Birgit Simon

Improved in vivo detection of cortical lesions in multiple sclerosis using double inversion recovery MR imaging at 3 Tesla

ObjectiveTo investigate the impact of a higher magnetic field strength of 3 Tesla (T) on the detection rate of cortical lesions in multiple sclerosis (MS) patients, in particular using a dedicated double inversion recovery (DIR) pulse sequence.MethodsThirty-four patients with clinically isolated syndromes or definite MS were included. All patients underwent magnetic resonance imaging (MRI) at 1.5 T and 3 T, including T2-weighted turbo spin echo (TSE), fluid-attenuated inversion recovery (FLAIR) and DIR sequences. All images were analysed for focal lesions categorised according to their anatomical location.ResultsThe total number of detected lesions was higher at 3 T across all pulse sequences. We observed significantly higher numbers of lesions involving the cortex at 3 T using a DIR sequence. DIR at 3 T showed 192% more pure intracortical (p < 0.001) and 30% more mixed grey matter-white matter lesions (p = 0.008). No significant increase in cortical lesions could be detected on the FLAIR and T2-weighted images. Using the T2-weighted and FLAIR sequences, significantly more lesions could be detected at 3 T in the infratentorial, periventricular and juxtacortical white matter.ConclusionDIR brain MR imaging at 3 T substantially improves the sensitivity of the detection of cortical lesions compared with the standard magnetic field strength of 1.5 T.

Does high field MRI allow an earlier diagnosis of multiple sclerosis

BackgroundHigh field magnetic resonance imaging (MRI) provides higher lesion load measurements in patients presenting with clinically isolated syndromes (CIS) suggestive of demyelination and has impact upon the classification of these syndromes and potentially, the diagnosis of multiple sclerosis (MS).PurposeTo investigate whether high field MRI can provide an earlier diagnosis of definite MS within the International Panel (IP) and Swanton criteria.MethodsForty patients presenting with CIS suggestive of MS were included. All patients received multi-sequence MRI at 1.5 Tesla (T) and 3T as well as a neurological assessment at baseline. Follow-up visits including MRI at both field strengths and neurological examinations were scheduled 3–4 and 6–7 months after the first clinical event. Based on MRI and clinical findings, fulfilled IP criteria as well as Swanton criteria were analysed.ResultsAt baseline, the higher detection rate of inflammatory lesions using high field MRI leads to higher classifications according to the Swanton criteria in 15 % of the patients. One additional patient was diagnosed with dissemination in space according to Swanton and IP criteria. During follow-up, an earlier diagnosis of definite MS could not be accomplished, neither according to the IP nor to the Swanton criteria.ConclusionAlthough high field MRI shows a higher detection rate of inflammatory brain lesion in CIS and MS patients with an influence according to MRI criteria, this influence does not lead to an earlier diagnosis of lesion dissemination in time and therefore definite MS.

MRI-guided breast biopsy: influence of choice of vacuum biopsy system on the mode of biopsy of MRI-only suspicious breast lesions.

OBJECTIVE The purpose of this study was to evaluate two systems of MRI-guided vacuum-assisted biopsy and to investigate the influence of the choice of system on the choice of biopsy mode in the care of patients with lesions found only at MRI. MATERIALS AND METHODS Over a period of 3 years, a total 349 patients underwent MRI-guided tissue sampling of 475 lesions found only at MRI. The lesions were sampled by needle localization plus excisional biopsy or by vacuum-assisted biopsy. Two different systems were used for MRI-guided vacuum-assisted biopsy. During the first half of the study period, a handheld system was used, and during the second half, a console system was used. The procedural advantages and disadvantages, size of lesions biopsied, and time needed for vacuum-assisted biopsy were recorded. The distribution of the type of intervention (needle localization or vacuum-assisted biopsy) used to manage MRI-only lesions during the two study periods also was assessed. RESULTS The average diameter of lesions sampled with vacuum-assisted biopsy was 19.2 mm with the handheld system and 10.4 mm with the console system (p < 0.039). The average biopsy time was 69 minutes for the handheld system and 39 minutes for the console system (p < 0.005). Of the total of 170 MRI-only lesions biopsied with the handheld system, 121 (71%) were sampled by localization and 49 (29%) by vacuum-assisted biopsy. Of the total 305 MRI-only lesions biopsied with the console system, 38 (12%) were sampled by localization and 267 (88%) by vacuum-assisted biopsy. CONCLUSION Because of the procedural advantages of use of the console-based system, smaller lesions were biopsied in less time and with higher operator confidence. This result translated into a major shift in the care of patients with MRI-only lesions away from lesion localization toward increased use of MRI-guided vacuum-assisted biopsy.

Transrenal Ureter Occlusion with an Amplatzer Vascular Plug

The Amplatzer vascular plug has been used as an embolic device in a variety of cardiovascular interventions. The present report describes successful transrenal ureter occlusion with an Amplatzer plug inserted into an excised latex cover. The procedure led to immediate ureter occlusion in a patient with vesicovaginal fistula. Further investigation into the use of this technique for ureteral occlusion is warranted.

Diffusion-weighted Whole-body MRI at 3 Tesla for the Detection and Discrimination of Pulmonary Tumors

Objective: To evaluate diffusion-weighted whole-body MRI with background body signal suppression (DWIBS) at 3.0 T for pulmonary lesion detection and characterization. Materials and Methods: 19 patients with 25 pulmonary lesions were examined with DWIBS using 2 b-values (b = 0 and 1000 s/mm2) and partly additionally with DWIBS using 3 b-values (b = 0, 50, 1000 s/mm2). DWIBS was compared to FDG PET. For characterization of hyperintense lesions by DWIBS, Lesion-to-Spinal cord Ratio (LSR) and apparent diffusion coefficient ADC were analyzed. From repeated measurements, the Coefficient of Variation (CV) was calculated. From 3-b-value data, the ADC(0,1000) and ADC(50,1000) values were compared in order to assess perfusion influences. Results: Sensitivity and specificity of detecting malignant lesions were comparable for DWIBS and FDG PET. Malignant compared to benign lesions had lower ADC(0,1000) and higher LSR values. CV of LSR was more than a factor of 8 higher than CV of ADC(0,1000) (23.9% vs 2.9%, P = 0.012). Perfusion effects were largest for metastases, medium for adenocarcinoma and benign lesions, and lowest for squamous cell carcinoma. Conclusion: DWIBS at 3.0 T is appropriate for lesion detection and characterization. ADC analysis is superior to signal intensity ratio determination with respect to repeatability. An analysis of perfusion influences provides additional information.

Extraretinal Induced Visual Sensations during IMRT of the Brain

BACKGROUND We observed visual sensations (VSs) in patients undergoing intensity modulated radiotherapy (IMRT) of the brain without the beam passing through ocular structures. We analyzed this phenomenon especially with regards to reproducibility, and origin. METHODS AND FINDINGS Analyzed were ten consecutive patients (aged 41-71 years) with glioblastoma multiforme who received pulsed IMRT (total dose 60Gy) with helical tomotherapy (TT). A megavolt-CT (MVCT) was performed daily before treatment. VSs were reported and recorded using a triggered event recorder. The frequency of VSs was calculated and VSs were correlated with beam direction and couch position. Subjective patient perception was plotted on an 8x8 visual field (VF) matrix. Distance to the orbital roof (OR) from the first beam causing a VS was calculated from the Dicom radiation therapy data and MVCT data. During 175 treatment sessions (average 17.5 per patient) 5959 VSs were recorded and analyzed. VSs occurred only during the treatment session not during the MVCTs. Plotting events over time revealed patient-specific patterns. The average cranio-caudad extension of VS-inducing area was 63.4mm (range 43.24-92.1mm). The maximum distance between the first VS and the OR was 56.1mm so that direct interaction with the retina is unlikely. Data on subjective visual perception showed that VSs occurred mainly in the upper right and left quadrants of the VF. Within the visual pathways the highest probability for origin of VSs was seen in the optic chiasm and the optic tract (22%). CONCLUSIONS There is clear evidence that interaction of photon irradiation with neuronal structures distant from the eye can lead to VSs.

Appearance of extraosseous pelvic Ewing sarcoma on triphasic bone scan.

A 24-year-old man with extraosseous Ewing sarcoma in the pelvis underwent a triphasic bone scintigraphy to rule out bone metastases and local bone infiltration before chemotherapy. The bone scintigraphy showed tracer uptake in the tumor in all 3 phases.