The Effect of Imaging Modality on Patient Management in the Evaluation of Pulmonary Thromboembolism

Abstract

A retrospective medical record review was performed to study the differences in clinical risk profiles and the relationships between test results versus management for suspected pulmonary thromboembolism (TE) in patients undergoing either radionuclide ventilation perfusion (V/Q) scans or pulmonary computed tomographic angiography (CTA), as the initial test. Data of 138 consecutive V/Q patients were compared with that of 149 consecutive CTA patients during equivalent 6-month intervals before and after the introduction of CTA. Information on risk factors, signs and symptoms, all diagnostic test results, and the relationships between the test results and ultimate physician management were collected and analyzed. V/Q results predicted physician management in all patients with high probability scans and 91% with normal to low probability scans. There were 35 patients with indeterminate V/Q scans--43% of these patients were managed without any other diagnostic test. CTA results predicted management in all patients with positive studies and 99% of patients with negative studies. In contrast to the V/Q cohort, only seven CTA studies were inconclusive--additional diagnostic tests determined management in all but one case. Compared with V/Q, CTA has fewer indeterminate results, is more directly reflective of management, and reduces the number of patients managed with inconclusive data.

Spiral Computed Tomography for Acute Pulmonary Embolism

“…In reality, however, this test is infrequently performed. 21,22 The morbidity and mortality rates for this invasive test are reported to range from 3.5% to 6% and 0.2% to 0.5%, respectively. [23][24][25] Use of nuclear medicine imaging, once the first imaging study for suspected PE, is in decline 26,27 because of the high percentage of indeterminate studies (73% of all performed 28 ) and poor interobserver correlation.…”

Multidetector CT pulmonary angiography features of pulmonary embolus

“…The incidence of indeterminate studies is reported to be between 0.5 and 10.8% with a mean of 6.4%. 5,[24][25][26][27][28][29][30][31][32] The two most common causes are respiratory motion and poor contrast enhancement. 24…”

Spiral computed tomography is the first-line chest imaging test for acute pulmonary embolism: no

“…Although still the most commonly used diagnostic test, a lung scan is non‐diagnostic in most patients and requires additional testing. The current ‘gold standard’, pulmonary angiography, is expensive, invasive, technically demanding to perform and, as a consequence, infrequently used [2]. Given the persistent difficulties in the diagnosis of pulmonary embolism new diagnostic tests are welcomed with enthusiasm.…”