MDCT of abdominal wall hernias: is there a role for valsalva's maneuver?

OBJECTIVE

Our objective was to evaluate the role of Valsalva's maneuver during MDCT for the diagnosis and characterization of abdominal wall hernias.

SUBJECTS AND METHODS

From September 2002 to May 2003, 100 consecutive patients (37 men and 63 women; mean age, 53 years) with suspected anterior abdominal wall hernias underwent 4-, 8-, or 16-MDCT with and without Valsalva's maneuver. Patients received both oral and IV contrast material. On a workstation, three independent reviewers evaluated each scan obtained during rest and during Valsalva's maneuver for the following parameters: anteroposterior (AP) diameter of the abdomen; presence, location, and contents of the hernia; and transverse diameter of the fascial defect. The scans were compared to assess for changes in hernia size and contents and to determine whether the hernia would have been overlooked without Valsalva's maneuver. Fisher's exact test, the McNemar test, and Cohen's kappa coefficient were used to assess for significant differences.

RESULTS

The three reviewers identified a mean of 72 abdominal wall hernias (72%). The reviewers agreed (kappa = 0.723) with respect to the presence of a hernia. AP diameters increased an average of 1.33 cm during Valsalva's maneuver (p < 0.001). The transverse diameter of the fascial defect increased an average of 0.66 cm and the AP diameter of the hernia sac increased an average of 0.79 cm during Valsalva's maneuver (p < 0.001). Fifty percent of the hernias became more apparent with Valsalva's maneuver. Ten percent of the hernias could be detected only on the scan obtained during Valsalva's maneuver. Conversely, in no patients was the hernia detected only on the rest scan.

CONCLUSION

As opposed to scans obtained at rest, scans obtained during Valsalva's maneuver aid in the detection and characterization of suspected abdominal wall hernias. A single scan obtained during Valsalva's maneuver is sufficient to detect 100% of anterior abdominal wall hernias identified on CT.