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IMAGES FROM PHILIPS MEDICAL SYSTEMS.
TOP: An en face view of child’s mitral and tricuspid valves revealed critical pulmonic stenosis.
BOTTOM: Live 3D Echo allowed surgeon to see the anatomic detail of child’s double orifice mitral valve from multiple angles.

Before, during, and after surgery, ultrasound continues to win over users. Specialists offer resounding support for the modality that is meeting surgical needs by offering critical imaging information, as well as smaller units, better pricing, and improved quality.

Ultrasound’s applications in conjunction with surgery run the gamut: liver, heart, breast, neck, and more. Incorporating ultrasound for better staging of cancer, intraoperative transesophageal echo (TEE) to help prevent stroke in cardiac patients, and image guidance for catheter positioning in atrial fibrillation procedures has surgeons, cardiologists, radiologists, and anesthesiologists who use the technology sharing one realization: They would not want to do their work any other way.

Laparoscopic Ultrasound
Raymond Onders, MD, director of minimally invasive surgery at University Hospitals of Cleveland (Cleveland, Ohio) and assistant professor of surgery at Case Western Reserve University (Cleveland), uses ultrasound in approximately one third of the operations he performs. Laparoscopic ultrasonography replaces cholangiography for assessing the common bile duct in the liver.

“I use it for assessment of malignancies, when we’re doing staging laparoscopies,” Onders says. “We use a high-frequency ultrasound probe so you can actually place one in one of our laparoscopic cords to look at the liver and at the lymph nodes inside the abdomen to make sure there are not any malignancies.” Onders also uses ultrasound while doing an adrenalectomy to see if the adrenal gland is invading other structures.

Previously, surgeons would shoot cholangiograms using x-ray, which required more expensive equipment and the skill of a radiologic technologist. Using ultrasound is more rapid, eliminates the need to bring in other people to do the procedure, and provides sensitivity that is “just as good if not better than doing the cholangiography,” according to Onders. In his practice, Onders performs approximately 200 cases per year involving laparoscopic ultrasound in the OR.

“With the advent of laparoscopy, which took off 10 or 12 years ago, during surgery you can’t touch [an area] with your own hand, [so] ultrasound becomes your ability to feel structures inside the abdomen,” Onders says. “You wouldn’t need ultrasound if you could put your hand inside someone and palpate for something, but you can’t do that, so ultrasound becomes a necessary part of staging for malignancy.”

The laparoscopy provides a two-dimensional image, even though you are operating in three dimensions. By adding the ultrasound probe, a surgeon can see the third dimension. “Part of the reason I started doing so much ultrasound is because of laparoscopy,” Onders says.

The probes currently are 10 mm in diameter, but Onders would like to see the size reduced by half to increase ease of use for insertion into the abdomen or the operative field.

Some gastroenterologists and surgeons are using endoscopic ultrasound to see more than the surface of the stomach or the colon. “With ultrasound, you get to look through that and see how big the lesion is, where it’s invading,” Onders says. “That has become almost standard for [staging] rectal cancers and for most GI tumors for the stomach, esophagus, or pancreas before the operation to get better staging.” Onders uses B-K Medical (Copenhagen, Denmark) ultrasound technology.

Trauma units increasingly are using ultrasound to do very rapid assessment to determine if fluid is present in the abdomen. The presence of fluid could be a sign that a patient should go immediately to the operating room. The examination usually includes looking for several spots in the abdomen, as well as in the heart, for damage. Next the patient is stabilized and then goes for a computed tomography (CT) scan to provide further information.

At the University of Pennsylvania Health System (Philadelphia), the major reasons Steven Horii, MD, professor of radiology at the University of Pennsylvania School of Medicine (Philadelphia), and his colleagues are called for intraoperative ultrasound procedures is evaluation of the liver. They also image the neck in patients with parathyroid tumors. The parathyroid gland regulates calcium metabolism. People with parathyroid tumors have a lot of kidney stones and high blood calcium. Occasionally, surgeons will get in the neck and be unable to find the parathyroid. In those cases, they may ask for ultrasound to help locate the gland.

The patients have had CT and MR scans, but some liver patients may be several months before they get to surgery, so the question becomes: Is anything else in the liver that was missed—and does the surgical plan need to be changed?

“If we find multiple liver lesions, the patient no longer is a candidate for trying to achieve disease-free status by removing the metastatic lesion,” Horii says. “He or she already has widespread lesions, and they’re going to change the surgical plan to probably placing chemotherapy appliances, rather than trying to resect all the masses.”

The other objective is to map out the anatomic relationship of the mass to the rest of the liver, particularly the blood supply. The relationship between the mass and the hepatic veins and portal vein system can affect the surgical approach as well.

“Some of that they will know from the preoperative CTs and MRs, but the nice advantage of real-time ultrasound is I can scan in almost any plane so that the relationship of the mass to normal anatomy becomes more clear,” Horii says. “Prior to this, they relied on the CTs and MRs. Surgeons would look at those and say they think it is a thing they can get out, and they would [remove] it. They would occasionally get unpleasant surprises.”

 Multislice CT with its good spatial resolution and MRI with its ability to pick up contrast between different kinds of tissue offer certain imaging benefits. However, once you get into the operating room environment and are able to do ultrasound scans directly on top of the liver itself, the spatial resolution starts to approach that of CT. In addition, no lag time exists between doing the studies and the surgeon’s seeing the results. Horii uses Philips ultrasound equipment and performs three to four cases a week using intraoperative ultrasound. That number has risen from one per month.

Urologists doing nephrectomies also use ultrasound when trying to decide whether to remove the entire kidney or try to wedge out a tumor. “A lot of that depends on whether we tell them the tumor has extended into certain parts of the kidney or not,” Horii says. “[What] we do tends to affect the surgical plan.”

Ultrasound has rapidly become a part of general surgery. In Europe, all surgeons train in ultrasound during their residency. Ease of use and better pricing have helped move the modality forward, and ultrasound continues to become more prevalent in offices and other areas outside of hospitals.

“The American College of Surgeons (Chicago) saw this coming around 5 or 6 years ago, so they began a very exact training program for surgeons who haven’t been trained in ultrasound before,” Onders says. “They have a very in-depth training program. Surgeons who are certified instructors teach the classes.” The society holds courses several times a year throughout the United States.

Diagnosis and Intervention
Breast surgeons routinely use ultrasound for diagnostic workups of patients who will undergo image-guided needle biopsies to localize lesions for biopsy or lumpectomy and for balloon catheter placement in the lumpectomy area for delivery of accelerated partial breast irradiation.

Both surgeons and radiologists do image-guided breast biopsy with ultrasound. “The patient has an abnormality that shows up on a mammogram and also can be visualized by ultrasound or [has] something on a physical exam that can be visualized as a discreet lesion on ultrasound, then under local anesthetic a needle device can be used to obtain a diagnosis of the lesion prior to the patient [going] to surgery,” says Richard Fine, MD, president of the American Society of Breast Surgeons (ASBS of Columbia, Md) and codirector of The Breast Center (Marietta, Ga).

“If the patient has benign disease and that’s proven with an image-guided breast biopsy, they can avoid having an open surgical biopsy,” Fine says. “So we’ve been able to eliminate about three quarters of the women who have needed to go to surgery to find out that they do not have breast cancer.”

If a patient has to go to the operating room for a proven cancer or for something that is precancerous that requires an open surgical incision or lumpectomy, ultrasound can be used to localize the lesion for the biopsy or lumpectomy. Following a lumpectomy, ultrasound also can be used to ensure the presence of clear margins of breast tissue around the area of tumor removal.

“It can be used in two different ways for localization: Either you place a wire under ultrasound or you can use intraoperative ultrasound, [putting] the ultrasound transducer in a sterile camera tray to scan in a sterile field and mark out the boundaries of the abnormality that is trying to be removed,” Fine says.

For localization, if a patient has an image-guided breast biopsy as an out-patient, a clip or marker can be left behind where the biopsy was performed. Some of these markers are visible via ultrasound.

Using a MammoSite balloon catheter by Proxima Therapeutics Inc (Alpharetta, Ga), Fine also performs accelerated partial breast irradiation with ultrasound guidance to place the catheter in the lumpectomy area for delivery of radiation treatment over a 5-day period. The procedure eliminates the need for a 6-week period of radiation for the patient. Fine uses B-K Medical’s Merlin, an office-based machine designed for small parts and breast ultrasound, and the Leopard ultrasound machines.

 Radiologist Steven Horii, MD, professor of radiology at the University of Pennsylvania School of Medicine, points out a spinal abnormality on an ultrasound image. Horii often performs intraoperative ultrasound procedures to evaluate the liver as well as locate the parathyroid gland.

Prior to the use of ultrasound for breast procedures, if a patient had something that was found on a physical examination or mammogram and needed to find out if it was cancer, it meant a trip to the OR for an open surgical biopsy. “Out of all those patients who went for surgery, only 20% had cancer, so four out of five biopsies turned out to be benign,” Fine says. “But by doing these image-guided breast biopsies, we were able to eliminate 75% to 80% of patients who before had to go to the operating room to find out if they had cancer. Medicare data from 1998 said that only 22% of all biopsies were being done with image-guided biopsy, and 78% were being done with surgery.”

Currently, some estimate that image-guided breast biopsy is being done as frequently as 60% of the time. “[There are] still areas of the country where patients are not offered image-guided breast biopsy, and one of the reasons is that there are unfortunate situations that exist in physician reimbursement where physicians are not reimbursed to cover the cost of doing image-guided breast biopsy,” Fine says. “That’s one of the limiting factors.”

Some progress on the reimbursement front has occurred, including obtaining a CPT code for vacuum-assisted needle biopsy. “The code eventually came out with a reimbursement in the office setting that did cover the cost of the disposables, so that was [an] improvement,” Fine says.

One of the unfavorable things about the new codes is the disconnect with improving technology. Companies are trying to create better biopsy devices for women, and some of the technology actually may move into the therapeutic realm, enabling removal of a cancer, for example, by a small opening using a special device. “The problem is that the code is not going to cover the cost of increased technology, and we have to start looking at more codes to cover the types of devices that would be more beneficial to women,” Fine says.

The Breast Center performs approximately 600 image-guided biopsies per year and sees 3,200 patients annually.

Fine says the American Society of Breast Surgeons has an established certification program to ensure the quality of ultrasound scans for women.

TEE and epiaortic scans
Cardiac and thoracic surgery patients are benefiting from transesophageal echocardiography (TEE) that monitors cardiac function and epiaortic scanning, in which a high-frequency surface probe is inserted into the surgical field after the chest is opened and the ascending aorta is closed. The scan looks for atherosclerosis.

Jack Shanewise, MD, associate professor of anesthesiology and director of cardiac and thoracic anesthesiology at Emory University School of Medicine (Atlanta), sees epiaortic scanning as an area with increased importance. “This is done as a strategy to try to reduce strokes in patients who are having cardiac surgery,” Shanewise says. “A very important cause of strokes in patients who are having heart surgery is an atheroembolism to the cerebral arteries from atherosclerosis in the ascending aorta, due to the manipulation of the ascending aorta that patients have in heart surgery, the clamping of the aorta, and the cannulating of the aorta.”

 Philips medical system SONOS 5500

Ultrasound scanning identifies patients who have atherosclerosis in their ascending aorta, and then the surgeons can modify their techniques to avoid manipulating those areas. “Our surgeons are convinced that it’s helpful, but I think it’s not widely known or applied; [however,] there is increasing awareness of it,” Shanewise says.

The use of TEE is increasing and expanding into noncardiac surgery. “We’re seeing it used more to monitor cardiac function in patients who are having things like major aortic surgery, aortic aneurysm surgery, or liver transplant surgery, or in any case where there can be major hemodynamic changes,” Shanewise says. The TEE probe watches the cardiac function, including the left and right ventricles, assesses the volume status of the cardiovascular system, and looks at valves —all in real time.

“In the operating room, it can be used to monitor myocardial ischemia during surgery,” Shanewise says. “Typically we take that at the end of the operation.” Shanewise uses Philips’ Sonos 5500 system.

Surface probes on the neck also assist in placing vascular cannula. Ultrasound identifies the location of the internal jugular vein to assist when placing central venous catheters. “That’s been around for a few years, but there is increasing awareness of it,” Shanewise says.

Real-time 3D imaging for TEE remains on Shanewise’s wish list for the modality. “The limitation right now is size. We need to have smaller transducers than you have for surface echocardiography because they are going in the patient’s esophagus,” Shanewise says. “The other thing that we’re trying to work out and still have a [way to go] is using ultrasound contrast agents to image perfusion in the myocardium. There’s been great[er] success with that in surface echocardiography than with TEE echocardiography. It would be helpful if we could use echocardiography to determine whether or not a region of the myocardium was perfused using contrast agents.”

Children’s hearts
Pediatric patients continue to benefit from the use of TEE for almost all surgical procedures at the University of Chicago’s Children’s Hospital. The facility utilizes TEE preoperatively to assess a patient’s cardiac anatomy and function to provide the surgeon with a clear idea of what he is going to see once the chest is opened and after the bypass.

“[We] assess the result of the surgical procedure to look at any residual cardiac defect, to [check] cardiac function, and to help the surgeon decide whether this patient needs certain medications or needs to go back and bypass to fix whatever . . . residual defect [is] left from the operation,” says Zihad Hijazi, MD, professor of pediatrics and medicine and chief of pediatric cardiology.

Hijazi and his colleagues also use cardiac imaging in the cardiac catheterization laboratory. “We have some procedures we do under intracardiac echo (ICE) using the ultrasound machine or transesophageal echo similarly to assist the cardiac anatomy and cardiac function, and, more important, to guide the closure process should we need to do a closure of a cardiac defect or placement of a coil or a device, balloons, or stents,” Hijazi says.

Intracardiac echo is replacing TEE in the cath lab, and more than 99% has been replaced in the last 2 to 3 years. “By doing that, we don’t need anesthesia,” Hijazi says. “We give only mild sedation and local anesthesia. We still use TEE in certain circumstances if the baby is very small for the intracardiac echo or if there is a need to close a ventricular septal defect. Yet, for atrial septal defect or patent foramen ovale, for the most part, intracardiac echo has replaced TEE completely.”

Ablation procedures
Ultrasound also has become an important part of atrial fibrillation ablation procedures in positioning the catheter and ensuring the surgeon is at the opening of the pulmonary vein, and for titration of power to ensure not too much or too little is used. “We look at tissue changes or at microbubbles generation,” says Andrea Natale, MD, co-head of the Section of Pacing and Electrophysiology and medical director of the Center for Atrial Fibrillation at the Cleveland Clinic Foundation (Cleveland, Ohio). Titrating power with intracardiac echo helps in preventing pulmonary vein stenosis, which is one of the complications associated with the ablation procedure for atrial fibrillation.

“Probably one of the reasons for the reduction in pulmonary stenosis is we do a better job in titrating power, so we are not using too much, [resulting] in less destruction of the atrial wall and the lining of the atrium, which is the effect responsible for less pulmonary vein stenosis,” Natale says. “We do about 10 or 15 procedures a week with the intracardiac echo.” Natale and colleagues also use intracardiac echo for a form of ventricular tachycardia where the ablation is to be done very close to the coronary artery.”

ICE ensures that the catheter is not directly on top of the coronary artery and that it does not move during the ablation, helping to avoid major complications. “If you’re not careful and do not know where you are when you are ablating close to the coronary artery, you can close the coronary artery and cause a massive heart attack,” Natale says. “The coronary artery supplies the heart muscle with oxygen. It is important to stay away from there.”

Using ICE with the closure device to close a hole between the two upper chambers, atrial septal defect (ASD), and patent foramen ovale (PFO) is especially appealing to patients who have experienced the discomfort of TEE previously. “It is good for the physician because it eliminates the need for general anesthesia, makes the procedure and the recovery of the patient shorter, and potentially reduces the chance of some complication that might happen as a result of the general anesthesia,” Natale says.

Imaging will play an important role in the future of ablation. “If the technology can be improved, it can move into a 3D-type of imaging, it will continue to grow, and it will be accepted more and more,” Natale says. The other improvement that Natale hopes for is image quality, “so we can see even better than we can now [without] a problem in anybody [with a thick septum].

With high-quality training for users, equipment that is priced within the doctors’ reach, and ongoing improvements in image quality and size of the probes, ultrasound will continue to be incorporated into increasing numbers of surgical decisions. Sounds like a plan.