MRA detects stenoses in nether arteries
MRA detects stenoses in nether arteries
Tue, 13 Mar 2001 21:00:00
Amsterdam, the Netherlands - Magnetic resonance angiography (MRA) is highly accurate in assessing arterial disease in the lower extremities, according to a meta-analysis published in the March 14, 2001 issue of JAMA.
Dr Mark J W Koelemay and colleagues (Academic Medical Center, Amsterdam, the Netherlands) undertook an extensive literature review of all studies on MRA published between January 1985 and May 2000 so that they could get a good estimate of the diagnostic accuracy of this "rapidly evolving" noninvasive technology in diagnosing occlusive disease in the lower extremity arterial tree.
MRA may one day replace arteriography as the imaging standard
The standard technique for assessing arterial disease in the lower extremities has been arteriography, but its use over the past 10 years has been on the wane, thanks to the development of noninvasive imaging techniques, such as color Duplex ultrasonography and MRA. Although it is still considered the reference standard, arteriography's accuracy in depicting the infrapopliteal arteries is limited. If MRA were found to be reliably superior in assessing these vessels, it could supplant arteriography as the imaging standard before distal bypass surgery, the authors write.
Koelemay and his group scruitinized 34 of 3583 studies identified from MEDLINE, EMBASE, and Current Contents databases. Studies included in their meta-analysis compared MRA with conventional arteriography (CA) or intra-arterial digital subtraction angiography (iaDSA) for detection of > 50% stenosis or occlusion in patients with claudication or critical limb ischemia. The median sample size of the 34 studies was 25 patients and overall, 1090 patients, most of whom had claudication, were assessed with MRA.
The authors report that MRA proved to be highly accurate in the assessment of all lower extremity arteries. Three-dimensional gadolinium-enhanced (3-D Gd) MRA was better at diagnosing arterial disease than two-dimensional MRA.
You've come a long way, baby
The studies included in this meta-analysis were all published within the past 8 years, during which time MRA techniques have changed significantly, Koelemay et al point out.
"Image acquisition time has been reduced from more than 1 hour to a few minutes; susceptibility to flow artifacts and image quality have been improved by electrocardiogram triggering, gadolinium contrast, and subtraction techniques. Moreover, the value of new contrast agents or MR sequences has not yet been tested in comparative studies. These innovations suggest that MRA techniques and their definitive role in clinical practice are still evolving."
The authors also add that little is known about the value of MRA in improved clinical outcomes. They note that the patients who derive most benefit from percutaneous interventions are those with critical limb ischemia, not claudication, and most of the patients in their meta-analysis had claudication.
Although the quality of studies with MRA has improved over the years, Koelemay et al say the studies can be made even better. The researchers call for standardization of both study designs and reporting of results to facilitate the dissemination of MRA technology.
Amsterdam, the Netherlands - Magnetic resonance angiography (MRA) is highly accurate in assessing arterial disease in the lower extremities, according to a meta-analysis published in the March 14, 2001 issue of JAMA.
Dr Mark J W Koelemay and colleagues (Academic Medical Center, Amsterdam, the Netherlands) undertook an extensive literature review of all studies on MRA published between January 1985 and May 2000 so that they could get a good estimate of the diagnostic accuracy of this "rapidly evolving" noninvasive technology in diagnosing occlusive disease in the lower extremity arterial tree.
MRA may one day replace arteriography as the imaging standard
The standard technique for assessing arterial disease in the lower extremities has been arteriography, but its use over the past 10 years has been on the wane, thanks to the development of noninvasive imaging techniques, such as color Duplex ultrasonography and MRA. Although it is still considered the reference standard, arteriography's accuracy in depicting the infrapopliteal arteries is limited. If MRA were found to be reliably superior in assessing these vessels, it could supplant arteriography as the imaging standard before distal bypass surgery, the authors write.
Koelemay and his group scruitinized 34 of 3583 studies identified from MEDLINE, EMBASE, and Current Contents databases. Studies included in their meta-analysis compared MRA with conventional arteriography (CA) or intra-arterial digital subtraction angiography (iaDSA) for detection of > 50% stenosis or occlusion in patients with claudication or critical limb ischemia. The median sample size of the 34 studies was 25 patients and overall, 1090 patients, most of whom had claudication, were assessed with MRA.
The authors report that MRA proved to be highly accurate in the assessment of all lower extremity arteries. Three-dimensional gadolinium-enhanced (3-D Gd) MRA was better at diagnosing arterial disease than two-dimensional MRA.
You've come a long way, baby
The studies included in this meta-analysis were all published within the past 8 years, during which time MRA techniques have changed significantly, Koelemay et al point out.
"Image acquisition time has been reduced from more than 1 hour to a few minutes; susceptibility to flow artifacts and image quality have been improved by electrocardiogram triggering, gadolinium contrast, and subtraction techniques. Moreover, the value of new contrast agents or MR sequences has not yet been tested in comparative studies. These innovations suggest that MRA techniques and their definitive role in clinical practice are still evolving."
The authors also add that little is known about the value of MRA in improved clinical outcomes. They note that the patients who derive most benefit from percutaneous interventions are those with critical limb ischemia, not claudication, and most of the patients in their meta-analysis had claudication.
Although the quality of studies with MRA has improved over the years, Koelemay et al say the studies can be made even better. The researchers call for standardization of both study designs and reporting of results to facilitate the dissemination of MRA technology.
