Hansel J. Otero

Iodinated Contrast Opacification Gradients in Normal Coronary Arteries Imaged with Prospectively ECG-Gated Single Heart Beat 320-Detector Row Computed Tomography

Background—To define and evaluate coronary contrast opacification gradients using prospectively ECG-gated single heart beat 320-detector row coronary angiography (CTA). Methods and Results—Thirty-six patients with normal coronary arteries determined by 320×0.5-mm detector row coronary CTA were retrospectively evaluated with customized image postprocessing software to measure Hounsfield Units at 1-mm intervals orthogonal to the artery center line. Linear regression determined correlation between mean Hounsfield Units and distance from the coronary ostium (regression slope defined as the distance gradient Gd), lumen cross-sectional area (Ga), and lumen short-axis diameter (Gs). For each gradient, differences between the 3 coronary arteries were analyzed with ANOVA. Linear regression determined correlations between measured gradients, heart rate, body mass index, and cardiac phase. To determine feasibility in lesions, all 3 gradients were evaluated in 22 consecutive patients with left anterior descending artery lesions ≥50% stenosis. For all 3 coronary arteries in all patients, the gradients Ga and Gs were significantly different from zero (P<0.0001), highly linear (Pearson r values, 0.77 to 0.84), and had no significant difference between the left anterior descending, left circumflex, and right coronary arteries (P>0.503). The distance gradient Gd demonstrated nonlinearities in a small number of vessels and was significantly smaller in the right coronary artery when compared with the left coronary system (P<0.001). Gradient variations between cardiac phases, heart rates, body mass index, and readers were low. Gradients in patients with lesions were significantly different (P<0.021) than in patients considered normal by CTA. Conclusions—Measurement of contrast opacification gradients from temporally uniform coronary CTA demonstrates feasibility and reproducibility in patients with normal coronary arteries. For all patients, the gradients defined with respect to the coronary lumen cross-sectional area and short-axis diameters are highly linear, not significantly influenced by the coronary artery (left anterior descending artery versus left circumflex versus right coronary artery), and have only small variation with respect to patient parameters. Preliminary evaluation of gradients across coronary artery lesions is promising but requires additional study.

The “Post-64” Era of Coronary CT Angiography: Understanding New Technology from Physical Principles

Multidetector CT now provides noninvasive coronary imaging, and patients with a low or intermediate probability of coronary artery disease can be imaged with radiation levels comparable to catheterization. Cardiac imaging drives rapid progress in CT hardware. To best apply evolving technology, imagers and referring clinicians need a solid understanding of spatial resolution, temporal resolution, volume coverage, and radiation dose. This article defines and discusses interactions between these parameters for state-of-the-art CT.

Twenty years of cost-effectiveness analysis in medical imaging: are we improving?

PURPOSE To determine the growth rate, methodologic clarity, and quality changes in cost-effectiveness analyses (CEAs) and to assess whether the U.S. Panel on Cost-effectiveness in Health and Medicine recommendations affected CEA studies in which imaging technologies were evaluated. MATERIALS AND METHODS Six databases were systematically searched for CEA reports published between 1985 and 2005. All imaging-related studies were selected and grouped according to year, country, and journal of publication, as well as imaging modality and disease being studied. Two readers with formal training in decision analysis and CEA used a seven-point (1, low; 7, high) Likert scale based on reasonableness of assumptions, quality of presentation, and adherence to guidelines to independently evaluate study quality. Quality scores according to year, country, and journal of publication were compared with the unpaired Student t test. RESULTS The first radiology-related CEA was published in 1985; 111 radiology-related CEAs were published between 1985 and 2005. The average number of studies increased from 1.6 per year between 1985 and 1995 to 9.4 per year between 1996 and 2005. Eighty-six studies were performed to evaluate diagnostic imaging technologies, and 25 were performed to evaluate interventional imaging technologies. Ultrasonography (35.0%), angiography (31.5%), magnetic resonance imaging (22.5%), and computed tomography (19.8%) were evaluated most frequently. Forty-nine studies received government funds; 42 did not disclose the source of funding. The mean quality score was 4.23 +/- 1.12 (standard deviation), without significant improvement over time. Scores in studies performed in the United States were significantly higher than scores in studies that were not performed in the United States (4.45 +/- 1.02 vs 3.61 +/- 1.17, respectively; P < .01). Scores were also higher in journals with three or more CEA articles published during the study period than in journals with two or fewer CEA articles published during this period (4.54 +/- 1.09 vs 3.91 +/- 1.06, respectively; P < .01). CONCLUSION CEAs are an important tool with which to analyze the value of diagnostic imaging. However, improvement in the quality of analyses is needed. SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/249/3/917/DC1.

Imaging presentation of venous thrombosis in patients with cancer.

OBJECTIVE The purpose of this article is to review the imaging of venous thrombosis in patients with cancer. CONCLUSION Multiple imaging techniques have the capacity to display thrombosis accurately. The optimal choice is dictated by the location and duration of symptoms and by the availability of imaging techniques. Peripheral and superficial thrombi are best managed with ultrasound, whereas central thrombi require CT or MRI. If CT and MRI are contraindicated, flow studies are appropriate. FDG PET/CT appropriately shows venous thrombosis and might play a prominent role in the future.

2015 RAD-AID Conference on International Radiology for Developing Countries: The Evolving Global Radiology Landscape

Abstract Radiology in low- and middle-income (developing) countries continues to make progress. Research and international outreach projects presented at the 2015 annual RAD-AID conference emphasize important global themes, including (1) recent slowing of emerging market growth that threatens to constrain the advance of radiology, (2) increasing global noncommunicable diseases (such as cancer and cardiovascular disease) needing radiology for detection and management, (3) strategic prioritization for pediatric radiology in global public health initiatives, (4) continuous expansion of global health curricula at radiology residencies and the RAD-AID Chapter Network’s participating institutions, and (5) technologic innovation for recently accelerated implementation of PACS in low-resource countries.

Evaluation of low-density neutral oral contrast material in PET/CT for tumor imaging: results of a randomized clinical trial.

OBJECTIVE The objective of this study was to determine the impact on image quality and risks in terms of artifacts and side effects of a low-density barium-based suspension as oral contrast material for CT during PET/CT examinations of an oncologic patient population. SUBJECTS AND METHODS Eighty-five patients (51 men and 34 women; mean age, 53 years; age range, 21-87 years) were prospectively randomized to receive either 0.1% barium sulfate oral suspension or no oral contrast material during PET/CT. Patients in the oral contrast group were given 1,350 mL over 60-75 minutes. The (18)F-FDG PET component of each examination was reviewed for the presence of artifacts by two nuclear medicine physicians and was classified as adequate (no presence of artifactual focal FDG uptake attributed to attenuation-correction errors) or inadequate (focal uptake in attenuation-correction PET images with no corresponding uptake in non-attenuation-corrected PET images). Two radiologists reviewed the CT studies and scored the degree of bowel opacification using a 5-point scale, ranging from 0 for no opacification (i.e., not possible to delineate the bowel structures from the surrounding tissues) to 4 for excellent opacification (i.e., bowel structure identifiable and bowel wall clearly visible). The attenuation values (in Hounsfield units) were recorded in the stomach, duodenum, mid jejunum, and terminal ileum for quantitative analysis. Interobserver variability was assessed using kappa coefficients. RESULTS None of the patients who received oral contrast material experienced side effects. All 85 PET examinations were considered adequate with no observable artifacts. The mean bowel opacification scores of the oral contrast group (2.59 and 2.93) as evaluated by radiologists 1 and 2, respectively, were significantly higher (p < 0.01) than those of the control group (1.55 and 1.59). The level of attenuation achieved in the contrast group was significantly higher than in the control group. The interobserver variability was moderate (kappa = 0.32). CONCLUSION The use of low-density neutral oral contrast material for CT during combined FDG PET/CT studies significantly improves visualization of the bowel structures compared with no contrast material without causing side effects or clinically detectable errors in the attenuation correction of the FDG PET study.

Reimbursement for chest-pain CT: estimates based on current imaging strategies

The purpose of this study was to estimate reimbursement for chest pain CT, assuming no cost increase for current emergent chest pain imaging. Using reported imaging test characteristics, prevalence and risk of coronary heart disease, and Medicare reimbursement schedules, 10,000 simulated patients were evaluated with three chest pain imaging algorithms. The main difference among the algorithms was the initial imaging tool: stress echocardiography, single photon emission computed tomography (SPECT) and chest pain CT. Outcome analysis included deaths, intra- and extra-hospital myocardial infraction, number of tests performed, time utilization, and the cost per patient. The chest pain CT algorithm was assessed with its reimbursement as an unknown to determine a maximum reimbursement that would not increase overall healthcare costs. Stress echocardiography costs

Semi-automatic assessment of pediatric hydronephrosis severity in 3D ultrasound

856.5 per patient with 8.4 observation hours and 646 (27%) negative catheterizations. When SPECT replaces stress echocardiography, the cost increases to

Primary and Metastatic Vascular Neoplasms: Imaging Findings

1,413.7 with average observation of 9.05 hours and 1,060 (36%) negative catheterizations. Chest pain CT minimizes observation (by 8.4 and 9.1 compared to echocardiography and SPECT, respectively); negative catheterizations drop to 266 (12%). Solving for chest pain CT reimbursement as an unkown yields

Venous thrombosis in an outpatient oncologic center: distribution, type, and comorbidities.

433.1 and