Correlation between serum calcium levels and dual-phase 99mTc-sestamibi parathyroid scintigraphy in primary hyperparathyroidism

The Relationship between Planar and SPECT/CT Parameters and Functional Markers in Primary Hyperparathyroidism

This study aimed to investigate the relationship between quantitative and volumetric parameters of technetium-99-methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) imaging and hormonal and biochemical markers in primary hyperparathyroidism (PHPT) patients with single adenoma. In this retrospective study, 70 patients with a single adenoma who underwent 99mTc-MIBI imaging for the diagnosis of PHPT were examined. Early and delayed MIBI lesion/background ratios (eLBR and dLBR), early and delayed lesion/thyroid ratio (eLTR and dLTR), and retention index (RI) were calculated as planar dual-phase scintigraphy parameters. Adenoma volume (Svol) and parathormone (PTH)/Svol ratio were measured as SPECT/CT-derived parameters. Calcium levels exhibited a positive correlation with eLBR (r = 0.33, p < 0.001), dLBR (r = 0.29, p = 0.01), dLTR (r = 0.31, p < 0.001), and PTH/Svol (r = 0.38, p < 0.001). PTH did not correlate with planar parameters and Svol. Among the imaging parameters, only the PTH/Svol ratio showed a negative correlation with phosphorus levels (r = -0.29, p = 0.02). For predicting disease severity, the PTH/Svol ratio exhibited similar diagnostic performance to PTH and phosphorus levels but outperformed the eLBR and dLBR. Both planar and SPECT-derived parameters can provide valuable insights into the functional status of the parathyroid adenoma and the associated disease severity. PTH/Svol ratio, combining imaging and laboratory findings to provide a more comprehensive approach to patient care, could be an exciting new indicator.

Clinicopathological variables that correlate with sestamibi positivity in uniglandular parathyroid disease: a retrospective analysis of 378 parathyroid adenomas

PURPOSE

Technetium-99 m sestamibi parathyroid scintigraphy (MIBI scan) has been used to localize abnormal glands in patients with primary hyperparathyroidism to guide parathyroidectomy. This series aimed to identify the biochemical and histopathological correlates of MIBI scan findings in patients with parathyroid adenoma.

METHODS

A total of 378 patients with histologically and biochemically proven parathyroid adenoma were included. The results of MIBI scan, histopathological (gland volume and weight, oxyphil cell ratio), biochemical (blood and 24 h urine calcium, creatinine, glomerular filtration rate, parathormone, alkaline phosphate, and vitamin D3) variables were recorded. A positive uptake on the MIBI scan referred to a localized adenoma. Among histological variables, a cutoff of 30% was applied to define parathyroid adenomas with low (≤ 30%) and high (> 30%) oxyphil cell content. Statistical analyses were performed to assess the relationship among variables.

RESULTS

MIBI scan localized the adenoma in 306 patients. Parathyroid gland volume and weight, and oxyphil ratio were significantly higher in the MIBI scan-positive group. Among the biochemical variables, only PTH was found to be significantly increased in the MIBI scan-positive group. Binary logistic regression models identified statistically significant cutoffs for the gland volume (1700 mm3), gland weight (1.3 g) and PTH levels (170 pg/mL) that can be used to predict the MIBI scan positivity.

CONCLUSION

In addition to PTH levels, this series underscored the impact of cellular composition along with the parathyroid gland volume and weight, both of which correlate with sestamibi positivity in patients with benign uniglandular parathyroid disease.

The value of parathyroid scintigraphy on lesion detection in patients with normocalcemic primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases. Most of the patients with PHPT are asymptomatic, and only 20% of them become symptomatic with increasing levels of calcium. It has been reported that normocalcemic primary hyperparathyroidism (NPHPT) may be the incipient period of PHPT where calcium (Ca) levels are in normal range, and it may advance to overt PHPT. Early diagnosis of PHPT is important in order to prevent its complications. In this retrospective study, we aimed to evaluate the role of 99mTc-MIBI parathyroid scintigraphy on lesion detection in patients with NPHPT.

MATERIAL AND METHODS

The parathyroid scintigraphy database was reviewed retrospectively in patients with PHPT. 117 patients who underwent 99mTc-MIBI scintigraphy were recruited to the study. Serum calcium level above 10.5mg/dl was considered as hypercalcemia.

RESULTS

A total of 117 patients' (female/male:98/19) mean serum PTH levels (mean±SD) were 149±97 pg/ml in normocalcemic group (Ca:9.6±0.6mg/dL, n:38) and 189±135 pg/ml in hypercalcemic group (Ca:11.4±0.6mg/dL, n:79) (p:0.072). The sex and ages were not different between the scintigraphy positive and negative groups, but the lesion detection rates with parathyroid scintigraphy were 42% in normocalcemic group and 81% in hypercalcemic group (p<0.0001).

CONCLUSIONS

Several factors including serum Ca, the imaging protocol, existence of multiglandular disease, the size and MIBI biokinetics of the adenoma may influence lesion detectability in parathyroid scintigraphy. Although high serum Ca level is an important parameter in predicting its success, parathyroid scintigraphy remains a valuable diagnostic method even in patients with NPHPT.

Radioactive Parathyroid Adenomas on Sestamibi Scans: Low Parathyroid Hormone Secretory Potential and Large Volume

BACKGROUND

We investigated the clinical characteristics of parathyroid adenomas according to radioactivity on 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) in primary hyperparathyroidism (PHPT) patients.

METHODS

The study included 217 patients diagnosed with PHPT from 2000 to 2019 at Seoul National University Hospital who underwent 99mTc-MIBI SPECT/CT scans. On SPECT/CT, the radioactivity of parathyroid adenomas was measured as the ratio of the mean radioactivity count of the parathyroid adenoma to that of the contralateral thyroid.

RESULTS

Tumors were localized by MIBI scans in 190 patients (MIBI [+] group) and by ultrasound or parathyroid four-dimensional CT in 27 patients (MIBI [-] group). The mean age was 55 years, and mean body mass index was 23.4 kg/m2. Patients in the MIBI (+) group had higher parathyroid hormone (iPTH) and lower 25-hydroxy vitamin D levels than those in the MIBI (-) group (168.0 pg/mL [interquartile range, IQR, 111.0 to 250.7] vs. 134.7 pg/mL [IQR, 98.2 to 191.2], P=0.049; 15.4 ng/mL [IQR, 11.1 to 20.8] vs. 21.2 ng/mL [IQR, 13.9 to 24.8], P=0.012, respectively). Patients in the MIBI (+) group had larger tumor volumes, but lower iPTH/volume ratios than those in the MIBI (-) group (1,216.66 [IQR, 513.40 to 2,663.02], 499.82 mm3 [IQR, 167.77 to 1,229.80], P=0.002; 0.18 [IQR, 0.08 to 0.46], 0.40 pg/mL/mm3 [IQR, 0.16 to 1.29], P=0.016, respectively). Adenoma radioactivity was positively correlated with calcium, iPTH, and volume (r=0.180, P=0.020; r=0.208, P=0.006; r=0.288, P<0.001, respectively), but not with iPTH/volume.

CONCLUSION

Parathyroid adenomas with positive MIBI scans had larger volumes and higher iPTH than adenomas with negative scans, but lower iPTH per unit volume.

VEGFR-2 is downregulated in sestamibi-negative parathyroid adenomas

BACKGROUND

The purpose of this study was to determine the expression profile of several biomarkers in sestamibi-positive (n = 23) and sestamibi-negative (n = 6) parathyroid adenomas.

METHODS

A tissue microarray of parathyroid adenomas from 29 patients was constructed and slides were stained for several proteins involved in angiogenesis, inflammation, cell adhesion, cell cycle, apoptosis, and with markers of the sonic hedgehog, mTOR, Forkhead box O and WNT signal transduction pathways. Protein expression was determined using an image-analysis software (Spectrum Plus©, 38 Aperio).

RESULTS

Protein expression analysis revealed that the vascular endothelial growth factor receptor 2 (VEGFR2) score was significantly higher in the sestamibi-positive cohort compared to sestamibi-negative adenomas (P = .038). Other proteins were not differentially expressed between sestamibi-positive and sestamibi-negative adenomas.

CONCLUSION

It is hypothesized that VEGFR-2 overexpression in parathyroid adenomas increases vascular permeability resulting in a higher uptake of sestamibi.

Biochemical and pathologic factors affecting technetium-99m-methoxyisobutylisonitrile imaging results in patients with primary hyperparathyroidism

OBJECTIVE

Technetium 99 m methoxyisobutylisonitrile (Tc-99m MIBI) scintigraphy represents the most commonly utilized imaging modality for the detection of the diseased gland in patients with primary hyperparathyroidism (PHPT). In this study, we aimed to identify potential biological factors with an impact on MIBI sensitivity.

METHODS

A total of 147 patients with surgically confirmed parathyroid adenomas were assessed retrospectively. Data including medical history, biochemical and hormonal measurements, cervical US, Tc-99m MIBI scans as well as pathology reports were retrieved and recorded.

RESULTS

Of the 147 patients, there were a total of 77, 39, and 31 cases with a positive, negative, and suspicious parathyroid adenoma on Tc-99m MIBI scan, respectively. Serum calcium (Ca), parathyroid hormone (PTH) and 25 (OH) D levels were comparable among MIBI positive and negative patients [Ca: 11.5 ± 0.9 vs 11.3 ± 0.9 mg/dL (P = 0.42); PTH: 216 (146-347) vs 194 (140-317) pg/mL (P = 0.45); 25(OH)D: 8.4 (5.7-18.2) vs 10.0 (4.7-23.3) ng/mL (P = 0.64), respectively]. P-glycoprotein (P-gp) staining was negative in both groups. Also, pathological examination of tissue preparations revealed no difference in terms of the volume of the adenomas, incidence of cystic adenomas, cell-type dominance (oxyphilic cell), percent fat, and Ki-67 ratio in MIBI positive and negative groups. The rate of hyalinization was 13% in MIBI positive and 28% in MIBI negative subjects, the difference being statistically significant (P = 0.04).

CONCLUSION

Presence of hyalinization in parathyroid adenomas was found to be negatively correlated with MIBI scan results.

Combined application of ultrasound and SPECT/CT has incremental value in detecting parathyroid tissue in SHPT patients

PURPOSE

The goal of this study is to investigate whether combined application of ultrasound and 99mTc-sestamibi SPECT/CT had the incremental value in accurately detecting parathyroid tissue in patients with SHPT over either method alone.

PATIENTS AND METHODS

Sixty patients with SHPT on hemodialysis were evaluated preoperatively with parathyroid 99mTc-sestamibi SPECT/CT scintigraphy and ultrasound prior to parathyroidectomy. The sensitivity, specificity and accuracy of 99mTc-sestamibi SPECT/CT scintigraphy, ultrasound and combined application were determined respectively.

RESULTS

The sensitivity, specificity and accuracy of ultrasound were 81% (155/192), 47% (17/36) and 82% (172/228), respectively. The sensitivity, specificity and accuracy of 99mTc-sestamibi SPECT/CT were 85% (163/192), 58% (21/36) and 89% (184/228) respectively. The accuracy of 99mTc-sestamibi SPECT/CT in the diagnosis of parathyroid tissue in patients with SHPT is significantly higher than that of ultrasound. The sensitivity, specificity and accuracy of combined application of ultrasound and 99mTc-sestamibi SPECT/CT were 93% (178/192), 61% (22/36) and 97% (200/228). The sensitivity, specificity and accuracy of combined application of ultrasound and 99mTc-sestamibi SPECT/CT were higher than those of either ultrasound or 99mTc-sestamibi SPECT/CT.

CONCLUSIONS

The combined application of ultrasound and 99mTc-sestamibi SPECT/CT had incremental value in accurately detecting parathyroid tissue in patients with SHPT over either method alone.

Functional evaluation of parathyroid adenoma using 99mTc-MIBI parathyroid SPECT/CT: correlation with functional markers and disease severity

OBJECTIVES

In parathyroid adenoma, uptake of technetium-99m-methoxyisobutylisonitrile ((99m)Tc-MIBI) has been suggested to have a correlation with functional markers. The purpose of this study was to evaluate the feasibility of (99m)Tc-MIBI parathyroid single photon emission computed tomography/computed tomography (SPECT/CT) in evaluating the function and disease severity of parathyroid adenoma.

PATIENTS AND METHODS

Twenty-three patients with surgically confirmed parathyroid adenoma were retrospectively enrolled. A parathyroid planar scan and SPECT/CT were performed before parathyroidectomy. Functional and clinical makers reflecting the disease severity of parathyroid adenoma were also evaluated, including serum intact parathyroid hormone, calcium, bone mineral density, and creatinine clearance. The pathologic volume (V(P)) of the adenoma was measured after parathyroidectomy. On parathyroid SPECT/CT, metabolic volume (V(M)) was measured using an isocontour method. Maximum uptakes of parathyroid adenoma and mean uptakes of contralateral thyroid tissue were measured to calculate the parathyroid adenoma-to-background ratio on parathyroid SPECT/CT (PBR(SCT)) and planar scan (PBR(PL)).

RESULTS

V(M) significantly correlated with V(P) (r=0.669, P=0.0005). Serum intact parathyroid hormone level significantly correlated with PBR(PL), PBR(SCT), V(M), and V(P) (P=0.0004, 0.005, 0.003, and 0.025, respectively). However, serum calcium level correlated only with V(M) (P=0.012). Regarding the surgical indication criteria, PBR(SCT) and PBR(PL) were significantly higher in the young-aged group (P=0.0004 and 0.024, respectively) and V(M) was significantly higher in the high calcium level group (P=0.049), whereas V(P) was not different between groups on the basis of any criteria.

CONCLUSION

Quantitative indices of parathyroid SPECT/CT closely correlate with laboratory functional markers and disease severity of parathyroid adenoma. Thus, parathyroid SPECT/CT could be used for evaluation of the underlying functional state and disease severity of parathyroid adenoma, particularly for decision pertaining to surgical treatment.

The biochemical severity of primary hyperparathyroidism correlates with the localization accuracy of sestamibi and surgeon-performed ultrasound

BACKGROUND

Minimally invasive parathyroidectomy for primary hyperparathyroidism is dependent on preoperative localization, commonly with ultrasound and sestamibi imaging. This study sought to determine if preoperative serum calcium and parathyroid hormone (PTH) levels correlate with localization sensitivity and positive predictive value (PPV).

STUDY DESIGN

This is a retrospective analysis of a prospective database of 1,910 patients with primary hyperparathyroidism from 2002 to 2013, who had surgeon-performed ultrasound and/or sestamibi for preoperative localization. The sensitivity and PPV of ultrasound and sestamibi were analyzed by degree of preoperative serum calcium and parathyroid hormone level perturbation.

RESULTS

In 1,910 parathyroidectomy patients, ultrasound was localizing in 1,411 of 1,644 (86%) and sestamibi in 802 of 1,165 (69%) (p < 0.01). The PPV of ultrasound was 1,135 of 1,411 (80%) and sestamibi was 705 of 802 (88%) (p < 0.01). Using logistic regression analysis, there was statistically significant positive correlation between localization and preoperative serum calcium for both sestamibi (odds ratio [OR] 1.21 [95% CI 1.00 to 1.47; p < 0.05]) and ultrasound (OR 1.29 [95% CI 1.03 to 1.60; p < 0.05]). There was a weak, but statistically significant positive correlation of PTH with sestamibi localization (OR 1.00 [95% CI 1.00 to 1.01; p < 0.05]). There was no statistically significant correlation between the PPV and serum calcium or PTH for either study. When patients were divided into quartiles of preoperative serum calcium and PTH levels, localization rates and PPV of both ultrasound and sestamibi increased with higher calcium and PTH levels. Surgeon-performed ultrasound had higher localization rates than sestamibi, with lower calcium and PTH values. Sestamibi demonstrated higher PPV values across all quartiles.

CONCLUSIONS

Surgeon-performed ultrasound and sestamibi have higher localization rates and PPV, with increasing preoperative serum calcium and PTH levels. Surgeon-performed ultrasound may be a better initial test for patients with lower calcium (<10.5 mg/dL) and PTH (<90 pg/mL) values due to significantly higher localization rates; however, a localizing sestamibi has higher PPV.

The relationship between technetium-99m-methoxyisobutyl isonitrile parathyroid scintigraphy and hormonal and biochemical markers in suspicion of primary hyperparathyroidism

OBJECTIVE

Technetium-99m-methoxyisobutyl isonitrile (Tc-99m MIBI) has been widely used to evaluate hyperfunctioning autonomous parathyroid glands in patients with elevated intact parathyroid hormone (iPTH) and/or calcium (Ca) level. The aim of this study was to evaluate the relationship between Tc-99m MIBI parathyroid scintigraphy and hormonal and biochemical markers in suspicion of primary hyperparathyroidism (PHPT).

MATERIAL AND METHODS

Dual-phase Tc-99m MIBI parathyroid scintigraphy and total serum iPTH, Ca, phosphorus (P) and albumin measurements were performed in 60 patients (52 females, 8 males; mean age, 59.38±12.51 years; range, 34 to 86 years) with suspicion of PHPT.

RESULTS

The iPTH median level was 160.3 pg/mL (47.8 to 782.6). Thirty-five of the patients had surgical resection of hyperfunctioning parathyroid glands. Of the 35 patients, parathyroid gland pathology was detected in 30 patients using scintigraphic examination. Tc-99m MIBI parathyroid scintigraphy was negative in 30 patients. The iPTH, Ca and P levels were significantly different between in the Tc-99m MIBI positive group and the negative group, respectively: For iPTH, 202.1 (47.8-782.6) pg/mL versus 111.6 (80.1-373) pg/mL; p<0.001. For Ca, 11.7±1.15 mg/dL versus 10.3±1.05 mg/dL; p<0.001 and for P levels, 2.46±0.62 mg/dL versus 3.40±0.70 mg/dL; p<0.001). There was no significant difference in serum albumin levels between the MIBI positive and MIBI negative groups (4.25±0.27 g/dL versus 4.25±0.41 g/dL; p>0.05). Tc-99m MIBI parathyroid scintigraphy showed good correlation with iPTH level and histopathological diagnosis. Sensitivity and specificity was found 83.3% and 76.7%, respectively at the level of iPTH>147.7pg/mL.

CONCLUSION

Tc-99m MIBI parathyroid scintigraphy is most likely to produce identification and localization of a parathyroid adenoma when both iPTH and Ca are elevated as well as decreased P levels.

CONFLICT OF INTEREST

None declared.