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There are few computer-aided detection (CAD) systems that are available for the detection of nodules on chest radiographs. We evaluated the performance of a Food and Drug Administration-approved system and 3 of its subsequent versions to determine their potential to improve readers' accuracy.We tested the performance of 4 generations of CAD software programs, RapidScreen 1.1 and OnGuard 3.0, 4.0, and 5.0 (Riverain Medical), for their ability to detect lung cancer on a sample of 100 patients with and 100 patients without nodules. Each proven nodule (computed tomography scan and/or pathology) was evaluated for its overall difficulty, size, density, shape, contour, and location. The sensitivity and number of false-positive (FP) marks were compared between the different versions; reasons for FP and false-negative marks were analyzed and compared.The newer versions have significantly improved overall sensitivity [62.5% (OnGuard 3.0), 62.5% (4.0), and 64.4% (5.0)] compared with the first version (44.2%). OnGuard 5.0 demonstrated sensitivity of 73.3% for moderately subtle lesions compared with very subtle lesions (20.0%). There was a significant reduction in the average number of FPs per image for each version (3.9 for 1.1, 3.3 for 3.0, 2.6 for 4.0, and 2.0 for 5.0). Rib and vessel crossings were the most common reasons for FPs.The latest version of CAD demonstrates good detection of moderately subtle lesions with a relatively low FP rate.

Objective Cardiac resynchronization therapy (CRT) is an important therapeutic strategy in heart failure. However, there is a high incidence of lead implantation failure and suboptimal response, particularly in ischemic cardiomyopathy. This failure rate may partly be secondary to lack of suitable coronary sinus branches for lead implantation. We sought to assess the presence of coronary sinus (CS) tributaries in patients with ischemic and non-ischemic cardiomyopathy. Materials and methods Multidetector computed tomography (MDCT) was performed in 100 patients: 25 coronary artery bypass graft (CABG) patients with impaired left ventricular ejection fraction (LVEF), 25 CABG patients with preserved LVEF, 25 patients with non-ischemic cardiomyopathy, and 25 controls. The presence of the CS and its tributaries, including the posterior interventricular vein (PIV), posterolateral vein (PLV), left marginal vein (LMV), and the anterior interventricular vein (AIV) was assessed. Results The CS, PIV, and AIV were demonstrated in all patients, whereas presence of a PLV and LMV was identified in 68% and 48% of CABG patients with impaired LVEF, 96% and 68% of CABG patients with preserved LVEF, 92% and 80% of patients with non-ischemic cardiomyopathy, and 100% and 80% of controls ( p = 0.001 and 0.046 for PLV and LMV, respectively). Conclusions This is the first report to demonstrate that the posterolateral vein and left middle vein, branches of the coronary sinus, are detectable in a significantly smaller number of CABG patients with impaired LVEF compared to controls, CABG with preserved LVEF, and non-ischemic cardiomyopathy. The absence of CS tributary veins in ischemic cardiomyopathy potentially hinders proper lead implantation and results in suboptimal CRT response.

Background Pericallosal, or A2 bifurcation, aneurysms are an infrequently encountered cause of subarachnoid hemorrhage (SAH). While the International Subarachnoid Aneurysm Trial showed improved outcomes for patients with any ruptured anterior circulation aneurysm treated with embolization, there was also a higher recurrence rate for embolized aneurysms. Notably, there were relatively few pericallosal aneurysms. Objective Specific analysis of pericallosal aneurysms may help guide therapeutic decisions. Methods Retrospective analysis of patients who presented with proven saccular pericallosal aneurysms was performed at two institutions from 1999 to 2009. Patients were stratified according to presentation Hunt and Hess grades and modified Fisher scores, treatment modality and outcomes as well as development of vasospasm, hydrocephalus and required treatment. Results Eighty-eight patients with pericallosal aneurysms were identified. Sixty-two presented with SAH and 26 in elective fashion, 2 of whom had a prior history of SAH. Fifty-four patients underwent microsurgical repair and 32 endovascular repair. Patients presenting with SAH due to pericallosal aneurysm treated with an endovascular approach were more likely to have a good modified Rankin scale (mRS) (mRS 0–2 vs 3–6) (p=0.028), to make a complete recovery (mRS=0) (p=0.017) and were less likely to die (mRS=6) (p=0.026). Patients with electively treated pericallosal aneurysms did not have statistically significant differences in outcome between surgical and endovascular cohorts. Differences in secondary endpoints did not reach significance. Conclusion Patients with ruptured pericallosal aneurysms fare better with endovascular therapy, with better chance of complete recovery. Surgical and endovascular treatments of unruptured pericallosal aneurysms have similar results and outcome.

Objectives: We hypothesized that the extent of aortic atheroma of the entire thoracic aorta, determined by pre-operative multidetector-row computed tomographic angiography (MDCTA), is associated wi...

The purpose of this study was to investigate replacing unenhanced and arterial single-energy CT acquisitions after endovascular aneurysm repair with one dual-energy CT arterial acquisition.Thirty patients underwent arterial dual-energy CT (80 and 140 kVp) and venous single-energy CT (120 kVp) after endovascular aneurysm repair, and the radiation doses were compared with those of a standard triple-phase protocol. Both virtual unenhanced and arterial images were generated with dual-energy CT. Images were reviewed clinically for detection of endoleaks and evaluation of stent and calcium appearance. The aortic luminal attenuation on virtual unenhanced CT images was compared with that on previously acquired true unenhanced images. Virtual unenhanced, arterial, and venous images were compared for thrombus attenuation. Single-energy CT and dual-energy CT images were compared for noise.Replacement of two (unenhanced, arterial) of three single-energy CT acquisitions with one dual-energy CT acquisition resulted in 31% radiation dose savings. All images were clinically interpretable. Thoracic (32 +/- 2 vs 35 +/- 4 HU) and abdominal (30 +/- 3 vs 35 +/- 5 HU) aortic attenuation was similar on virtual unenhanced and true unenhanced images. Thrombus attenuation was similar on virtual unenhanced (32 +/- 6 HU), arterial phase (33 +/- 7 HU), and venous phase (34 +/- 6 HU) images. Decreased stent and calcium attenuation was observed at some locations on virtual unenhanced images. Noise in the thoracic (10 +/- 1 HU) and abdominal (12 +/- 2 HU) aorta was lower on virtual unenhanced images than on true unenhanced images (13 +/- 4 HU, 19 +/- 5 HU). Noise was comparable for dual-energy and single-energy CT (thorax, 16 +/- 2 vs 13 +/- 2 HU; abdomen, 21 +/- 3 vs 23 +/- 5 HU).Virtual unenhanced and arterial phase images derived from dual-energy CT can replace true unenhanced and arterial phase single-energy CT images in follow-up after endovascular aneurysm repair (except immediately after the procedure), providing comparable diagnostic information with substantial dose savings.

The objective of our study was to evaluate response assessment and predict clinical outcome in patients with metastatic renal cell carcinoma (RCC) receiving antiangiogenic targeted therapy. Target lesions were assessed on routine contrast-enhanced CT (CECT) images obtained during the portal venous phase using new response criteria.Standard CECT examinations of patients with metastatic clear cell RCC on first-line sunitinib or sorafenib therapy (n = 84) were retrospectively evaluated using Mass, Attenuation, Size, and Structure (MASS) Criteria; Response Evaluation Criteria in Solid Tumors (RECIST); Size and Attenuation CT (SACT) Criteria; and modified Choi Criteria. The objective response to therapy was compared with clinical outcomes including time to progression (TTP) and disease-specific survival. The Kaplan-Meier method was used to estimate survival functions.A favorable response according to MASS Criteria had a sensitivity of 86% and specificity of 100% in identifying patients with a good clinical outcome (i.e., progression-free survival of250 days) versus 17% and 100%, respectively, for RECIST partial response. The objective categories of response used by MASS Criteria-favorable response, indeterminate response, and unfavorable response-differed significantly from one another with respect to TTP (p0.0001, log-rank test) and disease-specific survival (p0.0001, log-rank test).Assessment of metastatic RCC target lesions on CECT for changes in morphology, attenuation, size, and structure by MASS Criteria is more accurate than response assessment by SACT Criteria, RECIST, or modified Choi Criteria. Furthermore, the use of MASS Criteria for imaging response assessment showed high interobserver agreement and may predict disease outcome in patients with metastatic RCC on targeted therapy.

The purpose of this HIPAA-compliant study was to prospectively evaluate the feasibility of contrast material–enhanced computed tomography (CT) with digital bone masking for the evaluation of synovitis and tenosynovitis in patients with rheumatoid arthritis. Four patients with rheumatoid arthritis and findings at magnetic resonance (MR) imaging were evaluated after informed consent for this institutional review board–approved study was obtained. To improve the conspicuity of synovial enhancement, postcontrast CT was performed with a relatively low kilovoltage and high iodine concentration and precontrast images were used as a subtraction mask to eliminate high-attenuation cortical bone contours. Moderate to high agreement between CT and MR imaging findings for synovitis and tenosynovitis was demonstrated, which suggests that this technique may be an acceptable alternative to MR imaging in the evaluation of rheumatoid arthritis. © RSNA, 2009

Summary: Purpose: Diffusion-weighted MR imaging (DWI) is a novel technique to delineate focal areas of cytotoxic edema of various etiologies. We hypothesized that DWI may also detect the epileptogenic region and adjacent areas during the ictal and early postictal periods in patients with temporal lobe epilepsy (TLE). Methods: We studied patients with intractable TLE (n = 9), due to hippocampal sclerosis (HS, n = 7), left mesial temporal lobe tumor (n = 1), and of unknown etiology (n = 1). Informed consent was obtained before inclusion in the study. All patients with single short seizures were scanned immediately after EEG-documented seizures (between 45 and 150 min); one of two patients in status was scanned 14 h after cessation of seizures. DWI results were analyzed visually and by calculating apparent diffusion coefficient (ADC) maps. Results: We found significant decreases in ADC postictally in one of six patients with TLE due to HS and single short seizures. One patient with an incompletely resected temporal lobe tumor also exhibited ADC abnormalities. One patient in focal status epilepticus revealed a decrease in ADC, and one patient with a continuous aura had no DWI abnormality. Conclusions: Postictal DWI technique may occasionally help delineate epileptic areas in some patients with TLE. Yield is low in patients with HS and single short seizures: it may be higher in patients with tumor or status epilepticus.

Background Noninvasive characterization of coronary atherosclerotic plaque is limited with current computed tomography (CT) techniques. Dual-energy CT (DECT) has the potential to provide additional attenuation data for better differentiation of plaque components. Objective We attempted to characterize coronary atherosclerotic plaque with DECT. Methods Seven human coronary arteries acquired at autopsy were scanned consecutively at 80 and 140 kVp with CT. Vessels were perfused with saline, and data were acquired before and after contrast agent injection. Lesions were identified, and attenuation measurements were made from CT image quadrants. CT quadrants were classified as densely calcified, fibrocalcific, fibrous, lipid-rich, or normal vessel wall, corresponding to matched histology images. Attenuation values at each peak tube voltage were compared within plaque types for both noncontrast and contrast scans. Further, dual-energy index (DEI) values computed from attenuation were analyzed for classification of plaque. Results In 14 lesions, a total of 56 quadrants were identified. Histology results classified 8 (14%) as densely calcified, 8 (14%) as fibrocalcific, 9 (16%) as fibrous, 5 (9%) as lipid-rich, and 25 (45%) as normal vessel wall. Calcified lesions attenuated significantly more at 80 kVp in both contrast and noncontrast scans, whereas fibrous plaque attenuated more at 80 kVp only for contrast-enhanced scans. No differences were found for lipid-rich plaques. Using DEI values, only densely calcified plaques could be distinguished from other plaque types except fibrocalcific plaques in contrast images. Conclusions Only densely calcified and fibrocalcific plaques showed a true change in attenuation at 80 versus 140 kVp. Therefore, calcified plaques could be distinguished from noncalcified plaques with DECT, but further classification of plaque types was not possible.

Left ventricular (LV) thrombus is a frequent and potentially dangerous complication of ischemic heart disease (IHD). We evaluated the clinical, imaging, and pathology characteristics of confirmed LV thrombus and compared the diagnostic value of contrast-enhanced magnetic resonance imaging (MRI) with transthoracic (TTE) and transesophageal echocardiography (TEE) for the diagnosis of LV thrombi.Between November 1997 and December 2003, 361 patients with IHD had surgical and/or pathological confirmation of presence or absence of LV thrombus. Clinical information and preoperative imaging study reports were retrospectively reviewed regarding detection of thrombus. Comparisons were made between clinical and imaging characteristics of patients with and without confirmed thrombus.Left ventricular thrombus was present in 106 (29%) of 361 patients in this study. Patients with thrombus had a higher incidence of recent embolic events (6.1% vs 0.8%, P.005). In 160 patients with all 3 imaging modalities performed within 30 days of surgical or pathological confirmation, contrast-enhanced MRI showed the highest sensitivity and specificity (88% +/- 9% and 99% +/- 2%, respectively) compared with TTE (23% +/- 12% and 96% +/- 3.6%, respectively) and TEE (40% +/- 14% and 96% +/- 3.6%, respectively) for thrombus detection.Left ventricular thrombus occurs frequently in patients with IHD and is associated with risk of systemic embolization. Contrast-enhanced MRI provided the highest sensitivity and specificity for LV thrombus when compared to TTE and TEE, and should be considered in the care of patients at high risk of LV thrombus formation.

Objectives: Exercise-induced QT/RR hysteresis exists when, for a given R-R interval, the QT interval duration is shorter during recovery after exercise than during exercise. We sought to assess the association between QT/RR hysteresis and imaging evidence of myocardial ischemia.Background: Because ischemia induces cellular disturbances known to decrease membrane action potential duration, we hypothesized a correlation between QT/RR and myocardial ischemia.Methods: We digitally analyzed 4-second samples of QT duration and R-R–interval duration in 260 patients referred for treadmill exercise stress and rest single photon emission computed tomography myocardial perfusion imaging; a cool-down period was used after exercise. None of the patients were in atrial fibrillation or used digoxin, and none had marked baseline electrocardiographic abnormalities. Stress and rest myocardial perfusion images were analyzed visually and quantitatively to define the extent and severity of stress-induced ischemia. QT/RR hysteresis was calculated using a computerized algorithm.Results: There were 82 patients (32%) who manifested myocardial ischemia by single photon emission computed tomography myocardial perfusion imaging. The likelihood of ischemia increased with increasing QT/RR hysteresis, with prevalence according to quartiles of 20%, 30%, 26%, and 49% (P = .003 for trend). In analyses adjusting for ST-segment changes, exercise capacity, heart rate recovery, and other confounders, QT/RR hysteresis was independently predictive of presence of myocardial ischemia (adjusted odds ratio for 100-point increase of QT/RR hysteresis, 1.61; 95% confidence interval, 1.22-2.12; P = .0008). QT/RR hysteresis was also predictive of severe ischemia.Conclusion: Exercise-induced QT/RR hysteresis is a strong and independent predictor of myocardial ischemia and provides additional information beyond that afforded by standard ST-segment measures.

Mitral regurgitation (MR) is a common complication of ischemic heart disease, and its presence portends adverse outcomes. As the exact mechanisms of ischemic MR are not well defined, we characterized left ventricular global geometry, regional function, and regional myocardial scarring, in addition to mitral valve apparatus geometry, using magnetic resonance imaging (MRI) of ischemic heart disease patients with left ventricular dysfunction and varying degrees of ischemic MR.Sixty patients with varying degrees of MR (none, mild, moderate, and severe) determined by echocardiography and referred for MRI assessment of ischemic heart disease were included. Left ventricular geometric, functional, and scar measurements in addition to mitral valve geometric measurements were evaluated.Clinical characteristics found to be significant predictors of degree of MR included severity of coronary artery disease (p0.05), completeness of myocardial perfusion (p0.005), and average systolic blood pressure (p0.05). Mitral systolic tenting area (p0.0001) in a statistical model with scarring of the anterior-lateral region (p0.05) proved to be the most powerful predictor of MR severity (r2 = 0.31). Mitral annular dilatation in the anterior-posterior direction (p0.0001) and diminished LV systolic function (p0.005) were important determinants of mitral systolic tenting area (r2 = 0.57).Mitral tenting in combination with regional left ventricular myocardial scarring are important mechanisms to the development of ischemic MR. Surgical annuloplasty addresses mitral tenting, but has little impact on the effect of regional scarring. Moderate-to-severe ischemic MR develops in patients with regional scarring of the anterior-lateral and inferior-posterior regions, and new surgical developments should take this into account.

Despite their advantages, percutaneous coronary interventional procedures are less effective in diabetic patients. Changes in the mechanical properties of vascular walls secondary to long-term hyperglycemia as well as other factors such as age may influence coronary distensibility. This investigation is aimed at deciphering the extent of these effects on distensibility of postmortem human coronary arteries in a controlled manner. Excised human left anterior descending (LAD) coronary arteries were obtained within 24 h postmortem. With the use of intravascular ultrasound, vascular deformation was analyzed at midregions of 51 moderate lesions. Intraluminal pressure was systematically altered using a computerized pressure pump system and monitored by a pressure-sensing guidewire. Distensibility, a normalized compliance term, was defined as the change in lumen area normalized by the initial reference area over a given pressure interval. With the use of multivariate analysis and repeated-measures ANOVA, coronary distensibility was independently influenced by hyperglycemia and age ( P < 0.05) through the entire pressure range. Within physiological pressure range, distensibility was significantly reduced with age in nonhyperglycemic coronary specimens (10.55 ± 4.41 vs. 6.99 ± 2.45, ×103 kPa−1, P = 0.01), whereas the hyperglycemic vessels were stiff even in the younger group (7.90 ± 5.82 vs. 7.20 ± 3.36, ×103 kPa−1, P = 0.79). Similar results were observed with stiffness index and elastic modulus of the arteries. Hyperglycemia and age independently influenced the distensibility of moderately atherosclerotic LAD coronary arteries. The stiffening with age was overshadowed in the hyperglycemic group by as-yet-undetermined factors.

Noncommunicating dissecting intramural hematoma is an aortic dissection variant, characterized by absent flow within the false lumen. Noncommunicating dissecting intramural hematoma is thought to be more stable than communicating dissection when beginning in the descending aorta. This study assessed clinical characteristics, anatomic characteristics, and 1-year outcomes in acute descending noncommunicating dissecting intramural hematoma versus communicating dissection.Retrospective database review identified patients who underwent magnetic resonance or computed tomography imaging revealing acute descending noncommunicating dissecting intramural hematoma or communicating dissection. Comparisons of clinical and anatomic characteristics and 1-year outcomes were performed.Twenty-four noncommunicating dissecting intramural hematoma and 36 communicating dissection cases were identified. Patients with noncommunicating dissecting intramural hematoma were older (68.5 +/- 8.8 versus 61.8 +/- 11.6 years; p0.05). Although noncommunicating dissecting intramural hematoma often showed abdominal aorta extension (50%), the infrarenal level was spared. Communicating dissection characteristically extended beyond the diaphragm (89%), including into the infrarenal aorta (28%). There was no significant difference in rates of adverse clinical events for noncommunicating dissecting intramural hematoma versus communicating dissection (13% versus 30%; 0.10p0.05). By follow-up imaging (87% of population), aortic deterioration was more frequent in noncommunicating dissecting intramural hematoma versus communicating dissection cases (60% versus 15%; p0.005).Acute descending noncommunicating dissecting intramural hematoma and communicating dissection represent two variants, with differing clinical and anatomic characteristics, but comparable levels of 1-year morbidity.

Purpose To characterize the extent and distribution of left ventricular myocardial scar in delayed enhancement magnetic resonance imaging (MRI). Materials and Methods Delayed enhancement images from 18 patients were categorized into three groups based on myocardial scar appearance: discrete myocardial infarction (N = 10), diffuse fibrosis (N = 4), and circumferential endocardial scarring (N = 4). Images were segmented manually by two observers (twice by one observer) to identify nonviable myocardium. Scar was characterized by the following morphologic parameters: the relative area of nonviable myocardium (Percent Scar); a measure of scar cohesion (Patchiness); and the extent to which scar traversed the ventricle wall (Trans>50). Results The three scar parameters successfully discriminated between patient groups, although no one parameter was able to differentiate between all groups. The average bias between readers was approximately 3% for each parameter, and the average bias between repeated measurements was 1%. In addition, five patients exhibited regions of nonhyperenhanced nonviable myocardium that were expected to show hyperenhancement based upon their location within the infarct zone and appearance on cine images. Conclusion Quantitative characterization of myocardial scar showed good interobserver and intraobserver agreement. However, the appearance of nonhyperenhanced scar in chronic ischemia is problematic for segmentation of delayed enhancement images. J. Magn. Reson. Imaging 2003;18:434–441. © 2003 Wiley-Liss, Inc.

Background Non-invasive identification and characterization of mildly stenotic atherosclerotic lesions is an increasingly important focus of coronary imaging. Design We examined the accuracy of mufti (16)-slice computed tomography (MSCT) for Imaging of these lesions In comparison with intravascular ultrasound (IVUS). Materials Mildly stenotic segments of the left coronary artery were identified by coronary angiography and analyzed using IVUS and contrast-enhanced MSCT. Independent reviewers evaluated the accuracy of MSCT for presence, composition and distribution of atherosclerotic plaque and remodeling response in comparison to IVUS using receiver operating characteristic (ROC) data analysis. Results Of 46 segments in 14 patients, diagnostic characterization by MSCT was possible in 37 (80.4%) segments. in these segments the accuracy of MSCT for identifying plaque presence, calcification, distribution and positive remodeling was consistently greater than 0.90 (reader 1) and 0.87 (reader 2). Conclusion State-of-the-art MSCT can accurately identify mildly stenotic coronary atherosclerosis and provide an assessment of morphology and remodeling response.

To evaluate segmented reconstruction algorithms for spiral multi-slice computed tomography (MSCT) that use data from two cardiac cycles to improve temporal resolution (tau) for imaging of the heart.An initial group of 78 cardiac patients (heart rates [HR] = 63-167 beats per minute [bpm]) were imaged on a 4-slice, 500 ms gantry rotation time scanner (scanner 1). Images were reconstructed with a single-segment algorithm using data from one cardiac cycle with a reconstruction window of fixed length (tau = 250 ms). Images were also reconstructed with two variants of a multi-segment algorithm using data from two cardiac cycles where only one end of the reconstruction window was fixed and the other end was freely moveable to allow adjustment of tau according to HR: (1) "2-segment fixed start" with fixed start of reconstruction, (2) "2-segment fixed end" with fixed end of reconstruction (for both, tau = 125-250 ms). The resulting image sets were ranked from best to worst (1-3, respectively) in a side-by-side, blinded comparison by two independent readers. A second group of 26 patients (HR = 74-90 bpm) were imaged on a 12-slice, 420 ms gantry rotation time scanner (scanner 2). Data were reconstructed with a single-segment algorithm (tau = 210 ms) and a "2-segment fixed start" algorithm (tau = 105-210 ms) and image sets were ranked from best to worst (1-2, respectively).There was no clear evidence that any one technique is superior for imaging on scanner 1. Reader 1 ranked single-segment images the highest for all HRs, but statistically significant differences among the three algorithms were only found for the lowest HRs (80 bpm), where reader 1 preferred single-segment over "2-segment fixed end" techniques (p = 0.048). The highest rankings given by reader 2 varied according to HR: single-segment images were superior for lowest HRs, while "2-segment fixed start" images were superior for HRs80 bpm; none of these comparisons reached statistical significance. Improved performance of 2-segment reconstruction was found with scanner 2. Both readers ranked "2-segment fixed start" images the highest (p0.01).The added value of 2-segment cardiac reconstruction algorithms for spiral MSCT was not demonstrated for a 4-slice, 500 ms gantry rotation time scanner but shown to be beneficial for a 12-slice, 420 ms gantry rotation time scanner in the crucial HR range of 74-90 bpm.

Rationale and Objectives In studies with small samples, the authors often encounter data sets in which the estimated area under the receiver operating characteristic (ROC) curve is 1.0. In such cases, neither asymptotic nor resampling methods provide a means of estimating the standard error or constructing a lower confidence bound. The purpose of this study was to develop tables for determining the approximate 95% lower confidence bound when the estimated ROC area is 1.0. Materials and Methods Using Monte Carlo simulation, the authors generated 10,000 data sets for each specification of sample sizes, ROC curve shape, and data format (continuous and ordinal scale). For each of these combinations the authors determined the 95% lower confidence bound. Results When the estimated ROC area is 1.0, the 95% lower confidence bounds differ dramatically depending on the shape of the ROC curve and on whether the test results are ordinal or continuous. Four tables of 95% lower confidence bounds are provided, along with guidelines for their use. Conclusion Given the different shapes of ROC curves and the different formats in which ROC data are collected, it is not feasible to offer one simple method of constructing confidence bounds that works for all ROC curves. The tables provided in this article are useful for interpreting studies with estimated ROC areas of 1.0.

Radiolucent foreign bodies (FBs) such as plastic objects and toys remain difficult to identify on conventional radiographs of the neck and chest. Children may present with a variety of respiratory complaints, which may or may not be due to a FB.To determine whether radiolucent FBs such as plastic LEGOs and peanuts can be seen in the tracheobronchial tree or esophagus using low-dose spiral CT, and, if visible, to determine the optimal CT imaging technique.Multiple spiral sequences were performed while varying the CT parameters and the presence and location of FBs in either the trachea or the esophagus first on a neck phantom and then a cadaver. Sequences were rated by three radiologists blinded to the presence of a FB using a single scoring system.The LEGO was well visualized in the trachea by all three readers (both lung and soft-tissue windowing: combined sensitivity 89 %, combined specificity 89 %) and to a lesser extent in the esophagus (combined sensitivity 31 %, combined specificity 100 %). The peanut was not well visualized (combined sensitivity35 %). The optimal technique for visualizing the LEGO was 120 kV, 90 mA, 3-mm collimation, 0.75 s/revolution, and 2.0 pitch. This allowed for coverage of the cadaver tracheobronchial tree (approximately 11 cm) in about 18 s. Although statistical power was low for detecting significant differences, all three readers noted higher average confidence ratings with lung windowing among 18 LEGO-in-trachea scans.Rapid, low-dose spiral CT may be used to visualize LEGO FBs in the airway or esophagus. Peanuts were not well visualized.

Rationale and Objectives. In assessing diagnostic accuracy it is often essential to determine the reader's ability both to detect and to correctly locate multiple abnormalities per patient. The authors developed a new approach for the detection and localization of multiple abnormalities and compared it with other approaches. Materials and Methods. The new approach involves partitioning the image into multiple regions of interest (ROIs). The reader assigns a confidence score to each ROI. Statistical methods for clustered data are used to assess and compare reader accuracy. The authors applied this new method to a reader-performance study of conventional film images and digitized images used to detect and locate malignant breast cancer lesions. Results. The ROI-based approach, the free-response receiver operating characteristic (FROC) curve, and the patient-based approach handle the estimation of the false-positive rate (FPR) quite differently. These differences affect the measures of the respective areas under the curves. In the ROI-based approach the denominator is the number of ROIs without a malignant lesion. In the FROC approach the average number of false-positive findings per patient is plotted on the x axis of the curve. In contrast, the patient-based approach mishandles the FPR by ignoring multiple detection and/or localization errors in the same patient. The FROC approach does not lend itself easily to statistical evaluations. Conclusion. The ROI-based approach appropriately captures both the detection and localization tasks. The interpretation of the ROI-based accuracy measures is simple and clinically relevant. There are statistical methods for estimating and comparing ROI-based estimates of accuracy.

The purpose of this study was to evaluate the potential benefits of performing vascular phase scanning of the kidneys in addition to unenhanced and parenchymal phase contrast-enhanced CT in patients being examined for urologic surgery.Parenchymal and vascular phase images from triphasic renal helical CT of 50 patients were sequentially evaluated in a randomized, retrospective fashion by two independent observers. The number of renal arteries and veins and the presence of vein or collecting system anomalies were recorded for each scan phase along with a subjective 10-point-scale score of the visibility of the vasculature and collecting system. Correlation of these findings was made with surgical or angiographic findings in 67 of the 87 kidneys and was made by consensus review in the remaining 20 kidneys.Accessory renal arteries were seen significantly more often (p.05, chi-square test) on the vascular phase scans. The subjective scores for the visibility of the renal arteries and renal veins were significantly higher on the vascular phase scans (p.0001, Wilcoxon's rank sum test). The subjective scores for the visibility of the filling of the collecting system and renal pelvis were significantly higher for the parenchymal phase scans, despite the use of a small contrast bolus before each scan (p.0001, Wilcoxon's rank sum test). CONCLUSION; Triphasic renal CT better reveals the artery and vein anatomy of the kidney than does parenchymal phase imaging only. Triphasic helical CT is indicated in patients undergoing planning for urologic surgery when vascular anatomy is clinically important.

To the Editor: In our previous article1 we used decision analysis to examine the cost-effectiveness of various test strategies for both screening and diagnosing carotid artery disease. While our conclusions for screening were contingent on several factors (ie, prevalence of significant stenosis, benefits and risk of surgery, and quality of life with stroke), for presurgical patients the best test strategy was clear. 3D time-of-flight (TOF) magnetic resonance angiography (MRA) is more cost-effective than catheter angiography (CA), as long as the MRA sensitivity and specificity are at least 86% and 90%, respectively. Missing from this analysis, however, was data on patient preference for CA or MRA. Swan and Langlotz2 point out that a patient’s attitude about an intervention is an essential component …

The purpose of this study was to subjectively compare the visibility of normal anatomy of the hands and feet using selenium-based digital radiography versus conventional film-screen (100-speed) radiography.Digital and film-screen images of the hands and feet of 24 patients were obtained without an antiscatter grid using identical X-ray exposure. Each pair of images was evaluated independently by five experienced radiologists for visibility of normal anatomy using a six-point rating scale. Soft tissues, cortical bone, and trabeculae were evaluated. For each observer, "equivalence" was defined as a mean difference in image quality of less than 1 unit on the 0-5 scale used in the study. Paired t tests were also performed to determine whether the average visibility rating of one technique was statistically superior to that of the other at a .05 level of significance for each observer and at each anatomic landmark.In all categories, selenium-based digital images were rated equivalent to film-screen images by the five observers. Using the sum of the nine landmarks, four of the five observers rated the quality of selenium-based digital images superior to that of film-screen images.Subjective visibility of normal anatomy of the hands and feet using selenium-based digital radiography was similar to that achieved using conventional film-screen radiography.

Transcatheter aortic valve implantation (TAVI) has become an emerging alternative for high-risk patients with aortic stenosis unsuitable for surgical intervention. We report the case of a 26-mm Edwards Sapien valve (Edwards Lifesciences, Irvine, CA) implanted into an insufficient 29-mm CoreValve prosthesis (Medtronic Inc, Minneapolis, MN) 1 year after implantation using the transapical approach in a 59-year-old man. Transesophageal echocardiography showed severe paravalvular regurgitation and computed tomography revealed the CoreValve to be located slightly below the aortic annulus with evidence of underdeployment. The balloon-expandable Sapien system caused a better expansion of the underdeployed CoreValve and the pericardial skirt adequately covered the leakage. The paravalvular regurgitation disappeared and the patient recovered.

Iterative reconstruction techniques (IRTs) may improve image quality for low-dose imaging compared with filtered back projection (FBP) reconstruction.We compared the results of an IRT for low-dose thoracic aortic computed tomography (CT) imaging with those from FBP reconstruction.Data from 50 patients who underwent 256-slice CT for evaluation of the thoracic aorta were reconstructed with FBP and an IRT (iDose(4)) at 3 noise-reduction strengths (levels 2, 4, and 6). A blinded reader graded image quality (scale, 1-5; 5 = high diagnostic confidence) and the extent of shoulder artifact (scale, 1-5; 5 = no artifact) on all reconstructions. A second reader evaluated a subset of 20 cases to determine interreader and intrareader reproducibility. The mean and SD of attenuation were measured at 5 locations along the thoracic aorta and both subclavian arteries.Image noise (SD of attenuation) improved with IRT relative to FBP (aorta: FBP, 31.4 ± 8.6 HU; IRT level 2, 25.1 ± 6.9 HU; level 4, 21.7 ± 6.2 HU; level 6, 17.2 ± 5.4 HU; P0.0001; subclavian arteries: FBP, 92.7 ± 34.6 HU; IRT level 2, 50.1 ± 17.1 HU; level 4, 48.9 ± 18.6 HU; level 6, 45.2 ± 19.2 HU; P0.0001), whereas mean attenuation was unchanged. Increasing image quality was observed in the aorta and through the shoulders as the contribution from IRT to the final images increased (P0.0001). Significant differences were noted between readers in image quality assessment of the aorta but not through the shoulders.IRT is associated with reduced noise and shoulder artifact and allows for low-dose aortic CT imaging.

Flow assessment with phase contrast magnetic resonance imaging (PC-MRI) protocols is an important component of a comprehensive cardiovascular MR (CMR) assessment. Breath-hold (BH) and non-breath-hold (NBH) PC-MRI protocols are widely available for this imaging modality. Because flow in the great vessels is known to vary with the respiratory cycle, we hypothesized that these 2 approaches might yield different results in the clinical assessment of forward and regurgitant flow in the ascending aorta. Further, given renewed awareness of the possible effect of velocity offsets in PC-MRI, we also sought to evaluate the impact of BH and NBH protocols on this potential source of error. A prospective observational study was performed in 55 consecutive patients referred for clinical CMR of the thoracic aorta. Both BH and NBH protocols were performed at the sinotubular junction and at the mid ascending aorta. Ten additional patients underwent repeated scanning at the mid ascending aorta with both BH and NBH protocols so that protocol variability could be assessed. Finally, ten patients were scanned with both BH and NBH protocols, and phantoms were then imaged with identical imaging parameters so that offset errors associated with each protocol could be evaluated. Forward flow was generally greater with the NBH protocol than with the BH protocol (mean values 102.1 mL vs. 97.9 mL; P = 0.0004). The Bland–Altman limits of agreement were quite wide for all indices (e.g, forward flow, −26.7 mL, +18.2 mL), which suggests that results from BH and NBH protocols cannot be interchanged with confidence. Estimated phase offset errors were similar for both protocols and were generally within acceptable ranges at the mid ascending level, with slightly higher values observed at the sinotubular junction for the BH technique. We observed differences in flow values with BH and NBH protocols for PC-MRI. This finding is relevant to patients imaged serially for the evaluation of cardiac output or valve (aortic or mitral) insufficiency, for whom adherence to one PC-MRI breathing protocol is likely most effective.

To evaluate clinical outcomes, pathologic subtypes, metastatic disease rate, and clinical features associated with malignancy in Bosniak category IIF and III cystic renal lesions.This retrospective study was institutional review board approved and HIPAA compliant. Informed consent was waived. Radiology and hospital information systems were searched for Bosniak IIF and Bosniak III lesions in computed tomographic (CT) reports from January 1, 1994 to August 31, 2009. Patients 18 years and older with unenhanced and contrast material-enhanced CT results and with lesions either surgically resected or with 1 year or more of surveillance were included. Data recorded were history of renal cell carcinoma, number of renal lesions, presence of a coexistent solid renal mass, surgical pathologic findings, and presence of metastatic disease from a renal malignancy. Sixty-two patients with 69 Bosniak IIF lesions and 131 patients with 144 Bosniak III lesions were identified. Proportions from independent groups were compared by using the Fisher exact test; continuous variables were compared by using a two-tailed two-sample t test or a Wilcoxon two-sample test.The malignancy rate of resected Bosniak IIF lesions was 25% (four of 16) and that for Bosniak III lesions was 54% (58 of 107) (P = .03). Thirteen percent (nine of 69) of Bosniak IIF lesions progressed at follow-up, and 50% (four of eight) of these resected cysts were malignant. History of primary renal malignancy, coexisting Bosniak category IV lesion and/or solid renal mass, and multiplicity of Bosniak III lesions were each associated with an increased malignancy rate in Bosniak III lesions. No patients developed locally advanced or metastatic disease from a Bosniak IIF or III lesion.Although the malignancy rate in surgically excised Bosniak IIF and Bosniak III cystic renal lesions was 25% and 54%, respectively, in our study, the malignancy rate was higher in patients with a history of primary renal malignancy or coexisting Bosniak IV lesion and/or solid renal neoplasm.

Background:ε-Aminocaproic acid (EACA) has been used to reduce the rate of cerebral aneurysm rerupture before definitive treatment. In centers administering EACA to patients with a subarachnoid hemorrhage (SAH), patients eventually diagnosed with angiographically negative subarachnoid hemorrhage (ANSAH) may also initially receive EACA, perhaps placing them at increased risk for ischemic complications.Objective:To evaluate the effect of short-term EACA on outcomes and secondary measures in patients with ANSAH.Methods:We conducted a retrospective study of 454 consecutive SAH patients over a 2-year period under a current protocol for EACA use. Patients were excluded if a source for the SAH was discovered, yielding a total of 83 ANSAH patients. The patients were assigned to groups that did or did not receive EACA. The primary end points of the study were ischemic complications, pulmonary emboli, vasospasm, ventriculoperitoneal shunting rates, and outcomes.Results:Statistical analysis yielded no significant difference between the 2 arms with respect to any of the end points: vasospasm (P = .65), deep vein thrombosis (P = .51), pulmonary embolism (P = 1.0), stroke (P = 1.0), myocardial infarction (P = 1.0), and ventriculoperitoneal shunt (P = .57). There was no statistically significant outcome difference using the modified Rankin Scale (P = .30).Conclusion:Short-term (

Because of varying treatment effectiveness with vascular endothelial growth factor (VEGF)-targeted therapy in patients with metastatic renal cell carcinoma (RCC), the association of prognostic pre-therapy clinical schema, initial post-therapy computed tomography (CT) findings, and combination thereof in predicting progression-free survival (PFS) was investigated. A predictive biomarker that combines clinical risk factors and CT imaging features associated with initial response to therapy would be useful in stratifying patients into risk groups to guide therapy, in designing and interpreting results of clinical trials, in planning risk-directed therapy, and in patient counseling. Early identification of poor responders using an imaging biomarker may reduce drug-related toxicity and cost and allow for a therapeutic intervention before disease burden significantly advances.For this institutional review board-approved HIPAA-compliant retrospective study, baseline data for 82 patients with metastatic RCC treated with sunitinib or sorafenib was obtained for risk stratification by Memorial Sloan Kettering Cancer Center (MSKCC) criteria and criteria by Heng et al. (J Clin Oncol 2009;27:5794-9), (described here as "VEGF prognostic factors criteria"). The initial post-therapy CT was evaluated by Response Assessment Criteria in Solid Tumors (RECIST), Choi criteria, and Morphology, Attenuation, Size, and Structure (MASS) criteria. Kaplan-Meier estimates of PFS (the reference standard) for each patient group and overall accuracy of each method and combined criteria were calculated.The MSKCC model, VEGF prognostic factors criteria, RECIST, MASS criteria, MSKCC + MASS criteria, and VEGF prognostic factors + MASS criteria each demonstrated significant differences in PFS among patient groups (P0.005 for each, Log-rank test). Stratification of patient groups by Choi criteria was not statistically significant with respect to PFS (P = 0.101). MSKCC + MASS criteria yielded the highest overall accuracy for identifying PFS ≥ 1 year (77%) and for identifying PFS1 year (77%).A combination of pre-therapy clinical risk factors and CT imaging response by MASS criteria more effectively predicted PFS in patients with metastatic RCC on VEGF-targeted therapy than any single method.

The primary objective of our study was to compare the effect of a chest radiography computer-aided detection (CAD) system on the follow-up recommendations of chest radiologists, general radiologists, and pulmonologists.A chest radiography CAD system (RapidScreen 1.1) that has been approved by the U.S. Food and Drug Administration (FDA) and a second-generation version of the system (OnGuard 3.0) not yet approved by the FDA were applied to single frontal radiographs of 200 patients at high risk for lung cancer. One hundred patients had actionable nodules (mean size, 16.9 mm) and 100 patients did not. Six chest radiologists, six general radiologists, and six pulmonologists independently interpreted each image first without CAD and then with CAD during blinded reading sessions. The frequency with which readers correctly referred patients for follow-up tests was measured. Differential effects based on nodule size, shape, location, density, and subtlety were tested with multiplevariable logistic regression.For patients without actionable lesions, pulmonologists showed an increase in their recommendations for follow-up from 0.46 unaided to 0.52 with CAD (p = 0.001), whereas chest and general radiologists had much lower average rates and were not affected by CAD's false marks (0.26 without CAD vs 0.25 with RapidScreen 1.1 and 0.26 with OnGuard 3.0, p ≥ 0.734). CAD improved all readers' detection of moderately subtle lesions (p = 0.013) but did not significantly increase follow-up rates overall for patients with actionable nodules (0.63 unaided vs 0.63 with RapidScreen 1.1, p = 0.795; and 0.63 unaided vs 0.64 with OnGuard 3.0, p = 0.187).The effect of CAD on readers' clinical decisions varies depending on the training of the reader. CAD did not improve the performance of chest or general radiologists. Nonradiologists are particularly vulnerable to CAD's false-positive marks.

To assess the utility of holodiastolic flow reversal (HDR) in the descending aorta on velocity-encoded cardiac magnetic resonance (MR) images in the stratification of aortic regurgitation (AR) severity.This study was approved by the institutional review board, with waiver of informed consent. A total of 80 patients (overall mean age, 49 years ± 18 [standard deviation]; 22 women and 58 men) with clinical indication for cardiac MR imaging of the aorta were analyzed retrospectively. Velocity-encoded MR imaging was used to quantify AR and assess for HDR at the level of the middescending aorta. These indexes were compared with a qualitative integrated echocardiographic evaluation of AR severity. Sensitivity and specificity for HDR in the prediction of substantial AR were determined, and logistic regression analysis (with associated odds ratios and C statistics) was performed, with HDR and regurgitant fraction as independent predictors. An additional 42 patients (overall mean age, 48 years ± 21; 12 female and 30 male) were then prospectively evaluated in similar fashion to evaluate a decision model derived from analysis of the first group.HDR predicted severe AR (echo grade, 4) with high sensitivity (100%) and specificity (93%). HDR was highly specific (100%) but had lower sensitivity (61%) for moderate to severe AR (echo grade, 3-4). Integration of HDR and direct AR quantification into a combined stratification model based on analysis of the primary group showed good predictive results in the validation group, with a C statistic of 0.94 for moderate to severe AR and 0.93 for severe AR.HDR in the middescending thoracic aorta observed at cardiac MR is indicative of severe AR and can be used in conjunction with quantified regurgitant values obtained from velocity-encoded MR imaging to stratify AR severity.

We hypothesized that the extent of aortic atheroma of the entire thoracic aorta, determined by pre-operative multidetector-row computed tomographic angiography (MDCTA), is associated with long-term mortality following nonaortic cardiothoracic surgery.In patients evaluated for cardiothoracic surgery, presence of severe aortic atheroma is associated with adverse short- and long-term post-operative outcome. However, the relationship between aortic plaque burden and mortality remains unknown.We reviewed clinical and imaging data from all patients who underwent electrocardiographic-gated contrast-enhanced MDCTA prior to coronary bypass or valvular heart surgery at our institution between 2002 and 2008. MDCTA studies were analyzed for thickness and circumferential extent of aortic atheroma in 5 segments of the thoracic aorta. A semiquantitative total plaque-burden score (TPBS) was calculated by assigning a score of 1 to 3 to plaque thickness and to circumferential plaque extent. When combined, this resulted in a score of 0 to 6 for each of the 5 segments and, hence, an overall score from 0 to 30. The primary end point was all-cause mortality during long-term follow-up.A total of 862 patients (71% men, 67.8 years) were included and followed over a mean period of 25 ± 16 months. The mean TPBS was 8.6 (SD: ±6.0). The TPBS was a statistically significant predictor of mortality (p0.0001) while controlling for baseline demographics, cardiovascular risk factors, and type of surgery including reoperative status. The estimated hazard ratio for TPBS was 1.08 (95% confidence interval: 1.045 to 1.12). Other independent predictors of mortality were glomerular filtration rate (p = 0.015), type of surgery (p = 0.007), and peripheral artery disease (p = 0.03).Extent of thoracic aortic atheroma burden is independently associated with increased long-term mortality in patients following cardiothoracic surgery. Although our data do not provide definitive evidence, they suggest a relationship to the systemic atherosclerotic disease process and, therefore, have important implications for secondary prevention in post-operative rehabilitation programs.

The aim of this study was to improve response assessment in patients with metastatic renal cell carcinoma (RCC) on antiangiogenic targeted therapy by evaluating changes in both tumor size and attenuation and by detecting unique patterns of contrast enhancement on contrast-enhanced CT (CECT).Tumor long-axis measurements and volumetric mean tumor attenuation of target lesions on CECT images were correlated with time to progression in 53 patients with metastatic clear cell RCC treated with first-line sorafenib or sunitinib. The frequencies of specific patterns of tumor progression were assessed. The data were used to develop new imaging criteria, the size and attenuation CT (SACT) criteria. CECT findings were evaluated using the SACT criteria, Response Evaluation Criteria in Solid Tumors (RECIST), and modified Choi criteria, and the Kaplan-Meier method was used to estimate survival functions.One or more target metastatic lesions had decreased attenuation ofor=40 HU in 59% of patients with progression-free survival of250 days (n=44) after initiating targeted therapy; 0% of patients with earlier disease progression (n=9) had this finding. A favorable response based on SACT criteria had a sensitivity of 75% and specificity of 100% for identifying patients with progression-free survival of250 days, versus 16% and 100%, respectively, for RECIST and 93% and 44% for the modified Choi criteria.Objectively measuring changes in both tumor size and attenuation on the first CECT study after initiating targeted therapy for metastatic RCC markedly improves response assessment. Distinct patterns of disease recurrence are seen in patients with metastatic RCC on targeted therapy.

Rationale and Objectives The goal of many multiple-observer computer-aided detection (CADe) studies is to estimate the change in observers' diagnostic performance with CADe from their unaided performance. A key issue in these studies is the method for estimating the observers' unaided performance. The crossover design is considered the most valid. The sequential design takes less time and is less expensive but may be biased. We conducted a study to investigate the differences between these two designs. Materials and Methods Data from two large CADe studies using both types of unaided reads were analyzed. The first study involved three radiologists examining the chest x-rays of 200 patients for lung nodules. The second study involved 19 observers interpreting the computed tomography colonography images of 100 patients for polyps. Observers' sensitivity, specificity, and receiver operating characteristic areas were estimated while unaided in both designs and compared to their accuracy with CADe. Bias, inter-observer variability, and correlations between unaided and aided results were assessed. Results Observers tend to perform better while unaided in the sequential design than while unaided in the crossover design, but the differences are small. The inter-observer variability is larger in the sequential design. The correlations between unaided and aided results are larger in the sequential design. 95% CIs for the change with CADe are narrower with the sequential design. Conclusion The estimated effect of CADe on observer performance is similar regardless of the study design. Use of the sequential design may save investigators time and resources.

Hypothesis Humeral version is highly variable in human beings. Accurate assessment of humeral version may allow for more anatomic reconstruction at shoulder arthroplasty. Two-dimensional (2D) computed tomography (CT) has been used to measure humeral version but has limitations of poor interobserver reproducibility and strict dependence on arm positioning during image acquisition. This study evaluated a new technique, 3-dimensional (3D) volume rendering, for measuring humeral version. Materials and methods Eight dried human humerus specimens were included in the study. Gold standard measurements of humeral version were obtained by use of metallic beads and fluoroscopy. The specimens were then scanned at CT in 2 different positions, 1 neutral to the table and 1 angled at 20°. The image data sets were used to measure humeral version in each bone with both the standard 2D technique and the new 3D technique. Measurements were performed by 3 readers at 2 different time points. Readers were blinded to the gold standard results and each others' measurements. Results For all readers, 3D measurements averaged within 4.3° of the gold standard. For 2 of the 3 readers, 3D measurements were more accurate than 2D measurements. For all 3 readers, intraobserver variability was better with the 3D technique. For all reader pairs, interobserver variability was better with the 3D technique. Conclusions This study shows a 3D volume-rendering CT technique to measure humeral version accurately and consistently that is independent of patient positioning.

To create a model to estimate glomerular filtration rate (GFR) in healthy individuals, such as renal transplant donors, by using renal volume measurements derived from multidetector computed tomographic (CT) scans, serum creatinine level, height, weight, race, and age, and to compare the performance of this kidney volume-based model with the modification of diet in renal disease (MDRD) equation.This HIPAA-compliant retrospective study was approved by the institutional review board; informed consent was waived. Age, sex, height, weight, race, serum creatinine level, and measured GFR were recorded from 244 individuals who underwent renal donor evaluation over a 2-year period. An automated segmentation algorithm was used to measure renal parenchymal volume from CT images. GFR was measured by using urinary clearance of iodine 125 ((125)I) iothalamate. Analysis of covariance was used to model GFR measured by using (125)I-iothalamate clearance from the significant variables. The model was tested in 100 different renal donors and performance was compared with performance of the MDRD equation.Renal volume, age, serum creatinine level, and weight (P.001) significantly correlated with GFR measured by using (125)I-iothalamate clearance. Sex (P = .6), race (P = .9), and height (P = .76) were not significant. The fitted regression model was GFR(EUn) = 70.77 - 0.444 A + 0.366 W + 0.200 V(R) - 37.317 Cr (r(2) = 0.57), where GFR(EUn) is estimated unadjusted GFR in milliliters per minute, A is age in years, W is weight in kilograms, V(R) is mean total renal volume in milliliters, and Cr is serum creatinine value in milligrams per deciliter (micromoles per liter). Correlation between renal volume-based GFR and GFR measured by using (125)I-iothalamate clearance was +0.42. The model outperformed the MDRD equation in six of six measurements.A model for estimating GFR that incorporates renal volume correlated well with measured GFR and outperformed the MDRD equation in potential living renal donors; this model could be used to estimate donor GFR from CT scans instead of measuring it by using (125)I-iothalamate clearance.

The aim of the study was to determine if patients with hypertrophic cardiomyopathy (HCM), both with and without myocardial fibrosis, have altered aortic stiffness as assessed by magnetic resonance imaging (MRI) pulse wave velocity (PWV) measurements.Abnormal aortic stiffness implies an unfavorable prognosis and has been established in a variety of aortic diseases and ischemic cardiomyopathy. However, the relationship between aortic stiffness and HCM has not been studied previously.The study was institutional review board approved and Health Insurance Portability and Accountability Act of 1996 compliant. Velocity-encoded MRI was performed in 100 HCM and 35 normal control subjects. PWV was determined between the mid-ascending and -descending thoracic aorta. Delayed-enhancement MRI was acquired for identification of myocardial fibrosis.Mean age was 52.4 years in HCM and 45.3 years in control subjects. The prevalence of myocardial fibrosis in HCM was 70%. PWV was significantly higher in HCM patients compared with control subjects (8.72 +/- 5.83 m/s vs. 3.74 +/- 0.86 m/s, p0.0001). PWV was higher (i.e., increased aortic stiffness) in HCM patients with myocardial fibrosis than in those without (9.66 +/- 6.43 m/s vs. 6.51 +/- 3.25 m/s, p = 0.005).Increased aortic stiffness, as indicated by increased PWV, is evident in HCM patients, and is more pronounced in those with myocardial fibrosis. Further, aortic stiffening may adversely affect left ventricular performance. In addition, increased aortic stiffness correlates with myocardial fibrosis, and may represent another potentially important parameter for risk stratification in HCM, warranting further study.

Objectives:In patients with chronic ischemic heart disease, the relationship between coronary artery lesion severity and myocardial scarring is unknown.The purpose of this study was to examine the relationship between proximal coronary artery stenosis severity, the amount of coronary collateralization, and myocardial scar extent in the distal distribution of the affected coronary artery based on both quantitative coronary angiography (QCA) and delayed-enhancement magnetic resonance imaging (DE–MRI).Methods:Thirty-four patients (26 males, 8 females; age range: 35-86 years) with a coronary artery containing a single, proximal stenosis ≥30% by quantitative coronary angiography (QCA) underwent DE-MRI. The relationship between stenosis severity, collateralization, and myocardial scar morphology (area, transmurality and patchiness) was examined using linear mixed-model ANCOVA.Results:There was a statistically significant correlation between stenosis severity and scar extent (r=0.53, pConclusions:Using QCA and DE-MRI, we demonstrate a significant relationship between coronary artery stenosis severity and myocardial scar extent, in the absence of a documented history of acute infarction. The relationship likely reflects increasing ischemia leading to scar formation in the range of angiographically significant stenosis. However, in the absence of collateralization, scar was observed without significant stenosis, especially in females.

We assessed the correlation between reduced renal function and parenchymal volume following partial nephrectomy.In 21 of 42 patients with tumors in a solitary kidney who were enrolled in a study measuring function before and after surgery underwent computerized tomography, and measurement of the glomerular filtration rate and estimated glomerular filtration rate (the latter at baseline and 2 to 6 months) before and after surgery. A segmentation algorithm was used to measure renal parenchymal volume. The percent of renal parenchymal volume loss was correlated with the percent loss in glomerular filtration rate using the Pearson correlation coefficient.Mean +/- SD net preoperative volume was 284 +/- 67 cc (range 179 to 413) and mean net postoperative volume was 240 +/- 61 cc (range 119 to 346) with an absolute functional volume loss of between 5 and 160 cc. The average percent of parenchymal volume loss was 15% (range -2% to 47%). The mean loss of the measured glomerular filtration rate 3 days postoperatively was 33.9% (range -70.7% to 74.4%) and the estimated glomerular filtration rate 2 to 6 months postoperatively was 19.7 % (-6.0% to 45.5%). There was a low degree of correlation between the percent volume loss and the percent measured glomerular filtration rate loss at 3 days (r = 0.28, p = 0.22). However, there was a moderate degree of correlation between the percent volume loss and the percent estimated glomerular filtration rate loss at 2 to 6 months (r = 0.48, p = 0.03).In patients with partial nephrectomy the renal parenchymal volume loss correlates best with the renal function loss several months after surgery. Estimates of volume loss may be useful for predicting postoperative renal function when planning partial nephrectomy in patients with a solitary kidney.

Objective: To develop patient-specific contrast injections for uniform enhancement of cardiovascular multidetector row computed tomography (MDCT) images. Methods: Sixty-two patients were imaged using electrocardiogram (ECG)-gated spiral MDCT. Thirty patients (group 1) received a uniphasic injection; the remaining 32 patients (group 2) received patient-specific multiphasic injections. For group 2 patients, the vasculature between injection and imaging sites was considered a "gray box" whose transfer function was determined from a test bolus injection and the resulting enhancement in the left side of the heart. This transfer function was used to determine the injection necessary to achieve 250 Hounsfield units in the left side of the heart. Intraindividual and interindividual variation of enhancement were determined for both groups. Superior vena cava (SVC) artifacts were graded on a 4-point scale. Results: The measured indices of intraindividual variation were significantly smaller in group 2 than in group 1 (P < 0.05), indicating improved uniformity with patient-specific injections. The interindividual variation of mean enhancement in group 2 was smaller than in group 1, but the difference was not significant. The severity of SVC artifacts was significantly reduced (P < 0.05) for thinner patients (

Surgical left ventricular reconstruction improves symptoms and potentially prognosis in patients with ischemic cardiomyopathy; however, the effects of reconstruction on myocardial mechanics are not well defined. Therefore, we have computed left ventricular rotation and torsion in patients undergoing left ventricular reconstruction to determine its effects on these quantitative measures of myocardial mechanics.Magnetic resonance imaging with tissue grid-tagging was performed in 26 patients (19 male/7 female, 62 +/- 11 years) (mean +/- standard deviation) before (23 +/- 29 days) and after (231 +/- 106 days) left ventricular reconstruction, as well as in 7 healthy volunteers (5 male/2 female, 34 +/- 7 years). Left ventricular rotation was computed at basal and apical short-axis levels; torsion was defined as the difference between apical and basal rotation.Before left ventricular reconstruction, maximal apical rotation was significantly impaired relative to that of healthy volunteers (P = .001), although maximal basal rotation was preserved (P = .84). After reconstruction, maximal torsion did not change significantly: torsion was 6 degrees +/- 3 degrees both before and after reconstruction (P = .84). However, the rate of early diastolic untwist improved significantly after reconstruction (-18 degrees/s +/- 13 degrees/s vs -23 degrees/s +/- 14 degrees/s; P = .04). Furthermore, patients with relatively worse torsion before reconstruction demonstrated more improved function after reconstruction; patients with torsion of less than 6 degrees (n = 12) showed greater improvement in ejection fraction (15% vs 6%; P = .005), torsion (1 degrees vs -1 degrees; P = .01), and diastolic untwist (-9 degrees/s vs -25 degrees/s; P.001) than did patients with torsion of 6 degrees or more (n = 14).Torsional mechanics were severely impaired by ischemic cardiomyopathy. On average, left ventricular reconstruction did not affect systolic torsion generation significantly; however, patients with relatively worse torsion did show improvement. Furthermore, the rate of untwist improved after surgery, suggesting that diastolic function was improved.

Background Misclassification of study endpoints in randomized clinical trials of screening tests has been well documented, yet its effect on study power, type I error rate, and risk ratio estimate have not been studied in depth. Methods We constructed a Markov model to depict the natural history of disease and the effect of screening on it. Using this model we simulated subjects in a two-arm RCT. We varied the type and amount of misclassification, and studied the effect on two endpoints — disease-specific mortality and the incidence of disease-specific symptoms. Results Failure to identify disease-specific events in a RCT of screening has a small effect on the risk ratio estimate and study power. In contrast, the false identification of events as being attributable to the target disease greatly reduces study power. Conclusions Investigators of RCTs of screening tests should carefully consider the potential for misclassification and the type of misclassification that their study is as risk for. Studies should be designed to minimize misclassification. The effect of misclassification on power should be considered in sample size calculations.

To retrospectively evaluate with dynamic magnetic resonance (MR) imaging the changes in global and regional left ventricular (LV) function after surgical ventricular restoration (SVR) performed in chronic ischemic heart disease patients with large nonaneurysmal or aneurysmal postmyocardial infarction zones.The study was performed with institutional review board approval, and a waiver of individual informed consent was obtained. The study was HIPAA compliant. Patients (83 men, 22 women; mean age, 61 years +/- 9 [standard deviation]) were evaluated with MR imaging before and after SVR as follows: pre-SVR examination (n = 105; 25 days +/- 39 before SVR; median, 7 days; range, 1-189 days), early post-SVR examination (n = 95, 7 days +/- 3 after SVR), and late post-SVR (n = 35, 313 days +/- 158 after SVR). Cine MR imaging allowed calculation of ejection fraction and rate-corrected velocity of circumferential fiber shortening (Vcf(C)) for global LV functional evaluation, whereas tagged MR imaging (spatial modulation of magnetization with harmonic phase analysis) permitted assessment of regional circumferential strain (E(C)) with coronary distribution. Vcf(C) and E(C) were computed at both LV base- and mid-LV short-axis levels remote from the site of anteroapical SVR.Prior to SVR, LV dilatation and diminished global and regional LV function were observed. At early post-SVR examination, Vcf(C) had improved significantly but E(C) showed a worsening trend overall, although only E(C )of the right coronary artery at the mid-LV level worsened significantly. At late post-SVR examination, Vcf(C) values were improved when compared with pre-SVR values, although E(C) showed no statistically significant improvement. When compared with that at early post-SVR examination, however, E(C) showed significant improvement in two segments: left anterior descending artery and right coronary artery at mid-LV level.Although volume-based indexes of global LV function improve significantly after SVR, regional LV function did not improve significantly; there was evidence of continued LV remodeling after SVR.

The objective of this study was to investigate the effect of contrast injection on atherosclerotic coronary plaque attenuation measured using multidetector-row computed tomography.Recent multidetector-row computed tomography studies have described the characterization of coronary atherosclerotic plaque on the basis of Hounsfield unit values. The influence of contrast injection on the attenuation of individual plaque components, however, is unknown.Using a pressurized perfusion system, 10 human coronary arteries were examined postmortem with multidetector-row computed tomography and histology. Pre-enhanced, peak-enhanced, and delayed enhanced multidetector-row computed tomography images were acquired during continuous perfusion of the vessel. A total of 37 focal atherosclerotic plaques were identified. Vessel wall attenuation was measured from multidetector-row computed tomography images during all three enhancement phases. On the basis of the histology, plaques were categorized as noncalcified (predominantly fibrous or predominantly fibrofatty), mixed calcified (calcified fibrous or calcified necrotic core), or densely calcified. The mean Hounsfield unit was compared among contrast phases for all plaques and in plaque subgroups.We observed contrast enhancement of atherosclerotic plaques within the vessel wall. For noncalcified plaques including both fibrous and fibrofatty plaques, the mean Hounsfield unit of the vessel wall during and after contrast injection exceeded the mean value before injection (t-test, P0.002).The present study demonstrates that intra-arterial injection of iodinated contrast agent results not only in luminal enhancement but also in atherosclerotic plaque enhancement in pressure-perfused coronary arteries imaged ex vivo. Plaque enhancement should be considered when characterizing plaque components on the basis of Hounsfield unit with multidetector-row computed tomography.

This study was performed by using an institutional review board–approved protocol, with waived informed consent and HIPAA compliance. The purpose of this study was to preliminarily evaluate a cine delayed-enhancement (DE) pulse sequence for depiction of wall motion and myocardial scar extent during a single acquisition. The technique is based on inversion-recovery single-shot balanced steady-state free precession magnetic resonance imaging. Cine DE images were acquired in 26 patients (18 men, eight women; age range, 25–84 years; mean age, 61 years ± 13 [standard deviation]). Image contrast was consistent throughout each series. Overall (ie, with both readers' scores averaged), the cine DE imaging–depicted wall motion was scored correctly in 71% of myocardial segments. Scar extent was scored correctly in 76% of segments; in no patient was scarring missed. Cine DE imaging is a promising technique for simultaneous visualization of wall motion and myocardial scar extent. © RSNA, 2006

Congenital heart disease (CHD) is a significant cause of morbidity and mortality in pediatric patients. Traditional teaching holds that specific types of CHD can be diagnosed on the chest radiograph (CXR) through pattern recognition. To determine the accuracy of radiologists in detecting CHD on the CXR. This study was a blinded retrospective review of chest radiographs from 281 patients (

Purpose. To define the relationship between left ventricular (LV) regional contractile function and the extent of myocardial scar in patients with chronic ischemic heart disease and multi-vessel coronary artery disease. Methods. Twenty-three patients with chronic ischemic heart disease and 5 healthy volunteers underwent magnetic resonance imaging (MRI). In patients, the relative area (Percent Scar) and transmural extent (Transmurality) of myocardial infarction were computed from short-axis delayed enhancement images. In each image, myocardial segments were categorized based on the extent of infarction they contained, with 6 categories each for Percent Scar and Transmurality: normal, from healthy volunteers; and 0%; 1–25%, 26–50%, 51–75%, and > 76% from patients. In patients and volunteers, regional LV function was quantified by absolute systolic wall thickening from cine images and midwall circumferential strain using tagged images. Results. Compared to normal segments, regional LV function in patients was significantly diminished in all scar extent intervals, with wall thickening 1 mm and strain 8% for all categories. Systolic wall thickening was reduced significantly in all categories above 50% Percent Scar and above 25% Transmurality in patients, relative to corresponding 0% categories. Circumferential strain was significantly reduced above 25% Percent Scar and above 25% Transmurality. Conclusions. In patients with chronic ischemic heart disease and multivessel coronary artery disease, wall thickening was more sensitive to changes in scar Transmurality than to changes in Percent Scar. However, circumferential strain was equally sensitive to both indices. In general, circumferential strain was more sensitive than wall thickening to increases in scar extent.

The potential clinical impact of variability in the measurement of coronary artery calcification with sequential MDCT was evaluated using Agatston, volume, and mass scoring algorithms.Fifty-six patients were imaged twice using an identical prospectively ECG-triggered sequential scanning protocol. The Agatston, volume, and mass scores were computed by two observers independently. In addition, a patient's total Agatston score was referenced to an age- and sex-stratified database to determine a percentile ranking. Interscan, interobserver, and intraobserver variability and the resultant impact on patients' risk stratifications were assessed.Significant interscan differences were found for all mean coronary calcium scores (Wilcoxson's signed rank test, p0.0001). Although the median percentage of interscan variability was low for all scoring methods, the interquartile range was wide, indicating significant variability in the data. Median scores (lower quartile-upper quartile) for observers 1 and 2, respectively, were as follows: Agatston, 5% (0-79%) and 6% (0-83%); volume, 12% (0-51%) and 12% (0-57%); and mass, 14% (0-57%) and 14% (0-58%). Interobserver and intraobserver differences between mean calcium scores were not significant, and consequently, lower interobserver and intraobserver variabilities (narrow interquartile ranges of 0-5%) were observed for all scores. Despite significant interscan differences in calcium scores, the percentile ranking assigned to the two scans differed in only 13% of patients. Interobserver differences resulted in a change in the percentile ranking in 7-9% of patients, whereas intraobserver differences caused a change in only 5% of patients.The accuracy of sequential MDCT for coronary calcium quantification is sufficient in most cases for stratification of patient risk.