Evaluation of the pulmonary radioaerosol mucociliary clearance scan as an adjunctive test for the diagnosis of primary ciliary dyskinesia in children

Abstract

Introduction The accuracy of primary ciliary dyskinesia (PCD) diagnosis has improved but no single test is diagnostic and some cases remain unsolved. Data regarding the accuracy of pulmonary radioaerosol mucociliary clearance scan (PRMCC) for the diagnosis of PCD are limited to predominantly adults using a 24‐hour test. This study was performed to determine the accuracy of a 60‐minute PRMCC test for diagnosing PCD in children. Methods Children with suspected PCD and inconclusive clinical diagnostic testing in an expert center were selected for PRMCC testing. Nebulized 99mTc sulfur colloid was inhaled and dynamic imaging acquired for 60 to 120 minutes. Two independent radiologists blinded to the clinical diagnosis and health records overread PRMCC studies. The PRMCC result was compared with the reference standard diagnosis of PCD made by two physicians using the cumulative health record, blinded to PRMCC results. Results From 2008 to 2018, 57 patients (6‐17 years) participated, of which 16 met criteria for the reference diagnosis of PCD. The PRMCC test was conclusive in 54 patients (94.7%) and had a sensitivity of 100% (95% confidence interval [CI] = 78.2–100), specificity of 85.7% (95% CI = 69.7–95.2), positive predictive value of 75% (95% CI = 57.1–87.1), negative predictive value of 100% (95% CI = 90.2–100), and accuracy of 90% (95% CI = 78.2–96.7). Conclusion The 60‐minute PRMCC test is noninvasive and feasible in children with a high negative predictive value for PCD. It may be a helpful adjunctive test to rule out PCD when clinical suspicion remains after guideline recommended first‐line clinical testing.

Pulmonary Radioaerosol Mucociliary Clearance Parameters as Potential Outcomes in Primary Ciliary Dyskinesia Trials

“…In relation to this, PRMC results has also not been shown to be associated with lung function (FEV 1 ), as previously investigated by Vali and colleagues (9).…”

“…Our study provides new insight into the use of the PRMC test as a potential supplier of outcome parameters for clinical trials. It is well established that PRMC discriminates significantly between PCD and health (5, 7-9), and without losing diagnostic capability even if the PRMC test is shortened to a 60-minute test (9). PRMC test results related to PCD genotypes has not been described until now.…”

“…In previous studies PRMC has shown high sensitivity to predict PCD and as a strong tool to rule out PCD in non-PCD cases, applicable to children as young as 5 years of age (5)(6)(7)(8)(9).…”

Pediatric pulmonology 2019 year in review: rare and diffuse lung disease

“…Investigators from The Hospital for Sick Children in Toronto studied the use of a 60-min pulmonary radioaerosol mucociliary clearance scan (PRMCC) for the diagnosis of PCD in children. 60 In PRMCC, the patient inhales radiolabeled sulfur colloid, and its clearance is assessed by dynamic imaging for 60-120 min. Previous studies have examined a 24-h test in adult patients, [61][62][63] and European guidelines suggest this study for patients in whom first-line testing is nondiagnostic.…”

“…Measuring ciliary function in vivo through imaging offers another potential diagnostic avenue for PCD. Investigators from The Hospital for Sick Children in Toronto studied the use of a 60‐min pulmonary radioaerosol mucociliary clearance scan (PRMCC) for the diagnosis of PCD in children 60 . In PRMCC, the patient inhales radiolabeled sulfur colloid, and its clearance is assessed by dynamic imaging for 60–120 min.…”