Prediction of abdominal CT body composition parameters by thoracic measurements as a new approach to detect sarcopenia in a COVID-19 cohort.

As most COVID-19 patients only receive thoracic CT scans, but body composition, which is relevant to detect sarcopenia, is determined in abdominal scans, this study aimed to investigate the relationship between thoracic and abdominal CT body composition parameters in a cohort of COVID-19 patients. This retrospective study included n = 46 SARS-CoV-2-positive patients who received CT scans of the thorax and abdomen due to severe disease progression. The subcutaneous fat area (SF), the skeletal muscle area (SMA), and the muscle radiodensity attenuation (MRA) were measured at the level of the twelfth thoracic (T12) and the third lumbar (L3) vertebra. Necessity of invasive mechanical ventilation (IMV), length of stay, or time to death (TTD) were noted. For statistics correlation, multivariable linear, logistic, and Cox regression analyses were employed. Correlation was excellent for the SF (r = 0.96) between T12 and L3, and good for the respective SMA (r = 0.80) and MRA (r = 0.82) values. With adjustment (adj.) for sex, age, and body-mass-index the variability of SF (adj. r2 = 0.93; adj. mean difference = 1.24 [95% confidence interval (95% CI) 1.02-1.45]), of the SMA (adj. r2 = 0.76; 2.59 [95% CI 1.92-3.26]), and of the MRA (adj. r2 = 0.67; 0.67 [95% CI 0.45-0.88]) at L3 was well explained by the respective values at T12. There was no relevant influence of the SF, MRA, or SMA on the clinical outcome. If only thoracic CT scans are available, CT body composition values at T12 can be used to predict abdominal fat and muscle parameters, by which sarcopenia and obesity can be assessed.

Skeletal muscle fat quantification by dual-energy computed tomography in comparison with 3T MR imaging.

OBJECTIVES: To quantify the proportion of fat within the skeletal muscle as a measure of muscle quality using dual-energy CT (DECT) and to validate this methodology with MRI. METHODS: Twenty-one patients with abdominal contrast-enhanced DECT scans (100 kV/Sn 150 kV) underwent abdominal 3-T MRI. The fat fraction (DECT-FF), determined by material decomposition, and HU values on virtual non-contrast-enhanced (VNC) DECT images were measured in 126 regions of interest (≥ 6 cm2) within the posterior paraspinal muscle. For validation, the MR-based fat fraction (MR-FF) was assessed by chemical shift relaxometry. Patients were categorized into groups of high or low skeletal muscle mean radiation attenuation (SMRA) and classified as either sarcopenic or non-sarcopenic, according to the skeletal muscle index (SMI) and cut-off values from non-contrast-enhanced single-energy CT. Spearman's and intraclass correlation, Bland-Altman analysis, and mixed linear models were employed. RESULTS: The correlation was excellent between DECT-FF and MR-FF (r = 0.91), DECT VNC HU and MR-FF (r = - 0.90), and DECT-FF and DECT VNC HU (r = - 0.98). Intraclass correlation between DECT-FF and MR-FF was good (r = 0.83 [95% CI 0.71-0.90]), with a mean difference of - 0.15% (SD 3.32 [95% CI 6.35 to - 6.66]). Categorization using the SMRA yielded an eightfold difference in DECT VNC HU values between both groups (5 HU [95% CI 23-11], 42 HU [95% CI 33-56], p = 0.05). No significant relationship between DECT-FF and SMI-based classifications was observed. CONCLUSIONS: Fat quantification within the skeletal muscle using DECT is both feasible and reliable. DECT muscle analysis offers a new approach to determine muscle quality, which is important for the diagnosis and therapeutic monitoring of sarcopenia, as a comorbidity associated with poor clinical outcome. KEY POINTS: • Dual-energy CT (DECT) material decomposition and virtual non-contrast-enhanced DECT HU values assess muscle fat reliably. • Virtual non-contrast-enhanced dual-energy CT HU values allow to differentiate between high and low native skeletal muscle mean radiation attenuation in contrast-enhanced DECT scans. • Measuring muscle fat by dual-energy computed tomography is a new approach for the determination of muscle quality, an important parameter for the diagnostic confirmation of sarcopenia as a comorbidity associated with poor clinical outcome.

Diffusion tensor imaging combined with T2 mapping to quantify changes in the skeletal muscle associated with training and endurance exercise in competitive triathletes.

OBJECTIVES: Diffusion tensor magnetic resonance imaging (DTI) and T2 mapping enable the detection of exercise-induced changes in the skeletal muscle microenvironment. This study prospectively quantified DTI metrics and T2 relaxation times of thigh muscles in competitive triathletes at rest and following a triathlon race in comparison with sedentary controls. METHODS: Twenty-two triathletes (males N = 16, females N = 6) and twenty-three controls (males N = 16, females N = 7) underwent magnetic resonance imaging (MRI) on a 3 T system at baseline (time point 1; 72 h at rest). Twelve triathletes (males N = 8, females N = 4) underwent a second scan (time point 2; 3 h of completing a triathlon race). The tensor eigenvalues (λ1, λ2, λ3), mean diffusivity (MD), fractional anisotropy (FA), and T2 times were compared between controls and triathletes at time point 1 and triathletes at time points 1 and 2 using independent and paired t tests. RESULTS: In comparison with the controls at time point 1, the T2 times of rectus femoris (RF, p < 0.02), adductor magnus (AM, p = 0.02), biceps femoris (BF, p < 0.001), semitendinosus (ST, p = 0.005), and semimembranosus (SM, p = 0.003) muscles were significantly increased in triathletes. At time point 2 in triathletes, the average tensor metrics (MD, λ3/ λ1) of BF, ST, and SM muscles increased (p < 0.05) and FA values in ST and SM muscles decreased (p < 0.03). T2 times were not significantly changed between both time points in triathletes. CONCLUSION: Our results indicate that this multiparametric MRI protocol allows detection and quantification of changes in the skeletal muscle microenvironment caused by endurance training and acute strenuous exercise. KEY POINTS: • Endurance training results in changes to the skeletal microstructure, which can be quantified using MRI-based diffusion tensor imaging. • The combined application of MRI diffusion tensor imaging and T2 mapping allows the differentiation of microstructural changes caused by active exercise or endurance training. • Environmental adaptations of the skeletal muscle caused by physical training are influenced by gender.

Fetal dynamic phase-contrast MR angiography using ultrasound gating and comparison with Doppler ultrasound measurements.

OBJECTIVES: To investigate the feasibility of fetal phase-contrast (PC)-MR angiography of the descending aorta (AoD) using an MR-compatible Doppler ultrasound sensor (DUS) for fetal cardiac gating and to compare velocimetry with Doppler ultrasound measurements. METHODS: In this prospective study, 2D PC-MR angiography was performed in 12 human fetuses (mean gestational age 32.8 weeks) using an MR-compatible DUS for gating of the fetal heart at 1.5 T. Peak flow velocities in the fetal AoD were compared with Doppler ultrasound measurements performed on the same day. Reproducibility of PC-MR measurements was tested by repeated PC-MR in five fetuses. RESULTS: Dynamic PC-MR angiography in the AoD was successfully performed in all fetuses using the DUS, with an average fetal heart rate of 140 bpm (range 129-163). Time-velocity curves revealed typical arterial blood flow patterns. PC-MR mean flow velocity and mean flux were 21.2 cm/s (range 8.6-36.8) and 8.4 ml/s (range 3.2-14.6), respectively. A positive association between PC-MR mean flux and stroke volume with gestational age was obtained (r = 0.66, p = 0.02 and r = 0.63, p = 0.03). PC-MR and Doppler ultrasound peak velocities revealed a highly significant correlation (r = 0.8, p < 0.002). Peak velocities were lower for PC-MR with 69.1 cm/s (range 39-125) compared with 96.7 cm/s (range 60-142) for Doppler ultrasound (p < 0.001). Reproducibility of PC-MR was high (p > 0.05). CONCLUSION: The MR-compatible DUS for fetal cardiac gating allows for PC-MR angiography in the fetal AoD. Comparison with Doppler ultrasound revealed a highly significant correlation of peak velocities with underestimation of PC-MR velocities. This new technique for direct fetal cardiac gating indicates the potential of PC-MR angiography for assessing fetal hemodynamics. KEY POINTS: • The developed MR-compatible Doppler ultrasound sensor allows direct fetal cardiac gating and can be used for prenatal dynamic cardiovascular MRI. • The MR-compatible Doppler ultrasound sensor was successfully applied to perform intrauterine phase-contrast MR angiography of the fetal aorta, which revealed a highly significant correlation with Doppler ultrasound measurements. • As fetal flow hemodynamics is an important parameter in the diagnosis and management of fetal pathologies, fetal phase-contrast MR angiography may offer an alternative imaging method in addition to Doppler ultrasound and develop as a second line tool in the evaluation of fetal flow hemodynamics.

Diffusion Tensor Imaging of Dystrophic Skeletal Muscle : Comparison of Two Segmentation Methods Adapted to Chemical-shift-encoded Water-fat MRI.

PURPOSE: To compare the influence of two different regions of interest (ROIs) on diffusion tensor metrics in dystrophic thigh muscles using a custom-made (whole muscle) ROI including and a selective ROI excluding areas of fatty replacement. METHODS: Diffusion tensor imaging (DTI) and chemical-shift-encoded water-fat magnetic resonance imaging (MRI) of the thigh was conducted on a 3-Tesla system in 15 cases with muscular dystrophy and controls. The ROIs were chosen according to patterns of fatty replacement on co-registered axial DTI and gradient echo sequence (GRE) images. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), fiber track length (FTL), and muscle fat fractions (MFF) were compared between both ROI segmentations. These comparisons, muscle-specific correlation coefficients, and the influence of ROI localization on tensor metrics were derived based on linear mixed effects regression models. RESULTS: In the cases a high correlation was observed for ADC and FA with MFF using a custom ROI. The correlation was weaker but still significant with a selective ROI method. Using the custom ROI, FTL correlated significantly with MFF in 3 out of 4 muscles (r ≤ -0.51). A correlation was not found for the selective ROI method. Interaction analysis revealed that the association of ADC and FA with MFF was not significantly influenced by the ROI localization. For FTL the ROI localization significantly reduced the negative association with MFF. CONCLUSION: The DTI metrics and FTL of custom ROI segmentation are significantly influenced by MFF. Contrary to ADC and FA, the effect of MFF on FTL is significantly reduced when applying selective ROI segmentation, which could therefore be a better option for MR tractography.

Prospective comparison of diffusion-weighted MRI and dynamic Gd-EOB-DTPA-enhanced MRI for detection and staging of hepatic fibrosis in primary sclerosing cholangitis.

PURPOSE: To assess the diagnostic value of multiparametric magnetic resonance imaging (MRI) including dynamic Gd-EOB-DTPA-enhanced (DCE) and diffusion-weighted (DW) imaging for diagnosis and staging of hepatic fibrosis in primary sclerosing cholangitis (PSC) using transient elastography as a standard reference. MATERIAL AND METHODS: Multiparametric MRI was prospectively performed on a 3.0-Tesla scanner in 47 patients (age 43.9±14.3 years). Transient elastography derived liver stiffness measurements (LSM), DCE-MRI derived parameters (hepatocellular uptake rate (Ki), arterial (Fa), portal venous (Fv) and total (Ft) blood flow, mean transit time (MTT), and extracellular volume (Ve)) and the apparent diffusion coefficient (ADC) were calculated. Correlation and univariate analysis of variance with post hoc pairwise comparison were applied to test for differences between LSM derived fibrosis stages (F0/F1, F2/3, F4). ROC curve analysis was used as a performance measure. RESULTS: Both ADC and Ki correlated significantly with LSM (r= -0.614; p<0.001 and r= -0.368; p=0.01). The ADC significantly discriminated fibrosis stages F0/1 from F2/3 and F4 (p<0.001). Discrimination of F0/1 from F2/3 and F4 reached a sensitivity/specificity of 0.917/0.821 and 0.8/0.929, respectively. Despite significant inter-subject effect for classification of fibrosis stages, post hoc pairwise comparison was not significant for Ki (p>0.096 for F0/1 from F2/3 and F4). LSM, ADC and Ki were significantly associated with serum-based liver functional tests, disease duration and spleen volume. CONCLUSION: DW-MRI provides a higher diagnostic performance for detection of hepatic fibrosis and cirrhosis in PSC patients in comparison to Gd-EOB-DTPA-enhanced DCE-MRI. KEY POINTS: • Both ADC and hepatocellular uptake rate (Ki) correlate significantly with liver stiffness (r= -0.614; p<0.001 and r= -0.368; p=0.01). • The DCE-imaging derived quantitative parameter hepatocellular uptake rate (Ki) fails to discriminate pairwise intergroup differences of hepatic fibrosis (p>0.09). • DWI is preferable to DCE-imaging for discrimination of fibrosis stages F0/1 to F2/3 (p<0.001) and F4 (p<0.001).

Dynamic fetal cardiac magnetic resonance imaging in four-chamber view using Doppler ultrasound gating in normal fetal heart and in congenital heart disease: comparison with fetal echocardiography.

OBJECTIVES: To investigate the diagnostic performance of dynamic fetal cardiac magnetic resonance imaging (MRI), using a MR-compatible Doppler ultrasound (DUS) device for fetal cardiac gating, in differentiating fetuses with congenital heart disease from those with a normal heart, and to compare the technique with fetal echocardiography. METHODS: This was a prospective study of eight fetuses with a normal heart and four with congenital heart disease (CHD), at a median of 34 (range, 28-36) weeks' gestation. Dynamic fetal cardiac MRI was performed using a DUS device for direct cardiac gating. The four-chamber view was evaluated according to qualitative findings. Measurements of the length of the left and right ventricles, diameter of the tricuspid and mitral valves, myocardial wall thickness, transverse cardiac diameter and left ventricular planimetry were performed. Fetal echocardiography and postnatal diagnoses were considered the reference standards. RESULTS: Direct cardiac gating allowed continuous triggering of the fetal heart, showing high temporal and spatial resolution. Both fetal cardiac MRI and echocardiography in the four-chamber view detected pathological findings in three of the 12 fetuses. Qualitative evaluation revealed overall consistency between echocardiography and MRI. On both echocardiography and MRI, quantitative measurements revealed significant differences between fetuses with a normal heart and those with CHD with respect to the length of the right (P < 0.01 for both) and left (P < 0.01 for both) ventricles and transverse cardiac diameter (P < 0.05 and P < 0.01, respectively). Tricuspid valve diameter on cardiac MRI was found to be significantly different in healthy fetuses from in those with CHD (P < 0.05). CONCLUSIONS: For the first time, this study has shown that dynamic fetal cardiac MRI in the four-chamber view, using external cardiac gating, allows evaluation of cardiac anatomy and diagnosis of congenital heart disease in agreement with fetal echocardiography. Dynamic fetal cardiac MRI may be useful as a second-line investigation if conditions for fetal echocardiography are unfavorable. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Follow-up magnetic resonance imaging/3D-magnetic resonance cholangiopancreatography in patients with primary sclerosing cholangitis: challenging for experts to interpret.

BACKGROUND: In patients with primary sclerosing cholangitis follow-up magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) is performed by many centres, particularly for the early detection of biliary malignancies and strictures. Clinically meaningful MRI-based definitions of primary sclerosing cholangitis related complications are, however, lacking. AIM: To investigate how primary sclerosing cholangitis experts interpret follow-up MRI/MRCP with a focus on conclusions that may impact clinical decision-making in primary sclerosing cholangitis. METHODS: Within the International Primary Sclerosing Cholangitis Study Group, an online survey on 16 real-life primary sclerosing cholangitis cases including clinical and biochemical information as well as a T2-weighted liver MRI/3D-MRCP was conducted. The interpretation of images and subsequent recommendations were assessed using a multiple-choice questionnaire. An inter-rater reliability calculation (Fleiss' kappa) was performed and factors potentially affecting the interpretation of magnetic resonance images were analysed using generalised linear mixed-effect models. RESULTS: Forty-four members/associates of the International Primary Sclerosing Cholangitis Study Group (median experience in the care of primary sclerosing cholangitis patients: 14 years) completed the survey. The MRI interpretation significantly varied among the participants. The lowest agreement was found with respect to the indication to perform subsequent endoscopic retrograde cholangiopancreatography (ERCP; Κ = 0.12, 95%CI 0.11-0.14). Elevated total bilirubin was the variable with the strongest effect on the rate of suspected dominant strictures, cholangiocarcinoma or ERCP recommendations. Liver cirrhosis did not prevent participants from recommending ERCP. Overall, the survey participants' recommendations contrasted the real-life management and outcome. CONCLUSIONS: In primary sclerosing cholangitis, the interpretation of follow-up MRI/3D-MRCP significantly varies even among experts and seems to be primarily affected by bilirubin levels. Generally accepted MRI-based definitions of primary sclerosing cholangitis-related complications are urgently needed.

Adaptive changes in pancreas post Roux-en-Y gastric bypass induced weight loss.

BACKGROUND: Obesity has been shown to trigger adaptive increases in pancreas parenchymal and fat volume. Consecutively, pancreatic steatosis may lead to beta-cell dysfunction. However, it is not known whether the pancreatic tissue components decrease with weight loss and pancreatic steatosis is reversible following Roux-en-Y gastric bypass (RYGB). Therefore, the objective of the study was to investigate the effects of RYGB-induced weight loss on pancreatic volume and glucose homeostasis. METHODS: Eleven patients were recruited in the Obesity Centre of the University Medical Centre Hamburg-Eppendorf. Before and 6 months after RYGB, total GLP-1 levels were measured during oral glucose tolerance test. To assess changes in visceral adipose tissue and pancreatic volume, MRI was performed. Measures of glucose homeostasis and insulin indices were assessed. Fractional beta-cell area was estimated by correlation with the C-peptide-to-glucose ratio; beta-cell mass was calculated by the product of beta-cell area and pancreas parenchymal weight. RESULTS: Pancreas volume decreased from 83.8 (75.7-92.0) to 70.5 (58.8-82.3) cm3 (mean [95% CI], P = .001). The decrease in total volume was associated with a significant decrease in fat volume. Fasting insulin and C-peptide were lower post RYGB. HOMA-IR levels decreased, whereas insulin sensitivity increased (P = .03). This was consistent with a reduction in the estimated beta-cell area and mass. CONCLUSIONS: Following RYGB, pancreatic volume and steatosis adaptively decreased to "normal" levels with accompanying improvement in glucose homeostasis. Moreover, obesity-driven beta-cell expansion seems to be reversible; however, future studies must define a method to more accurately estimate functional beta-cell mass to increase our understanding of glucose homeostasis after RYGB.

Gadolinium-based relative contrast enhancement in primary sclerosing cholangitis: additional benefit for clinicians?

AIM: To evaluate the benefit of extracellular gadolinium-based contrast agent (GBCA) enhanced magnetic resonance imaging (MRI) in addition to conventional non-enhanced T2-weighted imaging (WI) for quantification of inflammatory or fibrotic alterations in the liver parenchyma of patients with primary sclerosing cholangitis (PSC). MATERIAL AND METHODS: MRI (3 T) examinations were reviewed retrospectively by two radiologists in 27 PSC patients (age 42.9±15.6 years), and 19 controls. Regions of interest (ROIs) were drawn onto T2 hyperintense and T2 isointense areas and copied to section position matched non-enhanced and delayed-phase contrast-enhanced T1WI. Signal intensities (SI) obtained from ROIs of the multiphase T1WI were used to calculate relative liver enhancement (RLE). The interobserver agreement of RLE and quantified T2 signal was calculated using Bland-Altman analysis. RLE assessed for both T2 hyperintense (RLEhyper) and T2 isointense (RLEiso) areas were compared in patients and controls (RLEhealthy). RESULTS: The interobserver agreement of RLE in affected hyperintense areas (bias -0.77, limits of agreement -51.7 to 50.1) was superior to the quantification of T2 signal only in these areas (bias -3.35, limits of agreement -162.4 to 155.7). The RLEhyper (86.2±9.7%) was higher than the RLEiso (59.8±6.2%, p=0.03) and the RLEhealthy (53.2±2.7%, p=0.002). The mean RLEiso was not significantly different from the RLEhealthy (p=0.3). CONCLUSION: The extracellular gadolinium-based RLE of T2 hyperintense areas could be a useful add-on for routine follow up MRI in the detection of early inflammatory changes, possibly preceding formation of fibrotic scarring in PSC patients, if validated in larger cohorts.

Doppler ultrasound triggering for cardiac MRI at 7T.

PURPOSE: A prerequisite for cardiac MR (CMR) imaging is adequate synchronization of image acquisition with the cardiac cycle. Electrocardiogram triggering may be hampered by electromagnetic interferences at high field strength. The purpose of this work is to evaluate the feasibility of Doppler ultrasound triggering for CMR image synchronization at 7T ultra-high-field MRI. METHODS: A custom-built Doppler ultrasound (DUS) trigger device was developed. Magnetic resonance compatibility was evaluated using E- and H-field probes and flip angle maps prior to the study. Cardiac MR was performed at 7T in 13 healthy subjects using DUS and pulse oximetry for triggering. For validation of the trigger signal, the electrocardiogram, pulse, and DUS signals were compared outside of the MR room. Breath-hold cine fast low-angle-shot sequences were acquired in short-axis and four-chamber view. Image quality was assessed by two senior radiologists and by measurement of endocardial blurring. RESULTS: The maximal change in E- and H-field distributions with and without transducer was 5%. No interferences were observed between DUS and MRI in the B1 maps and during CMR imaging. Validation of the DUS trigger signal resulted in a high correlation to the electrocardiographic signal of r = 0.99. Analysis of image and trigger quality revealed no significant differences. CONCLUSION: Doppler ultrasound was applied as a new trigger method in CMR at 7T. The transmission line and transducer were locally approved as 7T MR conditional, and were successfully tested for image synchronization at 7T. In the future, this method needs to be evaluated in a larger patient population. Magn Reson Med 80:239-247, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Lateralized Odontoid in Plain Film Radiography: Sign of Fractures? A Comparison Study with MDCT.

PURPOSE: To evaluate X-ray standards for the detection of odontoid fractures. SUMMARY OF BACKGROUND DATA: Cervical spine fractures are a common finding in emergency medicine, accounting for 1-3% of injuries. Involvement of the C1/C2 complex is found in 25% of cases, affecting the odontoid peg in 55-80%. Regarding the consequences of missed fractures, radiographic techniques built the groundwork for further treatment procedures. As standardized X-ray measurements have not been established, the incidence of unrecognized cervical spine fracture is expected to be up to 20%. The establishment of X-ray-based guidelines is also limited by the presumed low specificity and sensitivity of distance measurements caused by rotational distortion which leads to a rising popularity of CT. MATERIALS AND METHODS: 79 (age 60 ± 26 yrs) patients with lateralization of the odontoid process on conventional plain film radiography (anteroposterior, lateral, and open mouth odontoid process view projection) were examined. The distance between the odontoid process and lateral mass of C1, angles of vertical odontoid line and basis of C2 were measured in the ap view. In the lateral view, dorsal alignment and atlantodental distance were assessed. MDCT examinations were used as a reference. Discriminatory power test was applied to assess significance. RESULTS: 8/79 (10.1%) odontoid process fractures were found. Diagnosis was achieved on conventional radiographs in 6 patients. Neither distance and angle measurements between odontoid and C1 nor the dorsal alignment of the vertebral bodies differed significantly between healthy and affected patients. CONCLUSION: Decentralization of the odontoid process is not necessarily an indirect sign for its fracture. In patients with suspected injury of the odontoid process, an MDCT scan might be the method of choice to rule out a fracture. KEY POINTS: Due to the wide physiological variety of odontoid process position, even a detailed metric analysis of cervical alignment and odontoid process angulation in X-ray scans is not able to facilitate the diagnosis of odontoid process fractures. In the case of cervical spine trauma, which necessitate medical imaging, a primary MDCT scan should be the method of choice.

Comparison of Cine-MRI and Transthoracic Echocardiography for the Assessment of Aortic Root Diameters in Patients with Suspected Marfan Syndrome.

PURPOSE: Patients with Marfan syndrome require repeated imaging for monitoring of aortic root aneurysms. Therefore, we evaluated the agreement and reproducibility of cine-MRI and echocardiography measurements of the sinuses of Valsalva in patients with suspected Marfan syndrome. MATERIALS AND METHODS: 51 consecutive patients with suspected Marfan syndrome were prospectively examined using cine-MRI and echocardiography. Two readers independently measured aortic root diameters at the level of the sinuses of Valsalva in both cine-MRI and echocardiography. Statistics included intraclass correlation coefficient, Pearson correlation coefficient, Bland-Altman analysis, and two-sided t-test. RESULTS: In 38 of the 51 individuals (74.5 %), the diagnosis of Marfan syndrome was established according to the criteria of the Ghent-2 nosology. Cine-MRI measurements of the sinuses of Valsalva revealed a strong correlation with echocardiography (r = 0.929), but a statistically significant bias of -1.0  mm (p < 0.001). The mean absolute diameter for sinuses of Valsalva obtained by cine-MRI was 32.3  ±  5.8 mm as compared to 33.4  ±  5.4 mm obtained by echocardiography. Interobserver agreement of measurements of the sinuses of Valsalva was higher for cine-MRI than for echocardiography (p = 0.029). CONCLUSION: Despite small, but statistically significant differences in terms of agreement and reproducibility, cine-MRI and echocardiographic measurements of aortic root diameters provide comparable results without a significant clinical difference. Therefore both techniques may be used for monitoring of the aortic root in patients with Marfan syndrome.

Isolated syndesmotic injury in acute ankle trauma: comparison of plain film radiography with 3T MRI.

OBJECTIVES: To determine cut-off values and the accuracy of plain film measurements for the detection of isolated syndesmotic injury after acute ankle trauma and to investigate MRI findings of concomitant ankle injury. METHODS: Eighty-four consecutive patients with absent fracture in plain film radiographs were prospectively evaluated for isolated syndesmotic injury after acute ankle trauma. The tibiofibular clear space (TFCS), the tibiofibular overlap (TFO), and the medial clear space (MCS) were independently assessed in plain radiographs by two readers. MRI performed at 3T within 24h served as the reference standard. MRI was evaluated for syndesmotic injury, using a four-scale grading system (0=normal syndesmosis, 1a=periligamentous edema, 1b=intraligamentous edema, 2=partial rupture, 3=complete rupture), and for concomitant ankle injury. Inter-observer variability for x-ray measurements was assessed using Bland-Altman diagrams. ROC analyses were performed to determine cut-off values and sensitivity and specificity for TFCS, TFO, and MCS. RESULTS: Eleven of 84 patients (13.1%) revealed syndesmotic injury (Grade 2 or 3) according to MRI. Between patients with and without syndesmotic injury significantly different measurements were obtained for TFCS (p=0.003) and MCS (p=0.04). ROC derived cut-off values were 5.3mm for TFCS, 2.8mm for TFO, and 2.8mm for MCS. Sensitivity and specificity was 82% and 75% for TFCS, 36% and 78% for TFO, and 73% and 59% for MCS. The bias and limits of agreement were -0.04 mm and [-1.54; 1.53] for TFCS, 0.8mm and [-2.5; 2.5] for TFO, and 0.05 mm and [-1.42; 1.43] for MCS. Patients with syndesmotic injury had a 5-fold increased risk of concomitant ankle injury (p=0.07). CONCLUSIONS: The determined cut-off values aid in the evaluation of syndesmotic integrity in patients with absent fracture in plain radiographs. In case of increased distances MRI is recommended to assess severity of SI and to reveal associated ankle injuries.

Imaging of appendicitis in adults.

UNLABELLED: Three imaging modalities are available for the diagnosis of acute appendicitis: ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Transabdominal ultrasound should be the first-line imaging test. Abdominal CT is superior to US and is required immediately in patients with atypical clinical presentation of appendicitis and suspected perforation. However, low-dose unenhanced CT is equal to standard-dose CT with intravenous contrast agents in the detection of five signs of acute appendicitis (thickened appendiceal wall more than 2 mm, cross-sectional diameter greater than 6 mm, periappendicitis, abscess, and appendicolith). MRI is necessary in pregnant women and young adults. This review illustrates the principles of state-of-the-art imaging techniques and their clinical relevance. KEY POINTS: • US is the basic diagnostic method in case of suspected appendicitis.• CT is necessary in patients with atypical presentation of appendicitis.• MRI should be the first-line imaging test in pregnant women.

[Iron quantification in iron overload disease using MRI]. / Eisenquantifizierung mittels MRT bei Eisenüberladung.

Iron as an essential nutrient is involved in multiple metabolic activities. The importance of a sufficient iron supply is stressed by the fact that, according to WHO data, about 30 % of the global population suffers from iron deficiency and resulting anemia. In contrast, hereditary hemochromatosis is the most common monogeneous inherited disease (prevalence of homozygous genotype 1:200 - 300 in Germany). While iron-induced anemia can be handled by relatively simple diagnostic and therapeutic management, the diagnosis and quantification of organ iron overload is far more challenging. This is of great clinical impact, as the overall body and organ iron concentration is the crucial prognostic parameter in iron overload disease. In 2001 the international workshop of NIDDK (National Institute of Diabetes and Digestive and Kidney Diseases) concluded that a quantitative, noninvasive, safe, and accurate approach for the assessment of body iron storage is needed to improve the diagnosis and management of patients with iron overload.

Shiga toxin-producing E. coli O104:H4 outbreak 2011 in Germany: radiological features of enterohemorrhagic colitis.

PURPOSE: In 2011 a nationwide outbreak of Shiga toxin-producing E. coli (STEC) O104:H4 infection occurred in Germany with severe hemorrhagic colitis and hemolytic-uremic syndrome (HUS). We defined abdominal radiologic findings in these patients and correlated them with clinical parameters. MATERIALS AND METHODS: 23 patients (7 men; age: 48 ± 19 years) with O104:H4 colitis and/or HUS received abdominal CT (n = 12) or radiographs (n = 11). Colonic distension, air-fluid levels, and free intraabdominal air were assessed. Colonic wall thickening, contrast enhancement, pericolic stranding, and ascites were evaluated on CT. Laboratory parameters and clinical presentation were reviewed. Chi-square test, Student's t-test, McNemar's test and Spearman correlation were performed. RESULTS: Colonic lumen distension was seen in 16/23 patients (69.6 %). The ascending colon (11/23 patients; 47.8 %) and transverse colon (12/23 patients; 52.2 %) were dilated significantly more often (p = 0.006 and p = 0.003, respectively) than the descending colon (1/23; 4.3 %). All 12 patients undergoing CT scanning had abnormally thickened colonic wall segments, 3 (25 %) had pancolic involvement and 9 (75 %) had segmental involvement. The descending colon was predominantly affected (11/12 patients; 91.7 %) and thickened significantly more often than other colonic segments (p < 0.001). CONCLUSION: The segmental type of STEC O104:H4 colitis mainly affects the descending colon with upstream distension of the transverse/ascending colon and differs from other types of colitis.

Fractures of the thoracic spine in patients with minor trauma: comparison of diagnostic accuracy and dose of biplane radiography and MDCT.

OBJECTIVES: To investigate the accuracy of biplane radiography in the detection of fractures of the thoracic spine in patients with minor trauma using multidetector computed tomography (MDCT) as the reference and to compare the dose of both techniques. METHODS: 107 consecutive trauma patients with suspected fractures of the thoracic spine on physical examination were included. All had undergone biplane radiography first, followed by a MDCT scan between October 2008 and October 2012. A fourfold table was used for the classification of the screening test results. Both the Chi-square test (χ(2)) and the mean dose-length product (DLP) were used to compare the diagnostic methods. RESULTS: MDCT revealed 77 fractures in 65/107 patients (60.7%). Biplane radiography was true positive in 32/107 patients (29.9%), false positive in 19/107 patients (17.8%), true negative in 23/107 (21.5%) and false negative in 33/107 patients (30.8%), showing a sensitivity of 49.2%, a specificity of 54.7%, a positive predictive value (PPV) of 62.7%, a negative predictive value (NPV) of 41.1%, and an accuracy of 51.4%. The presence of a fracture on biplane radiography was highly statistical significant, if this was simultaneously proven by MDCT (χ(2)=7.6; p=0.01). None of the fractures missed on biplane radiography was unstable. The mean DLP on biplane radiography was 14.5mGycm (range 1.9-97.8) and on MDCT 374.6mGycm (range 80.2-871). CONCLUSIONS: The sensitivity and the specificity of biplane radiography in the diagnosis of fractures of the thoracic spine in patients with minor trauma are low. Considering the wide availability of MDCT that is usually necessary for taking significant therapeutic steps, the indication for biplane radiography should be very restrictive.