A novel diagnostic aid for intra-abdominal adhesion detection in cine-MRI: pilot study and initial diagnostic impressions

Abstract

Objective: A non-invasive diagnostic technique for abdominal adhesions is not currently available. Capture of abdominal motion due to respiration in cine-MRI has shown promise, but is difficult to interpret. This article explores the value of a complimentary diagnostic aid to facilitate the non-invasive detection of abdominal adhesions using cine-MRI.

Method: An image processing technique was developed to quantify the amount of sliding that occurs between the organs of the abdomen and the abdominal wall in sagittal cine-MRI slices. The technique produces a "sheargram" which depicts the amount of sliding which has occurred over 1-3 respiratory cycles. A retrospective cohort of 52 patients, scanned for suspected adhesions, made 281 cine-MRI sagittal slices available for processing. The resulting sheargrams were reported by two operators and compared with expert clinical judgment of the cine-MRI scans.

Results: The sheargram matched clinical judgment in 84% of all sagittal slices and 93-96% of positive adhesions were identified on the sheargram. The sheargram displayed a slight skew towards sensitivity over specificity, with a high positive adhesion detection rate but at the expense of false positives.

Conclusion: Good correlation between sheargram and absence/presence of inferred adhesions indicates quantification of sliding motion has potential to aid adhesion detection in cine-MRI.

Advances in knowledge: This is the first attempt to clinically evaluate a novel image processing technique quantifying the sliding motion of the abdominal contents against the abdominal wall. The results of this pilot study reveal its potential as a diagnostic aid for detection of abdominal adhesions.

Figure 1.

Two examples where the sheargram correctly correlated with positively inferred adhesions (a and b) and two healthy sheargrams which correctly correlated with an absence of adhesions (c and d). White arrows and lines annotate location and extent of each adhesion.

Figure 2.

Number of sheargrams which agree/disagree with clinical decision on adhesions in the cine-MRI (broad classification).

Figure 3.

Correlation between the sheargram and clinically inferred adhesions on the cine-MRI for each of the two reporters represented as pie charts and 2 × 2 contingency tables. The numbers on the charts are the number of sagittal slices (total sagittal slices = 140).

Figure 4.

The 12 changes made between the original cine-MRI report and the radiologist's clinical decision in the pilot study.

Figure 5.

The two false negative sheargram examples from the pilot study.