Age- and Sex-Specific Reference Values for Renal Volume and Association with Risk Factors for Chronic Kidney Disease in a General Population-An MRI-Based Study.

BACKGROUND: Renal volume (RV) is associated with renal function and with a variety of cardiovascular risk factors (CVRFs). We analysed RV using magnetic resonance imaging (MRI) in a large population-based study (Study of Health in Pomerania; SHIP-TREND) to find sex- and age-specific reference values for RV and to test the influence of several markers on RV. The main objective is to describe reference values for RV in people from the general population without kidney disease. METHODS: 1815 participants without kidney disease (930 women) aged 21-81 years were included in our study. Right and left RV with and without body surface area (BSA) indexation were compared among three age groups (22-39 years, 40-59 years, 60-81 years) by median and interquartile range and tested separately in women and men. RESULTS: The estimated glomerular filtration rate (eGFR), serum uric acid, and right and left RV were higher in men compared to women (all p < 0.001). Left kidneys were larger than right kidneys (both sexes). With age, RV showed a continuously decreasing trend in women and an upside-down U-shaped relation in men. In multivariable linear regression models, current smoking (ß = 14.96, 95% CI 12.12; 17.79), BSA (ß = 97.66, 95% CI 90.4; 104.93), diastolic blood pressure (ß = 0.17, 95% CI 0.01; 0.32), and eGFR (ß = 0.57, 95% CI 0.50; 0.65) were positively associated with both left and right RV, whereas uric acid (ß = -0.03, 95% CI -0.05; -0.01) showed an inverse association with RV. Interestingly, the same eGFR correlated with higher RV in men compared to women. CONCLUSION: Reference values for RV are different for age groups and sex. For any given age, female kidneys are smaller than male kidneys. RV associates positively with eGFR, but for any chosen eGFR, renal volume in females is lower compared to males. RV decreases with age, but in men showed a U-shaped correlation. This may reflect hyperfiltration and glomerular hypertrophy associated with the presence of CVRF in middle-aged males.

Virtual inverted classroom to replace in-person radiology lectures at the time of the COVID-19 pandemic - a prospective evaluation and historic comparison.

BACKGROUND: In the time of the coronavirus disease 2019 (COVID-19) pandemic, in-person lectures had to be shifted to online learning. This study aimed to evaluate students' and lecturers' perception and effectiveness of a virtual inverted classroom (VIC) concept on clinical radiology in comparison to a historic control. METHODS: In the winter semester 2020/21, 136 fourth year medical students who completed the clinical radiology VIC during the pandemic, were included in the single centre, prospective study. Results were compared with a historic control that had finished the physical inverted classroom (PIC) in the immediately preceding year. The VIC consisted of an initial phase of self-determined preparation with learning videos and a second interactive phase of clinical case studies alternating between the virtual lecture hall and virtual buzz groups. At the end of the lecture series, students rated the lecture on a scale of 1 (most positive assessment) to 6 (most negative assessment) through an online survey platform. Additionally, they reported their impressions in free-form text. Lecturers were invited to comment on the VIC in a group interview. Main outcomes were final grades and student perception of the VIC. RESULTS: Students' general impression of VIC was lower than that of PIC (median value of 3 [IQR 4, 2] and 1 [IQR 0, 0], p < 0.001), respectively, p < 0.001). The highest rating was achieved concerning use of the audience response system (median 1 [IQR 1, 0]), and the lowest concerning the buzz groups (median 4 [IQR 5, 3]). Students stated that they would have appreciated more details on reading images, greater focus on plenary case studies, and provision of exam related scripts. Lecturers would have liked better preparation by students, more activity of students, and stronger assistance for group support. Exam grades after VIC were better than after PIC (median 1 [IQR 2, 1] and 2 [IQR 2,1], respectively, p < 0.001). CONCLUSIONS: Students' overall perception of VIC was satisfactory, although worse than PIC. Final grades improved compared to PIC. Provided an adapted buzz group size and support, VIC may serve as complement in medical education once the pandemic is over.

Association between hepatic fat and subclinical vascular disease burden in the general population.

OBJECTIVE: It is still controversial if increased hepatic fat independently contributes to cardiovascular risk. We aimed to assess the association between hepatic fat quantified by MRI and various subclinical vascular disease parameters. DESIGN: We included two cross-sectional investigations embedded in two independent population-based studies (Study of Health in Pomerania (SHIP): n=1341; Cooperative Health Research in the Region of Augsburg (KORA): n=386). The participants underwent a whole-body MRI examination. Hepatic fat content was quantified by proton-density fat fraction (PDFF). Aortic diameters in both studies and carotid plaque-related parameters in KORA were measured with MRI. In SHIP, carotid intima-media thickness (cIMT) and plaque were assessed by ultrasound. We used (ordered) logistic or linear regression to assess associations between hepatic fat and subclinical vascular disease. RESULTS: The prevalence of fatty liver disease (FLD) (PDFF >5.6%) was 35% in SHIP and 43% in KORA. In SHIP, hepatic fat was positively associated with ascending (ß, 95% CI 0.06 (0.04 to 0.08)), descending (0.05 (0.04 to 0.07)) and infrarenal (0.02 (0.01 to 0.03)) aortic diameters, as well as with higher odds of plaque presence (OR, 95% CI 1.22 (1.05 to 1.42)) and greater cIMT (ß, 95% CI 0.01 (0.004 to 0.02)) in the age-adjusted and sex-adjusted model. However, further adjustment for additional cardiometabolic risk factors, particularly body mass index, attenuated these associations. In KORA, no significant associations were found. CONCLUSIONS: The relation between hepatic fat and subclinical vascular disease was not independent of overall adiposity. Given the close relation of FLD with cardiometabolic risk factors, people with FLD should still be prioritised for cardiovascular disease screening.

Impact of a Heutagogical, Multimedia-Based Teaching Concept to Promote Self-Determined, Cooperative Student Learning in Clinical Radiology.

PURPOSE: To date, didactic lecturing is a common method of university medical training. However, higher levels of competence to solve complex issues are hardly to be achieved with a largely passive learning style. We established and evaluated a heutagogical blended learning concept to investigate self-determined learning with a multimedia-based, interactive approach in the lecture room to teach clinical radiology. MATERIALS AND METHODS: In the 2019/2020 winter semester, we included 266 medical students in their fourth academic year in our prospective, observational study. Students participated in a series of 11 radiological lectures given by 10 lecturers. They were requested to prepare for lectures by watching learning videos. During the lecture, students had to answer key-feature questions (KFQ) in small groups and to jointly submit their answers by means of an audience response system (ARS). After each lecture and the exam, we conducted surveys and compared results with a historical control group. A focus group interview with lecturers was performed after conclusion of the lecture series. RESULTS: The students' overall impression of the "flipped classroom" concept and their examination grades were superior to historical controls (overall impression: 1.5 [95 % CI 1.4-1.6] vs. 2.7 [95 % CI 2.5-2.9] rated on a scale from 1 to 6, p < 0.001; examination grades: 1.8 [95 % CI 1.7-1.9] vs. 2.0 [95 % CI 1.9-2.0] rated on a scale from 1 to 5, p < 0.001). Most students agreed that learning videos (76.6 %), ARS (88.5 %), KFQ (76.5 %), and solution-oriented small group discussions (83.7 %) were useful. Lecturers stated an improved convergence of demands on learning and clinical competence. However, they also emphasized an increased initial effort for implementation. CONCLUSION: Students rated the overall benefit from the heutagogical "flipped classroom" concept as high. Examination grades improved. According to lecturers, the "flipped classroom" concept better matched later professional demands than traditional lectures. KEY POINTS: · The benefit of the "flipped classroom" concept for radiological lectures was rated high by students.. · Most students were satisfied with the multimedia and interactive elements of lectures.. · Lecturers considered heutagogical learning demands as appropriate for later clinical requirements.. CITATION FORMAT: · Teichgräber U, Ingwersen M, Mentzel H et al. Impact of a Heutagogical, Multimedia-Based Teaching Concept to Promote Self-Determined, Cooperative Student Learning in Clinical Radiology. Fortschr Röntgenstr 2021; 193: 701 - 711.

Local Intra-arterial Vasodilator Infusion in Non-Occlusive Mesenteric Ischemia Significantly Increases Survival Rate.

PURPOSE: To investigate the outcome of local intra-arterial papaverine infusion therapy in patients with non-occlusive mesenteric ischemia (NOMI), and factors influencing survival, in comparison with a conservative approach. METHODS: From 2013 to 2019, patients with NOMI confirmed by imaging were included in a retrospective two-center study. According to different in-house standard procedures, patients were treated in each center either conservatively or interventionally by a standardized local infusion of intra-arterial papaverine into the splanchnic arteries. Thirty-day mortality and factors influencing the outcome, such as different demographics and laboratories, were compared between groups using Kaplan-Meier survival analysis and Cox regression, respectively. RESULTS: A total of 66 patients with NOMI were included, with n = 35 treated interventionally (21 males, mean age 67.7 ± 12.3 years) and n = 31 treated conservatively (18 females, mean age 71.6 ± 9.6 years). There was a significant difference in 30-day mortality between the interventional (65.7%; 12/35 survived) and the conservative group (96.8%; 1/31 survived) (hazard ratio 2.44; P = 0.005). Thresholds associated with a worse outcome of interventional therapy are > 7.68 mmol/l for lactate, < 7.31 for pH and < - 4.55 for base excess. CONCLUSION: Local intra-arterial papaverine infusion therapy in patients with NOMI significantly increases survival rate in comparison with conservative treatment. High lactate levels, low pH and high base excess, and high demand for catecholamines are associated with a poor outcome. LEVEL OF EVIDENCE: Level III.

Prevalence and risk factors of perirenal hyperintensities on T2-weighted MR imaging.

OBJECTIVES: To assess the prevalence and severity of perirenal hyperintensities (PRHs) on T2-weighted magnetic resonance imaging (MRI) and their risk factors in the general population. METHODS: 1752 participants (910 women, 842 men, median age: 52 years) of the Study of Health in Pomerania were included. A visual classification system was established to assess the severity of PRHs (stage 0: no PRHs visible to stage 3: extensive PRHs visible). The MRI-derived thickness of the perirenal and posterior pararenal space and additional risk factors were determined and associated with PRH stages. RESULTS: The overall prevalence of PRHs was 40.7% and was higher in men than in women. PRHs were more common around the left compared to the right kidney (p < 0.001). On both sides, the presence of PRHs was associated with age (p < 0.001). Multivariable-adjusted regression models revealed male sex (OR = 13.2, 95%CI 9.7; 17.9, p < 0.001), older age (OR = 1.1, 95%CI 1.1; 1.1, p < 0.001), higher body mass index (BMI; OR = 1.1, 95%CI 1.0; 1.1, p < 0.001), current smoking status (OR = 1.9, 95%CI 1.4; 2.6, p < 0.001), and greater thickness of the posterior pararenal space (OR = 1.2, 95%CI 1.2; 1.2, p < 0.001) as independent significant risk factors of left-sided PRHs. The same risk factors were confirmed for right PRHs. Glomerular filtration rate was not associated with PRHs on either sides (OR = 1.00, 95%CI 1.0;1.0, p > 0.05). CONCLUSIONS: PRHs are common in the general population, with a higher prevalence in men, elderly individuals, and around the left kidney. Furthermore, BMI, posterior pararenal space thickness, and current smoking, but not renal function itself, are associated with the presence of PRHs.

Software-based noise reduction in cranial magnetic resonance imaging: Influence on image quality.

OBJECTIVES: To investigate acoustic noise reduction, image quality and white matter lesion detection rates of cranial magnetic resonance imaging (MRI) scans acquired with and without sequence-based acoustic noise reduction software. MATERIAL AND METHODS: Thirty-one patients, including 18 men and 13 women, with a mean age of 58.3±14.5 years underwent cranial MRI. A fluid-attenuated inversion recovery (FLAIR) sequence was acquired with and without acoustic noise reduction using the Quiet Suite (QS) software (Siemens Healthcare). During data acquisition, peak sound pressure levels were measured with a sound level meter (Testo, Typ 815). In addition, two observers assessed subjective image quality for both sequences using a five-point scale (1 very good-5 inadequate). Signal-to-noise ratio (SNR) was measured for both sequences in the following regions: white matter, gray matter, and cerebrospinal fluid. Furthermore, lesion detection rates in white matter pathologies were evaluated by two observers for both sequences. Acoustic noise, image quality including SNR and white matter lesion detection rates were compared using the Mann-Whitney-U-test. RESULTS: Peak sound pressure levels were slightly but significantly reduced using QS, P≤0.017. Effective sound pressure, measured in Pascal, was decreased by 19.7%. There was no significant difference in subjective image quality between FLAIR sequences acquired without/with QS: observer 1: 2.03/2.07, P = 0.730; observer 2: 1.98/2.10, P = 0.362. In addition, SNR was significantly increased in white matter, P≤0.001, and gray matter, P = 0.006, using QS. The lesion detection rates did not decline utilizing QS: observer 1: P = 0.944 observer 2: P = 0.952. CONCLUSIONS: Sequence-based noise reduction software such as QS can significantly reduce peak sound pressure levels, without a loss of subjective image quality and increase SNR at constant lesion detection rates.

Reference values of vessel diameters, stenosis prevalence, and arterial variations of the lower limb arteries in a male population sample using contrast-enhanced MR angiography.

INTRODUCTION: Morphological characterization of leg arteries is of significant importance to detect vascular remodeling triggered by atherosclerotic changes. We determined reference values of vessel diameters and assessed prevalence of stenosis and arterial variations of the lower limb arteries in a healthy male population sample. METHODS: Gadolinium-enhanced magnetic resonance angiography at 1.5 Tesla was performed in 756 male participants (median age = 52 years, range = 21-82 years) of the population-based Study of Health in Pomerania. Vessel diameters were measured in 9 predefined segments of the pelvic and leg arteries and 95th percentiles were used for upper reference values of means of left and right side arteries. RESULTS: Reference values of vascular diameters decreased from proximal to distal arteries: common iliac = 1.18cm; internal iliac = 0.75cm; external iliac = 1.03cm; proximal femoral = 1.02cm; distal femoral = 0.77cm; popliteal = 0.69cm; anterior tibial = 0.42cm; posterior tibial = 0.38cm; fibular = 0.40cm. Body-surface area indexed reference values increased with age in all segments. A number of 53 subjects (7.0%) had at least one stenosis, mainly in the lower leg arteries anterior tibial (n = 28, 3.7%), posterior tibial (n = 18, 2.4%) and fibular (n = 20, 2.6%). The risk of stenosis increased considerably with age (odds ratio = 1.08; p<0.001). The most common arterial variant was type I-A in both legs (n = 620, 82%). CONCLUSION: We present reference values for different pelvic and leg artery segment diameters in men that decrease from proximal to distal and increase with age. Stenoses were most prevalent in lower leg arteries and type I-A was the most common variant in the lower leg.

Prevalence of renal cysts and association with risk factors in a general population: an MRI-based study.

PURPOSE: To assess the prevalence and size of renal cysts and to analyze associated risk factors in a general population using magnetic resonance imaging (MRI). METHODS: Data of 2063 participants (1052 women) of the Study of Health in Pomerania who underwent whole-body MRI were included. Renal cyst prevalence was calculated separately for men and women and for 10-year age groups. The association between risk factors and occurrence of renal cysts was estimated. RESULTS: The prevalence of renal cysts was 27% and higher in men (34%) than in women (21%; p < 0.001). Renal cyst prevalence increased from 14% in the youngest age group (20-29 years) to 55% in the oldest age group (≥ 70 years) for men and from 7% to 43% for women (both p < 0.001). In the subset of participants with renal cysts, the total mean number was higher in men (1.9) compared to women (1.6, p = 0.012) and was significantly associated with age. Mean renal cyst size was higher in men (1.50 cm) compared to women (1.18 cm, p < 0.001). Male sex (OR 1.83, 95% CI 1.47; 2.26), older age (OR 1.05, 95% CI 1.04; 1.06, per 1-year increment), and hypertension (OR 1.27, 95% CI 1.00; 1.61) were associated with higher renal cyst prevalence. In additional analyses, current smoking and ex-smoking showed a significantly higher risk for renal cysts (OR 1.47, 95% CI 1.05; 2.05 and OR 1.38, 95% CI 1.04; 1.82, respectively). CONCLUSIONS: The prevalence, number, and mean size of renal cysts are higher in men compared to women and are associated with age. In addition, renal cyst prevalence is higher in hypertensive and smoking subjects.

Pulmonary emphysema is a predictor of pneumothorax after CT-guided transthoracic pulmonary biopsies of pulmonary nodules.

PURPOSE: Pneumothoraces are the most frequently occurring complications of CT-guided percutaneous transthoracic pulmonary biopsies (PTPB). The aim of this study was to evaluate the influence of pre-diagnostic lung emphysema on the incidence and extent of pneumothoraces and to establish a risk stratification for the evaluation of the pre-procedure complication probability. MATERIAL AND METHODS: CT-guided PTPB of 100 pre-selected patients (mean age 67.1±12.8 years) were retrospectively enrolled from a single center database of 235 PTPB performed between 2012-2014. Patients were grouped according to pneumothorax appearance directly after PTPB (group I: without pneumothorax, n = 50; group II: with pneumothorax, n = 50). Group II was further divided according to post-interventional treatment (group IIa: chest tube placement, n = 24; group IIb: conservative therapy, n = 26). For each patient pre-diagnostic percentage of emphysema was quantified using CT density analysis. Emphysema stages were compared between groups using bivariate analyses and multinomial logistic regression analyses. RESULTS: Emphysema percentage was significantly associated with the occurrence of post-interventional pneumothorax (p = 0.006). Adjusted for potential confounders (age, gender, lesion size and length of interventional pathway) the study yielded an OR of 1.07 (p = 0.042). Absolute risk of pneumothorax increased from 43.4% at an emphysema rate of 5% to 73.8% at 25%. No differences could be seen in patients with pneumothorax between percentage of emphysema and mode of therapy (p = 0.721). CONCLUSION: The rate of lung emphysema is proportionally related to the incidence of pneumothorax after CT-guided PTPB and allows pre-interventional risk stratification. There is no association between stage of emphysema and post-interventional requirement of chest tube placement.

Diagnosis and Differential Diagnosis of Hydrocephalus in Adults.

Purpose Hydrocephalus is caused by an imbalance of production and absorption of cerebrospinal fluid (CSF) or obstruction of its pathways, resulting in ventricular dilatation and increased intracranial pressure. Imaging plays a crucial role in the diagnosis, differential diagnosis and planning of treatment. Methods This review article presents the different types of hydrocephalus und their typical imaging appearance, describes imaging techniques, and discusses differential diagnoses of the different forms of hydrocephalus. Results and Conclusion Imaging plays a central role in the diagnosis of hydrocephalus. While magnetic resonance (MR) imaging is the first-line imaging modality, computed tomography (CT) is often the first-line imaging test in emergency patients. Key points · Occlusive hydrocephalus is caused by obstruction of CSF pathways.. · Malabsorptive hydrocephalus is caused by impaired CSF absorption.. · The MR imaging protocol should always include sagittal high-resolution T2-weighted images.. · When an inflammatory etiology is suspected, imaging with contrast agent administration is necessary.. Citation Format · Langner S, Fleck S, Baldauf J et al. Diagnosis and Differential Diagnosis of Hydrocephalus in Adults. Fortschr Röntgenstr 2017; 189: 728 - 739.

Prevalence of Fatty Liver Disease and Hepatic Iron Overload in a Northeastern German Population by Using Quantitative MR Imaging.

Purpose To quantify liver fat and liver iron content by measurement of confounder-corrected proton density fat fraction (PDFF) and R2* and to identify clinical associations for fatty liver disease and liver iron overload and their prevalence in a large-scale population-based study. Materials and Methods From 2008 to 2013, 2561 white participants (1336 women; median age, 52 years; 25th and 75th quartiles, 42 and 62 years) were prospectively recruited to the Study of Health in Pomerania (SHIP). Complex chemical shift-encoded magnetic resonance (MR) examination of the liver was performed, from which PDFF and R2* were assessed. On the basis of previous histopathologic calibration, participants were stratified according to their liver fat and iron content as follows: none (PDFF, ≤5.1%; R2*, ≤41.0 sec-1), mild (PDFF, >5.1%; R2*, >41 sec-1), moderate (PDFF, >14.1%; R2*, >62.5 sec-1), high (PDFF: >28.0%; R2*: >70.1 sec-1). Prevalence of fatty liver diseases and iron overload was calculated (weighted by probability of participation). Clinical associations were identified by using boosting for generalized linear models. Results Median PDFF was 3.9% (range, 0.6%-41.5%). Prevalence of fatty liver diseases was 42.2% (1082 of 2561 participants); mild, 28.5% (730 participants); moderate, 12.0% (307 participants); high content, 1.8% (45 participants). Median R2* was 34.4 sec-1 (range, 14.0-311.8 sec-1). Iron overload was observed in 17.4% (447 of 2561 participants; mild, 14.7% [376 participants]; moderate, 0.8% [20 participants]; high content, 2.0% [50 participants]). Liver fat content correlated with waist-to-height ratio, alanine transaminase, uric acid, serum triglycerides, and blood pressure. Liver iron content correlated with mean serum corpuscular hemoglobin, male sex, and age. Conclusion In a white German population, the prevalence of fatty liver diseases and liver iron overload is 42.2% (1082 of 2561) and 17.4% (447 of 2561). Whereas liver fat is associated with predictors related to the metabolic syndrome, liver iron content is mainly associated with mean serum corpuscular hemoglobin. © RSNA, 2017 Online supplemental material is available for this article.

Iloprost, Prostaglandin E1, and Papaverine Relax Human Mesenteric Arteries With Similar Potency.

OBJECTIVE: Nonocclusive mesenteric ischemia (NOMI) is accompanied by mesenteric artery spasms that are at least in part due to endothelin system activation. Acute treatment includes intra-arterial infusion of vasodilators such as iloprost, prostaglandin E1 (PGE1), and papaverine. Their effectiveness is not well characterized in human mesenteric arteries. We directly compared their potency to relax isolated human mesenteric arteries. To explore the potential of Rock inhibition to treat mesenteric artery spasms, we tested if endothelin-1 (ET-1)-induced mesenteric artery constrictions depend on rho kinase (Rock). METHODS: Mesenteric artery segments were obtained from patients who underwent elective abdominal surgery. Vasodilator concentration-response curves were recorded from ET-1-preconstricted vessels by small vessel myography. Rock expression was investigated by Western blot and the potency of Rock inhibition to blunt ET-1-induced mesenteric artery constriction was tested. RESULTS: Iloprost, PGE1, and papaverine similarly reduced vascular tone to 20% to 30% of ET-1-induced wall tension. In human mesenteric arteries, logEC50 was significantly less for iloprost than for PGE1 or papaverine. Respective logEC50 values were -7.72 ±â€Š0.08 mol/L, -6.58 ±â€Š0.17 mol/L, and -6.73 ±â€Š0.19 mol/L in 150 µm to 300 µm lumen diameter arteries. These vessels were also more sensitive to iloprost than 500 µm to 1,000 µm lumen diameter arteries (logEC50 -7.29 ±â€Š0.07 mol/L). Rock1 and Rock2 were expressed in human mesenteric arteries but Rock inhibition did not significantly affect ET-1-induced vasoconstrictions. CONCLUSIONS: Iloprost, PGE1, and papaverine have a similar potency to relax mesenteric arteries. Our data suggest that iloprost but not Rock inhibition may be particularly useful to treat ET-1-induced spasms of distal mesenteric arteries.

High levels of thyroid-stimulating hormone are associated with aortic wall thickness in the general population.

OBJECTIVES: Our aim was to investigate the association of thyroid function defined by serum concentrations of thyroid-stimulating hormone (TSH) with thoracic aortic wall thickness (AWT) as a marker of atherosclerotic processes. METHODS: We pooled data of 2,679 individuals from two independent population-based surveys of the Study of Health in Pomerania. Aortic diameter and AWT measurements were performed on a 1.5-T MRI scanner at the concentration of the right pulmonary artery displaying the ascending and the descending aorta. RESULTS: TSH, treated as continuous variable, was significantly associated with descending AWT (ß = 0.11; 95 % confidence interval (CI) 0.02-0.21), while the association with ascending AWT was not statistically significant (ß = 0.20; 95 % CI -0.01-0.21). High TSH (>3.29 mIU/L) was significantly associated with ascending (ß = 0.12; 95 % CI 0.02-0.23) but not with descending AWT (ß = 0.06; 95 % CI -0.04-0.16). There was no consistent association between TSH and aortic diameters. CONCLUSIONS: Our study demonstrated that AWT values increase with increasing serum TSH concentrations. Thus, a hypothyroid state may be indicative for aortic atherosclerosis. These results fit very well to the findings of previous studies pointing towards increased atherosclerotic risk in the hypothyroid state. KEY POINTS: • Serum TSH concentrations are positively associated with aortic wall thickness. • Serum TSH concentrations are not associated with the aortic diameters. • Serum 3,5-diiodothyronine concentrations may be positively associated with aortic wall thickness.

Thoracic and abdominal aortic diameters in a general population: MRI-based reference values and association with age and cardiovascular risk factors.

OBJECTIVES: To generate reference values for thoracic and abdominal aortic diameters determined by magnetic resonance imaging (MRI) and analyse their association with cardiovascular risk factors in the general population. METHODS: Data from participants (n = 1759) of the Study of Health in Pomerania were used for analysis in this study. MRI measurement of thoracic and abdominal aortic diameters was performed. Parameters for calculation of reference values according to age and sex analysis were provided. Multivariable linear regression models were used for determination of aortic diameter-related risk factors, including smoking, blood pressure (BP), high-density lipoprotein cholesterol (HDL-C). RESULTS: For the ascending aorta (ß = -0.049, p < 0.001), the aortic arch (ß = -0.061, p < 0.001) and the subphrenic aorta (ß = -0.018, p = 0.004), the body surface area (BSA)-adjusted diameters were lower in men. Multivariable-adjusted models revealed significant increases in BSA-adjusted diameters with age for all six aortic segments (p < 0.001). Consistent results for all segments were observed for the positive associations of diastolic BP (ß = 0.001; 0.004) and HDL (ß = 0.035; 0.087) with BSA-adjusted aortic diameters and for an inverse association of systolic BP (ß = -0.001). CONCLUSIONS: Some BSA-adjusted median aortic diameters are smaller in men than in women. All diameters increase with age, diastolic blood pressure and HDL-C and decrease as systolic BP increases. KEY POINTS: • Median aortic diameter increases with age and diastolic blood pressure. • Median aortic diameter is larger in men than in women. • Some BSA-adjusted median aortic diameters are smaller in men than in women.

Fully automatized renal parenchyma volumetry using a support vector machine based recognition system for subject-specific probability map generation in native MR volume data.

In epidemiological studies as well as in clinical practice the amount of produced medical image data strongly increased in the last decade. In this context organ segmentation in MR volume data gained increasing attention for medical applications. Especially in large-scale population-based studies organ volumetry is highly relevant requiring exact organ segmentation. Since manual segmentation is time-consuming and prone to reader variability, large-scale studies need automatized methods to perform organ segmentation. Fully automatic organ segmentation in native MR image data has proven to be a very challenging task. Imaging artifacts as well as inter- and intrasubject MR-intensity differences complicate the application of supervised learning strategies. Thus, we propose a modularized framework of a two-stepped probabilistic approach that generates subject-specific probability maps for renal parenchyma tissue, which are refined subsequently by using several, extended segmentation strategies. We present a three class-based support vector machine recognition system that incorporates Fourier descriptors as shape features to recognize and segment characteristic parenchyma parts. Probabilistic methods use the segmented characteristic parenchyma parts to generate high quality subject-specific parenchyma probability maps. Several refinement strategies including a final shape-based 3D level set segmentation technique are used in subsequent processing modules to segment renal parenchyma. Furthermore, our framework recognizes and excludes renal cysts from parenchymal volume, which is important to analyze renal functions. Volume errors and Dice coefficients show that our presented framework outperforms existing approaches.

Predictors of technical success and rate of complications of image-guided percutaneous transthoracic lung needle biopsy of pulmonary tumors.

PURPOSE: To investigate predictors of technical success and complications of computed tomography (CT)-guided percutaneous transthoracic needle biopsy of potentially malignant pulmonary tumors. MATERIAL AND METHODS: From 2008 to 2009, technical success and rate of complications of CT-guided percutaneous transthoracic lung needle biopsies of patients with suspicious pulmonary tumors were retrospectively evaluated. The influence on technical success and rate of complications was assessed for intervention-related predictors (lesion diameter, length of biopsy pathway, number of pleural transgressions, and needle size) and patient-related predictors (age, gender, reduced lung function). In addition, technical success and rate of complications were compared between different interventional radiologists. RESULTS: One hundred thirty-eight patients underwent biopsies by 15 interventional radiologists. The overall technical success rate was 84.1% and was significantly different between interventional radiologists (range 25%-100%; p<0.01). Intervention-related and patient-related predictors did not influence the technical success rate. The overall complication rate was 59.4% with 39.1% minor complications and 21.0% major complications. The rate of complications was influenced by lesion diameter and distance of biopsy pathway. Interventional radiologist-related rates of complications were not statistically different. CONCLUSIONS: Technical success of percutaneous, transthoracic lung needle biopsies of pulmonary tumors is probably dependent on the interventional radiologist. In addition, lesion diameter and length of biopsy pathway are predictors of the rate of complications.