Preprocedural CT evaluation of transcatheter aortic valve replacement: what the radiologist needs to know.

Aortic valve stenosis is the most common valvular heart disease in the Western world. When symptomatic, aortic valve stenosis is a debilitating disease with a dismal short-term prognosis, invariably leading to heart failure and death. Elective surgical valve replacement has traditionally been considered the standard of care for symptomatic aortic valve stenosis. However, several studies have identified various subgroups of patients with a significantly elevated risk for surgery-related complications and death. Thus, not every patient is a suitable candidate for surgery. Recent developments in transcatheter-based therapies have provided an alternative therapeutic strategy for the nonsurgical patient population known as transcatheter aortic valve replacement (TAVR) (also called transcatheter aortic valve implantation or percutaneous aortic valve replacement). In TAVR, the native aortic valve is replaced with a bioprosthetic valve via a nonsurgical endovascular, transaortic, or transapical pathway. Nevertheless, several anatomic and technical criteria must be met to safeguard patient eligibility and procedural success. Therefore, noninvasive imaging plays a crucial role in both patient selection and subsequent matching to a specific transcatheter valve size in an effort to ensure accurate prosthesis deployment and minimize peri- and postprocedural complications. The authors review the relevant anatomy of the aortic root, emphasizing the implications of anatomic pitfalls for correct reporting of imaging-derived measurements and important differences between findings obtained with different imaging modalities. They also discuss the evolving role of computed tomography and the role of the radiologist in patient triage in light of current viewpoints regarding patient selection, device size selection, and the preprocedural evaluation of possible access routes. Online supplemental material is available for this article.

Transcatheter aortic valve replacement: postoperative CT findings of Sapien and CoreValve transcatheter heart valves.

Transcatheter aortic valve replacement represents one of the most exciting medical technical developments in recent years, offering a much-needed therapeutic alternative for patients with severe aortic valve stenosis who, due to comorbidities and advanced age, are considered to be inoperable or at high surgical risk. The efficacy of this procedure compared with standard surgical intervention has been properly validated in multicenter randomized controlled trials (PARTNER A and B trials), leading to widespread clinical implementation, with over 50,000 procedures currently being performed worldwide each year. Although much of the attention has rightly focused on the potential role of computed tomography (CT) in the preprocedural assessment of the aortic root and the establishment of imaging-guided valve-sizing algorithms, less is known regarding the postprocedural CT characteristics of transcatheter heart valves (THVs). However, given the increasing worldwide recognition and clinical implementation of these devices, they will no doubt be encountered with increasing frequency in patients referred for thoracic CT, either for postprocedural evaluation of the aortic root or for unrelated reasons. Familiarity with these devices and their CT characteristics will increase diagnostic confidence and the value of the radiology report. The authors describe the physical and imaging properties of the currently commercially available THVs, their normal postprocedural imaging appearances, and potential complications that can be detected at CT. In addition, they discuss the relative strengths and weaknesses of CT and echocardiography in this setting.

Multi-slice computed tomography with N1177 identifies ruptured atherosclerotic plaques in rabbits.

Rupture-prone and ruptured plaques are characterized by the presence of large numbers of macrophages. N1177 is a contrast agent consisting of iodinated nanoparticles that are selectively phagocytosed by macrophages. The aim of this study was to investigate the effect of N1177 on the CT attenuation of rupture-prone and ruptured plaques in rabbits. In addition, we examined in vitro whether uptake of N1177 occurred without cytotoxic or pro-inflammatory effects on macrophages. In vitro, the viability of J774 macrophages was not affected by treatment with N1177. Moreover, N1177 had no effect on the phagocytic capacity or cytokine production of macrophages. For the in vivo experiments, 6 New Zealand White rabbits were fed a cholesterol-supplemented diet for 12-15 months, resulting in the development of large atherosclerotic plaques that resembled rupture-prone plaques in humans. In three rabbits, mechanical plaque rupture was induced by retrograde pullback of an embolic protection device. N1177 had no effect on the median density of rupture-prone plaques [35 HU (range 3-85) before injection vs. 32 HU (range 1-93) 2 h after injection of N1177; P > 0.05]. However, after induction of mechanical plaque rupture, the median density of the atherosclerotic plaques increased from 40 HU (range 6-86) before injection to 74 HU (range 14-111) 2 h after injection of N1177 (P < 0.001). Using time-of-flight static secondary ion mass spectrometry, the presence of N1177 nanoparticles was demonstrated in macrophage-rich areas of ruptured plaques, but not of non-ruptured plaques. In conclusion, our results show that N1177 is a contrast agent that can identify ruptured atherosclerotic plaques.

Left atrial calcifications: computed tomographic imaging findings of an unusual sign of rheumatic heart disease.

Left atrial wall calcifications are an extremely rare finding of unknown cause usually associated with rheumatic disease. Only a few case reports of this entity are found in the literature, mostly describing the findings on conventional chest radiography, echocardiography, and angiography. To the best of our knowledge, this is the first case documented with multislice computed tomography.

CT imaging features of atrioventricular shunts: what the radiologist must know.

UNLABELLED: In the last decade, cardiac computed tomography (CT) has gained mainstream acceptance for the noninvasive exclusion of significant coronary disease in a selected population. Improvements in electrocardiogram (ECG)-triggered imaging techniques also allow, by extension, a proper evaluation of the complete heart anatomy. Given the increasing worldwide clinical implementation of cardiac CT for coronary artery evaluation, radiologists can, incidentally, be confronted with unfamiliar and previously unsuspected non-coronary cardiac pathologies, including congenital morphological defects. This presence of congenital heart disease (CHD) should not be overlooked, being the most common form of birth defect, with a total birth prevalence of 9.1 per 1000 live births worldwide [1]. The prevalence of adult patients with CHD is estimated to be 3000 per million adults [2]. Ventricular septal defects (VSDs) are the most frequent subtypes of CHD, accounting together with atrial septal defects (ASDs) for nearly half of all CHD cases [1]. While some small defects are rarely symptomatic and can go undetected for life, others are clinically significant and require adequate and timely medical intervention. In this article, we present the CT imaging features of atrioventricular (AV) shunts, highlighting both their embryological origins and associated relevant clinical features. TEACHING POINTS: • Congenital heart disease (CHD) is the most common birth defect. • Ventricular and atrial septal defects account for nearly half of CHD cases. • Atrioventricular defects can frequently be detected on a cardiac CT. • Radiologists must be able to identify clinically significant atrioventricular defects.

[Conservative treatment of a chronic rupture of Achilles tendon: case report]. / Tratamiento conservador de rotura crónica de tendón de Aquiles: reporte de caso.

We report a case of a 64 years-old-female patient with ruptured left Achilles tendon within two months of evolution that has gone unnoticed. By the application of a conservative treatment recovered complete and symmetrical functionality in five months time after the injury.

Presentamos el caso clínico de una paciente de 64 años con rotura de tendón de Aquiles izquierdo y dos meses de evolución que ha pasado desapercibida. Con la aplicación de un tratamiento conservador se consiguió una funcionalidad completa y simétrica a cinco meses de la lesión.

An evaluation of automatic coronary artery calcium scoring methods with cardiac CT using the orCaScore framework.

PURPOSE: The amount of coronary artery calcification (CAC) is a strong and independent predictor of cardiovascular disease (CVD) events. In clinical practice, CAC is manually identified and automatically quantified in cardiac CT using commercially available software. This is a tedious and time-consuming process in large-scale studies. Therefore, a number of automatic methods that require no interaction and semiautomatic methods that require very limited interaction for the identification of CAC in cardiac CT have been proposed. Thus far, a comparison of their performance has been lacking. The objective of this study was to perform an independent evaluation of (semi)automatic methods for CAC scoring in cardiac CT using a publicly available standardized framework. METHODS: Cardiac CT exams of 72 patients distributed over four CVD risk categories were provided for (semi)automatic CAC scoring. Each exam consisted of a noncontrast-enhanced calcium scoring CT (CSCT) and a corresponding coronary CT angiography (CCTA) scan. The exams were acquired in four different hospitals using state-of-the-art equipment from four major CT scanner vendors. The data were divided into 32 training exams and 40 test exams. A reference standard for CAC in CSCT was defined by consensus of two experts following a clinical protocol. The framework organizers evaluated the performance of (semi)automatic methods on test CSCT scans, per lesion, artery, and patient. RESULTS: Five (semi)automatic methods were evaluated. Four methods used both CSCT and CCTA to identify CAC, and one method used only CSCT. The evaluated methods correctly detected between 52% and 94% of CAC lesions with positive predictive values between 65% and 96%. Lesions in distal coronary arteries were most commonly missed and aortic calcifications close to the coronary ostia were the most common false positive errors. The majority (between 88% and 98%) of correctly identified CAC lesions were assigned to the correct artery. Linearly weighted Cohen's kappa for patient CVD risk categorization by the evaluated methods ranged from 0.80 to 1.00. CONCLUSIONS: A publicly available standardized framework for the evaluation of (semi)automatic methods for CAC identification in cardiac CT is described. An evaluation of five (semi)automatic methods within this framework shows that automatic per patient CVD risk categorization is feasible. CAC lesions at ambiguous locations such as the coronary ostia remain challenging, but their detection had limited impact on CVD risk determination.

Brachiocephalic artery access in transcatheter aortic valve implantation: a valuable alternative: 3-year institutional experience.

OBJECTIVES: With the expanding use of transcatheter aortic valve implantation (TAVI), we have encountered increasing numbers of patients without ideal femoral access. Although many alternatives have been described, vascular access and access-related complications remain a point of concern. We report our series of 20 patients undergoing TAVI via brachiocephalic artery access. METHODS: Between September 2011 and May 2014, we performed 107 consecutive CoreValve bioprosthesis implantations, of which 20 were by the brachiocephalic approach due to unfavourable iliac or femoral anatomy. RESULTS: No vascular or access-related complications were seen. Procedural feasibility, device success and early safety, as defined by the Valve Academic Research Consortium-2 criteria, were good, at 100, 95 and 95%, respectively. No stroke, transient ischaemic attack, acute kidney injury, major vascular or major bleeding complications were observed. At a mean follow-up of 497 days, the 1-year survival rate is 75.0%. Echocardiography at discharge confirmed moderate paravalvular regurgitation in 1 patient and mild paravalvular leakage in 3 patients, and no paravalvular leak more than moderate was seen. Echocardiography at discharge, 6 months and 1 year after TAVI confirmed persistent low mean transvalvular gradients (9, 9 and 10 mmHg, respectively). CONCLUSIONS: TAVI implantation through the brachiocephalic artery is safe and feasible. The distance between the point of access and the aortic valve annulus is short, improving catheter stability and implant site accuracy. We consider it to be a valuable alternative in patients without femoral access.

Multislice cardiac computed tomography in symptomatic middle-aged women.

OBJECTIVE: To assess the accuracy of multislice cardiac computed tomography (MSCT) for detection of significant coronary artery disease (CAD) in middle-aged symptomatic women. METHODS: We included 70 women (51+/-8 years) with complaints of chest pain or dyspnea, and an abnormal maximum exercise electrocardiogram (ECG) (8.6+/-1.4 metabolic equivalents). All had a MSCT using a 16 detector rows scanner, and coronary arteriography (CA). Blinded results of the two modalities were compared using a segment, vessel, and patient-based analysis. RESULTS: On MSCT 36% had normal coronaries, 24% had significant CAD requiring revascularization, and the remainder had mild CAD. MSCT had reasonably high diagnostic accuracy at segment level (negative predictive value of 95%, positive predictive value 81%, specificity 99%, and sensitivity 50%), regarding single or multivessel CAD when both nonassessable and assessable segments were included in the analysis. The agreement between the segments comparing MSCT and CA for significant CAD was excellent at 98% (kappa value 0.89). CONCLUSIONS: In this cohort of middle-aged symptomatic women with an abnormal stress test, 24% had significant CAD requiring intervention. MSCT was highly accurate in diagnosing significant CAD with an excellent negative predictive value.

Malignant pleural mesothelioma with heterologous osteoblastic elements: computed tomography, magnetic resonance, and positron emission tomography imaging characteristics of a rare tumor.

The imaging findings of a rare mixed type of malignant mesothelioma of the pleura with heterologous bone stroma in a patient without a previous history of asbestos exposure are reported. Imaging findings of this type of bone-forming pleural mesothelioma are scarcely reported in the literature, with only a few case reports describing findings on conventional radiography, computed tomography, and magnetic resonance imaging. To the best of our knowledge, no positron emission tomography imaging characteristics of this type of mesothelioma have been previously reported.