5.1 for 10 mm, 5.9 for 15 mm, and 6.7 for 20 mm in the MinIP images. The difference was significant between 10-mm and 20-mm MinIP images (P=0.02). In patient studies, abnormal small veins and microbleeds were clearly revealed. CONCLUSION: High-resolution MR venography using 3D-PRESTO technique can clearly depict small veins and microbleeds in the human brain.

Assessment of coronary arteries with total study time of less than 30 minutes by using whole-heart coronary MR angiography.

This study had institutional review board approval, and all patients gave informed consent. The purpose of this study was to prospectively evaluate the use of whole-heart three-dimensional (3D) coronary magnetic resonance (MR) angiography in patients suspected of having coronary artery disease. Whole-heart coronary MR angiography was performed in 39 patients (30 men and nine women; mean age, 63.9 years +/- 15.6 [standard deviation]) by using a steady-state free precession sequence with free breathing. Twenty patients (16 men and four women; mean age, 64.9 years +/- 11.7) also underwent conventional coronary angiography. MR angiography was successfully completed in 34 of 39 patients (87%); the average imaging time was 13.8 minutes +/- 3.8. Sensitivity and specificity of MR angiography for detecting significant stenosis were 82% (14 of 17 arteries) and 91% (39 of 43 arteries), respectively. Whole-heart coronary MR angiography with a navigator-gated steady-state sequence can enable reliable 3D visualization of the coronary arteries in patients suspected of having coronary artery disease.