Many patients will be referred to Melbourne Radiology Clinic for the purposes of obtaining a “tissue diagnosis”. This occurs in the setting where a patient has had a scan that has detected a focal abnormality of an organ. By taking a sample of tissue, a medical specialist known as a pathologist can review the tissue under a microscope and provide an answer as to what is the cause of abnormality seen on the patient’s scans.
Though most radiology scans can often diagnose what a lump in the body may be, it is often prudent to take a small sample to ensure that the abnormality is benign and not cancer. With recent developments in needle technology, many tissue samples can be performed safely and with minimal risk. One advantage of taking a specimen of tissue is that once an abnormality is proven to be benign, then often no further imaging follow up is necessary and therefore reduces patient anxiety and expense. Imaging is used to safely and reliably guide the needle into the appropriate location and may be performed under CT, X-ray or ultrasound guidance.
Tissue samples may be made with either a Fine Needle Aspiration (FNA) or biopsy. Discomfort is usually minimal and both procedures usually feel no different to a patient. The main difference is that a biopsy will take a solid core of tissue with a specific needle and the sample is excellent, allowing the pathologist to make a confident diagnosis without the need for recalling the patient or taking multiple samples. The disadvantage however is bleeding, as a larger specimen of tissue is obtained. On the other hand, an FNA is minimally invasive with a thin needle (hence the name) and is used for organs which have a rich blood supply, such as the thyroid gland. The disadvantage is that only small fragments of tissue are removed with the needle and thus an inadequate specimen may be obtained that is insufficient to confidently diagnose a benign or malignant process.
The decision whether to perform a biopsy or FNA is usually made by the referring doctor and/or radiologist depending on the question that needs to be answered, the body part and the ease of access to this area.
For more information read the Melbourne Radiology Clinic - Patient Fact Sheet on Fine Needle Aspiration or Biopsy.