The object of this study is to demonstrate that angled sagittal magnetic resonance imaging (MRI) enables the precise diagnosis of herniated disc and stenosis in the cervical foramen, which is not available with conventional MRI. Due to both the anatomic features of the cervical foramen and the limitations of conventional MR techniques, it has been difficult to identify disease in the lateral aspects of the spinal canal and foramen using only conventional MRI. Angled sagittal MRI oriented perpendicular to the true course of the foramina facilitates the identification of the lateral disease. A review of 43 patients, who underwent anterior cervical discectomy and interbody fusion, is presented with a herniated disc and/or stenosis in the cervical foramen. They all had undergone conventional MRI and angled sagittal MRI. Fifty levels were surgically explored for evidence of foraminal herniated disc and stenosis. The results of each test were correlated with what was found at each explored surgical level. The sensitivity, specificity, and accuracy of both examinations for making the diagnosis of foraminal herniated disc and stenosis were compared. During the diagnosis of foraminal herniated disc, the sensitivity, specificity, and accuracy of angled sagittal MRI were 96.7, 95.0, and 96.0%, respectively, compared with 56.7, 85.0, and 68.0% for conventional MRI. In making the diagnosis of foraminal stenosis, the sensitivity, specificity, and accuracy of angled sagittal MRI were 96.3, 95.7, and 96.0%, respectively, compared with 40.7, 91.3, and 66.0% for conventional MRI. In the above groups, the difference between the tests for making the diagnosis of both foraminal herniated disc and stenosis was found to be statistically significant in sensitivity and accuracy. Angled sagittal MRI was a more accurate test compared to conventional MRI for making the diagnosis of herniated disc and stenosis in the cervical foramen. It can be utilized for the precise diagnosis of foraminal herniated disc and stenosis difficult or ambiguous in conventional MRI.

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This paper presents a thermal convection–based sensor fabricated using simple microelectromechanical systems (MEMS)-based processes. This sensor can be applied to both acceleration and inclination measurements without modifying the structure. Because the operating mechanism of the accelerometer is the thermal convection of a gas medium, a simple model is proposed and developed in which the performance of the thermal convection–based accelerometer is closely associated with the Grashof number, Gr and the Prandtl number, Pr. This paper discusses the experiments that were performed by varying several parameters such as the heating power, cavity size, gas media, and air pressure. The experimental results demonstrate that an increase in the heating power, pressure, and cavity size leads to an increase in the accelerometer sensitivity. However, an increase in the pressure and/or cavity size results in a decrease in the frequency bandwidth. This paper also discusses the fact that a working-gas medium with a large thermal diffusivity and small kinematic viscosity can widen the frequency bandwidth and increase the sensitivity, respectively.