Multidetector CT in diagnostic work-up of patients with primary hyperparathyroidism

A new tool for diagnosing parathyroid lesions: angio plus ultrasound imaging

Background

Our aim was to examine the potential value of angio plus ultrasound imaging in diagnosing parathyroid lesions. Angio plus ultrasound imaging uses a new paradigm in Doppler performance, which allows for a better detection of flow in small vessels while maintaining workflow of conventional color flow imaging characteristics.

Methods

Thirty parathyroid lesions, composed of 26 histopathologically diagnosed adenoma and 4 hyperplasia (two hyperplasia in the same patient), from 29 consecutive patients (6 men and 23 women; median age: 53 years, range: 25-78 years) were evaluated using both color Doppler and angio plus ultrasound imaging. The polar vessel (visible or invisible), number and distribution (peripheral, central, and both) of blood flow signals were compared between the two techniques.

Results

On color Doppler, the polar vessel was visible in 6 (20%) lesions. The median number of blood flow signals was 6 [3-23]. The distribution of peripheral, central and both was shown in 4 (13.3%), 9 (30%), and 15 (50%) lesions respectively, and no blood signals was shown in 2 (6.7%) lesions. On angio plus ultrasound imaging, the polar vessel was visible in 16 (53.3%) lesions. The median number of blood flow signals was 3 [0-18]. The distribution of peripheral, central and both was shown in 1 (3.3%), 4 (13.3%), and 25 (83.3%) lesions respectively. There was significant difference between color Doppler and angio plus ultrasound imaging in the detection of the polar vessel, number and distribution of blood flow signals.

Conclusions

The typical polar vessel and increased vascularity commonly associated with parathyroid lesions may be obtained with angio plus ultrasound imaging. Angio plus ultrasound imaging can improve the detection rate and distribution characteristics of blood flow signals of parathyroid lesions. Further research is needed to clarify the clinical meaning of increased blood flow information, such as the differentiation of parathyroid lesions from other lesions.

Microvascular clamp technique as a reversible simulation of parathyroid gland excision

INTRODUCTION

This study demonstrates the effectiveness of a microvascular clamp to simulate parathyroid adenoma excision with respect to intraoperative parathyroid hormone (ioPTH) changes in vivo.

METHODS

Cases in which microvascular clamps were employed intraoperatively in conjunction with intraoperative parathyroid hormone(ioPTH) assays were reviewed. ioPTH values were recorded throughout these procedures to assess the efficacy and reversibility of tissue ischemia using microvascular clamps.

RESULTS

Application of a microvascular clamp across the vascular pedicle of a parathyroid adenoma resulted in a significant ioPTH drop in 95% of cases (N = 20). Removal of the clamp resulted in complete or partial rebound of ioPTH in 90% of cases (N = 20).

CONCLUSION

The use of a microvascular clamp to temporarily occlude a parathyroid gland's vascular pedicle is an effective simulation of gland excision with respect to ioPTH changes. Rebound of ioPTH levels after clamp removal demonstrates that this technique is generally reversible.

LEVEL OF EVIDENCE

2b, Retrospective cohort study.

Preoperative Localization of Parathyroid Adenomas Using 4-Dimensional Computed Tomography: A Pictorial Essay

Accurate preoperative localization is the key to successful parathyroid surgery in the era of minimally invasive parathyroid surgery. This article presents and discusses the embryologic basis of parathyroid gland and ectopic location and different imaging modalities helpful in diagnosing and localizing parathyroid adenomas and/or hyperplasia. We also aim to review the current surgical concepts in treatment of parathyroid adenomas and/or hyperplasia, the utility of 4-dimensional computed tomography for accurate preoperative localization of hyperfunctioning parathyroid glands, imaging classification of adenomas and/or hyperplasia, and, finally, present some of the limitations of 4-dimensional computed tomography.

The Utility of Multidetector Computed Tomography for Detection of Parathyroid Disease in the Setting of Primary Hyperparathyroidism

Purpose

The aim of this study was to evaluate the accuracy of multidetector computed tomography (MDCT) in the detection of parathyroid adenoma and hyperplasia in the setting of primary hyperparathyroidism.

Methods

Records of 48 patients with biochemically confirmed primary hyperparathyroidism, who underwent preoperative imaging with 16- or 64-slice contrast-enhanced MDCT and subsequent successful parathyroidectomy over a 3-year period, were reviewed. Two radiologists, blinded to the operative and histologic findings, independently evaluated multiplanar computed tomographic images for all patients.

Results

On pathologic examination, 63 abnormal glands were confirmed in 41 female and 7 male patients (mean age, 63 years). Of the 63 abnormal glands, 40 were adenomatous and 23 were hyperplastic. MDCT demonstrated an 88% (95% confidence interval [CI], 77%–99%) positive predictive value for localizing abnormal hyperfunctioning parathyroid glands. The sensitivity of MDCT in detecting single-gland disease was 80% (95% CI, 68%–92%); whereas the specificity for ruling out hyperfunctioning parathyroid tissue, either adenomatous or hyperplastic, was 75% (95% CI, 51%–99%). The sensitivity for exclusively localizing parathyroid hyperplasia was 17% (95% CI, 2%–33%). The parathyroid adenomas were substantially larger and heavier than their hyperplastic counterparts, with an average weight of 1.51 g (range, 0.08–6.00 g) and 0.42 g (range, 0.02–2.0 g) for adenoma and hyperplasia, respectively.

Conclusions

Contrast-enhanced MDCT demonstrated an 88% positive predictive value for localizing adenomatous and hyperplastic parathyroid glands. The poor sensitivity for detection of multigland disease was likely a result of the smaller size and weight of the abnormal hyperplastic glands.

Optimizing the minimally invasive approach to mediastinal parathyroid adenomas

BACKGROUND

Patients with refractory hyperparathyroidism after neck exploration may have a mediastinal parathyroid gland that has not been identified reliably with a single radiologic study. We report 17 patients who underwent minimally invasive resection for mediastinal parathyroid adenomas after confirmatory multipoint radiologic imaging.

METHODS

Fifteen patients underwent thoracoscopic procedures and 2 patients underwent mediastinoscopic procedures for resection of suspected mediastinal parathyroid adenoma. Preoperative localizing studies included sestamibi scan, computed tomography scan of the neck and chest, and selective venous sampling of parathyroid hormone levels. Once a mediastinal location was determined, thoracoscopic or mediastinoscopic resection was performed. Successful removal of parathyroid tissue was confirmed with a 50% or greater reduction in intraoperative parathyroid hormone levels.

RESULTS

Parathyroid adenoma was resected in 88% of patients after the operation. The cure rate was 100% in patients with two or more concordant studies locating parathyroid tissue in the mediastinum and 60% in those with one positive study. The thoracostomy tube was removed on median postoperative day 1 (range, 0 to 2 days). Median hospital stay was 3 days (range, 2 to 7 days). The most common complication was temporary hypocalcemia, which occurred in 18% of patients.

CONCLUSIONS

Minimally invasive parathyroidectomy is an effective treatment of hyperparathyroidism caused by mediastinal parathyroid tissue. Targeted exploration depends on the guidance of preoperative localization studies and measurement of intraoperative parathyroid hormone levels to verify successful resection. Selective venous sampling and high-resolution computed tomography scanning can be helpful in patients with negative sestamibi scans.