Human AI Teaming for Coronary CT Angiography Assessment: Impact on Imaging Workflow and Diagnostic Accuracy.

As the number of coronary computed tomography angiography (CTA) examinations is expected to increase, technologies to optimize the imaging workflow are of great interest. The aim of this study was to investigate the potential of artificial intelligence (AI) to improve clinical workflow and diagnostic accuracy in high-volume cardiac imaging centers. A total of 120 patients (79 men; 62.4 (55.0-72.7) years; 26.7 (24.9-30.3) kg/m2) undergoing coronary CTA were randomly assigned to a standard or an AI-based (human AI) coronary analysis group. Severity of coronary artery disease was graded according to CAD-RADS. Initial reports were reviewed and changes were classified. Both groups were similar with regard to age, sex, body mass index, heart rate, Agatston score, and CAD-RADS. The time for coronary CTA assessment (142.5 (106.5-215.0) s vs. 195.0 (146.0-265.5) s; p < 0.002) and the total reporting time (274.0 (208.0-377.0) s vs. 350 (264.0-445.5) s; p < 0.02) were lower in the human AI than in the standard group. The number of cases with no, minor, or CAD-RADS relevant changes did not differ significantly between groups (52, 7, 1 vs. 50, 8, 2; p = 0.80). AI-based analysis significantly improves clinical workflow, even in a specialized high-volume setting, by reducing CTA analysis and overall reporting time without compromising diagnostic accuracy.

Simultaneous assessment of heart and lungs with gated high-pitch ultra-low dose chest CT using artificial intelligence-based calcium scoring.

Purpose: The combined testing for coronary artery and pulmonary diseases is of clinical interest as risk factors are shared. In this study, a novel ECG-gated tin-filtered ultra-low dose chest CT protocol (GCCT) for integrated heart and lung acquisition and the applicability of artificial intelligence (AI)-based coronary artery calcium scoring were assessed. Methods: In a clinical registry of 10481 patients undergoing heart and lung CT, GCCT was applied in 44 patients on a dual-source CT. Coronary calcium scans (CCS) with 120 kVp, 100 kVp, and tin-filtered 100 kVp (Sn100) of controls, matched with regard to age, sex, and body-mass index, were retrieved from the registry (ntotal=176, 66.5 (59.4-74.0) years, 52 men). Automatic tube current modulation was used in all scans. In 20 patients undergoing GCCT and Sn100 CCS, Agatston scores were measured both semi-automatically by experts and by AI, and classified into six groups (0, <10, <100, <400, <1000, ≥1000). Results: Effective dose decreased significantly from 120 kVp CCS (0.50 (0.41-0.61) mSv) to 100 kVp CCS (0.34 (0.26-0.37) mSv) to Sn100 CCS (0.14 (0.11-0.17) mSv). GCCT showed higher values (0.28 (0.21-0.32) mSv) than Sn100 CCS but lower than 120 kVp and 100 kVp CCS (all p < 0.05) despite greater scan length. Agatston scores correlated strongly between GCCT and Sn100 CCS in semi-automatic and AI-based measurements (both ρ = 0.98, p < 0.001) resulting in high agreement in Agatston score classification (κ = 0.97, 95% CI 0.92-1.00; κ = 0.89, 95% CI 0.79-0.99). Regarding chest findings, further diagnostic steps were recommended in 28 patients. Conclusions: GCCT allows for reliable coronary artery disease and lung cancer screening with ultra-low radiation exposure. GCCT-derived Agatston score shows excellent agreement with standard CCS, resulting in equivalent risk stratification.

How scan parameter choice affects deep learning-based coronary artery disease assessment from computed tomography.

Recently, algorithms capable of assessing the severity of Coronary Artery Disease (CAD) in form of the Coronary Artery Disease-Reporting and Data System (CAD-RADS) grade from Coronary Computed Tomography Angiography (CCTA) scans using Deep Learning (DL) were proposed. Before considering to apply these algorithms in clinical practice, their robustness regarding different commonly used Computed Tomography (CT)-specific image formation parameters-including denoising strength, slab combination, and reconstruction kernel-needs to be evaluated. For this study, we reconstructed a data set of 500 patient CCTA scans under seven image formation parameter configurations. We select one default configuration and evaluate how varying individual parameters impacts the performance and stability of a typical algorithm for automated CAD assessment from CCTA. This algorithm consists of multiple preprocessing and a DL prediction step. We evaluate the influence of the parameter changes on the entire pipeline and additionally on only the DL step by propagating the centerline extraction results of the default configuration to all others. We consider the standard deviation of the CAD severity prediction grade difference between the default and variation configurations to assess the stability w.r.t. parameter changes. For the full pipeline we observe slight instability (± 0.226 CAD-RADS) for all variations. Predictions are more stable with centerlines propagated from the default to the variation configurations (± 0.122 CAD-RADS), especially for differing denoising strengths (± 0.046 CAD-RADS). However, stacking slabs with sharp boundaries instead of mixing slabs in overlapping regions (called true stack ± 0.313 CAD-RADS) and increasing the sharpness of the reconstruction kernel (± 0.150 CAD-RADS) leads to unstable predictions. Regarding the clinically relevant tasks of excluding CAD (called rule-out; AUC default 0.957, min 0.937) and excluding obstructive CAD (called hold-out; AUC default 0.971, min 0.964) the performance remains on a high level for all variations. Concluding, an influence of reconstruction parameters on the predictions is observed. Especially, scans reconstructed with the true stack parameter need to be treated with caution when using a DL-based method. Also, reconstruction kernels which are underrepresented in the training data increase the prediction uncertainty.

Factors influencing the safety of outpatient coronary CT angiography: a clinical registry study.

OBJECTIVES: Since the safety of coronary CT angiography (CTA) is of great importance, especially with regard to widening indications and increasing morbidity, the aim of this study was to assess influencing factors. METHODS: Patients undergoing coronary CTA in a third-generation dual-source CT in a radiological centre were included in a clinical registry. Up to 20 mg metoprolol was administered intravenously to attain a heart rate ≤65/min. Glyceryl trinitrate (GTN) was administered in doses of 0.8 mg and 0.4 mg. Blood pressure was measured before the administration and after the CTA. RESULTS: Out of 5500 consecutive patients (3194 men, 62.3 (54.9-70.0) years), adverse events occurred in 68 patients (1.2%) with mild anaphylactoid reactions (0.4%), vasovagal symptoms (0.3%) and extravasation (0.3%) being most frequent. Anti-allergic drugs were given in 17 patients, atropine in 3 patients and volume in 1 patient. Drug administration resulted in a significant mean arterial pressure decline (96.0 (88.3-106.0) vs 108.7 (99.7-117.3) mmHg; p<0.001). Patients who suffered systolic blood pressure drops >20 mmHg or >40 mmHg were older (66.5 (58.6-73.3) vs 60.5 (53.6-68.3) years; 70.2 (63.3-76.5) vs 62.1 (54.7-69.6) years), more often male (65.1% vs 54.4%; 68.9% vs 57.3%) and had higher Agatston score equivalents (83.0 (2.0-432.0) vs 15.0 (0.0-172.0); 163.0 (16.3-830.8) vs 25.0 (0.0-220.0); all p<0.001). GTN dose reduction lowered the fraction of patients suffering from blood pressure drops >20 mmHg or >40 mmHg from 34.5% to 27.4% and from 6.1% to 3.5% (both p<0.001), respectively. The proportion of coronary segments with impaired image quality did not differ significantly. CONCLUSIONS: Coronary CTA with intravenous beta-blocker administration is a safe procedure in an outpatient setting as adverse events are rare and mostly mild. Reduced GTN doses can further improve safety by lowering the rate of significant blood pressure drops, which occurred especially in elderly men with increased plaque burden. TRIAL REGISTRATION NUMBER: NCT03815123.

Deep learning for vessel-specific coronary artery calcium scoring: validation on a multi-centre dataset.

AIMS: To present and validate a fully automated, deep learning (DL)-based branch-wise coronary artery calcium (CAC) scoring algorithm on a multi-centre dataset. METHODS AND RESULTS: We retrospectively included 1171 patients referred for a CAC computed tomography examination. Total CAC scores for each case were manually evaluated by a human reader. Next, each dataset was fully automatically evaluated by the DL-based software solution with output of the total CAC score and sub-scores per coronary artery (CA) branch [right coronary artery (RCA), left main (LM), left anterior descending (LAD), and circumflex (CX)]. Three readers independently manually scored the CAC for all CA branches for 300 cases from a single centre and formed the consensus using a majority vote rule, serving as the reference standard. Established CAC cut-offs for the total Agatston score were used for risk group assignments. The performance of the algorithm was evaluated using metrics for risk class assignment based on total Agatston score, and unweighted Cohen's Kappa for branch label assignment. The DL-based software solution yielded a class accuracy of 93% (1085/1171) with a sensitivity, specificity, and accuracy of detecting non-zero coronary calcium being 97%, 93%, and 95%. The overall accuracy of the algorithm for branch label classification was 94% (LM: 89%, LAD: 91%, CX: 93%, RCA: 100%) with a Cohen's kappa of k = 0.91. CONCLUSION: Our results demonstrate that fully automated total and vessel-specific CAC scoring is feasible using a DL-based algorithm. There was a high agreement with the manually assessed total CAC from a multi-centre dataset and the vessel-specific scoring demonstrated consistent and reproducible results.

Biomechanical Influences on Mesh-Related Complications in Incisional Hernia Repair.

Aim: Hernia repair strengthens the abdominal wall with a textile mesh. Recurrence and pain indicate weak bonds between mesh and tissue. It remains a question which biomechanical factors strengthen the mesh-tissue interface, and whether surgeons can enhance the bond between mesh and tissue. Material and Methods: This study assessed the strength of the mesh-tissue interface by dynamic loads. A self-built bench test delivered dynamic impacts. The test simulated coughing. Porcine and bovine tissue were used for the bench test. Tissue quality, mesh adhesiveness, and fixation intensity influenced the retention power. The influences were condensed in a formula to assess the durability of the repair. The formula was applied to clinical work. The relative strength of reconstruction was related to the individual human abdominal wall. From computerized tomography at rest and during Valsalva's Maneuver, the tissue quality of the individual patient was determined before surgery. Results: The results showed that biomechanical parameters observed in porcine, bovine, and human tissue were in the same range. Tissues failed in distinct patterns. Sutures slackened or burst at vulnerable points. Both the load duration and the peak load increased destruction. Stress concentrations elevated failure rates. Regional areas of force contortions increased stress concentrations. Hernia repair improved strain levels. Measures for improvement included the closure of the defect, use of higher dynamic intermittent strain (DIS) class meshes, increased mesh overlap, and additional fixation. Surgeons chose the safety margin of the reconstruction as desired. Conclusion: The tissue quality has now been introduced into the concept of a critical and a gained resistance toward pressure-related impacts. A durable hernia repair could be designed from available coefficients. Using biomechanical principles, surgeons could minimize pain levels. Mesh-related complications such as hernia recurrence can potentially be avoided in incisional hernia repair.

Short-Time Changes in Coronary Artery Plaques Assessed by Follow-Up Coronary CT Angiography-Characteristics and Impact on Patient Management.

Background: Coronary artery disease (CAD) shows a chronic but heterogeneous clinical course. Coronary CT angiography (CTA) allows for the visualization of the entire coronary tree and the detection of early stages of CAD. The aim of this study was to assess short-time changes in non-calcified and mixed plaques and their clinical impact using coronary CTA in a real-world setting. Methods: Between 11/2014 and 07/2019, 6,701 patients had a coronary CTA with a third-generation dual-source CT, of whom 77 patients (57 males, 63.8 ± 10.8 years) with a chronic CAD received clinically indicated follow-up CTA. Non-calcified and mixed plaques were analyzed in 1,211 coronary segments. Patients were divided into groups: stable, progressive, or regressive plaques. Results: Within the follow-up period of 22.3 ± 10.4 months, 44 patients (58%) showed stable plaques, 27 (36%) showed progression, 5 (7%) showed regression. One patient was excluded due to an undetermined CAD course showing both, progressive and regressive plaques. Age did not differ significantly between groups. Patients with plaque regression were predominantly female (80 vs. 20%), whereas patients showing progression were mainly male (85 vs. 15%; p < 0.01 for both). Regression was only observed in patients with mild CAD or one-vessel disease. The follow-up CTA led to changes in patient management in the majority of subjects (n = 50; 66%). Conclusions: Changes in coronary artery plaques can be observed within a short period resulting in an adjustment of the clinical management in the majority of CAD patients. Follow-up coronary CTA renders the non-invasive assessment of plaque development possible and allows for an individualized diagnostics and therapy optimization.

The Grip Concept of Incisional Hernia Repair-Dynamic Bench Test, CT Abdomen With Valsalva and 1-Year Clinical Results.

Incisional hernia is a frequent consequence of major surgery. Most repairs augment the abdominal wall with artificial meshes fixed to the tissues with sutures, tacks, or glue. Pain and recurrences plague at least 10-20% of the patients after repair of the abdominal defect. How should a repair of incisional hernias be constructed to achieve durability? Incisional hernia repair can be regarded as a compound technique. The biomechanical properties of a compound made of tissue, textile, and linking materials vary to a large extent. Tissues differ in age, exercise levels, and comorbidities. Textiles are currently optimized for tensile strength, but frequently fail to provide tackiness, dynamic stiction, and strain resistance to pulse impacts. Linking strength with and without fixation devices depends on the retention forces between surfaces to sustain stiction under dynamic load. Impacts such a coughing or sharp bending can easily overburden clinically applied composite structures and can lead to a breakdown of incisional hernia repair. Our group developed a bench test with tissues, fixation, and textiles using dynamic intermittent strain (DIS), which resembles coughing. Tissue elasticity, the size of the hernia under pressure, and the area of instability of the abdominal wall of the individual patient was assessed with low-dose computed tomography of the abdomen preoperatively. A surgical concept was developed based on biomechanical considerations. Observations in a clinical registry based on consecutive patients from four hospitals demonstrate low failure rates and low pain levels after 1 year. Here, results from the bench test, the application of CT abdomen with Valsalva's maneuver, considerations of the surgical concept, and the clinical application of our approach are outlined.

Primary and Recurrent Repair of Incisional Hernia Based on Biomechanical Considerations to Avoid Mesh-Related Complications.

Aim: Mechanical principles successfully guide the construction of polymer material composites in engineering. Since the abdominal wall is a polymer composite augmented with a textile during incisional hernia repair we ask: can incisional hernia be repaired safely and durably based on biomechanical principles? Material and Methods: Repair materials were assessed on a self-built bench test using pulse loads to elude influences on the reconstruction of the abdominal wall. Tissue elasticity was analyzed preoperatively as needed with computed tomography at rest and during Valsalva's maneuver. Preoperatively, the critical retention force of the reconstruction to pulse loads was calculated and a biomechanically durable repair was designed based on the needs of the individual patient. Intraoperatively, the design was adjusted as needed. Hernia meshes with high grip factors (Progrip®, Dahlhausen® Cicat) were used for the repairs. Mesh sizes, fixation elements and reconstructive details were oriented on the biomechanical design. All patients recieved single-shot antibiosis. Patients were discharged after full ambulation was achieved. Results: A total of 163 patients (82 males and 81 females) were treated for incisional hernia in four hospitals by ten surgeons. Primary hernia was repaired in 119 patients. Recurrent hernia was operated on in 44 cases. Recurrent hernia was significantly larger (median 161 cm2 vs. 78 cm2; u-test: p = 0.00714). Re-do surgery took significantly longer (median 229 min vs. 150 min; p < 0.00001) since recurrent disease required more often transversus abdominis release (70% vs. 47%). GRIP tended to be higher in recurrent repair (p = 0.01828). Complication rates (15%) and hospital stay were the same (6 vs. 6 days; p = 0.28462). After 1 year, no recurrence was detected in either group. Pain levels were equally low in both primary and recurrent hernia repairs (median NAS = 0 in both groups at rest and under load, p = 0.88866). Conclusion: Incisional hernia can safely and durably be repaired based on biomechanical principles both in primary and recurrent disease. The GRIP concept provides a base for the application of biomechanical principles in incisional hernia repair.

Limits of the possible: diagnostic image quality in coronary angiography with third-generation dual-source CT.

BACKGROUND: The usage of coronary CT angiography (CTA) is appropriate in patients with acute or chronic chest pain; however the diagnostic accuracy may be challenged with increased Agatston score (AS), increased heart rate, arrhythmia and severe obesity. Thus, we aim to determine the potential of the recently introduced third-generation dual-source CT (DSCT) for CTA in a 'real-life' clinical setting. METHODS: Two hundred and sixty-eight consecutive patients (age: 67 ± 10 years; BMI: 27 ± 5 kg/m²; 61% male) undergoing clinically indicated CTA with DSCT were included in the retrospective single-center analysis. A contrast-enhanced volume dataset was acquired in sequential (SSM) (n = 151) or helical scan mode (HSM) (n = 117). Coronary segments were classified in diagnostic or non-diagnostic image quality. A subset underwent invasive angiography to determine the diagnostic accuracy of CTA. RESULTS: SSM (96.8 ± 6%) and HSM (97.5 ± 8%) provided no significant differences in the overall diagnostic image quality. However, AS had significant influence on diagnostic image quality exclusively in SSM (B = 0.003; p = 0.0001), but not in HSM. Diagnostic image quality significantly decreased in SSM in patients with AS ≥2,000 (p = 0.03). SSM (sensitivity: 93.9%; specificity: 96.7%; PPV: 88.6%; NPV: 98.3%) and HSM (sensitivity: 97.4%; specificity: 94.3%; PPV: 86.0%; NPV: 99.0%) provided comparable diagnostic accuracy (p = n.s.). SSM yielded significantly lower radiation doses as compared to HSM (2.1 ± 2.0 vs. 5.1 ± 3.3 mSv; p = 0.0001) in age and BMI-matched cohorts. CONCLUSION: SSM in third-generation DSCT enables significant dose savings and provides robust diagnostic image quality in patients with AS ≤2000 independent of heart rate, heart rhythm or obesity.

Incidence of renal infarctions after transrenal stent placement in an animal model.

PURPOSE: To evaluate the incidence and appearance of renal infarctions after transrenal stent placement in an animal model. METHODS: An aortic stent was placed via a femoral approach in 20 female Merino sheep. Ten animals had intentional coverage of one renal ostium with the bare struts, 1 sheep had both renal artery ostia covered, and the other 9 sheep had no stent impingement on the renal orifices. Animals were sacrificed after 3 to 12 months (mean 6) for gross pathological and histological evaluation. Infarction locations and patterns were evaluated and correlated to stent placement. RESULTS: Of the 40 renal arteries, coverage was proven at autopsy in 12 cases; the remaining 28 arteries were free of any stent overlay. Overall, 14 (35%) renal infarctions were detected; 7 were found in the 12 arteries with a transrenal stent (58.3% incidence in covered renal arteries). By comparison, the other 7 infarctions were found in the 28 unaffected arteries (25% incidence in noncovered renal arteries; p = 0.04). All infarctions appeared to be well-defined punctate lesions. CONCLUSIONS: A transrenal stent position in the abdominal aorta is related to increased renal infarctions in an animal model.

Complications after endovascular treatment of thoracic aortic aneurysms.

PURPOSE: To retrospectively determine the value of stent-graft repair of descending thoracic aortic aneurysms by analyzing the results and complications. METHODS: From May 1997 to July 2002, 45 patients (33 men; mean age 69 years, range 31-88) received endovascular treatment for thoracic aortic aneurysms. In 11 patients, emergency treatment was necessary for a contained rupture. The medical records of these patients were reviewed to gather data on the procedures, immediate results, complications, mortality, and survival in follow-up. RESULTS: In all cases, the stent-grafts were successfully implanted. In 15 (33%) cases, the subclavian artery was covered by the stent-graft without complications. There was no paraparesis/paraplegia; 2 (4.4%) patients suffered a stroke intraoperatively. The in-hospital mortality was 2.2% (n=1); 3 (6.7%) patients died within 30 days. Primary endoleaks occurred in 8 (17.8%) cases. Procedural success (technical success without endoleak or death) was 80% (93.3% after primary endoleak repair). During follow-up, 2 (4.4%) secondary endoleaks developed. All endoleaks were treated successfully or sealed spontaneously (n=2). At a mean 24-month follow-up (range 1-62), 84% of patients were alive. CONCLUSIONS: The endovascular treatment of thoracic aortic aneurysms appears to be safe and effective, with lower morbidity and mortality than in conventional open operations. For these reasons, endovascular treatment should be administered whenever possible.

Endovascular stent-graft repair of ruptured aortic aneurysms.

PURPOSE: To demonstrate the endovascular approach to the management of ruptured abdominal aortic aneurysms (AAA). METHODS: From 1995 to 2001, 24 patients (21 men; mean age 69 years, range 26-92) underwent emergency endovascular treatment for ruptured AAA. The average interval between onset of symptoms and admission to the hospital was 8.0 hours; the mean time between admission and the operation was 2.3 hours. No suprarenal occluding catheter was used. The stent-graft configurations were 19 bifurcated, 4 tube, and 1 aortomonoiliac. RESULTS: Stent-graft placement was successful in 23 (96%) cases. Failed limb extension deployment prompted conversion to open surgery in the remaining patient. One case was converted to open surgery. Mean duration of treatment was 122 minutes. Three (12.5%) patients died in-hospital. The median hospital stay was 12 days. The rate of endoleaks (all type I) was 16.7%. The overall technical success rate was 77%. The 3-year actuarial survival rate was 75%. CONCLUSIONS: Our experience shows excellent results in emergency patients with ruptured AAAs treated with endovascular surgery. In order to verify these promising results, a broader-scale clinical study must be conducted.

Endovascular repair of traumatic descending aortic transection.

PURPOSE: To present the results of endovascular repair of acute traumatic descending aortic transection. METHODS: Among 66 thoracic stent-graft repairs performed between 1995 and 2001, 11 patients (9 men; mean age 34 years, range 12-73) underwent emergent endovascular repair of acute traumatic descending aortic transection following traffic accidents. Immediate treatment of aortic rupture was indicated in all patients because of a marked fresh hematoma with hemothorax; the spiral computed tomographic (CT) scans showed circular or semicircular descending thoracic aortic injuries. The devices used included 11 thoracic Excluders and 1 Talent stent-graft. RESULTS: No patient required conversion to an open transthoracic operation. No patient developed temporary or permanent neurological deficit after endovascular treatment. Two type I endoleaks required periprocedural treatment: a second stent-graft was deployed in one and the existing stent-graft was balloon dilated in the other. Two patients underwent secondary procedures (iliac access complication and revascularization of the left subclavian artery). One patient died 22 days postoperatively secondary to injuries unrelated to the aortic repair. Over a mean 14-month follow-up (range 1-26), the surveillance CT scans have shown the stent-graft to be correctly positioned in all patients. CONCLUSIONS: The treatment of acute traumatic descending aortic transection with an endovascular approach is feasible and safe and may offer the best means of therapy. Mortality and the risk of neurological deficit are low compared with open operations.

Interventional treatment of traumatic priapism.

PURPOSE: To describe the effectiveness of transarterial embolization of traumatic priapism. METHODS: Six patients ranging in age from 6 to 37 years with traumatic high-flow priapism underwent superselective embolization with gelatin sponges (n=3) or minicoils (n=3). Embolization was repeated up to 3 times. RESULTS: Embolization was successful in all cases. In 2 patients, repeated embolization led to a flow reduction in the fistula, which spontaneously occluded a few days later. All patients experienced normal erections after intervention, and no side effects were observed. CONCLUSIONS: Transarterial superselective embolization is an effective and well-tolerated therapy in patients with traumatic priapism.

Contrast-enhanced 3D MRA of the aortoiliac and infrainguinal arteries when conventional transfemoral arteriography is not feasible.

PURPOSE: To evaluate whether contrast-enhanced 3-dimensional (3D) magnetic resonance angiography (MRA) can substitute for transaxillary or transbrachial catheter access when angiography via the transfemoral route is not possible. METHODS: Contrast-enhanced 3D MRA was performed in 14 patients (12 men; mean 66.1 +/- 12.4 years, range 48-98) with atherosclerotic disease of the aorta or lower extremities in whom conventional transfemoral arteriography was not feasible. The images were evaluated for their ability to identify and characterize lesions directly responsible for the patient's symptoms, adequately depict the vascular anatomy for therapy planning, and identify additional lesions not directly responsible for the patient's symptoms. The arterial system was divided into 15 segments, and image quality and the presence of occlusive disease were determined. RESULTS: MRA adequately depicted 387 (95%) of 406 arterial segments in 14 patients. Nineteen (5%) arterial segments were inadequately delineated because of low signal intensity distal from severe stenoses (n = 11), venous overlap (n = 6), or metallic clip-induced signal voids (n = 2). The lesions directly responsible for the patients' symptoms were identified in all 14 patients (2 aortic occlusions [Leriche's syndrome] and 12 iliac occlusions or severe stenoses). Visualization of the vascular anatomy was adequate for therapy planning in 13 of 14 patients, and 3D MRA satisfactorily identified other lesions not directly responsible for the current symptoms. CONCLUSIONS: When transfemoral catheter angiography of the aortoiliac and lower extremities is not feasible, contrast-enhanced 3D MRA is suitable for determining and planning therapy and can be used instead of angiography via the transaxillary or transbrachial routes.

Prospective evaluation of a clinical score for 60-day mortality after transjugular intrahepatic portosystemic stent-shunt: Bonn TIPSS early mortality analysis.

OBJECTIVE: Transjugular intrahepatic portosystemic stent-shunt (TIPSS) is increasingly used to treat complications of portal hypertension, but proven tools for risk assessment of early mortality are lacking. DESIGN: The prospective evaluation of a new 60-day mortality score. PATIENTS AND METHODS: In a tertiary medical centre, 30 consecutive TIPSS patients were analysed for early mortality predictors, such as Child-Pugh score, TIPSS urgency (elective: > or = 36 h or emergency: < 36 h after variceal bleeding), comorbidity (Acute Physiology and Chronic Health Evaluation [APACHE]-II) and clinical data. Main predictors (P< 0.01) in this group (group-1: Child-Pugh score 10A, 10B, 10C) were graded (1, 2 or 3 points representing low, medium and high risk, respectively) and summarized as a Bonn TIPSS early mortality (BOTEM) score. This score was then tested prospectively in the next 73 TIPSS patients (group-2: Child-Pugh score 14A, 42B, 17C). RESULTS: Group 1 early mortality (30%) depended primarily on bilirubin (P< 0.005), APACHE-II (P < 0.001) and TIPSS urgency (P< 0.001). Added risk points (1, 2, 3) for bilirubin (< 3 mg/dl, 3-6 mg/dl, > 6 mg/dl, respectively), APACHE-II (< 10, 10-20, > 20 points, respectively) and urgency (elective, emergency, active bleeding, respectively) represented individual BOTEM score points. BOTEM was the best mortality predictor (P< 0.001); < or = / > 6 score points was the optimal cut-off, with 56% sensitivity, 100% specificity, 100% positive predictive value, 84% negative predictive value and 87% accuracy. In group 2, early mortality (8.2%) was again best predicted by BOTEM (P < 0.01) with the same cut-off and 67% sensitivity, 99% specificity, 80% positive predictive value, 97% negative predictive value and 96% accuracy. CONCLUSION: BOTEM score based on bilirubin, comorbidity and TIPSS-urgency predicts rather reliably post-TIPSS 60-day mortality and might optimize TIPSS treatment.

Transesophageal echocardiographic guidance of thoracic aortic stent-graft implantation.

PURPOSE: To evaluate the efficacy of intraoperative transesophageal echocardiography (TEE) as an adjunctive measure in guiding the implantation of endoluminal stent-grafts in the thoracic aorta. METHODS: TEE was used in 21 of 30 patients (27 men; median age 70 years; range 19-77) undergoing implantation of Excluder or Talent stent-grafts for management of 11 type B aortic dissections, 7 thoracic aortic aneurysms, 2 traumatic thoracic aortic ruptures, and an aortic coarctation. We evaluated the ability of TEE to provide evidence of (1) correct placement of the guidewire within the true lumen, (2) reduction in blood flow in the false lumen following stent deployment, and (3) early complications. RESULTS: Definite identification of the true lumen and a reliable evaluation of the position of the stent-graft guidewire during advancement were possible in all patients. Reduction of blood flow within the false lumen following deployment of the stent-graft was visualized in >70% of patients with aortic dissection. In the patient with aortic coarctation, TEE recognized the acute onset of aortic dissection following stent dilation, which resulted in immediate management with an additional stent. CONCLUSIONS: The intraoperative use of TEE in the implantation of stent-grafts in the thoracic aorta is not significantly invasive and is easily employed. It permits excellent evaluation of the correct placement of the stent guidewire and, in patients with aortic dissection, intraoperatively visualizes effective blood flow reduction in the false lumen following stent-graft deployment. Its ability to recognize early complications may indicate the need for additional maneuvers during the surgical procedure.

Magnetic resonance imaging versus multislice computed tomography of thoracic aortic endografts.

PURPOSE: To compare the potential of magnetic resonance imaging (MRI) to multislice computed tomography (CT) for evaluating stent-graft placement in the thoracic aorta. METHODS: Susceptibility artifacts in 2 different stent-graft systems (Talent and Excluder) were evaluated in vitro in 2 angulations (straight and 33 degrees curved) using 3 different MRI gradient echo sequences (True FISP, 2-dimensional FLASH, and 3-dimensional Turbo FLASH). The size of the stent-related artifact was measured, and the relative stent lumen was calculated. In vivo stent demarcation, stent patency, and additional findings were determined in 13 patients (3 Talent, 9 Excluder, and 1 combined) and compared to CT findings. RESULTS: In vitro, both endograft systems proved to be MR compatible, with the relative stent lumen value ranging from 82% to 100% in the straight configuration; in a curved model, the relative stent lumen value ranged from 56% to 92% with the 3D Turbo FLASH sequence, which provided the smallest susceptibility artifacts. The Excluder endoprosthesis caused significant signal inhomogeneity within the stent in a curved configuration. In vivo, MRI and multislice CT showed similar results, with CT imaging slightly superior in stent demarcation and MRI better in demonstrating thrombus. CT beam hardening artifacts were pronounced in the Talent system, while the Excluder device caused significant signal inhomogeneity within the stent on magnetic resonance angiography. CONCLUSIONS: Multislice CT and contrast-enhanced MRI are fast, reliable means of providing all relevant information for surveillance of fully MR-compatible stent-grafts in the thoracic aorta.