Gordon Leonie, Burkhalter William, Mah Eugene
Department of Radiology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
J Nucl Med Technol. 2002 Dec;30(4):179-84.
Dual-phase (99m)Tc-sestamibi (methoxyisobutylisonitrile [MIBI]) imaging is the technique of choice for hyperparathyroidism (HPT), especially for localizing parathyroid adenomas. Prior studies have shown its utility for detecting hyperplasia is equivocal, but we believe this is not true. We attempted to quantitate the region-of-interest counts per pixel between immediate images and delayed images (I/D ratio) and use this ratio to distinguish normal parathyroid versus hyperplasia versus adenoma.
Anterior pinhole and upper thorax images with a low-energy, high-resolution collimator at 20 min and 2 h after (99m)Tc-MIBI injection were obtained on 54 subjects. The results were analyzed retrospectively as hyperplasia, adenoma, or normal parathyroid by the persistence of activity in 2 or more foci, a solitary focus, or no activity on the delayed images. These interpretations were compared with pathology when available. I/D ratios were computed for all scans, and mean ratios were calculated for each type of pathology (normal parathyroid, hyperplasia, and adenoma). The resulting ratios were analyzed with a t test to determine significant differences between the ratios.
Sensitivity and specificity were 96% and 88%, respectively, for parathyroid hyperplasia. Mean I/D ratios were 2.26 +/- 0.68, 2.80 +/- 0.95, and 3.10 +/- 0.77 for subjects with hyperplasia, adenoma, and normal parathyroid, respectively (hyperplasia vs. normal, P = 0.020; adenoma vs. normal, P = 0.381; hyperplasia vs. adenoma, P = 0.033).
Dual-phase (99m)Tc-MIBI imaging is more sensitive and specific for parathyroid hyperplasia than reported previously, supporting its use to localize hyperplastic glands preoperatively and to help guide resection. A thyroid ratio between immediate and delayed images will aid in distinguishing hyperplasia from normal parathyroid in uncertain cases.
双期（99m）锝-甲氧基异丁基异腈（MIBI）显像术是甲状旁腺功能亢进症（HPT）的首选检查技术，尤其适用于甲状旁腺腺瘤的定位。既往研究表明，其检测甲状旁腺增生的效用存在争议，但我们认为并非如此。我们试图对即刻影像与延迟影像之间的每像素感兴趣区计数（I/D比值）进行定量，并利用该比值区分正常甲状旁腺、增生性甲状旁腺与甲状旁腺腺瘤。
对54例受试者在注射（99m）Tc-MIBI后20分钟和2小时，使用低能高分辨率准直器获取前位针孔影像和上胸部影像。根据延迟影像上2个或更多病灶、单个病灶或无活性的放射性持续情况，将结果回顾性分析为增生、腺瘤或正常甲状旁腺。如有病理结果，将这些解读与之进行比较。计算所有扫描的I/D比值，并计算每种病理类型（正常甲状旁腺、增生和腺瘤）的平均比值。用t检验分析所得比值，以确定各比值之间的显著差异。
甲状旁腺增生的敏感性和特异性分别为96%和88%。增生、腺瘤和正常甲状旁腺受试者的平均I/D比值分别为2.26±0.68、2.80±0.95和3.10±0.77（增生与正常相比，P = 0.020；腺瘤与正常相比，P = 0.381；增生与腺瘤相比，P = 0.033）。
双期（99m）Tc-MIBI显像术对甲状旁腺增生的敏感性和特异性高于既往报道，支持其在术前定位增生性腺体及指导切除术中的应用。在不确定的病例中，即刻影像与延迟影像之间的甲状腺比值有助于区分增生性甲状旁腺与正常甲状旁腺。
