Preoperative Parathyroid Localization Research Articles

Preoperative parathyroid localization. Relevance of MIBI SPECT-CT in adverse scenarios

PurposeSelective parathyroidectomy, the treatment of choice for primary hyperparathyroidism, requires precise preoperative localization. Our purpose was to compare the accuracy and concordance of pre-surgical MIBI parathyroid scintigraphy and ultrasonography, as well as to assess the relevance of hybrid acquisition (SPECT/CT) in compromised circumstances: low-weight or ectopic adenomas, coexisting thyroid disease and re-interventions. MethodsThe study included 223 patients with primary hyperparathyroidism operated in a single Surgical Unit from August 2016 to March 2021. Preoperative ultrasonography and double-phase MIBI were performed with early SPECT/CT acquisition. A minimally invasive surgical approach was initially attempted, except in patients with concomitant thyroid surgery or multiglandular parathyroid disease. ResultsSelective parathyroidectomy was accomplished in 179 patients (80.2%); cervicotomy and/or thoracoscopy in 44. Removal of the parathyroid lesion was achieved in 211 patients (94.6%), corresponding 204 (96.7%) to adenomas (37 ectopic). The cure rate was 94.2%. Preoperative MIBI SPECT/CT showed higher sensitivity and accuracy (84%; 80%) compared to ultrasound (72%; 71%), being more precise in defining the exact anatomical location (75.8% vs 68.7%). These differences reached statistical significance in ectopic glands. The existence of concomitant thyroid pathology did not decrease the sensitivity of SPECT/CT (84.2%). Mean parathyroid weight was 692.2mg (95%CI: 443.5-941) in MIBI-negative cases and 1145.9mg (95%CI: 983.6-1308.3) in MIBI-positive (p=0.001). Re-intervention was successful in the 8 patients with previous surgery. ConclusionMIBI SPECT/CT presents greater sensitivity, accuracy and anatomical precision than ultrasound for preoperative parathyroid localization, even in the case of ectopic glands or coexisting thyroid pathology. The weight of the pathological gland is a significantly limiting factor.

A-310 18F-FLUOROCHOLINE-PET/CT IS THE BETTER TOOL TO LOCALISE “NEGATIVE” PARATHYROID ADENOMAS – INTRAOPERATIVE CORRELATION AND 12 MONTH POSTOPERATIVE RESULTS

Abstract Background To characterise the diagnostic performance of 18F-Fluorocholine PET/CT (FCH-PET/CT) to localise parathyroid adenomas (PA) in primary hyperparathyroidism (pHPT) when ultrasound (US) and MIBI-Scan (MS) failed - intraoperative correlation and one year follow up. Methods Beginning in 07/2017 FCH-PET/CT was employed in patients with proven pHPT in whom US and MS delivered either incongruent or negative findings. All patients were offered cervical explorations with intraoperative PTH-monitoring (IO-PTH) and followed for 12 months postoperatively. Imaging results were correlated to operative findings and histopathologic reports and to short term biochemical outcome as well as one-year postoperative follow-up data. Results From 07/2017 to 11/2022, 1085 patients were operated for pHPT. In this period, 215 FCH-PET/CT were performed suggesting PA(s) in 176, 6 false positive, and 33 false negative (sensitivity 84.2%, PPV 96.7%). Of the 95 cases were US and MIBI both gave negative results, FCH-PET/CT accurately localised PA(s) to the respective side of the neck in all the 72 FEC-PET-positive cases (global sensitivity of 75.8%); and was negative in 23 (24.2%). In the 12-month postoperative follow up (currently matched by 61/95) there was no biochemical persistent disease. However, 3 patients exhibited PTH or calcium at the upper limit of norme, thus, a recurrence cannot be reliably excluded so far. Conclusion FCH-PET/CT allows for planned unilateral and focused as opposed to bilateral explorations, especially when preoperative parathyroid localisation with US and MiBI fails. We, therefore, suggest FCH-PET/CT as the preferred tool for the localisation of the “negative” PA.

Dual-phase computed tomography for localization of parathyroid lesions in children and adolescents with primary hyperparathyroidism

BackgroundChildhood and adolescent primary hyperparathyroidism (PHPT) is a rare disease caused by single adenomas in 65–94% of patients. In this patient group, there is no data on computed tomography (CT) for pre-operative parathyroid localization that may facilitate focused parathyroidectomy. MethodsTwo radiologists reviewed dual-phase (nonenhanced and arterial) CT images of twenty-three operated children and adolescents [20:single-gland disease(SGD), 3:multi-glandular disease(MGD)] with proven histopathological PHPT. Percentage arterial enhancement (PAE) was calculated as [100*{arterial-phase Hounsfield unit (HU)-nonenhanced phase HU}/nonenhanced HU] of the parathyroid lesion(s), thyroid, and lymph node. ResultsDual-phase CT lateralized 100%, localized to the correct quadrant/site 85% SGD (including 3/3 ectopic), and identified 1/3 MGD. PAE (cutoff ≥ 112.3%) was sensitive (91.3%) and specific (99.5%) in distinguishing parathyroid lesions from local mimics (P<0.001). The average effective dose was 3.16±1.01mSv, comparable to the planar/single photon emission CT (SPECT) Technetium 99m(Tc)-sestamibi and choline positron emission tomography (PET)/CT scans. Solid-cystic morphology identified in 4 patients harboring pathogenic germline variants (3:CDC73, 1:CASR) may serve as a radiological clue to molecular diagnosis. Nineteen out of 20 (95%) patients with SGD who had undergone single gland resection based on pre-operative CT findings were in remission over a median follow-up of 18 months. ConclusionAs most children/adolescents with PHPT have SGD, dual-phase CT protocols which reduce the effective radiation dose with high localization sensitivity for single parathyroid lesions may be a sustainable pre-operative imaging modality in this patient group.

PSUN76 Massive Four-Gland Parathyroid Hyperplasia: The Case of the Missing Glands

Abstract Introduction Parathyroid adenoma (PA) and parathyroid hyperplasia (PH) are common causes of primary hyperparathyroidism (PHPT) for which the only definitive treatment is surgical removal. Surgery is often preceded by imaging for localization, including by ultrasound (US), Sestamibi scan (MIBI), positron emission tomography/computer tomography (PET/CT), and four-dimensional computed tomography (4D-CT). While it is common for parathyroid pathology to not be visualized on imaging, non-visualization is more typical of adenomas and hyperplasia of smaller size. Clinical Case A 65-year-old male without history of kidney dysfunction or family history of parathyroid disease was referred to surgery for parathyroidectomy to manage longstanding PHPT. Serology showed a parathyroid hormone (PTH) level of 581 pg/mL (reference range: 12-65 pg/mL) and calcium of 11.8 mg/dL (reference range: 8.6-10.5 mg/dL). Preoperative parathyroid localization US revealed a large well-defined 1.5 cm PA. The patient underwent parathyroidectomy, which detected a large right inferior parathyroid gland, confirmed with pathology to be an atypical parathyroid adenoma weighing 1800 mg. Postoperative PTH level was 550 pg/mL and calcium was 12.6 mg/dL. MIBI did not display any definite parathyroid adenoma or ectopic parathyroid tissue. Further evaluation with PET/CT did not demonstrate any evidence of metabolically active residual or ectopic parathyroid adenoma or metastatic disease, and repeat US showed did not reveal evidence of any abnormal parathyroid tissue. Ultimately, 4D-CT detected a multiglandular parathyroid with a 1.8×1.4×3.0 cm right superior adenoma weighing approximately 3931 mg, 1.2×0.8×2.1cm left superior adenoma weighing approximately 1048 mg, and a 0.3×0.4×0.4cm left superior adenoma weighing approximately 25 mg. The patient underwent re-exploration parathyroidectomy with removal of the right superior adenoma weighing 3105 mg and left superior adenoma weighing 1100 mg. The remaining left inferior gland was biopsied and the majority of it was implanted into the arm. Repeat serology one week post-operatively showed improvement of PTH level to 5 pg/mL and of calcium to 8.9 mg/dL and serology one year post-operatively showed a PTH level of 82 pg/mL and a calcium of 9.4 mg/dL. Conclusion We present a patient with massive four-gland PH who initially presented with findings more typical of PA, but ultimately had additional hyperplasic glands that were identified after removal of the adenomatous gland. These glands were unusually large to be seen in PH and yet still be undetected on multiple imaging modalities; no previously reported non-ectopic hyperplastic glands of this size have been documented that were not detected on US or MIBI. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Preoperative parathyroid localization. Relevance of MIBI SPECT-CT in adverse scenarios

PurposeSelective parathyroidectomy, the treatment of choice for primary hyperparathyroidism, requires precise preoperative localization. Our purpose was to compare the accuracy and concordance of pre-surgical MIBI parathyroid scintigraphy and ultrasonography, as well as to assess the relevance of hybrid acquisition (SPECT/CT) in compromised circumstances: low-weight or ectopic adenomas, coexisting thyroid disease and re-interventions. MethodsThe study included 223 patients with primary hyperparathyroidism operated in a single Surgical Unit from August 2016 to March 2021. Preoperative ultrasonography and double-phase MIBI were performed with early SPECT/CT acquisition. A minimally invasive surgical approach was initially attempted, except in patients with concomitant thyroid surgery or multiglandular parathyroid disease. ResultsSelective parathyroidectomy was accomplished in 179 patients (80.2%); cervicotomy and/or thoracoscopy in 44. Removal of the parathyroid lesion was achieved in 211 patients (94.6%), corresponding 204 (96.7%) to adenomas (37 ectopic). The cure rate was 94.2%. Preoperative MIBI SPECT/CT showed higher sensitivity and accuracy (84%; 80%) compared to ultrasound (72%; 71%), being more precise in defining the exact anatomical location (75.8% vs 68.7%). These differences reached statistical significance in ectopic glands. The existence of concomitant thyroid pathology did not decrease the sensitivity of SPECT/CT (84.2%). Mean parathyroid weight was 692.2mg (95%CI: 443.5-941) in MIBI-negative cases and 1145.9mg (95%CI: 983.6-1308.3) in MIBI-positive (p=0.001). Re-intervention was successful in the 8 patients with previous surgery. ConclusionMIBI SPECT/CT presents greater sensitivity, accuracy and anatomical precision than ultrasound for preoperative parathyroid localization, even in the case of ectopic glands or coexisting thyroid pathology. The weight of the pathological gland is a significantly limiting factor.

Is preoperative parathyroid localization necessary for tertiary hyperparathyroidism?

BackgroundThe role of preoperative parathyroid localization for tertiary hyperparathyroidism(tHPT) is unclear. We reviewed our experience regarding the feasibility of parathyroidectomy without preoperative localization. MethodsThis is a retrospective study of renal allograft recipients who underwent parathyroidectomies (2001–2019). Patients with normal preoperative serum calcium and PTH levels or previous cervical operations were excluded. Patient demographics, laboratory results, radiology reports, pathology reports, and clinical notes were reviewed. Wilcoxon signed rank test, Mann-Whitney U test, Fisher's exact and Pearson chi-square analysis were used to compare patients with and without preoperative localization. ResultsOf the 118 patients, 25 patients(21.1%) had preoperative localization. Of the 36 ectopic glands recovered, 31(86.1%) were found without preoperative localization. All 118 patients achieved normocalcemia at the time these data were collected. There were no differences in surgical cure rate, recurrence rate, temporary hoarseness, or postoperative symptomatic hypocalcemia between the two groups. ConclusionsWe observed no differences in surgical cure rate, reoperation rate, or postoperative complications without preoperative localization. Under most circumstances, it is appropriate to perform parathyroidectomy for tHPT without localization.

Four-dimensional computed tomography (4D-CT) for preoperative parathyroid localization: A good study but are we using it?

BackgroundFour-dimensional computed tomography (4D-CT) scan to localize abnormal parathyroid glands is diagnostically superior to ultrasound (US) and sestamibi. The implementation of 4D-CT imaging is unknown. MethodsThe Collaborative Endocrine Surgery Quality Improvement Program (CESQIP) database from 2014 to 2018 was utilized. Patients with hyperparathyroidism undergoing an initial operation were included. The rate of US, sestamibi and 4D-CT performance was calculated for the entire study population, and for each institution. Results7,959 patients were included. In 311(3.9%) patients, no preoperative imaging was recorded. Of patients with imaging, US was performed in 6,872(86.3%), sestamibi in 5,094(64.0%), and 4D-CT in 1,630(20.4%). The combination of US and sestamibi was most frequent (3,855, 48.4%). Institutional rates of 4D-CT performance varied from 0.1% to 88.7%. ConclusionsOf the imaging modalities, 4D-CT was utilized least frequently and with greatest variability. Given the high accuracy of 4D-CT, efforts to reduce this variation may improve overall preoperative localization in patients with hyperparathyroidism.

Superior sensitivity of 18F-fluorocholine: PET localization in primary hyperparathyroidism

BackgroundPreoperative parathyroid imaging guides surgeons during parathyroidectomy. This study evaluates the clinical impact of 18F-fluorocholine positron emission tomography for preoperative parathyroid localization on patients with primary hyperparathyroidism. MethodsPatients with primary hyperparathyroidism and indications for parathyroidectomy had simultaneous 18F-fluorocholine positron emission tomography imaging/magnetic resonance imaging. In patients who underwent subsequent parathyroidectomy, cure was based on lab values at least 6 months after surgery. Location-based sensitivity and specificity of 18F-fluorocholine positron emission tomography imaging was assessed using 3 anatomic locations (left neck, right neck, and mediastinum), with surgery as the gold standard. ResultsIn 101 patients, 18F-fluorocholine positron emission tomography localized at least 1 candidate lesion in 93% of patients overall and in 91% of patients with previously negative imaging, leading to a change in preoperative strategy in 60% of patients. Of 76 patients who underwent parathyroidectomy, 58 (77%) had laboratory data at least 6 months postoperatively, with 55/58 patients (95%) demonstrating cure. 18F-fluorocholine positron emission tomography successfully guided curative surgery in 48/58 (83%) patients, compared with 20/57 (35%) based on ultrasound and 13/55 (24%) based on sestamibi. In a location-based analysis, sensitivity of 18F-fluorocholine positron emission tomography (88.9%) outperformed both ultrasound (37.1%) and sestamibi (27.5%), as well as ultrasound and sestamibi combined (47.8%). ConclusionLong-term results in the first cohort in the United States to use 18F-fluorocholine positron emission tomography for parathyroid localization confirm its utility in a challenging cohort, with better sensitivity than ultrasound or sestamibi.

Diagnostic Role of Four-Dimensional Computed Tomography for Preoperative Parathyroid Localization in Patients with Primary Hyperparathyroidism: A Systematic Review and Meta-Analysis.

We sought to systematically evaluate diagnostic performance of four-dimensional computed tomography (4D-CT) in the localization of hyperfunctioning parathyroid glands (HPGs) in patients with primary hyperparathyroidism (pHPT). We calculated the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratios (DOR) of 4D-CT on a per-lesion level, as well as pooled sensitivity and positive predictive value (PPV) on a per-patient level with 95% confidence intervals (CIs). Additionally, we plotted summary receiver operating characteristic (SROC) curves and evaluated the areas under the curves (AUC). A total of 16 studies were included in the analysis. Their pooled sensitivity, specificity, PLR, NLR, and DOR of 4D-CT on per-lesion level were 75% (95%CI: 66–82%), 85% (95%CI: 50–97%), 4.9 (95%CI: 1.1–21.3), 0.30 (95%CI: 0.19–0.45), and 17 (95%CI: 3–100), respectively, with an AUC of 81% (95%CI: 77–84%). We also observed heterogeneity in sensitivity (I2 = 79%) and specificity (I2 = 94.7%), and obtained a pooled sensitivity of 81% (95%CI: 70–90%) with heterogeneity of 81.9% (p < 0.001) and PPV of 91% (95%CI: 82–98%) with heterogeneity of 80.8% (p < 0.001), based on a per-patient level. Overall, 4D-CT showed moderate sensitivity and specificity for preoperative localization of HPG(s) in patients with pHPT. The diagnostic performance may improve with 4D-CT’s promotion to first-line use on a lesion-based level, further research is needed to confirm the results.

Implementation of a 4-dimensional computed tomography protocol for parathyroid adenoma localization

PurposeTo present the results of our implementation of a four-dimensional computed tomography- (4DCT) based parathyroid localization protocol for primary hyperparathyroidism at a safety net hospital. MethodsWe performed a retrospective review of all patients who underwent parathyroidectomy for primary hyperparathyroidism at Elmhurst Hospital Center from June 2016 – September 2019. Patients treated prior to the implementation of 4DCT during October 2018 served as historical controls for comparison. Imaging-related costs and hospital charges were obtained from the Radiology Department for each patient. ResultsForty-two patients underwent parathyroid surgery during the study period. Twenty patients had undergone 4DCT while 22 had nuclear medicine studies with or without ultrasonography. The sensitivity and specificity of 4DCT was 90.4% and 100% respectively, compared to 63% and 93.7% for nuclear imaging studies and 41% and 95% for ultrasound. The mean number of glands explored was significantly less in the 4DCT group, 1.8 ± 1.19 versus 2.77 ± 1.26 (p = 0.01). There was no increase in infrastructure or personnel costs associated with 4DCT implementation. Conclusions4DCT represents an increasingly common imaging modality for pre-operative parathyroid localization. Here we demonstrate that 4DCT is associated with a reduction in the number of glands explored and enables minimally invasive parathyroid surgery. 4DCT is a cost-effective and clinically sound localization study for parathyroid localization in an urban safety-net hospital.

Will 18F-fluorocholine PET/CT replace other methods of preoperative parathyroid imaging?

Primary hyperparathyroidism (PHPT) is a common endocrine disorder usually due to hyperfunctioning parathyroid glands (HPs). Surgical removal of the HPs is the main treatment for PHPT, making the correct detection and localization of HPs crucial to guiding targeted and minimally invasive surgical treatment in patients with PHPT. To date, different imaging methods have been used to detect and localize HPs, including radiology, nuclear medicine, and hybrid techniques. The present work discusses the role and value of different imaging methods in PHPT and, particularly, evaluates the potential role of 18F-fluorcholine PET/CT as a "one-stop-shop" method for preoperative parathyroid localization in patients with PHPT. Cervical ultrasound (US) and parathyroid scintigraphy using 99mTc-MIBI are the most commonly employed methods in clinical practice. More recently, four-dimensional computed tomography (4D CT) and positron emission tomography (PET) with radiolabeled choline have emerged as useful alternatives in cases of negative or discordant findings from first-line imaging methods. Due to the excellent diagnostic performance of radiolabeled choline PET/CT and the low radiation burden, this technique seems to be an ideal candidate to substitute current imaging procedures including US, MIBI scintigraphy, 4D CT and MRI and perform a fast and reliable "one-stop-shop" preoperative localization of HP in patients with PHPT, including challenging cases of postoperative persistent/recurrent disease.

Preoperative parathyroid localization does not improve surgical outcomes for patients with primary hyperparathyroidism

BackgroundMost patients with primary hyperparathyroidism undergo localization prior to operation with variable success. Therefore, in this study we investigated the safety of parathyroidectomy without imaging. MethodsA prospective database of 2057 surgical patients with primary hyperparathyroidism from 2001 to 2019 was reviewed. Patients were categorized by use of preoperative imaging (ultrasound, sestamibi, CT scan), pathology, and cure. Results1879 (91%) patients underwent preoperative imaging. CT scan was the most sensitive study (92%), though specificity was only 64%. Patients with imaging were older, had higher pre- and postoperative calcium, more likely to undergo unilateral exploration and have an adenoma (p < 0.001–0.038). No differences were seen in nerve injury (<1%), postoperative hypocalcemia (<1%), or cure rate. ConclusionsWhile localization may lead to minimally-invasive operations, we observed no differences in postoperative complications or cure rates in the hands of an experienced surgeon. Therefore, preoperative parathyroid localization does not improve outcomes for hyperparathyroidism and can be ordered sparingly.

MON-LB088 Comparative Study of Single Photon Emission Computed Tomography (SPECT)/CT Imaging Versus Combined Planar Technetium-99m Sestamibi -Ultrasonographic Imaging for Pre-Operative Parathyroid Localisation in Primary Hyperparathyroidism.

Primary hyperparathyroidism is the third most common endocrine disorder in the western world with an estimated prevalence of 1-4 per 1000.The only curative treatment is surgical resection. Minimally invasive surgical techniques are preferred over bilateral neck exploration due to reduced risk of surgical complications (1.2% vs 3%) and seven-fold shorter hospital stay with cost reduction of up to 50% (1); however this requires accurate preoperative localisation. Various imaging modalities evolved over time to identify pathological parathyroid glands pre-operatively. Imaging modality which is non-invasive, accurate and has minimal radiation exposure should be preferred as a first line option. Planar Technetium-99m Sestamibi scintigraphy coupled with Ultrasonography (MIBI/USS) has conventionally been used as the localisation study of choice. Single Photon Emission Computed Tomography (SPECT)/CT has been introduced recently and adopted by our centre as a first line investigation. The aim of the current study was to compare the accuracy of MIBI/USS versus SPECT/CT in localising pathological parathyroid glands preoperatively and assess the influence of imaging modality on surgical outcomes. A total of 135 patients with confirmed primary hyperparathyroidism were studied retrospectively in a tertiary centre over 24 months period. 61 patients underwent MIBI/USS and 74 had SPECT/CT as first line imaging. 82% of patients were female with mean age of 67 years. Preoperatively Sestamibi -SPECT/CT identified the laterality of the adenoma in 78.4% of cases, compared to 49.2% in MIBI/USS (p<0.001). Post operative surgical and histological concordance in terms of laterality and position (inferior or superior) of the hyper-functioning gland SPECT/CT (59.5%) was still superior compared to MIBI/USS (34.4%), p=0.04. There were two cases of intra-thyroidal adenoma of which both were identified by SPECT/CT. Additionally there were two cases of mediastinal parathyroid foci identified on SPECT/CT. None of the patients who underwent MIBI/USS had ectopic foci. Out of the 135 patients, 83.0% had a single parathyroid adenoma, 9.6% had single or multi-gland hyperplasia, 1.4% had ectopic parathyroid adenomas (n=1 mediastinal, n=1 thymus) and there were no cases of parathyroid carcinoma. 16 patients (22.5%) in the SPECT/CT group had bilateral neck exploration versus 24 (39.3%) in the MIBI/USS group (p = 0.04).There was no difference in length of hospital stay (average 1 day) between groups and no significant difference in post operative complications (laryngeal nerve palsy, post-operative hypocalcaemia) between the two groups . There was no statistically significant difference between cure rates with either modality of imaging MIBI/USS or SPECT/CT (93.4% and 93.1% respectively, p=0.93) (1).R.UDELSMAN. 656 consecutive explorations for primary hyperparathyroidism. Ann Surg. 2002;235(5):665-70 Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

99mTc-MIBI SPECT/CT imaging had high sensitivity in accurate localization of parathyroids before parathyroidectomy for patients with secondary hyperparathyroidism

Purpose: Accurate preoperative parathyroid localization is important for successful parathyroidectomy (PTX). The aim of our study was to investigate whether SPECT/CT has enhanced effect in preoperative localization of parathyroids.Methods: In our retrospective cohort study, we evaluated the effects of technetium-99m methoxyisobutylisonitrile-single-photon emission computed tomography/computed tomography (99mTc-MIBI SPECT/CT) on preoperative parathyroid localization for 645 secondary hyperparathyroidism (SHPT) patients. Among them, 569 successful PTX patients were divided into group A (received 99mTc-MIBI scintigraphy, n = 175) and group B (received 99mTc-MIBI scintigraphy and SPECT/CT imaging, n = 394). Sensitivity, specificity, and consistency of two imaging methods in preoperative localization of parathyroids were compared.Results: Overall sensitivity and consistency were higher in group B, while there was no difference in specificity between the two groups. In group A, the sensitivity of 99mTc-MIBI was 50.00%, 77.11%, 61.76%, and 76.54% in the right upper gland (RU), right lower gland (RL), left upper gland (LU), and left lower gland (LL) subgroups, while the consistency was 52.00%, 76.57%, 61.71%, and 75.43%, respectively. In group B, the sensitivity of 99mTc-MIBI with SPECT/CT was 69.39%, 90.03%, 78.07%, and 84.27%, and the consistency was 69.54%, 88.32%, 78.43%, and 84.26%, respectively. The sensitivity and consistency in lower glands were higher than in upper glands in both groups. Sensitivity for eutopic parathyroid was higher in group B, while there was no difference for ectopic parathyroid.Conclusions: 99mTc-MIBI SPECT/CT can increase the sensitivity and consistency of preoperative localization of eutopic parathyroid glands, and it can accurately locate ectopic parathyroid without sensitivity improvement.

Discussion of “Dual energy computed tomography should be the first line preoperative localization imaging test for primary hyperparathyroidism patients”

•Dual energy CT – first line preoperative parathyroid localization in hyperparathyroidism patients. •Dual energy CT and neck ultrasound – standard for surgical planning in hyperparathyroidism patients. •Dual energy CT – sensitive salvage localization test in hyperparathyroidism patients.

Dual Parathyroid Pathology; A Common Failure of Technetium-99 Sestamibi Scan for Preoperative Parathyroid Adenoma Localization

Dual Parathyroid Pathology; A Common Failure of Technetium-99 Sestamibi Scan for Preoperative Parathyroid Adenoma Localization

Preoperative parathyroid localization using joint planar imaging.

The conventional approach for preoperative parathyroid localization with the dual 99mTc-sestamibi (99mTc-MIBI) and 99mTc-pertechnetate (99mTcO4- ) scintigraphy technique obtains the differential image by subtracting images from the two scans; the former depicts both the thyroid and parathyroid glands while the latter depicts the thyroid only. In this study, we developed a novel method based on Poisson noise modeling and maximum-likelihood estimation to generate the differential image in an iterative fashion using both planar images jointly. We demonstrated improved performance of our joint method as compared with the subtraction method in both phantom and patient studies. In the phantom study, we acquired two noise-free planar datasets using 99mTc on an in-house thyroid phantom and a "lesion" bead (representing a parathyroid gland) with the same attenuation background as the thyroid phantom. These two planar datasets were combined and scaled to simulate noise-free clinical MIBI (four lesion-to-background contrast (LBC) values: 1.2, 1.3, 1.4 and 1.5), and 99mTcO4- datasets. One-hundred Poisson noise realizations were generated for each datasets. The mean and standard deviation (SD) of the lesion contrast in the differential images were computed for both the subtraction and the joint methods. We also applied both the subtraction and the joint methods to one parathyroid patient dataset. The voxel-wise mean-to-SD ratios in four hyperfunctioning parathyroid lesions were calculated. The phantom results showed that the joint method at the 50th iteration yielded a significant SD reduction compared with the subtraction method ranging from 20% to 45% (p <; 0.05). Similarly, the voxel-wise mean-to-SD ratios were substantially improved in the patient study from 0.40-1.60 (subtraction) to 2.68-3.16 (joint).

Evaluation of the radiation dose exposure and associated cancer risks in patients having preoperative parathyroid localization.

OBJECTIVE The study aimed to evaluate the total effective and organ absorbed radiation doses associated with three- and four-phase parathyroid computed tomography (CT) and sestamibi scans used for the preoperative localisation of parathyroid adenomas in a cohort of patients with primary hyperparathyroidism at a single institution. We aimed to assess the risk of cancer incidence for the organs demonstrating the highest absorbed doses for the different imaging techniques, and more specifically determine the risk for our cohort of patients. METHODS Fifty patients with primary hyperparathyroidism had both multiphase CT and sestamibi scans. The Imaging Performance Assessment of CT Scanners (ImPACT) calculator was used to estimate the patient-effective and organ-absorbed radiations doses for all the CT examinations. For sestamibi scans, the US Nuclear Regulatory Commission NUREG/CR-6345 publication was used to estimate the dose for each patient. The attributable risks of cancer were calculated using the Health Protection Agency HPA-CRCE-028 publication. RESULTS The mean patient total effective doses were 15.9%±2.8mSv, 20.2%±2.8 mSv and 5.6±0.24mSv for three-phase CT, four-phase CT and sestamibi examinations, respectively. In our cohort, the highest attributable lifetime risk was for lung cancer (0.03%) after multiphase CT. This compared with a tenfold lower risk for thyroid cancer (0.003%). After sestamibi, the highest risk was for colon cancer (0.06%). CONCLUSIONS Multiphase CT is associated with a higher radiation dose and thus a higher potential risk of cancer, but this risk is low in the older population that constituted the majority of our cohort.

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

Abstract purposeTo 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 methodsWe 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. ResultsThirty-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%). ConclusionCT 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.

Accuracy of 2-Phase Parathyroid CT for the Preoperative Localization of Parathyroid Adenomas in Primary Hyperparathyroidism.

Minimally invasive parathyroidectomy requires accurate preoperative localization of suspected adenomas, and multiphase CT allows adenoma characterization while providing detailed anatomic information. The purpose of this study was to assess the feasibility of a protocol using only arterial and venous phases to localize pathologic glands in patients with primary hyperparathyroidism. We identified 278 patients with primary hyperparathyroidism who had undergone 2-phase CT with surgical cure. All scans were read prospectively by board-certified neuroradiologists. A neuroradiology fellow retrospectively reviewed images and reports and classified suspected adenomas on the basis of anatomic location. Accuracy was determined by comparing imaging results with surgical findings. The ability of 2-phase CT to localize adenomas to 1 of 4 neck quadrants and lateralize them to the correct side was assessed. Accuracy of identifying multigland disease was also evaluated. In patients with single-gland disease, the sensitivity and specificity of 2-phase CT to correctly localize the quadrant were 55.4% and 85.9%, respectively. The sensitivity and specificity of correct lateralization were 78.8% and 67.8%, respectively. The sensitivity and specificity to identify multigland disease were 22.9% and 79.5%, respectively. While the 2-phase CT protocol in this study demonstrates lower accuracy compared with reports of other techniques, its lower radiation compared with 3- and 4-phase techniques may make it a feasible alternative for preoperative parathyroid localization. Further prospective studies are needed to identify patients for whom this technique is most suitable.