When to prescribe for elevated PSA
An increase in prostate-specific antigen is not equivalent to cancer: prostatitis, adenoma, recent cycling, and even ejaculation on the eve of the test give the same result. The question arises of who and where to perform the biopsy, because the standard scheme takes material along a formal grid and may bypass a small lesion.
Elastography is performed with a transrectal sensor simultaneously with TRUS and shows the distribution of stiffness across the gland zones. Cancer most often develops in the peripheral zone and appears as a localized area of increased density. Having found such an area, the doctor can add targeted injections into the standard pattern, which increases the likelihood of detecting a tumor.
The limitation of the method is chronic prostatitis and previous interventions: scars and foci of inflammation are also hard and give false positive zones. Therefore, the result is always interpreted together with the PSA level, digital examination data and, if possible, pelvic MRI.
What does elastography show?
Elastography measures the stiffness (elasticity) of tissue - a parameter that a doctor could previously assess only with his hands during palpation. Healthy tissue is soft and easily deformed, while scar, fibrous and tumor tissue is dense and rigid. The method translates this feeling into objective numbers that can be compared between studies.
The main practical value is in the differential diagnosis of focal formations. Benign nodes usually retain the elasticity of the surrounding tissue, while malignant ones are noticeably stiffer. This helps decide which nodes need to be monitored and which ones require a biopsy.
Compression and shear wave techniques
Compression elastography is based on light pressure with a sensor: the device compares tissue deformation and builds a color map. The method is qualitative - it shows what is harder and what is softer, but does not give absolute values.
Shear wave elastography (shear wave, which also includes liver fibroscan) uses the acoustic pulse of the device itself and measures the speed of propagation of the shear wave. The result is quantitative - in kilopascals, which allows you to track the dynamics during treatment.
Limitations of the method
The result is influenced by severe obesity, edema and active inflammation in the area of interest, as well as the depth of the formation: the deeper it is, the less reliable the measurements. Large calcifications and cysts produce artifacts.
Elastography is not an independent diagnosis, but one of the parameters. The final conclusion about the nature of the formation is given by a morphological study, that is, a biopsy.