[Developmental disorders of the gastrointestinal tract]. / Entwicklungsstörungen des Gastrointestinaltrakts.

BACKGROUND: Developmental disorders of the gastrointestinal tract comprise a broad spectrum of congenital malformations of different etiologies and locations from the mouth to the anus. METHODS: The authors present the most important malformations of the gastrointestinal tract on the basis of basic and current reviews. RESULTS: Gastrointestinal developmental disorders occur both sporadically and in connection with malformation syndromes. Symptoms are highly variable and range from postnatal emergencies to asymptomatic abnormalities, which may be incidental radiological findings. Prenatal ultrasound examinations can often identify gastrointestinal developmental disorders at an early stage. Here, fetal magnetic resonance imaging can be a useful addition to the diagnostic process. In the first few days of life, simple X­ray overview images, supplemented by images after the administration of contrast medium, are often sufficient. CONCLUSION: Many patients with a malformation of the gastrointestinal tract require lifelong medical care, so that not only pediatric radiologists need specific knowledge about this group of diseases.

Reproducibility of non-contrast enhanced multi breath-hold ultrashort echo time functional lung MRI.

PURPOSE: To evaluate the intraindividual reproducibility of functional lung imaging using non-contrast enhanced multi breath-hold 3D-UTE MRI. METHODS: Ten healthy volunteers underwent non-contrast enhanced 3D-UTE MRI at three time points for same-day and different-day measurements employing a stack-of-spirals trajectory at 3 T. At each time point, inspiratory and expiratory breathing states were acquired for tidal and deep breathing, each within a single breath-hold. For functional image analysis, fractional ventilation (FV) was calculated pixelwise after image registration from the MR signal change. To decouple FV from breathing depth, the individual lung volume was used for volume adjustment (rFV). Reproducibility evaluation was performed in eight lung segments. Statistical analyses included two way mixed intraclass correlation (ICC), sign-test, Friedman-test and modified Bland-Altman analyses. RESULTS: FV from tidal breathing showed an ICC of 0.81, a bias of 1.3% and an interval of confidence (CI) ranging from -67.1 to 69.6%. FV from deep breathing was higher reproducible with an ICC of 0.92 (bias, -0.2%; CI, -34.2 to 33.7%). Following volume adjustment, reproducibility of rFV for tidal breathing improved (ICC, 0,86; bias, 2.0%; CI, -34.3 to 38.3%), whereas it did not bear significant benefits for deep breathing (ICC, 0.89; bias, 2.8%; CI, -24.9 to 30.5%). Reproducibility was independent from the examination day. CONCLUSION: Non-contrast-enhanced multi breath-hold 3D-UTE MRI allows for highly reproducible ventilation imaging.

Non-contrast pulmonary perfusion MRI in patients with cystic fibrosis.

PURPOSE: This study aimed to assess the feasibility of Self-gated Non-Contrast-Enhanced Functional Lung (SENCEFUL) MRI for detection of pulmonary perfusion deficits in patients with cystic fibrosis. METHODS: Twenty patients with cystic fibrosis and 20 matched healthy controls underwent SENCEFUL-MRI at 1.5 T with reconstruction of perfusion and perfusion phase maps (i.e. comparable to pulse wave delays). Four blinded readers rated both types of maps separately followed by simultaneous assessment thereof. Perfusion phase data was plotted in histograms and a Peak-to-Offset ratio was calculated for comparison to subjective scoring and correlation (Spearman) to lung function parameters. Sensitivity, specificity and positive and negative predictive values were calculated for subjective scoring and Peak-to-Offset ratios. Intraclass correlation (ICC) was used to assess the interrater agreement. RESULTS: Readers attributed pathological ratings 2.2-3.5 times more frequently to the CF-group. The sensitivity with regard to a correct assignment to CF was similar between ratings (perfusion only vs. perfusions phase only vs. simultaneous assessment: 0.54-0.56), while specificity increased from 0.75 to 0.85 for simultaneous assessment. ICC was 0.77-0.84 for subjective scoring. ROC-analysis of Peak-to-Offset ratios on a mean per-subject basis revealed a sensitivity of 0.75 and specificity of 0.85 (PPV 0.83, NPV 0.77). Functional pulmonary parameters indicative of bronchial obstruction and Peak-to-Offset ratios showed positive correlation (FEV1: 0.77; FEF75: 0.76). CONCLUSIONS: SENCEFUL-MRI bears the potential for monitoring CF including disease-associated patterns of altered pulmonary perfusion. The proposed Peak-to-Offset ratio derived from pulmonary perfusion phase measurements could represent an objective future marker for perfusion impairment.

UTE-SENCEFUL: first results for 3D high-resolution lung ventilation imaging.

PURPOSE: This study aimed to develop a 3D MRI technique to assess lung ventilation in free-breathing and without the administration of contrast agent. METHODS: A 3D-UTE sequence with a koosh ball trajectory was developed for a 3 Tesla scanner. An oversampled k-space was acquired, and the direct current signal from the k-space center was used as a navigator to sort the acquired data into 8 individual breathing phases. Gradient delays were corrected, and iterative SENSE was used to reconstruct the individual timeframes. Subsequently, the signal changes caused by motion were eliminated using a 3D image registration technique, and ventilation-weighted maps were created by analyzing the signal changes in the lung tissue. Six healthy volunteers and 1 patient with lung cancer were scanned with the new 3D-UTE and the standard 2D technique. Image quality and quantitative ventilation values were compared between both methods. RESULTS: UTE-based self-gated noncontrast-enhanced functional lung (SENCEFUL) MRI provided a time-resolved reconstruction of the breathing motion, with a 49% increase of the SNR. Ventilation quantification for healthy subjects was in statistical agreement with 2D-SENCEFUL and the literature, with a mean value of 0.11 ± 0.08 mL/mL for the whole lung. UTE-SENCEFUL was able to visualize and quantify ventilation deficits in a patient with lung tumor that were not properly depicted by 2D-SENCEFUL. CONCLUSION: UTE-SENCEFUL represents a robust MRI method to assess both morphological and functional information of the lungs in 3D. When compared to the 2D approach, 3D-UTE offered ventilation maps with higher resolution, improved SNR, and reduced ventilation artifacts.

Magnetic Particle Imaging for Quantification of Vascular Stenoses: A Phantom Study.

Magnetic particle imaging (MPI) is a promising new tomographic imaging method to detect the spatial distribution of superparamagnetic iron-oxide nanoparticles (SPIOs). The aim of this paper was to investigate the potential of MPI to quantify artificial stenoses in vessel phantoms. Custom-made stenosis phantoms (length 40 mm; inner diameter 8 mm) with different degrees of stenosis (0%, 25%, 50%, 75%, and 100%) were scanned in a custom-built MPI scanner (in-plane resolution: ~1-1.5 mm and field of view: 65 29 29 mm3). Phantoms were filled with diluted Feru-carbotran [SPIO agent, 5 mmol (Fe)/l]. Each measurement (overall acquisition time: 20 ms per image, 400 averages) was repeated ten times to assess reproducibility. The MPI signal was used for semi-automatic stenosis quantification. Two stenosis evaluation approaches were compared based on the signal intensity profile alongside the stenosis phantoms. Using a novel multi-step image evaluation approach, MPI allowed for accurate quantification of different stenosis grades. While low grade stenoses were slightly over-estimated, high grade stenoses were slightly underestimated. In particular, the 0%, 25%, and 50% stenosis phantoms revealed a 6.2% ± 0.8, 25.7% ± 1.0, and 48.0% ± 1.5 stenosis, respectively. The higher grade 75% stenosis phantom revealed a 73.3% ± 2.8 and the 100% stenosis phantom a 95.8%± 1.9 stenosis. MPI accurately visualized and quantified different stenosis grades in vessel phantoms with high reproducibility demonstrating its great potential for fast and radiation-free preclinical cardiovascular imaging.

Age-related differences in the activity of arterial mineral deposition and regional bone metabolism: a 18F-sodium fluoride positron emission tomography study.

UNLABELLED: Functional (18)F-fluoride PET demonstrated an inverse relationship between the activity of arterial mineral deposition and regional bone metabolism. While bone metabolism decreases with age, the activity of arterial mineral deposition increases. INTRODUCTION: The extent of arterial calcification increases with age, whereas bone mineral density decreases, evidencing a well-known inverse correlation on morphological basis. The aim of this study was to evaluate the functional relationship between the activity of arterial mineral deposition and regional bone metabolism as assessed by (18)F-sodium fluoride (NaF) PET/CT. METHODS: Three hundred four subjects were examined by (18)F-NaF PET/CT. Tracer accumulation in the femoral arteries was analyzed both qualitatively and semiquantitatively by measuring the blood-pool-corrected standardized uptake value (target-to-background ratio). Uptake was compared with cardiovascular risk factors (RFs), calcified plaque burden, and regional bone metabolism as assessed by PET/CT. RESULTS: The activity of arterial mineral deposition significantly increased with age (p < 0.001), whereas regional bone metabolism significantly decreased (p < 0.001). There was a significant inverse correlation between bone metabolism and arterial mineral deposition (unadjusted, p < 0.001); that association was not significant (p = 0.79) when controlled for age and other RFs. Both high activity of arterial mineral deposition and low bone metabolism were significantly associated with cardiovascular events and other RFs. CONCLUSION: (18)F-NaF PET/CT provides a tool to visualize and quantify the activity of arterial mineral deposition and regional bone metabolism. In this study, we observed an inverse correlation between the activity of arterial mineral deposition and regional bone metabolism. While the activity of arterial mineral deposition significantly increases with age, regional bone metabolism decreases.

[Diagnostics and therapy of achalasia]. / Diagnostik und Therapie der Achalasie.

The low incidence (1:100,000) makes primary idiopathic achalasia a problem of special importance. Patients often have a long medical history of suffering before the diagnosis is established and adequate therapy provided. Surgeons who perform antireflux surgery must be certain of detecting achalasia patients within their collective of gastroesophageal reflux disease (GERD) patients to avoid contraindicated fundoplication. The current gold standard for establishing the diagnosis of achalasia is manometry. Especially in early stages, symptom evaluation, endoscopy and barium swallow lack adequate sensitivity. High-resolution manometry (HRM) is increasingly used and allows characterization of different achalasia types (i.e. type I classical achalasia, type II panesophageal pressurization and type III spasmodic achalasia) and differentiation from other motility disorders (e.g. distal esophageal spasm, jackhammer esophagus and nutcracker esophagus). For patients over 45 years of age additional endoscopic ultrasound and computed tomography are recommended to exclude pseudoachalasia. A curative treatment restoring normal esophageal function does not exist; however, there are good options for symptom control. Therapy aims are abolishment of dysphagia, improvement of esophageal clearance, prevention of reflux and abolishment of chest pain. The current standard treatment is cardiomyotomy, which was first described 100 years ago by the German surgeon Ernst Heller and has been shown to be clearly superior when compared to endoscopic treatment (e.g. botox injection and balloon dilatation). Heller's myotomy procedure is preferentially performed via the laparoscopic route and combined with partial fundoplication. Currently, an alternative to performing Heller's myotomy via the endoscopic route is under intensive investigation in several centers worldwide. The peroral endoscopic myotomy (POEM) procedure has shown very promising initial results and warrants further clinical evaluation.

Pediatric patients with Marfan syndrome: frequency of dural ectasia and its correlation with common cardiovascular manifestations.

PURPOSE: Marfan syndrome (MFS) is a genetic disorder of the connective tissue. Aortic root dilation is a main criterion of the Ghent Nosology. Dural ectasia and the presence of mitral valve prolapse (MVP) contribute to its systemic score. The purpose of this study was to investigate the frequency of dural ectasia and its correlation with cardiovascular manifestations in a pediatric study population. PATIENTS AND METHODS: 119 pediatric patients with confirmed or suspected MFS were examined in the local Marfan Clinic. 31 children with MFS who underwent magnetic resonance imaging (MRI) were included. Each patient was evaluated according to the Ghent nosology. Echocardiography was used to measure the aortic root diameter and assess the presence of MVP and mitral regurgitation. Z-scores were calculated for the evaluation of the aortic root diameters. MRI was performed to determine the dural sac ratio (DSR). RESULTS: The prevalence of dural ectasia was 90.3 %, of aortic root dilation 32.2 %, of MVP 64.5 % and of mitral regurgitation 51.6 %. DSR at L5 correlated with the intraindividual z-scores (slope, 3.62 ±â€Š1.5 [0.56; 6.68]; r = 0.17; p = 0.02; F = 5.84). Z-scores ≥ 2 were accompanied by dural ectasia in 100 %, MVP in 95 % and mitral regurgitation in 100 % of cases. MVP was accompanied by mitral regurgitation in 70 % of cases. CONCLUSION: As the examined cardiac manifestations show a coincidence with dural ectasia in 95 - 100 % of cases, MRI for diagnostic dural sac imaging should be reserved for MFS suspicions with the absence of those manifestations in order to establish the diagnosis according to the Ghent criteria. Thus, the present study supports the recent downgrading of dural ectasia to a contributor to the systemic score.