Objective: To assess the efficacy of color mapped fusion images (CMFIs) in preoperatively evaluating the anatomic location of cholesteatomas and determining whether a patient is indicated for transcanal endoscopic ear surgery.
Study design: Prospective case study.
Setting: A single university hospital.
Patients: Ninety-two patients scheduled for middle ear cholesteatoma surgery.
Intervention: Imaging analysis was first performed using echo planar diffusion-weighted imaging (EPI) for the first patient group with mixed results. Imaging analysis was then performed using 1-mm thin-slice non-EPI combined with magnetic resonance cisternography in a second group. The resulting image was then processed using color mapping to create a CMFI that enhanced cholesteatoma visualization. A second non-EPI was also performed on the third group, incorporating a T1-weighted image (T1WI) to reduce false-positives.
Main outcome measure(s): Preoperative findings from EPI, non-EPI/CMFIs, and non-EPI/T1WI-enhanced CMFIs were compared with intraoperative findings. The positive predictive value and negative predictive value were also evaluated for each group.
Results: Both the positive predictive value and negative predictive value obtained from the CMFIs were high in all areas of the middle ear, and CMFI facilitated accurate detection of the anatomic location of cholesteatomas of 3 mm or larger. The incidence of false-positives was further reduced in the final 18 patients by performing T1WI to distinguish between cholesteatomas and cholesterin granulomas.
Conclusion: CMFI combined with T1WI is a reliable diagnostic modality for evaluating the anatomic location of cholesteatomas 3 mm or larger and determining whether transcanal endoscopic ear surgery is indicated for treatment in such cases.