DOI:10.2214/AJR.06.5023
AJR 2006; 186:1197-1198
© American Roentgen Ray Society
Inflammatory Hyperenhancement Persists in Delayed High-Resolution MRI in Giant Cell Arteritis
T. A. Bley1,
M. Markl1 and
O. Wieben2
1 Department of Diagnostic Radiology and Medical Physics University Hospital
Freiburg, Germany
2 Department of Medical Physics and Radiology University of Wisconsin
Madison, WI
We read with great interest the article by Desai et al.
[1] reporting on
contrast-enhanced MR imaging of delayed hyperenhancement and the pictorial
essay by Gotway et al. [2] on
imaging findings in patients with Takayasu's arteritis and congratulate the
authors on their results. We share the authors' motivation in noninvasive MRI
assessment of inflammatory vessel wall disease as we investigated methods to
detect mural inflammatory changes in giant cell (temporal) arteritis (GCA),
which is a form of vasculitis occurring in large- and medium-sized vessels and
is nontrivial to diagnose. Both entities—giant cell arteritis and
Takayasu's arteritis—share pathogenic pathways with cellular immune
responses involving T cells, antigen-presenting cells, and macrophages
[3]. Specifically, we would
like to point out that high-resolution MRI has proven to be feasible for the
visualization even of small branch vessels such as the superficial temporal
arteries. Here we would like to share our findings over the course of the
previous 26 months from imaging patients suspected of having GCA.
The depiction of mural inflammatory changes of the rather small-sized
superficial cranial arteries requires very high resolution. Therefore, we
acquired multislice T1-weighted spin-echo sequences with a submillimeter
spatial resolution of 196 µm x 260 µm and a slice thickness of 3
mm before and after IV injection of a contrast bolus (0.1 mmol/kg, Magnevist,
Schering) (Figs. 1A and
1B). With this approach, the
superficial cranial arteries could be sharply depicted, allowing for an
evaluation of their lumen and vessel wall dimensions and the grading of a
contrast enhancement score [4].
We found very good agreement with the histologic results and the diagnosis
according to the criteria of the American College of Rheumatology. This
approach offered valuable information on the intensity of mural inflammatory
changes and provided insight into the involvement pattern of the different
cranial arteries [5].
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Fig. 1A —65-year-old man with histologically proven giant cell arteritis.
Spin-echo MR images planned perpendicular to vessel's track of superficial
temporal artery (arrows). Unenhanced image shows subcutaneous tissue
thickening.
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Fig. 1B —65-year-old man with histologically proven giant cell arteritis.
Spin-echo MR images planned perpendicular to vessel's track of superficial
temporal artery (arrows). Image acquisition initiated 1 min after
venous injection of gadolinium-based contrast agent. Pronounced
hyperenhancement of thickened vessel wall and perivascular tissue indicating
acute inflammation is readily revealed.
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In our experience, it is not necessary to restrict vascular delayed
enhancement imaging to a specific time delay. We found that T1-weighted vessel
wall imaging is quite insensitive to the selected delay following contrast
agent administration. MRI signal intensity behavior with respect to the timing
of the spin-echo acquisition is illustrated for a patient with GCA in Figures
1A,
1B,
1C, and
1D. Associated inflammatory
signal changes could be clearly identified in the superficial cranial arteries
without significant changes for different delays following contrast agent
administration. This illustrates the robustness of T1-weighted imaging of the
vessel wall with respect to the delay in the injection of the bolus.
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Fig. 1C —65-year-old man with histologically proven giant cell arteritis.
Spin-echo MR images planned perpendicular to vessel's track of superficial
temporal artery (arrows). Image acquisition initiated 8 min after
injection of contrast agent with same image parameters as in B. Only
slightly decreased hyperenhancement.
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Fig. 1D —65-year-old man with histologically proven giant cell arteritis.
Spin-echo MR images planned perpendicular to vessel's track of superficial
temporal artery (arrows). Image acquisition initiated 15 min after
injection of contrast agent with same image parameters as in B and
C. Mural hyperenhancement is still readily definable.
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GCA usually affects the superficial cranial arteries. However, involvement
of other vascular structures such as the vertebral arteries, the aorta and its
branches, the coronary arteries, the mesenteric arteries, and the lower leg
arteries also can occur. It is therefore advantageous to know the exact
vascular involvement pattern of the individual patient.
Combining high-resolution assessment of the cranial arteries with analysis
of the involvement of the aortic wall as presented by Desai et al.
[1] should be feasible without
the need for additional contrast agent injections or an increase in dosage. In
addition, the contrast agent may even be further utilized by combining such
studies with first-pass MR angiography for assessment of vascular geometries
and potential detection of stenoses associated with inflammatory diseases.
References
- Desai MY, Stone JH, Foo TK, Hellmann DB, Lima JA, Bluemke DA.
Delayed contrast-enhanced MRI of the aortic wall in Takayasu's arteritis:
initial experience. AJR 2005;184
: 1427-1431[Abstract/Free Full Text]
- Gotway MB, Araoz PA, Macedo TA, et al. Imaging findings in
Takayasu's arteritis. AJR 2005;184
: 1945-1950[Abstract/Free Full Text]
- Weyand CM, Goronzy JJ. Medium- and large-vessel vasculitis.
N Engl J Med 2003;349
: 160-169[Free Full Text]
- Bley TA, Wieben O, Uhl M, Thiel J, Schmidt D, Langer M.
High-resolution MRI in giant cell arteritis: imaging of the wall of the
superficial temporal artery. AJR 2005;184
: 283-287[Abstract/Free Full Text]
- Bley TA, Wieben O, Uhl M, et al. Assessment of the cranial
involvement pattern of giant cell arteritis with 3 T magnetic resonance
imaging. Arthritis Rheum 2005;52
: 2470-2477[CrossRef][Medline]
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