Ultrasound elastography (synonyms: sonoelastography; ultrasound-assisted elastography; ultrasound elastography) is a diagnostic procedure in urology that can be used, among other things, to detect tumors when prostate cancer is suspected. The functional principle of ultrasound elastography is based on the detection of a change in the elasticity of the tissue, which can primarily indicate a neoplastic change (cancer-related neoplasm). Elasticity testing is used to differentiate the varying degrees of mechanical hardness.
Indications (areas of application)
- Ultrasound elastography of the prostate – Ultrasound elastography for the detection of tumors of the prostate is a very specific method because the procedure allows visualization of not only enlargement but also greater mechanical hardness during transrectal examination. However, the method is not used alone due to its insufficient informative value. By combining ultrasound elastography with the evaluation of PSA values (prostate specific antigen; PSA) and other diagnostic procedures, the accuracy of the diagnosis is significantly increased compared to the digital prostate examination (palpation).
- Breast cancer – Ultrasound elastography is now considered a proven method to characterize focal lesions (damage or change to a specific delineated area of tissue) of the breast.
- Inflammation – In inflammatory processes, the procedure can be used organ nonspecifically due to a tissue elasticity change.
- Liver – Elastography of the liver (fibrosan; ultrasound procedure that measures the degree of connective tissue in the liver); used to assess the stage of liver fibrosis.
Contraindications
- There are no known contraindications to the use of the procedure.
Before the examination
The procedure represents a non-invasive procedure for which no preparatory measures need to be performed by the patient.
The procedure
Ultrasound elastography can be used to obtain sonographic images at a defined compression, allowing a meaningful evaluation of the tissue. The basic principle of the procedure is based on the evaluation of tissue displacements on ultrasound images, so that the displacements of body tissue between two ultrasound images can be calculated. It is essential that the sonographic images are acquired with varying compression. Thus, an accurate assessment of the elasticity of the examined tissue is achieved, based on strain images. During the repetition and subsequent evaluation of the examination, it is necessary to always record the generated compression of the tissue in addition to the elasticity. The procedure is suitable as part of a general prostate screening examination. Particularly in prostate diagnostics, it is crucial for the informative value of the procedure that local indurations can be precisely visualized to enable an exact differentiation between physiological tissue and pathologically altered tissue. Image artifacts (distortions), which can occur, for example, due to lateral deviation of tissue areas during compression, must be compensated for in the procedure by a special method in order to avoid obtaining false results. In breast diagnostics, pathological changes associated with reduced elasticity can be depicted as relative tissue displacement (strain) or quantitative propagation of shear waves in the tissue (shear wave elastography, SWE). In the case of malignancy, the tumor appears larger in the elastogram than in the B-mode ultrasound image. Elastography is used in the liver to assess liver fibrosis stage.
After the examination
- Following the procedure, no special measures need to be performed. If tumor or inflammation is suspected, further diagnostic procedures are used.
Possible complications
- Ultrasound elastography is based on sonography, so no harmful radiation is released.
