Clinical pre-test probability for obstructive coronary artery disease: insights from the European DISCHARGE pilot study.

OBJECTIVES: To test the accuracy of clinical pre-test probability (PTP) for prediction of obstructive coronary artery disease (CAD) in a pan-European setting. METHODS: Patients with suspected CAD and stable chest pain who were clinically referred for invasive coronary angiography (ICA) or computed tomography (CT) were included by clinical sites participating in the pilot study of the European multi-centre DISCHARGE trial. PTP of CAD was determined using the Diamond-Forrester (D+F) prediction model initially introduced in 1979 and the updated D+F model from 2011. Obstructive coronary artery disease (CAD) was defined by one at least 50% diameter coronary stenosis by both CT and ICA. RESULTS: In total, 1440 patients (654 female, 786 male) were included at 25 clinical sites from May 2014 until July 2017. Of these patients, 725 underwent CT, while 715 underwent ICA. Both prediction models overestimated the prevalence of obstructive CAD (31.7%, 456 of 1440 patients, PTP: initial D+F 58.9% (28.1-90.6%), updated D+F 47.3% (34.2-59.9%), both p < 0.001), but overestimation of disease prevalence was higher for the initial D+F (p < 0.001). The discriminative ability was higher for the updated D+F 2011 (AUC of 0.73 95% confidence interval [CI] 0.70-0.76 versus AUC of 0.70 CI 0.67-0.73 for the initial D+F; p < 0.001; odds ratio (or) 1.55 CI 1.29-1.86, net reclassification index 0.11 CI 0.05-0.16, p < 0.001). CONCLUSIONS: Clinical PTP calculation using the initial and updated D+F prediction models relevantly overestimates the actual prevalence of obstructive CAD in patients with stable chest pain clinically referred for ICA and CT suggesting that further refinements to improve clinical decision-making are needed. TRIAL REGISTRATION: https://www.clinicaltrials.gov/ct2/show/NCT02400229 KEY POINTS: • Clinical pre-test probability calculation using the initial and updated D+F model overestimates the prevalence of obstructive CAD identified by ICA and CT. • Overestimation of disease prevalence is higher for the initial D+F compared with the updated D+F. • Diagnostic accuracy of PTP assessment varies strongly between different clinical sites throughout Europe.

Application of an advanced noise reduction algorithm for imaging of hands in rheumatic diseases: evaluation of image quality compared to standard-dose images.

OBJECTIVES: X-ray is the fundamental imaging technique in both diagnosis and follow-up of rheumatic diseases. As patients often require sequential X-rays over many years, dose reduction is of great importance. New advanced noise reduction algorithms allow for a dose reduction of up to 50%. The aim of this study was to evaluate whether quality of low-dose images is non-inferior to standard-dose images and, therefore, application of this technique is possible in the context of imaging of rheumatic diseases. METHODS: A total of 298 patients with known or suspected rheumatic disease were enrolled prospectively into this study, separated into three consecutive groups: 80%, 64% and 50% tube charge reduction. All patients received imaging of one hand (laterality randomly assigned) with low-dose technique and imaging of the contralateral hand with standard-dose protocol. Images were evaluated by two independent readers who scored (on a scale of 1-5) the visualization of bony cortex, trabeculae and joint spaces of fingers and wrist separately. Additionally, soft tissue and overall contrast were evaluated on the same scale. RESULTS: Overall image quality (expressed by mean sum score out of 40) of the 50% low-dose images was 31.52 (SD 1.94) vs. 31.66 (SD 1.82) for standard images (p = 0.068). Bony contours as well as trabeculae were equally well visualized in both image sets. Median scores for soft tissue visualization was slightly lower for low dose compared to standard images [4 (IQR 3.5-4) vs. 4 (IQR 3.88-4); p = 0.001]. CONCLUSIONS: Overall image quality of low-dose images was not inferior to standard-dose images. Therefore, the application of low-dose technology based on advanced noise estimation algorithms in the context of imaging of rheumatic diseases is possible.

Extracardiac findings on coronary computed tomography angiography in patients without significant coronary artery disease.

OBJECTIVE: To analyse extracardiac findings in patients without significant coronary artery disease (CAD) in general and in symptomatic patients in particular. METHODS: We searched the Radiology Information System database for coronary computed tomography angiographies (CTA) performed from 2000-2014 and retrospectively enrolled 3,898 patients without significant CAD (coronary stenosis < 50%) in CTA. In 2,330 symptomatic patients, we analysed the spectrum of extracardiac findings and identified pathologies potentially explaining chest pain. Finally, we investigated variables affecting the number of extracardiac findings detected in CTA. RESULTS: Overall extracardiac findings were found in 1,177 patients (30.2%; 95%CI, 28.8-31.7%). 94 patients (2.4%; 95%CI, 2.0-2.9%) had extracardiac findings with a recommendation for follow-up, sixteen patients (0.4%; 95%CI, 0.3-0.7%) had incidental urgent, and another three patients (0.1%; 95%CI, 0.1-0.2%) had incidental malignant extracardiac findings. 185 of 2,330 symptomatic patients (7.9%; 95%CI, 6.9-9.1%) revealed extracardiac findings potentially explaining chest pain after exclusion of significant CAD. The number of extracardiac findings increased significantly with patient age (p < 0.001) and the cumulative experience of the CT reader (p < 0.001). CONCLUSION: 30.2% of patients undergoing CTA for exclusion of CAD had ECF, and 7.9% of symptomatic patients without significant CAD on their examination had findings that could potentially explain their symptoms. KEY POINTS: • Of patients undergoing CTA, 2.8% have relevant incidental extracardiac findings. • CTA could identify the differential diagnosis of chest pain when excluding significant CAD. • Patient age and reader's professional experience influence the number of detected ECFs.

Extracardiac findings at cardiac MR imaging: a single-centre retrospective study over 14 years.

OBJECTIVES: To determine the prevalence and significance of extracardiac findings (ECF) in a large set of cardiac magnetic resonance (MR) imaging examinations. METHODS: The institutional review board (IRB) of the Charité approved this retrospective, single-centre study. A total of 4376 cardiac MR imaging reports of 3553 patients (age 37.4 ± 20 years, 60.8 % male) examined from 2000 to 2014 were included. Findings with a recommendation for follow-up were considered "major ECF". To analyse the association of indication, age and gender with ECF, Poisson regression and computed incidence rate ratios (IRR) were evaluated. RESULTS: The overall prevalence of ECF was 34% (95% confidence interval [CI] 32.5-35.6%). Major ECF were present in 3.4% (95% CI 2.9-4.1%) while findings that changed patient management were found in 0.9% (95% CI 0.7-1.3%). In the cases of congenital heart disease, ECF prevalence was higher compared to myocarditis (IRR, 6.0; 95% CI 5.1-7.1%; p < 0.001), while the prevalence of major ECF was lower (IRR, 0.2; 95% CI 0.02-0.51%; p < 0.05). Older patient age was associated with more nonvascular ECF (p < 0.001). Female patients had the same probability of having an ECF as male patients (IRR, 1.04; 95% CI 0.95-1.1%; p = 0.43). CONCLUSION: ECF in cardiac MR imaging are present in about every third patient while relevant ECF that change patient management can be found in about one out of 100 patients. Our data suggest that it is important to involve well-trained radiologists in reading cardiac MR images, which often reveal ECF if congenital heart disease is the clinical indication. KEY POINTS: • Extracardiac findings are present in about every third patient. • Relevant ECF changing patient management are found in one out of 100 findings. • Chance of ECF is high in patients with CHD and vascular indications.

Image quality of low-radiation dose left atrial CT using filtered back projection and an iterative reconstruction algorithm: intra-individual comparison in unselected patients undergoing pulmonary vein isolation.

Background Computed tomography (CT) of the left atrium (LA) is performed prior to pulmonary vein isolation (PVI) to improve success of circumferential ablation for atrial fibrillation. The ablation procedure itself exposes patients to substantial radiation doses, therefore radiation dose reduction in pre-ablational imaging is of concern. Purpose To assess and compare diagnostic performance of low-radiation dose preprocedural CT in patients scheduled for PVI using two types of reconstruction algorithms. Material and Methods Forty-six patients (61 ± 10 years) scheduled for PVI were enrolled in this study irrespective of body-mass-index or cardiac rhythm at examination. An electrocardiographically triggered dual-source CT scan was performed. Filtered back projection (FBP) and iterative reconstruction (IR) algorithms were applied. Images were integrated into an electroanatomic mapping (EAM) system. Subjective image quality was scored independently by two readers on a five-point scale for both reconstruction algorithms (1 = excellent to 5 = non-diagnostic). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and effective radiation dose were calculated. Results Data acquisition and EAM integration were successful in all patients. Median image quality score was 1 for both FBP (quartiles = 1, 1.62; range = 1-3) and IR (quartiles = 1, 1.5; range = 1-3). Mean SNR was 7.61 ± 2.14 for FBP and 9.02 ± 2.69 for IR. Mean CNR was 5.92 ± 1.80 for FBP and 6.95 ± 2.29 for IR. Mean effective radiation dose was 0.3 ± 0.1 mSv. Conclusion At a radiation dose of 0.3 ± 0.1 mSv, high-pitch dual-source CT yields LA images of consistently high quality using both FBP and IR. IR raises SNR and CNR without significantly improving subjective image quality.

Low Dose Computed Tomography for 3D Planning of Total Hip Arthroplasty: Evaluation of Radiation Exposure and Image Quality.

OBJECTIVE: The aim of the study was to compare radiation exposure and image quality between dedicated computed tomography (CT) protocols for preoperative total hip arthroplasty (THA) planning. METHODS: Three protocols with automated tube current modulation using 64-slice (n = 177) and 128-slice CT scanners without (n = 129) and with automated tube voltage preselection (n = 84) were compared. RESULTS: All 390 CTs were of sufficient quality for THA planning. Mean DLP was 235.0 mGy*cm (effective dose 2.8 mSv). Lowest radiation exposure (2.5 mSv) was seen with automated voltage preselection and the algorithm's selection was 100 kV (90.5% of patients) and 120 kV. Lowest image noise was seen in the highest dose group (3.1 mSv, 128-slice CT fixed tube voltage). A significant difference in cortical bone radiodensity was seen between 100 kV and 120 kV (P < 0.0001). CONCLUSIONS: Preoperative pelvic CT for THA planning is possible with very low radiation dose and reliable quality. Automated voltage preselection further decreases the effective dose by 18.2%.

High-pitch dual-source CT coronary angiography with low volumes of contrast medium.

OBJECTIVES: To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). METHODS: One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m(2)) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G30, 30 mL; G40, 40 mL; G50, 50 mL; G60, 60 mL; G70, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. RESULTS: Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G30 to 478.2 and 571.8 HU in G70. Mean attenuation values were higher in groups with higher CM volumes (P < 0.0001) and higher in women than in men (P < 0.0001). The proportions of segments with attenuation of at least 300 HU in G30, G40, G50, G60 and G70 were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. CONCLUSIONS: In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. KEY POINTS: • High-pitch dual-source coronary angiography is feasible with low contrast media volumes. • Traditional injection rules still apply: higher volumes result in higher enhancement. • The patient's gender is a co-factor determining the level of contrast enhancement. • Volumes can be reduced down to 30-40 mL in selected patients.

Clinical, anatomical, and technical risk factors for postoperative pacemaker or defibrillator lead perforation with particular focus on myocardial thickness.

BACKGROUND: Postoperative lead perforation is a life-threatening complication of cardiac pacing. Identification of precipitating factors for this serious complication may help to anticipate a specific risk profile and to minimize the incidence. METHODS: We conducted a retrospective tertiary referral center analysis to clarify clinical, anatomical, and technical characteristics related to pacemaker (PM) and cardioverter/defibrillator lead perforation. We examined the baseline characteristics and the symptoms. In a subgroup, we investigated the myocardial thickness on contrast-enhanced cardiac computed tomography. RESULTS: We enrolled 26 patients. Female gender appears to put patients at slightly increased risk for lead perforation. In a majority active fixation leads were used. Symptoms occurred in 72%. Pericardial effusion and tamponade were present in 38% and 19%, respectively. Sensing was compromised in 65%. A high pacing threshold or exit block occurred in 92%. Myocardial thickness did not differ between patients with or without perforation. In 96%, the perforation was treated by transvenous withdrawal. CONCLUSION: Chest pain, phrenic stimulation, bad sensing, or exit block early after PM implantation must prompt radiological and echocardiographic evaluation. A missing pericardial effusion particularly late after implantation does not rule out a perforation. Especially active fixating leads have a higher risk of perforation. With cardiac surgery in standby transvenous withdrawal is a safe way to treat lead perforation.

Predictors of residual tricuspid regurgitation after interventional therapy: an automated deep-learning CT analysis.

Computed tomography (CT) is used as a valuable tool for device selection for interventional therapy in tricuspid regurgitation (TR). We aimed to evaluate predictors of TR reduction using CT and automated deep learning algorithms. Patients with severe to torrential TR and CTs prior to either percutaneous annuloplasty (PA) or tricuspid transcatheter edge-to-edge repair (T-TEER) were enrolled. CTs were analyzed using automated deep learning algorithms to assess tricuspid valve anatomy, right heart morphology, and function. Outcome parameters comprised post-interventional TR ≤ 1 and all-cause mortality. 84 patients with T-TEER (n = 32) or PA treatment (n = 52) were enrolled. Patients with a post-interventional TR ≤ 1 presented lower tenting heights and smaller tenting angles compared to patients with a TR > 1. Tenting height showed the best accuracy for post-interventional TR > 1 with an AUC of 0.756 (95% CI 0.560-0.951) in the T-TEER and 0.658 (95% CI 0.501-0.815) in the PA group, consistent with a suggested threshold of 6.8 mm and 9.2 mm, respectively. Patients with a post-interventional TR ≤ 1 exhibited a mortality of 4% and those with a TR > 1 of 12% during a follow-up of 331 ± 300 and 370 ± 265 days, respectively (p = 0.124). To conclude, tenting is associated with procedural outcomes and should be considered during screening for interventional TR therapy.

Surgical-transcatheter approach for endocarditis of a calcified aortic homograft.

Repeat aortic valve replacement (AVR) after freestanding homograft root replacement with reimplantation of the coronary arteries is challenging and risky, especially in patients with major homograft wall calcifications. Although new transcatheter techniques for AVR may offer an alternative in structurally degenerated homografts, they are not suitable to treat endocarditis. Here, the case is reported of successful treatment of bacterial endocarditis within a totally calcified homograft after aortic root replacement by combining conventional surgery and transcatheter techniques.

Where did it hit harder? Understanding the geography of excess mortality during the COVID-19 pandemic.

The health impact of the COVID-19 pandemic across OECD (Organisation for Economic Co-operation and Development) and European regions has been strikingly uneven. In 2020, excess mortality rates in the hardest-hit regions were, on average, 17 percentage points higher than those in the least affected regions of the same country. This paper shows that low health system capacity, followed by population density, air pollution, the share of elderly people, and low institutional quality were associated with higher excess mortality during the first year of the pandemic. Finally, reduced home-to-work mobility, following governments' COVID-19 responses, was associated with lower excess mortality 2 months after implementation of the measures.

Pregnancy and breast cancer in a patient with complicated Kawasaki Disease, as if one problem was not enough: a case report.

Background: Due to the increasing prevalence of Kawasaki Disease (KD) in adulthood, the number of women considering pregnancy is growing. There are limited data on the course of pregnancy in KD with coronary artery involvement. Case summary: We report on the pregnancy outcome of a 30-year-old woman with KD who was successfully resuscitated for ventricular tachycardia 3 years before. At that time, bypass surgery and later implantable cardioverter-defibrillator implantation were performed because of thrombotically occluded calcified giant coronary aneurysms. The pregnancy course was initially uncomplicated, however, at 31 weeks of gestation, left-sided breast cancer was diagnosed. Weighing maximum therapeutic efficacy against acceptable foetal and maternal cardiotoxic risk, our multidisciplinary team decided on neoadjuvant chemotherapy. The mother and foetus tolerated the therapy well. However, at 36 weeks of gestation, due to HELLP (haemolysis, elevated liver, low platelets) syndrome, a caesarean section had to be performed. The newborn was healthy with good APGAR (appearance, pulse, grimace, activity, respiration) scores. Three weeks after delivery, chemotherapy was restarted and at Week 4 after the caesarean section, the tumour was no more detectable. Discussion: We discuss data on pregnancy and KD and outline that pregnancy can be considered if the clinical condition is good and left ventricular function is preserved. We also address possible therapeutic approaches and care for breast cancer in pregnancy and coexisting cardiovascular disease. The extraordinary importance of interdisciplinary cooperation between different disciplines in such complex clinical disease conditions is emphasized.

Valve embolization during transcatheter aortic valve implantation: Incidence, risk factors and follow-up by computed tomography.

Background: In most cases of transcatheter valve embolization and migration (TVEM), the embolized valve remains in the aorta after implantation of a second valve into the aortic root. There is little data on potential late complications such as valve thrombosis or aortic wall alterations by embolized valves. Aims: The aim of this study was to analyze the incidence of TVEM in a large cohort of patients undergoing transcatheter aortic valve implantation (TAVI) and to examine embolized valves by computed tomography (CT) late after TAVI. Methods: The patient database of our center was screened for cases of TVEM between July 2009 and July 2021. To identify risk factors, TVEM cases were compared to a cohort of 200 consecutive TAVI cases. Out of 35 surviving TVEM patients, ten patients underwent follow-up by echocardiography and CT. Results: 54 TVEM occurred in 3757 TAVI procedures, 46 cases were managed percutaneously. Horizontal aorta (odds ratio [OR] 7.51, 95% confidence interval [CI] 3.4-16.6, p < 0.001), implantation of a self-expanding valve (OR 4.63, 95% CI 2.2-9.7, p < 0.01) and a left ventricular ejection fraction < 40% (OR 2.94, 95% CI 1.1-7.3, p = 0.016) were identified as risk factors for TVEM. CT scans were performed on average 26.3 months after TAVI (range 2-84 months) and detected hypoattenuated leaflet thickening (HALT) in two patients as well as parts of the stent frame protruding into the aortic wall in three patients. Conclusion: TVEM represents a rare complication of TAVI. Follow up-CT detected no pathological findings requiring intervention.

Low-dose triple-rule-out using 320-row-detector volume MDCT--less contrast medium and lower radiation exposure.

OBJECTIVES: To investigate image quality of triple-rule-out (TRO) computed tomography (CT) using a 320-row-detector CT system with substantially reduced contrast medium volume at 100 kV. METHODS: Forty-six consecutive patients with noncritical, acute chest pain underwent 320-row-detector CT using a two-step TRO protocol consisting of a non-spiral, non-gated chest CT acquisition (150 mA) followed by a non-spiral, electrocardiography-gated cardiac acquisition (200-500 mA based on body mass index (BMI)). Data were acquired using a biphasic injection protocol with a total iodinated contrast medium volume of 60 ml (370 mg/ml). Vessel attenuation and effective doses were recorded. Image quality was scored independently by two readers. RESULTS: Mean attenuation was 584 ± 114 Hounsfield units (HU) in the ascending aorta, 335 ± 63HU in the aortic arch, 658 ± 136HU in the pulmonary trunk, and 521 ± 97HU and 549 ± 102HU in the right and left coronary artery, respectively. In all but one patient, attenuation and image quality allowed accurate visualization of the pulmonary arteries, thoracic aorta, and coronary arteries in a single examination. Ninety-six percent of all coronary artery segments were rated diagnostic. Radiation exposure ranged between 2.0 and 3.3 mSv. CONCLUSION: Using 320-row-detector CT the investigated low-dose TRO protocol resulted in excellent opacification and image quality with substantial reduction of contrast medium volume compared to recently published TRO protocols.

Assessment of mitral valve stenosis by helical MDCT: comparison with transthoracic doppler echocardiography and cardiac catheterization.

OBJECTIVE: We evaluated the precision of helical MDCT for the quantification of mitral valve stenosis (MVS) compared with transthoracic echocardiography (TTE) and cardiac catheterization. MATERIALS AND METHODS: A total of 28 patients with MVS of differing severity underwent an ECG-gated contrast-enhanced MDCT scan. The mitral valve area (MVA) was determined planimetrically by MDCT and was compared with Doppler TTE using the pressure half-time method and with cardiac catheterization using the Gorlin formula. RESULTS: Planimetry of the MVA with MDCT was feasible in all cases. The MVA on MDCT (1.88 ± 0.76 cm(2)) was significantly larger than that seen with TTE (1.74 ± 0.75 cm(2); p = 0.039) or cardiac catheterization (1.72 ± 0.67 cm(2); p = 0.037). The correlation between MDCT and TTE (r = 0.90; p < 0.001; limits of agreement, ± 0.65 cm(2)) and that between MDCT and cardiac catheterization (r = 0.86; p < 0.001; limits of agreement, ± 0.76 cm(2)) were good and similar to the correlation between TTE and cardiac catheterization (r = 0.88; p < 0.001; limits of agreement, ± 0.71 cm(2)). The best cutoff level for detecting moderate-to-severe stenosis at MDCT was an MVA of 1.70 cm(2), resulting in a sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 73%, 88%, 82%, 80%, and 83%, respectively, with two false-positive and three false-negative results. CONCLUSION: The MVA planimetrically determined by MDCT is systematically larger than those calculated by Doppler TTE and cardiac catheterization. However, because of a good correlation between methods and adjustment for the systematic bias, MDCT may allow reliable quantification of MVS and effectual discrimination among severity grades, although discrepancies between methods remain in individual cases.

Atypical presentation of a locally advanced hepatocellular carcinoma: Extensive workup of an incidental finding on computed tomography performed for planning of transcatheter aortic valve implantation.

This case report presents the diagnostic workup of liver malignancy incidentally detected in a 72-year-old male patient on routine body computed tomography angiography (CTA) performed for planning transcatheter aortic valve implantation (TAVI). The patient initially presented to an outside hospital with chest discomfort, where routine diagnostic procedures in the emergency room revealed grade III aortic valve stenosis. Routine CTA for TAVI planning in our department then revealed tumor thrombosis of the portal vein suspicious for hepatic malignancy. In contrast-enhanced ultrasound (CEUS) only the left hepatic lobe was inhomogeneously transformed with early arterial contrast enhancement. Magnetic resonance imaging (MRI) confirmed a primary hepatic malignancy involving the left liver. Transcutaneous biopsy with ultrasound guidance established the diagnosis of hepatocellular carcinoma (HCC). Incidental findings may be of prognostic relevance for the patient and in a number of cases, TAVI can be a prerequisite for the appropriate therapy.

Computed Tomography-Based Assessment of Transvalvular Pressure Gradient in Aortic Stenosis.

Background: In patients with aortic stenosis, computed tomography (CT) provides important information about cardiovascular anatomy for treatment planning but is limited in determining relevant hemodynamic parameters such as the transvalvular pressure gradient (TPG). Purpose: In the present study, we aimed to validate a reduced-order model method for assessing TPG in aortic stenosis using CT data. Methods: TPGCT was calculated using a reduced-order model requiring the patient-specific peak-systolic aortic flow rate (Q) and the aortic valve area (AVA). AVA was determined by segmentation of the aortic valve leaflets, whereas Q was quantified based on volumetric assessment of the left ventricle. For validation, invasively measured TPGcatheter was calculated from pressure measurements in the left ventricle and the ascending aorta. Altogether, 84 data sets of patients with aortic stenosis were used to compare TPGCT against TPGcatheter. Results: TPGcatheter and TPGCT were 50.6 ± 28.0 and 48.0 ± 26 mmHg, respectively (p = 0.56). A Bland-Altman analysis revealed good agreement between both methods with a mean difference in TPG of 2.6 mmHg and a standard deviation of 19.3 mmHg. Both methods showed good correlation with r = 0.72 (p < 0.001). Conclusions: The presented CT-based method allows assessment of TPG in patients with aortic stenosis, extending the current capabilities of cardiac CT for diagnosis and treatment planning.

Feasibility of contrast material volume reduction in coronary artery imaging using 320-slice volume CT.

OBJECTIVE: To assess reduced volumes of contrast agent on image quality for coronary computed tomography angiography (CCTA) by using single-beat cardiac imaging with 320-slice CT. MATERIALS AND METHODS: Forty consecutive male patients (mean age: 55.8 years) undergoing CCTA with body weight or=55% were included. Image acquisition protocol was standardized (120 kV, 400 mA, and prospective ECG-triggered single-beat nonspiral CCTA). Patients were randomly assigned to one of four groups (G1: received 40 ml, G2: 50 ml, G3: 60 ml, G4: 70 ml). Groups were compared with respect to aortic attenuation, image noise, and image quality. RESULTS: CT values (mean +/- standard deviation) in the aortic root were measured as 423 +/- 38 HU in G1, and 471 +/- 68, 463 +/- 60, and 476 +/- 78 HU in G2-4, respectively. There were no statistically significant differences in attenuation among the groups (P > 0.068). All 40 CT datasets were rated diagnostic, and image noise and image quality were not statistically different among groups. CONCLUSION: Using 320-slice volume CT, diagnostic image quality can be achieved with 40 ml of contrast material in CCTA in patients with normal body weight, cardiac function, and low heart rate.

Comparison of non-gated vs. electrocardiogram-gated 64-detector-row computed tomography for integrated electroanatomic mapping in patients undergoing pulmonary vein isolation.

AIMS: To compare non-gated vs. electrocardiogram (ECG)-gated 64-detector-row computed tomography (MDCT) of the left atrium (LA) for integrated electroanatomic mapping (EAM) in patients with paroxysmal atrial fibrillation (AF). METHODS AND RESULTS: Twenty-nine consecutive patients with paroxysmal AF underwent MDCT prior to pulmonary vein isolation (PVI). All patients were in sinus rhythm both during CT imaging and PVI. Multi-detector-row computed tomography was performed in 15 patients without ECG-gating (non-gated MDCT) and in 14 patients with retrospective ECG-gating (ECG-gated MDCT). Image quality of LA reconstructions from MDCT was rated on a five-point scale (from 1 = excellent to 5 = segmentation failed). Registration error between LA geometry obtained from EAM and MDCT was calculated as the mean distance between EAM points and MDCT surface. In all patients, LA was successfully segmented from MDCT data. The segmentation process took 2:31 +/- 0:54 min for non-gated MDCT and 2:36 +/- 0:47 min for ECG-gated MDCT (P = 0.8). Image quality scores of LA reconstructions from non-gated and ECG-gated MDCT were 1.3 +/- 0.6 and 1.4 +/- 0.7, respectively (P = 0.76). There was no significant difference in the registration error between non-gated and ECG-gated MDCT (1.8 +/- 0.2 vs. 1.9 +/- 0.3 mm, respectively; P = 0.6). The radiation dose of non-gated MDCT was significantly lower compared with ECG-gated MDCT (4.6 +/- 1.4 vs. 13.4 +/- 3.6 mSv, respectively; P < 0.001). CONCLUSION: Non-gated MDCT depicts LA with appropriate image quality for integrated EAM, while exposing patients to substantially lower radiation dose compared with ECG-gated MDCT.

Variability of semiautomated lung nodule volumetry on ultralow-dose CT: comparison with nodule volumetry on standard-dose CT.

The study investigates the effect of a substantial dose reduction on the variability of lung nodule volume measurements by assessing and comparing nodule volumes using a dedicated semiautomated segmentation software on ultralow-dose computed tomography (ULD-CT) and standard-dose computed tomography (SD-CT) data. In 20 patients, thin-slice chest CT datasets (1 mm slice thickness; 20% reconstruction overlap) were acquired at ultralow-dose (120 kV, 5 mAs) and at standard-dose (120 kV, 75 mAs), respectively, and analyzed using the segmentation software OncoTREAT (MeVis, Bremen, Germany; version 1.3). Interobserver variability of volume measurements of 202 solid pulmonary nodules (mean diameter 11 mm, range 3.2-44.5 mm) was calculated for SD-CT and ULD-CT. With respect to interobserver variability, the 95% confidence interval for the relative differences in nodule volume in the intrascan analysis was measured with -9.7% to 8.3% (mean difference -0.7%) for SD-CT and with -12.6% to 12.4% (mean difference -0.2%) for ULD-CT. In the interscan analysis, the 95% confidence intervals for the differences in nodule volume ranged with -25.1% to -23.4% and 26.2% to 28.9% (mean difference 1.4% to 2.1%) dependent on the combination of readers and scans. Intrascan interobserver variability of volume measurements was comparable for ULD-CT and SD-CT data. The calculated variability of volume measurements in the interscan analysis was similar to the data reported in the literature for CT data acquired with equal radiation dose. Thus, the evaluated segmentation software provides nodule volumetry that appears to be independent of the dose level with which the CT source dataset is acquired.