[Tissue harmonic imaging and contrast harmonic imaging. Improving the diagnosis of liver metastasis?]

Harmonic versus conventional ultrasound imaging of the urinary tract in children

BACKGROUND

Harmonic imaging (HI) is a relatively new US method. Its usefulness in children has yet to be determined.

OBJECTIVE

To evaluate the value of HI in urinary tract imaging of infants and children.

MATERIALS AND METHODS

The bladder and kidneys of 29 unselected patients, aged 2 months to 12.8 years (mean, 6.8 years), were examined from ventral and dorsal approaches using conventional (= fundamental) imaging (FI) (6.5 and 3.4 MHz) and HI (3.3 MHz). In addition to global image quality, visualization of bladder wall, retrovesical space, renal contrast to liver/spleen, the pelvicalyceal systems, and the difference between cortex and medulla were assessed. Parameters were rated by two independent examiners and statistical analysis was performed.

RESULTS

There were significant differences between the three imaging settings for all parameters studied (P<0.003). With the dorsal approach, HI was superior to FI for all parameters analysed (P<0.05). Using the ventral approach, a significant improvement of imaging with HI was found for the bladder and the renal pelvis (P<0.02).

CONCLUSIONS

HI is a useful additional tool for imaging the urinary tract in children of all ages. The method particularly improves visualization of the bladder and the kidney from a dorsal approach.

Phase-inversion tissue harmonic imaging compared to fundamental B-mode ultrasound in the evaluation of the pathology of large and small bowel

Our purpose was to compare phase-inversion harmonic imaging (PIHI) with conventional B-mode ultrasound (US) regarding image quality in the evaluation of bowel pathology. Forty-one patients prospectively underwent intestinal ultrasound scans with US and PIHI in randomly chosen order. Crucial technical parameters were standardized. Bowel morphology as well as perienteric pathology and complications were documented. In 24 cases, the ultrasound results were compared to those of other imaging modalities. Three radiologists evaluated (1) overall image quality, (2) lesion conspicuity and diagnostic confidence, and (3) detection of free fluid on hardcopy films. The ratings for image quality were compared using the two-sample paired t test for means and Bowker's test for symmetry (p=0.05). Compared to US, PIHI provided significantly better overall image quality, lesion conspicuity and diagnostic confidence, as well as better detection of free fluid (p< 0.05). Bowel wall pathology, detected by both modalities, showed good correlation to additional imaging modalities. In 12 patients (29.3%), a gain of crucial diagnostic information was observed with PIHI when compared to US. PIHI significantly enhances sonography of the intestine by offering better overall image quality, better visualization of bowel pathology and associated changes. Additionally, PIHI adds crucial diagnostic information in several patients.

[Current developments in ultrasound technology]

This review of contemporary technical developments in diagnostic ultrasound deals with methods of ultrasound signal acquisition, signal generation (encoding technologies), image compounding (panoramic view techniques), microtechnology (systems with improved handling and ergonomics), dedicated ultrasound contrast techniques, and developments of ultrasound probe technology.

Diagnostic accuracy of phase-inversion tissue harmonic imaging versus fundamental B-mode sonography in the evaluation of focal lesions of the kidney

OBJECTIVE

We compared phase-inversion tissue harmonic imaging with fundamental B-mode sonography in the evaluation of focal lesions of the kidney.

SUBJECTS AND METHODS

For our prospective study, 114 patients underwent sonography of the kidneys in both modes, fundamental B-mode sonography and phase-inversion tissue harmonic imaging, in a randomly chosen scanning order. Imaging parameters were standardized. Sonographic diagnoses were made under real-time conditions by the examining radiologist. All sonographic diagnoses were compared with a diagnostic reference modality: contrast-enhanced CT, contrast-enhanced MR imaging, or histopathology. Three radiologists different from the examiners evaluated overall image quality, lesion conspicuity, and fluid-solid differentiation for both modalities using hard-copy images.

RESULTS

In 70 patients, fundamental B-mode sonography as the first technique depicted 73 of 111 lesions 10 mm or larger and enabled 71 lesions to be correctly characterized (sensitivity, 65.8%; accuracy, 64.0%). As the first mode, phase-inversion tissue harmonic imaging depicted 57 of 65 focal lesions and enabled 54 lesions to be accurately classified in 44 patients (sensitivity, 87.7%; accuracy, 83.1%). The differences in sensitivity and accuracy were statistically significant (95% confidence interval). For overall image quality, lesion conspicuity, and fluid-solid differentiation phase-inversion harmonic imaging was superior to fundamental B-mode sonography (p < 0.0001).

CONCLUSION

Phase-inversion tissue harmonic imaging is superior to fundamental B-mode sonography in the sonography of focal kidney lesions because phase-inversion tissue harmonic imaging has better overall image quality, lesion conspicuity, and fluid-solid differentiation. In six cases, phase-inversion tissue harmonic imaging added crucial diagnostic information that changed patient management.