Search

We compared the variance of area and diameter significant stenosis measurement between quantitative computed tomography coronary angiography (QCTA) and quantitative invasive coronary angiography (QCA). Fifty patients presenting 65 significant coronary artery stenoses (≥70% area stenosis) in QCTA and QCA were included. Spearman's rank correlation revealed that area stenosis measurement by QCTA and QCA yields higher correlation than diameter stenosis and is highest for noncalcified and mixed lesions.

Noninvasive visualization of the coronary arteries is the holy grail of cardiac imaging. Cardiac catheterization, the historic gold standard for coronary imaging, is invasive, costly, and often performed unnecessarily. Cardiac computed tomographic angiography (CCTA) is a widely available, cost-effective imaging modality that effectively images the coronary arteries. The most appropriate patient for a CCTA-guided approach to the evaluation of chest pain is the symptomatic patient at low to intermediate risk. Data are rapidly evolving to further validate the accuracy, prognostic ability, and cost-effectiveness of this technique. The current landscape of the American medical system and the rising cost of United States health care have led to skepticism concerning CCTA and its potential misuse. Technological misunderstanding and concern about excessive radiation exposure also threaten its growth. When used properly by appropriately trained physicians, CCTA adds significant value to the evaluation of chest pain and to the diagnosis of coronary artery disease.

In this chapter, the diagnostic performance of cardiac CT angiography (CCTA) is highlighted and its accuracy is discussed. In addition, the prognostic value of CCTA is examined. The major research trials are discussed and highlighted and put into context for the reader. The implication of a zero calcium score is also detailed.

An understanding of radiation and radiation safety are critical to proper comprehension of cardiac CT angiography (CCTA). This chapter focuses on the important concepts relating to radiation and radiation safety. Important terms, concepts and definitions pertaining to radiation in general and to its application to CCTA are reviewed. The chapter discusses how x rays are produced and utilized by the CT scanner. Radiation dosing and its long term affects are reviewed. Techniques to reduce radiation by CCTA are detailed. Upon completion of this chapter, the reader will be proficient in the general concepts, terms and definitions of radiation in general and radiation as it pertains to CCTA. The reader will understand how to limit radiation exposure while still obtaining a diagnostic CCTA.

In this chapter, the art of performing a cardiac CT angiography (CCTA) examination is reviewed. Tips and tricks to be successful are discussed. The nuts and bolts of how to perform this highly technical exam are highlighted. Laboratory and training requirements are also detailed. The reader is taught how to read a CCTA study and one structured, formalized approach is outlined. The author’s experience in reading CCTA is brought to the forefront in providing specific details on specifically how to accomplish a successful, accurate and clinically useful read. Tips on how to manipulate the workstation are reviewed. The requirements for a structured report are discussed in detail and an example of one, accepted, structured report is provided.

In this chapter, the basics of CT physics and CT technology are reviewed in detail. The reader will gain a complete understanding of how a CT scanner functions and will become familiar with the terms and definitions important to a working understanding of the science of computed tomography. The workings of the x ray source, the CT detectors and the gantry are reviewed. The concepts related to multidetector CT are detailed in depth to allow the reader to comprehend multislice CT which is necessary for modern cardiac computed tomography angiography (CCTA) application. The reader is taken through all of the necessary steps from start to finish that are necessary to generate a CCTA image. Image reconstruction techniques are also reviewed in depth to allow the reader to understand the concepts necessary to properly and efficiently interpret a CCTA data set. Finally, important, specific CCTA terms and definitions are explained so that the reader will gain an in depth understanding of these sometimes nebulous concepts.

This chapter is a detailed review of the principles specific to cardiac CT angiography (CCTA) which is a highly specialized form of CT in general. The reader is thoroughly introduced to important concepts in data acquisition and the particulars important to acquiring useful information that will be used to create the CCTA image, which include patient selection and preparation, CCTA protocols and scan timing, radiation sparing techniques and contrast and contrast injection principles. Data reconstruction is reviewed in detail, including phase selection, reconstruction filters and electrocardiogram editing. Additionally, image display formats are detailed including volume rendered techniques, maximum intensity projections, multiplanar reformats and curved multiplanar reformats. By the end of this chapter, the reader will be proficient in CCTA data acquisition, reconstruction and image display.

This chapter highlights useful, specific applications of cardiac CT angiography (CCTA) and reviews them in detail. First, CCTA for chest pain in the emergency department is reviewed and the data to support its use is detailed. Next, the evaluation of bypass grafts is discussed and the strengths and weaknesses of CCTA for this indication are reviewed. The imaging of coronary stents using CCTA is addressed next. A thoughtful discussion of its limitations are reviewed. CCTA for plaque characterization is then discussed and its limitations and future directions are highlighted. Plaque characteristics suggestive of high risk are introduced and CCTA for the physiologic evaluation of coronary stenoses is discussed, including stress CCTA and the noninvasive measurement of fractional flow reserve using CCTA. CCTA for the detection of myocardial infarction is also included. The assessment of cardiac valves using CCTA is detailed, including the use of CCTA for transcatheter aortic valve replacement (TAVR) planning. CCTA for the assessment of prosthetic heart valves is also discussed. Electrophysiology applications for CCTA, including the use of CCTA for atrial fibrillation ablation planning and follow up, and for guidance for the placement of biventricular pacemakers is detailed. Finally, CCTA in the evaluation of cardiac source of embolism and for the evaluation and characterization of coronary anomalies is included.

Systemic artery-to-pulmonary artery shunts are palliative surgical procedures performed to increase the blood flow to the lungs for the relief of cyanosis and to enlarge the pulmonary arteries. Palliative procedures improve oxygen saturation, but they also can result in volume loading of the systemic ventricle and possible pulmonary hypertension.

Coronary artery anomalies represent a heterogeneous group of congenital disorders with different pathophysiology and clinical impact. By definition, they represent variants or deviations from the normal coronary artery anatomy [1].

Congenital absence of the pericardium is an abnormality characterized by a spectrum of findings ranging from a small defect to complete absence of the pericardium.

The heart lies in the middle mediastinum within the pericardial sac. The pericardial sac is formed by two layers: the outer layer known as the fibrous pericardium and the inner layer known as the serous pericardium. The serous pericardium contains two layers: visceral and parietal. The inner visceral layer covers the surface of heart and base of the great vessels. At the level of the great vessels, it reflects and becomes the parietal layer, which lines the thick fibrous pericardium. The fibrous pericardium fuses with the base of the great vessels and the diaphragm and it is attached to the sternum by the sternopericardial ligament.

The classic lesions of tetralogy of Fallot (TOF) include pulmonary stenosis, ventricular septal defect (VSD), overriding aorta, and right ventricular hypertrophy. The hemodynamically significant lesions are the VSD and pulmonary stenosis that results in right ventricular outflow tract (RVOT) obstruction. Originally, a two-stage repair was performed for repair of TOF. First pulmonary blood flow was increased with systemic-to-pulmonary artery shunts (classic and modified Blalock–Taussig shunt, Waterston shunt, or Potts shunt) followed by a complete repair when the child was older. Complications associated with this strategy include pulmonary hypertension and congestive heart failure from the augmented pulmonary blood flow and stenosis of the pulmonary artery at the anastomotic site.

Hypoplastic left heart syndrome (HLHS) is characterized by hypoplasia of the left heart and varying degrees of hypoplasia or atresia of the aortic valve and ascending aorta. It is included in the spectrum of conditions that can result in a cardiac circulation with a functionally single ventricle. Left untreated, HLHS is invariably lethal. Advances in palliative surgical procedures (Norwood procedure, bidirectional cavopulmonary shunt, modified Fontan procedure) have increased the survival rate in children with HLHS.

Univentricular heart, also termed “functionally single ventricle” and “single ventricle,” refers to the congenital heart defects in which the heart functionally has only one pumping chamber. The unifying criteria to identify a univentricular heart is a main (dominant) ventricle with a malformed atrioventricular connection and a rudimentary (incomplete) ventricle, which lacks an inlet component or less commonly an outlet component [1–4]. A true single ventricle is exceedingly rare.

The segmental, sequential, analytic approach was introduced by Van Praagh over 25 years ago [1–3]. This clinically useful approach is flexible and widely applicable to any imaging evaluation of congenital heart disease [4]. Using this logical approach, the morphologic features of the heart are determined sequentially by dividing the heart into three segments: visceroatrial situs or spatial arrangement (step 1), ventricular looping (step 2), and the spatial relationships of the great vessels (step 3). In step 4, the connections between the segments at the atrioventricular and ventriculoarterial levels are identified. Next, cardiac positioning is determined in step 5. Finally, step 6 involves the assessment for any associated malformation. See Fig. 5.1.

There are many not uncommonly seen variants that may be mistaken as abnormal, and recognition of these normal variants will increase diagnostic imaging accuracy and reduce the incidence of false alarms.

Until the mid-1990s, the standard surgical approach to repair congenitally corrected transposition of the great arteries was repair of the associated lesions (ventricular septal defect and pulmonary stenosis or atresia), allowing the right ventricle to remain as the systemic pump. Since this approach has a high prevalence of complications, surgical correction is now advocated in early childhood (several months to a few years of age). Correction is achieved with the double-switch procedure which uses a combination of the atrial switch and arterial switch surgeries previously described in Chaps. 23 and 24 [1–3]. Either a Mustard or Senning procedure is performed followed by either a Jatene switch or Rastelli-type procedure. The result of this operation is anatomically correct anatomy and removal of the systemic pressure load from the right ventricle. See Figs. 28.1 and 28.2.

Arterial switch (Jatene) procedure, which was developed in the late 1970s, is currently the method of choice for treatment of transposition of the great arteries (TGA). It reestablishes the left ventricle as a systemic pump, avoiding systemic ventricular failure associated with the atrial switch operation. This procedure is indicated for patients with TGA with an intact ventricular septum or with a small ventricular septal defect (VSD). Patients with large nonrestrictive VSDs, left ventricular outflow obstruction, or increased pulmonary vascular resistance may not be candidates for the arterial switch procedure.

The computed tomographic angiography (CTA) imaging protocol must be tailored to the suspected cardiac lesion and the type of prior surgical repair. The relevant parameters that need to be selected prior to imaging are contrast volume, contrast injection speed, the timing of the scan, slice collimation, scan length, tube voltage (kV), tube current (mA), and pitch. In addition, the imager must decide on the use of non-ECG-synchronized acquisition versus ECG synchronization (prospective or retrospective). In general, multidetector scanner with ≥64 rows is preferred for evaluation of congenital heart disease (CHD).

Aortic valve stenosis refers to a narrowing of the lumen of the aortic valve. It is the most common cardiac valvular condition requiring valve replacement. Congenital stenosis is the most common cause of aortic valve stenosis. It is usually associated with anomalous valves, most commonly the bicuspid aortic valve. The congenitally stenotic aortic valve also may be unicuspid (acommissural or unicommissural) or, rarely, congenitally quadricuspid/quadricommissural. A dysplastic tricuspid aortic valve can also develop stenosis (Fig. 13.1).

In a normal biventricular heart, the systemic and pulmonary circulations are in series and each circulation is supported by its respective ventricle. In patients with single ventricular chamber morphology, the two circulations are in parallel and patients only survive by mixing of the systemic and pulmonary venous blood, usually via a septal defect. Systemic venous to pulmonary artery surgical connections have been created to provide venous flow to the pulmonary circulation to allow oxygenation of the blood.

The Damus–Kaye–Stansel (DKS) operation is a palliative procedure for patients with a single functioning ventricle with an obstructed rudimentary outflow chamber. It is not used for treatment of hypoplastic left heart syndrome which is treated using the Norwood procedure. operation is used for in double-inlet left ventricle, tricuspid atresia with transposition of the great arteries (TGA), and a common atrioventricular canal with small left ventricular cavity.

Congenital pulmonary valve abnormalities encompass a spectrum of anomalies that result in right ventricular outflow tract (RVOT) obstruction. Based on the level of obstruction, there are three possible variants: (a) valvular, (b) subvalvular (infundibular stenosis), and (c) supravalvular.

Left ventricular noncompaction (LVNC), also called spongiform cardiomyopathy, is a rare congenital cardiomyopathy that results from interrupted cardiac embryogenesis. Pathologically, it is characterized by prominent trabeculations and deep intertrabecular recesses, creating a “spongy” myocardium. The cause is thought to be an arrest in the gradual compaction of the loosely interwoven meshwork of myocardial fibers during endomyocardial morphogenesis at 5–8 weeks of fetal life. The condition predominately affects the left ventricle (LV).

Tetralogy of Fallot (TOF) is characterized by four constant features: right ventricular outflow tract (RVOT) obstruction, malalignment (perimembranous) ventricular septal defect (VSD), biventricular origin of the aorta (overriding aorta), and right ventricular hypertrophy [1].

The development of multidetector computed tomography has resulted in marked advancements in the diagnosis of congenital heart disease (CHD) which has renewed interest in the classifications and definitions used to describe the anatomy of the heart and great vessels. The sequential, segmental approach to analyzing CHD patient images was introduced nearly three decades ago and is used worldwide [1–5]. Thus, a thorough understanding of both the nomenclature and anatomy applied in this approach is essential to the proper and error-free interpretation of CHD CTA images [6]. The definitions described below are based on the segmental, sequential approach to classifying CHD which is described in Chap. 5.

The first attempt to repair a patient with transposition of the great arteries (TGA) was performed by Senning who successfully constructed an atrial baffle in 1958 [1]. The procedure employed an atrial baffle created from autologous tissue to redirect caval blood to the left atrium which emptied into the left ventricle which then pumped the deoxygenated blood to the lungs. Pulmonary venous blood was redirected to the morphologic right atrium and through the tricuspid valve into the right ventricle which then filled the aorta with oxygenated blood. Subsequently, in 1964, Mustard introduced an atrial switch procedure utilizing prosthetic patch material to create an intra-atrial baffle (Figs. 23.1 and 23.2) [2, 3]. See Fig. 19.22 for a diagram of the uncorrected circulation and the circulation after the atrial switch procedure which normalizes the blood flow circuit.

Ebstein anomaly is a myopathy of the right ventricle that results in variable degrees of failure of delamination of the valve leaflets, leading to tricuspid valve regurgitation and right ventricular dysfunction. The classic pathology is apical (downward) displacement of the tricuspid valve leaflets (most frequently septal followed by posterior and anterior leaflets) with abnormal adherence of the leaflets to the underlying myocardium.

The first surgical repair of aortic coarctation was performed in 1944 [1]. Since then three basic surgical methods have evolved for repair of classic short-segment aortic coarctation (CoAo): resection of the coarcted segment with end-to-end anastomosis (Fig. 32.1), subclavian flap aortoplasty (distal left subclavian artery used to augment aortic lumen at the coarctation site), and prosthetic patch aortoplasty (prosthetic patch inserted to widen the aortic lumen) [2]. The choice of procedure depends on the age of the patient, the type of associated malformations, and the morphology of the coarctation itself. Surgical treatment is preferred in neonates and infants. The other procedure types have been used in adults. Subclavian flap aortoplasty is no longer commonly performed because it requires sacrifice of the left subclavian artery which leads to arm claudication with exercise and diminished growth of the left arm [3].

Vascular CT angiography manual , Vascular CT angiography manual , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

Liquefactive necrosis within a large spheroid zone of mitral annular calcification (LNMAC) is an atypical but increasingly recognized variant of mitral annular calcification (MAC). Proposed MRI, echo, and CT imaging criteria for diagnosis of this unusual disease entity are discussed along with a review of the prognosis, histopathology, and management implications. A comprehensive ECHO, CT, and MRI imaging approach to diagnostic differentiation from other cardiac masses, allowing characterization of the differing components of this unusual lesion is emphasized. Differentiation from surrounding myocardium, and demonstration of peripheral ring type hyperenhancement, or hyperintense signal in the wall of this lesion, seen with specific inversion recovery MRI sequences is presented as a major diagnostic criterion. The relationship of these MRI image findings to underlying pathology is also discussed. An illustrative case vignette is provided for clinical reference.

Multislice computed tomographic coronary angiography (CTCA) provides accurate noninvasive assessment of coronary artery disease (CAD). However, data on the prognostic value of CTCA in patients with suspected CAD are only beginning to emerge. The aim of the study was to assess the prognostic value of CTCA in patients with suspected CAD. Patients (males = 259, females = 235; mean age 58.2 ± 9.8 years) with suspected CAD who underwent 16- or 64-slice CTCA were followed for 1,308 ± 318 days for cardiac death, nonfatal myocaridal infarction (MI) and late (>90 days after CTCA) revascularization. Patient outcomes were related to clinical and CTCA data. Cox proportional-hazards model was applied in stepwise forward fashion to identify outcome predictors. Coronary artery plaque was found in 340 patients. Cardiac events occurred in 40 patients including cardiac death (n = 9), nonfatal MI (n = 8) and late revascularization (n = 23). A multivariable analysis identified the following independent predictors for adverse cardiac events: obstructive plaque in a proximal coronary artery segment (hazard ratio (HR) 2.73; 95% confidence interval (CI): 1.35-5.54; P = 0.005), the number of segments with noncalcified plaque(s) (HR 1.53 per segment; 95%CI: 1.21-1.92; P < 0.001), the number of segments with mixed plaque(s) (HR 1.56 per segment; 95%CI: 1.27-1.92; P < 0.001) and the number of segments with calcified plaque(s) (HR 1.21 per segment; 95%CI: 1.07-1.37; P = 0.002). In patients with suspected CAD, both the extent and composition of atherosclerotic plaque as determined by CTCA are prognostic of subsequent cardiac events.

The thoracic aorta extends from aortic annulus to the diaphragm and includes the ascending aorta, the aortic arch, and the descending thoracic aorta. The first 3 cm of the proximal aorta are intrapericardial. The thoracic aorta anatomy may be seen in Figs. 5.1–5.3.

Vascular computed tomographic (CT) angiography is a less complicated technique than cardiac CT angiography since for the most part the structures of interest are static. The key to vascular CT angiography is to optimize contrast opacification at the point of interest at the time that the region of interest is scanned. To succeed, protocols must allow optimal contrast timing. This requires coordinating the appropriate volume of contrast over the appropriate time at the appropriate rate of injection. While with cardiac CT angiography both the test bolus and bolus tracking techniques are both employed to appropriately time the scan after contrast injection, vascular CT angiography most often employs bolus tracking where a strategic region of interest is selected depending on the scan type and imaging begins when the Hounsfield units (HU) within the selected region of interest reach a predetermined threshold.

The lower extremity peripheral arterial anatomy is represented in Figs. 8.1 and 8.2. The distal aorta bifurcates into the common iliac arteries (CIA). The CIAs bifurcate into the internal iliac artery and the external iliac artery, which then become the common femoral artery (CFA). The CIAs usually course anterior to the iliopsoas muscle but may run posterior to it. This normal variant should be noted.

The abdominal aorta begins at the aortic hiatus of the diaphragm and terminates at the aortic bifurcation to become the iliac arteries. Abdominal aortic branches are divided into three sets: visceral, parietal, and terminal branches. Visceral branches include the celiac artery, the superior mesenteric artery (SMA), the inferior mesenteric artery (IMA), the middle suprarenal arteries, the renal arteries, the internal spermatic arteries, and the ovarian arteries (in females). With the exception of the SMA and IMA, all visceral branches are paired. Parietal branches include the inferior phrenic arteries (paired), the lumbar arteries (paired), and the middle sacral artery. The common iliac arteries make up the terminal branches.

Many of the concepts and sections in this chapter were excerpted from the first book in this series, Cardiac CT Angiography Manual.1 This chapter is rewritten to be more inclusive and up to date.

When beginning proximally, the normal aortic arch gives rise to the right brachiocephalic artery, the left carotid artery, and, finally, the left subclavian artery. The brachiocephalic artery and the left carotid artery are more anterior on the arch. The right common carotid artery and right vertebral arteries arise from the right brachiocephalic artery. The right common carotid artery splits into the right internal and the right external carotid arteries. The left common carotid artery, arising directly from the aortic arch, gives rise to the left internal and the left external carotid artery. The carotid bulb (Fig. 5.4) refers to the region just before the bifurcation of the internal carotid artery. More distally on the arch, the left subclavian artery arises and gives off the left vertebral artery. Many normal variant arch anomalies can occur (Figs. 5.5–5.9).

• A frequent, if not predominant, complaint of persons reporting symptoms of multiple chemical sensitivities (MCS) is that of heightened sensitivity to smells. In this study odor detection thresholds for phenyl ethyl alcohol (a major component of rose oil) and methyl ethyl ketone (a common solvent) were measured in 18 persons exhibiting symptoms of MCS and in 18 matched normal controls. In addition, nasal resistance, blood pressure, heart rate, and respiration rate were determined before and after the olfactory tests. Scores on the Beck Depression Inventory were obtained prior to testing. Although olfactory thresholds were equivalent in the two study groups, the MCS group evidenced significantly higher nasal resistances, respiration rates and Beck Depression Inventory scores. Decreases in systolic blood pressure and pulse were noted in both groups across the test sessions. These results do not support the hypothesis that MCS is associated with greater olfactory threshold sensitivity (at least to the two target chemicals), but do suggest that MCS is associated with depression, increased respiration rate, and decreased nasal airway patency. ( Arch Otolaryngol Head Neck Surg 1988;114:1422-1427)