Morphologic perfusion patterns and PI-RADSv2.1 in transition zone prostate cancer.

PURPOSE: To evaluate morphologic perfusion patterns in transition zone prostate cancer in multiparametric MRI controlled by in-bore MRI-guided prostate biopsy. METHODS: Two experienced radiologists evaluated MRI perfusion patterns in consensus from 321 biopsy cores from the transition zone in 141 patients. Transition zone cancer was present in 77 cores in 36 patients. Single early-phase perfusion images were evaluated separately for the presence of a transition zone prostate cancer (consensus tumor early perfusion). The proposed criteria for the perfusion pattern (asymmetry, signal strength, and homogeneity) were rated in consensus for each biopsy position in the presence of the T2w images including the markers of the biopsy trace. We analyzed receiver operating characteristic curves for the PI-RADSv2.1 score and the proposed perfusion pattern. RESULTS: A logistic regression model with PI-RADSv2.1 and perfusion patterns in early perfusion imaging improved the model fit significantly compared to a model containing only PI-RADSv2.1 (Likelihood Ratio Test, LR = 14.5, p < .001). The AUC was 0.96 for the multiple regression model compared to 0.92 for the PI-RADSv2.1 alone. The evaluation of homogeneity in single early-enhancement images is not inferior compared to the conventional DCE parameter of PI-RADSv2.1 (AUC 0.84 versus 0.83). CONCLUSION: Morphologic perfusion patterns significantly improve the diagnostic performance of PI-RADSv2.1 in TZ prostate cancer.

Impact of left atrial appendage morphology on thrombus formation in TAVI patients with atrial fibrillation.

PURPOSE: We aimed to correlate left atrial appendage (LAA) morphology with thrombus formation in patients with severe aortic valve stenosis and atrial fibrillation. METHODS: We analyzed LAA morphology and the prevalence of a thrombus in 231 patients with atrial fibrillation and severe aortic valve stenosis that were referred for pre-interventional CT scan before trans-catheter aortic valve implantation (TAVI) between 2016 and 2018. In addition, we documented neuro-embolic events depending on the presence of LAA thrombus within a follow-up of 18 months. RESULTS: The overall distribution of different LAA morphologies was chicken-wing 25.5%, windsock 51.5%, cactus 15.6% and cauliflower 7.4%. Compared to chicken-wing morphology, patients with non-chicken-wing morphology showed a significantly higher thrombus rate (OR: 2.48, 95%; CI 1.05 to 5.86, p = 0.043). Within the 50 patients with a LAA thrombus, we observed chicken-wing (14.0%), windsock (62.0%), cactus (16.0%) and cauliflower (8.0%) configuration. In patients with LAA thrombus those with chicken-wing configuration have a higher risk (42.9%) to develop neuro-embolic events compared to non-chicken-wing configuration (20.9%). CONCLUSION: We found a lower LAA thrombus rate in patients with chicken-wing morphology compared to patients with non-chicken-wing configuration. However, in the presence of thrombus, those patients with chicken-wing morphology showed a doubled risk for neuro-embolic events compared to patients with non-chicken-wing morphology. These results must be confirmed in larger trials but underline the importance of LAA evaluation in thoracic CT scans and could have an impact on the anticoagulation management.

Diffusion-weighted MRI and PET-CT in the follow up of chronic periaortitis.

Aim of the present study is to compare magnetic resonance imaging (MRI) and positron emission tomography (PET) parameters in the follow up of chronic periaortitis (CP), with a focus on changes in the apparent diffusion coefficient (ADC) and standardized uptake values (SUV). 127 patients with CP were treated in our urology between 2007 and 2017. We identified 14 patients with parallel abdominal MRI and PET-CT examinations before therapy and in the follow up resulting in a total of 56 examinations. Relative contrast uptake and diffusion-weighted MRI parameters were compared to SUV in the corresponding PET-CT examinationsand laboratory infection markers. All examined MRI and PET-CT parameters showed significant changes between basis and follow-up examinations. Median ADC values increased significantly (p < 0.001) in the follow up. SUVmax and the other MR parameter (contrast uptake, DWI-signal) declined significantly. We observed a strong negative correlation between ADC and SUVmax (rho: - 0.61; p < 0.001). In addition, we found an inverse correlation of ADC with the inflammation markers ESR (rho: - 0.64; p < 0.001) and CRP (rho: - 0.54; p = 0.001). MRI and PET-CT showed comparable results in the individual follow up of CP and compared to laboratory inflammation markers. Our data support MRI as first imaging modality due to absent radiation and the necessity of repetitive follow-up examinations in patients with CP.

CT-angiography of the aorta in patients with Marfan disease - High-pitch MDCT at different levels of tube voltage combined with Sinogram Affirmed Iterative Reconstruction.

OBJECTIVES: Aim of the study was the comparison of high-pitch dual-source CTA of the aorta acquired with different tube currents and methods of image reconstruction in patients with Marfan Disease (MFS). BACKGROUND: Patients with MFS receive repeatedly CT examinations of the entire aorta what leads to high cumulative lifetime radiation doses. Routine clinical use of low-kV-protocols in combination with iterative reconstruction for imaging of the aorta is still limited although this approach may be of great benefit for patients in need of serial follow-up scans. METHODS: 106 patients with MFS received CTA of the entire aorta in a 2nd generation dual-source Flash-CT at 120, 100 or 80 kV. 120 kV images were reconstructed with FBP, low-kV images with an IR algorithm (SAFIRE) at different noise reduction levels. CTDIvol, DLP and effective dose were analyzed. Quantitative image analysis included comparison of SNR, CNR and Noise levels. For qualitative analysis, two blinded readers assessed noise, contour delineation, contrast, overall image quality and diagnostic confidence. RESULTS: Effective dose was 9.4 (±1.5) mSv for 120 kV, 4.2 (±1.1) mSv for 100 kV and 1.9 (±0.42) mSv for 80 kV. 100 kV images showed the highest SNR and CNR values, followed by 80 kV and 120 kV. Qualitative image analysis showed the lowest scores for all evaluated aspects at 80 kV. Overall image quality and diagnostic confidence was excellent at all kV strengths. CONCLUSIONS: In MFS patients low-kV CT protocols with IR allow for CTA of the entire aorta in excellent image quality and diagnostic confidence with a dose reduction of up to 80% compared to 120 kV. For baseline CT, we recommend 100 kV, for follow-up CT scans 80 kV as tube voltage.

[Diagnostics and endovascular treatment of venous diseases]. / Diagnostik und endovaskuläre Therapie venöser Erkrankungen.

In venous disease, acute thromboses and chronic venous insufficiency have the highest health economics relevance. Duplex sonography is the first line diagnostic assessment tool, while cross-sectional imaging is employed as a supplementary method. Due to the availability and examination times computed tomography is preferred in the emergency setting and is supplemented by magnetic resonance imaging (MRI) for specific questions. Endovascular treatment procedures are increasingly becoming available in addition to classical conservative treatment methods.

Proximal culprit lesion and coronary artery occlusion independently predict the risk of microvascular obstruction in acute myocardial infarction.

Microvascular obstruction (MO) and coronary flow have been independently described to have a high prognostic impact after acute myocardial infarction (AMI). Their interdependence has not been precisely elucidated, so far. Aim of this study was to investigate the impact of coronary flow on the occurrence of MO in patients with AMI. 336 patients with revascularized AMI were examined by cardiac magnetic resonance imaging. Patients were categorised into two groups based on the presence of MO. Procedural characteristics and marker of infarct size were analyzed. MO was present in 110 (33 %) and absent in 226 (67 %) patients. Both groups differed significantly regarding pre- and post-interventional thrombolysis in myocardial infarction (TIMI) flow. After multivariable regression analysis pre-interventional TIMI-flow 0, proximal culprit lesion, post-interventional TIMI-flow

[Ductal adenocarcinoma and unusual differential diagnosis]. / Duktales Adenokarzinom und ungewöhnliche Differenzialdiagnosen.

Ductal pancreatic adenocarcinoma is by far the most common solid tumor of the pancreas. It has a very poor prognosis, especially in the more advanced stages which are no longer locally confined. Due to mostly unspecific symptoms, imaging is key in the diagnostic process. Because of the widespread use of imaging techniques, incidental findings are to a greater extent discovered in the pancreas, which subsequently entail further work-up. Ductal pancreatic adenocarcinoma can be mimicked by a large number of different lesions, such as anatomical variants, peripancreatic structures and tumors, rarer primary solid pancreatic tumors, cystic tumors, metastases or different variants of pancreatitis. Additionally, a number of precursor lesions can be differentiated. The correct classification is thus important as an early diagnosis of ductal pancreatic adenocarcinoma is relevant for the prognosis and because the possibly avoidable treatment is very invasive. All major imaging techniques are principally suitable for pancreatic imaging. In addition to sonography of the abdomen, usually the baseline diagnostic tool, computed tomography (CT) with its superior spatial resolution, magnetic resonance imaging (MRI) with its good soft tissue differentiation capabilities, possibly in combination with MR cholangiopancreatography (MRCP), endosonography with its extraordinary spatial resolution, conceivably with additional endoscopic retrograde CP or the option of direct biopsy and finally positron emission tomography CT (PET-CT) as a molecular imaging tool are all particularly useful modalities. The various techniques all have its advantages and disadvantages; depending on the individual situation they may need to be combined.

[Percutaneous access for endovascular therapy of PAOD. Femoral, popliteal and pedal]. / Perkutane Zugänge zur endovaskulären PAVK-Therapie. Femoral, popliteal, pedal.

BACKGROUND: Percutaneous interventions in patients with peripheral arterial occlusive disease (PAOD) are usually performed from an antegrade or retrograde transfemoral arterial access; however, sometimes chronic femoropopliteal and crural occlusions cannot be negotiated via this route with traditional standard methods. OBJECTIVES: Description and evaluation of transfemoral, transpopliteal and transpedal vascular approaches for the treatment of advanced PAOD. MATERIAL AND METHODS: A literature review of available studies on endovascular interventions with distal retrograde access was carried out. RESULTS: Most complex arterial occlusions can be treated by employing modern subintimal procedures and/or additional retrograde approaches. The success rate also depends on the expertise with the appropriate technique and materials used. CONCLUSION: The transfemoral access remains the first choice for the treatment of patients with PAOD. Additional retrograde approaches from a more distal access constitute an alternative after failure of antegrade intervention attempts.

[Young Women - Problematic Patients in Vascular Surgery]. / Junge Frauen - Problempatientinnen in der Gefäßchirurgie.

The treatment of peripheral arterial disease (PAD) in young women between 40 and 60 years of age represents a difficult challenge for the vascular surgeon. Excessive smoking, an early menopause and the unfavourable anatomic proportions of thinner arterial vessels or vein grafts during peripheral bypass-surgery lead to a higher rate of complications or re-occlusion following invasive therapy in comparison to male patients. A special anatomic manifestation appearing nearly only in women around the 6th decade is the so-called aortoiliac hypoplastic syndrome with a high rate of re-occlusion after balloon-dilatation or local thrombendarteriectomy and bypass grafting, respectively. Variabilities in coagulation and the undertreatment of classical risk factors of PAD by medical drugs lead to poorer results in the treatment of PAD in young women. Therefore a conservative therapy - whenever feasible - should be the first choice for treating PAD in young women.

Diffusion-weighted MRI in the follow-up of chronic periaortitis.

OBJECTIVE: To evaluate the usefulness of diffusion-weighted MRI (DWI) for the assessment of the intraindividual follow-up in patients with chronic periaortitis (CP) under medication. METHODS: MRI data of 21 consecutive patients with newly diagnosed untreated disease were retrospectively examined before and after medical therapy, with a median follow-up of 16 weeks. DWI parameters [b800 signal, apparent diffusion coefficient (ADC) values] of the CP and psoas muscle were analysed together with the extent and contrast enhancement. Pre- and post-treatment laboratory inflammation markers were acquired parallel to each MR examination. RESULTS: Statistically significant lower b800 signal intensities (p ≤ 0.0001) and higher ADC values (p ≤ 0.0001) were observed after medical treatment within the fibrous periaortic tissue. Extent and contrast enhancement of the CP showed also a statistically significant decrease (p ≤ 0.0001) in the follow-up examinations, while the control parameters within the psoas muscle showed no differences. CONCLUSION: DWI seems to be a useful method for the evaluation of response to treatment without contrast agents. The technique may be helpful in the assessment of disease activity to guide further therapeutic strategies. ADVANCES IN KNOWLEDGE: DWI detects significant differences in the intraindividual follow-up of CP under medical therapy.

Diffusion-weighted MRI in the follow-up of chronic periaortitis.

OBJECTIVE:: To evaluate the usefulness of diffusion-weighted MRI (DWI) for the assessment of the intraindividual follow-up in patients with chronic periaortitis (CP) under medication. METHODS:: MRI data of 21 consecutive patients with newly diagnosed untreated disease were retrospectively examined before and after medical therapy, with a median follow-up of 16 weeks. DWI parameters [b800 signal, apparent diffusion coefficient (ADC) values] of the CP and psoas muscle were analysed together with the extent and contrast enhancement. Pre- and post-treatment laboratory inflammation markers were acquired parallel to each MR examination. RESULTS:: Statistically significant lower b800 signal intensities (p ≤ 0.0001) and higher ADC values (p ≤ 0.0001) were observed after medical treatment within the fibrous periaortic tissue. Extent and contrast enhancement of the CP showed also a statistically significant decrease (p ≤ 0.0001) in the follow-up examinations, while the control parameters within the psoas muscle showed no differences. CONCLUSION:: DWI seems to be a useful method for the evaluation of response to treatment without contrast agents. The technique may be helpful in the assessment of disease activity to guide further therapeutic strategies. ADVANCES IN KNOWLEDGE:: DWI detects significant differences in the intraindividual follow-up of CP under medical therapy.

Prenatal radiation exposure: dose calculation.

The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero x-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties. • Radiation exposure of the unborn child can result in both deterministic as well as stochastic damage und hitherto should be avoided or reduced to a minimum.• In case of radiation a suitable hygiene consultation may be necessary.• For risk assessment a three-stage concept is applied, which, depending on the radiation exposure, estimates or calculates the dose for the unborn child.• The radiologist plays a crucial role as a competent advisor and provider of reliable expert information. Citation Format: • Scharwächter C, Röser A, Schwartz CA et al. Prenatal Radiation Exposure: Dose Calculation. Fortschr Röntgenstr 2015; 187: 338 - 346.

Diagnosis and treatment of insufficient dialysis vascular access.

A wide variety of diagnostic and minimally invasive modalities is currently available to radiologists for providing sufficient medical care for dialysis patients. In addition to clinical examination, ultrasound is the first line imaging method in suspected dialysis vascular access dysfunction. The percutaneous approach is the primarily recommended therapeutic option in many cases. This article reviews the current diagnostic and therapeutic methods in dialysis vascular access insufficiency.

[Endovascular therapy of an iatrogenic renal-artery-perforation after fenestrated-aortic-repair (fEVAR)]. / Endovaskuläre Therapie einer iatrogenen Nierenarterienperforation nach fenestrierter Aortenprothese (fEVAR).

HISTORY AND ADMISSION FINDINGS: A 75-year-old patient was initially hospitalized for therapy-evaluation of a an acquaint infrarenal abdominal-aortic-aneurysm, with a maximum diameter of 5.3 cm. Medical history showed a known contained rupture of the aneurysm. Except for a substituted Hypothyroidism and a COPD Stadium II (GOLD), there were no other previous diseases known. EXAMINATIONS: Laboratory showed a slight normochrome, normocytic anemia (hemoglobin 13 g/dl, MCV and MCH were normal) together with a decreased total amount of erythrocytes of 3.89/pl. TSH value was increased significantly at 7.960 mU/l. Initially creatinine was measured at 1.02 mg/dl. Sonography and CT-scan of the abdominal vessels had shown no new insights other than the aneurysm of the abdominal aorta. A surgical revision was indicated. TREATMENT AND COURSE: After primarily uncomplicated implantation of a fenestrated EVAR, the patient showed a progressive hemoglobin loss concomitant with a considerable increase of renal retention parameters. A "spurium"/false aneurysm of the right renal artery was found, which moreover showed a retroperitoneal bleeding. The patient subsequently underwent successful endovascular therapy in our clinic and was dismissed from the hospital in good condition and without further complications. Follow up controls showed no signs of new pathologies. CONCLUSION: "Direct" post-operative complications after EVAR are a rarity. In our case, the interventional endovascular approach of the bleeding from the right renal artery was a successful and sufficient treatment of the potentially life-threatening complication.

[Intussusception after Billroth II operation fifty years ago - an unusual cause for ileus]. / Invagination nach Billroth-II-Operation vor 50 Jahren - eine ungewöhnliche Ursache für einen Ileus.

HISTORY: A 77-year-old woman presented with occasional vomiting of hematin but no further complaints. 50 years ago a partial gastrectomy after Billroth II had been performed due to a gastric ulcer. INVESTIGATIONS: The physical examination revealed no pathologic findings. All laboratory values, including hemoglobin (HB), were in normal range. The gastroscopic examination showed traces of hematin in the stomach and in the efferent and afferent loop.  The Braun anastomosis could not be delineated. No other pathologic findings were noted. TREATMENT AND COURSE: At the request of the patient additional regular controls of hemoglobin were planned on an outpatient basis. In case of hemoglobin decrease, further treatment should be arranged. Two days after discharge the patient was presented with sudden massive abdominal pain and vomiting. Clinical examination confirmed the assumption of mechanical ileus. An emergency abdominal CT showed an intussusception of a small bowel loop into the Braun anastomosis as the ileus trigger. A laparotomy was carried out immediately after the CT. Because of severe ischemic damage of the intussuscepted loop, an "en bloc" resection of the loop including the Braun anastomosis including reanastomosis had to be carried out. CONCLUSION: Intussusception is primarily a childhood disease, occurring in adults only in about 5% of cases. Postoperative intussusception is a rare complication after gastric surgery.Especially because of its exceptionality the diagnosis of intussusception in adulthood can be difficult. Crucial herein is to have intussusception in mind in the differential diagnostic pathway of a post gastric surgery ileus.

[Experimental early detection of acute mesenteric ischemia with functional MRI (DWI) and parallel imaging]. / Experimentelle Frühdiagnostik der akuten mesenterialen Ischämie mittels diffusionsgewichteter MRT (DWI) und paralleler Bildgebung.

PURPOSE: To evaluate the feasibility of diagnosing in statu nascendi mesenteric ischemia using diffusion-weighted imaging (DWI) in a porcine model. All experiments were approved by the animal care committee at the district administration. MATERIALS AND METHODS: Mesenteric blood supply was studied in ten healthy female pigs (weight ~50 kg) with artificially induced mesenteric ischemia. In the DSA technique a branch of the superior mesenteric artery was embolized with tissue glue or small particles. DWI was performed using a 1.5 T MR scanner before embolization and 30 and 60 minutes after embolization using a 32-channel receiver coil. ADC maps were calculated for all animals. The findings were correlated to angiographic and autoptic findings. The image quality of DWI was assessed by means of SNR measurements and diagnostic impact by CNR measurements. RESULTS: Embolization of the mesenteric branches was technically successful in all cases. DWI of the bowel was feasible with the applied sequences. In all animals, DWI displayed distinct cytotoxic edema as the earliest sign of ischemia thirty minutes after induction of ischemia. Furthermore, DWI yielded a distinct reduction in the water diffusion coefficient in all animals. Variance analysis showed good correlation between CNR measurements and infarction areas. Autoptic findings could confirm the detected infarction areas by DWI. CONCLUSION: DWI using parallel imaging techniques is feasible for the early detection of acute mesenteric ischemia. The presented DWI results offer encouraging prospects regarding more rapid disease diagnosis.