Completion of Target Vessel Stenting After FEVAR via Snare Technique in a Patient with Tortuous Right Renal Artery.

Target vessel catheterization remains challenging in patients with complex anatomies. Fenestrated endovascular aneurysm repair (FEVAR) is an established technique to treat aortic aneurysms. In this case report, we treated a juxtarenal aneurysm using FEVAR. Initial attempts to complete the target vessel stenting were unsuccessful because of an unfavorable orifice and tortuosity of the right renal artery. The completion of FEVAR was achieved with a bifemoral approach using a snare system, which aligned the tip of a steerable sheath at the level of the fenestration for the right renal artery to create a stable condition. Control angiography and computed tomography confirmed a successful stenting of the target vessel and the sealing of the fenestration without an endoleak.

Towards fast whole-body PET/MR: Investigation of PET image quality versus reduced PET acquisition times.

PURPOSE: The trend towards faster acquisition protocols in whole-body positron emission tomography/magnetic resonance (PET/MR) arises the question of whether short PET data acquisition protocols in a whole-body multi-station context allow for reduced PET acquisition times while providing adequate PET image quality and accurate quantification parameters. The study goal is to investigate how reducing PET acquisition times affects PET image quality and quantification in whole-body PET/MR in patients with oncologic findings. METHODS: Fifty-one patients with different oncologic findings underwent a clinical whole-body 18F-Fluorodeoxyglucose PET/MR examination. PET data was reconstructed with 4, 3, 2, and 1 min/bed time intervals for each patient to simulate the effect of reduced PET acquisition times. The 4-minute PET reconstructions served as reference standard. All whole-body PET data sets were analyzed regarding image quality, lesion detectability, PET quantification and standardized uptake values. RESULTS: A total of 91 lesions were detected in the 4-minute PET reconstructions. The same number of congruent lesions was also noticed in the 3 and 2 minutes-per-bed (mpb) reconstructed images. A total of 2 lesions in 2 patients was not detected in the 1 minute PET data reconstructions due to poor image quality. Image noise in the blood pool increased from 22.2% (4 mpb) to 42.1% (1 mpb). Signal-to-noise ratio declined with shorter timeframes from 13.1 (4 mpb) to 9.3 (1 mpb). SUVmean and SUVmax showed no significant changes between 4 and 1 mpb reconstructed timeframes. CONCLUSIONS: Reconstruction of PET data with different time intervals has shown that 2 minutes acquisition time per bed position instead of 4 minutes is sufficient to provide accurate lesion detection and adequate image quality in a clinical setting, despite the trends to lower image quality with shorter PET acquisition times. This provides latitude for potential reduction of PET acquisition times in fast PET/MR whole-body examinations.

Age-related apparent diffusion coefficients of lumbar vertebrae in healthy children at 1.5 T.

BACKGROUND: Diffusion-weighted magnetic resonance imaging with apparent diffusion coefficient (ADC) calculation is important for detecting bone marrow pathologies. OBJECTIVE: To investigate age-related differences of lumbar vertebral body ADC to establish normal values for healthy children. MATERIALS AND METHODS: Forty-nine healthy children without any history of oncological or hematological diseases (10.2±4.7 years, range: 0-20 years) were included in this retrospective study. All magnetic resonance imaging (MRI) examinations were performed at 1.5 T and with similar scan parameters. The diffusion-weighted sequences were performed with b values of 50, 400 and 800 s/mm2. ADC values were measured by placing regions of interest at three different levels within each lumbar vertebral body (L1 to L5). ADC values were analyzed for different age groups (0-2 years, 3-6 years, 7-11 years, 12-14 years, 15-20 years), for each vertebral and intravertebral level. RESULTS: The mean ADC of the whole study group was 0.60±0.09 × 10-3 mm2/s. Children between the ages of 12 and 14 years had significantly higher ADC compared to the other age groups (P≤0.0003). ADC values were significantly higher in the 1st lumbar vertebral body compared to the other levels of the lumbar spine (P<0.005) with the exception of L5, and in the upper third of the vertebral bodies compared to the middle or lower thirds (P≤0.003). CONCLUSION: The age-, vertebral- and intravertebral level-dependent differences in ADC suggest a varying composition and cellularity in different age groups and in different locations.

Simultaneous multiparametric PET/MRI for the assessment of therapeutic response to chemotherapy or concurrent chemoradiotherapy of cervical cancer patients: Preliminary results.

PURPOSE: To assess the response to initial treatment strategies of cervical cancer using multiparametric-PET/MRI. MATERIAL AND METHODS: PET/MR-derived morphological (tumor size), functional (DWI, DCE-MRI) and metabolic (18F-FDG PET) parameters were acquired in pre- and posttreatment examinations of 8 patients. Besides RECIST- and PERCIST-criteria, functional quantitative parameters were used to assess therapeutic response. RESULTS: RECIST- and PERCIST-response criteria demonstrated high correlations for the differentiation between therapy-responders and non-responders, which was additionally reflected by functional (DWI, DCE-MRI) quantitative imaging parameters. CONCLUSION: Multiparametric-PET/MRI bears the potential of a more comprehensive response assessment of initial treatment strategies in cervical cancer patients.

Risk Stratification of Equivocal Lesions on Multiparametric Magnetic Resonance Imaging of the Prostate.

PURPOSE: We systematically analyzed the records of patients with PI-RADS™ (Prostate Imaging Reporting and Data System) 3 lesions, which are called equivocal according to PI-RADS version 2, using prostate multiparametric magnetic resonance imaging and magnetic resonance imaging targeted biopsies. Systematic transrectal ultrasound guided biopsies served as the reference standard. MATERIALS AND METHODS: A total of 120 consecutive patients were retrospectively included in the study. In these patients the overall PI-RADS score was 3 after 3 Tesla T2-weighted imaging, diffusion weighted imaging and dynamic contrast enhanced multiparametric magnetic resonance imaging as well as subsequent targeted magnetic resonance imaging/ultrasound fusion guided biopsies plus systematic 12-core transrectal ultrasound guided biopsies. The study end points were the prostate cancer detection rate, the Gleason score distribution, the prostate cancer location and risk stratification by subgroup analyses. RESULTS: Prostate cancer was detected in 13 of 118 patients for a detection rate of 11%, including 5 patients (4.2%) with a Gleason score of 3 + 4 = 7 or greater. Three of the 212 lesions (1.4%) in the transition zone and 6 of the 64 (9.4%) in the peripheral zone were positive for prostate cancer. Multiparametric magnetic resonance imaging revealed patterns of peripheral prostatitis combined with diffuse stromal hyperplasia in 54% of the patients with prostate cancer. Prostate volume was significantly lower in patients with prostate cancer (p = 0.015) but differences in prostate specific antigen levels were not statistically significant (p = 0.87). Prostate specific antigen density was higher in patients with prostate cancer (0.19 vs 0.12 ng/ml/ml). CONCLUSIONS: Low grade prostate cancer (Gleason score 3 + 3 = 6) can develop in patients with an overall PI-RADS score of 3. Prostate cancer with a Gleason score of 3 + 4 = 7 or greater can be detected by multiparametric magnetic resonance imaging with a high degree of certainty. Gleason score 4 + 3 = 7 or greater prostate cancer is unlikely in PI-RADS 3 lesions. Therefore, these patients should primarily undergo followup multiparametric magnetic resonance imaging. In patients with a combination of multiparametric magnetic resonance imaging aspects of extensive prostatitis and diffuse stromal hyperplasia low prostate volume and/or high prostate specific antigen density biopsy might be considered.