Bruce A. Urban

Prospectively Gated Transverse Coronary CT Angiography versus Retrospectively Gated Helical Technique: Improved Image Quality and Reduced Radiation Dose

PURPOSE To retrospectively compare image quality, radiation dose, and blood vessel assessability for coronary artery computed tomographic (CT) angiograms obtained with a prospectively gated transverse (PGT) CT technique and a retrospectively gated helical (RGH) CT technique. MATERIALS AND METHODS This HIPAA-compliant study received a waiver for approval from the institutional review board, including one for informed consent. Coronary CT angiograms obtained with 64-detector row CT were retrospectively evaluated in 203 clinical patients. A routine RGH technique was evaluated in 82 consecutive patients (44 males, 38 females; mean age, 55.6 years). The PGT technique was then evaluated in 121 additional patients (71 males, 50 females; mean age, 56.7 years). All images were evaluated for image quality, estimated radiation dose, and coronary artery segment assessability. Differences in image quality score were evaluated by using a proportional odds logistic regression model, with main effects for three readers, two techniques, and four arteries. RESULTS The mean effective dose for the group with the PGT technique was 2.8 mSv; this represents an 83% reduction as compared with that for the group with the RGH technique (mean, 18.4 mSv; P < .001). The image quality score for each of the arteries, as well as the overall combined score, was significantly greater for images obtained with PGT technique than for images obtained with RGH technique. The combined mean image quality score was 4.791 for images obtained with PGT technique versus 4.514 for images obtained with RGH technique (proportional odds model odds ratio, 2.8; 95% confidence interval: 1.7, 4.8). The percentage of assessable coronary artery segments was 98.6% (1196 of 1213) for images obtained with PGT technique versus 97.9% (1741 of 1778) for images obtained with RGH technique (P = .83). CONCLUSION PGT coronary CT angiography offers improved image quality and substantially reduced effective radiation dose compared with traditional RGH coronary CT angiography.

Multidetector CT angiography in the evaluation of pancreatic carcinoma: preliminary observations.

Multidetector CT (MDCT) provides unparalleled capabilities for combining narrow scan collimation with rapid data acquisition protocols. When combined with CT angiographic techniques and 3D-volume rendering we are able to create unique displays for evaluating a range of clinical pathologies. In this pictorial review we present the potential advantages of using MDCT angiography for the evaluation of pancreatic cancer and its role in the accurate staging of these patients. The use of dual-phase CT scanning in both the arterial phase and portal phase is addressed with the role of 3D CT angiography clearly defined. Numerous case studies are presented to show the advantages of these techniques over simple axial CT imaging.

CT findings in cystic schwannoma of the pancreas.

Cystic neoplasms of the pancreas are relatively rare, accounting for ∼1% of all pancreatic malignancies and 10-15% of all pancreatic cysts (1,2). We present a case of a cyctic schwannoma of the pancreas, detected by CT

Targeted helical CT of the acute abdomen: Appendicitis, diverticulitis, and small bowel obstruction

CT, especially helical CT, provides a fast and reliable modality for evaluation of the patient presenting with acute abdominal pain. Helical CT can provide an accurate diagnosis in the majority of patients and has found great utility in the evaluation of acute gastrointestinal emergencies, including acute appendicitis, diverticulitis, and small bowel obstruction. This article reviews proper helical CT technique, diagnostic imaging findings, and pitfalls of interpretation in evaluation of these acute abdominal disorders.

Spiral CT following the Whipple procedure: distinguishing normal postoperative findings from complications.

Following a Whipple procedure for a patient with pancreatic cancer, postoperative imaging with CT is essential to exclude complications and to identify recurrence. Accurate interpretation of these examinations requires knowledge of the type of surgery performed and the normal appearance of the abdomen on CT following this complex surgery. The purpose of this pictorial essay is to illustrate the normal appearance of the bowel following a Whipple procedure as well as some of the complications.

The value of computed tomography scanning for the detection of coronary artery disease in patients with idiopathic pulmonary fibrosis

Background and objective:  Patients with idiopathic pulmonary fibrosis (IPF) have a higher prevalence of coronary artery disease and this could have an impact on their outcomes. We investigated the predictive ability of coronary artery calcification, assessed by routine CT, which may predict the presence of coronary artery disease.

IMAGING OF THORACIC AORTIC DISEASE

Computed tomography, magnetic resonance imaging, and transesophageal echocardiography represent the relatively noninvasive techniques available for imaging thoracic aortic disease, especially in the evaluation of aneurysms and dissections. The article discusses the technique and application of these modalities in the evaluation of thoracic aorta. Imaging appearances of the commonly encountered pathologies of the thoracic aorta are presented and discussed, and potential pitfalls of technique and diagnosis are addressed.

Spiral CT of musculoskeletal pathology: preliminary observations.

Spiral or helical computed tomography (CT) allows the rapid acquisition of volumes of CT data in a 24- to 32-s time frame. Rapid data acquisition is accompanied by the ability to reconstruct the images at any pre-determined interval (1–10 mm). This technique is optimal for studies requiring iodinated vascular contrast because it allows data acquisition during the peak contrast levels, optimizing lesion detection. The technique is also excellent for studies that need two and /or three-dimensional reconstruction as it decreases the chance of interscan motion. Spiral CT has significant potential for a wide range of musculoskeletal imaging applications including in musculoskeletal infection, soft tissue tumors, trauma, and in the oncologic patient.

Spiral CT of the liver: Current applications

Spiral CT allows rapid imaging of the liver resulting in improved contrast dynamics compared with conventional CT techniques. Improved lesion detection has been shown with spiral CT by using overlapping reconstruction intervals and by eliminating respiratory misregistration. Vascular and parenchymal abnormalities, including portal venous thrombosis or cirrhosis with development of collateral vessels, are readily appreciated using spiral technique. Combining spiral CT and portography enhances lesion detection by maintaining high levels of hepatic contrast enhancement for the duration of the liver scan.

Three-dimensional volume-rendering CT angiography in vasculitis: spectrum of disease and clinical utility.

Spiral computed tomographic angiography (CTA) coupled with three-dimensional volume-rendering image processing is a less invasive alternative to conventional catheter angiography. The technique has been used successfully in a variety of vascular diseases. In this pictorial essay, we review the CTA findings in selected cases of vasculitis. Technical considerations and the potential clinical value of this method are discussed.