Ultrasound: How it’s used to find an Abnormality
Guest: Dr. Susan Ackerman – Radiology, MUSC
Host: Dr. Linda Austin – Psychiatry, MUSC
Dr. Linda Austin: I’m Dr. Linda Austin. I’m interviewing Dr. Susan Ackerman, who is Associate Professor of Radiology and Director of Ultrasound here at MUSC. Dr. Ackerman, we’ve been talking about ultrasound. Is it an expensive technology?
Dr. Susan Ackerman: It’s not expensive compared to most other imaging modalities. It’s probably one of the least expensive studies, other than just a plain film x-ray. And that’s one reason why physicians will order an ultrasound; perhaps as a screening study when they don’t have a high suspicion of an abnormality. Ultrasound helps to exclude a problem. And it’s certainly much cheaper than a CT or an MRI. In addition, it doesn’t use radiation. It’s very portable, as we mentioned earlier. You can actually take it to a setting, an intensive care unit room, or an operating room. It’s helpful to surgeons for localization or resection of a certain area.
Dr. Linda Austin: Oftentimes, patients, I think, get confused about why there has to be so many studies; several different studies. You just mentioned that it’s used, sometimes, as a preliminary screening study. What would happen, for example, if there was a suspicion? What would be the next step in making a diagnosis?
Dr. Susan Ackerman: Well, it depends on where the abnormality is. If a patient had an abnormality in the liver; perhaps we saw a mass in the liver and were concerned about it, the next step would likely be an MRI, which is very good at characterizing liver lesions, particularly benign versus malignant. Ultimately, many of those patients need a tissue diagnosis or a biopsy of the lesion to make a decision. Ultrasound can be helpful, at least initially, in finding an abnormality. Now, having said that, if there’s a high suspicion of a problem and the ultrasound is negative, then the physician may order a more in-depth study, such as a CT or an MRI, particularly if there’s question of a liver lesion.
Dr. Linda Austin: Now, for something like following cancer patients after chemotherapy, that’s typically done by CAT scan, not ultrasound? Am I right about that?
Dr. Susan Ackerman: That’s true. The one area where ultrasound is typically used to follow up patients after cancer resection and therapy is ultrasound of the neck. We have a large number of thyroid cancer patients at our institution. These post-thyroidectomy patients come, usually, every 6 to 12 months for an ultrasound evaluation of the neck to look recurrence of tumor, either in the thyroid bed or of lymph nodes. Ultrasound is very good for that.
In general, if it’s a superficial structure, then ultrasound is usually fairly good, because, remember, it uses sound waves to try to find the abnormality. The more superficial, or closer, the structure is to the transducer that’s sending the sound waves out, usually the easier it is for ultrasound to find it.
Dr. Linda Austin: So, does that mean you would never use it on the skull, for example?
Dr. Susan Ackerman: We actually do use ultrasound when we’re looking at pediatric patients, for instance, in neonatal intensive care, when we’re looking for brain hemorrhages and at pediatric patients born prematurely. And those are read by the pediatric radiologist. They do the pediatric ultrasound.
Dr. Linda Austin: Fascinating. Thanks so much for explaining this.
Dr. Susan Ackerman: Thank you.
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