Predictive Value of Parathyroid Scintigraphy in the Preoperative Evaluation of Patients with Primary Hyperparathyroidism

C-11 methionine positron emission tomography scans improve the preoperative localization of pathologic parathyroid glands in primary hyperparathyroidism

BACKGROUND AND AIMS

Preoperative localization of pathologic parathyroid glands is essential in the preparation of a parathyroidectomy. We evaluated the use of a C-11 methionine positron emission tomography/computed tomography scan in a 7-year period in selected patients with primary hyperparathyroidism. The indications to perform a C-11 methionine positron emission tomography/computed tomography were either persistent primary hyperparathyroidism after parathyroidectomy or inconclusive preoperative localization on ultrasound and sestaMIBI.

MATERIALS AND METHODS

A group of 36 patients was referred for a C-11 methionine positron emission tomography/computed tomography. Biochemical data, pathology, and results of sestaMIBI were collected retrospectively. The primary hyperparathyroidism patients were divided into two groups. In group 1 (N = 17), the C-11 methionine positron emission tomography/computed tomography was performed before parathyroidectomy. In group 2 (N = 19), the C-11 methionine positron emission tomography/computed tomography was performed after unsuccessful parathyroidectomy and before a reoperation.

RESULTS

Overall, in 30 of the 36 patients (83%), C-11 methionine positron emission tomography/computed tomography identified a true-positive pathologic parathyroid gland confirmed by an experienced pathologist, consistent with a positive predictive value of 91%. In group 1, 94% of the patients (N = 16) had pathologic parathyroid tissue identified by C-11 methionine positron emission tomography/computed tomography. This resulted in a clinical benefit in 13 patients (76%). In group 2, the benefit was slightly lower, as 74% of the patients (N = 14) had a true-positive C-11 methionine positron emission tomography/computed tomography scan resulting in a clinical benefit in nine patients (47%).

CONCLUSION

In two selected groups of patients planned for an initial operation or reoperation of primary hyperparathyroidism and inconclusive conventional imaging, we found C-11 methionine positron emission tomography/computed tomography to give parathyroid surgeons a clinical benefit in the majority of cases, electing the patients for unilateral surgery.

Advantages of hybrid SPECT-CT imaging in preoperative localization of parathyroid glands in a patient with secondary hyperparathyroidism. A case report

Background:

Secondary hyperparathyroidism is a frequent complication of chronic renal failure. Patients resistant to pharmacotherapy are candidates for parathyroidectomy. Invasiveness of surgical treatment can be minimized by precise preoperative localization of parathyroid glands. Imaging modalities routinely used for this purpose are ultrasonography and MIBI-Tc99m scintigraphy.

Case Report:

Our case report shows advantages of co-registered computer tomography and conventional SPECT imaging (SPECT/CT) in a patient with advanced secondary hyperparathyroidism successfully treated with surgery.

Results:

Hybrid SPECT/CT parathyroid imaging enables better surgical planning and is superior to conventional scintigraphy.

Virtual neck exploration: a new method for localizing abnormal parathyroid glands

BACKGROUND DATA

Computed tomography (CT) together with 99mTc-sestamibi single photon emission computed tomography (MIBI-SPECT) image fusion (CT-MIBI-SPECT image fusion) allows virtual exploration of the neck. The aim of this study was to evaluate whether CT-MIBI-SPECT image fusion is superior to MIBI-SPECT and CT in detecting abnormal parathyroid glands in patients with primary hyperparathyroidism.

METHODS

CT-MIBI-SPECT image fusion for preoperative localization was performed in 116 patients with primary hyperparathyroidism (pHPT). Both investigations were performed with reproducible fixation of the patient on a vacuum mattress. At a special work station the neck was virtually explored by viewing the CT images in all 3 dimensions. The MIBI-SPECT images were superimposed on underlying CT images. Only patients with single-gland disease were evaluated (pHPT: 112, persistent pHPT: 1, recurrent pHPT: 1, persistent secondary hyperparathyroidism: 1, tertiary HPT after kidney transplantation: 1). CT-MIBI-SPECT image fusion results were compared with those obtained with CT alone and MIBI-SPECT alone. The predicted positions were correlated with the intraoperative findings.

RESULTS

CT-MIBI-SPECT image fusion was able to predict the exact position of the abnormal gland in 102 (88%) of the 116 patients, whereas CT alone showed in 75 (65%) patients and MIBI-SPECT alone in 64 (55%) patients the exact position of the abnormal gland. Sixty-two patients underwent minimally invasive surgery, namely in 21 patients with a unilaterally focused approach and in 33 patients with a bilateral approach (27 of these underwent simultaneous thyroid resection). Sensitivity for CT-MIBI-SPECT image fusion was 88%, for CT alone 70%, and for MIBI-SPECT alone 59%. Specificity for CT-MIBI-SPECT image fusion was 99%, for MIBI-SPECT alone 95%, for CT alone 94%. Overall accuracy for CT-MIBI-SPECT image fusion was 97%, for CT alone 89%, for MIBI-SPECT 87%.

CONCLUSIONS

This study provides evidence that CT-MIBI-SPECT image fusion is superior to CT or MIBI-SPECT alone for preoperative localization of enlarged parathyroid glands in patients with single-gland primary hyperparathyroidism.

Discriminative power of three indices of renal calcium excretion for the distinction between familial hypocalciuric hypercalcaemia and primary hyperparathyroidism: a follow-up study on methods

BACKGROUND

Familial hypocalciuric hypercalcaemia (FHH) must be differentiated from primary hyperparathyroidism (PHPT) because prognosis and treatment differ. In daily practice this discrimination is often based on the renal calcium excretion or the calcium/creatinine clearance ratio (CCCR). However, the diagnostic performance of these variables is poorly documented.

AIM

To appraise the power of various simple biochemical variables to differentiate between FHH and PHPT using calcium sensing receptor (CASR) gene analysis and histopathological findings as gold standards.

DESIGN

Follow-up approach (direct design).

MATERIALS

We included 54 FHH patients (17 males and 37 females, aged 18-75 years) with clinically significant mutations in the CASR gene and 97 hypercalcaemic patients with histologically verified PHPT (17 males and 80 females, aged 19-86 years). All PHPT patients became normocalcaemic following successful neck exploration.

RESULTS

Based on receiver operating characteristic (ROC) curve analysis, the CCCR was only marginally better, as judged by the area under curve (AUC = 0.923 +/- 0.021 (SE)), than the 24-h calcium/creatinine excretion ratio (AUC = 0.903 +/- 0.027) and the 24-h calcium excretion (AUC = 0.876 +/- 0.029). However, overlap performance analysis disclosed that the CCCR included fewer patients with PHPT together with the FHH patients than the other two variables at different cut-off points. Based on the ROC curve, the optimal cut-off point for diagnosing FHH using CCCR was < 0.0115, which yielded a diagnostic specificity of 0.88 and a sensitivity of 0.80. Overlap analysis revealed that a cut-off point for CCCR at < 0.020 would sample 98% (53/54) of all patients with FHH and include 35% (34/97) of the PHPT patients.

CONCLUSION

Our results support the use of the CCCR as an initial screening test for FHH. We suggest a two-step diagnostic procedure, where the first step is based on the CCCR with a cut-off at < 0.020, and the second step is CASR gene analysis in patients with FHH or PHPT.