Should We Quantify Valvular Calcifications on Cardiac CT in Patients with Infective Endocarditis?

BACKGROUND: Evaluate the impact of valvular calcifications measured on cardiac computed tomography (CCT) in patients with infective endocarditis (IE). METHODS: Seventy patients with native IE (36 aortic IE, 31 mitral IE, 3 bivalvular IE) were included and explored with CCT between January 2016 and April 2018. Mitral and aortic valvular calcium score (VCS) were measured on unenhanced calcium scoring images, and correlated with clinical, surgical data, and 1-year death rate. RESULTS: VCS of patients with mitral IE and no peripheral embolism was higher than those with peripheral embolism (868 (25-1725) vs. 6 (0-95), p < 0.05). Patients with high calcified mitral IE (mitral VCS > 100; n = 15) had a lower rate of surgery (40.0% vs.78.9%; p = 0.03) and a higher 1-year-death risk (53.3% vs. 10.5%, p = 0.04; OR = 8.5 (2.75-16.40) than patients with low mitral VCS (n = 19). Patients with aortic IE and high aortic calcifications (aortic VCS > 100; n = 18) present more frequently atypical bacteria on blood cultures (33.3% vs. 4.8%; p = 0.03) than patients with low aortic VCS (n = 21). CONCLUSION: The amount of valvular calcifications on CT was associated with embolism risk, rate of surgery and 1-year risk of death in patients with mitral IE, and germ's type in aortic IE raising the question of their systematic quantification in native IE.

Diagnostic Value of Extracellular Volume Quantification and Myocardial Perfusion Analysis at CT in Cardiac Amyloidosis.

Background CT can provide information regarding myocardial perfusion and expansion of the extracellular space, which is relevant to patients with cardiac amyloidosis (CA). Purpose To evaluate the role of CT in the diagnosis and prognosis of CA. Materials and Methods In this prospective study (Commission National de l'Informatique et des Libertés registration no. 1431858), participants with CA, participants with nonamyloid cardiac hypertrophy (NACH), and participants without hypertrophy were included between April 2017 and December 2018. The confirmed diagnosis of CA was determined according to established criteria (ie, proven with positive bone scintigraphy or endomyocardial biopsy). All participants were imaged with dynamic CT perfusion imaging at whole-heart cardiac CT. Extracellular volume measured at CT and myocardial perfusion parameters calculated on CT perfusion maps were compared among different participant groups. Differences between continuous data were tested using the unpaired t test, Mann-Whitney rank-sum test, or the Kruskal-Wallis test. Results A total of 84 participants with CA, 43 participants with NACH, and 33 participants without hypertrophy were included. Participants with CA exhibited a higher value of extracellular volume measured at CT (mean, 54.7% ± 9.7 [standard deviation]) than participants with NACH (mean, 34.6% ± 9.1; P < .001) and participants without hypertrophy (mean, 35.9% ± 9.9; P = .001). Mean myocardial blood volume and mean myocardial blood flow were lower in participants with CA (mean myocardial blood volume: 4.05 mL/100 g of myocardium ± 0.80; mean myocardial blood flow: 73.2 mL/100 g of myocardium per minute ± 25.7) compared to participants with NACH (mean myocardial blood volume: 5.38 mL/100 g of myocardium ± 1.20, P < .001; mean myocardial blood flow: 89.6 mL/100 g of myocardium per minute ± 31.3, P = .007) and participants without hypertrophy (mean myocardial blood volume: 5.68 mL/100 g of myocardium ± 1.05; mean myocardial blood flow: 106.3 mL/100 g of myocardium per minute ± 29.8; P < .001 for both). Extracellular volume measured at CT (hazard ratio >0.56 vs ≤0.56 = 4.2 [95% CI: 1.4, 11.8]), mean slope (hazard ratio ≤3.0 sec-1 vs >3.0 sec-1 = 0.2 [95% CI: 0.1, 0.8]), and time to peak (hazard ratio >20 seconds vs ≤20 seconds = 11.6 [95% CI: 1.3, 101.6]) were predictive of mortality in participants with CA. Conclusion Participants with cardiac amyloidosis exhibited an increase in extracellular volume at CT and abnormal CT perfusion parameters. Extracellular volume and several perfusion parameters were predictive of mortality. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Zimmerman in this issue.

Risk factors for passive anterior tibial subluxation on MRI in complete ACL tear.

INTRODUCTION: In anterior cruciate ligament (ACL) tear, passive spontaneous anterior tibial subluxation (ATS), with respect to the femur, is sometimes observed on MRI. In a case-control study, ATS>3.5mm showed 100% specificity (±3.6, 95% CI) for complete ACL tear. The aim of the present study was to assess the relation between ATS on MRI and associated lesions in complete ACL tear. The study hypothesis was that associated lesions are a risk factor for ATS. MATERIAL AND METHODS: A retrospective study included patients operated on for complete ACL tear between 2010 and 2015. Exclusion criteria comprised associated posterior cruciate ligament tear, partial ACL tear, and history of knee surgery. Preoperative MRI was performed with the patient in supine position and the knee in 20° flexion in neutral rotation. ATS was measured by axial superimposition of the bicondylar slice on the slice through the tibial plateau. Associated lesions were assessed: medial and lateral menisci, collateral ligaments, posteromedial and posterolateral corners, tibiofemoral compartment cartilage and cancellous bone. Factors associated with ATS>3.5mm were analyzed. Ninety-one patients were included: mean age, 31.1±10.1 years; 34 female, 57 male. Mean time from injury to MRI was 7.8±11.7 months (range, 0.7-60 months). RESULTS: Mean ATS was 4.7±2.3mm. Inter- and intra-observer reproducibility for ATS measurement were excellent. On preoperative MRI, 61.1% of patients showed bone edema, 48.4% medial meniscal tear, and 36.3% lateral meniscal tear. ATS was significantly greater in case of medial meniscal tear (5.4±2.3mm vs. 4±2.1mm; p=0.003). No significant differences were found according to other lesions. Fifty-four patients (59.3%) showed ATS>3.5mm; risk factors comprised medial meniscal tear (OR=2.6, 95%CI [1.1-6.2]; p=0.03) and injury-to-MRI time>9 months (OR=9.8, 95% CI [1.1-85.2]; p=0.04). CONCLUSION: Spontaneous anterior tibial subluxation on MRI in complete ACL tear was significantly associated with medial meniscal tear and accident-to-MRI time. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Rapid Contour-based Segmentation for 18F-FDG PET Imaging of Lung Tumors by Using ITK-SNAP: Comparison to Expert-based Segmentation.

Purpose To assess the performance of the ITK-SNAP software for fluorodeoxyglucose (FDG) positron emission tomography (PET) segmentation of complex-shaped lung tumors compared with an optimized, expert-based manual reference standard. Materials and Methods Seventy-six FDG PET images of thoracic lesions were retrospectively segmented by using ITK-SNAP software. Each tumor was manually segmented by six raters to generate an optimized reference standard by using the simultaneous truth and performance level estimate algorithm. Four raters segmented 76 FDG PET images of lung tumors twice by using ITK-SNAP active contour algorithm. Accuracy of ITK-SNAP procedure was assessed by using Dice coefficient and Hausdorff metric. Interrater and intrarater reliability were estimated by using intraclass correlation coefficients of output volumes. Finally, the ITK-SNAP procedure was compared with currently recommended PET tumor delineation methods on the basis of thresholding at 41% volume of interest (VOI; VOI41) and 50% VOI (VOI50) of the tumor's maximal metabolism intensity. Results Accuracy estimates for the ITK-SNAP procedure indicated a Dice coefficient of 0.83 (95% confidence interval: 0.77, 0.89) and a Hausdorff distance of 12.6 mm (95% confidence interval: 9.82, 15.32). Interrater reliability was an intraclass correlation coefficient of 0.94 (95% confidence interval: 0.91, 0.96). The intrarater reliabilities were intraclass correlation coefficients above 0.97. Finally, VOI41 and VOI50 accuracy metrics were as follows: Dice coefficient, 0.48 (95% confidence interval: 0.44, 0.51) and 0.34 (95% confidence interval: 0.30, 0.38), respectively, and Hausdorff distance, 25.6 mm (95% confidence interval: 21.7, 31.4) and 31.3 mm (95% confidence interval: 26.8, 38.4), respectively. Conclusion ITK-SNAP is accurate and reliable for active-contour-based segmentation of heterogeneous thoracic PET tumors. ITK-SNAP surpassed the recommended PET methods compared with ground truth manual segmentation.

Myocardial iodine concentration measurement using dual-energy computed tomography for the diagnosis of cardiac amyloidosis: a pilot study.

OBJECTIVE: To measure myocardium iodine concentration (MIC) in patients with cardiac amyloidosis (CA) using dual-energy computed tomography (DECT). METHODS: Twenty-two patients with CA, 13 with non-amyloid hypertrophic cardiomyopathies (CH) and 10 control patients were explored with pre-contrast, arterial and 5-minute DECT acquisition (Iomeprol; 1.5 mL/kg). Inter-ventricular septum (IVS) thickness, blood pool iodine concentration (BPIC), MIC (mg/mL), iodine ratio and extra-cellular volume (ECV) were calculated. RESULTS: IVS thickness was significantly (p < 0.001) higher in CA (17 ± 4 mm) and CH (15 ± 3 mm) patients than in control patients (10 ± 1 mm). CA patients exhibited significantly (p < 0.001) higher 5-minute MIC [2.6 (2.3-3.1) mg/mL], 5-minute iodine ratio (0.88 ± 0.12) and ECV (0.56 ± 0.07) than CH [1.7 (1.4-2.2) mg/mL, 0.57 ± 0.07 and 0.36 ± 0.05, respectively] and control patients [1.9 (1.7-2.4) mg/mL, 0.58 ± 0.07 and 0.35 ± 0.04, respectively). CH and control patients exhibited similar values (p = 0.9). The area under the curve of 5-minute iodine ratio for the differential diagnosis of CA from CH patients was 0.99 (0.73-1.0; p = 0.001). With a threshold of 0.65, the sensitivity and specificity of 5-minute iodine ratio were 100% and 92%, respectively. CONCLUSION: Five-minute MIC and iodine ratio were increased in CA patients and exhibited best diagnosis performance to diagnose CA in comparison to other parameters. KEY POINT: • Dual-energy computed tomography can be used to detect cardiac amyloidosis • Five-minute myocardial iodine concentration and iodine ratio increase in cardiac amyloidosis • Among iodine parameters, 5-minute iodine ratio has the best diagnosis performance.