MRI is preferable to CT when imaging pregnant patients with appendicitis
For pregnant patients clinically suspected of having acute appendicitis (AA), use of MRI yields favorable combinations of negative laparotomy rate (NLR) and perforation rate compared with previously reported values, according to a study in the March issue of Radiology.
Ivan Pedrosa, MD, from the department of radiology at Beth Israel Deaconess Medical Center, Harvard Medical School in Boston, and colleagues collected the data of 148 consecutive pregnant patients (mean age, 29 years; age range, 15-42 years; mean gestational age, 20 weeks), who were clinically suspected of having AA and examined with MRI between March 2002 and August 2007.
The researchers performed ultrasonography on 148 patients, before performing an MRI. They recorded clinical and laboratory data and the findings of the initial ultrasonography and MR image interpretations, and calculated the NLR and perforation rate.
Pedrosa and colleagues found that 10 percent of patients had AA, and perforation occurred in 21 percent of them. The ultrasonography results were positive for AA in 36 percent of patients with proved AA. MR results were positive in all 14 patients with AA.
According to the investigators, the MRI results were negative in 125 of the 134 patients without AA; there were nine false-positive cases (two positive, seven inconclusive). Among the patients without AA, the normal appendix could be visualized on ultrasonography images in less than 2 percent of cases and on MR images in 87 percent of cases.
The authors also reported that 18 percent of patients underwent surgical exploration, and eight of them had negative laparotomy results, yielding an NLR of 30 percent and a PR of 21 of patients. Only 3 percent of patients underwent CT.
Based on the findings, Pedrosa and colleagues concluded that "the radiation exposure associated with CT examination can be avoided in most cases."
Ivan Pedrosa, MD, from the department of radiology at Beth Israel Deaconess Medical Center, Harvard Medical School in Boston, and colleagues collected the data of 148 consecutive pregnant patients (mean age, 29 years; age range, 15-42 years; mean gestational age, 20 weeks), who were clinically suspected of having AA and examined with MRI between March 2002 and August 2007.
The researchers performed ultrasonography on 148 patients, before performing an MRI. They recorded clinical and laboratory data and the findings of the initial ultrasonography and MR image interpretations, and calculated the NLR and perforation rate.
Pedrosa and colleagues found that 10 percent of patients had AA, and perforation occurred in 21 percent of them. The ultrasonography results were positive for AA in 36 percent of patients with proved AA. MR results were positive in all 14 patients with AA.
According to the investigators, the MRI results were negative in 125 of the 134 patients without AA; there were nine false-positive cases (two positive, seven inconclusive). Among the patients without AA, the normal appendix could be visualized on ultrasonography images in less than 2 percent of cases and on MR images in 87 percent of cases.
The authors also reported that 18 percent of patients underwent surgical exploration, and eight of them had negative laparotomy results, yielding an NLR of 30 percent and a PR of 21 of patients. Only 3 percent of patients underwent CT.
Based on the findings, Pedrosa and colleagues concluded that "the radiation exposure associated with CT examination can be avoided in most cases."