Charles S. White

Coronary CT angiography in emergency department patients with acute chest pain: triple rule-out protocol versus dedicated coronary CT angiography

Immediate coronary catheterization is mandatory for high risk patients with typical chest pain in the emergency department (ED). In contrast, in ED patients with acute chest pain but low to intermediate risk, traditional management protocol includes serial ECG, cardiac troponins and radionuclide perfusion imaging. However, this protocol is time-consuming and expensive, and definite treatment of unstable angina is often delayed. Due to advances of multi-detector CT (MDCT) technology, dedicated coronary CT angiography provides the potential to rapidly and reliably diagnose or exclude acute coronary syndrome in ED patients with acute chest pain. Moreover, major life-threatening causes of ED chest pain (i.e., acute aortic syndrome and pulmonary embolism as well as acute coronary syndrome) can simultaneously be assessed by the so-called “triple rule-out” protocol with a single scan. In ED patients with atypical chest pain and low to intermediate risk, the triple rule-out protocol may be preferred, especially in older patients who have relatively lower risk of lifelong radiation-induced cancer. However, the increased radiation dose resulting from the extended volume coverage with this protocol should be fully considered prior to performing this protocol. Therefore, in ED patients who have a low clinical suspicion of pulmonary embolism and acute aortic syndrome, especially younger patients, dedicated coronary CT angiography accompanied by modifications to reduce radiation dose is recommended.

Lung nodule CAD software as a second reader: a multicenter study.

RATIONALE AND OBJECTIVESnThe purpose of this multicenter, multireader study was to evaluate the performance of computed tomography (CT) lung nodule computer-aided detection (CAD) software as a second reader.nnnMETHODS AND MATERIALSnThe study involved 109 patients from four sites. The data were collected from a variety of multidetector CT scanners and had different scan parameters. Each chest CT scan was divided into four quadrants. A group of three expert thoracic radiologists identified nodules between 4 and 30 mm in maximum diameter within each quadrant. The standard of reference was established by a consensus read of these experienced radiologists. The cases were then interpreted by 10 other radiologist readers with varying degrees of experience, without and then with CAD software. These readers identified nodules and assigned an actionability rating to each quadrant before and after using CAD software. Receiver operating characteristic curves were used to measure the performance of the readers without and with CAD software.nnnRESULTSnThe average increase in area under the curve for the 10 readers with CAD software was 1.9% for a 95% confidence interval (0.8-8.0%). The area under the curve without CAD software was 86.7% and with CAD software was 88.7%. A nonsignificant correlation was observed between the improvement in sensitivity and experience of the radiologists. The readers also showed a greater improvement in patients with cancer as compared to those without cancer.nnnCONCLUSIONSnIn this multicenter trial, CAD software was shown to be effective as a second reader by improving the sensitivity of the radiologists in detecting pulmonary nodules.

Use of a computer-aided detection system to detect missed lung cancer at chest radiography.

PURPOSEnTo study the ability of a computer-aided detection (CAD) system to detect lung cancer overlooked at initial interpretation by the radiologist.nnnMATERIALS AND METHODSnInstitutional review board approval was given for this study. Patient consent was not required; a HIPAA waiver was granted because of the retrospective nature of the data collection. In patients with lung cancer diagnosed from 1995 to 2006 at two institutions, each chest radiograph obtained prior to tumor discovery was evaluated by two radiologists for an overlooked lesion. The size and location of the nodules were documented and graded for subtlety (grades 1-4, 1 = very subtle). Each radiograph with a missed lesion was analyzed by a commercial CAD system, as was the follow-up image at diagnosis. An age- and sex-matched control group was used to assess CAD false-positive rates.nnnRESULTSnMissed lung cancer was found in 89 patients (age range, 51-86 years; mean age, 65 years; 80 men, nine women) on 114 radiographs. Lesion size ranged from 0.4 to 5.5 cm (mean, 1.8 cm). Lesions were most commonly peripheral (n = 63, 71%) and in upper lobes (n = 67, 75%). Lesion subtlety score was 1, 2, 3, or 4 on 43, 49, 17, and five radiographs, respectively. CAD identified 53 (47%) and 46 (52%) undetected lesions on a per-image and per-patient basis, respectively. The average size of lesions detected with CAD was 1.73 cm compared with 1.85 cm for lesions that were undetected (P = .47). A significant difference (P = .017) was found in the average subtlety score between detected lesions (score, 2.06) and undetected lesions (score, 1.68). An average of 3.9 false-positive results occurred per radiograph; an average of 2.4 false-positive results occurred per radiograph for the control group.nnnCONCLUSIONnCAD has the potential to detect approximately half of the lesions overlooked by human readers at chest radiography.

Use of multidetector computed tomography for the assessment of acute chest pain : a consensus statement of the North American Society of Cardiac Imaging and the European Society of Cardiac Radiology

The diagnosis of patients with acute chest pain remains a challenging problem. There are approximately 6 million chest pain related emergency department (ED) visits annually in the US alone [1]. Approximately 5.3% of all ED patients are seen because of chest pain and reported admission rates are between 30% and 72% for these patients [2]. Only 15–25% of patients presenting with acute chest pain are ultimately diagnosed as having an acute coronary syndrome (ACS). Of those patients who were admitted to the chest pain unit, 44% ultimately had

Management of Small (3–5-mm) Pulmonary Nodules at Chest CT: Global Survey of Thoracic Radiologists

PURPOSEnTo prospectively determine management strategies used by international thoracic radiologists in evaluation of small (3-5-mm) pulmonary nodules at chest computed tomography (CT).nnnMATERIALS AND METHODSnInstitutional review board exemption was granted for this study, which included consenting participants. An electronic survey was sent to members of major thoracic radiology societies in North America, Europe, and Asia. The main part of the survey consisted of four management questions with clinical scenarios. Associations between recommendations and years of experience, location in a region endemic for granulomatous disease, country, and practice type were assessed. Univariate analysis was performed to determine differences in follow-up recommendations on the basis of patient characteristics, percentage of chest CT scans obtained at follow-up, years of experience in radiology, and professional society affiliation of respondents. Differences in categorical variables were examined by using Pearson chi(2) and Fisher exact tests.nnnRESULTSnTwo hundred two (25%) of approximately 800 online surveys were completed. Surveys from respondents from the United States comprised 61% of completed surveys. Median experience of respondents was 11-20 years. Fifty-two percent practice in an area endemic for granulomatous disease. Only 35% of practices have a policy in place for nodule management. In scenarios in which patients had a low likelihood of malignancy, respondents preferential recommendation was short-term CT follow-up (3-6 months) rather than intermediate-term CT follow-up (12 months) for patients older than 40 years compared with their recommendation in patients younger than 40 years, in whom recommendations for short- or intermediate-term follow-up were roughly equal. In scenarios in which patients had a high risk of malignancy, follow-up was also strongly favored instead of biopsy, with short-term follow-up more commonly advocated. Location in an area endemic for granulomatous disease and years of experience also influenced recommendations.nnnCONCLUSIONnGlobally, the most common recommendation for CT evaluation of nodules is short-term follow-up, with a tendency toward less aggressiveness in scenarios in which patients had lower risk of malignancy and increased aggressiveness in scenarios in which patients had higher risk of malignancy.

ACR Appropriateness Criteria® on Chest Pain, Suggestive of Acute Coronary Syndrome

Acute chest pain suggestive of acute coronary syndrome is a frequent complaint in the emergency department. Acute coronary syndromes include myocardial infarction and unstable angina. Being able to establish the diagnosis rapidly and accurately may be lifesaving. A cardiac workup is indicated in this subset of patients in the acute setting, even if there are no ischemic changes on electrocardiography. If the clinical examination and initial cardiac workup suggest that a patient is having myocardial ischemia, the patient will usually be urgently referred for invasive coronary angiography and revascularization. In stable patients without evidence of ST elevation and ongoing myocardial ischemia, an initially conservative approach is sometimes considered. Cardiac risk stratification of this subgroup of patients who are at low and intermediate risk for coronary artery disease is recommended before discharge, and imaging is necessary to exclude ischemia as an etiology. Noninvasive cardiac imaging modalities include chest radiography, single photon-emission CT myocardial perfusion imaging, echocardiography, multidetector CT, PET, and MRI. Noncardiac etiologies of chest pain include aortic dissection, aortic aneurysm, pulmonary embolism, pericardial disease, and lung parenchymal disease. Noninvasive cardiac imaging in patients who are at low and intermediate risk for coronary artery disease may improve confidence regarding the safety of discharge from the emergency department. In addition to risk stratification, noncoronary etiologies for chest pain can be established with imaging.

MR Imaging of Thoracic Veins

The thoracic venous system can be visualized and characterized well with MR imaging. In this article, MR sequences that are suited for this purpose (including the more advanced techniques) are reviewed. The normal thoracic venous anatomy and a brief summary of its embryogenesis is provided. The appearances of congenital and acquired abnormalities of the systemic and pulmonary thoracic veins are described. This article also discusses recent applications of MR imaging in the evaluation of the pulmonary veins and the left atrium in patients who have atrial fibrillation.

CT appearance of the normal and abnormal breast with mammographic correlation

Mammography is the preferred technique to evaluate the breast but computed tomography (CT) performed for extramammary disease often images breast tissue. We reviewed studies of patients who underwent both CT and mammography to identify abnormalities that were visible with both techniques. The CT appearance of the normal breast, breast cancer, and several other abnormalities is demonstrated in this study. CT may occasionally allow for a precise diagnosis of a previously unsuspected breast lesion but a mammogram is usually required.

Radiation Redux for Coronary CT Angiography: How Low Can We Go?

647 construction is computationally intensive and thus for many years was not suitable for CT because of the inability to reconstruct images based on the large amount of CT projection data in a timely fashion. With advancements in computing power, iterative reconstruction techniques can now be applied to CT and, in fact, a blend of both iterative reconstruction and FBP may be used. This issue of the American Journal of Roentgenology features two articles by Leipsic et al. [2, 3] on the use of iterative reconstruction for coronary CTA, a technique with substantial implications for radiation dose reduction. The first article explores different blends of FBP and iterative reconstruction. With adaptive statistical iterative reconstruction (ASIR, GE Healthcare), the vendor implementation of iterative reconstruction used in the authors’ study, it has been recognized that CT images reconstructed with 100% ASIR, which allows the largest reduction of noise and radiation, can manifest a “plastic” quality that is displeasing to interpreters. The authors found that the best image quality scores were obtained using 40% or 60% ASIR. In the second article, they assessed 574 patients from three institutions, of whom 331 underwent scanning with FBP reconstruction and the remainder with ASIR using similar gating, kVp, and scan length. There was a 27% reduction in radiation dose without an adverse effect on signal, noise, and signal-to-noise ratio. There are some limitations to the study, including the use of only a single interpreter and the lack of blinding to the type of protocol. These studies signal an important advance in managing radiation dose for patients undergoing coronary CTA. A major advantage of iterative reconstruction is that it is supplemental to other radiation reduction techniques, and thus it is not necessary to compromise on the choice of protocol. Moreover, in patients with borderline image quality due to noise for Radiation Redux for Coronary CT Angiography: How Low Can We Go?

CT of Uhl's anomaly in an adult

Uhl’s anomaly is an extremely rare condition of unknown cause characterized by complete or partial absence of the right ventricular myocardial layer, which is replaced by nonfunctional fibroelastic tissue. The disease causes progressive right-sided heart failure, increased right-sided cardiac pressure, massive peripheral edema, and ascites. Patients usually present in infancy and rarely survive to adulthood. The disease appears to be congenital in origin. Diagnosis was previously made at autopsy, but advances in imaging now permit diagnosis by echocardiography or cross-sectional imaging (computed tomography or magnetic resonance). We present a case of a 51-year-old patient with Uhl’s anomaly who underwent placement of a ventricular assist device as a bridge to cardiac transplantation, and discuss CT findings.