Carlos A. Rojas

Evaluation of the Pediatric Craniocervical Junction on MDCT

OBJECTIVE The purpose of our study was to establish normal values on MDCT images for the measurement of various craniocervical junction relationships in children and to address discrepancies in the literature based on radiographic values. MATERIALS AND METHODS Accepted methods of evaluating the craniocervical junction were used to calculate normal values in 117 normal children on MDCT images with multiplanar reconstructions. The basion-axial interval, basion-dens interval, Powers ratio, atlantodental interval, and atlantooccipital interval were measured in each patient and compared with accepted data based on radiographs. RESULTS The basion-axial interval was difficult to reproduce on MDCT images. In 97.5% of patients, the basion-dens interval was less than 10.5 mm compared with 12 mm based on data from radiographs. Separating the patient population into those in whom the os terminale was ossified and those in whom it was not revealed a difference of 2 mm in the upper limit of normal (9.5 and 11.6 mm, respectively). The Powers ratio showed no significant difference compared with data obtained using radiographs. In 97.5% of the population, the atlantodental interval was less than 2.6 mm, compared with 4-5 mm measured on radiographs. The atlantooccipital interval showed 97.5% of the population falling below 2.5 mm at any point in the joint space, compared with the previously accepted value of 5 mm. CONCLUSION Normal values for the craniocervical junction articulations and relationships as seen on MDCT are different from the accepted ranges of normal based on radiographs. The values should be considered the normal values in the pediatric population on MDCT.

Prospectively Ecg-triggered High-pitch Spiral Acquisition for Cardiac Ct Angiography in Routine Clinical Practice: Initial Results

Purpose: This study was conducted to evaluate the mode of application, image quality (IQ), and radiation exposure resulting from introduction of a prospectively electrocardiogram-triggered high-pitch cardiac computed tomography angiography (CTA) acquisition mode into routine clinical practice. Materials and Methods: A total of 42 prospectively triggered cardiac CTAs were conducted on 34 patients (11 female, 23 male; mean age 56±15 y) using a high-pitch mode (pitch 3.4) on a dual-source CT. In 8 of these patients with higher heart rates or occasional premature ventricular contractions, 2 immediately subsequent CTAs were performed (“double flash protocol”). Subjective IQ was assessed for coronary arteries using a 4-point scale (1=unevaluable to 4=excellent). Contrast-to-noise ratio (CNR) was measured in 9 locations. CT Dose Index and dose-length product were obtained, and the patients’ effective dose was calculated. Results: Mean effective doses were 2.6±1.4 mSv (range: 1.1 to 6.4) for the entire cardiac examination and 1.4±0.7 mSv (0.4 to 3.1) for individual high-pitch cardiac CTA. z-coverage ranged from 9.9 cm in a native coronary CTA to 31.4 cm in a bypass graft case. The overall subjective IQ was good to excellent (mean score: 3.5), with 1.5% unevaluable coronary segments. The “double flash protocol” resulted in a fully diagnostic CT study in all cases just after taking both scans into consideration. The mean CNR of all locations was 19.7±2.6. Conclusion: Prospectively electrocardiograph-triggered high-pitch-mode cardiac CTA is a feasible and promising technique in clinical routine, allowing for evaluation of coronaries at good-to-excellent IQ and providing high CNR and minimal radiation doses. The “double flash protocol” might become a more robust tool in patients with elevated heart rates or premature ventricular contractions.

Aspiration-related lung diseases.

Aspiration is a common but underrecognized clinicopathologic entity, with varied radiographic manifestations. Aspiration represents a spectrum of diseases, including diffuse aspiration bronchiolitis, aspiration pneumonitis, airway obstruction by foreign body, exogenous lipoid pneumonia, interstitial fibrosis, and aspiration pneumonia with or without lung abscess formation. Many patients who aspirate do not present with disease, suggesting that pathophysiology is related to a variety of factors, including decreased levels of consciousness, dysphagia, impaired mucociliary clearance, composition of aspirate, and impaired host defenses. In this pictorial essay, we will review the different types of aspiration lung diseases, focusing on their imaging features and differential diagnosis.

Cardiovascular complications of cocaine: Imaging findings

Cocaine is the second most commonly abused illicit drug in the US and the most common one involved in emergency department visits, the majority of which are related to the cardiovascular system. Cardiovascular complications related with cocaine abuse include myocardial ischemia and infarction, myocarditis, hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic dissection, thrombosis, stroke and cerebral hemorrhage, and different forms of visceral ischemia, among others. In an era where cocaine use has reached epidemic proportions, it is necessary for the radiologist to understand the pathophysiology, clinical presentation, and imaging characteristics of its cardiovascular complications.

Pertinent reportable incidental cardiac findings on chest CT without electrocardiography gating: review of 268 consecutive cases.

Background Pertinent reportable cardiac findings on non-electrocardiography (ECG)-gated chest CT examinations have become easier to detect given recent advancements in multidetector CT technology. However, those findings are easily overlooked on routine chest CT without ECG gating given residual inherent cardiac motion artifact and non-cardiac indications. Purpose To describe and quantify the types of pertinent reportable cardiac findings that can be detected on chest CT examinations without ECG gating and evaluate how often they were reported. Material and Methods Two radiologists retrospectively reviewed (blinded to the original interpretation) 268 consecutive routine adult chest CT examinations without ECG gating for the presence of pertinent reportable cardiac findings. Retrospective interpretations were then compared with the original radiological reports. Results One hundred and sixty-three patients (61%) had pertinent reportable cardiac findings. The findings encountered included: coronary artery disease (n = 131; 80.0%), coronary artery bypass grafts (n = 10; 6.1%), left ventricular aneurysm (n = 1; 0.6%), valve calcification (n = 131; 80.0%), valve repair/replacement (n = 5; 3.1%), pericardial effusion (n = 33; 20.2%), left atrial appendage thrombus (n = 1; 0.6%), cardiac mass (n = 1; 0.6%), and cardiac chamber enlargement (n = 29; 17.8%). On the original radiological reports 22.3% of the pertinent reportable cardiac findings, detected by the two radiologists retrospectively, were not reported. Conclusion Detection of pertinent reportable cardiac findings on routine chest CT examinations without ECG gating is possible. The high volume of chest CT examinations without ECG gating represents an opportunity for radiologists to comment on the presence or absence of cardiac disease which may influence future clinical decisions.

The new era of radiology teaching files.

OBJECTIVE In this article, we describe how we constructed a radiology teaching file that simulates real-life scenarios and discuss some of the advantages it affords. CONCLUSION Using OsiriX imaging software and iWork Pages, we have created a HIPAA-compliant interstitial lung disease radiology teaching resource that allows the user to navigate through the complete dataset of images for each patient. Integrated within the file is a navigation tool that allows the user to access the patients clinical report, imaging reports, pulmonary function tests, and pathology report simultaneously. To our knowledge, this is the first teaching file of its kind.

Imaging of atrial septal defects: echocardiography and CT correlation

Adult patients with atrial septal defects (ASDs) have variable clinical presentations that can range from dyspnoea on exertion to cerebral vascular accidents from paradoxical embolism. Currently echocardiography is the mainstay in the diagnosis and follow-up of patients with ASDs. As CT technology advances and low radiation techniques improve, cardiac CT is becoming a desirable method to evaluate patients with ASDs when echocardiographic evaluation is limited. Correct diagnosis and appropriate management of patients with patent foramen ovales (PFOs) and ASDs relies on an understanding of the embryologic development patterns that resulted in the malformation and associated anomalies. In this review, we illustrate the development of the interatrial septum and the foramen ovale. We discuss the diagnosis of PFOs and ASDs by echocardiography and highlight the incremental benefit of CT to further elucidate defect morphology, associated anomalies, and anatomy post-repair. The primary atrium starts as a common cavity.1 Starting at 5 weeks of gestation, the primordial single atrium begins dividing into right and left sides by formation and fusion of two septa: the septum primum and septum secundum (figure 1). Early in the fifth week of gestation the septum primum begins to form near the centre of the roof of the common atrium, growing downward to the endocardial cushions, and partially dividing the common atrium into right and left counterparts (figure 1, A-1 and A-2). The gap between the septum primum and endocardial cushions is known as the ostium primum. Before the septum primum and endocardial cushions fuse, perforations develop within the cephalic portion of the septum primum through apoptosis, creating a large window known as the ostium secundum. At the end of the sixth week the caudal free edge of the septum primum reaches the atrioventricular cushions and fuses with them, closing the ostium primum (figure 1, B-1 and …

CT Angiography of the Thoracic Aorta

Patients with thoracic aortic diseases may be completely asymptomatic (as in thoracic aortic aneurysms) or present acutely with severe chest pain (as in acute aortic dissections). Thoracic aortic disease is often occult until a life-threatening complication occurs or the disease is discovered incidentally on imaging. Multidetector-row computed tomography (MDCT) can be used to diagnose various acute and chronic abnormalities of the aorta, including aortic aneurysms, aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, traumatic aortic transection, and congenital malformations. This article reviews the MDCT appearance of various thoracic aortic diseases.

Embryology and Developmental Defects of the Interatrial Septum

OBJECTIVE The various types of atrial septal defects (ASDs) can be differentiated on the basis of their imaging appearance on MDCT. CONCLUSION It is fundamental for the cardiac imager to understand the embryologic development of the interatrial septum and the morphogenic differences of ASDs.

Adult congenital heart disease imaging with second-generation dual-source computed tomography: initial experiences and findings.

Adult congenital heart disease patients present a unique challenge to the cardiac imager. Patients may present with both acute and chronic manifestations of their complex congenital heart disease and also require surveillance for sequelae of their medical and surgical interventions. Multimodality imaging is often required to clarify their anatomy and physiology. Radiation dose is of particular concern in these patients with lifelong imaging needs for their chronic disease. The second-generation dual-source scanner is a recently available advanced clinical cardiac computed tomography (CT) scanner. It offers a combination of the high-spatial resolution of modern CT, the high-temporal resolution of dual-source technology, and the wide z-axis coverage of modern cone-beam geometry CT scanners. These advances in technology allow novel protocols that markedly reduce scan time, significantly reduce radiation exposure, and expand the physiologic imaging capabilities of cardiac CT. We present a case series of complicated adult congenital heart disease patients imaged by the second-generation dual-source CT scanner with extremely low-radiation doses and excellent image quality.