Our purpose is to introduce and analyze the data quality assurance (DQA) protocol of functional magnetic resonance imaging (fMRI). A water phantom was scanned to get DQA indexes. An fMRI sequence was used to get signal noise ratio (SNR) and Drift, which was calculated from maximum difference ratio of the average signal intensity in the region of interest (ROI) of image serials. The long period application of this method demonstrated that this DQA protocol can reflect imaging performance and the state of stability of the MRI scanner. Some application experience and discussion involved in DQA were also presented here.
Algorithms ; Artifacts ; Artificial Intelligence ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; methods ; Phantoms, Imaging ; standards ; Quality Control

OBJECTIVE: To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. MATERIALS AND METHODS: Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. RESULTS: The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group < or = T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). CONCLUSION: MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.
Adult ; Aged ; *Air ; Dilatation/methods ; Female ; Humans ; Magnetic Resonance Imaging/*methods/standards ; Male ; Middle Aged ; Neoplasm Staging/*methods ; Prospective Studies ; Rectal Neoplasms/*pathology/surgery ; Rectum/*pathology ; Sensitivity and Specificity

OBJECTIVE: The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. MATERIALS AND METHODS: Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. RESULTS: The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. CONCLUSION: Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast.
Adult ; Aged ; Aged, 80 and over ; Artifacts ; Breast/pathology ; Breast Neoplasms/pathology ; Contrast Media/diagnostic use ; Diffusion Magnetic Resonance Imaging/methods/*standards ; Echo-Planar Imaging/methods/*standards ; Female ; Humans ; Image Enhancement/methods/*standards ; Middle Aged ; Observer Variation ; Retrospective Studies ; Sensitivity and Specificity ; Signal-To-Noise Ratio

OBJECTIVE: The purpose of the study was to review the current status of intra-arterial (IA) thrombolysis in Korea by conducting a retrospective analysis of the data from multiple domestic centers. MATERIALS AND METHODS: The radiologists at each participating institution were asked to fill out case report forms on all patients who had undergone IA recanalization due to acute anterior circulation ischemia. These forms included clinical, imaging and procedure-related information. A central reader analyzed the CT/MR and angiographic results. The rates of successful recanalization, hemorrhagic transformation and functional outcome were obtained. The univariate analyses were performed together with the multivariate analysis. RESULTS: We analyzed the data from 163 patients, and they had been treated at seven institutes. The initial imaging modalities were CT for 46 patients (28%), MR for 63 (39%), and both for 54 (33%). Various mechanical treatment methods were applied together in 50% of the patients. Radiologically significant hemorrhage was noted in 20/155 patients (13%). We found various factors that influenced the recanalization rate and the occurrence of significant hemorrhagic transformations. The favorable outcome rate, reported as modified Rankin Scale < or = 2, was 40%, and the mortality rate was 11%. The factors that predicted a poor functional outcome were old age (p = 0.01), initially severe neurological symptoms (p < 0.0001), MR findings of a wide distribution of lesions (p = 0.001), involvement of the basal ganglia (p = 0.01), performance of procedures after working hours (p = 0.01), failure of recanalization (p = 0.003), contrast extravasation after the procedure (p = 0.007) and significant hemorrhagic transformation (p = 0.002). The subsequent multivariate analysis failed to show any statistically significant variable. CONCLUSION: There was a trend toward increased dependency on MR imaging during the initial evaluation and increased usage of combined pharmacologic/mechanical thrombolysis. The imaging and clinical outcome results of this study were comparable to those of the previous major thrombolytic trials.
Acute Disease ; Cerebral Angiography ; Cerebral Infarction/diagnosis/*drug therapy ; Female ; Fibrinolytic Agents/*administration & dosage ; Humans ; Injections, Intra-Arterial ; Logistic Models ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Retrospective Studies ; Thrombolytic Therapy/*methods/standards ; Tomography, X-Ray Computed ; Treatment Outcome