Value of MRI imaging prior to a kyphoplasty for osteoporotic insufficiency fractures.

Previous studies have shown the safety and effectiveness of balloon kyphoplasty in the treatment of osteoporotic vertebral compression fractures (OVCFs). MRI and particularly the short tau inversion recovery (STIR) sequence are very sensitive for detecting vertebral edema as a result of fresh fractures or micro-fractures. Therefore, it has a great therapeutic relevance in differentiating vertebral deformities seen by conventional X-ray and CT scans. Although an MRI scan is expensive, to my knowledge no study has evaluated the benefits of preoperative MRI in evaluating a therapeutic plan for kyphoplasty. This is a prospective study evaluating the benefit of a preoperative MRI scan regarding changes of kyphoplasty therapy. Twenty-eight patients were included in this study. Twenty-four patients were treated by balloon kyphoplasty, in a total of 40 vertebral bodies. The mean age was 73 years. All patients suffered from OVCFs. As a first step, all patients got a CT scan. The individual therapeutic plan was then defined by the patients' history, complaints and the results of the CT scan. As far as all criteria for kyphoplasty were fulfilled, an MRI examination including the STIR sequences was performed preoperatively. The number of times a change was made in therapy as a result from the additional information from the MRI was then evaluated. By performing a preoperatively MRI examination, the therapy plan was changed in 16 out of 28 (57%) patients. Eight patients underwent additional levels of kyphoplasty at the same procedure. In five patients, lesions were found to be old fractures and therefore were not treated operatively. Two of these patients received no kyphoplasty at all. Another patient only a part of the originally intended levels was treated. The other two cases received a kyphoplasty at different vertebral levels, as these vertebral bodies showed signs of an acute fracture in the MRI scan. Additionally, an incidental diagnosis of carcinoma of the kidney was made in two patients. Kyphoplasty was deferred and they were referred for further evaluation. One patient was found to have an aortic aneurysm. Kyphoplasty was performed and after that the patient was referred in order to treat the aneurysm. This study confirms the diagnostic benefits of an MRI scan before performing a kyphoplasty. For 16 out of 28 patients, the therapeutic plan was changed because of the information obtained by preoperative MRI. Preoperative MRI helped to generate the correct surgical strategy, by demonstrating the correct location of injury and by detecting concomitant diseases.

Computer-aided detection of pulmonary nodules: influence of nodule characteristics on detection performance.

AIM: To evaluate prospectively the influence of pulmonary nodule characteristics on detection performances of a computer-aided diagnosis (CAD) tool and experienced chest radiologists using multislice CT (MSCT). MATERIALS AND METHODS: MSCT scans of 20 consecutive patients were evaluated by a CAD system and two independent chest radiologists for presence of pulmonary nodules. Nodule size, position, margin, matrix characteristics, vascular and pleural attachments and reader confidence were recorded and data compared with an independent standard of reference. Statistical analysis for predictors influencing nodule detection or reader performance included chi-squared, retrograde stepwise conditional logistic regression with odds ratios and nodule detection proportion estimates (DPE), and ROC analysis. RESULTS: For 135 nodules, detection rates for CAD and readers were 76.3, 52.6 and 52.6%, respectively; false-positive rates were 0.55, 0.25 and 0.15 per examination, respectively. In consensus with CAD the reader detection rate increased to 93.3%, and the false-positive rate dropped to 0.1/scan. DPEs for nodules < or = 5 mm were significantly higher for ICAD than for the readers (p < 0.05). Absence of vascular attachment was the only significant predictor of nodule detection by CAD (p = 0.0006-0.008). There were no predictors of nodule detection for reader consensus with CAD. In contrast, vascular attachment predicted nodule detection by the readers (p = 0.0001-0.003). Reader sensitivity was higher for nodules with vascular attachment than for unattached nodules (sensitivities 0.768 and 0.369; 95% confidence intervals = 0.651-0.861 and 0.253-0.498, respectively). CONCLUSION: CAD increases nodule detection rates, decreases false-positive rates and compensates for deficient reader performance in detection of smallest lesions and of nodules without vascular attachment.