Diagnosis Of Digital Clubbing By High Frequency Ultrasound Imaging

Background: The current used methods for diagnose of clubbing havedrawbacks. This study is to test a novel and convenient method for thediagnosis of digital clubbing using high frequency ultrasound.Methods: The index fingers from a healthy control group without digitalclubbing and a patientgroup with digital clubbing were examined byultrasound. The morphology of the clubbingfingers was observed. The softtissue depth under the nail (SDUN), the interphalangeal depth(IPD) and thedistal phalangeal depth（DPD) were measured. The ratio of DPD andIPD(DPD/IPD) was calculated.Results: The nails, the soft tissue under the nails, the digital bones and thedigital joint were clearly observed by ultrasound. The mean SDUN was0.16±0.01cm for the control group and0.284±0.02cm for the patient group(p<0.01). By both naked eyes observation and ultrasoundmeasurement ofthe ultrasound images, the SDUNs in patient group were bigger than theSDUNs in the healthy control group. The DPDs were bigger than the IPDs in the patient group, while in the healthy control group, the DPDs weresmaller than the IPDs. The mean DPD/IPD ratio was0.86±0.04cm in thecontrol group and1.077±0.11cm in the patient (p<0.05).Conclusion: We present a new, easy and convenient method for thediagnosis of Digitalclubbing using ultrasound. We also found a new parameter, the SDUN, forthe diagnosis of clubbing fingers and the identification of pseudo digitalclubbing. The early SDUN might be taken as an early sign of digitalclubbing.