Objective To investigate the clinical features and magnetic resonance imaging (MRI)findings of patients with Hirayama disease simply presenting proximal upper extremity muscular atrophy.Methods Three patients with Hirayama disease simply presenting proximal upper extremity muscular atrophy received cervical spine MRI on neutral and flexion position. The relationship between MRI findings and their clinical symptoms were analyzed. The outcomes were compared with those of 43 patients who were diagnosed as Hirayama disease with muscular atrophy at the hand and forearm. Results 1) Clinical features:three patients were young men. The disease was characterized by unilateral weakness and atrophy of the proximal upper limbs, such as pectoralis major muscle, deltoid muscle, and biceps brachii muscle. Electromyogram (EMG) showed bilateral upper extremities neurogenic damage. 2) Cervical spine MRI findings:cervical spine kyphosis without spinal cord compression was found on neutral position. On flexion position,anterior shifting of C3-C5 cervical cord and the posterior wall of dural sac were found; C4-C5 cervical cord was compressed by vertebral body or intervertebral disc or dural sac. Engorged posterior internal vertebral venous plexus were observed in epidural space. In the 43 patients who were diagnosed Hirayama disease with muscular atrophy at the hand and forearm, similar MRI findings were found, while cervical cords compression were at C6-C7 level. Conclusion Hirayama disease could present as proximal upper extremity muscular atrophy and weakness, such as pectoralis major muscle, deltoid muscle, and biceps brachii muscle.Neglecting of this will result in diagnostic errors or missed diagnosis. Flexion position MRI is an important base of early diagnosis of Hirayama disease.

Objective:To investigate the reproducibility of whole-heart and volume-targeted balanced steady-state free precession (bSSFP) non-contrast MR coronary angiography (CMRA) for displaying coronary trunks.Methods:From February and September 2021, the whole-heart and volume-targeted CMRA examinations of 58 volunteers were prospectively and consecutively acquired in The First Affiliated Hospital of Fujian Medical University. Each volunteer underwent CMRA twice within a week. The subjective score, vessel-to-myocardium ratio (VMR), vessel-to-fat ratio (VFR), signal-noise ratio (SNR), and coronary corresponding coordinate was analyzed and extracted. Inter-observer, intra-observer and inter-scan consistency were evaluated by intraclass correlation coefficient (ICC), Bland-Altman analysis, Hausdorff Distance (HD), and Dice Similarity Coefficient (DSC).Results:The inter-observer and intra-observer consistencies of subjective scores, VMR, and VFR of the whole-heart and volume-targeted coronary artery images were excellent (ICC>0.76, P<0.001). The inter-scan VFR consistencies of RCA, LM, and LCX of whole-heart coronary scans were moderate (ICC=0.235, 0.264, 0.380, all P<0.05), while the consistencies of the remaining variables were good, (all ICCs>0.49, P<0.001). Bland-Altman method showed that most VMR, VFR, and SNR of two CMRA imaging were within the 95% limits of agreement. Whole-heart CMRA inter-and intra-observer mean HD was 1.79 (1.35, 3.25), 1.68 (1.09, 4.10), mean DSC was 0.96±0.04, 0.97±0.03. Volume-targeted CMRA inter-and intra-observer mean HD were 1.74 (1.63, 3.11), 1.74 (1.63, 1.98), and the mean DSC was 0.91±0.10, 0.95±0.05. The subjective score of raw images of the total artery trunk of volume-targeted CMRA [3.86 (3.68,4.00) vs. 3.80 (3.58,3.96) ], VMR [1.45 (1.27,1.58) vs. 1.22 (1.13,1.41) ], and VFR [7.36 (6.44,8.60) vs. 5.97 (4.97,6.64) ] were better than those of whole-heart CMRA (all P<0.05). The overall subjective score of whole-heart CMRA coronary trunk curved projection reformation was better than volume-targeted CMRA [3.75 (3.57, 3.88) vs. 3.63 (3.44, 3.71)] ( P<0.001). Conclusions:Whole-heart and volume-targeted bSSFP non-contrast CMRA represent good reproducibility and image quality in the main coronary artery of healthy volunteers. Both of the two methods have their advantages and complement each other.