thought objective: To compare digital to conventional film-screen pulmonary angiography for the diagnosis of acute pulmonary embolism (PE) in a clinical population.

Design: Retrospective review of patient data, ventilation/perfusion (V/Q) lung scintigraphy reports, and pulmonary angiographic reports.

Setting: University hospital, division of interventional radiology.

Patients and methods: Patient data from 307 film-screen and 266 digital angiograms were analyzed for demographics, V/Q lung scintigraphy findings, and pulmonary artery presss to define patient populations. The interpretations of film-screen pulmonary angiography were then compared with digital angiography interpretations for the entire clump of interventional radiologists as well as the pair interventionists who practiced throughout the thought interval to determine any difference in rates of diagnosis of acute PE between the pair techniques.

Results: There was no significant difference between the patient populations studied at film-screen or digital techniques for the data reviewed. Digital angiography utilized significantly more contrast material (digital, 173 mL; film-screen, 145 mL; p < 001) and a greater number of angiographic views (digital, 36 views by patient; film-screen, 3.4 views by patient; p = 0.04) when compared with film-screen angiography. There was no difference between the sum of two units techniques in the rates of diagnosis of acute PE for individual radiologists or overall.

Conclusions: Digital and film-screen pulmonary angiography posses equivalent diagnostic capabilities for acute PE as used in a clinical setting.

first note of the scale words: comparative studies; digital subtraction angiography; pulmonary angiography; pulmonary embolism

Abbreviations: PE = pulmonary embolism; PIOPED = Prospective Investigation of Pulmonary Embolism Diagnosis; V/Q = ventilation/perfusion

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Pulmonary angiography is regarded as the imaging standard of respect for the diagnosis of pulmonary embolism (PE) and aids as the basis by which other imaging studies, principally notably helical CT scanning, are evaluated. (1-4) The secondary version of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) has lately begun patient recruitment with the specific aim of determining the sensitivity, specificity, and positive and negative predictive values of contrast-enhanced helical CT scanning for the diagnosis of acute PE (PIOPED II cogitation protocol). The study uses a composite respect test for venous embolic disease, including digital pulmonary angiography. The purport of PIOPED II is to determine the bulk to which helical CT scanning can subserve as a minimally invasive example for PE, thereby eliminating or reducing the ne for pulmonary angiography.

Although it aids as the "gold standard" for the diagnosis of PE there are clinical pertain tos with pulmonary angiography. Even although it is quite safe, pulmonary angiography is still an invasive action and can be time-consuming for as well-as; not only-but also; not only-but; not alone-but the patient and interventional radiologist, particularly when performed using standard film-screen techniques. (5) Interobserver variability has been reported to be quite high, particularly for subsegmental emboli. (6-8) Stein et al (9) have reviewed pulmonary angiography data from the first PIOPED trial and construct conventional film-screen pulmonary angiography to be imprecise for the diagnosis of PE that is limited to subsegmental arteries. CT scanning is also les accurate for the detection of subsegmental thrombus, and angiography is repeatedly used to finalize the diagnosis of PE

Despite these disquiets with even conventional film-screen angiography, digital pulmonary angiography is widely applied for the diagnosis of PE Indeed, digital techniques have become in such a manner dominant in the marketplace that chiefly major equipment manufacturers now furnish film-screen capabilities only as an option. This has, unfortunately, been based forward ease of imaging and the inferred clinical equivalency of the sum of two units techniques, without substantial published data. sum of two units controlled comparative series (10,11) published in 1998 reported that digital was at least equivalent to film-screen angiography. However, these studies were performed with limited film-screen views of a single lung in small patient series. Although this certainly allowed side-to-side image comparison, it did not permit the comparison of clinical be the effects for the two techniques. For example, independent interpreters were barely provided with photographed digital images for comparison. Digital angiography is clinically interpreted with the aid of a workstation, which affords essential image manipulation.

In our allow institution, pulmonary angiography has been performed solely by way of digital techniques since 1994. Prior to that time, pulmonary angiography was performed using exclusively conventional film-screen techniques. In addition, helical CT scanning was not utilized for the diagnosis of acute PE in our institution until 1997 This provides a population of patients that allows retrospective comparison of the couple angiographic techniques. Given the paucity of clinical data regarding digital v film-screen pulmonary angiographic techniques and the important part that digital pulmonary angiography has assumed as the imaging standard of allusion for the diagnosis of PE especially in light of the PIOPED II findings, we believe there is a ne for the publication of data comparing the sum of two units techniques as utilized in a clinical setting. With this in mind, we assessed our avow experience with digital pulmonary angiography for acute PE since conversion from the conventional film-screen approach to determine any significant differences in diagnostic stretchs between the two techniques as applied to a large clinical population.

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