title: Intravenous versus intra-articular delayed gadolinium-enhanced magnetic resonance imaging in the hip joint: a comparative analysis.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether T1-mapping of hip joint with intra-articular delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (ia-dGEMRIC) is comparable to the already established intravenous (iv)-technique for assessing different grades of cartilage degeneration.
  
  
  METHODS
  The study cohort consisted of 53 patients with symptomatic femoroacetabular impingement (FAI) that were randomly recruited for either iv-dGEMRIC or ia-dGEMRIC studies. RI was performed in supine position at a 1.5 Tesla (T) system (Magnetom Avanto, Siemens, Erlangen, Germany) using a body matrix-phased array coil. Twenty-six patients (18 males, 8 females; mean age +/- standard deviation [SD]: 32.1 +/- 8.8 years, range: 17-49 years) underwent iv-dGEMRIC whereas 27 patients (17 males, 10 females; mean age 34.0 +/- 10.8 years, range: 13.0-57 years) underwent ia-dGEMRIC mapping. On average patients suffered from FAI for 23.9 +/- 20.9 months in the iv-dGEMRIC group (range: 5-108 months) whereas FAI was symptomatic for 20.9 +/- 25.2 months in the ia-dGEMRIC group (range: 3-120 months). Patient demographics and symptomatology in both groups were not statistically different.
  
  
  RESULTS
  Mapping with both techniques (iv and ia) demonstrated appropriately similar differences between various grades of cartilage degeneration. Overall, there was no significant difference between iv-dGEMRIC and ia-dGEMRIC T1 mean values in all grades of cartilage findings (P: 0.394, 0.400, and 0.173). Of note, the T1 values after iv-dGEMRIC were higher (544.3 +/- 104.2 milliseconds) in regions with cartilage damage extent <0.75 cm than in regions where no damage was noted (535.7 +/- 112.4 milliseconds). After ia-dGEMRIC the T1 values were similar (521.2 +/- 125.1 milliseconds vs. 521.1 +/- 94.3 milliseconds).
  
  
  CONCLUSIONS
  Intravenous contrast remains the standard method of contrast administration in the current scenario when dGEMRIC imaging is performed. Our results demonstrate that the information and mapping values obtained by the ia-technique are similar to those of the iv-technique. The intravenous route can have its own problems in certain patients with impaired renal function tests or when parenteral access is an issue in many patients. Intra-articular technique could be a good alternative in such cases whereas maintaining the quality of imaging and obtained information. Thus, in well-selected cases ia-dGEMRIC mapping may be a potential alternative to iv-dGEMRIC for hip joint cartilage analysis.
  
  
  METHODS
  Prospective case series, Diagnostic study comparing different modalities of assessing status of hip joint cartilage: Level II evidence.
authors.affiliation: Department of Orthopedic Surgery, University of Bern, Inselspital, Bern, Switzerland.
authors.forename: Bernd
authors.initials: B
authors.lastname: Bittersohl
authors.forename: Harish S
authors.initials: HS
authors.lastname: Hosalkar
authors.forename: Stefan
authors.initials: S
authors.lastname: Werlen
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
authors.forename: Klaus A
authors.initials: KA
authors.lastname: Siebenrock
authors.forename: Tallal C
authors.initials: TC
authors.lastname: Mamisch
mesh_terms: D000293:Adolescent; D000328:Adult; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology; D015331:Cohort Studies; D003287:Contrast Media; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D005682:Gadolinium; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007262:Infusions, Intravenous; D007270:Injections, Intra-Articular; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium