CTangiografi

CTangiografi, or CT angiography (CTA), is a medical imaging modality that uses computed tomography to visualize blood vessels after intravenous iodinated contrast. By rapid acquisition and three-dimensional reconstruction, CTA reveals vessel caliber, stenosis, aneurysms, dissections and occlusions. It is less invasive than catheter angiography and can cover large vascular territories in a single exam. Modern CTA uses multi-detector or dual-source CT scanners and may employ ECG gating for arterial-phase visualization.

During the exam, iodinated contrast is injected, usually via a vein in the arm, followed by a saline flush. A rapid acquisition protocol synchronized with the contrast bolus ensures imaging during the arterial phase. The scanner gathers data quickly, producing thin slices that can be reformatted into 3D models. The study is typically completed in a few minutes; breath-holding may be needed for chest or abdomen imaging.

Indications include evaluation of aneurysms and dissections (aorta, carotids), pulmonary embolism, renal or mesenteric artery occlusion, and acute stroke or chest pain. Coronary CTA assesses coronary artery disease in selected patients and can aid in planning interventions.

Safety and limitations: Risks include allergic reaction to iodinated contrast and contrast-induced nephropathy, especially in patients with kidney disease. Radiation exposure is a consideration, though dose optimization reduces it. Artifacts from motion, metal implants, or high heart rate can impair image quality, and CTA does not directly measure vessel function.

History and notes: CTA has evolved since the 1990s with advances in detectors and post-processing, expanding the use of noninvasive vascular imaging.