- Laparoscopic ultrasound finds...
- Doppler could become...
- Soft-copy sonography scores...
Laparoscopic ultrasound finds lesions CT misses
Technique augments but doesn't necessarily replace the surgeon's skill at palpation
By: Jane Anderson
Laparoscopic ultrasound (LUS) is better than CT at detecting liver tumors, especially smaller ones, according to a study published in the August Archives of Surgery. The finding opens the door for expanded use of the technique in a wide variety of surgical procedures.
LUS detected every tumor seen on preoperative CT and found nearly 10% that had been missed, said Dr. Allan Siperstein, head of endocrine surgery at the Cleveland Clinic Foundation.
"Patients were upstaged by the use of ultrasound," he said. "This study points out that intraoperative ultrasound is better than anything else for detecting lesions."
Siperstein and colleagues performed both CT scans and LUS on 55 patients with a total of 222 liver lesions, including both primary and metastatic liver tumors. Triphasic spiral CT scans were obtained less than one week before surgery. Liver LUS was performed with a linear 7.5-MHz side-viewing laparoscopic transducer.
LUS detected all 201 tumors seen on preoperative CT and detected 21 additional tumors (9.5%) in 11 patients (20%). The lesions missed by CT were broken down by size: more than a quarter were smaller than 1 cm and none were greater than 3 cm. CT was more likely to miss tumors in the falciform ligament of the liver and along the liver's periphery, according to Siperstein.
"The lesson here is to pay attention to everything, and obviously special attention should be paid to those areas where CT scan might be a little less effective," he said.
However, LUS should not replace preoperative imaging studies, according to the study. CT has proved its usefulness as a screening examination in patients at risk for hepatic malignant neoplasm, and both CT and MR are improving rapidly, with better image quality and the development of specific liver contrast agents.
Dr. Lawrence Wagman, who reviewed the research when it was presented earlier this year at the annual session of the Pacific Coast Surgical Association, had doubts, despite Siperstein's work.
"I'm not convinced that the gold standard is only intraoperative ultrasound and that the surgeon's hand can now be removed from this equation. It seems to me that in an analysis of this kind-imaging techniques without palpation-there needs to be a comparison with the palpation skill of the surgeon," he said.
Indeed, relying entirely on imaging is a potential weakness of the technique, according to Siperstein. But he says the study shows multiple opportunities for LUS to be used in a wide variety of other surgical procedures, such as those for colon cancer.
"If [the surgeons are] now doing a laparoscopic colon resection, they can also do a laparoscopic examination of the liver," he said.
This technique addresses a potential weak point of the colon procedure, which is not the actual colon surgery but the often-missed liver examination for staging purposes.
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Doppler could become stroke screening tool
Study of heart attack patients shows progression of disease decades before symptoms appear
By: Jane Lowers
The information obtained in high-resolution scanning of the carotid and brachial arteries could be an important predictor of heart attack risk. Researchers at Wake Forest University also say this data could help geneticists prove that risk for cardiac disease is sometimes passed from one generation to the next.
In a study of 80 patients aged six to 30, U.S. and Italian researchers found that patients whose parents had had early myocardial infarctions showed signs of higher risk for such events themselves. A marker-intima-media thickness of the carotid artery-has been found to be an independent predictor of MI and stroke, perhaps more powerful than traditional markers such as cholesterol.
"We hope that HCFA will recognize the significance of this marker and allow screening for asymptomatic disease," said co-author M. Gene Bond, Ph.D., director of vascular ultrasound research at Wake Forest. "Right now no one is doing that screening."
Bond and colleagues in the U.S. and in Naples tracked diameter and blood flow velocity in the brachial artery, using 7.5-MHz Doppler ultrasound, and calculated that artery's flow-mediated reactivity. They also used high-resolution B-mode scans to screen patients' carotid arteries to identify the greatest intima-media thickness, or the distance between the junction of the lumen and intima and that of the media and adventitia, with three measurements averaged for a mean score.
Patients whose parents had had a heart attack before age 60 had significantly lower brachial scores and significantly greater thickness in the carotid artery-both signs of atherosclerosis, according to the study, which was published in the Sept. 21 issue of the New England Journal of Medicine.
"The first implication is that the presence of atherosclerosis, as detected by B-mode ultrasound, is an independent predictor of risk that needs to be monitored," Bond said. "The second implication is that these patients were matched in age, cholesterol and triglyceride levels, and other traditional risk factors, yet the ones whose parents had had early heart attacks had more signs of atherosclerosis by an average age of 19. It doesn't prove anything, but it does suggest that there is an inheritable genetic influence at work here."
On a clinical level, the ultrasound scans may prove a better indicator of risk than such blood markers as apolipoprotein B, Bond said. They could also help physicians determine which patients known to be at risk for heart disease need immediate, heavy-duty intervention.
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Soft-copy sonography scores with efficiency
Pediatric imaging unit in St. Louis saves time and money even as its caseload grows
By: Jane Lowers
Moving ultrasound scans to soft-copy interpretation is saving a pediatric radiology department in St. Louis more than $100,000 a year. The move has reduced the reading burden of radiologists even as more patients with more images are examined.
Tracking the costs and savings generated since their department began converting to filmless operations in 1994, researchers at St. Louis Children's Hospital found that faster scan times allowed them to complete two extra scans per day, for an additional $112,000 in revenue in one year. Exam time decreased by 19%, according to data presented in the August issue of Pediatric Radiology. The same group, noting expected savings in printing and film and increased efficiency, predicted that it will save an additional $606,000 over the next five years.
Much of this efficiency can be attributed to the elimination of the double-sided, 12-image film cassettes technologists used to use, said Dr. Steven Don, an assistant professor at the Mallinckrodt Institute of Radiology.
The pediatric sonographers suspect they are spending less time keeping track of how many images are left and whether they are making the best possible use of their 12 exposures.
"Rather than getting six coronal and six sagittal images, for example, the sonographers are now free to choose whatever images they think best represent the case. It draws on their experience," he said. "One result is that they are taking a much greater number of images-one or two more per case-but that hasn't increased reading time because we end up with a more complete view."
In the reading room, the filmless system has saved radiologists hours by eliminating the hunt for old film and case jackets, which used to delay reports by as much as a day. Instead, the fairly rapid turnover of pediatric patients has meant that virtually all of the archives needed for patients have been stored digitally over the past few years and can be accessed immediately.
"Now that the films are available instantly, I can be done on time with the daily scans and the cases that come in from our portable scanners. At the end of the day I'm caught up and waiting for emergency cases," Don said.
Other conversions to filmless systems have produced similar gains. Moving a three-site radiology service to filmless for nearly all imaging saved more than $800,000 per year in personnel costs while allowing a doubling of productivity, according to Maryland researchers who presented their experience at the American Roentgen Ray Society meeting in May.
Three Veterans Administration sites in Maryland moved from film-based images to filmless in 1993 and 1994 and found that the added efficiency reduced the need for clerical staff, said Dr. Bruce Reiner, director of radiology research with the VA Maryland Health Care System.
The rapid turnaround prompted referring physicians to order more high-end scans, which contributed to a caseload that increased 100% in a year, from 25,000 in 1993 to 50,000 in 1994. In spite of the doubled volume, the Maryland VA department found that it could decrease its file room staff from 3.5 full-time equivalents in 1993 to one in 1995. Since the main department went filmless, it has added only half a radiology position and two technical positions, even though the case volume has increased about 10% per year since 1995. Satellite facilities have reduced their radiologist head count by two.
Adding up the total salaries for radiologists, technicians, and clerical staff, researchers estimate an annual savings of $882,000 strictly on salaries and benefits. At the same time, productivity stands at about 2500 cases per FTE per year for technicians, well above the national average of 2100.
The results aren't likely to be replicated exactly at other facilities, because tech support (Reiner's system has it included in the vendor contract) and other factors will vary, he said. Efficiency may also be influenced by the fact that the Maryland system is paperless as well as filmless.
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