The diagnostic utility of computed tomography for preoperative localization in surgery for hyperparathyroidism

Gonioprobe, an Innovative Gamma-probe to Guide Parathyroid Radioguided Surgery: First Clinical Experiences with Navigator and Lock-ontarget Functions

BACKGROUND

Radioguided surgery represents a validated technique for the detection and the excision of abnormal parathyroid glands responsible for primary hyperparathyroidism (PHPT). To date little attention has been paid as to how the characteristics of gamma-probes can influence surgical procedure and time, thus having an impact on postoperative morbidity, hospitalization and costs.

METHODS

We designed a new prototype of gamma-probe, the Gonioprobe, and tested its clinical utility in the operating room. Gonioprobe, thanks to its 5 scintillating independent crystals, performs the dual function of Navigator and Lock-on-target. These characteristics allow the immediate guidance of the surgeon's hand towards the source with very high precision, and with a much higher spatial resolution than commercial probes. Gonioprobe was used during intervention to detect abnormal parathyroid tissue, and to ensure no radioactivity in surgery bed after adenoma removal.

RESULTS

We tested our gamma-probe on parathyroid adenomas particularly difficult to identify at a visual inspection due to anatomy modifications from previous neck surgery and/or characterized by uncommon localization. Moreover, parathyroid adenomas were hardly removable due to the proximity to the esophagus, neck vessels and/or recurrent laryngeal nerve (RLN). An intraoperative nerve monitoring system was used to protect the recurrent laryngeal nerve from injuries. Parathyroid hormone (PTH) assay and frozen biopsy confirmed the successful excision of the adenomas.

CONCLUSION

The intraoperative use of the innovative Gonioprobe along with the nerve monitoring system allowed an accurate and safe removal of parathyroid adenomas and offered a significant advantage by reducing surgical time and postoperative complications, as well as hospitalization and costs.

Revisiting a Case of Parathyroid Adenoma With Bilateral Staghorn Calculus

Parathyroid gland adenoma is responsible for approximately 80%-85% cases of primary hyperparathyroidism. Although not much is diagnostic on clinical examination, the blood investigations of the patients reveal raised serum calcium and serum parathyroid hormone levels. We present a case of chronic kidney disease with bilateral staghorn calculi and a right parathyroid adenoma localized on ultrasonography. Parathyroid adenoma was surgically excised by minimally invasive parathyroidectomy.

Preoperative localization modalities in primary hyperparathyroidism: Correlation with postoperative cure

BACKGROUND

Accurate preoperative localization is critical to the success of minimally invasive parathyroidectomy. This investigation aimed to assess the correlation among preoperative imaging results, intraoperative findings, and postoperative cure rates in patients undergoing operation for primary hyperparathyroidism.

METHODS

A retrospective review of all patients who underwent operation for primary hyperparathyroidism between June 2010 and March 2016 was performed.

RESULTS

During the study period, 398 patients underwent parathyroidectomy. The overall cure rate was 97.5%. The ultrasonography performed by the surgeon was superior to the ultrasonography performed by the radiologist and to the sestamibi scan in lateralizing the adenoma correctly (80% vs 62% vs 70%, P < .001, respectively), and had the greatest sensitivity (93%) and accuracy (80%) among all tests (P < .001). Age ≥65 was found to be associated with lesser cure rates (94% vs 99.2%, P = .003). The number of positive preoperative studies correlated with cure rate, ranging from 80% for patients with 0 positive studies, to 100% in those with 4 positive studies (P = .0004). In patients with a negative sestamibi and an ultrasonography performed by the radiologist, there was no significant difference in the cure rates among those with no preoperative computed tomography, a positive preoperative computed tomography, or a negative preoperative computed tomography.

CONCLUSION

An ultrasonography performed by an experienced surgeon is an extremely valuable preoperative localization modality. The cure rate obtained is proportional to the number of positive imaging studies. In patients with negative ultrasonography performed by a nonexperienced radiologist and a negative sestamibi scan, the performance of computed tomography does not seem to increase cure rate. Patients with no positive preoperative scans represent a challenging subgroup, with cure rates of approximately 80%.

Diagnostic performance of computed tomography for parathyroid adenoma localization; a systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis of the sensitivity and positive predictive value (PPV) of CT for preoperative parathyroid localization in patients with primary hyperparathyroidism (pHPT), and subsequently compare the different protocols and their performance in different patient groups.

MATERIALS AND METHODS

We performed a search of the Embase, Pubmed and Cochrane Library databases to identify studies published between January 1, 2000 and March 31, 2016 investigating the diagnostic value of CT for parathyroid localization in patients with biochemical diagnosis of pHPT. Performance of CT was expressed in sensitivity and PPV with pooled proportion using a random-effects model. Factors that could have affected the diagnostic performance were investigated by subgroup analysis.

RESULTS

Thirty-four studies evaluating a total of 2563 patients with non-familial pHPT who underwent CT localization and surgical resection were included. Overall pooled sensitivity of CT for localization of the pathological parathyroid(s) to the correct quadrant was 73% (95% CI: 69-78%), which increased to 81% (95% CI: 75-87%) for lateralization to the correct side. Subgroup analysis based on the number of contrast phases showed that adding a second contrast phase raises sensitivity from 71% (95% CI: 61-80%) to 76% (95% CI: 71-87%), and that adding a third phase resulted in a more modest additional increase in performance with a sensitivity of 80% (95% CI: 74-86%).

CONCLUSION

CT performs well in localizing pathological glands in patients with pHPT. A protocol with two contrast phases seems to offer a good balance of acceptable performance with limitation of radiation exposure.

Performance of magnetic resonance imaging in the evaluation of first-time and reoperative primary hyperparathyroidism

BACKGROUND

Preoperative imaging in patients with primary hyperparathyroidism and a previous parathyroid operation is essential; however, performance of conventional imaging is poor in this subgroup. Magnetic resonance imaging appears to be a good alternative, though overall evidence remains scarce. We retrospectively investigated the performance of magnetic resonance imaging in patients with and without a previous parathyroid operation, with a separate comparison for dynamic gadolinium-enhanced magnetic resonance imaging.

METHODS

All patients undergoing magnetic resonance imaging prior to parathyroidectomy for primary hyperparathyroidism (first time or recurrent) between January 2000 and August 2015 at a high-volume, tertiary care, referral center for endocrine operations were included. We compared the sensitivity and positive predictive value of magnetic resonance imaging with conventional ultrasound and sestamibi on a per-lesion level.

RESULTS

A total of 3,450 patients underwent parathyroidectomy, of which 84 patients with recurrent (n = 10) or persistent (n = 74) disease and 41 patients with a primary operation were included. Magnetic resonance imaging had a sensitivity and positive predictive value of 79.9% and 84.7%, respectively, and performance was good in both patients with and without a previous parathyroid operation. Adding magnetic resonance imaging to the combination of ultrasound and sestamibi resulted in a significant increase in sensitivity from 75.2% to 91.5%. Dynamic magnetic resonance imaging produced excellent results in the reoperative group, with sensitivity and a positive predictive value of 90.1%.

CONCLUSION

Technologic advances have enabled faster and more accurate magnetic resonance imaging protocols, making magnetic resonance imaging an excellent alternative modality without associated ionizing radiation. Our study shows that the sensitivity of multimodality imaging for parathyroid adenomas improved significantly with the use of conventional and dynamic magnetic resonance imaging, even in the case of recurrent or persistent disease.

Sporadic multiple parathyroid gland disease--a consensus report of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Sporadic multiglandular disease (MGD) has been reported in literature in 8-33 % of patients with primary hyperparathyroidism (pHPT). This paper aimed to review controversies in the pathogenesis and management of sporadic MGD.

METHODS

A literature search and review was made to evaluate the level of evidence concerning diagnosis and management of sporadic MGD according to criteria proposed by Sackett, with recommendation grading by Heinrich et al. and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled 'Hyperparathyroidism due to multiple gland disease: An evidence-based perspective'.

RESULTS

Literature reports no prospective randomised studies; thus, a relatively low level of evidence was achieved. Appropriate surgical therapy of sporadic MGD should consist of a bilateral approach in most patients. Unilateral neck exploration guided by preoperative imaging should be reserved for selected patients, performed by an experienced endocrine surgeon and monitored by intraoperative parathormone assay (levels of evidence III-V, grade C recommendation). There is conflicting or equally weighted levels IV-V evidence supporting that cure rates can be similar or worse for sporadic MGD than for single adenomas (no recommendation). Best outcomes can be expected if surgery is performed by an experienced parathyroid surgeon working in a high-volume centre (grade C recommendation). Levels IV-V evidence supports that recurrent/persistence pHPT occurs more frequently in patients with double adenomas hence in situations where a double adenoma has been identified, the surgeon should have a high index of suspicion during surgery and postoperatively for the possibility of a four-gland disease (grade C recommendation).

CONCLUSIONS

Identifying preoperatively patients at risk for MGD remains challenging, intraoperative decisions are important for achieving acceptable cure rates and long-term follow-up is mandatory in such patients.

Radioguided Parathyroidectomy with Portable Mini Gamma-Camera for the Treatment of Primary Hyperparathyroidism

Background. A proper localisation of pathological parathyroid glands is essential for a minimally invasive approach in the surgical treatment of primary hyperparathyroidism (PHP). The recent introduction of portable mini gamma-cameras (pMGCs) enabled intraoperative scintigraphic scanning. The aim of our study is to evaluate the efficacy of this new method and compare it with the preoperative localisation surveys. Methods. 20 patients were studied; they were evaluated preoperatively by neck ultrasound and (99mm)Tc-sestaMIBI-scintigraphy and intraoperatively with the pMGC IP Guardian 2. The results obtained from the three evaluations were compared. Results. The pMGC presented a sensitivity of 95%, a specificity of 98.89%, and a diagnostic accuracy of 98.18%, which were higher than those of preoperative ultrasound (sensitivity 55%; specificity 95%; diagnostic accuracy 87%) and scintigraphy with (99mm)Tc-sestaMIBI (sensitivity 73.68%; specificity 96.05%; diagnostic accuracy 91.58%). Conclusions. The pMGC can be used effectively as an intraoperative method to find the correct location of the pathological parathyroid glands. The pMGC is more reliable than the currently used preoperative and intraoperative localisation techniques.

Imaging techniques in parathyroid surgery for primary hyperparathyroidism

As more patients present with the incidental diagnosis of primary hyperparathyroidism due to biochemical screening, treatment guidelines have been developed for the treatment of hyperparathyroidism. Management of primary hyperparathyroidism has evolved in recent years, with considerable interest in minimally invasive approaches. Successful localization of the diseased gland(s) by nuclear imaging and anatomical studies, along with rapid intraoperative parathyroid hormone assay, has allowed for focused and minimally invasive surgical approaches. Patients in whom the localization studies have identified single-gland adenoma or unilateral disease are candidates for such focused approaches instead of the traditional approach of bilateral exploration. These imaging techniques have also been critical in the successful management of patients with persistent or recurrent disease.

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.

Parathyroid localization with modified 4D-computed tomography and ultrasonography for patients with primary hyperparathyroidism

OBJECTIVES

In this article, we report our decade-long experience in using modified 4D-computed tomography in combination with ultrasonography (Mod 4D-CT/US) to localize abnormal parathyroid glands in patients with primary hyperparathyroidism.

STUDY DESIGN

Retrospective medical record review at a university-based academic medical center.

METHODS

Patients with primary hyperparathyroidism who underwent a Mod 4D-CT/US and parathyroidectomy between January 1998 and May 2009 were included in the study. Results from preoperative localization studies were compared with operative findings, pathologic data, and biochemical measurements to assess the sensitivity and specificity as well as the positive and negative predictive values of Mod 4D-CT/US.

RESULTS

Mod 4D-CT/US demonstrated 94% sensitivity and 96% specificity when these imaging studies were used to lateralize the hyperfunctioning parathyroid glands to one side of the neck. In regard to localizing abnormal parathyroid glands to a specific quadrant of the neck (i.e., right-left; superior-inferior), the sensitivity and specificity of Mod 4D-CT/US was 82% and 93%, respectively. Mod 4D-CT/US had a 92% positive predictive value for single-gland disease and 75% for multigland disease. The negative predictive value for single and multigland disease (MGD) were 73% and 92%, respectively.

CONCLUSIONS

Mod 4D-CT/US provides excellent sensitivity and specificity in terms of localizing abnormal parathyroid glands to the correct side and quadrant in patients with primary hyperparathyroidism, and it correctly identifies many patients with MGD.

Financial and clinical implications of low-energy CT combined with 99m Technetium-sestamibi SPECT for primary hyperparathyroidism

BACKGROUND

(99m)Technetium-sestamibi hybrid SPECT/CT has been favored over conventional SPECT in preoperative evaluation of primary hyperparathyroidism (PHPT) patients. However, the financial implications of CT-image acquisition have never before been published. This prompted us to perform a cost analysis of the aforementioned nuclear procedures.

METHODS

A total of 55 PHPT patients operated on between 2004 and 2009 were studied. Overall, 27 patients underwent SPECT and 28 SPECT/CT. Localization results, as well as diagnostic and clinical cost variations between SPECT and SPECT/CT patients, were compared.

RESULTS

SPECT/CT revealed higher sensitivity than SPECT (96.7 vs 79.3%; P = .011), as well as higher specificity (96.4 vs 82.4%; P = .037) and positive predictive value (PPV) (96.7 vs 83%; P = .038) for correctly identifying the neck-side affected by PHPT. Likewise, SPECT/CT disclosed higher sensitivity (86.7 vs 61.1%; P < .0001), specificity (97.4 vs 90%; P = .022), and PPV (86.7 vs 65.7%; P = .0001) for correct neck-quadrant identification. The mean operative time decreased from 62 min following SPECT to 36 min following SPECT/CT (P < .0001), yielding a mean surgical expense saving of 109.9 <euro>/patient (updated at 2009/2010 billing database). SPECT/CT actually ensures a mean expenditure reduction of 98.7 <euro>/patient (95% CI: 47.96 <euro>-149.42 <euro>), diagnostic costs variation amounting to 11.2 <euro>/procedure.

CONCLUSIONS

SPECT/CT ensures better focus for the surgical exploration, shortens surgical times, and eventually cuts costs when used for localization of parathyroid adenomas.

Efficacy of 4D-CT preoperative localization in 2 patients with MEN 2A

Multiple endocrine neoplasia type 2A (MEN2A) is an autosomal dominant syndrome that is associated with hyperparathyroidism in 20% to 30% of adult gene carriers. The appropriate surgical management of these patients remains in question. Approaches to this disease range from selective gland resection to a subtotal parathyroidectomy with or without autotransplantation. Despite surgical intervention, disease recurrence is problematic. Surgical management of patients found to have recurrence relies on localizing the anatomic location of the hyperfunctional gland(s). The primary imaging modality for localization of hyperfunctioning parathyroid glands is technetium 99m sestamibi single photon emission computed tomography (SPECT). Although sestamibi imaging has a sensitivity of 60% to 90%, specific anatomic detail is not always present by this imaging modality. Four-dimensional computed tomography (4D-CT) scans allow localization of ectopic parathyroid glands and autotransplanted parathyroid tissue, and they provide the anatomic detail necessary for decisions about appropriate surgical management. Another benefit of the 4D-CT scan is that enhancement characteristics, which are determined by contrast opacification of the hyperfunctional parathyroid tissue over 4 phases of the scan, correlate with metabolic activity. We recommend the use of 4D-CT scanning because of its capacity to identify hyperfunctional parathyroid glands and to provide anatomic information important in preoperative planning.

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

PURPOSE

This study was performed to evaluate the accuracy of multidetector computed tomography (MDCT) in detecting parathyroid lesions in patients with primary hyperparathyroidism.

MATERIALS AND METHODS

We included 60 patients with primary hyperparathyroidism. Preoperative first-line examinations revealed negative and doubtful ultrasound (US) findings in 34 and 26 cases, respectively, and negative, doubtful and positive scintigraphic findings in 19, 20 and 21 cases, respectively. CT findings were compared with the surgical results.

RESULTS

CT examination was positive in 35 cases, negative in 15 cases and doubtful in ten cases. Forty out of 60 patients underwent surgery, and 39 lesions (37 adenomas, two primary hyperplasias) were identified. Surgery was negative in two cases. In eight cases, lesions had ectopic location. Surgery confirmed the CT findings in 23 positive cases. In 8/10 doubtful cases, surgery confirmed the location of the lesion in five cases, identified the ectopic location of lesions in two cases, and was negative in one case. In 9/15 cases with negative CT findings, surgery identified the lesion in eight cases. Sensitivity, specificity and diagnostic accuracy values were 78%, 25% and 73%, respectively.

CONCLUSIONS

MDCT is an accurate second-line diagnostic technique in the detection of parathyroid lesions, allowing exploration of the entire cervical and mediastinal regions.

Parathyroid imaging: technique and role in the preoperative evaluation of primary hyperparathyroidism

OBJECTIVE

This article discusses the commonly used techniques for imaging the parathyroid glands and their role in the preoperative evaluation of patients with primary hyperparathyroidism.

CONCLUSION

The importance of sonography and sestamibi scintigraphy in the preoperative evaluation of patients with primary hyperthyroidism has increased with the adoption of minimally invasive parathyroidectomy techniques at most medical centers. When the results of these studies are concordant, the cure rates of minimally invasive surgery equal those of traditional bilateral neck exploration.

High resolution MRI in the detection of an intrathymic parathyroid adenoma

The most common cause of primary hyperparathyroidism is parathyroid adenoma. Of these, up to 20% have been reported to be in ectopic locations. Multiple imaging techniques have been utilized in the detection of ectopic adenoma and are discussed. We report on a case of an intrathymic parathyroid adenoma that was detected through the novel use of a breast coil in performing a high resolution MRI. The accurate localization permitted minimally invasive surgery, obviating morbidity associated with a sternotomy.