Background—: Right heart catheterization is the gold standard for assessment of pulmonary hemodynamics in patients with chronic thromboembolic pulmonary hypertension. To date, MRI has not been able to produce precise measurements of mean pulmonary arterial pressure (mPAP). The purpose of the study was to create a model for estimating mPAP and pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension by high temporal resolution phase-contrast MRI (PC-MRI) and to correlate the results with simultaneously acquired, invasive catheter-based measurements (simultaneously measured mPAP) and with right heart catheterization measurements. Methods and Results—: A total of 19 patients with chronic thromboembolic pulmonary hypertension underwent right heart catheterization and—after digital subtraction angiography of the pulmonary arteries—subsequent PC-MRI at 1.5 T with simultaneous recording of mPAP. Velocity– and flow–time curves of PC-MRI were used to calculate absolute acceleration time (Ata), maximum of mean velocities (MV), volume of acceleration (AV), and maximum flow acceleration (dQ/dt). On the basis of these parameters, multiple linear regression analysis revealed maximum achievable model fit (B=0.902) for the following linear combination equation to calculate mPAP (mPAP_cal): mPAP_cal=69.446−(0.521×Ata)−(0.570×MV)+(1.507×AV)+(0.002×dQ/dt). There was a statistically significant equivalence of mPAP_cal and simultaneously measured mPAP with a goodness of fit of 0.892. Pulmonary vascular resistance was overestimated by calculated pulmonary vascular resistance on the basis of PC-MRI in comparison with right heart catheterization–based measurements by a median of −112 dyn·s·cm ⁻⁵ , the pairwise regression formula revealed a goodness of fit of 0.792. Conclusions—: PC-MRI–derived parameters enable noninvasive assessment of pulmonary hemodynamics in patients with chronic thromboembolic pulmonary hypertension.

To assess the diagnostic value of cardiac MRI (CMR) in patients with acute chest pain, elevated cardiac enzymes and a negative coronary angiogram. This study included a total of 125 patients treated in the chest pain unit during a 39-month period. Each included patient underwent MRI within a median of 3 days after cardiac catheterization. The MRI protocol comprised cine, oedema-sensitive and late gadolinium-enhancement imaging. The standard of reference was a consensus diagnosis based on clinical follow-up and the synopsis of all clinical, laboratory and imaging data. MRI revealed a multitude of diagnoses, including ischaemic cardiomyopathy (CM), dilated CM, myocarditis, Takotsubo CM, hypertensive heart disease, hypertrophic CM, cardiac amyloidosis and non-compaction CM. MRI-based diagnoses were the same as the final reference diagnoses in 113/125 patients (90%), with the two diagnoses differing in only 12/125 patients. In two patients, no final diagnosis could be established. CMR performed early after the onset of symptoms revealed a broad spectrum of diseases. CMR delivered a correct final diagnosis in 90% of patients with acute chest pain, elevated cardiac enzymes and a negative coronary angiogram. Diagnosing patients with acute coronary syndrome but unobstructed coronary arteries remains a challenge for cardiologists. CMR performed early after catheterization reveals a broad spectrum of diseases with only a simple and quick examination protocol, and there is a high concordance between MRI-based diagnoses and final reference diagnoses.

Chronic thromboembolic pulmonary hypertension (CTEPH) can be defined as pulmonary hypertension (resting mean pulmonary arterial pressure of 25 mm Hg or more determined at right heart catheterization) with persistent pulmonary perfusion defects. It is a rare, but underdiagnosed disease with estimated incidences ranging from 0.5 % to 3.8 % of patients after an acute pulmonary embolism (PE), and in up to 10 % of those with a history of recurrent PE. CTEPH is the only form of pulmonary hypertension that can be surgically treated leading to normalization of pulmonary hemodynamics and exercise capacity in the vast majority of patients. The challenges for imaging in patients with suspected CTEPH are fourfold: the imaging modality should have a high diagnostic accuracy with regard to the presence of CTEPH and allow for differential diagnosis. It should enable detection of patients suitable for PEA with great certainty, and allow for quantification of PH by measuring pulmonary hemodynamics (mPAP and PVR), and finally, it can be used for therapy monitoring. This overview tries to elucidate the potential role of ECG-gated multidetector CT pulmonary angiography (MD-CTPA) and MR imaging, and summarizes the most important results that have been achieved so far. Generally speaking, ECG-gated MD-CTPA is superior to MR in the assessment of parenchymal and vascular pathologies of the lung, and allows for the assessment of cardiac structures. The implementation of iodine maps as a surrogate for lung perfusion enables functional assessment of lung perfusion by CT. MR imaging is the reference standard for the assessment of right heart function and lung perfusion, the latter delineating typical wedge-shaped perfusion defects in patients with CTEPH. New developments show that with MR techniques, an estimation of hemodynamic parameters like mean pulmonary arterial pressure and pulmonary vascular resistance will be possible. CT and MR imaging should be considered as complementary investigations providing comprehensive information in patients with CTEPH. Citation Format: • Wirth G, Brüggemann K, Bostel T et al. Chronic Thromboembolic Pulmonary Hypertension (CTEPH) – Potential Role of Multidetector-Row CT (MD-CT) and MR Imaging in the Diagnosis and Differential Diagnosis of the Disease. Fortschr Röntgenstr 2014; 186: 751 – 761 Die chronisch-thromboembolische pulmonale Hypertonie (CTEPH) kann als pulmonalarterielle Hypertonie (mittlerer pulmonalarterieller Ruhedruck > 25 mm Hg, bestimmt im Rahmen einer Rechtsherzkatheteruntersuchung) mit persistierenden Perfusionsdefekten nach einer einmaligen oder wiederholten Lungenembolie definiert werden. Es handelt sich um eine seltene, aber eher unterdiagnostizierte Erkrankung, deren Inzidenz zwischen 0,5 und 3,8 % nach einer akuten, und bis zu 10 % nach wiederholten Lungenembolien geschätzt wird. Die CTEPH ist die einzige chirurgisch therapierbare Form einer pulmonalen Hypertonie; durch eine erfolgreiche Operation kommt es zur Normalisierung der pulmonalen Hämodynamik und der körperlichen Belastbarkeit. Die Herausforderungen für die Bildgebung bei Patienten mit vermuteter CTEPH sind: hohe diagnostische Genauigkeit bezüglich dem Nachweis einer CTEPH und ihrer differentialdiagnostischen Abgrenzung, Erkennung chirurgisch therapierbarer Patienten, sichere Bestimmung der pulmonalen Hämodynamik (mittlerer pulmonalarterieller Druck und Lungengefäßwiderstand) und Eignung zur Therapieverlaufskontrolle. Diese Übersicht versucht, die potenzielle Rolle der EKG-getriggerten Mehrschicht-CT und der MRT in der Diagnostik der CTEPH zu beleuchten, und fasst die bis dahin erzielten Resultate zusammen. Allgemein zeichnen sich Vorteile für die MS-CT hinsichtlich der Detektion vaskulärer und parenchymatöser Veränderungen ab; mit EKG-Triggerung ermöglicht sie auch eine Beurteilung der kardialen Strukturen. Die Implementierung der Dual-Energy-Technik ermöglicht ein Jod-Mapping des Lungenparenchyms und damit eine Beurteilung der Lungenperfusion. Die MRT gilt nach wie vor als Referenzverfahren für die Beurteilung von Herzfunktion und Lungenperfusion. Neuere Entwicklungen zeigen, dass das Verfahren auch eine Abschätzung der pulmonalen Hämodynamik ermöglicht. Aktuell können MS-CT und MRT als komplementäre Untersuchungsverfahren angesehen werden, die umfassende Informationen bei Patienten mit vermuteter CTEPH ermöglichen. ¹ dedicated to Prof. Hans Schild on the occasion of his 60^th anniversary and one of my most important teachers of radiology. K-FK

Arterial hyperenhancement and washout on computed tomography and magnetic resonance imaging (MRI) are described by all major guidelines as specific criteria for non-invasive diagnosis of hepatocellular carcinoma (HCC). However, publications on the quantitative assessment of washout in MRI are lacking. Therefore, we evaluated a method for quantitatively measuring and defining washout in MRI in order to determine a cutoff value that allows objective HCC diagnosis. We analyzed all patients who underwent liver transplantation for cirrhosis or liver resection for HCC at our institution between 2003 and 2014. Washout was quantitatively investigated by placing a 25-mm2 region of interest (ROI) over each nodule and two 25-mm2 ROIs over adjacent liver parenchyma. The percentage signal ratio (PSR = 100 × ratio of signal intensity of adjacent liver to that of the lesion) was calculated for each series in both groups. Accordingly, this quantitative measurement was compared to a qualitative approach. A total of 16 hypervascularized non-HCC nodules and 69 HCC nodules were identified. Interobserver reliability was reasonably good for the measurement of PSRs and readers showed a substantial agreement for the qualitative assessment. In the HCC group, the median PSR was 116.2 at equilibrium and 112.9 in the delayed phase. In the non-HCC group, the median PSR was 93.8 at equilibrium and 96.0 in the delayed phase. Receiver operating characteristic analysis indicated areas under the curve of 0.902 (p < 0.001) and 0.873 (p < 0.001) at equilibrium and in the delayed phase. PSR values of 102 at equilibrium and 101.5 in the delayed phase led to the highest Youden’s index of 0.82 and 0.77, respectively. These PSR cutoffs yielded sensitivities of 82 and 77 %, respectively, with specificities of 100 %. The sensitivity for the qualitative assessment of washout was 88 and 93 % and the specificity was 48 and 56 %. For the classification of HCC, sensitivity yielded 95 and 97 % and specificity was 68 and 56 %, respectively. Quantitatively measuring HCC washout in MRI is easy and reproducible. It can objectify and support diagnosis of HCC. However, the quantitative measurement of washout can only serve as one of several components of HCC assessment.

MRI T2 mapping has been proven to be sensitive to the level of blood oxygenation. We hypothesized that impaired exercise capacity in chronic heart failure is associated with a greater difference between right (RV) to left ventricular (LV) blood pool T2 relaxation times due to a higher level of peripheral blood desaturation, compared to patients with preserved exercise capacity and to healthy controls. Patients with chronic heart failure (n = 70) who had undergone both cardiac MRI (CMR) and a 6-min walk test (6MWT) were retrospectively identified. Propensity score matched healthy individuals (n = 35) served as control group. CMR analyses included cine acquisitions and T2 mapping to obtain blood pool T2 relaxation times of the RV and LV. Following common practice, age- and gender-adjusted nominal distances and respective percentiles were calculated for the 6MWT. The relationship between the RV/LV T2 blood pool ratio and the results from 6MWT were evaluated by Spearman’s correlation coefficients and regression analyses. Inter-group differences were assessed by independent t-tests and univariate analysis of variance. The RV/LV T2 ratio moderately correlated with the percentiles of nominal distances in the 6MWT (r = 0.66) while ejection fraction, end-diastolic and end-systolic volumes showed no correlation (r = 0.09, 0.07 and − 0.01, respectively). In addition, there were significant differences in the RV/LV T2 ratio between patients with and without significant post-exercise dyspnea (p = 0.001). Regression analyses showed that RV/LV T2 ratio was an independent predictor of the distance walked and the presence of post-exercise dyspnea (p < 0.001). The proposed RV/LV T2 ratio, obtained by two simple measurements on a routinely acquired four-chamber T2 map, was superior to established parameters of cardiac function to predict exercise capacity and the presence of post-exercise dyspnea in patients with chronic heart failure.

Purpose The usefulness of direct MR arthrography of the shoulder with additional ABER position (ABER-MRA) has always been discussed. The goals of the following review are to analyze the usefulness of this technique according to the available literature and present recommendations with respect to indications and benefits in diagnostic imaging of shoulder abnormalities in the clinical routine. Method For this review we assessed the current literature databases of the Cochrane Library, Embase, and PubMed with regard to MRA in the ABER position up to the February 28, 2022. Search terms were “shoulder MRA, ABER”, “MRI ABER”, “MR ABER”, “shoulder, abduction external rotation MRA”, “abduction external rotation MRI” and “ABER position”. The inclusion criteria were prospective and retrospective studies with surgical and/or arthroscopic correlation within 12 months. Overall, 16 studies with 724 patients fulfilled the inclusion criteria: 10 studies dealing with anterior instabilities, three studies with posterior instabilities and seven studies with suspected rotator cuff pathologies (some studies addressing multiple items). Results For anterior instability the use of ABER-MRA in the ABER position led to a significant increase in sensitivity for detecting lesions of the labral ligamentous complex compared with standard 3-plane shoulder MRA (81 % versus 92 %, p = 0.001) while maintaining high specificity (96 %). ABER-MRA demonstrated high sensitivity and specificity (89 % and 100 %, respectively) for SLAP lesions and was able to detect micro-instability in overhead athletes, but case counts are still very small. With regard to rotator cuff tears, no improvement of sensitivity or specificity could be shown with use of ABER-MRA. Conclusion Based on the currently available literature, ABER-MRA achieves a level of evidence C in the detection of pathologies of the anteroinferior labroligamentous complex. With regard to the evaluation of SLAP lesions and the exact determination of the degree of rotator cuff injury, ABER-MRA can be of additive value, but is still a case-by-case decision. Key Points: Citation Format