Magnetic Resonance Imaging (MRI):
We use state of the art magnetic resonance imaging equipment and imaging protocols to examine diseases of the abdomen and pelvis. We routinely do MRI for characterization of focal masses of the liver, kidneys and pancreas, metastatic surveys for tumors, and evaluation of female reproductive organs among other things. We also use MR for more advanced applications such as quantitative and qualitative assessment of liver fat, iron, and fibrosis, and diagnosis and staging of certain cancers such as rectal, prostate, and cervical cancer and hepatocellular cancer. We also perform MR enterography for small bowel diseases, MR defecography for female pelvic floor dysfunction, and MR angiography for pre and postoperative evaluation of renal transplants - using novel intravascular contrast agents. Our dedicated MR service is staffed by abdominal radiologists with subspecialty training in body MRI working in conjugation with an abdominal imaging fellow. The MR team is led by Dr. Mike Corwin who works closely with clinical colleagues to develop specific MR protocols to best serve our patients.
Computed Tomography (CT):
The abdominal section employs state of the art, reduced radiation dose protocols and 64 slice or greater multidetector row CT equipment to image a plethora of abdominal and pelvic pathologies. It is our mainstay for trauma imaging, cancer surveillance, vascular pathologies, and abdominal pain evaluation. In addition to routine abdominal pelvic CT’s, we perform specialized CT’s including CT enterography for small bowel pathology, CT urography for evaluation of the urinary tract, and CT colonography for non-invasive and sedation free colon cancer screening. The CT team is led by Dr. Ramit Lamba whose vision was to design unique CT protocols that have been designed and optimized to address specific and unique clinical questions. We thus employ over 35 CT protocols to provide high quality patient specific imaging. All CT exams are interpreted by fellowship trained subspecialty abdominal radiologists, with contemporaneous training of residents and fellows.
In addition to routine abdominal-pelvic, head and neck, scrotal and early pregnancy ultrasounds, some members of the abdominal section partner with a stellar maternal and fetal medicine division at UC Davis to interpret second and third-trimester obstetrical ultrasounds. Advanced ultrasound techniques, including elastography for liver fibrosis evaluations, sono-hysterograms, and contrast-enhanced ultrasound, are also a routine part of our practice. John McGahan, who is a member of our ultrasound team is nationally and internationally recognized for his contributions to general and obstetric ultrasound. An excellent dedicated team of sonographers takes great pride in providing compassionate care for our patients.
The art of Fluoroscopy is a time-honored tradition in radiology. At UC Davis, we take care to obtain the best quality images while maintaining low radiation dose to the patient. Our recently acquired Fluoroscopy machine has remote control abilities, that provides a unique experience both for the patient and the operator. It also allows recording of the real time physiologic events (such as swallowing and transit of contrast of contrast in the bowel) thus reducing the need for spot images, further decreasing radiation dose to the patient. We routinely perform fluoroscopic evaluations of the GI tract including the esophagus, the urinary tracts, and male urethra for a variety of clinical reasons including evaluation of perforations and leaks form the GI tract. We also have a small cadre of radiologists who specialize in performing contrast evaluations of the uterus and fallopian tubes (hysterosalpingography). Our subspecialized team works cohesively with a caring team of technologists to optimize the care of our patients.
Cross-Sectional Interventional Radiology (CSIR):
Our dedicated team of cross-sectional interventional radiologists performs a wide range of procedures that are done using cross sectional imaging guidance (Ultrasound and CT), which include biopsies of abdominal pelvic masses, lymph-nodes, thyroid nodules, head and neck masses, native and transplant kidneys, tumor ablations, and aspiration and drainage of fluid collections. These procedures often circumvent invasive surgery, need for general anesthesia and hospital admission. We offer cancer patients minimally invasive tumor biopsies to obtain tumor samples that are used to direct both clinical treatments as well as research trials. Our team of dedicated interventionalists is led by Dr. Sima Naderi and prides itself in extremely skilled use of ultrasound, which is used to guide the majority of our interventional procedures thus avoiding any exposure to radiation. When using CT, we employ state of the art CT Fluoroscopy to minimize procedural radiation dose.
In addition, we perform image-guided tumor ablation as a treatment option for cancer. This minimally invasive technique can obviate major surgery. We use both thermal (radio frequency waves and microwave’s) and cooling techniques (cryoablations) for tumor ablations. Thermal ablations are widely used by our team to destroy small primary liver tumors (hepatocellular carcinoma), liver metastases, and renal and adrenal neoplasms. Apart from being excellent alternatives to surgery these techniques can be crucial to treat patients who are deemed to be a high risk for surgery and can also be used to treat recurrences of previously treated tumors. The ablation team is led by Dr. John McGahan who pioneered the use of radio-frequency ablation in his lab in the early 90’s. A dedicated team of nurses is committed to providing the best possible experience and painless recovery for our patients.
Radiofrequency ablation is a treatment that uses radio waves to create heat and directs the heat though a needle probe at cancer cells to destroy tumors.
Radiofrequency ablation (RFA) is minimally invasive, meaning it involves having to enter the body with a needle rather than an incision, as with major surgery. Because of this and its ability to create heat in a specific location, RFA is a good treatment choice for patients with many different types of cancer.
One of the cancers treated most by RFA is cancer of the liver. In many cases, removing the tumor with surgery would not leave enough healthy tissue for the liver to still function. Primary liver tumors such as hepatomas in patient with hepatitis or liver tumors that spread (metastasize) from cancers that started somewhere else in the body are good candidates for RFA. In some cases, a previous attempt to treat the tumor, such as with chemotherapy, has failed and RFA is the next option. RFA also might be used to treat a tumor that has recurred. Severe liver disease or other factors may make surgery an increased risk to certain patients and RFA can be a good alternative.
Many patients with kidney tumors have surgery, but some patients only have one kidney, making RFA the preferred treatment, since it helps spare the remaining kidney. As with other organs, RFA is an excellent alternative for patients who have conditions that might prevent them from having surgery or for whom recovery from surgery would be difficult. RFA for kidney (renal) cancer is an excellent choice for patients with more than one tumor, if the tumors are small.
Radiofrequency ablation of the lung can be performed for either primary lung tumors or metastases. The disease must be localized for successful treatment. The same precautions are taken for RFA of the lung.
RFA has been shown to be highly effective in treatment of a particular benign but painful bone tumor called osteoid osteoma. A bone biopsy needle is placed into this bone tumor and then RFA of the this tumor is completed. Pain is usually relieved within 6 weeks of treatment.
RFA is safe for most patients, and generally can be used in place of surgery for patients who cannot withstand longer surgical procedures, complications, and recovery times. Still, physicians will discuss the benefits and risks of RFA, and alternatives to this procedure, with patients in advance. The procedure usually will require some anesthesia. A medical history and blood tests may rule out some patients or require them to adjust certain medications. Also, some tumors or cancers are not considered treatable with RFA. The number and size of tumors that can be treated in a particular organ may be limited.
The patient lies on a table in an examination or surgical suite and becomes a sort of electrical circuit. The radiologist usually uses ultrasound, but sometimes computed tomography (CT) during the procedure to guide the needle placement into the tumor. Most interventional radiologists guide the small needle or probe that holds the current through the patient's skin and directly into the tumor. This is called the percutaneous method and will make for an easier recovery. Once the physician has positioned the tumor, the electrode delivers heat to a larger area.
The heat can be controlled by the physician. A small needle can accurately heat a precise area. If a tumor is large, the radiologist may have to guide and reposition the probe several times to destroy the entire tumor. After destroying the tumor, the physician also will use the probe to heat and destroy a small margin or rim of healthy tissue around the cancerous tumor. This helps ensure that no single cancerous cell is left behind that can regrow. After the treatment is completed, a small bandage is placed over the probe insertion site. Each RFA treatment takes 30 minutes, but the entire procedure can take longer, depending on the number of tumors, tumor size, and location. For instance, the radiologist may have to reposition the probe several times for one liver mass, then turn to a second smaller mass, increasing the procedure time.
Since some pain can be associated with RFA, most physicians will insert an intravenous (IV) line in the patient through which they will give anesthesia. However, general anesthesia which “puts the patient to sleep” is often used at our institution.
Before the RFA procedure, patients may have blood drawn for routine blood tests. The physician, nurse, or scheduler will provide preparation instructions that will include concerns about eating or drinking before the procedure. These instructions will depend on the type of anesthesia planned. Normally, patients will be told not to eat or drink eight hours (or after midnight) before the RFA procedure. Certain medications may need to be changed or stopped before the procedure. For example, blood thinners and aspirin may interfere with the procedure and usually must be stopped.
The treatment team will move the patient to a recovery room following the procedure to allow anesthesia to wear off and to receive pain medication as needed. Some patients also have nausea and will receive medications and instructions for nausea and pain care before leaving the facility. Patients will have to remain in bed for the first few hours following the procedure, and usually stay overnight from RFA.
Other Things to Expect
- Once the patient returns home, they should drink plenty of fluid.
- Mild pain may continue and may require prescription medication for the first day or two.
- Patients should not drive a car or make important decisions for 24 hours after the procedure because of anesthesia effects.
- Excessive physical activity is also discouraged. However, most patients can resume normal diet, physical activity, and sexual activity within a few days of RFA.
- Often the patient will be given an antibiotic to take by mouth for 5 days.
The risks associated with radiofrequency ablation are relatively minor compared to those associated with many other cancer treatments, particularly surgery. However, no procedure is risk-free. Some risks include:
- Serious injury if the needle makes a hole (perforates) a nearby organ. If this happens, the patient may require surgery to repair the injury.
- There also is a minor risk of infection at the site where the probe is inserted.
- Patients may experience bruising or bleeding. Bleeding could require transfusion or catheter embolization or surgery.
- If the lesion is in the liver and next to the diaphragm, this may cause pain in the abdomen or the right shoulder.
- There is risk of death from any procedure or from general anesthesia. The risk of death is in the range of 1 in 300.
Results vary, depending on the location, type, and size of tumor. Normally, scar tissue replaces the tumor cells destroyed by RFA and shrinks over a period of time. Patients should have no pain from the procedure after a few days. The patient will have a follow-up CT scan the day after the procedure and usually in 3 months.
- If pain continues for more than a few days, the patient should contact the physician.
- Some patients also develop flu-like symptoms and fever following RFA that can last for a few weeks. This may be normal. If the fever or flu-like symptoms are severe, then the patient should contact a physician.
- Bleeding after RFA has been reported. If it continues and is severe, the patient may have to return for an additional RFA procedure or surgery to control the bleeding.
- Sometimes, cancer recurs following RFA because tumors are so tiny they cannot be seen. Some patients will need another RFA procedure in the future.
- RFA of the lung or high liver lesions may cause a collapsed lung (pneumothorax) which could require insertion of a chest tube.
- For any concerns, the patient should contact the physician.
Section Chief: Ramit Lamba, MD