Rising utilization rates of preoperative CT over the past 10 years, as well as advances in CT technology, corresponded to the decrease in the negative appendectomy rate for women 45 years of age and younger, based on the results of a recent retrospective study published in the February edition of Radiology.
Courtney Coursey, MD, Emory University in Atlanta, and colleagues found that the shift from single-detector CT to multidetector CT usage coincided with a noted reduction in false-positive appendicitis diagnoses within a cohort of women between the ages of 18-45 throughout the course of their 10-year study.
In addition, the researchers noted that due to advances in CT technology, negative appendectomy rates among the women dropped from 42.9 percent in 1998 to 7.1 percent in 2007.
Coursey, who co-wrote the study while completing a radiology fellowship at Duke University Medical Center in Durham, N.C., and colleagues, utilized a surgical database from an urban university hospital and collected medical information on 925 urgent appendectomy patients admitted between January 1998 and September 2007.
They reviewed CT, pathology and surgery reports to determine a patient population for their study. Of the 925 patients selected, 526 were male and 399 were female, with an age range of 18-95 years.
An acutely inflamed appendix appears thick-walled and adjacent inflammatory changes are often visible by way of a multidetector CT scan, wrote the authors, who noted a significant rise in the use of preoperative CT during the course of the 10 years reviewed, from an 18.5 percent utilization rate in 1998 to 93.2 percent in 2007.
Within the patient-population, a correlation between less false-positive appendicitis diagnoses and lower appendectomy rates were found only in the subgroup study of women of reproductive age. The researchers wrote that this may be due to gynecologic pathology historically confounding appendicitis diagnosis, citing past rates of unnecessary appendectomies to be as high as 40 percent in women.
"CT is a very helpful test for women 45 years and younger based on the overall trends we observed during the 10-year period," Coursey said.
Despite the findings of this subgroup of patients within the study, Coursey and colleagues did not discover a lower negative appendectomy rate in women older than 45, or in men, regardless of age, through the use of preoperative CT, which the researchers attributed to a very low negative appendectomy rate in these subgroups.
"Although it's a terrific test, CT and our interpretation of CT images are not 100 percent perfect," the authors wrote. "Therefore, it may be difficult to improve significantly upon diagnosis in groups with an already low negative appendectomy rate."