Analysis of patient's X-ray exposure in hepatic chemosaturation procedures: a single center experience.

BACKGROUND: Hepatic chemosaturation is a technique in which a high dose of the chemotherapeutic agent melphalan is administered directly into the liver while limiting systemic side effects. We reviewed our institutional experience regarding patient's X-ray exposure caused by the procedure. METHODS: Fifty-five procedures, performed between 2016 and 2020 in 18 patients by three interventional radiologists (radiologist), were analyzed regarding the patient's exposure to radiation. Dose-area-product (DAP) and fluoroscopy time (FT) were correlated with the experience of the radiologist and whether the preprocedural evaluation (CS-EVA) and the procedure were performed by the same radiologist. Additionally, the impact of previous liver surgery on DAP/FT was analyzed. RESULTS: Experienced radiologist require less DAP/FT (50 ± 18 Gy*cm2/13.2 ± 3.84 min vs. 69 ± 20 Gy*cm2/15.77 ± 7.82 min; p < 0.001). Chemosaturations performed by the same radiologist who performed CS-EVA required less DAP/FT (41 ± 12 Gy*cm2/11.46 ± 4.41 min vs. 62 ± 11 Gy*cm2/15.55 ± 7.91 min; p < 0.001). Chemosaturations in patients with prior liver surgery with involvement of the inferior cava vein required significantly higher DAP/FT (153 ± 27 Gy*cm2/25.43 ± 4.57 min vs. 56 ± 25 Gy*cm2/14.44 ± 7.55 min; p < 0.001). CONCLUSION: There is a significant learning curve regarding the procedure of hepatic chemosaturation. Due to dose reduction the evaluation and chemosaturation therapy should be performed by the same radiologist. Procedures in patients with previous liver surgery require higher DAP/FT.

Body fat composition determines outcomes before and after liver transplantation in patients with cirrhosis.

Cachexia occurs in late stages of liver cirrhosis, and a low-fat mass is potentially associated with poor outcome. This study compared different computed tomography (CT)-derived fat parameters with respect to its prognostic impact on the development of complications and death before and after liver transplantation. Between 2001 and 2014, 612 patients with liver cirrhosis without hepatocellular carcinoma listed for liver transplantation met the inclusion criteria, including abdominal CT scan (±200 days to listing). A total of 109 patients without cirrhosis served as controls. The subcutaneous fat index (SCFI), the paraspinal muscle fat index, and the visceral fat index were assessed at L3/L4 level and normalized to the height (cm2 /m2 ). Data were collected and analyzed retrospectively. Low SCFI was associated with a higher rate of ascites and increased C-reactive protein levels (p < 0.001). In addition, multivariate Cox regression analysis adjusting for sex, age, body mass index (BMI), and Model for End-Stage Liver Disease showed that decreasing SCFI was also associated with an increased risk of cirrhosis-related complications (p = 0.003) and death on the transplant wait list (p = 0.013). Increased paraspinal and visceral fat were not only positively correlated with creatinine levels (p < 0.001), BMI, and metabolic comorbidities (all p < 0.001) before transplantation, but also predictive for 1-year mortality after transplantation. Conclusion: The distribution of body fat is a major determinant for complications and outcome in cirrhosis before and after liver transplantation.

Repeated percutaneous hepatic perfusion with melphalan can maintain long-term response in patients with liver cancers.

Chemosaturation (CS; CHEMOSAT®, Delcath Systems Inc.) temporarily administers melphalan into the liver by percutaneous hepatic perfusion (PHP). CS-PHP can effectively control growth in liver tumors, but efficacy and tolerability of sequential treatments are unclear. We analyzed outcomes of sequential CS-PHP treatment. Patients with either unresectable intrahepatic metastases of ocular melanoma (OM, n = 9), cholangiocarcinoma (CCA, n = 3), or hepatocellular carcinoma (HCC, n = 1) were recruited retrospectively. Response was assessed by tomography imaging. Ten patients (mean age 60 years) with more than one CS-PHP treatment were included. CS-PHP was administered 2-6 times in the OM patients, 3 times in the CCA, and the HCC patient received 6 treatments. Overall response rate (ORR) to CS-PHP was 80%, and stable disease was achieved in one patient. Median hepatic progression-free survival (hPFS) was 336 days (range 0-354) for OM, 251 days for the CCA patient, and 256 days for the HCC patient. At the end of observation (153-701 days after first CS-PHP), 6/10 patients were still alive (5/9 with OM, 0 with CCA, and 1 with HCC). Death cases were not related to CS-PHP. Adverse events were mostly hematologic, grade I-IV, and self-resolving. The liver function was not deteriorated by CS-PHP. We conclude that repeated CS-PHP treatments were effective and well tolerated in the long term.

Retrospective Study for Validation and Improvement of Numerical Treatment Planning of Irreversible Electroporation Ablation for Treatment of Liver Tumors.

OBJECTIVE: The aims of this study were to determine the electric field threshold that best fits the local response to irreversible electroporation (IRE) ablation of hepatic tumors as seen in follow-up MRI; to numerically evaluate the heat generating effect of IRE; and to demonstrate the utility of treatment planning to improve procedures in the future. METHODS: 18 cases of hepatic tumors treated with IRE ablation were numerically reconstructed and treatment outcome was computed with a numerical treatment planning framework. Simulated ablation volumes were compared to ablation volumes segmented from 6-week follow-up MRI. Two cases with a high thermal component were selected for numerical optimization. RESULTS: The best fit between segmented and simulated ablation zones was obtained at 900 V/cm threshold with the average absolute error of 5.6 ± 1.5 mm. Considerable heating was observed in 7/18 cases, where >50% of tumor volume experienced heating likely to cause thermal damage. In the selected two cases, thermal damage was eliminated with adjustment of applied voltages. CONCLUSION: Lesions visible on MRI 6 weeks post IRE represent areas that experienced an electric field of 900 V/cm or higher. This threshold is higher than previously reported for IRE of hepatic tumors. It is likely the 6-week follow-up period was too long and the ablation zone has already shrunk considerably, resulting in overestimation of the threshold. SIGNIFICANCE: We developed a sophisticated method for validation of the numerical treatment planning framework. A future prospective study can be effectively designed based on the findings of this study.

Validation of a Web-Based Planning Tool for Percutaneous Cryoablation of Renal Tumors.

PURPOSE: To validate a simulation environment for virtual planning of percutaneous cryoablation of renal tumors. MATERIALS AND METHODS: Prospectively collected data from 19 MR-guided procedures were used for validation of the simulation model. Volumetric overlap of the simulated ablation zone volume (Σ) and the segmented ablation zone volume (S; assessed on 1-month follow-up scan) was quantified. Validation metrics were DICE Similarity Coefficient (DSC; the ratio between twice the overlapping volume of both ablation zones divided by the sum of both ablation zone volumes), target overlap (the ratio between the overlapping volume of both ablation zones to the volume of S; low ratio means S is underestimated), and positive predictive value (the ratio between the overlapping volume of both ablation zones to the volume of Σ; low ratio means S is overestimated). Values were between 0 (no alignment) and 1 (perfect alignment), a value > 0.7 is considered good. RESULTS: Mean volumes of S and Σ were 14.8 cm3 (± 9.9) and 26.7 cm3 (± 15.0), respectively. Mean DSC value was 0.63 (± 0.2), and ≥ 0.7 in 9 cases (47%). Mean target overlap and positive predictive value were 0.88 (± 0.11) and 0.53 (± 0.24), respectively. In 17 cases (89%), target overlap was ≥ 0.7; positive predictive value was ≥ 0.7 in 4 cases (21%) and < 0.6 in 13 cases (68%). This indicates S is overestimated in the majority of cases. CONCLUSION: The validation results showed a tendency of the simulation model to overestimate the ablation effect. Model adjustments are necessary to make it suitable for clinical use.

Position Paper of the German Society for Interventional Radiology (DeGIR) on Prostatic Artery Embolization. / Positionspapier der Deutschen Gesellschaft für Interventionsradiologie (DeGIR) zur Prostataarterienembolisation.

BACKGROUND: In recent years prostate artery embolization (PAE) evolved into a clinically established minimally invasive endovascular treatment option for lower urinary tract symptoms caused by benign prostate syndrome (BPS). METHODS: In this interdisciplinary position paper, initiated by the steering group for research of the German Society for Interventional Radiology (IR), the method of PAE is presented and discussed in the context of current evidence. RESULTS: PAE is a safe IR procedure for the treatment of BPS. In terms of symptom relief, measured with the IPSS (International Prostate Symptom Score), the PAE has comparable effect, similar to the historic gold standard, transurethral resection (TUR) of the prostate. With regard to reducing subvesical obstruction PAE is inferior to TUR, but does not limit subsequent surgery. Based on current evidence, PAE is recommended by the British National Institute for Health and Care Excellence as an alternative therapy. The feasibility under local anaesthesia and the preservation of sexual function are important arguments for patients in favour of interventional therapy. Patient selection and therapy concepts require close interdisciplinary collaboration between urologists and radiologists. CONCLUSION: Effectiveness and safety of PAE for the treatment of BPS are proven. Further randomized trials should focus on long term outcome and help to identify most suitable indications for PAE. KEY POINTS: · PAE, an endovascular procedure, is a patient-friendly, minimally invasive, alternative therapy option of the BPS. · PAE can reduce the symptoms of the lower urinary tract (LUTS), comparable to transurethral resection (TUR). The deobstructive and volume-reducing potential of the PAE is inferior to that of the TUR. · The main advantages of PAE are use of local anesthesia (no general anesthesia required), short patient recovery and maintenance of sexual function, including antegrade ejaculation.. · Based on current evidence PAE should be considered after conservative drug therapy and before TUR.. · The role of PAE in the context of other minimally invasive procedures (MIST) requires further evaluation with an open minded approach towards PAE.. · PAE is carried out by interventional radiologists, usually on a referral basis from urologists, and requires close interdisciplinary cooperation.. CITATION FORMAT: · Kovacs A, Bücker A, Grimm M et al. Position Paper of the German Society for Interventional Radiology (DeGIR) on Prostatic Artery Embolization. Fortschr Röntgenstr 2020; 192: 835 - 846.

Definitions of Computer-Assisted Surgery and Intervention, Image-Guided Surgery and Intervention, Hybrid Operating Room, and Guidance Systems: Strasbourg International Consensus Study.

OBJECTIVE: To develop consensus definitions of image-guided surgery, computer-assisted surgery, hybrid operating room, and surgical navigation systems. SUMMARY BACKGROUND DATA: The use of minimally invasive procedures has increased tremendously over the past 2 decades, but terminology related to image-guided minimally invasive procedures has not been standardized, which is a barrier to clear communication. METHODS: Experts in image-guided techniques and specialized engineers were invited to engage in a systematic process to develop consensus definitions of the key terms listed above. The process was designed following review of common consensus-development methodologies and included participation in 4 online surveys and a post-surveys face-to-face panel meeting held in Strasbourg, France. RESULTS: The experts settled on the terms computer-assisted surgery and intervention, image-guided surgery and intervention, hybrid operating room, and guidance systems and agreed-upon definitions of these terms, with rates of consensus of more than 80% for each term. The methodology used proved to be a compelling strategy to overcome the current difficulties related to data growth rates and technological convergence in this field. CONCLUSIONS: Our multidisciplinary collaborative approach resulted in consensus definitions that may improve communication, knowledge transfer, collaboration, and research in the rapidly changing field of image-guided minimally invasive techniques.

Clinical evaluation of in silico planning and real-time simulation of hepatic radiofrequency ablation (ClinicIMPPACT Trial).

OBJECTIVES: To evaluate the accuracy and clinical integrability of a comprehensive simulation tool to plan and predict radiofrequency ablation (RFA) zones in liver tumors. METHODS: Forty-five patients with 51 malignant hepatic lesions of different origins were included in a prospective multicenter trial. Prior to CT-guided RFA, all patients underwent multiphase CT which included acquisitions for the assessment of liver perfusion. These data were used to generate a 3D model of the liver. The intra-procedural position of the RFA probe was determined by CT and semi-automatically registered to the 3D model. Size and shape of the simulated ablation zones were compared with those of the thermal ablation zones segmented in contrast-enhanced CT images 1 month after RFA; procedure time was compared with a historical control group. RESULTS: Simulated and segmented ablation zone volumes showed a significant correlation (ρ = 0.59, p < 0.0001) and no significant bias (Wilcoxon's Z = 0.68, p = 0.25). Representative measures of ablation zone comparison were as follows: average surface deviation (absolute average error, AAE) with 3.4 ± 1.7 mm, Dice similarity coefficient 0.62 ± 0.14, sensitivity 0.70 ± 0.21, and positive predictive value 0.66 ± 0. There was a moderate positive correlation between AAE and duration of the ablation (∆t; r = 0.37, p = 0.008). After adjustments for inter-individual differences in ∆t, liver perfusion, and prior transarterial chemoembolization procedures, ∆t was an independent predictor of AAE (ß = 0.03 mm/min, p = 0.01). Compared with a historical control group, the simulation added 3.5 ± 1.9 min to the procedure. CONCLUSION: The validated simulation tool showed acceptable speed and accuracy in predicting the size and shape of hepatic RFA ablation zones. Further randomized controlled trials are needed to evaluate to what extent this tool might improve patient outcomes. KEY POINTS: • More reliable, patient-specific intra-procedural estimation of the induced RFA ablation zones in the liver may lead to better planning of the safety margins around tumors. • Dedicated real-time simulation software to predict RFA-induced ablation zones in patients with liver malignancies has shown acceptable agreement with the follow-up results in a first prospective multicenter trial suggesting a randomized controlled clinical trial to evaluate potential outcome benefit for patients.

Segmental intrahepatic cholestasis as a technical complication of the transjugular intrahepatic porto-systemic shunt.

BACKGROUND: Segmental intrahepatic cholestasis caused by transjugular intrahepatic portosystemic shunt (TIPS) (SIC-T), is a rare complication of this technique and only referred by case reports. Thus, we conducted a systematic, retrospective analysis to provide evidence regarding prevalence and consequences of this TIPS-induced bile duct compression. AIM: To assess prevalence and outcome of SIC-T in a large TIPS-cohort. METHODS: In this retrospective cohort study, we screened the institutional databases for all consecutive patients that were treated by TIPS-placement or TIPS-revision between January 2005 and August 2013. We analyzed radiologic images for signs of biliary congestion. Cases that were indicative of SIC-T were reviewed by two independent radiologists and additional patient data was collected. Descriptive statistics of patient demographics, indications for TIPS and procedural details were registered. Logistic regression analysis was performed to identify predictors for the development of SIC-T. RESULTS: We analyzed 135 cirrhotic patients who underwent TIPS (mean age 55 years, 79% male gender). Etiology of cirrhosis was alcohol in most cases and indications for TIPS were mainly refractory ascites and recurrent variceal bleeding. TIPS revision was necessary in 31 patients. We identified 4 cases (2.9%) of SIC-T in direct proximity of the TIPS-stent. Diagnosis was confirmed by CT-scan, MRI or endoscopic retrograde cholangio pancreaticography (ERCP). In two patients TIPS was implanted via the right and in one through the medial hepatic vein. One patient received TIPS-prolongation by multiple revisions. Most patients were asymptomatic but one cholangitic abscess necessitated a transhepatic drain. Logistic regression analysis identified TIPS-placement other than from medial hepatic vein to right portal vein as risk factor (OR 21.0) for SIC-T. CONCLUSION: SIC-T ads to (mostly late) complications in the interventional treatment of cirrhotic portal hypertensions and can lead to cholangitic abscesses. Patients, particularly with multiple interventions, should be screened for SIC-T.

In-bore biopsies of the prostate assisted by a remote-controlled manipulator at 1.5 T.

PURPOSE: To evaluate the technical and clinical utility of a fully MRI-compatible, pneumatically driven remote-controlled manipulator (RCM) for targeted biopsies of the prostate at 1.5 T. MATERIALS AND METHODS: The data of the first 22 patients that were biopsied under robotic assistance were analyzed. Interventional planning relied on T2-weighted (T2w) turbo spin-echo (TSE) images (axial and sagittal) with a high-b-value diffusion-weighted acquisition added in selected cases. Alignment of the needle guide was controlled with a short balanced SSFP sequence in two oblique planes along the MR-visible sheath. Signals were acquired with a combination of elements from a 30-channel body and a 32-channel spine coil. Biopsy samples were taken with a fully automatic 18-G biopsy gun with a length of 150 or 175 mm. RESULTS: Mean age was 66.6 years and average PSA level was 11.5 ng/ml. Fourteen out of 22 patients (63%) had received prior biopsies under transrectal ultrasound guidance. Diagnostic MRI reports (before biopsy) involved 17 cases with a single suspicious finding (four PI-RADS 3, one PI-RADS 3-4, eight PI-RADS 4 and nine PI-RADS 5 cases). The median effective procedure time was 33.9 (range 25.0-55.9) min for 16 cases with one CSR and 63.4 (52.7-81.8) min for 5 cases with two CSRs. The biopsy with three CSRs took 74.0 min. Histopathologic examination revealed prostate cancer in 14 of 22 cases. CONCLUSION: MR-targeted, transrectal biopsy of the prostate could be reliably performed with a robotic manipulator at a field strength of 1.5 T. Balanced SSFP imaging is considered a viable option for fast procedural control. Follow-up work needs to evaluate to what extent in-bore adjustments and workflow enhancements will contribute to shorter procedure times or higher patient comfort.

Hilar en bloc resection for hilar cholangiocarcinoma in patients with limited liver capacities-preserving parts of liver segment 4.

BACKGROUND: A right trisectionectomy with portal vein resection represents the conventional approach for hilar cholangiocarcinoma. Here, we present a technical modification of hilar en bloc resection in order to increase the remnant volume by partially preserving liver segment 4. METHODS: The caudal parenchymal dissection line starts centrally between the left lateral and left medial segments. Cranially, the resection line switches to the right towards Cantlie's line and turns again upwards perpendicularly. Hence, segment 4a and subtotal segment 4b are partially preserved by this novel technique. The left hepatic duct is dissected at the segmental ramification and reconstruction is performed as a single hepaticojejunostomy. The feasibility of the novel parenchyma-sparing approach for hilar cholangiocarcinoma was proven in a case series and medical records were reviewed retrospectively. RESULTS: Ten patients (6 male, 4 female) underwent segment 4 partially preserving right trisectionectomy for hilar cholangiocarcinoma. Estimated future liver remnant volume was significantly increased (FLRV 38.3%), when compared to standard right trisectionectomy (FLRV 23.9%; p < 0.01). Three of 10 liver resections were associated with major surgical complications (≥IIIb; n = 3); categorized according to the Dindo-Clavien classification. No patient died due to complications associated with postoperatively impaired liver function. Tumor-free margins could be achieved in 8 patients while median overall survival and disease-free survival were 547 and 367 days, respectively. CONCLUSION: This novel parenchyma-sparing modification of hilar en bloc resection by partially preserving segment 4 allows to safely increase the remnant liver volume without neglecting principles of local radicality.

Loss of paraspinal muscle mass is a gender-specific consequence of cirrhosis that predicts complications and death.

BACKGROUND: Loss of skeletal muscle mass is a recognised complication with a prognostic impact in patients with cirrhosis. AIM: To explore in a retrospective analysis which muscle compartment most reliably predicts the occurrence of cirrhosis-associated complications and if there are gender-related differences. METHODS: 795 patients with cirrhosis listed for liver transplantation between 2001 and 2014 met the inclusion and exclusion criteria including an abdominal CT scan (±200). Controls were 109 patients who underwent a CT scan after polytrauma. The paraspinal muscles index (PSMI), the abdominal wall muscles index (AWMI) and its combination skeletal muscle index (SMI) were assessed at L3/L4, normalised to the height (cm2 /m2 ). RESULTS: 62.0% of patients with cirrhosis had alcoholic liver disease, and 70.6% were male. As compared to controls, a reduction in PSMI and SMI but not AWMI was associated with high model of end-stage liver disease (MELD) score, high Child-Pugh class, and the presence or history of cirrhosis-associated complications in males but not females. PSMI independently predicted the occurrence of bacterial infections (HR 0.932), spontaneous bacterial peritonitis (HR 0.901), hepatic encephalopathy (HR 0.961), and hepatorenal syndrome (HR 0.946) by multivariate Cox regression analysis in a gender-independent manner. Post-transplant survival was not associated with the PSMI; neither AWMI nor SMI predicted any clinical endpoints. CONCLUSIONS: This study links muscle wasting in patients with cirrhosis predominantly to males. However, the presence of a low PSMI mass is a gender-independent predictor of developing cirrhosis-associated complications and death. Scores combining the MELD with muscle parameters should be re-validated by utilizing the PSMI.

Ischaemic preconditioning of the spinal cord to prevent spinal cord ischaemia during endovascular repair of thoracoabdominal aortic aneurysm: first clinical experience.

AIMS: The purpose of our study was to report our experience with minimally invasive segmental artery coil embolisation (MISACE) to prevent spinal cord ischaemia (SCI) after endovascular repair (ER) of thoracoabdominal aortic aneurysm (TAAA). METHODS AND RESULTS: A cohort of 57 patients with TAAAs was treated by MISACE followed by ER between October 2014 and December 2017. The TAAA Crawford classification was: type I, n=5; type II, n=12; type III, n=27; type IV, n=13. The average maximum aortic diameter was 62.7±8.8 mm. Patients had a median of 5 coiled SAs (range: 1-19). MISACE was completed in one (n=22), two (n=24), three (n=7), four (n=3) or five (n=1) sessions. The maximum number of coiled SAs per session was six. After completion of MISACE, 77.7% of direct segmental arterial flow was occluded. After a mean of 83±62 days, 55 of the patients received total ER of their TAAA. At 30 days after ER, no patient developed SCI and three patients had died. CONCLUSIONS: MISACE to precondition the paraspinous collateral network prior to endovascular repair of thoracoabdominal aortic aneurysm is clinically feasible. The safety profile is promising and there is good reason to explore this new staging strategy further.

Techniques for Interventional MRI Guidance in Closed-Bore Systems.

Efficient image guidance is the basis for minimally invasive interventions. In comparison with X-ray, computed tomography (CT), or ultrasound imaging, magnetic resonance imaging (MRI) provides the best soft tissue contrast without ionizing radiation and is therefore predestined for procedural control. But MRI is also characterized by spatial constraints, electromagnetic interactions, long imaging times, and resulting workflow issues. Although many technical requirements have been met over the years-most notably magnetic resonance (MR) compatibility of tools, interventional pulse sequences, and powerful processing hardware and software-there is still a large variety of stand-alone devices and systems for specific procedures only.Stereotactic guidance with the table outside the magnet is common and relies on proper registration of the guiding grids or manipulators to the MR images. Instrument tracking, often by optical sensing, can be added to provide the physicians with proper eye-hand coordination during their navigated approach. Only in very short wide-bore systems, needles can be advanced at the extended arm under near real-time imaging. In standard magnets, control and workflow may be improved by remote operation using robotic or manual driving elements.This work highlights a number of devices and techniques for different interventional settings with a focus on percutaneous, interstitial procedures in different organ regions. The goal is to identify technical and procedural elements that might be relevant for interventional guidance in a broader context, independent of the clinical application given here. Key challenges remain the seamless integration into the interventional workflow, safe clinical translation, and proper cost effectiveness.

RFA Guardian: Comprehensive Simulation of Radiofrequency Ablation Treatment of Liver Tumors.

The RFA Guardian is a comprehensive application for high-performance patient-specific simulation of radiofrequency ablation of liver tumors. We address a wide range of usage scenarios. These include pre-interventional planning, sampling of the parameter space for uncertainty estimation, treatment evaluation and, in the worst case, failure analysis. The RFA Guardian is the first of its kind that exhibits sufficient performance for simulating treatment outcomes during the intervention. We achieve this by combining a large number of high-performance image processing, biomechanical simulation and visualization techniques into a generalized technical workflow. Further, we wrap the feature set into a single, integrated application, which exploits all available resources of standard consumer hardware, including massively parallel computing on graphics processing units. This allows us to predict or reproduce treatment outcomes on a single personal computer with high computational performance and high accuracy. The resulting low demand for infrastructure enables easy and cost-efficient integration into the clinical routine. We present a number of evaluation cases from the clinical practice where users performed the whole technical workflow from patient-specific modeling to final validation and highlight the opportunities arising from our fast, accurate prediction techniques.

Correction to: Hilar en bloc resection for hilar cholangiocarcinoma in patients with limited liver capacities-preserving parts of liver segment 4.

[This corrects the article DOI: 10.1007/s10353-017-0507-8.].

Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies.

Purpose Analysis of patient´s X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Materials and Methods Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, and fluoroscopy time (FT) were correlated with the used x-ray systems (Flatpanel Detector (FD) vs. Image Itensifier (BV)) and the necessity for periprocedural placement of a nasogastric tube. Additionally, the effective X-ray dose for PRG placement using fluoroscopy (DL), computed tomography (CT), and cone beam CT (CBCT) was estimated using a conversion factor. Results The median DFP of PRG-placements under fluoroscopy was 163 cGy*cm2 (flat panel detector systems: 155 cGy*cm2; X-ray image intensifier: 175 cGy*cm2). The median DLZ was 2.2 min. Intraprocedural placement of a naso- or orogastric probe (n = 68) resulted in a significant prolongation of the median DLZ to 2.5 min versus 2 min in patients with an already existing probe. In addition, dose values were analyzed in smaller samples of patients in which the PRG was placed under CBCT (n = 7, median DFP = 2635 cGy*cm2), or using CT (n = 4, median DLP = 657 mGy*cm). Estimates of the median DFP and DLP showed effective doses of 0.3 mSv for DL-assisted placements (flat panel detector 0.3 mSv, X-ray image converter 0.4 mSv), 7.9 mSv using a CBCT - flat detector, and 9.9 mSv using CT. This corresponds to a factor 26 of DL versus CBCT, or a factor 33 of DL versus CT. Conclusion In order to minimize X-ray exposure during PRG-procedures for patients and staff, fluoroscopically-guided interventions should employ flat detector systems with short transmittance sequences in low dose mode and with slow image frequency. Series recordings can be dispensed with. The intraprocedural placement of a naso- or orogastric probe significantly extends FT, but has little effect on the overall dose of the intervention. Due to the significantly higher X-ray exposure, the use of a CBCT as well as PRG-placements using CT should be limited to clinically absolutely necessary exceptions with strict indication. Key Points · Fluoroscopically-guided PRG placements are interventions with low X-ray exposure.. · X-ray exposure from fluoroscopy is lower using flat panel detector systems as compared to image intensifier systems.. · The concomitant placement of an oro- or nasogastric probe extends the fluoroscopy time.. · Gastric probe placement is worthwhile to prevent the premature use of the significantly radiation-intensive CT.. · The use of the C-arm CT or the CT increases the beam exposure by 26 or 33 times, respectively.. · The PRG placement using C-arm CT and CT should only be performed in exceptional cases.. Citation Format · Petersen TO, Reinhardt M, Fuchs J et al. Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies. Fortschr Röntgenstr 2017; 189: 820 - 827.

Impact of the use of an endorectal coil for 3 T prostate MRI on image quality and cancer detection rate.

This work aims to assess the impact of an additional endorectal coil on image quality and cancer detection rate within the same patients. At a single academic medical center, this transversal study included 41 men who underwent T2- and diffusion-weighted imaging at 3 T using surface coils only or in combination with an endorectal coil in the same session. Two blinded readers (A and B) randomly evaluated all image data in separate sessions. Image quality with respect to localization and staging was rated on a five-point scale. Lesions were classified according to their prostate imaging reporting and data system (PIRADS) score version 1. Standard of reference was provided by whole-mount step-section analysis. Mean image quality scores averaged over all localization-related items were significantly higher with additional endorectal coil for both readers (p < 0.001), corresponding staging-related items were only higher for reader B (p < 0.001). With an endorectal coil, the rate of correctly detecting cancer per patient was significantly higher for reader B (p < 0.001) but not for reader A (p = 0.219). The numbers of histologically confirmed tumor lesions were rather similar for both settings. The subjectively rated 3-T image quality was improved with an endorectal coil. In terms of diagnostic performance, the use of an additional endorectal coil was not superior.