False-Positive Cholesteatomas on Non-Echoplanar Diffusion-Weighted Magnetic Resonance Imaging

Abstract

Objectives: To investigate false-positive findings on nonechoplanar (non-EPI) diffusion-weighted magnetic resonance imaging (DWI) in patients under surveillance post-cholesteatoma surgery. Study Design, Setting, Subjects, and Methods: A retrospective review was performed on patients diagnosed with cholesteatoma who underwent surgical resection and were then followed by serial non-EPI DWI using half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence. All patients had at least two annual follow-up imaging studies. Results: False-positive findings were identified in four patients. The size of the suspected lesions was 4 to 12 mm. Otoendoscopy was used during all primary cases and Argon laser was used in one case. In all cases, the entire cholesteatoma was removed, and no residual disease was detected at the end of the procedures. One patient underwent revision surgery but only cartilage graft was found in the area of concern. All patients had stable or resolved hyperintense areas in the subsequent HASTE sequences. Conclusion: False positive findings can occur with non-EPI DWI MRI and patients need to be counseled accordingly before revision surgery. Decreasing intensity and dimension of a suspected lesion and a positive finding in an area other than the location of the initial cholesteatoma may favor a false positive. If a false positive finding is suspected when the surgeon is confident of complete resection of the cholesteatoma, an MRI can be repeated in 6 to 12 months to assess changes in the dimension and intensity of the area of concern. Cartilage grafts may cause restricted diffusion on DWI sequences.

Non-EPI versus Multishot EPI DWI in Cholesteatoma Detection: Correlation with Operative Findings

“…Nevertheless, false-positives have been reported, related to abscess, wax/debris, and encephaloceles. 25 False-negatives, too, occur, particularly in small (,3-5 mm) lesions. [26][27][28] Horn et al, 27 for example, concluded that non-EPI DWI does not eliminate the need for second-look surgery due to the rate of false-negative examinations.…”

Combining Thin-Section Coronal and Axial Diffusion Weighted Imaging: Good Practice in Middle Ear Cholesteatoma Neuroimaging

“…However, despite the good resolution and the lower incidence of interface artifacts in thin-section coronal fast spin-echo–based non-EPI techniques, few cases of false negatives and false positives have still been observed. While false negatives are mainly due to very small lesion size, false positives can be due to several different condition that could enhance the presence of MRI artifacts (i.e., presence of prosthetic materials or metallic dental implants, recent surgery, admixed otomastoiditis with areas of abscessualisation) ( 1 , 23 , 24 ). To overcome possible pitfalls and implement the interpretation of indeterminate single-plan DWI, additional axial DWI can be a worthwhile information support.…”

Diffusion-weighted magnetic resonance imaging for diagnosis of post-operative paediatric cholesteatoma

“…One study, specifically focusing on false positives in the adult population, reported that in three of the four false positive cases, areas of high avidity disappeared on subsequent imaging. 17 They reported false positives to be related to cartilage grafts. 17 Within our study, one of the false positives was reported as 'possible cholesteatoma' and did not have symptoms at the time of diffusion-weighted MRI; this patient could possibly have been followed up with subsequent imaging.…”

“…17 They reported false positives to be related to cartilage grafts. 17 Within our study, one of the false positives was reported as 'possible cholesteatoma' and did not have symptoms at the time of diffusion-weighted MRI; this patient could possibly have been followed up with subsequent imaging. However, the other four patients were reported as 'probable cholesteatoma' or 'definite cholesteatoma', and three of the four had symptoms, making any decision not to operate challenging.…”