CT-derived lung vessel morphology correlates with prognostic markers in precapillary pulmonary hypertension.

BACKGROUND: While computed tomography pulmonary angiography (CTPA) is an integral part of the work-up in patients with suspected pulmonary hypertension (PH), there is no established CTPA-derived prognostic marker. We aimed to assess whether quantitative readouts of lung vessel morphology correlate with established prognostic indicators in PH. METHODS: We applied a fully-automatic in-house developed algorithm for segmentation of arteries and veins to determine lung vessel morphology in patients with precapillary PH who underwent right heart catheterization and CTPA between May 2016 and May 2019. Primary endpoint of this retrospective study was the calculation of receiver operating characteristics for identifying low and high mortality risk according to the 3-strata risk assessment model presented in the current guidelines. RESULTS: We analyzed 73 patients, median age 65 years (interquartile range (IQR): 54-76), female/male ratio 35/38, median mean pulmonary arterial pressure 37 mm Hg (IQR: 30-46), and found significant correlations with important prognostic factors in pulmonary arterial hypertension. N-terminal pro-brain natriuretic peptide, cardiac index, mixed venous oxygen saturation, and 6-minute walking distance were correlated with the ratio of the number of arteries over veins with vessel diameters of 6-10 mm (Spearman correlation coefficients ρ = 0.64, p < 0.001; ρ = -0.60, p < 0.001; ρ = -0.47, p = 0.005; ρ = -0.45, p = 0.001, respectively). This ratio predicted a low- and high-risk score with an area under the curve of 0.73 (95% confidence interval (CI): 0.56-0.90) and 0.86 (95% CI: 0.74-0.97), respectively. CONCLUSIONS: The ratio of the number of arteries over veins with diameters between 6 and 10 mm is significantly correlated with prognostic markers in pulmonary hypertension and predicts low and high mortality risk.

Thoracic aorta diameters in Marfan patients: Intraindividual comparison of 3D modified relaxation-enhanced angiography without contrast and triggering (REACT) with transthoracic echocardiography.

OBJECTIVE: To compare the measurement of aortic diameters using a novel flow-independent MR-Angiography (3D modified Relaxation-Enhanced Angiography without Contrast and Triggering (modified REACT)) and transthoracic echocardiography (TTE) in Marfan syndrome (MFS) patients. MATERIAL AND METHODS: This retrospective, single-center analysis included 46 examinations of 32 MFS patients (mean age 37.5 ± 11.3 years, 17 women, no prior aortic surgery) who received TTE and 3D modified REACT (ECG- and respiratory-triggering, Compressed SENSE factor 9 for acceleration of image acquisition) of the thoracic aorta. Aortic diameters (sinus of Valsalva (SV), sinotubular junction (STJ), and ascending aorta (AoA)) were independently measured by two cardiologists in TTE (leading-edge) and two radiologists in modified REACT (inner-edge, using multiplanar reconstruction). Intraclass correlation coefficient, Bland-Altman analyses, and Pearson's correlation (r) were used to assess agreement between observers and methods. RESULTS: Interobserver correlation at the SV, STJ, and AoA were excellent for both, TTE (ICC = 0.95-0.98) and modified REACT (ICC = 0.99-1.00). There was no significant difference between TTE and modified REACT for diameters measured at the SV (39.24 ± 3.24 mm vs. 39.63 ± 3.76 mm; p = 0.26; r = 0.78) and the STJ (35.16 ± 4.47 mm vs. 35.37 ± 4.74 mm; p = 0.552; r = 0.87). AoA diameters determined by TTE were larger than in modified REACT (34.29 ± 5.31 mm vs. 30.65 ± 5.64 mm; p < 0.01; r = 0.74). The mean scan time of modified REACT was 05:06 min ± 02:47 min, depending on the patient's breathing frequency and heart rate. CONCLUSIONS: Both TTE and modified REACT showed a strong correlation for all aortic levels; however, at the AoA, diameters were larger using TTE, mostly due to the limited field of view of the latter with measurements being closer to the aortic valve. Given the excellent interobserver correlation and the strong agreement with TTE, modified REACT represents an attractive method to depict the thoracic aorta in MFS patients.

Favorable Remodeling After TEVAR in Uncomplicated Acute and Subacute Type B Aortic Dissection in Comparison to Conservative Treatment: A Midterm Analysis.

PURPOSE: The purpose of the study was to evaluate the midterm and long-term outcomes of patients who underwent thoracic endovascular aortic repair (TEVAR) procedure to treat an uncomplicated acute and subacute type B aortic dissection (uATBAD) with high risk for subsequent aortic complications compared with the group of patients who received a conservative treatment protocol during the same period. MATERIALS AND METHODS: Between 2008 and 2019, 35 patients who had TEVAR due to uATBAD and those with conservative procedure (n=18) were included in a retrospective analysis and follow-up study. The primary endpoints were false lumen thrombosis/perfusion, true lumen diameter, and aortic dilatation. The aortic-related mortality, reintervention, and long-term survival were the secondary endpoints. RESULTS: In the study period, 53 patients (22 females) with a mean age of 61.1±13 years were included. No 30-day and in-hospital mortality was recorded. Permanent neurological deficits occurred in 2 patients (5.7%). In the TEVAR group (n=35) and in a median follow-up period of 34 months, a significant reduction of maximum aortic and false lumen diameter as well as a significant increase of true lumen diameter were detected (p<0.001 each). Complete false lumen thrombosis increased from 6% preoperatively to 60% at follow-up. The median difference in aortic, false lumen, and true lumen diameter was -5 mm (interquartile range [IQR]=-28 to 8 mm), -11 mm (IQR=-53 to 10 mm), and 7 mm (IQR=-13 to 17 mm), respectively. In 3 patients (8.6%), a reintervention was needed. Two patients (1 aortic-related) died during follow-up. The estimated survival according to Kaplan-Meyer analysis was 94.1% after 3 years and 87.5% after 5 years. Similar to the TEVAR group, no 30-day or in-hospital mortality was recorded in the conservative group. During follow-up, 2 patients died and 5 patients underwent conversion-TEVAR (28%). In a median follow-up period of 26 months (range=150), a significant increase of maximum aortic diameter (p=0.006) and a tendency to augmentation of the false lumen (p=0.06) were noted. No significant reduction of the true lumen was seen. CONCLUSIONS: Thoracic endovascular aortic repair in patients at high risk of subsequent aortic complications in uncomplicated acute and subacute type B aortic dissection is safe and is associated with favorable midterm outcomes regarding aortic remodeling. CLINICAL IMPACT: In a retrospective, single center analysis of prospectively collected data with follow-up, we compared 35 patients with high-risk features who recieved TEVAR in acute and sub-acute uncomplicated type B aortic dissection to a control-group (n=18). The TEVAR group showed a significant positive remoduling (reduction of max. aortic and false lumen diameter and increase of true lumen diameter (p<0.001 each)) during follow-up with an estimated survival of 94.1% after 3 years and 87.5% after 5 years.

Risk of persistent air leaks following percutaneous cryoablation and microwave ablation of peripheral lung tumors.

OBJECTIVES: To compare the incidence of persistent air leak (PAL) following cryoablation vs MWA of lung tumors when the ablation zone includes the pleura. METHODS: This bi-institutional retrospective cohort study evaluated consecutive peripheral lung tumors treated with cryoablation or MWA from 2006 to 2021. PAL was defined as an air leak for more than 24 h after chest tube placement or an enlarging postprocedural pneumothorax requiring chest tube placement. The pleural area included by the ablation zone was quantified on CT using semi-automated segmentation. PAL incidence was compared between ablation modalities and a parsimonious multivariable model was developed to assess the odds of PAL using generalized estimating equations and purposeful selection of predefined covariates. Time-to-local tumor progression (LTP) was compared between ablation modalities using Fine-Gray models, with death as a competing risk. RESULTS: In total, 260 tumors (mean diameter, 13.1 mm ± 7.4; mean distance to pleura, 3.6 mm ± 5.2) in 116 patients (mean age, 61.1 years ± 15.3; 60 women) and 173 sessions (112 cryoablations, 61 MWA) were included. PAL occurred after 25/173 (15%) sessions. The incidence was significantly lower following cryoablation compared to MWA (10 [9%] vs 15 [25%]; p = .006). The odds of PAL adjusted for the number of treated tumors per session were 67% lower following cryoablation (odds ratio = 0.33 [95% CI, 0.14-0.82]; p = .02) vs MWA. There was no significant difference in time-to-LTP between ablation modalities (p = .36). CONCLUSIONS: Cryoablation of peripheral lung tumors bears a lower risk of PAL compared to MWA when the ablation zone includes the pleura, without adversely affecting time-to-LTP. KEY POINTS: • The incidence of persistent air leaks after percutaneous ablation of peripheral lung tumors was lower following cryoablation compared to microwave ablation (9% vs 25%; p = .006). • The mean chest tube dwell time was 54% shorter following cryoablation compared to MWA (p = .04). • Local tumor progression did not differ between lung tumors treated with percutaneous cryoablation compared to microwave ablation (p = .36).

Preexisting Chronic Thromboembolic Pulmonary Hypertension in Acute Pulmonary Embolism.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is considered a complication of pulmonary embolism (PE). However, signs of CTEPH may exist in patients with a first symptomatic PE. RESEARCH QUESTION: Which radiologic findings on CT pulmonary angiography (CTPA) at the time of acute PE could indicate the presence of preexisting CTEPH? STUDY DESIGN AND METHODS: This study included unselected patients with acute PE who were prospectively followed up for 2 years with a structured visit schedule. Two expert radiologists independently assessed patients' baseline CTPAs for preexisting CTEPH; in case of disagreement, a decision was reached by a 2:1 majority with a third expert radiologist. In addition, the radiologists checked for predefined individual parameters suggesting chronic PE and pulmonary hypertension. RESULTS: Signs of chronic PE or CTEPH at baseline were identified in 46 of 303 included patients (15%). Intravascular webs, arterial narrowing or retraction, dilated bronchial arteries, and right ventricular hypertrophy were the main drivers of the assessment. Five (1.7%) patients were diagnosed with CTEPH during follow-up. All four patients diagnosed with CTEPH early (83-108 days following acute PE) were found in enriched subgroups based on the experts' overall assessment or fulfilling a minimum number of the predefined radiologic criteria at baseline. The specificity of preexisting CTEPH diagnosis and the level of radiologists' agreement improved as the number of required criteria increased. INTERPRETATION: Searching for predefined radiologic parameters suggesting preexisting CTEPH at the time of acute PE diagnosis may allow for targeted follow-up strategies and risk-adapted CTEPH screening, thus facilitating earlier CTEPH diagnosis.

Transjugular intrahepatic portosystemic shunt, local thrombaspiration, and lysis for management of fulminant portomesenteric thrombosis and atraumatic splenic rupture due to vector-vaccine-induced thrombotic thrombocytopenia: a case report.

INTRODUCTION: Recombinant adenoviral vector vaccines against severe acute respiratory syndrome coronavirus 2 have been observed to be associated with vaccine-induced immune thrombotic thrombocytopenia. Though vaccine-induced immune thrombotic thrombocytopenia is a rare complication after vaccination with recombinant adenoviral vector vaccines, it can lead to severe complications. In vaccine-induced immune thrombotic thrombocytopenia, the vector vaccine induces heparin-independent production of platelet factor 4 autoantibodies, resulting in platelet activation and aggregation. Therefore, patients suffering from vaccine-induced immune thrombotic thrombocytopenia particularly present with signs of arterial or venous thrombosis, often at atypical sites, but also signs of bleeding due to disseminated intravascular coagulation and severe thrombocytopenia. We describe herein a rare case of fulminant portomesenteric thrombosis and atraumatic splenic rupture due to vaccine-induced immune thrombotic thrombocytopenia. This case report presents the diagnosis and treatment of a healthy 29-year-old male Caucasian patient suffering from an extended portomesenteric thrombosis associated with atraumatic splenic rupture due to vaccine-induced immune thrombotic thrombocytopenia after the first dose of an adenoviral vector vaccine against severe acute respiratory syndrome coronavirus 2 [ChAdOx1 nCoV-19 (AZD1222)]. Therapeutic management of vaccine-induced immune thrombotic thrombocytopenia initially focused on systemic anticoagulation avoiding heparin and the application of steroids and intravenous immune globulins as per the recommendations of international societies of hematology and hemostaseology. Owing to the atraumatic splenic rupture and extended portomesenteric thrombosis, successful management of this case required splenectomy with additional placement of a transjugular intrahepatic portosystemic shunt to perform local thrombaspiration, plus repeated local lysis to reconstitute hepatopetal blood flow. CONCLUSION: The complexity and wide spectrum of the clinical picture in patients suffering from vaccine-induced immune thrombotic thrombocytopenia demand an early interdisciplinary diagnostic and therapeutic approach. Severe cases of portomesenteric thrombosis in vaccine-induced immune thrombotic thrombocytopenia, refractory to conservative management, may require additional placement of a transjugular intrahepatic portosystemic shunt, thrombaspiration, thrombolysis, and surgical intervention for effective management.

Detection of patients with chronic thromboembolic pulmonary hypertension by volumetric iodine quantification in the lung-a case control study.

BACKGROUND: To evaluate whether volumetric iodine quantification of the lung allows for the automatic identification of patients with chronic thromboembolic pulmonary hypertension (CTEPH) and whether the extent of pulmonary malperfusion correlates with invasive hemodynamic parameters. METHODS: Retrospective data base search identified 30 consecutive patients with CTEPH who underwent CT pulmonary angiography (CTPA) on a spectral-detector CT scanner. Thirty consecutive patients who underwent an identical CT examination for evaluation of suspected acute pulmonary embolism and had no signs of pulmonary embolism or PH, served as control cohort. Lungs were automatically segmented for all patients and normal and malperfused volumes were segmented based on iodine density thresholds. Results were compared between groups. For correlation analysis between the extent of malperfused volume and mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) 3 patients were excluded because of a time span of more than 30 days between CTPA and right heart catheterization. RESULTS: Patients with CTEPH had a higher percentage of malperfused lung compared to controls (43.25%±24.72% vs. 21.82%±20.72%; P=0.001) and showed reduced mean iodine density in malperfused and normal-perfused lung areas, as well as in the vessel volume. Controls showed a left-tailed distribution of iodine density in malperfused lung areas while patients with CTEPH had a more symmetrical distribution (Skew: -0.382±0.435 vs. -0.010±0.396; P=0.004). Patients with CTEPH showed a significant correlation between the percentage of malperfused lung volume and the PVR (r=0.57, P=0.001). CONCLUSIONS: Volumetric iodine quantification helps to identify patients with CTEPH by showing increased areas of malperfusion. The extent of malperfusion might provide a measurement for disease severity in patients with CTEPH.

Advanced Deep Learning Approach to Automatically Segment Malignant Tumors and Ablation Zone in the Liver With Contrast-Enhanced CT.

OBJECTIVE: Liver cancer is one of the most commonly diagnosed cancer, and energy-based tumor ablation is a widely accepted treatment. Automatic and robust segmentation of liver tumors and ablation zones would facilitate the evaluation of treatment success. The purpose of this study was to develop and evaluate an automatic deep learning based method for (1) segmentation of liver and liver tumors in both arterial and portal venous phase for pre-treatment CT, and (2) segmentation of liver and ablation zones in both arterial and portal venous phase for after ablation treatment. MATERIALS AND METHODS: 252 CT images from 63 patients undergoing liver tumor ablation at a large University Hospital were retrospectively included; each patient had pre-treatment and post-treatment multi-phase CT images. 3D voxel-wise manual segmentation of the liver, tumors and ablation region by the radiologist provided reference standard. Deep learning models for liver and lesion segmentation were initially trained on the public Liver Tumor Segmentation Challenge (LiTS) dataset to obtain base models. Then, transfer learning was applied to adapt the base models on the clinical training-set, to obtain tumor and ablation segmentation models both for arterial and portal venous phase images. For modeling, 2D residual-attention Unet (RA-Unet) was employed for liver segmentation and a multi-scale patch-based 3D RA-Unet for tumor and ablation segmentation. RESULTS: On the independent test-set, the proposed method achieved a dice similarity coefficient (DSC) of 0.96 and 0.95 for liver segmentation on arterial and portal venous phase, respectively. For liver tumors, the model on arterial phase achieved detection sensitivity of 71%, DSC of 0.64, and on portal venous phase sensitivity of 82%, DSC of 0.73. For liver tumors >0.5cm3 performance improved to sensitivity 79%, DSC 0.65 on arterial phase and, sensitivity 86%, DSC 0.72 on portal venous phase. For ablation zone, the model on arterial phase achieved detection sensitivity of 90%, DSC of 0.83, and on portal venous phase sensitivity of 90%, DSC of 0.89. CONCLUSION: The proposed deep learning approach can provide automated segmentation of liver tumors and ablation zones on multi-phase (arterial and portal venous) and multi-time-point (before and after treatment) CT enabling quantitative evaluation of treatment success.

In vitro evaluation of cerebrospinal fluid velocity measurement in type I Chiari malformation: repeatability, reproducibility, and agreement using 2D phase contrast and 4D flow MRI.

BACKGROUND: Phase contrast magnetic resonance imaging, PC MRI, is a valuable tool allowing for non-invasive quantification of CSF dynamics, but has lacked adoption in clinical practice for Chiari malformation diagnostics. To improve these diagnostic practices, a better understanding of PC MRI based measurement agreement, repeatability, and reproducibility of CSF dynamics is needed. METHODS: An anatomically realistic in vitro subject specific model of a Chiari malformation patient was scanned three times at five different scanning centers using 2D PC MRI and 4D Flow techniques to quantify intra-scanner repeatability, inter-scanner reproducibility, and agreement between imaging modalities. Peak systolic CSF velocities were measured at nine axial planes using 2D PC MRI, which were then compared to 4D Flow peak systolic velocity measurements extracted at those exact axial positions along the model. RESULTS: Comparison of measurement results showed good overall agreement of CSF velocity detection between 2D PC MRI and 4D Flow (p = 0.86), fair intra-scanner repeatability (confidence intervals ± 1.5 cm/s), and poor inter-scanner reproducibility. On average, 4D Flow measurements had a larger variability than 2D PC MRI measurements (standard deviations 1.83 and 1.04 cm/s, respectively). CONCLUSION: Agreement, repeatability, and reproducibility of 2D PC MRI and 4D Flow detection of peak CSF velocities was quantified using a patient-specific in vitro model of Chiari malformation. In combination, the greatest factor leading to measurement inconsistency was determined to be a lack of reproducibility between different MRI centers. Overall, these findings may help lead to better understanding for application of 2D PC MRI and 4D Flow techniques as diagnostic tools for CSF dynamics quantification in Chiari malformation and related diseases.

Outcomes Following Percutaneous Microwave and Cryoablation of Lung Metastases from Adenoid Cystic Carcinoma of the Head and Neck: A Bi-Institutional Retrospective Cohort Study.

OBECTIVE: The aim of this study was to report outcomes following percutaneous microwave and cryoablation of lung metastases from adenoid cystic carcinoma (ACC) of the head and neck. MATERIAL AND METHODS: This bi-institutional retrospective cohort study included 10 patients (6 females, median age 59 years [range 28-81]) who underwent 32 percutaneous ablation sessions (21 cryoablation, 11 microwave) of 60 lung metastases (median 3.5 tumors per patient [range 1-16]) from 2007 to 2019. Median tumor diameter was 16 mm [range 7-40], significantly larger for cryoablation (22 mm, p = 0.002). A median of two tumors were treated per session [range 1-7]. Technical success, local control, complications, and overall survival were assessed. RESULTS: Primary technical success was achieved for 55/60 tumors (91.7%). Median follow-up was 40.6 months (clinical) and 32.5 months (imaging, per tumor). Local control at 1, 2, and 3 years was 94.7%, 80.8%, and 76.4%, respectively, and did not differ between ablation modalities. Five of fifteen recurrent tumors underwent repeat ablation, and secondary technical success was achieved in four (80%). Assisted local tumor control at 1, 2, and 3 years was 96.2%, 89.8%, and 84.9%, respectively. Complications occurred following 24/32 sessions (75.0%) and 57.2% Common Terminology Criteria for Adverse Events (CTCAE) lower than grade 3. Of 13 pneumothoraces, 7 required chest tube placements. Hemoptysis occurred after 7/21 cryoablation sessions, and bronchopleural fistula developed more frequently with microwave (p = 0.037). Median length of hospital stay was 1 day [range 0-10], and median overall survival was 81.5 months (IQR 40.4-93.1). CONCLUSION: Percutaneous computed tomography-guided microwave and cryoablation can treat lung metastases from ACC of the head and neck. Complications are common but manageable, with full recovery expected.

Cerebrospinal fluid pulse wave velocity measurements: In vitro and in vivo evaluation of a novel multiband cine phase-contrast MRI sequence.

PURPOSE: Intracranial and intraspinal compliance are parameters of interest in the diagnosis and prediction of treatment outcome in patients with normal pressure hydrocephalus and other forms of communicating hydrocephalus. A noninvasive method to estimate the spinal cerebrospinal fluid (CSF) pulse wave velocity (PWV) as a measure of compliance was developed using a multiband cine phase-contrast MRI sequence and a foot-to-foot algorithm. METHODS: We used computational simulations to estimate the accuracy of the MRI acquisition and transit-time algorithm. In vitro measurements were performed to investigate the reproducibility and accuracy of the measurements under controlled conditions. In vivo measurements in 20 healthy subjects and 2 patients with normal pressure hydrocephalus were acquired to show the technical feasibility in a clinical setting. RESULTS: Simulations showed a mean deviation of the calculated CSF PWV of 3.41% ± 2.68%. In vitro results were in line with theory, showing a square-root relation between PWV and transmural pressure and a good reproducibility with SDs of repeated measurements below 5%. Mean CSF PWV over all healthy subjects was 5.83 ± 3.36 m/s. The CSF PWV measurements in the patients with normal pressure hydrocephalus were distinctly higher before CSF shunt surgery (33.80 ± 6.75 m/s and 31.31 ± 7.82 m/s), with a decrease 5 days after CSF shunt surgery (15.69 ± 3.37 m/s). CONCLUSION: This study evaluates the feasibility of CSF PWV measurements using a multiband cine phase-contrast MRI sequence. In vitro and in vivo measurements showed that this method is a potential tool for the noninvasive estimation of intraspinal compliance.

Compressed-sensing accelerated 4D flow MRI of cerebrospinal fluid dynamics.

BACKGROUND: 4D flow magnetic resonance imaging (MRI) of CSF can make an important contribution to the understanding of hydrodynamic changes in various neurological diseases but remains limited in clinical application due to long acquisition times. The aim of this study was to evaluate the accuracy of compressed SENSE accelerated MRI measurements of the spinal CSF flow. METHODS: In 20 healthy subjects 4D flow MRI of the CSF in the cervical spine was acquired using compressed sensitivity encoding [CSE, a combination of compressed sensing and parallel imaging (SENSE) provided by the manufacturer] with acceleration factors between 4 and 10. A conventional scan using SENSE was used as reference. Extracted parameters were peak velocity, absolute net flow, forward flow and backward flow. Bland-Altman analysis was performed to determine the scan-rescan reproducibility and the agreement between SENSE and compressed SENSE. Additionally, a time accumulated flow error was calculated. In one additional subject flow of the spinal canal at the level of the entire spinal cord was assessed. RESULTS: Averaged acquisition times were 10:21 min (SENSE), 9:31 min (CSE4), 6:25 min (CSE6), 4:53 min (CSE8) and 3:51 min (CSE10). Acquisition of the CSF flow surrounding the entire spinal cord took 14:40 min. Bland-Altman analysis showed good agreement for peak velocity, but slight overestimations for absolute net flow, forward flow and backward flow (< 1 ml/min) in CSE4-8. Results of the accumulated flow error were similar for CSE4 to CSE8. CONCLUSION: A quantitative analysis of acceleration factors CSE4-10 showed that CSE with an acceleration factor up to 6 is feasible. This allows a scan time reduction of 40% and enables the acquisition and analysis of the CSF flow dynamics surrounding the entire spinal cord within a clinically acceptable scan time.

Evaluation of soft-plaque stenoses in coronary artery stents using conventional and monoenergetic images: first in-vitro experience and comparison of two different dual-energy techniques.

BACKGROUND: Non-invasive coronary imaging after stent placement remains challenging. Favorable results for dual-energy computed tomography (DECT) derived monoenergetic (MonoE) images have been reported for this purpose. Nowadays, there are different dual-energy techniques available, each with specific advantages and disadvantages. However, for the evaluation of coronaries after stent implantation there is no systematic comparison between different dual-energy techniques. Therefore, the aim of our study was to compare two widely used DECT systems using an in-stent restenosis (ISR) phantom setup. METHODS: Soft-plaque-like stenoses (~50% of lumen) were inserted into ten coronary stents embedded in contrast-filled vessel phantoms. A dual-source CT (DSCT) and a dual-layer CT (DLCT) with comparable acquisition and reconstruction parameters were used. Conventional polyenergetic (PolyE) and MonoE images with 9 different levels (40-120 keV) were calculated. ISR assessability was evaluated by subjective scoring using a 5-point scale and by the following quantitative parameters: image noise, visible lumen diameter (VLD) and ISR contrast-to-noise ratio (CNR). RESULTS: A non-significant trend towards larger VLD in DLCT images was observed. Highest noise was found in low-keV MonoE with significantly higher values for DSCT than for DLCT. Conversely, noise was significantly lower for DSCT at higher-keV MonoE. Peak ISR CNR values were found at low-keV MonoE with no significant difference between both systems. However, for PolyE and mid-energy MonoE, CNRs were significantly higher for DSCT. Subjective image quality was significantly better for PolyE and low-keV MonoE than for high-keV MonoE, also without significant difference between both systems. CONCLUSIONS: Conspicuity of ISR benefits from DECT. Peak CNRs were comparable for both DECT systems and low-keV MonoE offered the highest CNR values and best subjective image quality. In contrast, high-keV MonoE cannot be recommended for stent evaluation due to poor CNR values and therefore significantly limited visualization of stenoses.

Precision, reproducibility and applicability of an undersampled multi-venc 4D flow MRI sequence for the assessment of cardiac hemodynamics.

BACKGROUND AND PURPOSE: For the assessment of cardiovascular blood flow, 2D flow (2D) and 4D flow with a single venc (4D Mono) are established techniques. The objective of this study was to validate a multi-venc 4D flow (4D Multi) sequence for the improved simultaneous assessment of arterial and venous flow in high and low flow conditions and to investigate the scan-rescan reproducibility and inter-observer variability of the novel sequence. METHODS: Eleven volunteers with no known heart condition (female: 6, mean age: 25.8 ±â€¯9.1 years) and two patients with a Fontan circulation were examined using phase-contrast 2D and 4D flow MRI. Stroke volumes, maximum velocities, net flow curves and internal consistency were measured and compared between 2D, 4D Mono and 4D Multi. Additionally, scan-rescan and inter-observer variabilities were analyzed. Finally, qualitative visualization comparisons were performed. RESULTS: Bland-Altman analysis show a higher agreement in stroke volumes between 4D Multi and 2D (7 ±â€¯11%) than 4D Mono and 2D (11 ±â€¯24%). 4D Multi is more accurate than 4D Mono in measuring time-resolved net flow throughout the cardiac cycle and qualitative blood flow visualization of 4D Multi is more accurate in visualizing flow patterns revealing more details and less artifacts than 4D Mono. Scan-rescan reproducibility is higher in 4D Multi (-0.04 ±â€¯4.5 ml) than 2D (2.1 ±â€¯7.3 ml) and inter-observer variability is low in both techniques (2D: -0.4 ±â€¯3.4 ml and 4D Multi: 0.4 ±â€¯3.5 ml). Internal consistency was improved in volunteers and patients when using 4D Multi as compared to 4D Mono. CONCLUSION: 4D Multi offers a comprehensive way to accurately quantify flow in arteries and veins both in high and low flow situations and to visualize detailed flow patterns. This technique is readily applicable in the clinical setting and has the potential to be beneficial in the clinical assessment of valvular and congenital heart diseases.

Prominent right ventricular mass in a young patient with a history of classic testicular seminoma: a case report.

BACKGROUND: The incidence of intracardiac masses is generally low. In most cases, the formation of a thrombus represents the principal diagnosis in clinical practice. The differential diagnosis mainly includes primary tumours of the heart as well as intracardiac metastases. Testicular cancer is a rare malignancy, accounting for approximately 1% of all male tumours. Cardiac metastasis of a seminoma is extremely rare. CASE SUMMARY: A 30-year-old man with a history of a classic seminoma of the right testis was referred to our university hospital from an outside clinic. Transthoracic echocardiography showed a large space-occupying mass in the right ventricle (4.0 cm × 4.5 cm × 5.5 cm) attached to the apex and septum. Cardiac magnetic resonance imaging confirmed the finding of a 5.5 cm × 3.5 cm lesion without freely movable appendage or obstruction of the right ventricular outflow tract. Tissue characterization by T1- and T2-weighted black blood imaging revealed a signal behaviour comparable to pulmonary metastases. Additionally, positron emission tomography (PET) with 250 MBq induced 18-fluorodeoxyglucose (18F-FDG) as part of a re-staging showed significant FDG-uptake. Thus, the final diagnosis of an intracardiac metastasis of the testicular seminoma was made, and the patient was treated with cisplatin, etoposide, and bleomycin chemotherapy according to the current guidelines. A repeat trans-thoracic echocardiogram (TTE) performed 2 weeks later already demonstrated a significant reduction of the metastasis with a diameter of 3.3 cm × 3.0 cm. DISCUSSION: In the past few years, multimodality imaging has become essential in the diagnostic evaluation of cardiac disease. In order to improve the diagnostic accuracy, a modern approach should preferably contain the integration of different imaging modalities. Cardiac magnetic resonance imaging as well as 18F-FDG-PET/computed tomography helped us reach the aetiological diagnosis of an intracardiac metastasis and to initiate prompt treatment.

Diagnosis of pulmonary hypertension using spectral-detector CT.

OBJECTIVES: To evaluate the value of spectral-detector CT (SDCT) in the diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH), its differentiation against other etiologies of pulmonary hypertension (PH) and in the prediction of disease severity. MATERIALS AND METHODS: 60 patients with suspected PH underwent SDCT. Additional diagnostic tests in accordance with the ESC guidelines including right heart catherization and VQ-SPECT were performed. After full diagnostic work-up patients were classified as: 21 precapillary PH, 5 postcapillary PH, 6 combined pre- and postcapillary PH, 19 CTEPH, 9 no PH. SDCT examinations were analyzed by two blinded readers deciding on the diagnosis of CTEPH and scoring the extent of perfusion abnormalities on iodine density images. An additional reading was performed using conventional CTPA images only. RESULTS: With access to SDCT data, both readers reached a sensitivity of 100% for the diagnosis of CTEPH with a specificity of 95.1% and 87.8%. On analysis of conventional CTPA images alone, specificity and diagnostic confidence decreased for both readers (Specificity 90.2 and 85.3%) while sensitivity dropped for the less experienced reader only (Sensitivity 78.9%). Patients with PH showed significantly more perfusion abnormalities than patients without PH (16.6 ±â€¯8.4 vs. 9.5 ±â€¯8.9 p < 0.001) and the extent of perfusion abnormalities correlated with the mean pulmonary artery pressure (r = 0.37 p = 0.008). CONCLUSIONS: SDCT offers confident identification of patients with CTEPH and enables a comprehensive analysis of pulmonary vasculature, pulmonary perfusion and the lung parenchyma in a single examination for patients with suspected PH.

Knowledge-based iterative reconstructions for imaging of coronary artery stents: first in-vitro experience and comparison of different radiation dose levels and kernel settings.

BACKGROUND: Advanced knowledge-based iterative model reconstructions (IMR) became recently available for routine computed tomography (CT). Using more realistic physical models it promises improved image quality and potential radiation dose reductions, both possibly beneficial for non-invasive assessment of coronary stents. PURPOSE: To evaluate the influence of different IMR settings at different radiation doses on stent lumen visualization in comparison to filtered back projection (FBP) and first-generation (hybrid) iterative reconstruction (HIR). MATERIAL AND METHODS: Ten coronary stents in a coronary phantom were examined at four different dose settings (120 kV/125 mAs, 120 kV/75 mAs, 100 kV/125 mAs, 100 kV/75 mAs). Images were reconstructed with stent-specific FBP and HIR kernels and with IMR using CardiacRoutine (CR) and CardiacSharp (CS) settings at three different iteration levels. Image quality was evaluated using established parameters: image noise; in-stent attenuation difference; and visible lumen diameter. RESULTS: Image noise was significantly lower in IMR than in corresponding HIR and FBP images. At lower radiation doses, image noise increased significantly except with IMR CR3 and IMR CS3. Visible lumen diameters were significantly larger with IMR CS than with FBP, HIR, and IMR CR. IMR CR showed the smallest attenuation difference, while attenuation was artificially decreased extensively with IMR CS. FBP and HIR showed moderately increased in-stent attenuations. No relevant influence of used radiation doses on visible lumen diameters or attenuation differences was found. CONCLUSION: IMR CR reduces image noise significantly while offering comparable stent-specific image quality in comparison to FBP and HIR and therefore potentially facilitates stent lumen delineation. Utilization of IMR CS for stent evaluation seems unfavorable due to artificial image alterations.