Association between thyroid function and assessment of hepatic fat and iron contents by magnetic resonance imaging.

The associations of thyroid function parameters with non-alcoholic fatty liver disease (NAFLD) and hepatic iron overload are not entirely clear. We have cross-sectionally investigated these associations among 2734 participants of two population-based cross-sectional studies of the Study of Health in Pomerania. Serum levels of thyroid-stimulating hormone (TSH), free tri-iodothyronine (fT3), and free thyroxine (fT4) levels were measured. Liver fat content (by proton-density fat fraction) as well as hepatic iron content (by transverse relaxation rate; R2*) were assessed by quantitative MRI. Thyroid function parameters were associated with hepatic fat and iron contents by median and logistic regression models adjusted for confounding. There were no associations between serum TSH levels and liver fat content, NAFLD, or hepatic iron overload. Serum fT4 levels were inversely associated with liver fat content, NAFLD, hepatic iron contents, and hepatic iron overload. Serum fT3 levels as well as the fT3 to fT4 ratio were positively associated with hepatic fat, NAFLD, hepatic iron contents, but not with hepatic iron overload. Associations between fT3 levels and liver fat content were strongest in obese individuals, in which we also observed an inverse association between TSH levels and NAFLD. These findings might be the result of a higher conversion of fT4 to the biologically active form fT3. Our results suggest that a subclinical hyperthyroid state may be associated with NAFLD, particularly in obese individuals. Furthermore, thyroid hormone levels seem to be more strongly associated with increased liver fat content compared to hepatic iron content.

MRI-based static and functional assessment of complex hip deformities in comparison with CT: a validation study.

OBJECTIVE: This study aimed at investigating the agreement between predefined quantitative parameters of hip morphology derived from magnetic resonance imaging (MRI) and virtual range of motion (ROM) analysis using computed tomography (CT) as standard of reference. METHODS: Twenty patients (13 females, 7 males, 16-59 years) with hip deformities underwent MRI prior to surgery. Clockwise alpha angle, femoral head and neck diameter, collum caput diaphysis angle, femoral torsion, center-edge angles, acetabular coverage of the femoral head, sourcil angle, and acetabular anteversion were measured. Additionally, tern single and combined movements were simulated using a motion analysis program. The MRI findings were compared with the corresponding results obtained by CT. Correlation of MRI with CT was assessed using different statistical methods (intraclass correlation coefficient, Bland-Altmann plot, two one-sided t test), and linear regression analysis was performed. RESULTS: The results showed near-perfect intraclass correlation coefficients (ICCs) for anteversion (0.95), acetabular sector angles (0.98-0.99), sourcil angle (0.95), and acetabular coverage (anterior 0.96, posterior 0.99). Intermethod correlation for femoral parameters showed almost perfect agreement except for the alpha angle (0.73-0.97). No significant proportional bias was detected for traditional acetabular and femoral parameters. ROM analysis was performed for 370 movements in 37 hips. For 78.4% (290/370) of the movements analysed, neither CT nor MRI detected impingement across the physiological ROM. For 18.6% (69/370) of the movements, impingement was detected by both CT and MRI, while 2.2% (8/370) of the movements with impingement in CT showed no impingement in MRI, and 0.8% (3/370) of the movements with impingement in MRI had no corresponding result in CT. CONCLUSION: Finally, it was concluded that MRI-based assessment of hip morphology and virtual ROM analysis is feasible and can be performed with good intermethod agreement in comparison to the gold standard (CT). Therefore, MRI appears to be substantially equivalent to CT for use in virtual ROM analysis and so may reasonably be used in place of CT for this purpose.

The Clinical and Socio-Economic Relevance of Increased IPMN Detection Rates and Management Choices.

BACKGROUND: Increased usage of computed tomography and magnetic resonance imaging has led to a large increase in identified pancreatic cysts of up to 25% in population-based studies. The clinical and economic relevance of identifying so many cystic lesions has not been established. Compared to other organs such as liver or kidney, dysontogenetic pancreatic cysts are rare. Pancreatic cysts comprise a variety of benign, premalignant or malignant lesions; however, precise diagnosis before resection has an accuracy of only 80%. The focus of recent research was the malignant potential of intraductal papillary mucinous neoplasms (IPMN) with the aim of establishing clinical pathways addressing risk of malignancy, age and comorbidity, treatment-related morbidity and mortality as well as cost-effectiveness of treatment and surveillance. The focus of this review is to analyze the clinical and socio-economic relevance as well as the cost-benefit relation for IPMNs. METHODS: For analysis, the following MESH terms were used to identify original articles, reviews, and guidelines in PubMed: ('intraductal papillary mucinous neoplasm' OR 'pancreatic cysts') and (incidence OR relevance OR socio-economic OR economic OR cost-effectiveness OR cost-benefit). The retrieved publications were reviewed with a focus on clinical and socio-economic relevance in relation to the increasing incidence of IPMN. RESULTS: Addressing the increasing prevalence of pancreatic cystic lesions, recent consensus guidelines suggested criteria for risk stratification according to 'worrisome features' and 'high-risk stigmata'. Recent prospective cohort studies evaluated whether these can be applied in clinical practice. Evaluation of three different clinical scenarios with regard to costs and quality-adjusted life years suggested a better effectiveness of surveillance after initial risk stratification by endoscopic ultrasound-guided fine-needle aspiration with cyst fluid analysis compared with immediate resection or follow-up without further intervention. Of interest, the 'immediate surgery' strategy was lowest for cost-effectiveness. CONCLUSIONS: The increasing incidence of identified pancreatic cysts requires an improved strategy for non-invasive risk stratification based on advanced imaging strategies. In light of a malignancy risk of 2% for branch-duct IPMN, the socio-economic necessity of a balance between surveillance and resection has to be agreed on.

New technique for prostate volume assessment.

PURPOSE: The prostate-specific antigen density (PSAD) helps distinguish between benign prostatic hyperplasia (BPH) and prostate cancer. Accurate prostate volume (PV) assessment is necessary for PSAD calculation and both BPH diagnosis and treatment response monitoring; therefore, accurate PV measurement is increasingly becoming an essential step in the urology. METHODS: Magnetic resonance imaging was used for PV estimation. A new technique based on single-class support-vector machines (S SVM) for accurate PV estimation was realized. Three estimation methods were compared; method 1: planimetry (reference), method 2: S SVM based, and method 3: prolate ellipsoid. RESULTS: Method 1 and method 2 depict a strong correlation (Spearman's rank correlation coefficient ρ = 0.965, p > 0.001). The interrater reliability for method 1 and method 2 readings as expressed by the intraclass correlation coefficient (ICC) was 0.975 (p > 0.001). Comparison between method 3 and the two other methods shows ρ = 0.873 (p > 0.001), and ρ = 0.795 (p > 0.001), respectively. ICC was 0.54 and 0.505, respectively. The mean difference between method 1 and method 2 was -0.05 ml. The limits of agreement with the 95 % confidence interval were -3.8 to 3.7 ml. Comparing method 3 and the two other methods shows a worse agreement with mean difference of 8.6 ml (95 % confidence interval of 1.0-16.2 ml) and 8.6 ml (95 % confidence interval of -0.7 to 18.0 ml), respectively. CONCLUSIONS: The prostate volumes obtained by our technique agreed excellently with the planimetry (reference) method. This new technique would be clinically useful for urologists in prostate volumetric analysis.

Secretin-stimulated MRCP in volunteers: assessment of safety, duct visualization, and pancreatic exocrine function.

OBJECTIVE: The objective of our study was to investigate secretin-stimulated MRCP in terms of the safety of secretin, improvement of duct visualization, and assessment of pancreatic exocrine function. MATERIALS AND METHODS: Eight hundred sixteen volunteers (370 women and 446 men; mean age, 49.7 ± 13.1 [SD] years) underwent 3D MRCP before and after secretin stimulation (1 U/kg of body weight) at 1.5 T. For the first 2 hours after secretin injection, subjects were evaluated for adverse reactions. Improvement of duct visualization after secretin stimulation was subjectively evaluated by two readers and was quantified by duct diameter measurements. Pancreatic exocrine function was evaluated subjectively by two readers according to the duodenal filling and was quantified using calibrated volumetric measurements of total excreted volume and pancreatic flow output. RESULTS: Two subjects (0.2%) showed flushing (minor adverse reaction). Duct visualization after secretin injection was improved for reader 1 in 468 (57.4%) and for reader 2 in 478 (58.6%) subjects, was unchanged for reader 1 in 324 (39.7%) and for reader 2 in 315 (38.6%) subjects, and was worse for reader 1 in 24 (2.9%) and reader 2 in 23 (2.8%) subjects (interrater agreement, κ = 0.925). Main pancreatic duct diameters increased significantly after secretin stimulation: pancreatic head, 10.5% (mean); body, 12.5%; and tail, 7.7%. Pancreatic exocrine function evaluated according to assessment of duodenal filling was as follows: grade 0 (restricted function) in 0.7% of subjects by both readers, grade 1 (reduced function) in 4.8% of subjects by reader 1 and 4.5% of subjects by reader 2, grade 2 (low-grade reduced function) in 31.1% of subjects by reader 1 and 26.5% of subjects by reader 2, and grade 3 (physiologic function) in 63.4% of subjects by reader 1 and 68.3% of subjects by reader 2 (interrater agreement, κ = 0.838). The mean total excreted volume was 111.8 ± 49.8 (SD) mL, and the mean pancreatic flow output was 9.6 ± 4.2 mL/min. CONCLUSION: Secretin-stimulated MRCP moderately improves main pancreatic duct visualization and allows noninvasive quantification of pancreatic exocrine function with a negligible risk of side effects.

Proton-density fat fraction and simultaneous R2* estimation as an MRI tool for assessment of osteoporosis.

OBJECTIVE: To investigate multi-echo chemical shift-encoded MRI-based mapping of proton density fat fraction (PDFF) and fat-corrected R2* in bone marrow as biomarkers for osteoporosis assessment. METHODS: Fifty-one patients (28 female; mean age 69.7 ± 9.0 years) underwent dual energy X-ray absorptiometry (DXA). On the basis of the t score, 173 valid vertebrae bodies were divided into three groups (healthy, osteopenic and osteoporotic). Three echo chemical shift-encoded MRI sequences were acquired at 3 T. PDFF and R2* with correction for multiple-peak fat (R2*MP) were measured for each vertebral body. Kruskal-Wallis test and post hoc analysis were performed to evaluate differences between groups. Further, the area under the curve (AUC) for each technique was calculated using logistic regression analysis. RESULTS: On the basis of DXA, 92 samples were normal (53 %), 47 osteopenic (27 %) and 34 osteoporotic (20 %). PDFF was increased in osteoporosis compared with healthy (P = 0.007). R2*MP showed significant differences between normal and osteopenia (P = 0.004), and between normal and osteoporosis (P < 0.001). AUC to differentiate between normal and osteoporosis was 0.698 for R2*MP, 0.656 for PDFF and 0.74 for both combined. CONCLUSION: PDFF and R2*MP are moderate biomarkers for osteoporosis. PDFF and R2*MP combination might improve the prediction in differentiating healthy subjects from those with osteoporosis.