Purpose: To understand the effects of datasets with various parameters on pretrained network performance, the generalization capacity of the artificial neural network for myelin water imaging (ANN-MWI) is explored by testing datasets with various scan protocols (i.e., resolution and refocusing RF pulse shape) and types of disorders (i.e., neuromyelitis optica and edema). Materials and Methods: ANN-MWI was trained to generate a T2 distribution, from which the myelin water fraction value was measured. The training and test datasets were acquired from healthy controls and multiple sclerosis patients using a multiecho gradient and spin-echo sequence with the same scan protocols. To test the generalization capacity of ANN-MWI, datasets with different settings were utilized.The datasets were acquired or generated with different resolutions, refocusing pulse shape, and types of disorders. For all datasets, the evaluation was performed in a white matter mask by calculating the normalized root-mean-squared error (NRMSE) between the results from the conventional method and ANN-MWI. Additionally, for the patient datasets, the NRMSE was calculated in each lesion mask. Results: The results of ANN-MWI showed high reliability in generating myelin water fraction maps from the datasets with different resolutions. However, the increased errors were reported for the datasets with different refocusing pulse shapes and disorder types. Specifically, the region of lesions in edema patients reported high NRMSEs. These increased errors indicate the dependency of ANN-MWI on refocusing pulse flip angles and T 2 characteristics. Conclusion This study proposes information about the generalization accuracy of a trained network when applying deep learning to processing myelin water imaging.

PURPOSE: The characteristics of hypoparathyroidism in patients with Hashimoto thyroiditis (HT) after total thyroidectomy are not well established. The aim of this study was to investigate the relationship between hypoparathyroidism and loss of parathyroid glands in patients with or without HT who underwent total thyroidectomy. METHODS: Patients who underwent total thyroidectomy were divided into two groups; with HT (n=166) and without HT (n=526). Clinicopathologic characteristics were compared between the two groups. RESULTS: The mean numbers of parathyroid glands in specimens were significantly smaller in the with HT group than in the without HT group (0.34+/-0.51 vs. 0.42+/-0.58, P=0.003). The rate of transient hypoparathyroidism was significantly higher in the with HT group than in the without HT group (51.8% vs. 34.6%, P=0.000). Serum total calcium levels in patients who experienced transient hypoparathyroidism did not differ significantly between groups (P=0.335). The incidence of transient hypoparathyroidism of patients who preserved all four parathyroid glands or sacrificed one parathyroid gland was higher in the with HT group than in the without HT group, although that of patients who sacrificed two or more parathyroid glands was similar between groups. The incidence of permanent hypoparathyroidism in the two groups did not differ (P=0.546). CONCLUSION: Patients with HT had a higher rate of transient hypoparathyroidism after total thyroidectomy, particularly patients who preserved all four or three parathyroid glands. It is likely that the blood supply to the parathyroid gland might be vulnerable in patients with HT. Therefore, even though all parathyroid glands were preserved, careful monitoring of hypoparathyroidism is necessary after total thyroidectomy in patients with HT.
Calcium ; Hashimoto Disease* ; Humans ; Hypoparathyroidism* ; Incidence ; Parathyroid Glands ; Thyroidectomy*