Diagnostic accuracy of computed tomography findings for patients undergoing salvage total laryngectomy

CT of the Larynx: Is an Additional High-Resolution Acquisition Necessary for Diagnostic Accuracy?

BACKGROUND AND PURPOSE

Diagnostic CT of the larynx is historically performed with a protocol that combines a standard neck CT with dedicated imaging through the larynx. Multichannel CT scanners, however, allow high-resolution reformatted images of the larynx to be created directly from the initial neck acquisition data. The purpose of this study was to determine whether reformatted laryngeal images derived from a standard neck CT acquisition provide information comparable with that of separate dedicated high-resolution laryngeal images.

MATERIALS AND METHODS

The CT protocol for suspected laryngeal masses at our institution consists of a standard neck acquisition followed by a second acquisition focused on the larynx. We enrolled 200 patients who had undergone this protocol for a suspected laryngeal mass. Two head and neck radiologists independently reviewed each of the 200 scans twice. In one session, the entire scan was available, while in the other session, only images derived from the standard neck acquisition were available. The main outcome variable was the frequency of discrepant tumor staging between the interpretation sessions. No pathologic reference standard was used.

RESULTS

Radiologist A had discrepant staging in 45 of the 200 scans (23%; 95% CI, 17%-29%). Radiologist B had discrepant staging in 42 of the 200 scans (21%; 95% CI, 16%-27%). Fifty-three of the 87 discrepancies (61%) reflected improper downstaging of the laryngeal tumor on standard images alone, while the other 34 (39%) had improper upstaging on standard images alone.

CONCLUSIONS

Reformatted images from our institution's standard neck CT acquisition were less accurate than dedicated images of the larynx for analysis of laryngeal tumor extension. Focused images of the larynx were needed to optimize interpretation.

Comparison of diagnostic performance between CT and MRI for detection of cartilage invasion for primary tumor staging in patients with laryngo-hypopharyngeal cancer: a systematic review and meta-analysis

OBJECTIVE

To compare the diagnostic performance of contrast-enhanced CT with that of MRI in the detection of cartilage invasion in patients with laryngo-hypopharyngeal cancer.

METHODS

A systematic literature search in the Ovid-MEDLINE and EMBASE databases was performed for studies reporting diagnostic accuracy of CT and/or MRI in detecting cartilage invasion from laryngo-hypopharyngeal cancer between 2000 and 2018. The pooled sensitivity and specificity, and their 95% confidence intervals were calculated for CT and MRI using bivariate random effects modeling. Subgroup and meta-regression analyses were performed. Indirect comparison was also performed by univariable meta-regression.

RESULT

Fourteen articles including 776 patients were included in the systematic review and meta-analysis: eight for CT, and six for MRI. CT and MRI showed pooled sensitivities of 66% (95% CI, 49-80%) and 88% (95% CI, 79-93%), and pooled specificities of 90% (95% CI, 82-94%) and 81% (95% CI, 76-84%), respectively. MRI showed significantly higher sensitivity than CT (p = 0.02). The specificities showed no statistically significant difference between CT and MRI (p = 0.39). The CT studies showed heterogeneity and a threshold effect, while MRI showed neither heterogeneity nor threshold effect. In the meta-regression analysis for CT, the type of cartilage analyzed (thyroid only vs. thyroid/cricoid/arytenoid, p < 0.001) was a significant factor influencing the heterogeneity in the diagnostic performance of the CT studies.

CONCLUSIONS

In conclusion, MRI has significantly higher sensitivity than CT for detecting cartilage invasion in patients with laryngo-hypopharyngeal cancer, without a significant difference in the specificity.

KEY POINTS

• MRI has significantly higher sensitivity than CT for detecting cartilage invasion in patients with laryngo-hypopharyngeal cancer.