Abstract W P163: Could CT Angiogram be the Next Screening Test for Carotid Disease? Ultralow Radiation for Neck CT Angiography
Introduction: CTA is a high resolution technique, used to confirm carotid and vertebral artery stenosis suspected on carotid ultrasound or MRA. However, this technique rightfully so has not been used as a screening technique given concerns regarding radiation dose, particularly on young patients and repeat examinations, with special consideration of anatomic proximity to the thyroid, a radiosensitive organ. Our objective is to significantly reduce the effective radiation dose of this exam, without reducing diagnostic accuracy.
Methodology: A new reduced radiation dose scanning protocol for neck CTA (100 Kv, 140 Ma, pitch 0.5, rot time 0.5 sec) was developed at our institution and applied on 10 patients who underwent the exam with indication of vascular disease. The exams were reviewed by 2 staff radiologists who assessed image quality and diagnostic accuracy, both on standard thin slice (0.625 mm) images, orthogonal views and dedicated high resolution individual vessel reconstructions. Total radiation doses were obtained, and compared against the standard of care protocol (120 Kv, 235 Ma, pitch 0.5, rot time 0.5 sec).
Results: Compared to standard of care imaging protocol we achieved a 62% reduction of radiation dose, from a CTDI of 42 mGy to 16 mGy and an estimated dose for thyroid gland from 14.2 mSv to 5.1 mSv. All 10 exams were considered of diagnostic quality. Image resolution for neck soft tissues was not affected.
Conclusion: The number of neck CTA exams are rising in the last decade. Efforts must be made in order to keep radiation doses to the minimum possible without compromising image quality. This new low dose protocol enables full diagnostic capabilities of vascular disease with significant dose reduction. Although this dose is not low enough for a viable screening test, there is potential for further reduction, which can be researched and applied in future studies.
Author Disclosures: D.A. Lira: None. R.G. Gonzalez: None. M.K. Kalra: None. S. Singh: None. J.M. Romero: None.
- © 2014 by American Heart Association, Inc.