Comparison of histological findings and parathyroid scintigraphy in hemodialysis patients with secondary hyperparathyroid glands

Evaluation of Imaging Findings in Patients with Pretransplant and Posttransplant Tertiary Hyperparathyroidism

OBJECTIVES

Tertiary hyperparathyroidism, characterized by autonomous overproduction of parathyroid hormone, can be seen in patients with long-standing secondary hyperparathyroidism (pretransplant) or after renal transplant (posttransplant). Parathyroid scintigraphy and ultrasonography are the most commonly used imaging procedures for the preoperative localization of abnormal parathyroid glands. We aimed to evaluate imaging findings in pretransplant and posttransplant tertiary hyperparathyroidism.

MATERIALS AND METHODS

This study included 32 patients with pretransplant tertiary hyperparathyroidism and 20 patients with posttransplant tertiary hyperparathyroidism. On parathyroid scintigraphy with technetium-99m sestamibi, early-phase and latephase images were acquired. Images were evaluated for the presence and the number of active foci and the degree of uptake on the late-phase image. The existence of an autonomous gland was based on latephase retention and was scored from 0 to 2 (retention score). On ultrasonography, the criteria threshold for autonomy was the maximum length of the largest gland ≥10 mm (ultrasonography score).

RESULTS

On parathyroid scintigraphy, the most commonly observed pattern in the pretransplant group was positivity in ≥3 glands, and in the posttransplant group the most commonly observed pattern was positivity in 1 to 2 glands. In pretransplant and posttransplant groups, the criteria threshold for the presence of an autonomous parathyroid gland on parathyroid scintigraphy (grade 2 retention) was met in 26 (81%) and 9 (45%) patients and on ultrasonography in 25 (78%) and 10 (50%) patients, respectively. In the whole group of patients (n = 52), correlation existed between ultrasonography score and retention score. Glandular weight was correlated with both retention score and ultrasonography score.

CONCLUSIONS

Higher numbers of detectable glands and the presence of parathyroid autonomy were more common in the pretransplant group. This might be explained by parathyroid gland involution after transplant. The results may also suggest that factors other than autonomy are responsible for posttransplant tertiary hyperparathyroidism.

Diagnostic performance of planar scintigraphy using ⁹⁹mTc-MIBI in patients with secondary hyperparathyroidism: a meta-analysis

OBJECTIVE

Parathyroid scintigraphy using (99m)Tc-MIBI is not currently considered a valuable diagnostic tool for the localization of involved glands in patients with secondary hyperparathyroidism (SHPT). However, published data about its diagnostic accuracy are discordant and a meta-analysis about this topic is still lacking. The aim of our study is to meta-analyze the published data about the diagnostic performance of (99m)Tc-MIBI parathyroid scintigraphy in patients with SHPT.

METHODS

A comprehensive computer literature search of studies published in PubMed/MEDLINE, Scopus and Embase databases through September 2011 and regarding the diagnostic accuracy of (99m)Tc-MIBI parathyroid scintigraphy in patients with SHPT was carried out. Only articles in English language in which at least 10 patients with SHPT underwent planar (99m)Tc-MIBI parathyroid scintigraphy were selected. Pooled sensitivity, pooled specificity and area under the ROC curve on a per lesion-based analysis were calculated to measure the diagnostic accuracy of (99m)Tc-MIBI parathyroid scintigraphy in SHPT patients.

RESULTS

Twenty-four studies comprising 471 patients were included in this meta-analysis. The pooled sensitivity and specificity of (99m)Tc-MIBI parathyroid scintigraphy in detecting hyperplastic glands in SHPT patients were 58 % [95 % confidence interval (95 % CI) 52-65 %] and 93 % (95 % CI 85-100 %), respectively, on a per lesion-based analysis. Area under ROC curve was 0.75.

CONCLUSIONS

In patients with SHPT and diffuse or nodular hyperplasia, planar parathyroid scintigraphy using (99m)Tc-MIBI has demonstrated an inadequate diagnostic accuracy. Therefore, it should not be considered as a first-line diagnostic imaging method in the pre-surgical detection of hyperplastic parathyroid glands.

Usefulness of preoperative Tc-mibi parathyroid scintigraphy in secondary hyperparathyroidism

BACKGROUND AND AIMS

The usefulness of Tc-mibi parathyroid scintigraphy (Tc-PS) in planning parathyroidectomy for secondary hyperparathyroidism is not well known. The aim of this study was to review our experience with Tc-PS concerning: (1) the identification of hyperplastic glands, (2) detection of major ectopias and (3) prevention of recurrences.

PATIENTS AND METHODS

Thirty-three consecutive patients undergoing first-time subtotal parathyroidectomy for renal hyperparathyroidism had a dual-phase planar Tc-PS performed, and glands were classified as detected, weak, or not detected. The number and position of visualized glands were determined. Parathyroid weight, histology, and their relationship to Tc-PS were recorded after surgery.

RESULTS

Of 132 potential glands, 48 (35%) were localized on the Tc-PS and 128 (96.9%) were identified intraoperatively. Tc-PS positive/weak glands were heavier than nonlocalized glands. Tc-PS contributed to successful surgery in four patients with a single difficult gland each (three retrieved from the neck and one--fifth gland--requiring mediastinotomy). There was one persistence (3%) because of a missed fourth undescended inferior parathyroid gland. Two recurrences 2 years after surgery were due to a fifth thoracic gland not shown in the preoperative Tc-PS.

CONCLUSIONS

Preoperative Tc-PS helped in the intraoperative identification of moderate or major ectopias in 4/33 patients but was not useful to prevent recurrences from highly ectopic glands not visualized before first-time surgery.

Valor de la cirugía radioguiada con 99mTc-MIBI sensibilizada con dobutamina en el hiperparatiroidismo secundario persistente

99mTc-MIBI is a radiopharmaceutical that has been successfully used for the detection of hyperfunctioning parathyroid glands and for radioguided surgery techniques. We report on the case of a 55 year old woman in hemodialysis, with secondary persistent hyperparathyroidism after total parathyroidectomy. The conventional double-phase 99mTc-MIBI parathyroid scintigraphy was negative. The study was repeated after sensibilization with intravenous low-dose dobutamine showing an area of increased focal uptake in the lower cervical region. With this finding, radioguided 99mTc-MIBI surgery was performed after dobutamine administration, using a hand held gamma probe. The technique was considered successful with the resection of parathyroid cervical tissue which was further confirmed as nodular hyperplasia. We conclude that this methodology has the potential of being a an useful tool for the intraoperative localization of remanent tissue in patients with secondary persistent/recurrent hyperparathyroidism.

Sestamibi Scintigraphy, Topography, and Histopathology of Parathyroid Glands in Secondary Hyperparathyroidism

BACKGROUND

Several imaging techniques presently are available to assess the location of hyperplastic parathyroid glands. The purpose of the present study is to assess the place of dual-phase technetium Tc 99m-sestamibi (MIBI) scintigraphy in the preoperative localization of hyperplastic parathyroid glands in patients with severe secondary hyperparathyroidism (SHPT).

METHODS

We studied 35 consecutive adult white hemodialysis patients undergoing a first parathyroidectomy after performing MIBI scintigraphy. Hyperplasia of the parathyroid glands was classified as diffuse (DH) or nodular (NH). Statistical analysis was conducted by comparing patients with MIBI-negative (no focal area of increased uptake) with MIBI-positive (> or = 1 focal area of increased uptake) results and stratifying parathyroid glands according to location (superior and inferior).

RESULTS

MIBI scintigraphy showed focal areas of increased uptake in at least 1 gland in 25 patients (71.4%). Total number of focal areas of increased uptake was 42 of 121 glands removed (sensitivity, 34.7%; specificity, 100%). One hundred one glands showed NH and 20 glands showed DH. The 25 patients with MIBI-positive results had 85 pathological glands removed, and the 10 patients with MIBI-negative results had 36 pathological glands removed: in the former, most glands showed NH (77 of 85 glands; 90.6%), and in the latter, 24 of 36 glands showed NH (66.7%; P = 0.004 at chi-square test). The sensitivity of MIBI scintigraphy for distinguishing specific subtypes of hyperplasia was 37.6% (38 of 101 glands) for NH and 20.0% (4 of 20 glands) for DH (P = 0.0005). The following values were significantly greater in inferior compared with superior glands: (1) estimated weight (2.1 +/- 0.8 versus 1.6 +/- 1.2 g; P = 0.04), (2) percentage of MIBI positivity (34 of 42 inferior glands [80.9%] versus 8 of 42 superior glands [19.1%]; P = 0.0001), and (3) percentage of localization permitted by MIBI scintigraphy (34 of 63 inferior glands [54.0%] versus 8 of 58 superior glands [13.8%]; P = 0.0001). Thus, NH, although equally distributed between inferior (53 of 63 glands) and superior (48 of 58 glands) glands, showed a percentage of MIBI positivity significantly greater in inferior (34 of 53 glands [64.1%]) compared with superior glands (8 of 48 glands [16.7%]; P = 0.0001).

CONCLUSION

MIBI scintigraphy did not show high sensitivity in identifying hyperplastic glands, although it was able to identify those with NH better than those with DH. Thus, MIBI scintigraphy has limited value preoperatively for patients with SHPT. Estimated weight, percentage of MIBI positivity, and percentage of localization permitted by MIBI scintigraphy were significantly greater in inferior glands.