Linda B. Haramati

Computed tomography of partial anomalous pulmonary venous connection in adults

Objectives To systematically describe the imaging features and clinical correlates of a partial anomalous pulmonary venous connection diagnosed on computed tomography (CT) in adults. Methods Twenty-nine adults with a partial anomalous pulmonary venous connection on CT were retrospectively identified. There were 19 women and 10 men, with a mean age of 53 (range: 19–83) years. Four cases were identified by review of 1825 consecutive chest CT reports from July 2000–July 2001, and 25 cases were culled from chest radiology teaching files at 3 institutions. Inclusion criteria were availability of CT images and medical charts. Chest radiographs (25 of 29 cases) were reviewed for mediastinal contour abnormalities, heart size, and pulmonary vascular pattern. Chest CT scans were reviewed for location, size, and drainage site of the anomalous vein; presence or absence of a pulmonary vein in the normal location; cardiac size and configuration; and pulmonary vasculature. Charts were reviewed for evidence of pulmonary and cardiovascular disease, history of congenital heart disease, and results of other cardiac imaging. Results The prevalence of a partial anomalous pulmonary venous connection was 0.2% (4 of 1825 chest CT reports). Seventy-nine percent (23 of 29 patients) had an anomalous left upper lobe vein connecting to a persistent left vertical vein, only 5% (1 of 23 patients) of whom had a left upper lobe vein in the normal location. Seventeen percent (5 of 29 patients) had an anomalous right upper lobe vein draining into the superior vena cava, 60% (3 of 5 patients) of whom also had a right upper lobe pulmonary vein in the normal location. One patient (3%) had an anomalous right lower lobe vein draining into the suprahepatic inferior vena cava. Chest radiographic findings were abnormal left mediastinal contour in 64% (15 of 25 patients), abnormal right mediastinal contour in 8% (2 of 25 patients), and cardiomegaly in 24% (6 of 25 patients). Computed tomography findings were cardiomegaly in 48% (14 of 29 patients), right atrial enlargement in 31% (9 of 29 patients), right ventricular enlargement in 31% (9 of 29 patients), and pulmonary artery enlargement in 14% (4 of 29 patients). Pulmonary or cardiovascular symptoms were present in 69% (20 of 29 patients), 55% (11 of 20 patients) of whom had specific alternative diagnoses (excluding congestive heart failure and pulmonary hypertension) to explain the symptoms. Only 1 patient (3%) was diagnosed with a secundum atrial septal defect. Conclusions A partial anomalous pulmonary venous connection was seen in 0.2% of adults on CT. In contrast to previous series focusing on children, the anomalous vein in adults was most commonly from the left upper lobe, in women, and infrequently associated with atrial septal defects.

Increased diagnosis of pulmonary embolism without a corresponding decline in mortality during the CT era.

AIM To determine the association between the increasing computed tomography (CT) use for suspected pulmonary embolism (PE) on the annual rates of PE diagnosis and mortality, using time as a surrogate for CT use. MATERIALS AND METHODS New York States (NYS) Statewide Planning and Research Cooperative System (SPARCS) database was used to determine the rate of PE diagnosis and mortality between 1 January 1994 and 31 December 2004. Risk factors for PE were investigated. Bivariate and multivariate analyses were performed to determine the relationships between variables. RESULTS The study population consisted of 24,871,131 NYS patients. The number of patients with a primary diagnosis of PE nearly doubled over the study period, from 2590 in 1994 to 4920 in 2004, while total admissions remained stable. PE deaths did not vary significantly over time, from 157 in 1994 to 159 in 2004 and did not vary with the diagnoses of PE. Age-adjusted multivariate analysis did not reveal a significant association between the rates of PE diagnosis or mortality and corresponding risk factors. CONCLUSION This study suggests that the increased use of CT in patients with suspected PE has led to an increase in the diagnosis of PE without a corresponding decline in mortality. Further evidence, using data on individual patients, is needed to determine the appropriate role of CT in evaluating patients with suspected PE.

Radiological and clinical findings in acute and chronic exogenous lipoid pneumonia.

Purpose To describe the radiologic and clinical findings in a group of patients with exogenous lipoid pneumonia focusing on features that differentiate the acute and chronic presentations. Materials and Methods We retrospectively identified 15 patients from a single institution with exogenous lipoid pneumonia 1992–2001. Inclusion criteria were: imaging with chest CT and either CT features diagnostic of lipoid pneumonia or intrapulmonary lipids on pathologic examination. Each chart was reviewed for the clinical presentation, history of ingestion/exposure, predisposing factors, treatment and response to therapy. Initial (n = 13) and follow-up (n = 11) chest radiographs were reviewed for the patterns and distribution of lung parenchymal abnormalities and pleural effusion. Initial (n = 15) and follow-up (n = 7) CT scans were reviewed for lung parenchymal abnormalities (consolidation, ground glass opacities, linear/nodular opacities, masses, and crazy paving), presence or absence of fat attenuation, and pleural effusion. The groups were compared using the Fischer exact test. Results Nine patients had acute lipoid pneumonia, 7 males and 2 females with a mean age of 45 (range 4.5–81) years. Six patients had chronic lipoid pneumonia, 4 men and 2 women with a mean age of 63 (range 37–83) years. 78% (7/9) of patients with acute and all of the patients with chronic presentations had a known ingestion and/or a predisposing condition associated with lipoid pneumonia. On chest radiographs, consolidation and lower lobe involvement were present in the majority of patients with acute and none of the patients with chronic presentations. On CT, consolidation and fat attenuation were present in the majority of patients with each presentation. However, masses were present in 67% (4/6) of patients with chronic and none of the patients with acute presentation (P < 0.05). 86% (6/7) of patients with acute presentation had improvement on follow-up chest radiograph in contrast to none of the patients with chronic presentation (P < 0.05). 75% (3/4) of patients with acute lipoid pneumonia had improvement on follow-up CT in contrast with 67% (2/3) of patients with chronic lipoid pneumonia who had progression on follow-up CT. Conclusions The imaging features of acute and chronic lipoid pneumonia overlap with consolidation and lower lobe involvement present in both groups. However, only the patients with acute lipoid pneumonia had pleural effusions and improvement on follow-up. Only the patients with chronic lipoid pneumonia had pulmonary masses.

Variants and anomalies of thoracic vasculature on computed tomographic angiography in adults.

Objective: To determine the prevalence and clinical significance of normal, variant, and anomalous branching patterns of the aortic arch and the central veins on computed tomographic (CT) angiography in adults. Methods: We retrospectively reviewed 1000 consecutive CT angiograms of the chest in 658 women and 342 men with a median age of 53 years. Results: A total of 65.9% of patients had both normal aortic arch branching patterns and normal venous anatomy. Variants in the aortic arch branching pattern were present in 32.4% and anomalies in 1.5%. Venous anomalies were present in 0.7%. Review of CT reports showed that cardiothoracic radiologists correctly reported the anomaly more frequently than other radiologists (94% vs 20%, P = 0.003). Conclusions: Whereas anomalies of the central thoracic vasculature are uncommon, variants in the aortic arch branching pattern are common. An appreciation of the appearance of these entities on CT angiography allows for precise reporting and is useful in preprocedure planning.

Computed tomography evaluation of right heart dysfunction in patients with acute pulmonary embolism

Purpose: To evaluate the role of qualitative assessment of right heart dysfunction on multidetector computed tomography (CT) in patients with acute pulmonary embolism. Methods: Seventy-four consecutive adults with pulmonary embolism diagnosed on multidetector nongated CT were identified between July 2002 and March 2004. There were 47 women and 27 men, with a mean age of 62 years. Each CT scan was jointly reviewed by 2 of 3 reviewers in consensus. The CT scans were qualitatively assessed for dilatation of the right ventricle and the position of the interventricular septum. Scans were considered positive for right heart dysfunction if, on visual integration of multiple axial images, the right ventricle was dilated or the interventricular septum was straightened or bowed into the left ventricle. The extent of pulmonary vascular obstruction was graded using the CT clot burden scoring system. Reports of echocardiograms (n = 30) were reviewed when available. The sensitivity and specificity of CT and echocardiography in demonstrating right heart dysfunction were calculated and compared using pulmonary vascular obstruction of ≥30% as the reference standard. Results: Sixty-six percent (49 of 74 patients) with pulmonary embolism had right heart dysfunction on CT, with right ventricular dilatation in 38 patients and septal straightening or bowing in 44 patients. Forty-nine percent (36 of 74 patients) had pulmonary vasculature obstruction of ≥30%. There was a significant difference between the mean clot burden of patients with (12.8) and without (7.5) right heart dysfunction on CT (P = 0.0021). The sensitivity and specificity of CT in demonstrating right heart dysfunction were 81% (29 of 36 patients) and 47% (18 of 38 patients), respectively. Forty-one percent (30 of 74 patients) had technically adequate echocardiograms within 48 hours of CT. Fifty-seven percent (17 of 30) of the echocardiograms were positive for right heart dysfunction. There was no significant difference between the mean clot burden of patients with (12.7) and without (10.3) right heart dysfunction on echocardiography. Echocardiography had a sensitivity of 56% (10 of 17 patients) and a specificity of 42% (5 of 13 patients) in demonstrating right heart dysfunction. Conclusion: Qualitative assessment of the cardiac chambers is a quick and practical means of evaluating for right heart dysfunction on CT. Computed tomography findings of right heart dysfunction in patients with acute pulmonary embolism compare favorably with echocardiography and correlate with a higher mean pulmonary arterial clot burden. Because most patients do not undergo echocardiography, chest CT often provides the only opportunity to evaluate for right heart dysfunction in patients with acute pulmonary embolism.

ACR Appropriateness Criteria® acute chest pain--suspected pulmonary embolism.

Pulmonary embolism (PE) remains a common and important clinical condition that cannot be accurately diagnosed on the basis of signs, symptoms, and history alone. In the absence of high pretest probability and with a negative high-sensitivity D-dimer test, PE can be effectively excluded; in other situations, diagnostic imaging is necessary. The diagnosis of PE has been facilitated by technical advancements and multidetector computed tomography pulmonary angiography, which is the major diagnostic modality currently used. Ventilation and perfusion (V/Q) scans remain largely accurate and useful in certain settings. Lower-extremity ultrasound can substitute by demonstrating deep vein thrombosis; however, if negative, further studies to exclude PE are indicated. In all cases, correlation with the clinical status, particularly with risk factors, improves not only the accuracy of diagnostic imaging but also overall utilization. Other diagnostic tests have limited roles. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The development and review of the guidelines include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Pulmonary Embolism Diagnosis and Mortality With Pulmonary CT Angiography Versus Ventilation-Perfusion Scintigraphy: Evidence of Overdiagnosis With CT?

OBJECTIVE The purposes of this study were to determine whether pulmonary emboli diagnosed with pulmonary CT angiography (CTA) represent a milder disease spectrum than those diagnosed with ventilation-perfusion (V/Q) scintigraphy, to determine the trends in incidence and mortality among patients with the diagnosis of pulmonary embolism from 2000 to 2007, and to correlate incidence and mortality trends with imaging modality trends. MATERIALS AND METHODS Diagnoses of pulmonary embolism from 2000 to 2007 at an urban academic medical center were retrospectively identified. Patient data were collected from the hospital database and the Social Security Death Index. Incident diagnoses, type of imaging used, and date of death were documented. Bivariate and multivariate analyses were used to explore the relations between imaging use and the incidence and mortality of pulmonary embolism. Logistic regression analysis was used to estimate the odds of death of pulmonary embolism diagnosed with pulmonary CTA versus V/Q scintigraphy. RESULTS The cases of 2087 patients (1361 women, 726 men; mean age, 61.8 years) with pulmonary embolism were identified. From 2000 to 2007 the incidence of pulmonary embolism increased from 0.69 to 0.91 per 100 admissions in strong correlation with increased use of pulmonary CTA. There was no change in mortality, but the case-fatality rate decreased from 5.7% to 3.3%. On average, pulmonary emboli diagnosed with pulmonary CTA were one half as lethal as those diagnosed with V/Q scintigraphy (odds ratio, 0.538; 95% CI, 0.314-0.921). CONCLUSION The results of this study are evidence that the shift in imaging from V/Q scintigraphy to pulmonary CTA resulted in increased diagnosis of a less fatal spectrum of pulmonary embolic disease, raising the possibility of overdiagnosis. Outcome-based clinical trials with long-term follow-up would be helpful to further guide management.

Effect of HIV status on chest radiographic and CT findings in patients with tuberculosis

AIM To compare the chest radiographic and chest CT findings of tuberculosis according to HIV status. PATIENTS AND METHODS Ninety-eight HIV-tested patients with cultures positive for Mycobacterium tuberculosis (Mtb) between January 1991 and December 1993 whose clinical charts and radiographic records were available for review formed the study population. There were 67 HIV-positive patients (51 men, 16 women) and 31 HIV-negative patients (23 men, 8 women). Chest CT scans were available for review in 15 HIV-positive and four HIV-negative patients. RESULTS On chest radiographs, HIV-positive patients had mediastinal lymphadenopathy (60% vs. 23%) and atypical infiltrates (55% vs. 10%) significantly more frequently than HIV-negative patients. Conversely, HIV-negative patients had infiltrates typical for reactivation tuberculosis (77% vs. 30%) and cavitation (52% vs. 18%) significantly more frequently than HIV-positive patients. The chest CT scans showed a similar trend, but significant differences were only seen regarding more frequent bilateral mediastinal lymphadenopathy in HIV-positive patients and more frequent cavitation in HIV-negative patients. CONCLUSION This study demonstrates significant differences in chest radiographic and chest CT appearances of tuberculosis according to HIV status. HIV-positive patients have more frequent atypical infiltrates and mediastinal lymphadenopathy, and less frequent cavitation and infiltrates typical for reactivation tuberculosis than do HIV-negative patients.

Success of a Safe and Simple Algorithm to Reduce Use of CT Pulmonary Angiography in the Emergency Department

OBJECTIVE The purpose of our study was to determine whether the radiation exposure to patients with suspected pulmonary embolism (PE) could be decreased by safely increasing the use of ventilation-perfusion (V/Q) scanning and decreasing the use of CT pulmonary angiography (CTPA) through an educational intervention. MATERIALS AND METHODS Collaborative educational seminars were held among the radiology, nuclear medicine, and emergency medicine departments in December 2006 and January 2007 regarding the radiation dose and accuracies of V/Q scanning and CTPA for diagnosing PE. To reduce radiation exposure, an imaging algorithm was introduced in which emergency department patients with a clinical suspicion of PE underwent chest radiography. If the chest radiograph was normal, V/Q scanning was recommended, otherwise CTPA was recommended. We retrospectively tallied the number and results of CTPA and V/Q scanning and calculated mean radiation effective dose before and after the intervention. False-negative findings were defined as subsequent thromboembolism within 90 days. RESULTS The number of CTPA examinations performed decreased from 1,234 in 2006 to 920 in 2007, and the number of V/Q scans increased from 745 in 2006 to 1,216 in 2007. The mean effective dose was reduced by 20%, from 8.0 mSv in 2006 to 6.4 mSv in 2007 (p < 0.0001). The patients who underwent CTPA and V/Q scanning in 2006 were of similar age. In 2007, the patients who underwent V/Q scanning were significantly younger. There was no significant difference in the false-negative rate (range, 0.8-1.2%) between CTPA and V/Q scanning in 2006 and 2007. CONCLUSION The practice patterns of physicians changed in response to an educational intervention, resulting in a reduction in radiation exposure to emergency department patients with suspected PE without compromising patient safety.

Radiation Exposure From Medical Imaging in Patients With Chronic and Recurrent Conditions

PURPOSE Advances in medical imaging have been associated with increased utilization and increased radiation exposure, especially for patients with chronic and recurrent conditions. The authors estimated the cumulative radiation doses from medical imaging for specific cohorts with chronic and recurrent conditions. METHODS All patients diagnosed with hydrocephalus (n = 1,711), pulmonary thromboembolic disease (n = 3,220), renal colic (n = 5,855), and cardiac disease (n = 11,072) from January 1, 2000, to December 31, 2005, were retrospectively identified. Each imaging examination that used ionizing radiation from 2000 to 2008 was incorporated into an estimate of total effective dose and organ-specific doses. Patients with high levels of radiation exposure after 3 years (total effective dose > 50 mSv; dose to the ocular lens > 150 mSv) were identified. RESULTS The mean estimated effective doses for the surviving diagnostic cohorts after 3 years were 12.3 mSv for patients with hydrocephalus, 21.7 mSv for those with pulmonary thromboembolic disease, 18.7 mSv for those with renal colic, and 14.0 mSv for those with cardiac disease. Among patients with hydrocephalus, 26.3% (339 of 1,291) had radiation doses > 150 mSv to the ocular lens within 3 years. In all cohorts, the proportion of patients with total effective doses > 50 mSv within 3 years was significantly higher for those diagnosed in 2004 and 2005 than for those diagnosed in 2000 and 2001. CONCLUSION Patients with hydrocephalus, pulmonary thromboembolic disease, renal colic, and cardiac disease received radiation exposures that may put them at increased risk for cancer. Moreover, the proportion who received estimated total effective doses > 50 mSv within 3 years was significantly higher for those diagnosed most recently. It is the responsibility of institutions and physicians to critically evaluate their infrastructures, diagnostic strategies, and imaging techniques for each individual patient, with an eye toward minimizing cumulative medical radiation exposure.