Automated assessment of cardiac pathologies on cardiac MRI using T1-mapping and late gadolinium phase sensitive inversion recovery sequences with deep learning.

BACKGROUND: A deep learning (DL) model that automatically detects cardiac pathologies on cardiac MRI may help streamline the diagnostic workflow. To develop a DL model to detect cardiac pathologies on cardiac MRI T1-mapping and late gadolinium phase sensitive inversion recovery (PSIR) sequences were used. METHODS: Subjects in this study were either diagnosed with cardiac pathology (n = 137) including acute and chronic myocardial infarction, myocarditis, dilated cardiomyopathy, and hypertrophic cardiomyopathy or classified as normal (n = 63). Cardiac MR imaging included T1-mapping and PSIR sequences. Subjects were split 65/15/20% for training, validation, and hold-out testing. The DL models were based on an ImageNet pretrained DenseNet-161 and implemented using PyTorch and fastai. Data augmentation with random rotation and mixup was applied. Categorical cross entropy was used as the loss function with a cyclic learning rate (1e-3). DL models for both sequences were developed separately using similar training parameters. The final model was chosen based on its performance on the validation set. Gradient-weighted class activation maps (Grad-CAMs) visualized the decision-making process of the DL model. RESULTS: The DL model achieved a sensitivity, specificity, and accuracy of 100%, 38%, and 88% on PSIR images and 78%, 54%, and 70% on T1-mapping images. Grad-CAMs demonstrated that the DL model focused its attention on myocardium and cardiac pathology when evaluating MR images. CONCLUSIONS: The developed DL models were able to reliably detect cardiac pathologies on cardiac MR images. The diagnostic performance of T1 mapping alone is particularly of note since it does not require a contrast agent and can be acquired quickly.

Assessment of Efficacy and Complications of Endovascular Interventions for Critical Limb Ischemia in Germany: A Nationwide Study.

PURPOSE: Endovascular interventional radiological procedures have become the mainstay for the treatment of critical limb ischemia (CLI) due to arterial stenosis or occlusion. Open surgical or endovascular procedures, such as percutaneous transluminal angioplasty (PTA) or stenting can be used as a treatment strategy. The aim is to evaluate the success and major complication rates of interventional radiology treatments for CLI in Germany in 2021, and to compare these results with internationally published data. MATERIALS AND METHODS: Data for PTA and stenting in CLI for 2021 was obtained from the quality management system of the German Society of Interventional Radiology (DeGIR). 16 393 PTA procedures, 701 stenting procedures, and 8110 combined procedures were documented for 2021. Data was analyzed for technical and clinical success rates, as well as major complication rates documented mainly as major bleeding, distal embolization, and aneurysm formation. RESULTS: PTA had technical and clinical success rates of 96.3 % and 92.33 %, respectively. Stenting had technical and clinical success rates of 98.7 % and 96.15 %, respectively. PTA and stenting combined had success rates of 98.71 % and 96.91 %, respectively. The major complications were mainly: major bleeding (PTA: 0.40 %; stenting: 1.28 %; PTA and stenting: 0.54 %), distal embolization (PTA: 0.48 %; stenting: 1 %; PTA and stenting: 0.96 %), and aneurysm formation (PTA: 0.19 %; stenting: 0.43 %; PTA and stenting: 0.19 %). All procedures showed high technical and clinical success rates, while the complication rates were low. CONCLUSION: Interventional radiologists in Germany perform effective and safe treatment for CLI, achieving outcomes that tend to surpass internationally published data. KEY POINTS: · German interventional radiologists provide safe and effective critical limb ischemia treatment.. · Major complications occurred at maximum in 1.28 % of cases.. · Outcomes tend to surpass international data, indicating strong performance..

Risk factors assessment for radiographically guided port implantations with forearm access.

INTRODUCTION: Port implantations at the forearm are associated with an increased risk of relevant vein thrombosis. Therefore, with this study we sought to identify the responsible risk factors to improve technical quality of the method. METHODS: This is a retrospective analysis of 313 patients with port implantation at the forearm in 2019. Then, exploratory statistics were conducted comprising Cox-Regression and Kaplan-Meier-Analyses. RESULTS: Mean age was 60 ± 14 years. 232 (74%) of the patients were female. No early infection was observed. 29 late infections and 57 cases of thrombosis occurred. In only 9% of the patients with thrombosis hospital admission was necessary for treatment. Median interval to the diagnosis of thrombosis was 23 days; inter-quartile-range: 16-75. Mean interval to elective port explantation was 227 ± 128 days. There was no effect of occurrence of thrombosis of the interventionalist, the assistance nor of several technical aspects. However, there was a significantly lower risk of thrombosis for primary implanted port system compared to replacement ports, Hazard-ratio: 0.34 [Confidence interval: 0.172, 0.674], p = 0.002. Age was a significant risk factor for late infections, Hazard-ratio: 3.35 [Confidence interval:1.84, 6.07], p < 0.0001. CONCLUSION: The main risk factor for adverse outcome after radiographically guided port implantation at the forearm is the type of the implanted port system. The reason for that might not be the material itself but the experience of a team with a certain port system. Age is a risk factor for late complications.

Availability of Transcatheter Vessel Occlusion Performed by Interventional Radiologists to Treat Bleeding in Germany in the Years 2016 and 2017 - An Analysis of the DeGIR Registry Data. / Flächendeckende Versorgung mit radiologisch durchgeführten gefäßverschließenden Maßnahmen zur interventionellen Behandlung von Blutungen in Deutschland in den Jahren 2016 und 2017 ­ Eine Analyse der DeGIR-Registerdaten.

PURPOSE: Acute bleeding is a life-threatening condition that can be effectively treated minimally invasively by interventional radiologists using transcatheter vessel occlusion (TCVO). The purpose of this study was to evaluate the availability of TCVO performed by interventional radiologists in Germany based on the DeGIR registry. MATERIALS AND METHODS: TCVO interventions from the years 2016 and 2017 were included (DeGIR module B). The number of interventions was assessed by state and region. RESULTS: TCVO interventions were reported by 242 clinics in Germany. 16 763 module B interventions were reported in 2016 and 16 399 in 2017. DeGIR requirements for certification as a training center were fulfilled by 160 facilities in 2016 and by 162 facilities in 2017. Normalized to one million citizens, an average of 211 TCVO interventions were performed in 2016 and 200 in 2017 (standard deviation was 101 and 109); the median was 202 and 222, respectively. In all regions TCVO interventions were reported. Only a minimal number of small regions showed a lower number of clinics offering TCVO interventions. CONCLUSION: The results from the DeGIR registry indicate comprehensive nationwide availability of TCVO performed by interventional radiologists with the necessary experience in Germany on the state level for the treatment of acute bleeding. Furthermore, the distribution of facilities fulfilling the requirements of training centers allows for good educational possibilities for young interventional radiologists in Germany. Only the distribution of clinics offering TCVO in a few small regions might lead to increased transfer times in the case of acute bleeding. KEY POINTS: · As a treatment for life-threatening acute bleeding in Germany, transcatheter vessel occlusion led by interventional radiologists is readily available on the state level.. · Furthermore, the distribution of facilities fulfilling the requirements of training centers allows for good educational possibilities for young interventional radiologists in Germany.. · Due to the good training conditions in Germany, it might be possible to further improve the situation in smaller regions by training more interventional radiologists and employing them in regions with less coverage.. CITATION FORMAT: · Nadjiri J, Schachtner B, Bücker A et al. Availability of Transcatheter Vessel Occlusion Performed by Interventional Radiologists to Treat Bleeding in Germany in the Years 2016 and 2017 - An Analysis of the DeGIR Registry Data. Fortschr Röntgenstr 2020; 192: 952 - 960.

Incremental prognostic value of quantitative plaque assessment in coronary CT angiography during 5 years of follow up.

OBJECTIVE: We sought to assess the incremental prognostic value of quantitative plaque characterization beyond established CT risk scores. BACKGROUND: Several plaque characteristics detectable by coronary computed tomographic angiography (coronary CTA) are thought to be indicative of vulnerable plaques and subsequent cardiac events, particularly low attenuation plaque volume (LAPV), positive remodeling and the napkin-ring sign which is high density vascular adhesion with a small center of low density. It is unknown how quantitative plaque assessment can contribute to the long-term prediction of cardiovascular events in relation to established CT risk scores such as the calcium score or Segment Stenosis Score (SSS). METHODS: In 1168 consecutive patients with suspected coronary artery disease (CAD), calcium score measurement and coronary plaque characterization was performed comprising the presence of calcified, non-calcified, and partially calcified plaques on a per-segment basis. In all non-calcified or partially calcified plaques, semi-automated plaque analysis was performed to quantify low attenuation plaque volume (density <30 HU), total non-calcified plaque volume (<150 HU, TNCPV) and remodeling index. The presence of the napkin-ring sign was assessed visually. The study endpoint was the occurrence of major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction and coronary revascularization more than 90 days after coronary CTA. RESULTS: During a clinical follow up of 5.7 years, MACE was observed in 46 patients (3.9%). All plaque characteristics were associated with MACE. The strongest association was observed for LAPV (HR 1.12, p < 0.0001). LAPV showed incremental prognostic value in a stepwise multivariable model including the Morise Score for clinical risk, calcium score and SSS (p = 0.036). CONCLUSION: LAPV, TPV, PR and presence of the napkin-ring sign are predictors of MACE independently of clinical risk presentation. LAPV carries slight additional prognostic information beyond the calcium score and conventional coronary CTA analysis. It may therefore improve risk prediction after CT imaging.

Reproducibility of area at risk assessment in acute myocardial infarction by T1- and T2-mapping sequences in cardiac magnetic resonance imaging in comparison to Tc99m-sestamibi SPECT.

Area at risk (AAR) is an important parameter for the assessment of the salvage area after revascularization in acute myocardial infarction (AMI). By combining AAR assessment by T2-weighted imaging and scar quantification by late gadolinium enhancement imaging cardiovascular magnetic resonance (CMR) offers a promising alternative to the "classical" modality of Tc99m-sestamibi single photon emission tomography (SPECT). Current T2 weighted sequences for edema imaging in CMR are limited by low contrast to noise ratios and motion artifacts. During the last years novel CMR imaging techniques for quantification of acute myocardial injury, particularly the T1-mapping and T2-mapping, have attracted rising attention. But no direct comparison between the different sequences in the setting of AMI or a validation against SPECT has been reported so far. We analyzed 14 patients undergoing primary coronary revascularization in AMI in whom both a pre-intervention Tc99m-sestamibi-SPECT and CMR imaging at a median of 3.4 (interquartile range 3.3-3.6) days after the acute event were performed. Size of AAR was measured by three different non-contrast CMR techniques on corresponding short axis slices: T2-weighted, fat-suppressed turbospin echo sequence (TSE), T2-mapping from T2-prepared balanced steady state free precession sequences (T2-MAP) and T1-mapping from modified look locker inversion recovery (MOLLI) sequences. For each CMR sequence, the AAR was quantified by appropriate methods (absolute values for mapping sequences, comparison with remote myocardium for other sequences) and correlated with Tc99m-sestamibi-SPECT. All measurements were performed on a 1.5 Tesla scanner. The size of the AAR assessed by CMR was 28.7 ± 20.9 % of left ventricular myocardial volume (%LV) for TSE, 45.8 ± 16.6 %LV for T2-MAP, and 40.1 ± 14.4 %LV for MOLLI. AAR assessed by SPECT measured 41.6 ± 20.7 %LV. Correlation analysis revealed best correlation with SPECT for T2-MAP at a T2-threshold of 60 ms (ms) (slope = 0.99, Pearson's r = 0.94), and for MOLLI at T1-threshold of 1,075 ms (slope 0.86, r = 0.91, Pearson's r = 0.45). For the assessment of AAR in AMI, the novel T2-mapping technique correlates best with SPECT size, T1-mapping with MOLLI and standard T2-weighted imaging showed similar good correlations.