Very few imaging spheres have witnessed as intense an interest in the past 2 years as has occurred with magnetic resonance angiography (MRA) technology. With the overcoming of initial concerns about the safety of MR contrast media,1 the imaging literature continues to grow with ever-wider applications of MRA methods for disease management. Here we consider several recent applications and discuss the cost-benefit of MRA in established applications.

Gadopentetate dimeglumine (Gd-DTPA) is the first contrast media approved (1988) for MR use in the United States, Japan, and Europe. It was initially approved for use in cranial and spinal MR but subsequently achieved whole body approval in Japan (1992), the United States (1993), Germany (1993), and other European countries. Additional approval exists for extracranial and extraspinal imaging to facilitate the visualization of lesions with abnormal vascularity in the head and neck. The most commonly used dose is 0.1 mmol/kg body weight. In many European countries marketing licenses have been granted for high dose applications (up to 0.3 mmol/kg body weight) and use in children and neonates (up to 0.2 mmol/kg body weight).

The use of MRA in discerning vascular disease in particular continues to expand, and now semiquantitative approaches have been developed to measure treatment outcomes by assessing luminal dimensions.2 Such approaches have the highest utility in the assessment of extracranial and intracranial disease, particularly in high-risk, asymptomatic patients.3 Carotid artery atherosclerosis is one of the most debilitating diseases and often presents with transient or small strokes, making clinical diagnosis problematic. Although US techniques can serve as useful screening studies, the gold standard for the evaluation of carotid disease remains arteriography. In many settings, MRA is beginning to replace arteriography, offering patients and their physicians an alternative to iodinated imaging. MRA is now also used to screen for aneurysms, arteriovenous malformations, and arterial or venous occlusive disease.

MRA of the abdomen and lower extremties. Photograph courtesy of Neil M. Rofsky, MD, director of MRI, Department of Radiology, Beth Israel Deaconess Medical Center, Boston.

The assessment of tumor response using MRA has been demonstrated in several settings including the head and neck.4 Imaging recurrent tumor and monitoring post-therapeutic changes may prove to be one of the best uses of MRA because of the diagnostic profile of MR contrast-enhanced imaging. This is already seen in uroradiologic procedures, which require exquisite accuracy and high resolution.5 MRA proves useful in guiding several interventional procedures including percutaneous access for nephrostolithotomy, antegrade pyelography with placement of a nephroureteral stent, and a diagnostic nephrostogram with exchange of a nephroureteral stent. Gd-DTPA flow is visualized fluoroscopically and produces excellent digital radiographs without allergic reaction or worsening renal function, obviating the need for iodinated contrast media.

Cost considerations

The cost-benefit of Gd-DTPA enhanced MRA in central nervous system and extracranial disease was recently investigated to determine whether it represented any advantages over CT-based management.6 Summary data were obtained for three managed health care plans representing low-level to concentrated management approaches (North Carolina, Connecticut, and California). A total of 3.6 million member months were reviewed for MRA utilization for suspected carotid artery disease. This was measured by reviewing health plan records grouped according to procedural coding descriptors. Procedural and related costs were assigned according to maximum 1999 Medicare allowable charges. Decision analytic models were formulated to identify short- and intermediate-term cost-beneficial disease management pathways. These models were used to predict downstream costs based on the accuracy of MRA-based versus CT-based patient management where arteriography served as the reference standard.

For the study, the diagnostic accuracy of Gd-DTPA enhanced MRA-based and contrast-enhanced CT-based management was quantitated and corresponded to values reported in the literature. This approach produced the total number of correct diagnoses as well as false-positive (FP) and false-negative (FN) rates. The total downstream cost per patient of FPs was $14,221 for MRA-based and $43,762 for CT-based management, respectively; the total downstream cost of FNs was $7,133 for MRA- based and $18,957 for CT-based management, respectively. The short-term procedural costs associated with MRA-based imaging were approximately 21.5 ? 14.1% lower than CT-based procedures. Other downstream savings are included according to diagnosis-related group (DRG) in the accompanying table.

Table. Reduced management cost associated with Gd-DTPA enhanced MRA.

The management of patients with suspected carotid artery disease based on MRA techniques results in lower downstream costs associated with diagnostic evaluation. MRA-based techniques offer overall improved clinical accuracy and fewer adverse events than CT-based options, which lowered downstream costs. Imaging information from MRA provides added diagnostic features that proved useful in guiding appropriate management, resulting in overall cost reduction.

The continued expansion of Gd-DTPA enhanced MRA technology rests on providing additional information of use to clinicians managing patients with central nervous system, vascular, and other disorders. This will serve as a means for establishing the utility of MRA techniques in a host of disease management paradigms and diagnostic algorithms. It is clear that the technical features of MRA continue to be optimized in the clinical as well as the investigative settings. It is also clear that the cost-effectiveness of Gd-DTPA enhanced MRA will soon be demonstrated in a variety of practice settings as the advantages of MR contrast enhancement begin to yield dividends that will drive savings to health care organizations.

Frank J. Papatheofanis, MD, PhD, is director, Advanced Medical Technology Assessment and Policy Program, Department of Radiology, University of California-San Diego, and a member of the Decisions in Axis Imaging News editorial advisory board.


  1. Shellock FG, Kanal E. Safety of magnetic resonance imaging contrast agents. J Magn Reson Imaging. 1999;3:477-84.
  2. Westenberg JJ, van der Geest RJ, Wasser MN, et al. Vessel diameter measurements in gadolinium contrast-enhanced three-dimensional MRA of peripheral arteries. Magn Reson Imaging. 2000;1:13-22.
  3. Wirestam R, Andersson L, Ostergaard L, et al. Assessment of regional cerebral blood flow by dynamic susceptibility contrast MRI using different deconvolution techniques. Magn Reson Med. 2000;5:691-700.
  4. Lell M, Baum U, Greess H, et al. Head and neck tumors: imaging recurrent tumor and post-therapeutic changes with CT and MRI. Eur J Radiol. 2000;3:239-47.
  5. Spinosa DJ, Angle JF, Hagspiel KD, Hartwell GD, Jenkins AD, Matsumoto AH. Interventional uroradiologic procedures performed using gadodiamide as an alternative to iodinated contrast material. Cardiovasc Intervent Radiol. 2000;1:72-5.
  6. Papatheofanis FJ, Smith R. MRA decreases downstream cost in carotid disease management. Radiology. In press.

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