Pulmonary atelectasis: a frequent alternative diagnosis in patients undergoing CT-PA for suspected pulmonary embolism

Abstract

The purpose of the study was to evaluate the prevalence of atelectasis as an alternative diagnosis in patients who underwent computed tomographic pulmonary angiography (CT-PA) for suspected pulmonary embolism (PE), and to contrast the pathophysiology of pulmonary atelectasis and PE, both of which are associated with dyspnea and hypoxemia. We retrospectively identified 144 consecutive emergency department patients (n=49) and inpatients (n=95) admitted between July 2001 and June 2002 who were evaluated with CT-PA for suspected PE. There were 98 women and 46 men with a mean age of 58 years (range 27-95 years). Each CT report was reviewed for PE, the words "atelectasis," "collapse," and/or "volume loss," findings known to predispose to atelectasis, and alternative diagnoses. CT scans of those with PE and those with atelectasis were reviewed. Each case was categorized into one of three groups, as follows: group 1, PE; group 2, atelectasis of three or more segments and no PE; group 3, neither PE nor atelectasis. PaO2 was documented, when available (n=115), with PaO2 >100 mmHg recorded as 100 mmHg. Reports for group 3 were reviewed for alternative diagnoses. Thirteen percent of the study population (19/144, group 1) had PE, and two of them had concomitant atelectasis; mean PaO2 was 69 mmHg (range 38-100 mmHg). Nineteen percent of the study population (27/144, group 2) had atelectasis of three or more segments without PE; mean PaO2 was 73 mmHg (range 45-100 mmHg). Sixty-eight percent of the study population (98/144, group 3) had neither PE nor atelectasis; mean PaO2 was 79 mmHg (range 36-100 mmHg). There was a significant difference in the PaO2 between groups 1 and 3 (Student's t-test), with group 2 intermediate. Seventy percent of group 2 (19/27) had at least one finding predisposing to atelectasis: central bronchial abnormality (n=6), moderate or larger pleural effusion (n=11), pleural mass, pneumothorax, elevated hemidiaphragm, and severe kyphosis (the last four all n=1 each), versus 16% (3/19) of group 1 ( P<0.05). Sixty-three percent of group 3 (62/98) had one or more alternative diagnoses on CT that explained the patient's symptoms as follows: pneumonia (28%, 27/98), other lung disease (18%, 18/98), congestive heart failure (13%, 13/98), and malignancy (13%, 13/98). Pulmonary atelectasis was common in patients undergoing CT-PA for suspected PE, equaling pneumonia as the most common alternative diagnosis. Most patients with atelectasis had predisposing findings on CT. Pulmonary atelectasis and PE cause similar symptoms by different mechanisms of ventilation-perfusion mismatch.

Increased Emergency Department Computed Tomography Use for Common Chest Symptoms Without Clear Patient Benefits

“…Furthermore, with the escalating rates of CT utilization, a high number of clinically significant incidental findings have been reported, 6 which has led some physicians to argue that CT is useful in patients even when clinical suspicion of more concerning diagnoses (eg, PE) is high. 17,18 However, our results differ from previous studies in that no significant change in incidental findings was discovered during the period of increased CT utilization. Our results are not directly comparable with other findings, however, because they probably represent a lower risk population and are derived from a national sample versus a single institution where radiologists may report differently because of the local medicolegal environment.…”

The Prevalence of Clinically Relevant Incidental Findings on Chest Computed Tomographic Angiograms Ordered to Diagnose Pulmonary Embolism

“…[1][2][3] Radiographic findings supporting potential alternative diagnoses, especially infiltrates and pleural effusions, were found in up to 31% of our cohort. However, a substantial number of infiltrates that were not evident on chest x-ray films may be of limited clinical significance.…”

The analysis of non-thromboembolic findings encountered in multidetector computed tomography pulmonary angiography studies in patients with suspected pulmonary embolism

“…[13,22,23] Klinik olarak pnömo-nik infiltrasyonlar ile pulmoner embolinin oluşturduğu dispne, taşipne, plörotik göğüs ağrısı ve hipoksemi gibi semptomlar birbirine oldukça benzerlik göstermektedir. Kabrhel ve ark.…”

“…[1,[6][7][8][9][10] ÇKBT pulmoner anjiyografinin pulmoner emboli değerlendirmesinde kullanılan konvansiyonel anjiyografi ve ventilasyon/Perfüzyon (V/P) sintigrafisi gibi diğer görüntüleme yöntemlerine olan en önemli avantajlarından birisi bu görüntüleme yönteminin pulmoner vasküler inceleme yanında parankimal, mediastinal, kardiyak, plevral yapıların, toraks duvarı ve üst batın organlarının bir bütün olarak değerlendirilmesine olanak sağlamasıdır. [6,[11][12][13] Çünkü pulmoner emboli şüphesi ile tıbbi görüntüleme yapılan hastaların ancak %8-20'lik bölümünde pulmoner emboli saptanırken geriye kalan büyük bir hasta kitlesinde diğer patolojiler altta yatan neden olarak karşımıza çıkmakta-dır. [1,6,7,11,14,15] Biz bu araştırmada, pulmoner emboli ön tanısı ile ÇKBT pulmoner anjiyografi tetkiki yapılan olgularda pulmoner emboli sıklığını belirlemeyi ve emboli saptanmayan olgularda tanıya katkı sağlayan diğer bulguları analiz etmeyi amaçladık.…”