Decreased diaphragm moving distance measured by ultrasound speckle tracking reflects poor prognosis in amyotrophic lateral sclerosis.

OBJECTIVE

Decreased cephalocaudal diaphragm movement may indicate respiratory dysfunction in amyotrophic lateral sclerosis (ALS). We aimed to evaluate diaphragm function in ALS using ultrasound speckle tracking, an image-analysis technology that follows similar pixel patterns.

METHODS

We developed an offline application that tracks pixel patterns of recorded ultrasound video images using speckle-tracking methods. Ultrasonography of the diaphragm movement during spontaneous quiet respiration was performed on 19 ALS patients and 21 controls to measure the diaphragm moving distance (DMD) in the cephalocaudal direction during a single respiration. We compared respiratory function measures and analyzed the relationship between the clinical profiles and DMD.

RESULTS

DMD was significantly lower in ALS patients than in the control group (0.6 ± 1.4 mm vs 2.2 ± 2.2 mm,  < 0.01) and positively correlated with phrenic nerve compound motor action potential amplitude (R = 0.63,  = 0.01). DMD was negatively correlated with the change in the ALS Functional Rating Scale-Revised scores per month after the exam (R = -0.61,  = 0.02), and those with a larger rate of decline had a significantly lower DMD ( = 0.03).

CONCLUSIONS

Diaphragm ultrasound speckle tracking enabled the detection of diaphragm dysfunction in ALS.

SIGNIFICANCE

Diaphragm ultrasound speckle tracking may be useful for predicting prognosis.