Many emergency radiologists are abandoning contrast-enhanced plain films in favor of unenhanced spiral CT as a first-line diagnostic tool for acute abdominal pain. Detractors call this overkill, contending that radiography, ultrasound, intravenous urography, and time-honored clinical assessment offer sufficient information for diagnosis in most cases.

Two studies support the shift to spiral CT. In a series of 109 patients with flank pain at Stanford University, unenhanced spiral CT was 90% sensitive, 97% specific, and 94% accurate in detecting appendicitis (AJR 1996;160:763-766). In a Yale University study the modality was 95% sensitive, 98% specific, and 97% accurate in detecting ureteral obstructions (J Urol 1998;159[3]: 735-740).

The need for a definitive diagnostic test is well established. A landmark 1988 study by the World Organization of Gastroenterology of more than 10,000 cases of acute abdominal pain found that one-third never yielded a firm diagnosis.

“How to approach the patient with acute abdominal pain is a universal question,” said Dr. Robert E. Mindelzun, an associate professor of radiology at Stanford. “The best method is not obvious.”

Unenhanced CT’s main selling point is the lack of patient preparation required. It is quick, does not require knowledge of the patient’s renal function, and avoids the cost of contrast media. The technique is gaining popularity because it is effective and better than a clinical exam alone, which often leads to unnecessary surgery, said Dr. Michael J. Lane, section chief for body imaging at Brooke Army Medical Center and formerly at Stanford.

Ultrasound can be very good for diagnosing appendicitis, Lane said. It is operator-dependent, however, and limited by patient obesity. Patients with intense abdominal pain do not like transducers placed on them. Also, unenhanced CT’s ability to directly visualize stones makes it the gold standard in evaluating renal colic.

“Patients receive a diagnostic study without having to wait all day for intravenous urography,” Lane said. “Patients with suspected hemorrhage and diverticulitis are also easily detected with unenhanced spiral CT.”

Lane, however, is not zealous about avoiding contrast.

“I do give contrast to patients, but if I triage the patients effectively, the number of contrast cases is small. Thin or pediatric patients go to ultrasound, and nearly everyone else goes to unenhanced CT,” he said.

Speed is also a factor. A busy emergency department can image a patient in about five minutes, quickly freeing up the scanner for other patients, Lane said.

At Yale, radiologists administered roughly 2000 intravenous urograms and a handful of unenhanced spiral CTs in 1993. Today, the numbers are reversed. Radiologists conduct roughly 2000 unenhanced CTs a year and only a few hundred IV urograms.

The procedure does have its critics. No test should be conducted indiscriminately and unenhanced spiral CT may be overutilized in a number of applications, said Dr. Stephen Baker, a professor of radiology at New Jersey Medical School.

It is not a good test for diverticulitis because contrast is necessary to opacify the colon and ureter to find abscesses, Baker said. For pancreatitis, immediate imaging is not that important unless the condition is very severe. Only contrast CT can image pancreatic necrosis, and well-conducted abdominal x-rays can detect a pneumoperitoneum smaller than 1 cc, he noted.

As for appendicitis, spiral CT plays a second-string role to laboratory results, patient history, and clinical exams, which many doctors want before going to surgery, Baker said.

—By Dan Krotz

The cost-effectiveness of some imaging procedures is documented in the literature, but the knife can cut both ways. Research presented at a poster session of the American Society of Neuroradiology meeting calls into question guidelines for x-ray screening exams to check for the presence of foreign bodies in the eyes.

A group from Radiology Associates of Sacramento used a simple mathematical formula to calculate the cost of implementing the guidelines per quality-adjusted life year. The bottom line: The cost of implementing the screening guidelines is more than $2.2 million for each blind eye prevented and $75,000 per quality-adjusted year of life saved. The group recommended an alternative screening protocol.

“Clinical screening prior to radiologic screening would increase the cost-effectiveness of foreign body screening by an order of magnitude,” the group reported. “Simply asking the patient, ‘Did a doctor get it all out?’ accomplishes this goal.”

A screening program for peripheral vascular disease that’s intended to raise the profile of interventional radiology was initiated in September with a week-long pilot program at more than 100 hospitals in 10 communities. Depending on the results, the program may go nationwide next year.

Working with a public relations firm, the Society of Cardiovascular and Interventional Radiology alerted patients and physicians about the availability of PVD screening and the consequences of ignoring its symptoms.

“We want to educate everyone about PVD and let them know they have options,” said Tricia McClenny, assistant executive director of the SCVIR. “This could be a terrific way to raise awareness of the society. Members will be able to participate in an education and wellness program, and the community will learn that interventional radiology exists.”

PVD most often affects people over the age of 50. If it persists, loss of circulation can lead to amputation. And the risk of coronary death is 11 times higher among people with PVD. In its early stages, the disease can be treated with diet, exercise, and medication. More serious cases require interventional treatment via angioplasty or stents, thrombolytic therapy, or thrombectomy. The most serious cases must be treated surgically.

In the SCVIR screening program, patients answer a risk factor questionnaire and have their blood pressure measured at the ankle and arm. Good circulation and low vascular obstruction are indicated by a higher pressure in the ankle than in the arm. Those who show signs of obstruction are referred to primary-care physicians for evaluation.

Called “Legs for Life,” the program builds on the successful experiences of two interventional radiologists from the Pacific Northwest: Dr. Peter T. Beatty, director of cardiovascular and interventional radiology at Legacy Meridian Park Hospital in Portland, and Dr. Rod Raabe, director of angiography and interventional radiology at Sacred Heart Medical Center in Spokane.

The program targets primary-care physicians and patients; both groups are underinformed about the symptoms and consequences of peripheral vascular disease.

“Lots of people have the symptoms (of PVD) and often think they are something else,” Raabe said. “Ask people what it means if their legs hurt or cramp after walking a block or two. Most will say it’s arthritis or just getting old. It is uncommon for them to recognize the symptoms as vascular disease.”

Raabe recalls the case of a woman unable to walk across her kitchen without experiencing leg pain. She had seen six doctors over the course of seven years, and each had dismissed her complaints.

The final wish of her husband, who died of cancer, was that she find a cure for her leg pain. Finally, screening revealed PVD. The woman underwent surgery and is now fully recovered.

According to Beatty, about 10 million people in the U.S. have PVD and about half experience symptoms. Only about 10% are undergoing treatment.

“Interventionalists must educate primary-care physicians,” Beatty said. “They are overwhelmed. They may not know what a well-trained interventionalist can do.”

Raabe has screened about 500 patients per year in Spokane since 1994. He says that screening programs and the higher awareness of PVD have helped change practice styles.

“We used to have individualized care, but the screening program has made it much easier to coordinate care. We work closely with vascular surgeons and don’t have the turf wars that exist elsewhere in the country,” Raabe said. “Our angio lab is twice as busy as it was four years ago, and everyone is busier because PVD patients are getting the care they need.

—By John C. Hayes

Pediatricians may some day refer children with attention deficit disorder for MR spectroscopy to confirm the diagnosis before prescribing Ritalin or other forms of drug therapy.

Research presented at the annual meeting of the American Society of Neuroradiology shows that MRS is potentially useful for evaluating certain psychiatric disorders in children, including attention deficit hyperactivity, bipolar affective disorder, and autism.

Two of the studies were conducted by a team at the University of North Carolina. One showed increased levels of glutamate in children with bipolar affective disorder. The other found frontal lobe abnormalities in children with attention deficit hyperactivity disorder (ADHD).

A third study by researchers at the National Institutes of Health and Thomas Jefferson University measured elevated lipid peaks in at least one temporal lobe among children with autism.

All the studies used single-voxel proton MR spectroscopy.

“Attention deficit hyperactivity disorder has become very popular with parents,” said Dr. Mauricio Castillo, chief of neuroradiology at the University of North Carolina. “We have found that changes in spectroscopy point to some kind of biochemical or neurotransmitter disorder in the brains of these children. People who don’t have the disorder shouldn’t be treated just for the heck of it.”

The ADHD and bipolar studies evaluated frontoparietal regions of the brain. Peaks were determined for n-acetyl aspartate, choline, creatine, and glutamate in the bipolar study and for the same substances plus myoinositol in the ADHD study. The investigators also computed a variety of hemispheric ratios for the substances of interest.

The ADHD study involved seven patients and six age- and race-matched controls. The ADHD patients had higher ratios of n-acetyl aspartate/creatine, choline/creatine, and glutamate/creatine in the frontal lobes.

The bipolar study involved 10 children whose mean age was 8.4 years, and 10 age- and race-matched controls. It found higher glutamate levels in the right and left hemispheres of the bipolar children.

The autism study involved 10 children with clinical signs of the disorder. The primary finding was an elevation of lipid peaks in at least one temporal lobe, as compared to the occipital and parietal-occipital lobes.

“The findings suggest membrane turnover, indicating there might be ongoing seizure activity,” said Dr. A. P. Dagher, a staff radiologist at the NIH. “If seizures are involved, seizure medication might work in these patients. But we’re only documenting the end result. We don’t know what the cause is.”

MR spectroscopy appears to be carving out a niche in the evaluation of patients for whom conventional MRI provides inadequate diagnostic information, Castillo said.

“The real application of spectroscopy is in cases where MR imaging is normal, and we need to image the biochemistry of the brain,” he said.

Psychiatric disorders exhibit a significant biochemical overlap, which poses a diagnostic challenge, Castillo said. Identification of spectroscopic signatures for individual disorders would help minimize the overlap and better distinguish disorders that might have some features in common. Better recognition of the disorders should lead to better therapy.

Dagher is far less optimistic about MR spectroscopy’s potential in the evaluation of psychiatric disorders.

“The preliminary results suggest that MR spectroscopy does not seem to help much,” he said. “In the case of autism, we might have been looking at seizure activity rather than some other activity that could be responsible for other psychiatric disorders.

—By Charles Bankhead

Beginning in January, Medicare payments for radiology procedures will take a serious hit as the government takes another step in its drive to force down healthcare spending.

Organizations representing radiology—among them the American College of Radiology and the National Coalition for Quality Diagnostic Imaging Services (NCQDIS), a group representing diagnostic imaging centers—have campaigned to head off the fee cuts. Although the groups may yet win some minor victories, the fact remains is that under no reasonable scenario will radiology avoid reductions in Medicare payments.

By now, many radiologists have already heard the numbers. Under the Health Care Financing Administration proposal issued in June, overall Medicare payments for diagnostic and oncologic radiology would drop 13% over a four-year phase-in period.

The effect on patient care could be devastating, the ACR said in written comments to HCFA on Sept. 3.

“The increasing financial losses incurred under Medicare raise the issues of patient access to services and the quality of services they receive,” the ACR said. “Under the proposed rule, imaging radiation and therapy centers are estimated to take a 24% cut in their Medicare technical-component reimbursement. With cuts of this magnitude, our members report that they could not afford to remain in business. Additionally, physicians would be unable to afford modern radiologic equipment.”

The cuts come as part of HCFA’s plan to establish a new basis for valuing practice expenses, which are combined with work values and malpractice expenses to calculate Medicare payments. The new system for practice expenses is the final step in HCFA’s decade-long effort to replace historic “usual and customary” payments with a system that attempts to objectively evaluate the costs and value of all medical procedures.

Freestanding imaging centers, with their heavy reliance on expensive, high-technology equipment, may be especially vulnerable during this round of reforms. The law requires HCFA to use a sound methodology in determining medical practice expenses, and the agency struggled to find a solid source of information before finally turning to the AMA’s Socioeconomic Monitoring Survey. Both the ACR and the NCQDIS say the AMA survey seriously underestimates the cost of purchasing and maintaining imaging equipment.

For example, over half of the 174 diagnostic radiologists who responded to the AMA survey reported no equipment costs, and only 13.3% reported equipment costs of more than $25,000, according to the NCQDIS critique of the HCFA plan. Among the explanations for the low equipment cost figures: Cost data from non-hospital imaging facilities were specifically excluded from the AMA survey. Overall, providers who bill for technical costs under the Medicare fee schedule were underrepresented.

As a result, imaging centers would be paid only 12¢ on the dollar for their equipment, the NCQDIS said. The ACR maintains that equipment costs should be calculated at $23 per hour, nearly three times the amount HCFA plans to use.

Most of the ACR’s prescriptions for a fix come through revisions to the equipment cost calculations and a shift to a higher value CPT code as the basis for calculating the physician-time component of the fee schedule. The two changes would reduce four- year losses from 13% to 5%. The basic plan should be left intact, preserving relative values among diagnostic and oncology procedures, the ACRsaid.

The NCQDIS suggests other options, among them using NCQDIS-compiled survey data as a surrogate for the absent cost data from freestanding imaging centers.

Either way, radiology faces limiting its losses rather than preserving existing fees.

“We hope that over the four-year transition the proposed reductions in Medicare payments for capital-intensive diagnostic imaging services will be mitigated,” said Diane S. Millman, legal counsel for the NCQDIS.

—By John C. Hayes

Sonography is gaining support as a first-line exam in evaluating soft-tissue masses, with MR and CT reserved for problem-solving tools after ultrasound has confirmed the presence of a mass.

Although MR and CT have historically been considered superior for detecting soft-tissue masses, ultrasound’s high specificity has allowed it to move into this role, said Dr. Bruno D. Fornage, a professor of radiology at the University of Texas, M.D. Anderson Cancer Center, in an address at this year’s American Institute of Ultrasound in Medicine conference.

For example, high-resolution sonography can suggest the diagnosis of muscular rupture and hematoma. It can localize foreign bodies, such as wood lodged in the skin, and readily detect cysts, benign neoplasms, and hemangiomas. And real-time sonography is ideal for guiding needle biopsies of soft-tissue sarcomas. After excision, the modality is extremely sensitive in detecting early recurrence.

In one study, researchers at Thomas Jefferson University evaluated the ability of high-resolution sonography to localize superficial soft-tissue masses and guide needle biopsies of suspected recurrent malignancy (AJR 1998;169:1449-1451).

Twenty-four masses were localized and needle biopsied using 10-MHz sonography. Diagnostic information was obtained without complication from all 24 masses, and proved positive for recurrent disease in 13 of them. The researchers concluded that high-resolution sonography is a rapid, safe, and accurate way to localize masses and guide needle biopsies.

A big part of ultrasound’s gains are the result of higher transducer frequencies.

“Today, we have transducers at 10 to 13 MHz that give exquisite resolution. And the axial resolution of the transducer is better than that of MRI,” Fornage said.

Ultrasound is best at detecting masses no more than 6 cm below the skin’s surface. Beyond that, bone, and in the abdomen, bowel gas, cause too much artifact. But within the 6-cm range; ultrasound can scan minute lesions in real-time to guide needle biopsies.

A few years ago, MR’s superior resolution gave it an edge in evaluating small lesions. But with today’s transducers, radiologists can visualize nerves within structures just 3 or 4 mm in diameter, allowing the diagnosis of minute nerve sheath tumors, Fornage said.

Despite ultrasound’s merits, many referring physicians will still look to MR for making sense of soft-tissue masses, Fornage said. MR images seem easier to understand and can present a larger picture than ultrasound images. But ultrasound utilization will increase, not just in initial diagnosis, but in follow-up, he said.

“It is imperative to survey the tumor bed every six months with some form of imaging. And we found that there was no statistically significant difference between ultrasound and MRI in this application,” Fornage said. “We follow these patients with ultrasound, and if there is a problem, we refer to MRI, but most of the time ultrasound is sufficient as a first-line examination.

—By Dan Krotz

Scientists and surgeons at Yale University and the Massachusetts Institute of Technology (MIT) are taking ultrasound and telemedicine to new heights.

A well-publicized assault on Mt. Everest in May was the first of four expeditions that will help scientists understand the effects of extreme heat, cold, humidity, altitude, and water pressure on the human body.

Among their first findings: ultrasound imaging revealed that carotid arteries appeared larger in professional climbers than in novice climbers and that they dilate at higher altitudes so that the body can adapt to the thinner air. The findings could be important because scientists know that climbers at the upper reaches of Everest suffer various effects from the altitude, primarily oxygen deprivation to the brain.

Their equipment included personal status and vital signs monitors, specialized head-mounted cameras, notebook computers, and even a digital ultrasound imaging system designed for extreme environments, such as the battlefield. Data from the climbers were transmitted to base camp as radio signals through a satellite, under the Pacific Ocean via fiber-optic cables, and across the U.S. via telephone lines.

A video link was used to care for 65 climbers at the base camp, including an ultrasound examination of a Sherpa guide who complained of severe abdominal pains. What was thought initially might be a common duct stone turned out to be bowel gas, said Dr. Jim Brink, vice chairman of clinical affairs at Yale and an associate professor of radiology.

One problem associated with the ultrasound examination was patient resistance to disrobing at extremely low temperatures, Brink said. There also were problems with the gel freezing. Those problems aside, the Yale radiologists were able to remotely direct the position and sweep of the ultrasound detector.

“It is interesting to direct an exam remotely. It’s kind of like flying with the pilot directing you,” Brink said. “It was not ideal, but it worked.”

“It required a little bit of diplomacy,” he said. “Even though we could see each other, we had to appreciate how difficult the conditions are. We were sitting in a comfortable office while they were out in the freezing cold.

—By Kathy Kincade

Radionuclides essential to nuclear medicine procedures have been in erratic and short supply for years, but a proposal being pushed by the nuclear medicine community could assure a plentiful stock well into the future.

Several specialty groups, including the Society of Nuclear Medicine and the Council on Radionuclides and Radiopharmaceuticals (CORAR), are promoting a plan to combine production of medical radionuclides with generation of tritium, a helium isotope used in nuclear weapons. Industry representatives and physicians are lobbying Congress and the Department of Energy to approve the plan.

The proposal would tie radioisotope production to the government’s Accelerator Production of Tritium (APT) initiative to develop a new source of tritium, which decays rapidly and must be replaced in nuclear weapons every five years. Most of the nuclear medicine community appears united behind an APT facility proposed for a Savannah River site in Aiken, SC, where the DOE shut down a tritium production facility in 1988. Although the new facility would not be completed until 2007, many nuclear medicine advocates agree that it would be the best option for domestic, long-term, high-yield production of radiopharmaceuticals.

“If the Savannah River APT is chosen, we in the biochemical community will be very pleased,” said Dr. Henry Wagner, director of nuclear medicine at Johns Hopkins University. This accelerator facility is best suited for medical isotopes because of its size and adaptability, Wagner noted.

The biomedical community’s case for being included in the APT initiative rides on two assumptions. The first is that ancillary radionuclide production could be carried out without affecting tritium production, the primary APT mission; preliminary calculations show that secondary elements would require less than 2% of the accelerator’s proton beam. The second is that revenues generated from pharmaceutical sales would mitigate the high costs of running an APT facility for tritium alone.

While the medical isotope cause has been discussed within federal agencies and in Congress, and will be supported by South Carolina Senators Fritz Hollings and Strom Thurmond, the combined military and medical APT program faces a steep road to final approval.

“We are encouraging all of our members to write to their representatives and congressional delegations to make a clear case for nuclear medicine’s critical dependence on these materials,” said David Nichols, director of government relations for the SNM and the American College of Nuclear Physicians in Reston, VA.

The facility would furnish rare or unavailable radioisotopes in larger quantities than a reactor can. Promising advances may include development of more specific delivery agents, such as monoclonal antibodies, antibody fragments, and peptides, as well as new PET and nuclear cardiology procedures, according to a report issued in August by the DOE’s Los Alamos National Laboratory.

Radionuclides tentatively on the APT list are iridium-192, which is used in brachytherapy for inoperable tumors; strontium-89, used for bone cancer pain palliation; and iridium-111, used for infection diagnostics and systemic tumor therapy. Others include copper-67, germanium-68, palladium-103, rhenium-186, and samarium-153. The oldest and most common medical radioisotope, molybdenum-99, would probably not be included, even though 80% of the world’s supply comes from a single Canadian reactor.

Nuclear medicine advocates held workshops earlier this year to brief the biomedical sciences community on the radionuclide issue and promote awareness among legislators. Further meetings will occur in coming months. Decisions by Congress and the DOE are expected at the beginning of next year, but could come earlier.

The idea of uniting the medical and military missions was suggested by Sy Baron, a chemical engineer at the Medical University of SouthCarolina and former associate director of the DOE’s Brookhaven National Laboratory in New York.

“We want to achieve this synergy by substituting new linear accelerator technology for existing reactor production, which is an old and dying technology,” Baron said.

—By Josh Hough

MRI can simultaneously evaluate the brain, thorax, abdominal viscera, and the axial and appendicular skeleton in less than 20 minutes and serve as an alternative to bone scintigraphy for skeletal metastatic disease. This patient was imaged at Boston University by Dr. Richard E.A. Walker and Dr. Stephen J. Eustace with four overlapping coronal acquisitions using a body coil and a TURBO short tau inversion recovery sequence. Finding of bronchogenic carcinoma demonstrates a lobulated right hilar mass. Single high-signal focus in the right iliac (arrow) is consistent with marrow edema from a solitary bone metastasis.