Melanie Schernthaner

Analysis of multiple sclerosis lesions using a fusion of 3.0 T FLAIR and 7.0 T SWI phase: FLAIR SWI

To improve multiple sclerosis (MS) research by introducing a new type of contrast, namely, the combination of fluid‐attenuated inversion recovery (FLAIR) data acquired at 3.0 T and 7.0 T susceptibility‐weighted imaging (SWI) phase data. The approach of this new contrast is whole‐brain coverage with 3.0 T‐FLAIR data for lesion detection—currently limited at 7.0 T due to specific absorption rate (SAR) limits—overlaid with high‐resolution, small vessel, and iron‐related 7.0 T SWI contrast. Lesion analysis in terms of penetrating veins and local iron depositions were performed.

Magnetic Resonance Imaging Analysis of the Spread of Local Anesthetic Solution after Ultrasound-guided Lateral Thoracic Paravertebral Blockade: A Volunteer Study

Background:This study was designed to examine the spread of local anesthetic (LA) via magnetic resonance imaging after a standardized ultrasound-guided thoracic paravertebral blockade. Methods:Ten volunteers were enrolled in the study. We performed ultrasound-guided single-shot paravertebral blocks with 20 ml mepivacaine 1% at the thoracic six level at both sides on two consecutive days. After each paravertebral blockade, a magnetic resonance imaging investigation was performed to investigate the three-dimensional spread of the LA. In addition, sensory spread of blockade was evaluated via pinprick testing. Results:The median (interquartile range) cranial and caudal distribution of the LA relative to the thoracic six puncture level was 1.0 (2.5) and 3.0 (0.75) [=4.0 vertebral levels] for the left and 0.5 (1.0) and 3.0 (0.75) [=3.5 vertebral levels] for the right side. Accordingly, the LA distributed more caudally than cranially. The median (interquartile range) number of sensory dermatomes which were affected by the thoracic paravertebral blockade was 9.8 (6.5) for the left and 10.7 (8.8) for the right side. The sensory distribution of thoracic paravertebral blockade was significantly larger compared with the spread of LA. Conclusions:Although the spread of LA was reproducible, the anesthetic effect was unpredictable, even with a standardized ultrasound-guided technique in volunteers. While it can be assumed that approximately 4 vertebral levels are covered by 20 ml LA, the somatic distribution of the thoracic paravertebral blockade remains unpredictable. In a significant percentage, the LA distributes into the epidural space, prevertebral, or to the contralateral side.

Value of MDCT Angiography in Developing Treatment Strategies for Critical Limb Ischemia

OBJECTIVE The purpose of this study was to assess the value of MDCT angiography in the development of strategies for the treatment of patients with critical limb ischemia. MATERIALS AND METHODS During a 12-month period, 150 patients were referred to our department for CT angiography of the peripheral arteries. All patients (n = 28) with clinical stage IV peripheral arterial occlusive disease were included in this retrospective study. The treatment reports, discharge summaries, and follow-up examinations were reviewed to ascertain the number of patients correctly treated on the basis of the CT angiographic findings. RESULTS After CT angiography, endovascular treatment was indicated for eight patients, surgical revascularization for four patients, and a combined endovascular and surgical approach for two patients. That the correct treatment decision had been made in all 14 cases was confirmed on the basis of successful endovascular or surgical revascularization. In eight patients, medical treatment was indicated, and one patient underwent amputation at the level of the thigh. Five patients were referred for complementary digital subtraction angiography, but no additional findings were made. During follow-up, three of the original 28 patients were in grave general condition and died within 7 weeks after CT angiography. Thirteen patients needed no additional treatment during the follow-up period through January 2008. After a median treatment-free interval of 381 days, 12 patients underwent additional revascularization because of clinical progression of disease. CONCLUSION MDCT angiographic findings lead to accurate recommendations for the management of critical limb ischemia. Thus CT angiography seems to be an important technique for the management of stage IV peripheral arterial occlusive disease in patients without absolute contraindications to CT angiography.

A simple classification system (the Tree flowchart) for breast MRI can reduce the number of unnecessary biopsies in MRI-only lesions

AbstractObjectivesTo assess whether using the Tree flowchart obviates unnecessary magnetic resonance imaging (MRI)-guided biopsies in breast lesions only visible on MRI.MethodsThis retrospective IRB-approved study evaluated consecutive suspicious (BI-RADS 4) breast lesions only visible on MRI that were referred to our institution for MRI-guided biopsy. All lesions were evaluated according to the Tree flowchart for breast MRI by experienced readers. The Tree flowchart is a decision rule that assigns levels of suspicion to specific combinations of diagnostic criteria. Receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic accuracy. To assess reproducibility by kappa statistics, a second reader rated a subset of 82 patients.ResultsThere were 454 patients with 469 histopathologically verified lesions included (98 malignant, 371 benign lesions). The area under the curve (AUC) of the Tree flowchart was 0.873 (95% CI: 0.839–0.901). The inter-reader agreement was almost perfect (kappa: 0.944; 95% CI 0.889–0.998). ROC analysis revealed exclusively benign lesions if the Tree node was ≤2, potentially avoiding unnecessary biopsies in 103 cases (27.8%).ConclusionsUsing the Tree flowchart in breast lesions only visible on MRI, more than 25% of biopsies could be avoided without missing any breast cancer.Key Points• The Treeflowchart may obviate >25% of unnecessary MRI-guided breast biopsies.• This decrease in MRI-guided biopsies does not cause any false-negative cases. • The Treeflowchart predicts 30.6% of malignancies with >98% specificity. • The Tree’shigh specificity aids in decision-making after benign biopsy results.

Perceptibility and Quantification of in-Stent Stenosis With Six Peripheral Arterial Stent Types in Vitro: Comparison of 16- MDCT Angiography, 64-MDCT Angiography, and MR Angiography

OBJECTIVE The purpose of this study was to evaluate and compare the perceptibility of 75% and 95% in-stent stenoses with CT angiography and MR angiography using six stent types in a phantom model. MATERIALS AND METHODS Six different stent types were placed into tubes filled with contrast agent (ioversol or gadoteric acid), and nylon cylinders (8 mm diameter) bored in the central axis (2 and 4 mm) to mimic 75% and 95% stenoses were inserted into the stents inside the tubes. CT angiography (16- and 64-MDCT scanners using three different kernels at 120 and 140 kV) and MR angiography (1.5 T) were performed. On 2-mm coronal sections, signal intensities in the stenosed stents were compared with unstenosed segments. In addition, perceptibility of the residual lumen was assessed using a subjective score. Image analysis was performed by two experienced and blinded radiologists. RESULTS Sixteen-slice CT angiography showed relative in-stent signal intensities of 72-87%, whereas 64-MDCT angiography showed relative in-stent signal intensities of 63-99%. Sixty-four-slice CT angiography showed nearly no difference between 75% and 95% stenoses in the subjective scores. The high-contrast kernel was superior to intermediate- and low-contrast kernels. MR angiography showed relative in-stent signal intensities of 57-98%. The presence of localized artifacts and resulting inhomogeneous luminal signal caused lower subjective perceptibility ratings than the objective score would suggest. CONCLUSION CT angiography was superior in the differentiation between 95% stenoses and occlusions. 64-MDCT angiography was superior to 16-MDCT (mean +/- SD, 83.0 +/- 2.9 vs 78.3 +/- 3.3; p = 0.006), especially with high-contrast kernels (89.7 +/- 2.1 vs 78.3 +/- 3.3; p = 0.001). For detection of 75% stenoses, MR angiography seems to be suitable subjectively, even though no statistical significance was found.