In the world of radiology, body imaging is one of many subspecialties. In most cases, radiologists use body imaging to diagnose diseases and conditions of the organs found in the chest, abdomen and pelvis, including the liver, pancreas, kidneys, bladder, stomach, intestines, heart and lungs, among others. Specific scanning techniques are used to tailor-fit each organ, allowing for highly detailed results.
The Magic is in the Modality
When performing body imaging on the liver and other organs, radiologists may use a variety of modalities, including ultrasound, computed tomography (CT or CAT) scan and magnetic resonance imaging (MRI).
- Ultrasound – This modality is a non-invasive, diagnostic exam for which the imaging technician uses a transducer (wand-like instrument) that is placed on and moved over the skin. Ultrasound waves then move through the body and bounce off organs to produce computer images of internal structures. No radiation is used for ultrasound.
- CT Scan – CT scan is known as the “workhorse of body imaging” because it is widely available in hospitals and radiology practices, and it can be completed quickly. While the CT scan uses radiation via rotating X-ray machines to create images of organs and tissues, it only requires the patient to lie still for a short amount of time. CT scan is excellent at providing spatial resolution and “the view from 30,000 feet,” so to speak, but sometimes issues arise that will need more investigation, and MRI is often the next step in that process.
- MRI – Often known as the problem-solving tool for body imaging, MRI uses magnetic forces and radio waves to produce gradient-weighted images of a patient’s organs and internal structures. Without the use of radiation, MRI produces high-quality, clear pictures so that radiologists can determine in much greater detail what might be happening within a certain organ or tissue. However, patients must lie still in a tube-like machine for an extended period of time so that the radiologist can obtain effective results.
“My Doctor Says I Have a Liver Mass – Now What?”
The liver is one organ that is frequently scanned by body imaging radiologists. In fact, 10 to 15 percent of the population experience benign or non-cancerous liver cysts, and body imaging is an essential method used for examining this condition.
The power of using MRI on the abdomen was first shown through, and continues to be essential in, the examination of liver masses. Liver masses are incredibly common and are typically detected when a patient is being examined for another health issue, rather than for the liver itself.
“Often, we find that liver masses are incidental findings, like when a patient goes in for a CT scan after experiencing abdominal pain,” explained Dr. Jay Alley, neuroradiologist and abdominal imaging radiologist with Raleigh Radiology. “In other words, we might be looking for appendicitis, diverticulitis, or kidney stones, and then notice a mass on the liver.”
Other times, liver mass detection is simply related to the body’s anatomy. For example, in performing a chest CT scan, portions of liver are imaged which may reveal an abnormality that needs further workup with CT or MRI.
“The beauty of MRI is that it can provide such good soft tissue resolution that we are able to analyze lesions or masses that are even very small,” said Dr. Alley. “However, some can be too small, and we might take another look in three to six months to see if anything changes.”
During an MRI, multiple images will be taken of the liver, with intravenous contrast being injected about three-fourths of the way through the exam. Intravenous contrast is a special liquid medication that is injected into the patient’s vein. It travels through the blood vessels and highlights those areas being examined. If certain areas enhance and become conspicuous (or light up brighter), the radiologist will gain more information about the mass.
Different Types of Liver Masses
During an MRI for a liver mass, the radiologist wants to determine if the mass is solid, cystic (filled with fluid) or both. The challenge is knowing what these different types of liver lesions look like when imaged on various MRI sequences, as well as the way they react to intravenous contrast. This is where the radiologist’s body imaging experience and years of training come into play.
The types of liver masses include:
Benign Hepatic Cyst – A fluid-filled sac that forms in the liver. It is not cancerous, rarely requires treatment and typically does not affect liver function.
Hemangioma – The most common type of benign liver tumor. Hemangiomas are actually non-cancerous tangles of blood vessels. These are common, do not cause symptoms, rarely need treatment, and do not spread to other areas of the body.
Malignant Liver Mass – A mass that is cancerous. Radiologists typically can determine if a mass or lesion in the liver is malignant when it shows early peripheral (around the edge) enhancement with contrast that fades or washes out quickly.
“Like a parasite, a malignant mass or tumor has a way of taking over the adjacent blood vessels to use them for its own purposes and to make itself grow,” explained Dr. Alley. “As such, the enhancement from MRI contrast will show a variation in the vascular pattern within that region. If the blood supply is trying to go there, we know that something is trying to grow and that the mass is likely cancerous.”
Other less common findings on an MRI of the liver include focal nodular hyperplasia (FNH) and hepatic adenoma, both of which are non-cancerous, solid lesions that can develop on the liver. These are typically left untreated, unless they need to be removed due to size and/or propensity to bleed.
“I tell patients that a growth on the liver is generally nothing to worry about, and I am grateful that we have a body imaging tool like MRI to effectively rule out serious complications or alert the need for further treatment,” said Dr. Alley. “In my experience, approximately 80 percent of the time, liver masses are benign cysts or hemangiomas, which are common, non-cancerous lesions.”
However, for patients who do receive the news about a possible malignant lesion, a biopsy would likely be the next step, after being referred to a surgical oncologist or hepatologist. If caught early, the tumor can often be surgically removed before the cancer spreads to other areas of the body.
For more information about the body imaging services provided by Raleigh Radiology, visit www.raleighrad.com.
Sources:
Body Imaging – OHSU
https://www.ohsu.edu/school-of-medicine/diagnostic-radiology/body-imaging
Body Imaging – Johns Hopkins Medicine
https://www.hopkinsmedicine.org/radiology/specialties/body-imaging/
Liver Hemangioma – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/liver-hemangioma/symptoms-causes/syc-20354234
Benign Liver Tumors – American Liver Foundation
https://liverfoundation.org/for-patients/about-the-liver/diseases-of-the-liver/benign-liver-tumors/
Focal nodular hyperplasia – Radiopaedia
https://radiopaedia.org/articles/focal-nodular-hyperplasia?lang=us#:~:text=Focal%20nodular%20hyperplasia%20(FNH)%20is,may%20be%20atypical%20in%20appearance.
