Left hemidiaphragmatic mobility: assessment with ultrasonographic measurement of the craniocaudal displacement of the splenic hilum and the inferior pole of the spleen.

Objective: The purpose of this study was to evaluate the correlation between the radiographic and ultrasonographic measurements of craniocaudal displacement of the left hemidiaphragm.

Methods: Forty-nine patients with clinical indications for interventional procedures prospectively underwent radiographic evaluation of left hemidiaphragmatic mobility and B-mode ultrasonographic measurement of craniocaudal displacement of the hilum and the inferior pole of the spleen. Ultrasonography was performed with a 3.5-MHz convex transducer in a left intercostal position under a longitudinal orientation. Statistical analyses were performed with linear regression, a paired Student t test, and Bland-Altman analyses.

Results: The correlation between the craniocaudal splenic hilum displacement and radiographic measurements was found to be linear: hemidiaphragmatic mobility = 17.795 + 0.429 x splenic hilum displacement (SE for the regression coefficient = 0 .12; P = .0012), although the values obtained with both methods were statistically different (P < .05). The same results could be observed with the use of the inferior pole of the spleen: hemidiaphragmatic mobility = 9.5596 + 0.5455 x inferior polo displacement (SE for the regression coefficient = 0 .11; P < .0001). The mean difference between the values obtained by ultrasonography and by radiography was statistically significant (16.7 +/- 16.1 mm; P < .05 [hilum]; 18.9 +/- 14.2 mm; P < .05 [inferior pole]).

Conclusions: These results allow us to conclude that ultrasonography can be used as an alternative method for left hemidiaphragm mobility evaluation compared with radiography.