Faculty Bibliography

PURPOSE: The aim of the study was to compare the prognostic value of right ventricular (RV) dysfunction detected on computed tomography pulmonary angiography (CTPA) and transthoracic echocardiography (TTE) in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: From all consecutive CTPAs performed between August 2003 and May 2010 that were positive for acute PE (n=1744), those with TTE performed within 48 hours of CTPA (n=785) were selected as the study cohort. Multivariate logistic regression analysis was performed to assess the association of CTPA RV/left ventricular (LV) diameter ratio and TTE RV strain with PE-related 30-day mortality, including other associated factors as covariates. The predictive ability (area under the curve) was compared between the model including the CT RV/LV diameter ratio and that including TTE RV strain. Test characteristics of the 2 modalities were calculated. RESULTS: Both CT RV/LV diameter ratio and TTE RV strain were independently associated with PE-related 30-day mortality (adjusted odds ratio=1.14, P=0.023 for 0.1 increment of the CT RV/LV diameter ratio; and odds ratio=2.13, P=0.041 for TTE RV strain). History of congestive heart failure and malignancy were independent predictors of PE-related mortality, while there was significantly lower mortality associated with anticoagulation use. The model including TTE RV strain and that including CT RV/LV had similar predictive ability (area under the curve=0.80 vs. 0.81, P=0.50). The sensitivity, specificity, and positive and negative predictive values of TTE RV strain and CT RV/LV diameter ratio at a cutoff of >/=1.0 were similar for PE-related 30-day mortality. CONCLUSIONS: Both RV strain on TTE and an increased CT RV/LV diameter ratio are predictors of PE-related 30-day mortality with similar prognostic significance.

PURPOSE: To evaluate the correlation between the computed tomography (CT)-derived right ventricle (RV) to left ventricle (LV) diameter ratio and the RV size determined by echocardiography in patients with acute pulmonary embolism. MATERIALS AND METHODS: Consecutive CT pulmonary angiography examinations (August 2003 to May 2010) from a single, large, urban teaching hospital were retrospectively reviewed. For a cohort of 777 subjects who underwent echocardiography within 48 hours of the CT acquisition, the qualitative RV size (divided into 5 categories) extracted from the echocardiography report was correlated with the CT-derived RV/LV diameter ratio. RESULTS: There was moderate correlation (Spearman rank correlation coefficient=0.54, P<0.001) between the CT-derived RV/LV ratio and the RV size as determined by echocardiography. The correlation coefficient and the concordance rate were inversely related to the time difference between the acquisitions of the 2 modalities. CONCLUSIONS: CT and echocardiography findings to assess the RV size after acute pulmonary embolism have moderate correlation.

OBJECTIVE: The purpose of this article is to describe the image acquisition, identification, and reporting of postoperative adhesions in patients undergoing CT for "redo sternotomy" surgical planning. CONCLUSION: Adhesions appear as linear fibrous bands that join structures in the mediastinum viewed on static images. Confirmation by cine imaging shows deformation of mediastinal structures. Identification and reporting of adhesions will likely guide surgeons to safer interventions.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is an established alternative to surgery for patients with severe, symptomatic aortic stenosis who are not suitable candidates for surgical replacement of the aortic valve. The computed tomography (CT) technologist has a critical role in the care of patients undergoing TAVR. Because image acquisition and postprocessing for TAVR planning are highly complex, it is important for CT technologists involved in the planning to understand clinical detail, protocols, potential pitfalls, and factors that may influence workflow. PURPOSE: To describe, from the CT technologist's point of view, the details of CT angiography acquisition and postprocessing at 1 institution for patients being screened for TAVR. DISCUSSION: For TAVR patients, CT image acquisition and postprocessing is essential for a successful intervention. It is clinically essential to maintain and execute a detailed, standardized imaging approach. CONCLUSION: TAVR planning is among the most complex procedures in radiology. For these patients, meticulous image acquisition and image postprocessing protocols are paramount, and successful patient outcomes depend on attention to clinical detail, protocols, potential pitfalls, and factors that may influence workflow.

PURPOSE: To introduce a new power injection technology that generates data as a digital imaging and communications in medicine (DICOM) image linked to individual patient imaging studies. In addition, to determine the fraction of patients in a subject cohort whose contrast injection data was captured as a DICOM image and to analyze contrast injection properties for those patients. METHODS: Over a 1-month period, authors performed a retrospective evaluation of 242 patients' consecutive contrast-enhanced computed tomography (CT) studies from a single 320-detector CT scanner in an academic radiology department. Authors gathered unique patient and examination identifiers, prescribed and injected contrast and saline volumes, prescribed and injected flow rate, and mean and maximum injection pressures. The literature was reviewed for the initial description of power injectors in radiology. RESULTS: Of the 242 CT studies evaluated, 98% had contrast injection data amended to the radiology images. For all patients, the mean volume of residual contrast was 5 mL. The differences between the prescribed and actual flow rate were small. Three patients reached the maximum pressure of 300 psi. There were no contrast extravasations. Discussion The most clinically relevant finding was that the injector and software system generated a detailed report of contrast administration. In 98% of the cases, this report was incorporated into the patient's permanent medical record and was available to the radiologist via a single DICOM image. CONCLUSION: Contrast injection data can be captured in DICOM format and reliably attached to a clinical contrast-enhanced CT image set for radiologist use.

PURPOSE: To evaluate variability in right ventricular-to-left ventricular (RV/LV) diameter ratios introduced by differences in measurement methods and the subsequent influence on the accuracy of predicting outcomes for patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: For 200 consecutive computed tomography pulmonary angiograms positive for acute PE, RV/LV diameter ratios were retrospectively measured using 3 different 4-chamber reformations and from axial images alone. The first 4-chamber reformation method (4ch-1) was a single oblique technique using LV morphology landmarks; the other 2 methods (4ch-2 and 4ch-3) were double oblique techniques that created an intermediate short-axis image to identify the maximum RV diameter but with different approaches to reach short-axis images. Interobserver variability was measured using 30 cases. Receiver-operating characteristic analysis compared the accuracy of predicting outcomes among the 4 measurements for PE-related death, and for death or the need for intensive therapies (composite outcome). RESULTS: The difference in median RV/LV diameter ratios was insignificant among 4ch-2 (1.01), 4ch-3 (1.02), and axial (1.03) datasets, whereas that from 4ch-1 (0.93) was significantly lower (P<0.001). Correlation between observers was excellent for all 4 datasets (r=0.881 to 0.925). Compared with 4ch-1, the other 3 datasets equally achieved higher accuracy in predicting PE-related 30-day mortality (area under curve: 0.55 vs. 0.69 to 0.73, P=0.007 to 0.019) and a composite outcome (area under curve: 0.65 vs. 0.77 to 0.78, P=0.003 to 0.010). CONCLUSIONS: Double oblique 4-chamber reformation methods that use intermediate short-axis images to optimize RV size predict outcomes better in patients with acute PE than do single oblique methods using only LV landmarks; however, their accuracy is not superior to that from measurements based on axial images.

To retrospectively evaluate prognostic accuracy of subjective assessment of right ventricle (RV) enlargement on CT pulmonary angiography (CTPA) images in comparison with objective measures of RV enlargement in patients with acute pulmonary embolism (PE). For 200 consecutive patients with acute PE, two readers blinded to patient outcomes subjectively determined whether the maximum RV diameter was greater than that of the left ventricle (LV) using axial CTPA images. For the objective measurements, RV/LV diameter ratios were calculated using axial images and 4-chamber reformatted images. For all assessments, sensitivities and specificities for predicting PE-related death within 30-days and a composite outcome including PE-related death or the need for intensive therapies were compared. The agreement between two readers was 91.5% (kappa = 0.83) and all other assessments had pair-wise agreement over 75% (kappa = 0.53-0.72). There was no significant difference in sensitivity between the subjective and objective methods for predicting both outcomes. The specificity for subjective RV enlargement (55.4-67.7%) was significantly higher than objective measures (45.8-53.1%), except for the 4-chamber views where, for one reader, the specificity of the subjective evaluation was higher but did not reach statistical significance. Complex measurements of RV/LV diameter ratios may not be needed to maximize the prognostic value from CTPA. The radiologist who interprets the CTPA images should report RV enlargement when the RV diameter subjectively appears larger than the LV.

Hutchinson-Gilford progeria syndrome is a rare, segmental premature aging syndrome of accelerated atherosclerosis and early death from myocardial infarction or stroke. This study sought to establish comprehensive characterization of the fatal vasculopathy in Hutchinson-Gilford progeria syndrome and its relevance to normal aging. We performed cardiovascular assessments at a single clinical site on the largest prospectively studied cohort to date. Carotid-femoral pulse wave velocity was dramatically elevated (mean: 13.00+/-3.83 m/s). Carotid duplex ultrasound echobrightness, assessed in predefined tissue sites as a measure of arterial wall density, was significantly greater than age- and sex-matched controls in the intima-media (P<0.02), near adventitia (P<0.003), and deep adventitia (P<0.01), as was internal carotid artery mean flow velocity (P<0.0001). Ankle-brachial indices were abnormal in 78% of patients. Effective disease treatments may be heralded by normalizing trends of these noninvasive cardiovascular measures. The data demonstrate that, along with peripheral vascular occlusive disease, accelerated vascular stiffening is an early and pervasive mechanism of vascular disease in Hutchinson-Gilford progeria syndrome. There is considerable overlap with cardiovascular changes of normal aging, which reinforces the view that defining mechanisms of cardiovascular disease in Hutchinson-Gilford progeria syndrome provides a unique opportunity to isolate a subset of factors influencing cardiovascular disease in the general aging population.