Os calcaneus secundarius, a relevant differential diagnosis to fracture or pseudarthrosis of processus anterior of the calcaneus: a CT morphologic description.

PURPOSE: A fracture or a pseudarthrosis of the processus anterior calcanei (PAC) as well as a traumatized Os calcaneus secundarius (OCS) is often overlooked. A clinical or conventional radiological differentiation of these is uncertain. Therefore, a CT scan is recommended. The aim of the study was to identify CT morphological differentiators between OCS and pathologies of PAC. METHODS: All CT scans at our trauma center level I from 2010 to 2014, which imaged the entire foot, performed after acute trauma or postoperative control were retrospectively re-examined for OCS, other accessory ossicles (oAOS), fracture or pseudarthrosis of PAC and analyzed for specifiers. RESULTS: In 611 CT examinations, 14 (2.3%) accessory ossicles (AOS) at the PAC were detected. 12 (86%) were identified as typical OCS and 2 (14%) as oAOS. 56 (9.2%) pathologies were detected. Of these, 44 (79%) were declared as fractures and 12 (21%) as pseudarthrosis. 7 OCS (58%) and 25 (46%) of the pathologies were not mentioned in the initial CT reports. The main differentiators of OCS to fracture of PAC were the anteromedial localization into a concave notch at the calcaneal facet at PAC and the continuous corticalization. With increasing size, radiological osteoarthritic signs at the OCS were frequent (p ≤ 0.05). CONCLUSIONS: The study confirms that AOS or pathologies at the PAC often are not exactly described in CT report. In the context of foot trauma, attention should be paid to this region. Based on the presented differentiation criteria, a precise distinction can be made with the help of a CT.

Comparison of PI-RADS v1 and v2 for multiparametric MRI detection of prostate cancer with whole-mount histological workup as reference standard.

PURPOSE: The aim of this study was to compare Prostate Imaging Reporting and Data System (PI-RADS) versions v1 and v2 for the detection of prostate cancer (PCa) in multiparametric MRI (mpMRI) using whole-mount histological workup as reference standard. MATERIAL AND METHODS: MRI data of 40 patients with positive transrectal ultrasound-guided biopsy were analyzed retrospectively by two blinded readers (5 and 4 years' experience) with PI-RADS v1 and v2 for cancer-suspicious lesions. Prior to radical prostatectomy, patients had undergone IRB-approved mpMRI at 3 T according to PI-RADS recommendations: T2-weighted (T2w), diffusion-weighted (DWI) and dynamic contrast-enhanced (DCE) imaging. The reference standard was provided by whole-mount sections of the prostatectomy specimens. Versions v1 and v2 were compared with respect to sensitivity and positive predictive value (PPV) per lesion. Subgroups stratified by tumor location (peripheral vs. transition zone) and aggressiveness (high vs. low grade) were also analyzed. We also evaluated the concordance of the dominant MRI sequence in v2 (DWI or T2w) and the highest individual score under v1. Interobserver agreement for PI-RADS v1 and v2 was assessed by Cohen's kappa statistics. RESULTS: Reader 1 (R1) described 66 and Reader 2 (R2) 72 MRI lesions. The average Gleason score of 58 PCa lesions was 6.5 (range: 6 = 3 + 3 to 8 = 4 + 4), most of them (65.5%) located in the peripheral zone. PI-RADS v2 showed a trend towards lower sensitivities, but differences were not significant for both readers: R1 72.4% (v1) vs. 63.8% (v2) (P = 0.426) and R2 77.6% (v1) vs. 69.0% (v2) (P = 0.402). The trends were more pronounced in the transition zone and for low-grade cancers but remained insignificant (p-values from 0.313 to 0.691). Likewise, the apparent PPV differences, overall as well as in each zone, were not significant. Agreement between high-score v1 and dominant v2 sequence was 48% for R1 and 53% for R2. Cohen's κ of PCa detection for two readers was 0.48 for both v1 and v2. CONCLUSION: Our findings indicate that the simplified, zone-specific approach of PI-RADS v2 (2015) for MRI assessment of prostate cancer may not necessarily be better than the original v1 criteria (2012). In specific cases, a strict interpretation of v2 criteria may even lead to false-negative findings. Therefore, the current PI-RADS criteria should be reconsidered, despite the low statistical evidence here.

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.

Power of computed-tomography-defined sarcopenia for prediction of morbidity after pancreaticoduodenectomy.

BACKGROUND: The goal of our study was to evaluate the current approach in prediction of postoperative major complications after pancreaticoduodenectomy (PD), especially symptomatic pancreatic fistula (POPF), using parameters derived from computed tomography (CT). METHODS: Patients after PD were prospectively collected in a database of the local department of surgery and all patients with CT scans available were assessed in this study. CT parameters were measured at the level of the intervertebral disc L3/L4 and consisted of the areas of the visceral adipose tissue (AVAT), the diameters of the pancreatic parenchyma (DPP) and the pancreatic duct (DPD), the areas of ventral abdominal wall muscle (AMVEN), psoas muscle (AMPSO), paraspinal muscle (AMSPI), total muscle (AMTOT), as well as the mean muscle attenuation (MA) and skeletal muscle index (SMI). Mann-Whitney-U Test for two independent samples and binary logistic regression were used for statistical analysis. RESULTS: One hundred thirty-nine patients (55 females, 84 males) were included. DPD was 2.9 mm (Range 0.7-10.7) on median and more narrow in patients with complications equal to or greater stadium IIIb (p < 0.04) and severe POPF (p < 0.01). DPP median value was 17 (6.9-37.9) mm and there was no significant difference regarding major complications or POPF. AVAT showed a median value of 127.5 (14.5-473.0) cm2 and was significantly larger in patients with POPF (p < 0.01), but not in cases of major complications (p < 0.06). AMPSO, AMSPI, AMVEN and AMTOT showed no significant differences between major complications and POPF. MA was both lower in groups with major complications (p < 0.01) and POPF (p < 0.01). SMI failed to differentiate between patients with or without major complications or POPF. CONCLUSION: Besides the known factors visceral obesity and narrowness of the pancreatic duct, the mean muscle attenuation can easily be examined on routine preoperative CT scans and seems to be promising parameter to predict postoperative complications and POPF.

MRI assessment of changes in adipose tissue parameters after bariatric surgery.

Bariatric surgery and other therapeutic options for obese patients are often evaluated by the loss of weight, reduction of comorbidities or improved quality of life. However, little is currently known about potential therapy-related changes in the adipose tissue of obese patients. The aim of this study was therefore to quantify fat fraction (FF) and T1 relaxation time by magnetic resonance imaging (MRI) after Roux-en-Y gastric bypass surgery and compare the resulting values with the preoperative ones. Corresponding MRI data were available from 23 patients (16 females and 7 males) that had undergone MRI before (M0) and one month after (M1) bariatric surgery. Patients were 22-59 years old (mean age 44.3 years) and their BMI ranged from 35.7-54.6 kg/m2 (mean BMI 44.6 kg/m2) at M0. Total visceral AT volumes (VVAT-T, in L) were measured by semi-automatic segmentation of axial MRI images acquired between diaphragm and femoral heads. MRI FF and T1 relaxation times were measured in well-defined regions of visceral (VAT) and subcutaneous (SAT) adipose tissue using two custom-made analysis tools. Average BMI values were 45.4 kg/m2 at time point M0 and 42.4 kg/m2 at M1. Corresponding VVAT-T values were 5.94 L and 5.33 L. Intraindividual differences in both BMI and VVAT-T were highly significant (p<0.001). Average relaxation times T1VAT were 303.7 ms at M0 and 316.9 ms at M1 (p<0.001). Corresponding T1SAT times were 283.2 ms and 280.7 ms (p = 0.137). Similarly, FFVAT differences (M0: 85.7%, M1: 83.4%) were significant (p <0.01) whereas FFSAT differences (M0: 86.1, M1: 85.9%) were not significant (p = 0.517). In conclusion, bariatric surgery is apparently not only related to a significant reduction in common parameters of adipose tissue distribution, here BMI and total visceral fat volume, but also significant changes in T1 relaxation time and fat fraction of visceral adipose tissue. Such quantitative MRI measures may potentially serve as independent biomarkers for longitudinal and cross-sectional measurements in obese patients.

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.

Dicomflex: A novel framework for efficient deployment of image analysis tools in radiological research.

OBJECTIVE: Medical image processing tools in research are often developed from scratch without the use of predefined software structures, which potentially makes them less reliable and difficult to maintain. The objective here was to present and evaluate a novel framework (Dicomflex) for the deployment of tools with a uniform workflow, commonly encountered in medical image analysis. MATERIALS AND METHODS: The object-oriented code was developed using Matlab. Dicomflex applications follow the common workflow of image-slice selection, user interaction, image processing, result visualization and progression to next slice. The framework consists of three important classes that host functionality, two configuration files and a front end that displays images, graphs and resulting data. RESULTS: So far, three different research tools have been created under the new framework. In comparison with previous Matlab analysis tools used at our institution, users of Dicomflex tools subjectively considered the learning phase to be shorter and handling to be simpler and more intuitive. They also highlighted the benefit and comfort of the standardized interface and predefined workflow. The framework-inherent handling of software versions was considered highly beneficial for maintenance as well as data and software management at different project stages. The clear separation of framework-related and unrelated code allows for a fast and more direct design of new tools in well-defined steps. The flexibility of the framework translates to a wide range of image processing tasks, such as segmentation, region-of-interest (ROI) analyses or computation of functional parameter maps, but is limited to 2D datasets. CONCLUSION: Potential medical applications include the assessment of cardiac performance, detection of cerebrovascular disease or characterization of cancerous lesions. Dicomflex tools share a similar workflow and host the pertinent functions only. This may be relevant for many image processing needs in radiological research, where quick software deployment and reliability of results is essential.

Early Flow Disturbances of Tunnelled Haemodialysis Catheters and Topographic Landmarks in Chest X-Ray.

BACKGROUND/AIMS: The position of the tip of tunnelled haemodialysis (HD) catheters (THC) might influence flow characteristics during HD. In chest X-ray (CXR), carina-related landmarks may be practicable to verify the THC position, and tip-carina distance (TCD) might be useful to predict early-flow dysfunctions. METHODS: In this single-centre, retrospective study, the TCD and the angle between the distal catheter and the body vertical axis (tip-body vertical-angle [TVA]) was measured in 115 THC by post-procedure CXR with 2 investigators. The parameters were proved to be feasible by interrater-reliability and correlated with the incidence of flow-dysfunction within 10 days after insertion. RESULTS: Steep-aligned (TVA <40°, p < 0.01) and deep-ending catheters (TCD: right-sighted >1.5 cm or left-sighted >4.5 cm below the carina; p < 0.01) showed a significantly less dysfunction with a good interrater-reliability (R[TVA] = 0.8, R[TCD] = 0.9). CONCLUSIONS: Carina-related landmarks in CXR might be helpful to predict early-flow dysfunctions. However, randomized studies will be necessary to confirm this in fluoroscopic-guided placement during the insertion of THC.

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.

Cardiac Hematological Malignancies: Typical Growth Patterns, Imaging Features, and Clinical Outcome.

Cardiac hematological malignancies (CHMs) are rare entities and comprise lymphoma, leukemic infiltration, and extramedullary manifestation of multiple myeloma. The aim of this work is to summarize typical growth patterns, imaging features, and outcome parameters of CHM. Overall, 12 cases from 4 centers were reviewed retrospectively together with 604 cases from the literature. Cardiac hematological malignancies were mainly represented by B-cell lymphoma (70.0%). Other entities were rarer. Almost half of the patients showed involvement of multiple cardiac structures. Most commonly right atrium, right ventricle, pericardium, left atrium, and left ventricle were affected in decreased order of frequency. Cardiac hematological malignancies manifested with 3 growth patterns: intracaval masses, heart wall infiltration, and pericardial effusion. Several subtypes of CHM tended to present with different patterns. Clinical presentation is unspecific-frequent signs were dyspnea (54.6%), arrhythmias (30.5%), and thoracic pain (18.5%). Outcome of CHM is poor with mean survival of 283.6 days for leukemias, 260.1 days for T-cell non-Hodgkin lymphoma (NHL), 217.9 days for B-cell NHL, and 155.5 days for multiple myeloma.

Associations between 18F-FDG-PET, DWI, and DCE Parameters in Patients with Head and Neck Squamous Cell Carcinoma Depend on Tumor Grading.

Our purpose was to analyze associations between positron emission tomography (PET), diffusion weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging in patients with head and neck squamous cell carcinoma (HNSCC). The study involved 34 patients (9 women, 25 men, mean age: 56.7 ± 10.2 years). In all patients a simultaneous 18F-FDG-PET/MR was performed. DWI was obtained by using of an axial EPI sequence. Minimal ADC values (ADCmin), mean ADC values (ADCmean), and maximal ADC values (ADCmax) were estimated. DCE MRI was performed by using dynamic T1w DCE sequence. The following parameters were estimated: Ktrans, Ve , and Kep. Spearman's correlation coefficient was used to analyze associations between investigated parameters. In overall sample, ADCmean correlated significantly with Ve and Ktrans, ADCmin correlated with Ve , and ADCmax correlated with Ktrans and Ve . SUVmean tended to correlate slightly with Ktrans. In G1/2 tumors, only Ktrans correlated well with ADCmax and SUVmean. In G3 tumors, Ktrans correlated well with Kep and Ve . Ve showed significant correlations with ADCmean and ADCmax. Ktrans correlated with ADCmax. Kep was higher in cancers with N2/3 stages. Tumor metabolism, water diffusion, and tumor perfusion have complex relationships in HNSCC. Furthermore, these associations depend on tumor grading. Kep may predict lymphonodal metastasizing.

White Paper: Interventional MRI: Current Status and Potential for Development Considering Economic Perspectives, Part 2: Liver and Other Applications in Oncology.

Background MRI is attractive for guiding and monitoring interventional procedures due to its high intrinsic soft tissue contrast and the possibility to measure flow and cardiac function. Methods Technical solutions have been developed for all procedural steps including imaging guidance, MR-safe catheters and instruments and patient monitoring. This has led to widening of the clinical applications. Interventional MRI is becoming increasingly important for the treatment of patients suffering from malignant diseases. The detectability of masses and consequently their accessibility for biopsy is higher, compared to other modalities, due to the high intrinsic soft tissue contrast of MRI. Temperature-dependent sequences allow for minimally invasive and tissue-sparing ablation (A-0 ablation). Conclusion Interventional MRI has become established in the clinical routine for a variety of indications, including biopsies and tumor ablation. Since the economic requirement of covering costs by reimbursement is met and interventional MRI decreases the mortality and morbidity of interventional procedures, broader application of interventional MRI can be expected in the clinical routine in the future. Key points · Particularly for the treatment of oncological patients, interventional MRI is superior to other methods with respect to minimal invasiveness and tissue protection due to the ability to exactly determine tumor borders and to visualize and control the size of the ablation area on the basis of MR temperature measurement.. · Due to the better visualization of targets and the effects of ablation in tissue, interventional MRI can lower the mortality and morbidity associated with these interventions for many indications.. · The complex comparison of costs and reimbursement shows that this application can be performed in a cost-covering manner and broader application can be expected in the future.. Citation Format · Barkhausen J, Kahn T, Krombach GA et al. White Paper: Interventional MRI: Current Status and Potential for Development Considering Economic Perspectives, Part 2: Liver and Other Applications in Oncology. Fortschr Röntgenstr 2017; 189: 1047 - 1054.

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.

White Paper: Interventional MRI: Current Status and Potential for Development Considering Economic Perspectives, Part 1: General Application.

Background MRI is attractive for the guiding and monitoring of interventional procedures due to its high intrinsic soft tissue contrast and the possibility to measure physiologic parameters like flow and cardiac function. Method The current status of interventional MRI for the clinical routine was analyzed. Results The effort needed for the development of MR-safe monitoring systems and instruments initially resulted in the application of interventional MRI only for procedures that could not be performed by other means. Accordingly, biopsy of lesions in the breast, which are not detectable by other modalities, has been performed under MRI guidance for decades. Currently, biopsies of the prostate under MRI guidance are established in a similar fashion. At many sites blind biopsy has already been replaced by MR-guided biopsy or at least by the fusion of MR images with ultrasound. Cardiovascular interventions are performed at several centers for ablation as a treatment for atrial fibrillation. Conclusion Interventional MRI has been established in the clinical routine for a variety of indications. Broader application can be expected in the clinical routine in the future owing to the multiple advantages compared to other techniques. Key points · Due to the significant technical effort, MR-guided interventions are only recommended in the long term for regions in which MRI either facilitates or greatly improves the intervention.. · Breast biopsy of otherwise undetectable target lesions has long been established in the clinical routine. Prostate biopsy is currently being introduced in the clinical routine for similar reasons. Other methods such as MR-guided focused ultrasound for the treatment of uterine fibroids or tumor ablation of metastases represent alternative methods and are offered in many places.. · Endovascular MR-guided interventions offer advantages for a number of indications and have already been clinically established for the treatment of children with congenital heart defects and for atrial ablation at individual centers. Greater application can be expected in the future.. Citation format · Barkhausen J, Kahn T, Krombach GA et al. White Paper: Interventional MRI: Current Status and Potential for Development Considering Economic Perspectives, Part 1: General Application. Fortschr Röntgenstr 2017; 189: 611 - 623.

Systemic air embolism after endoscopy without vessel injury - A summary of reported cases.

INTRODUCTION: Systemic air embolism (SAE) is a rare but serious complication following endoscopic procedures. It may occur with or without direct vessel injury. The aim of this work is to review cases of SAE following endoscopy without proven vessel injury. METHODS: In this systematic review PubMed database was screened for SAE following endoscopy from 1990 to 2015. Only cases without proven major vessel injury were included in the analysis. Including one case of SAE after colonoscopy from our hospital the analysis comprised 40 cases. RESULTS: 60% of patients underwent ERCP, 33% gastroscopy and the remaining 7% other endoscopic procedures. Among patients suffering from SAE the majority had cerebral embolism (73%). In 46% of documented echocardiography a patent foramen ovale (PFO) has been confirmed as mechanism of paradoxical air embolism. Therapeutic approaches comprised most frequently hyperbaric oxygenation. In 35% of cases advanced life support was necessary whereas only 55% of patients survived SAE in total. CONCLUSION: SAE is a serious complication of endoscopic procedures with high morbidity and mortality. In patients with present PFO high awareness should be paid to informed consent for the risk of SAE, especially stroke. Cautiousness with sedation is necessary in those patients not to delay clinical recognition of neurological SAE symptoms.

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.

Correlations Between DCE MRI and Histopathological Parameters in Head and Neck Squamous Cell Carcinoma.

BACKGROUND: Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) can characterize perfusion and vascularization of tissues. DCE MRI parameters can differentiate between malignant and benign lesions and predict tumor grading. The purpose of this study was to correlate DCE MRI findings and various histopathological parameters in head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS: Sixteen patients with histologically proven HNSCC (11 cases primary tumors and in 5 patients with local tumor recurrence) were included in the study. DCE imaging was performed in all cases and the following parameters were estimated: Ktrans, Ve, Kep, and iAUC. The tumor proliferation index was estimated on Ki 67 antigen stained specimens. Microvessel density parameters (stained vessel area, total vessel area, number of vessels, and mean vessel diameter) were estimated on CD31 antigen stained specimens. Spearman's non-parametric rank sum correlation coefficients were calculated between DCE and different histopathological parameters. RESULTS: The mean values of DCE perfusion parameters were as follows: Ktrans 0.189 ± 0.056 min-1, Kep 0.390 ± 0.160 min-1, Ve 0.548 ± 0.119%, and iAUC 22.40 ± 12.57. Significant correlations were observed between Kep and stained vessel areas (r = 0.51, P = .041) and total vessel areas (r = 0.5118, P = .043); between Ve and mean vessel diameter (r = -0.59, P = .017). Cell count had a tendency to correlate with Ve (r = -0.48, P = .058). In an analysis of the primary HNSCC only, a significant inverse correlation between Ktrans and KI 67 was identified (r = -0.62, P = .041). Our analysis showed significant correlations between DCE parameters and histopathological findings in HNSCC.