Improved visualization of malpositioned middle ear prostheses using photon-counting detector CT: a cadaver study.

Abstract

Background: Evaluation of middle ear prostheses requires high-resolution imaging to assess position and structural integrity.

Purpose: To assess the diagnostic performance of photon-counting-detector (PCD)-CT for middle ear prosthesis imaging in cadaveric specimens.

Materials and methods: Nine different middle ear prostheses were implanted in 5 fresh-frozen whole-head specimens, both in correct anatomic position and displaced to mimic malposition. Specimens were scanned on PCD-CT (NAEOTOM Alpha, Siemens) and energy-integrating-detector (EID)-CT (SOMATOM Force, Siemens), reconstructed at 0.2 mm and 0.4 mm, respectively. Eighteen cases (9 prostheses, 2 positions) per scanner were evaluated by 2 neuroradiologists (36 readings), blinded to scanner and position, who scored prosthesis position, reader confidence, and overall image quality. Agreement with the reference standard and between readers was compared.

Results: PCD-CT showed higher diagnostic confidence compared with EID-CT, while accuracy and inter-reader agreement did not demonstrate significant differences between scanners. Correct readings, PCD-CT versus EID-CT: lateral contact, 31/36 (86.1%; 95% CI, 58.3-94.4) vs 29/36 (80.6%; 95% CI, 55.6-91.7), P = .500; medial contact, 30/36 (83.3%; 95% CI, 55.6-94.4) vs 26/36 (72.2%; 95% CI, 50.0-83.3), P = .250. PCD-CT identified all cases of complete contact loss (score 3), while EID-CT missed 1 reading per contact. Inter-reader agreement may be higher with PCD-CT vs EID-CT (lateral: κ_w: 0.804 [95% CI, 0.578-0.941] vs 0.571 [95% CI, 0.302-0.778], P = .250; medial: 0.684 [95% CI, 0.191-0.934] vs 0.481 [95% CI, 0.024-0.835], P = .250). Reader confidence was significantly higher with PCD-CT; mean paired differences for Readers 1 and 2 were 9.4 (95% CI, 1.8-17.1; Holm-adjusted P = .019) and 23.1 points (95% CI, 13.4-32.7; P < .001) for lateral contact, and 16.4 (95% CI, 10.0-22.8; P < .001) and 17.8 points (95% CI, 6.8-28.8; P = .007) for medial contact. Readers preferred PCD-CT image quality in 16/18 (88.9%; 95% CI, 65.3-98.6) and 17/18 cases (94.4%; 95% CI, 72.7-99.9), respectively.

Conclusion: PCD-CT was associated with significantly higher reader confidence and preferred image quality, without significant differences in diagnostic accuracy or inter-reader agreement. These findings suggest that PCD-CT is a promising modality for postoperative middle ear evaluations and warrants further investigations.