ABSTRACT
Background: Carpal tunnel syndrome (CTS) is diagnosed based on neurological, electrophysiology, and radiological findings. Due to the technical development of magnetic resonance imaging (MRI), the median nerve is evaluated with several MRI protocols. However, diffusion tensor imaging (DTI) combined with a dual-echo steady-state (DESS) protocol is not frequently used to evaluate the median nerve of CTS. This study aimed to evaluate the median nerve in the carpal tunnel using DTI combined with a DESS protocol. Methods: Five healthy volunteers and seven patients with CTS were enrolled. The patients underwent MRI for CTS pre- and post-operatively. The median nerve was evaluated using a 3-T MRI scanner. The parameters of the DESS protocol were as follows: Repetition time (TR)/echo time (TE) = 10.83/3.32 ms, slice thickness = 0.45 mm, field of view (FoV) = 350 × 253 × 350 mm, and 3D voxel size = 0.5 × 0.5 ×0.4 mm. The parameters of the DTI sequence were as follows: TR/TE = 4000/86 ms, slice thickness = 3 mm, FoV = 160 × 993 × 90 mm, 3D voxel size = 1.2 × 1.2 ×3.0 mm, and b value = 0.1000 s/mm2. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of the median nerve were statistically analyzed. Statistical significance was set at P< 0.05. Results: The FA value of healthy volunteers was 0.576 ± 0.058, while those of the patients were 0.357 ± 0.094 and 0.395 ± 0.062 pre-and post-operatively, respectively. Statistically significant differences were identified between the FA values of healthy volunteers and pre-operative/post-operative patients. The ADC values of healthy volunteers and pre-operative patients were 0.931 ± 0.096 and 1.26 ± 0.282 (10-3 mm2/s), respectively (P< 0.05). Conclusion: This MRI protocol may be useful for evaluating the median nerve in the carpal tunnel.
ABSTRACT
BACKGROUND/AIM: Stereotactic radiosurgery (SRS)-used for brain metastases (BMs) with a tumor diameter of ≤2 cm-has a high local control rate, however, it can cause symptomatic radiation-induced brain necrosis. Hypofractionated stereotactic radiation therapy (HFSRT) is not commonly used for such lesions and its effectiveness remains unknown. Herein, the efficacy of 30 Gy 5-fraction HFSRT for treating BMs of <2 cm was retrospectively evaluated. PATIENTS AND METHODS: Patients who received HFSRT and had a gross tumor volume (GTV) of ≤2 cm in maximum diameter were included in the study (49 patients; 179 BMs; median follow-up period, 11.9 months). RESULTS: The mean GTV Peripheral Dose (D95) was 36.2 Gy. The local control (LC) rates at 1 and 2 years were 93.0% and 81.5%, respectively, for all lesions. The 1-year LC rates were 93.6% and 92.0% for ≤1.0-cm and 1.0-2.0-cm lesions, respectively. Multivariate analysis revealed that the only significant difference was in GTV maximal tumor diameter (HR=1.961, p=0.0002). Notably, only one patient had asymptomatic radiation necrosis. CONCLUSION: Owing to the high toxicity of SRS, 5-fraction HFSRT can be an effective treatment strategy for BMs of <2 cm.
Subject(s)
Brain Neoplasms , Radiation Injuries , Radiosurgery , Humans , Radiosurgery/adverse effects , Retrospective Studies , Brain Neoplasms/pathology , Treatment Outcome , Radiation Injuries/etiology , Necrosis/etiologyABSTRACT
BACKGROUND: Determining stroke subtypes on initial clinical evaluation is a prerequisite for the selection of appropriate initial treatment. Although diffusion-weighted imaging (DWI) is a powerful tool for detection of acute cerebral infarction, its diagnostic accuracy is not always sufficient particularly in the hyperacute phase. METHODS: Patients admitted within 2 weeks from the symptom onset with the diagnosis of acute ischemic strokes were analyzed with thin-section iso-voxel DWI, namely 3-dimension DWI (3D-DWI), to obtain axial, coronal, and sagittal sections in order to elucidate stroke characteristics. In this case series, we introduce the effectiveness of 3D-DWI. RESULTS: 3D-DWI uncovered stroke subtypes and distribution more precisely compared with conventional DWI. While previous studies indicated the utility of thin section DWI in detecting infratentrial infarctions, 3D-DWI is beneficial for the detection of not only infratentrial but also supratentorial lesions. Furthermore, since both 3D-DWI and magnetic resonance angiography (MRA) are multiplanar reconstruction images, the fusion image of 3D-DWI with MRA is available, enabling cross-reference of spatial cerebrovascular configuration and ischemic lesions. CONCLUSIONS: 3D-DWI is applicable to standard 1.5 T MRI by slight modification of data acquisition protocols, and becomes a key modality to solve the diagnostic puzzle of acute ischemic strokes.