Thyroid perfusion imaging as a diagnostic tool in Graves' disease--arterial spin labeling magnetic resonance imaging vs. colour-coded Doppler ultrasound.
OBJECTIVE
Though increased thyroid perfusion assessed by colour-coded Doppler ultrasound (CDUS) is characteristic of Graves' disease (GD), sometimes perfusion assessment by CDUS is not possible. In these cases, arterial spin labelling (ASL), a novel magnetic resonance imaging (MRI) technique allowing non-invasive thyroid perfusion quantification, may have additional diagnostic value. We aimed to evaluate the potential of ASL-MRI for assessment of increased blood perfusion in patients with GD compared to CDUS.


METHODS
Thyroid perfusion was measured by CDUS (volume flow rate calculated from pulsed wave Doppler signals and vessel diameter) and ASL-MRI at 1.5 T in 7 patients with GD and 10 healthy controls.


RESULTS
In patients with GD, average perfusion in both thyroid lobes was markedly increased compared to controls. Both techniques applied for volume related perfusion as well as absolute volume flow in thyroid feeding vessels provided similar results (all p=0.0008). Using a cut-off value of 22 ml/min for the volume flow rate assessed by CDUS in the four feeding vessels allowed discrimination between patients with GD and controls in all cases. After adjusting thyroid perfusion for the differences in organ volume, both CDUS and ASL revealed also complete discrimination between health and disease.


CONCLUSIONS
Thyroid perfusion measurement by ASL-MRI reliably discriminate GD from normal thyroid glands. In patients in whom thyroid arteries cannot be depicted by CDUS for technical or anatomical reasons, ASL-MRI may have additional diagnostic value.
Department of Metabolic Diseases, University Hospital of Düsseldorf, Düsseldorf, Germany. karsten.muessig@med.uni-duesseldorf.de
K
K
Müssig
C
C
Schraml
R
R
Rietig
P
P
Martirosian
N F
NF
Schwenzer
C D
CD
Claussen
H-U
HU
Häring
F
F
Schick
B
B
Balletshofer
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D003937:Diagnosis, Differential; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005260:Female; D006111:Graves Disease / Q000175:diagnosis*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012680:Sensitivity and Specificity; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000098:blood supply*; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods; D055815:Young Adult
D018828:Immunoglobulins, Thyroid-Stimulating; C094372:thyrotropin-binding inhibitory immunoglobulin