title: Clinical utility of time-resolved imaging of contrast kinetics (TRICKS) magnetic resonance angiography for infrageniculate arterial occlusive disease.
abstract: OBJECTIVE
  The diagnostic accuracy of magnetic resonance angiography (MRA) in the infrapopliteal arterial segment is not well defined. This study evaluated the clinical utility and diagnostic accuracy of time-resolved imaging of contrast kinetics (TRICKS) MRA compared with digital subtraction contrast angiography (DSA) in planning for percutaneous interventions of popliteal and infrapopliteal arterial occlusive disease.
  
  
  METHODS
  Patients who underwent percutaneous lower extremity interventions for popliteal or tibial occlusive disease were identified for this study. Preprocedural TRICKS MRA was performed with 1.5 Tesla (GE Healthcare, Waukesha, Wis) magnetic resonance imaging scanners with a flexible peripheral vascular coil, using the TRICKS technique with gadodiamide injection. DSA was performed using standard techniques in angiography suite with a 15-inch image intensifier. DSA was considered the gold standard. The MRA and DSA were then evaluated in a blinded fashion by a radiologist and a vascular surgeon. The popliteal artery and tibioperoneal trunk were evaluated separately, and the tibial arteries were divided into proximal, mid, and distal segments. Each segment was interpreted as normal (0% to 49% stenosis), stenotic (50% to 99% stenosis), or occluded (100%). Lesion morphology was classified according to the TransAtlantic Inter-Society Consensus (TASC). We calculated concordance between the imaging studies and the sensitivity and specificity of MRA. The clinical utility of MRA was also assessed in terms of identifying arterial access site as well as predicting technical success of the percutaneous treatment.
  
  
  RESULTS
  Comparisons were done on 150 arterial segments in 30 limbs of 27 patients. When evaluated by TASC classification, TRICKS MRA correlated with DSA in 83% of the popliteal and in 88% of the infrapopliteal segments. MRA correctly identified significant disease of the popliteal artery with a sensitivity of 94% and a specificity of 92%, and of the tibial arteries with a sensitivity of 100% and specificity of 84%. When used to evaluate for stenosis vs occlusion, MRA interpretation agreed with DSA 90% of the time. Disagreement occurred in 15 arterial segments, most commonly in distal tibioperoneal arteries. MRA misdiagnosed occlusion for stenosis in 11 of 15 segments, and stenosis for occlusion in four of 15 segments. Arterial access was accurately planned based on preprocedural MRA findings in 29 of 30 patients. MRA predicted technical success 83% of the time. Five technical failures were due to inability to cross arterial occlusions, all accurately identified by MRA.
  
  
  CONCLUSIONS
  TRICKS MRA is an accurate method of evaluating patients for popliteal and infrapopliteal arterial occlusive disease and can be used for planning percutaneous interventions.
authors.affiliation: Department of Surgery, University of Wisconsin, Madison, WI, USA. mell@surgery.wisc.edu
authors.forename: Matthew
authors.initials: M
authors.lastname: Mell
authors.forename: Girma
authors.initials: G
authors.lastname: Tefera
authors.forename: Frank
authors.initials: F
authors.lastname: Thornton
authors.forename: David
authors.initials: D
authors.lastname: Siepman
authors.forename: William
authors.initials: W
authors.lastname: Turnipseed
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D000800:Angioplasty, Balloon; D001157:Arterial Occlusive Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy; D003251:Constriction, Pathologic / Q000175:diagnosis; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007700:Kinetics; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011150:Popliteal Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D011237:Predictive Value of Tests; D012042:Registries; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016909:Tibial Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D016896:Treatment Outcome; D014922:Wisconsin
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA