Background and Purpose
Dementia with Lewy bodies (DLB) is the second most prevalent cause of degenerative dementia next to Alzheimer's disease (AD). Though current DLB diagnostic criteria employ several indicative biomarkers, relative preservation of the medial temporal lobe as revealed by structural MRI suffers from low sensitivity and specificity, making them unreliable as sole supporting biomarkers. In this study, we investigated how a deep learning approach would be able to differentiate DLB from AD with structural MRI data.
Methods
Two‐hundred and eight patients (101 DLB, 69 AD, and 38 controls) participated in this retrospective study. Gray matter images were extracted using voxel‐based morphometry (VBM). In order to compare the conventional statistical analysis with deep‐learning feature extraction, we built a classification model for DLB and AD with a residual neural network (ResNet) type of convolutional neural network architecture, which is one of the deep learning models. The anatomically standardized gray matter images extracted in the same way as for the VBM process were used as inputs, and the classification performance achieved by our model was evaluated.
Results
Conventional statistical analysis detected no significant atrophy other than fine differences on the middle temporal pole and hippocampal regions. The feature extracted by the deep learning method differentiated DLB from AD with 79.15% accuracy compared to the 68.41% of the conventional method.
Conclusions
Our results confirmed that the deep learning method with gray matter images can detect fine differences between DLB and AD that may be underestimated by the conventional method.
With serial measurement of blood sugar levels during surgery in three patients with solitary insulinoma, we confirmed the location, then later, the complete elimination of the insulin-secreting tumor. Following vigorous massage of the tumor, blood sugar levels decreased while the levels progressively increased within 20 min following removal of the tumor. Subsequent measurement of simultaneous plasma insulin levels provided further confirmation. Plasma levels of insulin increased in accordance with massage of the tumor. Prior to removal of the tumor, the levels progressively decreased to less than the preoperative levels. For success in detecting slight changes in blood sugar levels secondary to increase or decrease of insulin secretion during surgery for insulinoma, (1) controlled infusion of glucose to keep blood sugar levels around 80 mg/dl and (2) frequent rapid determination of blood sugar levels are considered to be important.
In an attempt to elucidate changes in endocrine functions of the pancreas associated with radical pancreatectomy for periampullary cancer, plasma levels of insulin (IRI) and pancreatic glucagon (IRG) were measured during arginine infusion in ten patients with periampullary cancer both before and after pancreatoduodenectomy. The response of plasma IRI to arginine which was impaired before the surgery showed further impairment after the surgery. This finding is consistent with the previous results obtained in such patients by oral glucose tolerance testing. Also, the response of plasma IRG was subnormal preoperatively and was found to be impaired postoperatively. Both maximum and integrated secretion of IRG during arginine infusion decreased after the surgery in all instances. From these findings, it is concluded that pancreatoduodenectomy aggravates the already disordered pancreatic endocrine functions, as indicated by arginine infusion in patients with periampullary cancer.
The effect of a bolus intravenous administration of secretin (2.0 U/kg) on resting lower esophageal sphincter pressure (LESP) was investigated in seven patients with esophageal achalasia. Basal LESP before secretin injection in the patients was 60.1 +/- 3.4 mmHg (Mean +/- SEM), which was significantly higher than 26.9 +/- 2.5 mmHg in normal controls consisting of eight healthy volunteers. LESP significantly decreased within 1 min after the injection both in the patients and the controls. The maximum pressure change from each basal LESP was 31.2 +/- 5.2 mmHg in the patients, which was significantly greater than 12.1 +/- 1.8 mmHg in the controls. The effect of secretin disappeared within 5 min in the controls. The effect in the patients, however, lasted throughout the investigation time of 30 min. It is concluded that secretin has a long-acting effect on muscular relaxation of the lower esophageal sphincter in esophageal achalsia patients.
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