Percutaneous Large-Bore Pulmonary Thrombectomy with the FlowTriever Device: Initial Experience in Intermediate-High and High-Risk Patients.

OBJECTIVES: This retrospective cohort study investigates outcomes of patients with intermediate-high and high-risk pulmonary embolism (PE) who were treated with transfemoral mechanical thrombectomy (MT) using the large-bore Inari FlowTriever aspiration catheter system. MATERIAL AND METHODS: Twenty-seven patients (mean age 56.1 ± 15.3 years) treated with MT for PE between 04/2021 and 11/2021 were reviewed. Risk stratification was performed according to European Society of Cardiology (ESC) guidelines. Clinical and hemodynamic characteristics before and after the procedure were compared with the paired Student's t test, and duration of hospital stay was analyzed with the Kaplan-Meier estimator. Procedure-related adverse advents were assessed. RESULTS: Of 27 patients treated, 18 were classified as high risk. Mean right-to-left ventricular ratio on baseline CT was 1.7 ± 0.6. After MT, a statistically significant reduction in mean pulmonary artery pressures from 35.9 ± 9.6 to 26.1 ± 9.0 mmHg (p = 0.002) and heart rates from 109.4 ± 22.5 to 82.8 ± 13.8 beats per minute (p < 0.001) was achieved. Two patients died of prolonged cardiogenic shock. Three patients died of post-interventional complications of which a paradoxical embolism can be considered related to MT. One patient needed short cardiopulmonary resuscitation during the procedure due to clot displacement. Patients with PE as primary driver of clinical instability had a median intensive care unit (ICU) stay of 2 days (0.5-3.5 days). Patients who developed PE as a complication of an underlying medical condition spent 11 days (9.5-12.5 days) in the ICU. CONCLUSION: In this small study population of predominantly high-risk PE patients, large-bore MT without adjunctive thrombolysis was feasible with an acceptable procedure-related complication rate.

MR-Guided Percutaneous Intradiscal Thermotherapy (MRgPIT): Evaluation of a New Technique for the Treatment of Degenerative Disc Disease in Cadaveric Lumbar Spine.

PURPOSE: Evaluation of MR feasibility and real-time control of an innovative thermoablative applicator for intradiscal thermotherapy and histological analysis of laser annuloplasty in human ex vivo intervertebral discs. MATERIALS AND METHODS: We evaluated a new MR-compatible applicator system for MR-guided percutaneous intradiscal thermotherapy (MRgPIT) in an open 1.0-T MRI-system. Needle artefacts and contrast-to-noise ratios (CNR) of six interactive sequences (PD-, T1-, T2w TSE, T1-, T2w GRE, bSSFP) with varying echo-times (TE) and needle orientations to the main magnetic field (B0) were analysed. Additionally, five laser protocols (Nd: YAG Laser, 2-6 W) were assessed in 50 ex vivo human intervertebral discs with subsequent histological evaluation. RESULTS: In vitro, we found optimal needle artefacts of 1.5-5 mm for the PDw TSE sequence in all angles of the applicator system to B0. A TE of 20 ms yielded the best CNR. Ex vivo, ablating with 5 W induced histological denaturation of collagen at the dorsal annulus, correlating with a rise in temperature to at least 60 °C. The MRgPIT procedure was feasible with an average intervention time of 17.1 ± 5.7 min. CONCLUSION: Real-time MR-guided positioning of the MRgPIT-applicator in cadaveric intervertebral disc is feasible and precise using fast TSE sequence designs. Laser-induced denaturation of collagen in the dorsal annulus fibrosus proved to be accurate.

[Teleradiological report turnaround times: An internal efficiency and quality control analysis]. / Teleradiologische Prozess- und Untersuchungszeiten: Eine institutsinterne Effizienz- und Qualitätsanalyse.

AIMS: The teleradiological examinations performed at the Charité were analyzed for the purpose of internal quality and efficiency control. Data included the type and number of examinations performed, the time of day and week the examination was performed and the differences in teleradiologist report turnaround times. MATERIAL AND METHODS: A retrospective analysis of the radiology information system (RIS) database of all teleradiological computed tomography examinations performed at the Charité from 2011 through 2013 was carried out. The search retrieved 10,200 teleradiological examinations which were included in the analysis. The records were analyzed for the time of the day and week the examination was performed, the interval between examination and time of reporting, the type of teleradiological examination and the campus in which they were performed. RESULTS: The number of teleradiological examinations performed increased continuously during the observation period. Computed tomography of the head was the most frequently performed type of examination with 86%. Taking all forms of examination into consideration it took an average of 34 min until a report was written. Over the 3-year observation period the times remained virtually unaltered. CONCLUSION: During the 3-year observation period nearly constant report times could be observed in spite of the increased numbers of examinations. This indicates an efficiency enhancement and rational integration of teleradiology into the radiological workflow.

MRI-guided and CT-guided cervical nerve root infiltration therapy: a cost comparison.

PURPOSE: To evaluate and compare the costs of MRI-guided and CT-guided cervical nerve root infiltration for the minimally invasive treatment of radicular neck pain. MATERIALS AND METHODS: Between September 2009 and April 2012, 22 patients (9 men, 13 women; mean age: 48.2 years) underwent MRI-guided (1.0 Tesla, Panorama HFO, Philips) single-site periradicular cervical nerve root infiltration with 40 mg triamcinolone acetonide. A further 64 patients (34 men, 30 women; mean age: 50.3 years) were treated under CT fluoroscopic guidance (Somatom Definition 64, Siemens). The mean overall costs were calculated as the sum of the prorated costs of equipment use (purchase, depreciation, maintenance, and energy costs), personnel costs and expenditure for disposables that were identified for MRI- and CT-guided procedures. Additionally, the cost of ultrasound guidance was calculated. RESULTS: The mean intervention time was 24.9 min. (range: 12 - 36 min.) for MRI-guided infiltration and 19.7 min. (range: 5 - 54 min.) for CT-guided infiltration. The average total costs per patient were EUR 240 for MRI-guided interventions and EUR 124 for CT-guided interventions. These were (MRI/CT guidance) EUR 150/60 for equipment use, EUR 46/40 for personnel, and EUR 44/25 for disposables. The mean overall cost of ultrasound guidance was EUR 76. CONCLUSION: Cervical nerve root infiltration using MRI guidance is still about twice as expensive as infiltration using CT guidance. However, since it does not involve radiation exposure for patients and personnel, MRI-guided nerve root infiltration may become a promising alternative to the CT-guided procedure, especially since a further price decrease is expected for MRI devices and MR-compatible disposables. In contrast, ultrasound remains the less expensive method for nerve root infiltration guidance.

[Turnaround time for reporting results of radiological examinations in intensive care unit patients: an internal quality control]. / Radiologische "report turnaround times" und Untersuchungszeitpunkte bei Patienten auf Intensivstationen : Eine institutsinterne Qualitätskontrolle.

AIMS: The radiological examinations performed in intensive care units (ICUs) were analyzed for the purpose of internal quality control. Data included the type of examination performed, the time of day the examination was performed and the differences in radiologist report turnaround times. MATERIAL AND METHODS: A retrospective analysis of the radiology information system (RIS) database of all radiological examinations performed in the ICU of a large German hospital from 2009 through 2011 was carried out. The search retrieved 75,169 examinations performed in ICU patients which were included in the analysis. The records were analyzed for type of radiological examination performed, i.e. conventional X-ray, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), angiography and nuclear medicine examinations, time of day the examination was performed and the interval between examination and time of reporting and release of the final report. RESULTS: Cross-modality it took on average 52 min until a report was written and approximately 7 h before the final report was released. Turnaround times were shortest for ultrasound, conventional X-ray and CT. Over the 3-year observation period there was an overall tendency toward shorter turnaround times whereby improvement in time until reporting was most marked for conventional X-ray, MRI and ultrasound (reduction of 24, 17, and 15 min, respectively). The time until release of the final report improved most markedly for CT, conventional X-ray and angiography (improvement of approximately 6.67, 5.08 and 0.78 h, respectively). CONCLUSIONS: During the 3-year observation period a reduction in turnaround times for reporting results and release of finalized reports could be observed, despite an increase in the total number of cases.

Cost comparison of nerve root infiltration of the lumbar spine under MRI and CT guidance.

OBJECTIVES: To compare the costs of CT- and MR-guided lumbosacral nerve root infiltration for minimally invasive treatment of low back pain and radicular pain. METHODS: Ninety patients (54 men, 36 women; mean age, 45.5 ± 12.8 years) underwent MR-guided single-site periradicular lumbosacral nerve root infiltration with 40 mg of triamcinolone acetonide. A further 91 patients (48 men, 43 women; mean age, 59.1 ± 13.8 years) were treated under CT fluoroscopy guidance. Prorated costs of equipment use (purchase, depreciation and maintenance), staff costs based on involvement times and expenditure for disposables were identified for MR- and CT-guided procedures. RESULTS: Mean intervention time was 20.6 min (14-30 min) for MR-guided and 14.3 min (7-32 min) for CT-guided treatment. The average total costs per patient were €177 for MR-guided and €88 for CT-guided interventions. These consisted of (MR/CT guidance) €93/29 for equipment use, €43/35 for staff and €41/24 for disposables. CONCLUSIONS: Lumbosacral nerve root infiltration using MRI guidance is still about twice as expensive as infiltration using CT guidance. Given the advantages of no radiation exposure and possible future decrease in prices for MRI devices and MR-compatible injection needles, MR-guided nerve root infiltration may become a promising alternative to the CT-guided procedure. KEY POINTS: • MR-guided nerve root infiltration therapy is now technically and clinically established. • Costs using MRI guidance are still about double those for CT guidance. • MR guidance involves no radiation exposure to patients and personnel. • MR-guided nerve root infiltration may become a promising alternative to CT.

MR-guided periarterial ethanol injection for renal sympathetic denervation: a feasibility study in pigs.

PURPOSE: To evaluate the feasibility and efficacy of image-guided periarterial ethanol injection as an alternative to transluminal radiofrequency ablation. METHODS: Unilateral renal periarterial ethanol injection was performed under general anesthesia in 6 pigs with the contralateral kidney serving as control. All interventions were performed in an open 1.0 T MRI system under real-time multiplanar guidance. The injected volume was 5 ml (95 % ethanol labelled marked MR contrast medium) in 2 pigs and 10 ml in 4 pigs. Four weeks after treatment, the pigs underwent MRI including MRA and were killed. Norepinephrine (NE) concentration in the renal parenchyma served as a surrogate parameter to analyze the efficacy of sympathetic denervation. In addition, the renal artery and sympathetic nerves were examined histologically to identify evidence of vascular and neural injury. RESULTS: In pigs treated with 10 ml ethanol, treatment resulted in neural degeneration. We found a significant reduction of NE concentration in the kidney parenchyma of 53 % (p < 0.02) compared with the untreated contralateral kidney. In pigs treated with 5 ml ethanol, no significant changes in histology or NE were observed. There was no evidence of renal arterial stenosis in MRI, macroscopy or histology in any pig. CONCLUSION: MR-guided periarterial ethanol injection was feasible and efficient for renal sympathetic denervation in a swine model. This technique may be a promising alternative to the catheter-based approach in the treatment of resistant arterial hypertension.

Treatment of osteoid osteoma using CT-guided radiofrequency ablation versus MR-guided laser ablation: a cost comparison.

OBJECTIVE: To compare the costs of CT-guided radiofrequency ablation (RFA) and MR-guided laser ablation (LA) for minimally invasive percutaneous treatment of osteoid osteoma. MATERIALS AND METHODS: Between November 2005 and October 2011, 20 patients (14 males, 6 females, mean age 20.3±9.1 years) underwent CT-guided RFA and 24 patients (18 males, 6 females; mean age, 23.8±13.8 years) MR-guided LA (open 1.0 Tesla, Panorama HFO, Philips, Best, Netherlands) for osteoid osteoma diagnosed on the basis of clinical presentation and imaging findings. Prorated costs of equipment use (purchase, depreciation, and maintenance), staff costs, and expenditure for disposables were identified for CT-guided RFA and MR-guided LA procedures. RESULTS: The average total costs per patient were EUR 1762 for CT-guided RFA and EUR 1417 for MR-guided LA. These were (RFA/LA) EUR 92/260 for equipment use, EUR 149/208 for staff, and EUR 870/300 for disposables. CONCLUSION: MR-guided LA is less expensive than CT-guided RFA for minimally invasive percutaneous ablation of osteoid osteoma. The higher costs of RFA are primarily due to the higher price of the disposable RFA probes.

Magnetic resonance imaging of the active second stage of labour: proof of principle.

OBJECTIVE: To prove that magnetic resonance imaging of foetal anatomy during the active second stage of vaginal delivery is feasible. MATERIALS AND METHODS: Initially, five pregnant volunteers around the 30th week of gestation were examined in an open MRI. Based on the findings, one vaginal delivery was acquired under real-time imaging. To monitor the birth status during image acquisition, an MR-compatible wireless cardiotocography (CTG) system was built. Single-shot sequence parameters were optimised to compensate motion artefacts during labour. RESULTS: Safety requirements to monitor the birth process under real-time MR imaging were met. High-resolution MR images were acquired immediately before and after delivery. In one patient, TSE single-shot cinematic sequences of the active second stage of labour were obtained. All sequences were adapted to tolerate movement of the mother and infant, as well as residual noise from the CTG. Furthermore, the MR imaging during labour showed only minor image artefacts. CONCLUSION: CTG-monitored acquisition of MRI series during the active second stage of delivery is feasible. Image quality should allow various further studies to improve models for birth simulation as well as potential investigation of obstructed labour and obstetric complications.

Ischemic-type biliary lesions after ortothopic liver transplantation: diagnosis with magnetic resonance cholangiography.

PURPOSE: To determine the accuracy of magnetic resonance (MR) cholangiography for detection of ischemic-type biliary lesions (ITBL) following orthotropic liver transplantation (OLT). MATERIALS AND METHODS: MR cholangiography was performed in 16 patients with established diagnosis of ITBL following OLT. Two blinded observers reviewed all images in consensus and recorded diagnostic features including presence of intrahepatic and extrahepatic biliary strictures, dilatations, beading, pruning, and filling defects. Sensitivity, specificity, positive predictive value, and accuracy of MR cholangiography were calculated. Final diagnosis was established at endoscopic retrograde cholangiography. RESULTS: MR cholangiography proved to be a valuable tool for the detection of stenoses and dilatations in patients with ITBL following OLT. Sensitivity of the different diagnostic features ranged between 71% and 100%, specificity between 50% and 100%, accuracy between 81% and 100%, and positive predictive value between 87% and 100%. CONCLUSION: MR cholangiography proved to be an accurate imaging technique to noninvasively detect biliary complications in patients with ITBL after OLT.

CT-guided biopsies: quality, complications and impact on treatment: a retrospective initial quality control.

PURPOSE: To retrospectively evaluate the quality and complications of CT-guided biopsies and their impact on treatment. MATERIALS AND METHODS: A total of 265 CT-guided interventions performed during a 6-month period were extracted by digital database query. These included 127 CT-guided biopsies, which were classified by patient age, organ/body area, histopathological biopsy diagnosis, complications, and performing physician. RESULTS: In 51 % of cases (65 / 127), CT-guided biopsies led to a malignant diagnosis and a change in the patient's treatment. Retrospectively, complications were to be expected in a range of 12 - 26 %, given a 95 % confidence interval. In terms of organ/body area, most complications occurred in lung biopsies (23 / 56; 41 %). 80 % of CT-guided biopsies were performed without complications. 2 of the 11 physicians performed 66 % of all biopsies (84 / 127) and had significantly fewer complications than the others. Patient age was a statistically significant factor for complications (p < 0.018) as well as for a malignant biopsy diagnosis (p < 0.009). CONCLUSION: Our initial quality control assessment suggests that frequent use of CT-guided biopsy by the performing physician rather than the general level of experience is associated with fewer complications for patients. Age is a significant factor for complications of CT-guided biopsies, thus leading to an increased risk/benefit ratio. As expected, age also significantly increases the risk of a malignant biopsy result. Complications and malignant biopsy results were not significantly associated. CT-guided biopsies triggered a change in treatment in over 50 % of cases.

[Magnetic resonance cholangiographic (MRCP) features of ischemic-type biliary lesions (ITBL): a case-control study]. / Magnetresonanz-Cholangiografie (MRCP) bei Patienten mit Ischemic-Type Biliary Lesions (ITBL): eine Fall-Kontroll-Studie.

PURPOSE: To evaluate the spectrum of MR cholangiography (MRCP) features of ischemic-type biliary lesions (ITBL) after orthotopic liver transplantation (OLT). MATERIALS AND METHODS: 30 patients (16 m, 14 f) with an average age of 52 years (9 - 69 y) were examined in two 1.5 MR units using breath-hold 2D-SS-FSE-sequences and 3D-MRCP sequences. 20 of the 30 patients had an established ITBL, and the remaining 10 patients were post-OLT controls. MRCPs were evaluated independently by two experienced radiologists that were blinded to the clinical history as well as the results of other imaging modalities. All images were analyzed for the presence of 16 different pathological features. Differences between ITBL patients and controls were analyzed using the Mann-Whitney-U Test. Inter-rater variability was tested using the Cohen's Kappa test. RESULTS: Abnormal findings of bile ducts were seen in all patients. The most common findings were (in percentage for reader 1 / 2) intrahepatic bile duct dilatation (95 % / 95 %) and extrahepatic bile duct stenoses (95 % / 85 %), followed by intrahepatic main duct stenoses (90 % / 95 %) and segmental duct stenoses (85 % / 85 %). Differences between ITBL patients and controls were significant for most of the analyzed features (Mann-Whitney-U test, p < 0.05). For 12 of 16 features, there was substantial or almost perfect agreement (κ = 0.61 - 1.00), for 2 of 16 features moderate agreement (κ = 0.41- 0.60) and for 2 of 16 features fair agreement (κ < 0.40). CONCLUSION: In patients with ITBL, MR cholangiography reveals characteristic features that may allow differentiation from other biliary complications after liver transplantation.

MR-guided discography using an open 1 Tesla MRI system.

OBJECTIVE: To evaluate the feasibility of MR-guided discography using an open 1 Tesla MRI system. METHODS: 48 disc segments of 41 patients scheduled for intradiscal thermal treatment, total disc replacement or spondylodesis were examined. A 1.0-T open MRI was used for instrument guidance and imaging. After primary disc puncture under guidance of interactive PDw TSE imaging, 1-2 ml of gadolinium contrast saline mixture was injected into the disc. The occurrence of memory pain during injection was recorded. Axial and sagittal T1w TSE images with and without fat saturation were obtained. All MRI discograms were analysed by two readers, who were blinded to the clinical findings. RESULTS: Overall, the placement of the puncture needle in the targeted disc was accurate under real-time MR guidance. Injections were technically successful in all cases. No major complications occurred. The mean procedure time was 17 min (range 13-34 min). Image quality of contrast-enhanced MR discograms was excellent when using an optimized gadolinium contrast saline mixture of 1:600. Memory pain was detected in 16 out of 48 affected segments. CONCLUSION: MR-guided discography is accurate and safe. Multiplanar dynamic imaging facilitates the puncture of discs and provides high-quality MR discograms.

[Quality management systems in radiology: implementation in hospital and radiology practice]. / Qualitätsmanagementsysteme in der Radiologie: Umsetzung in der Klinik und Praxis.

The concept of quality and the principle of continuous quality improvement are implemented by quality management systems. Quality management systems surpass mere quality control. These systems account for patient and employee needs, the management style and the structure of an enterprise. Many of these quality management systems are used in the health care industry. Some of these systems and their form of application in radiology are introduced here.