Diagnostic yield of CT pulmonary angiography for pulmonary embolism in clinically suspected patients

Abstract

Pulmonary embolism (PE) is a common medical problem. Its diagnostic criteria must be reviewed to determine the need for confirmatory testing. Computed tomography pulmonary angiography (CTPA) is the current standard of care, which provides accurate diagnosis with rapid turnaround. This study aimed to estimate the diagnostic yield of CTPA in clinically suspected PE patients in a tertiary care hospital in Saudi Arabia. Radiology records of all patients with clinically suspected PE who underwent CTPA between January 1, 2012 and September 30, 2018 were reviewed retrospectively. A radiologist with 10 years of professional experience interpreted and reported all cases. The Wells score with 2 tiers (likely and unlikely) was used to raise the clinical suspicion of PE. Positive results for PE were reported in 177 out of 534 clinically suspected cases (33%). Among the positive PE cases, 143 were acute (81%) and 34 (19%) were chronic. Bilateral, right-sided, and left-sided PE were found in 115 (65%), 37 (21%), and 25 (14%) cases, respectively. Involvement of the segmental branches, subsegmental branches, and the pulmonary trunk were noted in 152 (86%), 70 (40%), and 9 cases (5%), respectively. Saddle PE was found in (4%) of the cases. The lower lobe branches (right 55%, left 53%) and the upper lobe branches (right 47%, left 41%) were the most common sites of involvement. CTPA had a higher positive detection rate for PE among clinically suspected cases than its published diagnostic yield. Adequate clinical evaluation when selecting patients for CTPA is emphasized to minimize unjustified exposure of the patients to radiation and intravenous contrast administration. It is crucial for radiologists to provide detailed reports commenting on all relevant findings, including pertinent negatives. A template for reporting radiological findings for CTPA can be recommended for this purpose.

Diagnostic Yield of CT Pulmonary Angiogram in the Diagnosis of Pulmonary Embolism and Its Predictive Factors

“…Unjustified CTPAs expose patients to unnecessary radiation, endangering them with the stochastic risk of radiation-induced malignancy [ 15 ]. Besides exposing patients to the risks of radiation, CTPA also carries potential adverse effects from intravenous contrast administration, such as contrast-induced nephropathy [ 11 ]. For each CTPA performed, a patient is exposed to a risk of up to 14% of contrast-induced nephropathy and a lifetime malignancy risk of 2.8% [ 15 ].…”

“…There is a wide range of diagnostic yields for CTPA for PE in the literature, ranging from 4.7% to 31% [3][4][5][6][7][8][9][10][11][12]. Despite using a lower cut-off (10%) as the acceptable threshold in North America, there are a few studies that report a yield lower than the threshold [3][4][5][6][7][8][9][10][11][12]. In Malaysia, we adopt the threshold of 15.4% as the acceptable rate for the yield of CTPA, as recommended by the Royal College of Radiologists [10,24].…”

“…With the advancement of medical technology, computed tomography pulmonary angiography (CTPA) has become the reference standard to diagnose PE [6][7][8][9][10]. CTPA can be performed in patients with suspected PE within minutes, and it has high sensitivity and specificity [11][12][13]. The sensitivity and specificity of CTPA in diagnosing PE range between 96% and 100% and between 89% and 98%, respectively [14].…”

“…The sensitivity and specificity of CTPA in diagnosing PE range between 96% and 100% and between 89% and 98%, respectively [14]. Nevertheless, the advancement of medical imaging also comes with the problem that clinicians may be over-reliant on CTPA to rule out PE [6][7][8][9][10][11][12][13][14][15][16]. This is evidenced by the increasing number of CTPAs ordered and the decreasing yield of CTPAs performed [6][7][8][9][10][11][12][13][14][15][16].…”

The relationship between pulmonary artery obstruction index and troponin in thorax computed tomography in pulmonary embolism

“…There are studies in which it is asserted that the benefits of thoracic computerized tomography (CT) angiography in pulmonary embolism are far greater than supposed. One helpful tool in this regard is the pulmonary artery obstruction index (PAOI), which is used to measure the degree of obstruction of the pulmonary arteries in thoracic CT angiography (5). The PAOI is a simple and reproducible index, and the number of studies conducted on it has increased in recent years.…”