CT angiopulmonography - an X-ray contrast study of the pulmonary arteries using computed tomography ( CT angiography of the pulmonary arteries). The main goal of the method is the diagnosis of pulmonary embolism [1] . CT angiopulmonography is the preferred method of medical imaging due to its low invasiveness (only catheterization of the vein is necessary for the study).
Content
General information
Modern multi-detector computed tomographs (MDCTs) provide the optimal resolution and image quality for this study [2] . For informative research, the thickness of the scanned layer of 0.625 mm - 2 mm is sufficient. 50-100 ml of contrast medium is administered bolus at a rate of 4 ml / s. A contrast enhancement sensor is located on the pulmonary arteries, which are located just below the bifurcation of the trachea . The study is conducted at the peak of contrast enhancement of the pulmonary arteries.
On MDCT scanning is performed for 5 seconds or less, in general, a visit to a patient with a pre-installed catheter takes about 5 minutes.
Normally, CT angiopulmonography demonstrates uniform filling of the pulmonary arteries with a contrast agent. Obstruction of blood flow in the lumen of the vessel is visualized in the form of a “dark” non-contrasting area (filling defect). Ideally, at the time of examination, the aorta should not be filled with a contrast agent, which eliminates artifacts that can simulate filling defects.
Diagnostic value
CT angiopulmonography began to be used in the 1990s as an alternative to radionuclide ventilation-perfusion scanning and demonstrated high sensitivity and specificity for pulmonary embolism [1] .
CT angiopulmonography is usually used in the case of a clinical picture of pulmonary embolism. If the probability of pulmonary embolism is low, a blood test is performed for . With a negative result and low risk of pulmonary embolism, CT angiopulmonography is not prescribed. Most patients undergo a chest x-ray before a CT scan is prescribed [1] .
In connection with the previously doubts about the informativeness of the method in relation to small emboli, in 2007 the results of CT angiopulmonography and ventilation perfusion scanning were compared. In the study, CT angiopulmonography showed higher sensitivity [3] .
Contraindications
CT angiopulmonography is usually contraindicated during pregnancy, due to the effect of ionizing radiation on the fetus [4] .
CT angiopulmonography is contraindicated in case of known or suspected allergy to a contrast drug , as well as in case of renal failure (since the contrast drug has nephrotoxicity ) [3] .
Notes
- ↑ 1 2 3 Fedullo PF, Tapson VF Clinical practice. The evaluation of suspected pulmonary embolism (Eng.) // N. Engl. J. Med. : journal. - 2003. - Vol. 349 , no. 13 . - P. 1247-1256 . - DOI : 10.1056 / NEJMcp035442 . - PMID 14507950 .
- ↑ Schoepf UJ, Goldhaber SZ, Costello P. Spiral computed tomography for acute pulmonary embolism (English) // Circulation : journal. - Lippincott Williams & Wilkins 2004. - Vol. 109 , no. 18 . - P. 2160-2167 . - DOI : 10.1161 / 01.CIR.0000128813.04325.08 . - PMID 15136509 .
- ↑ 1 2 Anderson DR, Kahn SR, Rodger MA et al. Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism (English) // JAMA: journal. - 2007. - Vol. 298 , no. 23 . - P. 2743-2753 . - DOI : 10.1001 / jama.298.23.2743 . - PMID 18165667 .
- ↑ Scarsbrook AF, Gleeson FV Investigating suspected pulmonary embolism in pregnancy (Eng.) // BMJ : journal. - 2007. - Vol. 334 , no. 7590 . - P. 418-419 . - DOI : 10.1136 / bmj.39071.617257.80 . - PMID 17322258 .