[Ultrasound examination of the breast with 7.5 MHz and 13 MHz-transducers: scope for improving diagnostic accuracy in...

Complementary diagnostic methods in early diagnosis of breast cancer are used to increase diagnostic accuracy and minimize unnecessary invasive diagnostic procedures. Aim of the following prospective, open multicenter clinical study was to define the value of high-frequency breast ultrasound with 13 MHZ transducers compared to standard breast ultrasound with 7.5 MHz.

Data of 810 female patients, aged 45 to 60 years, with 819 suspicious breast lesions evaluated by four participating centres between October 1996 and December 1997. Standardised breast ultrasound was performed uniformly using a AU4 IDEA diagnostic ultrasound system by Esaote-Biomedica in addition to a standardised procedure of clinical examination and standard-2view-mammography. Analysis of all aquired data and the correlating histopathological findings was done by means of descriptive statistics on the basis of an access datafile (Version 2.0).

The histopathological evaluation showed 435 benign and 384 malignant findings. Overall sensitivity and specificity of the clinical examination were 71.1 % and 88.9 % and for mammography 84.7 % and 76.5 %, respectively. Standard ultrasound with 7,5 MHz reached a sensitivity of 82,6 % and a specificity of 80.8 % high-frequency ultrasound with 13 MHz came to 87.2 % and 78.4 %, respectively. Regarding tumour size, mammography gave the highest sensitivity in detection of pre-invasive cancers (DCIS). High-frequency breast ultrasound (13 MHz) proved to have a higher diagnostic accuracy compared to standard breast ultrasound (7,5 MHz) regardless of tumour size. Sensitivity was especially improved in case of small invasive tumours (pT1a) with 78 % versus 56 %, respectively.

We conclude that high-frequency ultrasound is a valueable additive tool especially in the diagnosis of small tumours, improving diagnostic safety and reducing unnecessary invasive diagnostic procedures.