From pediatric to adult patients, fluoroscopy continues to fill the real-time x-ray imaging needs of radiologists and surgeons. As conventional, portable and remote fluoroscopy systems either alone or in conjunction with other modalities expand the range of applications, the technologys evolution closes in on direct digital, flat-panel vascular imaging.
Meanwhile, lower doses of radiation are providing safer imaging environments for users and patients alike. As the next generation of equipment finds its way to the market, dose reductions will continue. Hospitals and imaging centers are calling on fluoroscopy to offer real-time viewing for common procedures, such as swallow, gastrointestinal and barium studies.
Patients also are benefiting from fluoroscopic studies that allow physicians to perform angiography, vertebroplasties and image-guided biopsies to name a few. Its versatility both alone and married to other modalities, such as CT and MRI, help ensure the modalitys viability. Although fluoroscopy has lost some of its studies to endoscopy and CT, the technology will be moving ahead, not away from the OR.
Angiography its intense
Fluoroscopy-guided angiography continues to garner attention. For children with uncontrollable hypertension who have had other more common causes eliminated, doctors at the Cincinnati Childrens Hospital Medical Center (Cincinnati) perform angiograms under fluoroscopy to determine whether narrowing in the renal artery is present.
[We perform these procedures] in a dedicated unit to do interventional procedures and angiograms; basically, the table can tilt, the image intensifier can go in all different angles to get different views of the patient, says John Racadio, M.D., chief of interventional radiology and assistant professor of pediatric radiology. With fluoroscopy, after weve gained access into the arterial systems, well put a catheter usually into the femoral artery down near the groin. Then under fluoroscopy, we can watch and manipulate our catheters into virtually any vessel in the body.
Without fluoroscopy, it would be impossible to know where the catheter is going. The interventional section performs approximately seven cases a day, which also include minimally invasive surgery and the placement of a peripheral intravenous central catheter (PICC) line, inserted in children that need long-term intravenous therapy, such as antibiotics. Traditionally, youd have to stay in the hospital, get an IV stuck in your arm [which] usually lasts for three to four days [after which] you have to get a new stick, Racadio says.
PICCs are long IVs that, once inserted in the arm, are advanced to the main artery just short of the heart. Fluoroscopy allows the nurse or doctor to confirm where the tip is. Once determined, the children can go home with the PICC lines inserted. Its a huge savings as far as getting children out of the hospital for intravenous therapy, Racadio says. They can go home and do home healthcare and get their antibiotics. The hospital does 900 PICC procedures per year.
After a quick fluoroscopic image to ensure proper positioning of the catheter tip (done immediately while the patient is there), an interventional radiologist can manipulate the positioning of the tip relatively quickly. The misplacing of a PICC can have deadly consequences.
The people who do [the PICC placement] without fluoroscopy like to say that 95 percent of the time they get their chest x-ray and its in perfect position, and the people prefer to do it under fluoroscopy say its at least 50 percent of the time the line [not placed under fluoroscopy] is in the wrong place, Racadio says. Thats why its nice to flash the fluoroscopy and manipulate the catheter position.
Racadio says that in studying more than 600 cases, they found the initial blind positioning of the catheter results in the need to reposition 78 percent of the time. Racadio and his colleagues presented data on the subject this fall.
Children also benefit from the combined use of digital fluoroscopy and ultrasound. Appendicitis is a common illness in children. When the appendix ruptures, the child can develop an abscess. The diagnosis is made with a CT scan. The interventional radiologists take the patient into the fluoroscopic suite, sedates him or her and with ultrasound guidance, gets a needle into the drainage catheter through the skin into the abscess.
Well use ultrasound to get a needle into the collection in the skin, and under fluoroscopy we advance through a small guide wire through the needle and see that under fluoroscopy, Racadio says. The guide wire advances into the patient and into the cavity.
The guide wire coils in the cavity. Over the guide wire, the physician can dilate a tract up through the skin and down into the abdomen. They insert a drain, and fluoroscopy is essential as a guide to determine where theyre going. The patient is left with a small drain through the skin. In some cases it completely avoids the need for surgery. In other cases it gets the children over the acute problem. Then they get antibiotic therapy and can undergo more of an elective surgery to remove the appendix, Racadio says. Its a lot safer procedure.
Fluoroscopy also is used to guide biopsies at Cincinnati Childrens Hospital. For a bony problem or bony lesion, Racadio says they biopsy either under fluoroscopy or CT.
Checking out the joint
For young patients with juvenile arthritis, arthrograms (injections of dye into joints) help diagnose the condition. Painful swelling and inflammation of joints require needle injections of steroids in joint spaces. [Rheumatologists] have seen how we do things with our image guidance, fluoroscopy guidance and our ultrasound, Racadio says. We can get into virtually any space in the joint, the foot, the elbow, wherever they might need to get steroids. If they do that without fluoroscopy, its pretty much a blind spot. You think you might be in a joint space, but there is not any way of knowing.
Doing the procedure under fluoroscopy confirms that the needle is in the joint, that the knee is affected that needs the steroids. Cincinnati Childrens Hospital has been doing the vast majority of the joint steroid injections for children with arthritis for the last two to three years under fluoroscopy. The hospital predominantly uses GE Medical Systems (GEMS of Waukesha, Wis.) digital fluoroscopy.
Texas Childrens Hospital (Houston) performs between 35 and 40 fluoroscopies per day. The majority of the procedures tend to be voiding cystourethrograms, which are performed in children with urinary tract infections or other abnormalities to determine if there is abnormal reflux of urine into the kidneys. Fluoroscopy also is used with contrast agents to examine the esophagus, the stomach and the small or large intestine.
Another study done almost exclusively in children is the speech study, Bruce Parker, M.D., says. These are children typically born with speech defects, anatomic defects such as cleft palate or lip deformity and who have very nasal speech. The child says a certain set of numbers and types of words, while the radiologist fluoroscopes the speech mechanism to be sure the childs tongue and palate are working properly.
Physicians at Texas Childrens Hospital also use fluoroscopy to examine the chest to determine whether or not a portion of the diaphragm is paralyzed. We can see whether or not it moves, Parker says. In children who have a habit of swallowing and sometimes aspirating foreign bodies, thats a very good way to determine if a child has an obstructed bronchus.
In the fluoroscopy arena, according to Parker, its not so much that new procedures are happening, but instead that the technology is improving. In any patient we have to be very sensitive to radiation dose, Parker says. We try to keep it to a minimum. Obviously, keeping the time of fluoroscopy down is important, and we strive to do that but technological advances have helped us a great deal. The different types of radiation detectors that we use are more sensitive, so we use less radiation.
Texas Childrens uses pulsed fluoroscopy, which allows the radiologist to set the frequency of pulses thus reducing the radiation dose as much as a third of the fairly standard fluoroscopy. The hospital is gradually replacing its standard fluoroscopes with pulsed fluoroscopy.
The hospital has four fluoroscopy rooms that run from 8 to 5 daily. Philips Medical Systems (Bothell, Wash.) provides its standard fluoroscopy systems. Siemens Medical Solutions (Iselin, N.J.) is the hospitals multipurpose fluoroscopy vendor.
Not just for kids
As adults continue to live longer, fluoroscopy is helping them raise their quality of life. For older people with osteoporosis and those suffering back fractures often because they are active and still relatively healthy fluoroscopy provides real-time imaging during vertebroplasties.
Mercy Medical Center (Baltimore) performs one to two of these procedures weekly on patients whose vertebral bodies can collapse from osteoporosis. R. Anthony Lloyd II, M.D., director of neuroradiology, says vetebroplasties are made simple by fluoroscopy.
We place a needle under fluoroscopy guidance into the bone that is fractured and hurt, Lloyd says. [We then] mix some liquid cement that turns hard in about 20 minutes. We inject this into the body and try to fill it. By filling it, we reinforce it and augment it so it doesnt fracture down anymore. This almost heals their back pain before they leave [the hospital]. They can move around and get active again. We do [vertebroplasty] only by fluoroscopy.
The only known fatalities resulting from the procedure that Lloyd says they are aware of were done without fluoroscopy, resulting in the cement backing into the canal and veins, taking cement to the lungs. The result was infarct and blocked lungs vessels. Without fluoroscopy, physicians cannot watch the cement being extruded into the bone in real time.
When doing the vertebroplasty, one view is taken of the back to look at the canal of the bone. When clinicians do angiograms of the head, they sometimes find aneurysms. One view will not show that. I like to see the neck, Lloyd says. We have a rotational fluoroscope machine. It goes around and takes pictures almost like a CT scan goes around the body, which is very helpful and gives you a 3D look.
At Diagnostic Radiology Consultants (Chattanooga, Tenn. and Fort Oglethorpe, Ga.), Joseph Busch, M.D. and his colleagues use Siemens remote fluoroscopy technology. They made the switch from conventional fluoroscopy to remote about 10 years ago after comparing the European practice of remote to Americas conventional fluoroscopy.
This added a certain efficiency of practice, and by that I mean you could execute barium studies as well as routine urinary tract studies and radiographic studies faster than in a conventional R&F room, Busch says. So you could do more with less space and fewer people in a shorter time. All that translates to efficiency.
The group has three different fluoroscopy sites, in which they do outpatient and inpatient fluoroscopy. They average approximately 40 procedures a day. When they switched from analog 10 years ago, each study was performed on an all-digital file. There were no analog sets in the room, Busch says. We operated with a digital fluoroscope or what we would call today in a sense direct acquisition.
The intensifier went from 16 inches to six inches, allowing for kidney, bladder and esophagus imaging, as well as shooting an entire pelvis. This lends itself to what I term rapid fire practice, Busch says. You can move the patient in and out and at the same time we dictated from the machine off the digital image on the screen. Therefore we eliminated the old process of hanging the films and viewing the cases later in the morning. Consequently it freed us up to do more things faster, so we were a more efficient practice because of this I would strongly say that nobody [here] would go back to conventional.
The extreme age ranges can be difficult to image with fluoroscopy, but the next generation of technology should make the process easier and safer. With kids you have a moving target, and you want to keep the radiation down, David Ball, D.O. at St. Lukes Hospital and Health Network (Bethlehem, Pa.). There is not a lot of body mass, so it is easy to over-penetrate with fluoroscopy. With the next generation [of equipment], [imaging] should be a lot easier. [Its] the same with the elderly who can be disoriented. If we can image them more reliably and quicker, it can be a less bewildering experience.
St. Lukes uses GE Medical Systems fixed equipment and GE OEC (Salt Lake City) C-arm systems to do digital fluoroscopy. I think lower doses will continue over time as the next generation of equipment becomes available, Ball says. With the next generation, we should see a 30 to 40 percent reduction, which means less dose for the technologist, the operator and patient over time.
Digital flat-panel detectors comprise the next generation of fluoroscopy technology. Inherent in that technology will be the improved ability to view greater detail of the anatomy and pathology. It will provide sharper vision. It also will allow for the use of smaller catheters and smaller wires for interventional procedures, while decreasing the radiation dose.
The current image intensifiers weigh several hundred pounds and interfere with your ability to get close to the patient. In an emergency situation where seconds count, things like that could be critical, Ball says. Whereas, [the next generation of equipment] may allow us to get new types of angulations and different ways to see things because of their thinner profile and their overall smaller bulk.
The elimination of the analog-to-digital conversion by digital flat-panel technology also will eliminate artifacts and deliver better data processing with lower chances for error. Ball says it will be less complicated in the long run and more dependable.
The equipment will have more up time, Ball says. Our overall equipment has great uptime now, but it will have even more [with flat panel] because when you have a simplified imaging chain, there are fewer things to break. Every year or two you lose five days involving an [analog to digital] converter or image intensifier. Youd be picking up at least part of that in terms of work load and need for people. Ball expects that once referring physicians see the images, overall referral volume will increase.
When it comes to cost, which many balk at, Ball draws a parallel between imaging system prices and the more general computer market. [According to] Moores Law, in computing youre going to double your computing power every 18 months, and at the same point in time, youre going to keep the cost the same or drop that in half over time, Ball says. So every 18 to 36 months, youre going to be able to buy a computer thats four times more powerful than what you had 2 to 3 years ago. Knowing that… people probably replace their computers every 3 to 4 years. Are they getting much more in return? Not necessarily. They are getting something faster. And what that has to do with the way imaging is acquired is that currently you have a digital system and you have to convert analog to digital information. With the newer system, it will be direct digital acquisition, which means everything will be faster.
In addition, it will be a lower radiation dose x-ray, quicker acquisition, and simpler processing and fewer errors in the way the image is processed.
St. Lukes currently does 5 to 10 gastrointestinal studies and 15 to 20 interventional studies per day using fluoroscopy.
GEs flat-panel detector for vascular work remains a works in progress. The company does market its Innova product, which is its digital flat-panel cath lab, introduced two years ago.
We do have digital fluoroscopy used for vascular work on our traditional imaging intensifier system, Linda Olsen, marketing representative for GE OEC says. [And] we have shown images [at the American College of Cardiology and the Radiological Society of North America] for vascular angiography taken from a flat panel, so it is coming.
Vascular flat-panel technology will be a revolutionary announcement when it comes, according to Olsen, because of the size of the market. Peripheral vascular work and associated diseases are a large issue. Flat panel will make a remarkable impact there, but also on stroke intervention, Olsen says.
GE Medical Systems OEC offers a 1K x 1K mobile fluoroscopic digital imaging interventional and surgical imaging system, the OEC 9800 Plus. The company says the system can image clearly in areas between high and low density and in patients that have metal implant devices. Features on the system enable the user to adjust the quality of the fluoroscopic image for the metal object and retain image quality.
As fluoroscopy retains its place in hospitals and imaging centers around the country, everyone waits to see if digital will fulfill its promise. Fluroscopys achievements continue to gain recognition and its share of champions.
[Theyve] made fluoroscopy live, quick, less radiation to the patient and doctor; its digital so it can be transported over lines instead of films that would need [manual] transporting, Mercy Medical Centers Lloyd says. The only thing to do in the future is to continue to decrease the radiation dose and [create] sharper images. Its doing a great job.