Comparison of SPECT/CT, SPECT, and Planar Imaging with Single- and Dual-Phase 99mTc-Sestamibi Parathyroid Scintigraphy

Abstract

Various methodologies for 99m Tc-sestamibi parathyroid scintigraphy are in clinical use. There are few direct comparisons between the different methods and even less evidence supporting the superiority of one over another. Some reports suggest that SPECT is superior to planar imaging. The addition of CT to SPECT may further improve parathyroid adenoma localization. The purpose of our investigation was to compare hybrid SPECT/CT, SPECT, and planar imaging and to determine whether dual-phase imaging is advantageous for the 3 methodologies. Methods: Scintigraphy was performed on 110 patients with primary hyperparathyroidism and no prior neck surgery. Of these, 98 had single adenomas and are the subject of this review. Planar imaging and SPECT/CT were performed at 15 min and 2 h after injection. Six image sets (early and delayed planar imaging, SPECT, and SPECT/CT) and combinations of the 2 image sets were reviewed for adenoma localization at 13 possible sites. Each review was scored for location and certainty of focus by 2 reviewer groups. Surgical location served as the standard. Sensitivity, specificity, area under the curve, positive predictive value, negative predictive value, and k-values were determined for each method. Results: The overall k-coefficient (certainty of adenoma focus) between reading groups was 0.68 (95% confidence interval, 0.66-0.70). The highest values were for dualphase studies that included SPECT/CT. Dual-phase planar imaging, SPECT, and SPECT/CT were statistically significantly superior to single-phase early or delayed imaging in sensitivity, area under the curve, and positive predictive value. Neither single-phase nor dual-phase SPECT was statistically superior to dual-phase planar imaging. Early-phase SPECT/CT in combination with any delayed imaging method was superior to dualphase planar imaging or SPECT for sensitivity, area under the curve, and positive predictive value. Conclusion: Early SPECT/ CT in combination with any delayed imaging method was statistically significantly superior to any single-or dual-phase planar or SPECT study for parathyroid adenoma localization. Localization with dual-phase acquisition was more accurate than with singlephase 99m Tc-sestamibi scintigraphy for planar imaging, SPECT, and SPECT/CT.

Diagnostic accuracy of planar, SPECT, and SPECT/CT parathyroid scintigraphy protocols in patients with hyperparathyroidism

“…This could be because patients who underwent DTDP imaging were patients who initially underwent DT imaging and findings from the initial Tc-99m sestamibi and Tc-99m pertechnetate images were deemed insufficient for diagnosis by the nuclear medicine physician on duty thus prompting further delayed imaging, so patients in the DTDP group represented 'difficult' patients which findings were likely to be inconclusive to begin with. Both add-on SPECT and SPECT/CT improved the diagnostic accuracy over planar imaging alone which concurs with previous studies [5,[16][17][18][19]28]. However, SPECT imaging appeared to have a higher diagnostic accuracy than SPECT/CT which is unexpected and contradicts a previous study which demonstrated the superiority of SPECT/CT over SPECT alone [29].…”

“…The dual phase (DP) protocol compares two or more Tc-99m sestamibi images obtained at Original different time points and diagnosis is based on the observation that Tc-99m sestamibi washes out of the thyroid more rapidly than from hyperfunctioning parathyroid lesions [15]. Tomographic imaging including single photon emission computed tomography (SPECT) and single photon emission computed tomography/computed tomography (SPECT/CT) has been suggested to provide improved diagnostic accuracy over planar imaging [16][17][18][19]. The purpose of this study was to determine the diagnostic accuracy of various nuclear medicine parathyroid imaging techniques for preoperative localization of hyperfunctioning parathyroid glands.…”

Usefulness of SPECT/CT in Parathyroid Lesion Detection in Patients with Thyroid Parenchymal 99mTc-Sestamibi Retention

“…Compared to other conventional imaging modalities such as ultrasonogram (US), computed tomography (CT), and magnetic resonance (MR), 99m Tc-2-methoxy-2-methylpropyl isonitrile ( 99m Tc-sestamibi, MIBI) parathyroid scintigraphy has been shown to have higher sensitivity in detecting parathyroid adenomas [1,2]. In addition, the anatomical information provided by single positron emission computed tomography/computed tomography (SPECT/ CT) has improved the detection and localization of parathyroid lesions compared to planar scans alone [3,4].…”

Improved Delineation of Parathyroid Lesions in Patients with Chronic Renal Failure Using Magnified Pinhole Imaging

“…More recently, the introduction of SPECT/CT has been advocated to more accurately localize parathyroid lesions (17,18). Further experience with SPECT/CT could show more benefits.…”