Analysis and predictability of technologists' perception of MR exam complexity.

INTRODUCTION: As MRI becomes a routine clinical diagnostic method, its complexity of techniques, protocols and scanning is growing. On the other hand, aggravated by the ubiquitous shortage of workforce, technologists' stress level and burnout rates are increasing. In this context, our study aims to shed light on technologists' perceived complexity of MR exams, by analyzing a multidimensional dataset composed of workflow, patient, and operational details, and further predicting perceived exam complexity. METHODS: In this IRB-approved study, data about imaging workflow, exam context, and patient characteristics were collected over one year from MR modality logfiles and from technologist questionnaires, including the perceived exam complexity. The association of individual factors with complexity was analyzed via Fisher's exact tests and Cramér's V values. Predictability of exam complexity was further evaluated via ROC analysis of three different multivariate classifiers. RESULTS: Retakes, delays, and extended exam duration are associated with perceived complexity (V ≥ 0.2). From the set of possible predictors, patient mobility and communication ability have the most influence on perceived complexity (V > 0.2), followed by special equipment needs (pulse oximetry, intubation, or ECG), protocol details and other patient characteristics. Feasibility of predicting the perceived exam complexity from a multivariate set of exam and patient details known at the time of scheduling has been demonstrated (AUC = 0.73), and suitable classification algorithms have been identified. CONCLUSION: Perceived exam complexity is associated with various factors. Our results suggest that it can be predicted sufficiently well to support early operational decision making. Some factors, however, may not be readily available in hospital IT systems and must be obtained before scheduling. IMPLICATIONS FOR PRACTICE: Results and observations of this study could be utilized to assist operational scheduling in the radiology department and reduce MR technologists' stress levels.

Correlation of the Histological ICRS II Score and the 3D MOCART Score for the Analysis of Aged Osteochondral Regenerates in a Large Animal Model.

OBJECTIVE: Reliable outcome measures are essential to predict the success of cartilage repair techniques. Histology is probably the gold standard, but magnetic resonance imaging (MRI) has the potential to decrease the need for invasive histological biopsies. The 3D magnetic resonance observation of cartilage repair tissue (MOCART) score is a reliable yet elaborate tool. Moreover, literature is controversial concerning the correlation of histology and MRI. DESIGN: To test the applicability of the International Cartilage Regeneration and Joint Preservation Society (ICRS) II and MOCART 3D score for the evaluation of aged osteochondral regenerates in a large animal model, and to identify correlating histological and MRI parameters. Osteochondral defects in medial femoral condyles of n = 12 adult sheep were reconstructed with biodegradable bilayer implants. About 19.5 months postoperation, n = 10 joints were analyzed with MRI (3D MOCART score). Histological samples were analyzed using the ICRS II score; both pre- and post-training. The intraclass correlation coefficient, the inter-rater reliability, and the 95% confidence interval were calculated. Matching histological and MRI parameters were tested for correlation. RESULTS: We found a statistically significant correlation of all histological parameters. MRI parameters reflecting "overall" assessments had very strong inter-rater correlations. Statistically significant strong correlations were found for the MRI parameters defect filling, cartilage interface, bone interface, and surface. For defect overall (MRI) and overall assessment (ICRS II), we found a significant yet mild correlation. CONCLUSIONS: The ICRS II and the 3D MOCART score are applicable to aged osteochondral regenerates. Prior training on the scoring systems is essential. Select MRI and histological parameters correlate; however, the only statistically significant correlation was found for overall assessment.

Rapid study assessment in follow-up whole-body computed tomography in patients with multiple myeloma using a dedicated bone subtraction software.

OBJECTIVES: The diagnostic reading of follow-up low-dose whole-body computed tomography (WBCT) examinations in patients with multiple myeloma (MM) is a demanding process. This study aimed to evaluate the diagnostic accuracy and benefit of a novel software program providing rapid-subtraction maps for bone lesion change detection. METHODS: Sixty patients (66 years ± 10 years) receiving 120 WBCT examinations for follow-up evaluation of MM bone disease were identified from our imaging archive. The median follow-up time was 292 days (range 200-641 days). Subtraction maps were calculated from 2-mm CT images using a nonlinear deformation algorithm. Reading time, correctly assessed lesions, and disease classification were compared to a standard reading software program. De novo clinical reading by a senior radiologist served as the reference standard. Statistics included Wilcoxon rank-sum test, Cohen's kappa coefficient, and calculation of sensitivity, specificity, positive/negative predictive value, and accuracy. RESULTS: Calculation time for subtraction maps was 84 s ± 24 s. Both readers reported exams faster using subtraction maps (reader A, 438 s ± 133 s; reader B, 1049 s ± 438 s) compared to PACS software (reader A, 534 s ± 156 s; reader B, 1486 s ± 587 s; p < 0.01). The course of disease was correctly classified by both methods in all patients. Sensitivity for lesion detection in subtraction maps/conventional reading was 92%/80% for reader A and 88%/76% for reader B. Specificity was 98%/100% for reader A and 95%/96% for reader B. CONCLUSION: A software program for the rapid-subtraction map calculation of follow-up WBCT scans has been successfully tested and seems suited for application in clinical routine. Subtraction maps significantly facilitated reading of WBCTs by reducing reading time and increasing sensitivity. KEY POINTS: • A novel algorithm has been successfully applied to generate motion-corrected bone subtraction maps of whole-body low-dose CT scans in less than 2 min. • Motion-corrected bone subtraction maps significantly facilitate the reading of follow-up whole-body low-dose CT scans in multiple myeloma by reducing reading time and increasing sensitivity.

Comparison of radial 4D Flow-MRI with perivascular ultrasound to quantify blood flow in the abdomen and introduction of a porcine model of pre-hepatic portal hypertension.

OBJECTIVES: Objectives of this study were to compare radial time-resolved phase contrast magnetic resonance imaging (4D Flow-MRI) with perivascular ultrasound (pvUS) and to explore a porcine model of acute pre-hepatic portal hypertension (PHTN). METHODS: Abdominal 4D Flow-MRI and pvUS in portal and splenic vein, hepatic and both renal arteries were performed in 13 pigs of approximately 60 kg. In six pigs, measurements were repeated after partial portal vein (PV) ligature. Inter- and intra-reader comparisons and statistical analysis including Bland-Altman (BA) comparison, paired Student's t tests and linear regression were performed. RESULTS: PvUS and 4D Flow-MRI measurements agreed well; flow before partial PV ligature was 322 ± 30 ml/min in pvUS and 297 ± 27 ml/min in MRI (p = 0.294), and average BA difference was 25 ml/min [-322; 372]. Inter- and intra-reader results differed very little, revealed excellent correlation (R 2 = 0.98 and 0.99, respectively) and resulted in BA differences of -5 ml/min [-161; 150] and -2 ml/min [-28; 25], respectively. After PV ligature, PV flow decreased from 356 ± 50 to 298 ± 61 ml/min (p = 0.02), and hepatic arterial flow increased from 277 ± 36 to 331 ± 65 ml/min (p = n.s.). CONCLUSION: The successful in vivo comparison of radial 4D Flow-MRI to perivascular ultrasound revealed good agreement of abdominal blood flow although with considerable spread of results. A model of pre-hepatic PHTN was successfully introduced and acute responses monitored. KEY POINTS: • Radial 4D Flow-MRI in the abdomen was successfully compared to perivascular ultrasound. • Inter- and intra-reader testing demonstrated excellent reproducibility of upper abdominal 4D Flow-MRI. • A porcine model of acute pre-hepatic portal hypertension was successfully introduced. • 4D Flow-MRI successfully monitored acute changes in a model of portal hypertension.

Four-dimensional velocity mapping of the hepatic and splanchnic vasculature with radial sampling at 3 tesla: a feasibility study in portal hypertension.

PURPOSE: To demonstrate the feasibility of PC-VIPR (Phase Contrast Vastly undersampled Imaging with Projection Reconstruction) for the depiction and hemodynamic analysis of hepatic and splanchnic vessels in patients with portal hypertension. MATERIALS AND METHODS: Twenty-four cirrhotic patients (55.9 ± 10.4 years) were scanned using 5-point PC-VIPR for high spatial resolution imaging with large volume coverage at 3 Tesla (T) using a 32-channel body coil. Vessel segmentation and hemodynamic visualization included color-coded three-dimensional (3D) streamlines and particle traces. Segmentation quality was compared with contrast-enhanced multi-phase liver imaging. Flow pattern analysis was performed in consensus of three readers. The MELD score was calculated to estimate disease severity and was correlated to image quality. RESULTS: Good to excellent visualization quality was achieved in 23/24 cases. All arterial vessels and 144/168 vessels of the portal venous (PV) circulation were unambiguously identified. No correlation with the MELD score was found. Eight of 148 vessels of the PV circulation demonstrated reverse (hepatofugal) flow. Hepatofugal flow in small tributaries to PV flow were present in three cases despite hepatopetal flow in the PV. CONCLUSION: This feasibility study demonstrates the feasibility of PC-VIPR for simultaneous morphological and hemodynamic assessment of the hepatic and splanchnic vasculature in cirrhosis and portal hypertension. Future studies with quantitative analyses are warranted.

Rapidly progressive hepatic alveolar echinococcosis in an ABO-incompatible renal transplant recipient.

We report on the case of an ABO-incompatible renal re-transplant recipient maintained on an intensified immunosuppressive regimen for recurrent cellular rejection episodes and transplant glomerulopathy who presented with rapidly growing hepatic tumors, radiologically suggestive of hemangiosarcoma. Upon resection and pathological work-up, the lesions revealed alveolar echinococcosis, a rare but potentially life-threatening parasitosis. Usually infection with Echinococcus multilocularis remains asymptomatic for extended periods of time and can go unrecognized for years. In the case presented, we observed an atypically rapid growth pattern of E. multilocularis that might have been due to the extent of the immunosuppressive regimen, which included repetitive anti-CD20 treatments. Retrospectively performed serological studies with enzyme-linked immunosorbent assays known to provide high sensitivity and specificity for the detection of echinococcosis in the general population, yielded ambiguous results in our immunocompromised host, which could be, in part, explained by B-cell depletion and its effects on antibody production and indirect actions on cellular immunity. In conclusion, this is the first report to our knowledge of hepatic alveolar echinococcosis in a renal transplant recipient. This case documents an altered clinical course of the parasitosis and the challenge of serological diagnostic tools under an intensified regimen of immunosuppressive agents, including rituximab.

The effect of spatial resolution on wall shear stress measurements acquired using radial phase contrast magnetic resonance angiography in the middle cerebral arteries of healthy volunteers. Preliminary results.

We have recently implemented radial phase-contrast techniques that allow high resolution angiograms with velocity information to be acquired within clinically-useful imaging times. 10 healthy volunteers were scanned using PC-VIPR and PC-SOS, two high resolution phase-contrast techniques at spatial resolutions of 0.67×0.67×0.67 mm(3) and 0.4×0.4×1 mm(3) respectively. The velocity measurements from the two acquisitions were imported into a custom Matlab runtime environment that automatically calculated WSS values using Green's Theorem and B-spline interpolation. Time average axial WSS was 1.069 N/m(2) (95% confidence interval: 0.8628< x < 1.276) in the left and right middle cerebral arteries of the 10 healthy volunteers (n=20) when scanned by PC-VIPR, and 1.670 N/m(2) when scanned by PC-SOS (95% confidence interval: 1.395 < x < 1.946). This difference in means was statistically significant (p < 0.002). Previous investigators have found that higher spatial resolution results in higher WSS measurements because smaller voxel size results in fewer partial volume effects. This was true in our study as well. In this study, we found that PC-SOS has significantly higher spatial resolution than PC-VIPR and this followed in the WSS measurements. Higher in-plane spatial resolution allows WSS calculations to be performed more accurately because of increased precision near the vessel boundary.

[Diagnosing stroke aetiologies. Morphologic and functional analysis of the aorta and carotid arteries by MRI]. / Diagnostik von Schlaganfallursachen. Morphologische und funktionelle MRT-Darstellung der Aorta und der Karotiden.

Magnetic resonance imaging allows detailed visualization of the thoracic aorta and is not limited by air artefacts or insonation angles like transoesophageal echocardiography (TEE). Thus the aortic arch can be investigated with higher accuracy, and additional embolic high-risk sources such as complex plaques can be additionally detected by MRI in patients with cryptogenic stroke. Furthermore, MRI provides exact 3D plaque localisation and can be combined with multidirectional 3D MRI velocity mapping. In this way, previously not demonstrable retrograde flow paths originating at complex descending aortic plaques reaching the supra-aortic great arteries can be identified as the probable stroke mechanism in certain patients. The same technique can also be applied to the carotid arteries. This allows analysing the complex 3D helical flow within the internal carotid artery as well as measuring absolute flow velocities and wall shear stress in combination with data on vessel anatomy derived from conventional MR angiography. It is the purpose of this work to describe the state of the art of these modern MR imaging techniques and their potential to identify potential stroke mechanisms, and to analyse the particular role of individual haemodynamic factors on the development of local atherosclerosis.

3D blood flow characteristics in the carotid artery bifurcation assessed by flow-sensitive 4D MRI at 3T.

To determine three-dimensional (3D) blood flow patterns in the carotid bifurcation, 10 healthy volunteers and nine patients with internal carotid artery (ICA) stenosis > or =50% were examined by flow-sensitive 4D MRI at 3T. Absolute and mean blood velocities, pulsatility index (PI), and resistance index (RI) were measured in the common carotid arteries (CCAs) by duplex sonography (DS) and compared with flow-sensitive 4D MRI. Furthermore, 3D MRI blood flow patterns in the carotid bifurcation of volunteers and patients before and after recanalization were graded by two independent readers. Blood flow velocities measured by MRI were 31-39% lower than in DS. However, PI and RI differed by only 13-16%. Rating of 3D flow characteristics in the ICA revealed consistent patterns for filling and helical flow in volunteers. In patients with ICA stenosis, 3D blood flow visualization was successfully employed to detect markedly altered filling and helical flow patterns (forward-moving spiral flow) in the ICA bulb and to evaluate the effect of revascularization, which restored filling and helical flow. Our results demonstrate the feasibility of flow-sensitive 4D MRI for the quantification and 3D visualization of physiological and pathological flow patterns in the carotid artery bifurcation.

Quantitative 2D and 3D phase contrast MRI: optimized analysis of blood flow and vessel wall parameters.

Quantification of CINE phase contrast (PC)-MRI data is a challenging task because of the limited spatiotemporal resolution and signal-to-noise ratio (SNR). The method presented in this work combines B-spline interpolation and Green's theorem to provide optimized quantification of blood flow and vessel wall parameters. The B-spline model provided optimal derivatives of the measured three-directional blood velocities onto the vessel contour, as required for vectorial wall shear stress (WSS) computation. Eight planes distributed along the entire thoracic aorta were evaluated in a 19-volunteer study using both high-spatiotemporal-resolution planar two-dimensional (2D)-CINE-PC ( approximately 1.4 x 1.4 mm(2)/24.4 ms) and lower-resolution 3D-CINE-PC ( approximately 2.8 x 1.6 x 3 mm(3)/48.6 ms) with three-directional velocity encoding. Synthetic data, error propagation, and interindividual, intermodality, and interobserver variability were used to evaluate the reliability and reproducibility of the method. While the impact of MR measurement noise was only minor, the limited resolution of PC-MRI introduced systematic WSS underestimations. In vivo data demonstrated close agreement for flow and WSS between 2D- and 3D-CINE-PC as well as observers, and confirmed the reliability of the method. WSS analysis along the aorta revealed the presence of a circumferential WSS component accounting for 10-20%. Initial results in a patient with atherosclerosis suggest the potential of the method for understanding the formation and progression of cardiovascular diseases.

Balanced left ventricular myocardial SSFP-tagging at 1.5T and 3T.

The purpose of the study was to evaluate the performance of steady-state free precession (SSFP)-tagging at 1.5T and 3T and to define the ideal settings with respect to optimized tag contrast throughout the cardiac cycle for both field strengths. To identify optimal imaging parameters data acquisition was repeated for different flip angles. Left ventricular tag-tissue contrast, tag fading times, tag persistence, and myocardial signal-to-noise ratio (SNR) were quantified in basal, mid-ventricular, and apical slice locations. To assess the effect of field strength on image quality and artifact level, additional semiquantitative image grading was performed by two experienced readers. SSFP-tagging at 3T proved superior to 1.5T and provided significantly enhanced tag persistence and myocardial SNR while maintaining overall image quality and artifact level. The definition of a tag quality index demonstrated optimal SSFP-tagging performance for a flip angle of 20 degrees . Diastolic tag visibility was improved at 3T and resulted in enhanced average tag persistence of 789 +/- 128 ms compared to 523 +/- 40 ms at 1.5T. For SSFP-tagging at 3T the combination of T(1) lengthening and superior myocardial SNR is highly promising and has the potential to improve the depiction of tagged myocardial function throughout the entire cardiac cycle.

3D MR flow analysis in realistic rapid-prototyping model systems of the thoracic aorta: comparison with in vivo data and computational fluid dynamics in identical vessel geometries.

The knowledge of local vascular anatomy and function in the human body is of high interest for the diagnosis and treatment of cardiovascular disease. A comprehensive analysis of the hemodynamics in the thoracic aorta is presented based on the integration of flow-sensitive 4D MRI with state-of-the-art rapid prototyping technology and computational fluid dynamics (CFD). Rapid prototyping was used to transform aortic geometries as measured by contrast-enhanced MR angiography into realistic vascular models with large anatomical coverage. Integration into a flow circuit with patient-specific pulsatile in-flow conditions and application of flow-sensitive 4D MRI permitted detailed analysis of local and global 3D flow dynamics in a realistic vascular geometry. Visualization of characteristic 3D flow patterns and quantitative comparisons of the in vitro experiments with in vivo data and CFD simulations in identical vascular geometries were performed to evaluate the accuracy of vascular model systems. The results indicate the potential of such patient-specific model systems for detailed experimental simulation of realistic vascular hemodynamics. Further studies are warranted to examine the influence of refined boundary conditions of the human circulatory system such as fluid-wall interaction and their effect on normal and pathological blood flow characteristics associated with vascular geometry.

Mural inflammatory hyperenhancement in MRI of giant cell (temporal) arteritis resolves under corticosteroid treatment.

OBJECTIVE: To determine the effect of corticosteroid treatment on mural inflammatory hyperenhancement in MRI in GCA. METHODS: MRI of the superficial temporal artery with sub-millimetre in-plane spatial resolution (195 x 260 microm) was performed in 17 patients with proven GCA at the initiation of corticosteroid treatment and after 16 months of therapy. Visual MRI scores for mural inflammation were correlated with clinical and laboratory findings. RESULTS: Intensity of inflammatory hyperenhancement decreased significantly under corticosteroid therapy (2.3 +/- 0.6 vs 0.5 +/- 0.6, P < 0.001, with MRI score >2 indicating vasculitis). This finding correlated with the clinical and serological remission in 15/17 patients. Of the two patients with active disease, one had persisting mural inflammation in MRI indicative of relapsing disease. The other patient presenting with signs of polymyalgia rheumatica had no inflammatory changes of the superficial temporal arteries on MRI scan at follow-up. CONCLUSIONS: Mural contrast enhancement in high-resolution MRI is pronounced in active disease and decreases under corticosteroid treatment, correlating well with laboratory remission.

Reliability of aortic MRI at 3 Tesla in patients with acute cryptogenic stroke.

OBJECTIVES: To evaluate a new three dimensional (3D) MRI protocol for the reliable detection of aortic high risk plaques compared with transoesophageal echocardiography (TOE) and to test the reliability of additional MRI in stroke of undetermined aetiology. METHODS: 74 acute stroke patients were examined by both TOE and MRI at 3 Tesla with special regard to aortic high risk plaques (ie, > OR = 4 mm, superimposed thrombi). ECG synchronised pre- and post-contrast T1 weighted 3D imaging (spatial resolution approximately 1 mm3) covering the thoracic aorta was employed. In plaques > OR = 3 mm, additional two dimensional T2 imaging and time resolved (CINE) imaging sequences were performed. Aetiology of brain ischaemia was classified according to modified TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria. Aortic high risk embolic sources detected by MRI in patients with cryptogenic stroke were evaluated. RESULTS: Differences in maximum aortic wall thickness for TOE and MRI were not statistically significant for all aortic segments. The overall number of high risk plaques detected by MRI (n = 74) was substantially higher compared with TOE (n = 47). Most noticeably, MRI identified aortic high risk pathologies in 8/26 (30.8%) patients with cryptogenic stroke after standard diagnostics, including TOE (n = 2: dissection or thrombus; n = 6: plaques > OR = 4 mm). CONCLUSIONS: Our results demonstrate the feasibility of this 3D MRI protocol for the reliable detection of aortic high risk plaques in acute stroke patients. Because of improved visualisation of the aortic arch and the detection of additional embolic sources not seen by standard diagnostics, this novel technique may become a valuable tool for future patients with cryptogenic stroke.

[MR-based tridirectional flow imaging. Acquisition and 3D analysis of flows in the thoracic aorta]. / MRT-basierte tridirektionale Flussbildgebung. Aufnahme und 3D-Analyse von Strömungen in der thorakalen Aorta.

Tridirectional MR flow imaging is a novel method that extends the well-established technique of phase-contrast flow measurement by vectorial velocity encoding, i.e., by encoding in all three spatial directions. Modern sequence protocols allow the acquisition of velocity vector fields with high spatial resolutions of 1-3 mm and temporal resolutions of 20-50 ms over the heart cycle. Using navigating techniques, data on the entire thoracic aorta can be acquired within about 20 min in free breathing. The subsequent computer-based data processing includes automatic correction of aliasing effects, eddy currents, gradient field inhomogeneities, and Maxwell terms. The data can be visualized in three dimensions using vector arrows, streamlines, or particle traces. The parallel visualization of morphological slices and of the surface of the vascular lumen in 3D enhances spatial and anatomical orientation. Furthermore, quantitative values such as blood flow velocity and volume, vorticity, and vessel wall shear stress can be determined. Modern software systems support the integrated flow-based analysis of typical aortic pathologies such as aneurysms and aortic insufficiency. To what extent this additional information will help us in making better therapeutic decisions needs to be studied in clinical trials.

[MRI in giant cell (temporal) arteritis]. / Magnetresonanztomografie der Arteriitis temporalis Horton.

Giant cell (temporal) arteritis is a diagnostic challenge. Blindness is a dreaded complication, especially if high-dose steroid treatment is delayed. With an optimized MR protocol, noninvasive diagnosis of giant cell arteritis is facilitated. Submillimeter in-plane resolution makes it possible to distinguish healthy segments from inflamed segments. The lumen and arterial wall can be depicted in high detail. Post-contrast high-resolution MRI visualizes the superficial cranial arteries bilaterally and simultaneously, allowing assessment of the cranial involvement pattern. In combination with MR angiography of the aortic arch and supra-aortic arteries, the extracranial involvement pattern can be demonstrated in a single comprehensive MR examination assessing the cranial, cervical and thoracic vasculature. Good diagnostic image quality can be achieved at 1.5 Tesla and at 3 Tesla. However, due to higher signal-to-noise ratios, image quality seems to be superior at 3 Tesla. Over the course of successful long-term treatment, MR signs of mural inflammation decrease significantly and eventually vanish entirely. In contrast to color-coded Duplex sonography, which is a comparatively cost-efficient imaging modality, acquisition of high-resolution MRI is almost independent of the investigator's expertise. Compared to positron emission tomography with 18F-fluoro-2-deoxy-D-glucose, which is a very sensitive whole-body screening tool for detecting extracranial involvement of large vessel vasculitis, MRI allows visualization and assessment of both the superficial cranial arteries in high detail and the extracranial large artery involvement in the same investigation.

[Flow-sensitive in-vivo 4D MR imaging at 3T for the analysis of aortic hemodynamics and derived vessel wall parameters]. / Die Analyse aortaler Hämodynamik und Gefässwandparameter mittels fluss-sensitiver in-vivo 4D-MRT bei 3 Tesla.

Modern phase contrast MR imaging at 3 Tesla allows the depiction of 3D morphology as well as the acquisition of time-resolved blood flow velocities in 3 directions. In combination with state-of-the-art visualization and data processing software, the qualitative and quantitative analysis of hemodynamic changes associated with vascular pathologies is possible. The 4D nature of the acquired data permits free orientation within the vascular system of interest and offers the opportunity to quantify blood flow and derived vessel wall parameters at any desired location within the data volume without being dependent on predefined 2D slices. The technique has the potential of overcoming the limitations of current diagnostic strategies and of implementing new diagnostic parameters. In light of the recent discussions regarding the influence of the wall shear stress and the oscillatory shear index on the genesis of arteriosclerosis and dilatative vascular processes, flow-sensitive 4D MRI may provide the missing diagnostic link. Instead of relying on experience-based parameters such as aneurysm size, new hemodynamic considerations can deepen our understanding of vascular pathologies. This overview reviews the underlying methodology at 3T, the literature on time-resolved 3D MR velocity mapping, and presents case examples. By presenting the pre- and postoperative assessment of hemodynamics in a thoracic aortic aneurysm and the detailed analysis of blood flow in a patient with coarctation we underline the potential of time-resolved 3D phase contrast MR at 3T for hemodynamic assessment of vascular pathologies, especially in the thoracic aorta.

In vivo assessment and visualization of intracranial arterial hemodynamics with flow-sensitized 4D MR imaging at 3T.

SUMMARY: We evaluated electrocardiogram-synchronized flow-sensitized 4-dimensional MR imaging at 3T in combination with advanced 3D visualization strategies to ascertain its feasibility for the assessment of local intracranial blood-flow patterns in vivo. In large arteries of healthy volunteers, the temporal and spatial evolution of blood flow was successfully visualized and revealed--for example, a helical flow pattern in the carotid siphon. In a patient with steno-occlusive neurovascular disease, stagnant and retrograde flow patterns were readily visible.

Functional assessment of isolated right heart failure by high resolution in-vivo cardiovascular magnetic resonance in mice.

Precise and noninvasive characterization of the development of the cardiac phenotype in murine models of heart failure has been widely demanded in modern cardiovascular research. High-resolution cardiovascular magnetic resonance (CMR) has been proven to be a powerful tool for the accurate and reproducible assessment of LV and RV parameters in healthy mice. Whereas changes in LV parameters in models of heart failure have been thoroughly evaluated, RV dysfunction has not. Purpose of this study was to characterize a model of isolated RV failure induced by pulmonal banding by in vivo CMR at 7T. RV parameters differed significantly from those of normal mice in terms of RV end-diastolic volume (EDV: 85 +/- 14 microL vs. control 36 +/- 3 microL, p < 0.0001), RV end-systolic volume (ESV: 121 +/- 10 microL vs. control 84 +/- 4 microL, p < 0.005) and RV ejection fraction (EF: 31 +/- 6 % vs. control 57 +/- 2 %, p < 0.001). With regard to EDV, ESV, SV and EF LV parameters, there were no significant differences between pulmonary banded and control mice indicating overt isolated RV failure.

Actual management of patients with familial ascending aortic aneurysms and type-A aortic dissections.

BACKGROUND: There are few families with the diagnosis of ascending aortic aneurysm and acute type-A aortic dissection inherited as an autosomal-dominant disorder in the absence of a known genetic syndrome. METHODS: We investigated a family with 26 members in whom ascending aortic aneurysms and acute type-A aortic dissections occurred over three generations. Examinations were performed to identify family members at specific risk. RESULTS: Six members presented with acute type-A aortic dissections and three relatives had ascending aortic aneurysms. Clinical examinations showed no characteristics of a known genetic syndrome. Molecular genetic analysis revealed no mutations known to cause a form of autosomal-dominant inherited aortic disease. CONCLUSION: Adequate diagnostic measures are mandatory in families with ascending aortic aneurysms or type-A aortic dissections to identify or exclude family members at risk for aortic diseases. Even in the absence of identifiable mutations causing isolated aortic aneurysms or aortic dissections, we recommend standardised examinations of all first-degree relatives of affected families. An indication for prophylactic aortic root replacement should be considered for patients at risk.