Acquisition of CT both with and without contrast does not generally add diagnostic value. Although available evidence and experience generally supports the appropriateness of CT with IV contrast over that of noncontrast CT for evaluation of intra-abdominal organs and pathology [12,14,15], the use of noncontrast CT may be of value in some circumstances. US Abdomen US has many positive attributes and is a useful tool for detecting and diagnosing potential intra-abdominal masses [4-6,16-19]. In a retrospective study including 104 patients with palpable masses referred for US evaluation, 69 had a correlative mass and US correctly identified the organ of origin in 88% of patients [17]. The 3 cases where the organ of origin was not positively identified were all masses arising in the pelvis (endometriosis, uterine fibroids, and ovarian tumor), which were later defined on CT. Despite the failure in these cases, the positive predictive value was 99% and negative predictive value 97% for identifying or excluding a mass. The one false- negative case was a patient with palpable mass on examination who had a negative US but subsequently positive CT demonstrating transverse colon cancer. The accuracy for identifying the organ of origin ranges from 88% to 91%, and 77% to 81% for correctly suggesting the underlying pathology [16,17,20,21]. Although highly accurate, US visibility of the abdominal cavity may be limited because of bowel gas and body habitus. On the other hand, US has the benefit of real-time imaging. This can be very advantageous in the setting of palpable abnormality, providing additional information, such as tenderness, direct correlation, and dynamic changes like Valsalva maneuvers, when assessing for hernias. Studies have suggested that portable US units may improve diagnostic accuracy for detecting organomegaly [22] and may help to determine the need for additional diagnostic testing with a sensitivity of 91% and specificity of 83% [23].
Palpable Abdominal Mass Suspected Neoplasm. Acquisition of CT both with and without contrast does not generally add diagnostic value. Although available evidence and experience generally supports the appropriateness of CT with IV contrast over that of noncontrast CT for evaluation of intra-abdominal organs and pathology [12,14,15], the use of noncontrast CT may be of value in some circumstances. US Abdomen US has many positive attributes and is a useful tool for detecting and diagnosing potential intra-abdominal masses [4-6,16-19]. In a retrospective study including 104 patients with palpable masses referred for US evaluation, 69 had a correlative mass and US correctly identified the organ of origin in 88% of patients [17]. The 3 cases where the organ of origin was not positively identified were all masses arising in the pelvis (endometriosis, uterine fibroids, and ovarian tumor), which were later defined on CT. Despite the failure in these cases, the positive predictive value was 99% and negative predictive value 97% for identifying or excluding a mass. The one false- negative case was a patient with palpable mass on examination who had a negative US but subsequently positive CT demonstrating transverse colon cancer. The accuracy for identifying the organ of origin ranges from 88% to 91%, and 77% to 81% for correctly suggesting the underlying pathology [16,17,20,21]. Although highly accurate, US visibility of the abdominal cavity may be limited because of bowel gas and body habitus. On the other hand, US has the benefit of real-time imaging. This can be very advantageous in the setting of palpable abnormality, providing additional information, such as tenderness, direct correlation, and dynamic changes like Valsalva maneuvers, when assessing for hernias. Studies have suggested that portable US units may improve diagnostic accuracy for detecting organomegaly [22] and may help to determine the need for additional diagnostic testing with a sensitivity of 91% and specificity of 83% [23].