M-mode sonography of diaphragmatic motion: description of technique and experience in 278 pediatric patients

BACKGROUND

The use of M-mode sonography for evaluation of diaphragmatic motion has only been previously reported in small series of children, and its use is not widespread among pediatric radiologists.

OBJECTIVES

To present our experience with M-mode sonography in the evaluation of diaphragmatic motion in a large number of children with suspected diaphragmatic paralysis, to describe the technique used and to correlate sonographic findings with chest radiographs and clinical outcome.

MATERIALS AND METHODS

Retrospective analysis of all M-mode sonograms performed in children from September 1999 to December 2003. The available chest radiographs and the clinical findings were reviewed and correlated with the sonographic findings.

RESULTS

A total of 742 hemidiaphragms were evaluated in 278 children. There was no visualization of the left hemidiaphragm in 2 children (0.71%). Movement of the right hemidiaphragm was normal in 238 and abnormal in 131. Movement of the left hemidiaphragm was normal in 232 and abnormal in 135. Abnormal diaphragmatic movement was present in 118 (63%) of 187 children in whom chest radiographs had shown normal position of the hemidiaphragms. Follow-up examinations were obtained in 56 children, revealing improvement in diaphragmatic motion in 26, no change in 23 and deterioration of motion in seven.

SUMMARY

M-mode sonography should be the modality of choice to assess diaphragmatic motion, as it can easily depict diaphragmatic dysfunction and allows comparison of changes in follow-up studies. Normal chest radiographs are poor predictors of normal diaphragmatic motion.

Comparison of ultrasound with fluoroscopy in the assessment of suspected hemidiaphragmatic movement abnormality

A comparative study of quantitative hemidiaphragmatic ultrasound with fluoroscopy was undertaken in 30 patients referred for investigation of suspected hemidiaphragmatic movement abnormality. The aim of this study was to determine whether assessment with ultrasound or fluoroscopy differed, and which technique appeared more suitable in the investigation of hemidiaphragmatic movement disorder. There were four technical failures using fluoroscopy (13%), compared with none using ultrasound. Using the normal ranges of right to left ratio of maximal excursion (0.5-2.0 for fluoroscopy and 0.5-1.6 for ultrasound) there was concordance in 21 out of 26 (81%) patients. All cases of abnormality on fluoroscopy were seen on ultrasound. Four of the discordant cases had excursions on the lesser side in the normal range on ultrasound suggesting a milder movement abnormality detected by ultrasound than by fluoroscopy. Sniff testing conferred no advantage over quantitative testing. Ultrasound has technical, qualitative and quantitative advantages over fluoroscopy and should be the method of choice in the investigation of suspected hemidiaphragmatic movement abnormality.

Pulmonary sequestration: the value of ultrasound

A child presented with a chest infection. A chest radiograph showed consolidation in the left lung base. This failed to clear in spite of adequate antibiotic therapy. Ultrasound examination (real-time) suggested pulmonary sequestration, and an aberrant blood supply was demonstrated. Subsequent angiography, surgery and pathological examination of the resected segment confirmed this.

Ultrasonographic demonstration of systemic artery feeding extrapulmonary sequestration

An extralobar pulmonary sequestration in an infant was diagnosed by ultrasound. The sequestration appeared as an echogenic mass interpositioned between the liver and the right lung. The main feeding vessel of the sequestration was demonstrable. Ultrasound should be the first diagnostic modality used for evaluation of a supraphrenic chest mass seen on chest roentgenogram in childhood.