In Vivo Intravascular MR Imaging: Transvenous Technique for Arterial Wall Imaging

https://doi.org/10.1097/01.RVI.0000092904.31640.BEGet rights and content

PURPOSE

To determine, in vivo, the potential for transvenous magnetic resonance (MR) imaging of the arterial wall and to assess appropriate MR pulse sequences for this method.

MATERIALS AND METHODS

MR imaging was performed on 19 vessels (right renal artery, N = 9; left renal artery N = 2; external iliac artery, N = 4; abdominal aorta, N = 4) in nine swine. The animals were either low-density lipoprotein receptor knockout (N = 5) or Yucatan mini-pigs fed an atherogenic diet for 6 to 11 weeks (N = 4). The intravascular MR coil/guide wire (IVMRG) (Surgi-Vision, Gaithersburg, MD) was introduced via the external iliac vein into the inferior vena cava (IVC). The following electrocardiograph-gated MR pulse sequences were obtained: T1-weighted precontrast with and without fat saturation and T1-weighted postcontrast with fat saturation. Two observers scored wall signal and conspicuity and classified the vessel as normal, abnormal, or stented. Images were compared with histopathologic findings.

RESULTS

The T1-weighted precontrast without fat saturation, T1-weighted precontrast with fat saturation, and T1-weighted postcontrast images correlated with histopathologic findings in 12 of 15 vessels, eight of 10 vessels, and 14 of 16 vessels, respectively. Abnormal histopathologic findings included: arterial wall thickening (N = 3), arterial dissection (N = 2), focal fibrous plaque (N = 2), adherent thrombus (N = 1). The T1-weighted postcontrast images were not compromised by artifacts and had the highest score for vessel wall signal and conspicuity. T1-weighted precontrast images were compromised by chemical shift artifact and poor blood suppression. Negligible artifacts were created by the platinum stent.

CONCLUSION

The T1-weighted fat saturated postcontrast pulse sequence was superior to other sequences for transvenous MR imaging of the arterial wall.

Section snippets

IVMRG

The IVMRG (Surgi-Vision, Gaithersburg, MD) used in this study is a “receive only” coil and has been previously described (9). Briefly, the device is a 75-cm-long, 0.030-inch-diameter, loopless antenna consisting of a soft conducting wire that has an inner conductor from a 50-ohm, 0.6-mm, coaxial cable with a polyester jacket. The proximal end of the coaxial cable was connected through a matching tuningdecoupling circuit to the MR scanner. The IVMRG can function as a conventional angiography

RESULTS

Forty-one images (T1-weighted precontrast without fat saturation, N = 15); T1-weighted precontrast with fat saturation, N = 10; T1-weighted postcontrast with fat saturation, N = 16) of 19 arteries were reviewed. The Table lists the imaging and histopathologic results. Vessels ranged in size from 4 to 10 mm (average size, 6.6 ± 2.01 mm). The average distance from the center of the artery to the center of the vein was 11.6 ± 6.0 mm.

DISCUSSION

Recently, investigators have used electron-beam CT, multi-detector CT, transcutaneous ultrasound, intravascular ultrasound, and MR imaging to evaluate the arterial wall. Electron-beam CT and multi-detector CT, which have been used for calcium scoring of the coronary arteries, primarily identifies calcified plaques, (AHA type Vb) (1) but has a lower sensitivity in identifying earlier, less advanced lesions (13). Transcutaneous ultrasound is able to not only quantify the plaque burden (14, 15),

References (25)

  • ZimmermannGG et al.

    Intravascular MR imaging of atherosclerotic plaque: ex vivo analysis of human femoral arteries with histologic correlation

    Radiology

    (1997)
  • OcaliO et al.

    Intravascular magnetic resonance imaging using a loopless catheter antenna

    Magn Reson Med

    (1997)
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    This study was supported by a research grant from Surgi-Vision (Gaithersburg, MD). None of the authors have identified a potential conflict of interest.

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