Michael Hanley

Coronary microvascular dysfunction is related to abnormalities in myocardial structure and function in cardiac amyloidosis.

OBJECTIVES The purpose of this study was to test the hypothesis that coronary microvascular function is impaired in subjects with cardiac amyloidosis. BACKGROUND Effort angina is common in subjects with cardiac amyloidosis, even in the absence of epicardial coronary artery disease (CAD). METHODS Thirty-one subjects were prospectively enrolled in this study, including 21 subjects with definite cardiac amyloidosis without epicardial CAD and 10 subjects with hypertensive left ventricular hypertrophy (LVH). All subjects underwent rest and vasodilator stress N-13 ammonia positron emission tomography and 2-dimensional echocardiography. Global left ventricular myocardial blood flow (MBF) was quantified at rest and during peak hyperemia, and coronary flow reserve (CFR) was computed (peak stress MBF/rest MBF) adjusting for rest rate pressure product. RESULTS Compared with the LVH group, the amyloid group showed lower rest MBF (0.59 ± 0.15 ml/g/min vs. 0.88 ± 0.23 ml/g/min; p = 0.004), stress MBF (0.85 ± 0.29 ml/g/min vs. 1.85 ± 0.45 ml/g/min; p < 0.0001), and CFR (1.19 ± 0.38 vs. 2.23 ± 0.88; p < 0.0001) and higher minimal coronary vascular resistance (111 ± 40 ml/g/min/mm Hg vs. 70 ± 19 ml/g/min/mm Hg; p = 0.004). Of note, almost all subjects with amyloidosis (>95%) had significantly reduced peak stress MBF (<1.3 ml/g/min). In multivariable linear regression analyses, a diagnosis of amyloidosis, increased left ventricular mass, and age were the only independent predictors of impaired coronary vasodilator function. CONCLUSIONS Coronary microvascular dysfunction is highly prevalent in subjects with cardiac amyloidosis, even in the absence of epicardial CAD, and may explain their anginal symptoms. Further study is required to understand whether specific therapy directed at amyloidosis may improve coronary vasomotion in amyloidosis.

Computed tomography angiography and magnetic resonance angiography imaging of the mesenteric vasculature.

Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are highly accurate cross-sectional vascular imaging modalities that have almost completely replaced diagnostic catheter angiography for the evaluation of the mesenteric vasculature. CTA is the technique of choice when evaluating patients with suspected mesenteric ischemia; it permits to differentiate between occlusive and nonocclusive etiologies, to evaluate indirect signs of bowel ischemia, and in some instances, to provide alternative diagnoses. MRA has the advantage of not using ionizing radiation and iodinated contrast agents and can be appropriate in the nonacute setting. Both CTA and MRA are suitable for the assessment of patients with suspected chronic mesenteric ischemia, allowing to evaluate the degree of atherosclerotic steno-occlusive disease and the existence of collateral circulation, as well as other nonatherosclerotic vascular pathologies such as fibromuscular dysplasia and median arcuate ligament syndrome. CTA provides excellent depiction of visceral aneurysms and has an important role to plan therapy for both occlusive and aneurysmal diseases and in the follow-up of patients after open or endovascular mesenteric revascularization procedures. This article provides an introduction to the CTA and MRA imaging protocol to study the mesenteric vasculature, the imaging findings in patients presenting with acute and chronic mesenteric ischemia and visceral aneurysms, and the value of these imaging techniques for therapy planning and follow-up.

Volumetric Quantification of Type II Endoleaks: An Indicator for Aneurysm Sac Growth Following Endovascular Abdominal Aortic Aneurysm Repair

Delayed enhanced phase CT images can be used to perform volumetric quantification of type II endoleak cavities, a parameter that can be used to indicate which aneurysm sac will enlarge and which will be stable or shrink at follow-up CT.

ACR Appropriateness Criteria® Imaging for Transcatheter Aortic Valve Replacement

Although aortic valve replacement is the definitive therapy for severe aortic stenosis, almost half of patients with severe aortic stenosis are unable to undergo conventional aortic valve replacement because of advanced age, comorbidities, or prohibitive surgical risk. Treatment options have been recently expanded with the introduction of catheter-based implantation of a bioprosthetic aortic valve, referred to as transcatheter aortic valve replacement. Because this procedure is characterized by lack of exposure of the operative field, image guidance plays a critical role in preprocedural planning. This guideline document evaluates several preintervention imaging examinations that focus on both imaging at the aortic valve plane and planning in the supravalvular aorta and iliofemoral system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

ACR Appropriateness Criteria Imaging in the Diagnosis of Thoracic Outlet Syndrome

Thoracic outlet syndrome is a clinical entity characterized by compression of the neurovascular bundle, and may be associated with additional findings such as venous thrombosis, arterial stenosis, or neurologic symptoms. The goal of imaging is to localize the site of compression, the compressing structure, and the compressed organ or vessel, while excluding common mimics. A literature review is provided of current indications for diagnostic imaging, with discussion of potential limitations and benefits of the respective modalities. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. In this document, we provided guidelines for use of various imaging modalities for assessment of thoracic outlet syndrome.

ACR Appropriateness Criteria® nontraumatic aortic disease.

The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. In this document we provided guidelines for use of various imaging modalities for assessment of nontraumatic aortic diseases.

ACR Appropriateness Criteria® Renovascular Hypertension

Renovascular hypertension is the most common type of secondary hypertension and is estimated to have a prevalence between 0.5% and 5% of the general hypertensive population, and an even higher prevalence among patients with severe hypertension and end-stage renal disease, approaching 25% in elderly dialysis patients. Investigation for renal artery stenosis is appropriate when clinical presentation suggests secondary hypertension rather than primary hypertension, when there is not another known cause of secondary hypertension, and when intervention would be carried out if a significant renal artery stenosis were identified. The primary imaging modalities used to screen for renal artery stenosis are CT, MRI, and ultrasound, with the selection of imaging dependent in part on renal function. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Computed tomography angiography gravitational gradient as an imaging sign of slow flow

Abstract Intraluminal layering of iodinated contrast on a single axial computed tomography image is described as a possible sign of slow arterial flow and is quantified using a new region of interest–based metric, that is, gravitational gradient. The metric was measured in 4 patients who demonstrated this phenomenon and in the aorta of 10 patients with no clinical sign suggestive of slow flow. Future studies are needed to validate the relationship between gravitational gradient, slow flow, and patient outcome.

ACR Appropriateness Criteria® Thoracic Aorta Interventional Planning and Follow-Up

Thoracic endovascular aortic repair (TEVAR) has undergone rapid evolution and is now applied to a range of aortic pathologies. Imaging plays a vital role in the pre- and postintervention assessment of TEVAR patients. Accurate characterization of pathology and evaluation for high-risk anatomic features are necessary in the planning phase, and careful assessment for graft stability, aortic lumen diameter, and presence of endoleak are paramount in the follow-up period. CTA is the imaging modality of choice for pre- and postintervention assessment, and MRA is an acceptable alternative depending on patient stability and graft composition. Lifelong imaging follow-up is necessary in TEVAR patients because endoleaks may develop at any time. The exact surveillance interval is unclear and may be procedure and patient specific. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Penetrating Neck Injury

In patients with penetrating neck injuries with clinical soft injury signs, and patients with hard signs of injury who do not require immediate surgery, CT angiography of the neck is the preferred imaging procedure to evaluate extent of injury. Other modalities, such as radiography and fluoroscopy, catheter-based angiography, ultrasound, and MR angiography have their place in the evaluation of the patient, depending on the specific clinical situation and question at hand. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.