When compared to CTA, a study reported that the low-dose noncontrast CT exhibited similar accuracy and reproducibility of measurements in AAA [16]. CTA Abdomen and Pelvis With IV Contrast Contrast-enhanced CT scans are known to be more precise when compared to US, with near 100% sensitivity and specificity, and are more reliable than US at determining size and extent and demonstrating adjacent structures, and are not degraded by bowel gas or obesity. Although contrast-enhanced CTA is an effective diagnostic tool, it has not been generally accepted as a screening tool due to its use of IV contrast [12,13]. CTA imaging of AAA is now well-established and is a popular imaging choice for diagnostic and presurgical/intervention study and sometimes surveillance of AAA, with particular strength in demonstrating the size, extent, and other characteristics of an aneurysm and associated aortic branch disease. The difference between US and CTA measurements of AAA were reported, with general accusation that US underestimates AAA diameter and that CT demonstrates a closer reflection of the actual diameter, with parallel debate over the ideal measuring method without complete consensus [17,18]. Recent updates from the 2018 The Society for Vascular Surgery guidelines for the care of AAA patient now recommends using the outer wall to outer wall for measurement of the maximum aneurysm diameter [6], moving away from the inner wall to inner wall measurements. CTA Abdomen and Pelvis Without and With IV Contrast Noncontrast CT scans were not commonly used as a primary screening tool for AAA in the past, but recent studies have explored their potential as an alternative method [13,19]. One such study of 533 patients reported a higher sensitivity (83%-89% versus 57%-70%) with high specificity over 98% when compared to US [12].
Screening for Abdominal Aortic Aneurysm. When compared to CTA, a study reported that the low-dose noncontrast CT exhibited similar accuracy and reproducibility of measurements in AAA [16]. CTA Abdomen and Pelvis With IV Contrast Contrast-enhanced CT scans are known to be more precise when compared to US, with near 100% sensitivity and specificity, and are more reliable than US at determining size and extent and demonstrating adjacent structures, and are not degraded by bowel gas or obesity. Although contrast-enhanced CTA is an effective diagnostic tool, it has not been generally accepted as a screening tool due to its use of IV contrast [12,13]. CTA imaging of AAA is now well-established and is a popular imaging choice for diagnostic and presurgical/intervention study and sometimes surveillance of AAA, with particular strength in demonstrating the size, extent, and other characteristics of an aneurysm and associated aortic branch disease. The difference between US and CTA measurements of AAA were reported, with general accusation that US underestimates AAA diameter and that CT demonstrates a closer reflection of the actual diameter, with parallel debate over the ideal measuring method without complete consensus [17,18]. Recent updates from the 2018 The Society for Vascular Surgery guidelines for the care of AAA patient now recommends using the outer wall to outer wall for measurement of the maximum aneurysm diameter [6], moving away from the inner wall to inner wall measurements. CTA Abdomen and Pelvis Without and With IV Contrast Noncontrast CT scans were not commonly used as a primary screening tool for AAA in the past, but recent studies have explored their potential as an alternative method [13,19]. One such study of 533 patients reported a higher sensitivity (83%-89% versus 57%-70%) with high specificity over 98% when compared to US [12].