Magnetic resonance imaging (MRI) and technetium-99m-methoxyisonitrile (MIBI) scintigraphy to evaluate the abnormal parathyroid gland and PEIT efficacy for secondary hyperparathyroidism.
OBJECTIVE
Percutaneous ethanol injection therapy (PEIT) of the abnormal parathyroid gland is an effective treatment in patients with chronic renal failure with dialysis that tends to be unresponsive to medication. To evaluate the efficacy of PEIT, we investigated the correlation between serum intact PTH (iPTH), and the findings of MR imaging and 99mTc-MIBI scintigraphy.


METHODS
PEIT was performed 32 times in 24 patients with secondary hyperparathyroidism. Both MR imaging and MIBI scintigraphy were performed before and after PEIT. The detectability of parathyroid lesions was evaluated by MRI and MIBI scintigraphy with reference to ultrasound (B-mode) findings (as a standard) and the comparison of each treatment was done between imaging changes and serum iPTH levels.


RESULTS
In the small parathyroid glands (< 0.5 ml with US), MR images detected abnormal glands in 74.0% (20/27), and MIBI accumulation was observed in 40.7% of the cases. Whereas, MR images and MIBI showed similar detectability (95.0% vs. 90.0%) to large parathyroid glands (> or = 0.5 ml with US). After PEIT, glands in which ethanol was successfully injected showed decreased signal intensity on T2-weighted images and decreased accumulation of MIBI. MR imaging and MIBI scintigraphy showed almost equivalent high sensitivity in evaluating therapeutic changes (73.3% vs. 76.4%) according to our evaluation category of more than 30% reduction of iPTH as effective. However, the specificity of MR imaging was much higher (100%) than that of MIBI scintigraphy in evaluating therapeutic effects.


CONCLUSIONS
In conclusion, MRI provided better detectability of abnormal parathyroid glands than 99mTc-MIBI scintigraphy. The reduction of high signal intensity area after PEIT on T2-weighted MR images is considered an useful therapeutic evaluation guideline than the reduction of MIBI accumulation on scintigraphy.
Wada
A
A
Department of Radiology, Shimane Medical University, Izumo, Japan.
Sugihara
M
M
Sugimura
K
K
Kuroda
H
H
D000328:Adult; D000368:Aged; D000431:Ethanol / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D007267:Injections; D007676:Kidney Failure, Chronic / Q000150:complications; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000473:pathology*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D016896:Treatment Outcome
D019275:Radiopharmaceuticals; D000431:Ethanol; D017256:Technetium Tc 99m Sestamibi