Adenoma Localization for Recurrent or Persistent Primary Hyperparathyroidism Using Dynamic Four-Dimensional CT and Venous Sampling

Diagnostic Accuracy of Four-Dimensional Computed Tomography in Preoperative Localization of Primary Hyperparathyroidism After Negative or Inconclusive Sestamibi: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the study is to assess the diagnostic accuracy of 4-dimensional computed tomography (4D-CT) scans for patients with primary hyperparathyroidism (pHPT) after negative or inconclusive Technetium-99m sestamibi single-photon emission computed tomography scan.

METHODS

A literature search of several databases was conducted from inception to August 2023. Eligible studies reported adult patients (>18 years old) who underwent 4D-CT after negative or inconclusive sestamibi results. The pooled proportions were analyzed using a random-effects model. This review was registered in PROSPERO (CRD42023446285).

RESULTS

From 208 initial studies screened, 10 met the eligibility criteria, with a total of 335 patients with a diagnosis of pHPT who underwent 4D-CT scans and subsequent surgical exploration. Nine of the studies reported a pooled sensitivity of localization of 71% (0.71; 95% confidence interval [CI]: 0.610, 0.811, I2  = 72%). The pooled specificity of localization across 5 studies was calculated at 47% (0.47; 95% CI: -0.111, 1.059, I2  = 99%). Seven of the included studies reported a pooled positive predictive value of 81% (0.81; 95% CI: 0.708, 0.917, I2  = 70%), and 6 of the studies reported a negative predictive value of 28% (0.28; 95% CI: -0.114, 0.683, I2  = 98%).

CONCLUSIONS

For pHPT patients with inconclusive sestamibi scans, 4D-CT demonstrates promising results with good diagnostic accuracy for the localization of pHPT. Additional studies evaluating larger groups of patients may provide further support for the use of 4D-CT in this population.

Comparison of 4D computed tomography and F-18 fluorocholine PET for localisation of parathyroid lesions in primary hyperparathyroidism: A systematic review and meta-analysis

Minimally invasive parathyroidectomy (MIP) is the standard of care for primary hyperparathyroidism (PHPT). Four dimensional computed tomography(4DCT) and F-18 Fluorocholine positron emission tomography/computed tomography (FCH PET/CT) localize adenomas accurately to perform MIP. We aimed to conduct a systematic review and metanalysis to evaluate the diagnostic performance of 4DCT and FCH PET/CT scan for quadrant wise localisation in PHPT patients and to do head-to-head comparison between these two modalities. DESIGN, PATIENTS AND MEASUREMENT : After searching through PubMed and EMBASE databases, 46 studies (using histology as a gold standard) of 4DCT and FCH PET/CT were included. RESULTS: Total number of patients included were 1651 and 952 for 4DCT scan (studies n = 26) and FCH PET/CT scan (studies n = 24) respectively. In per patient analysis, FCH PET/CT and 4DCT had pooled sensitivities of 92% (88-94) and 85% (73-92) respectively and in per lesion analysis, 90% (86-93) and 79% (71-84), respectively. In the subgroup with negative conventional imaging/persistent PHPT, FCH PET/CT had comparable sensitivity to 4DCT (84% [74-90] vs. 72% [46-88]). As per patient wise analysis, FCH PET/CT had better detection rates than 4DCT ([92.4 vs. 76.85], odds ratio -3.89 [1.6-9.36] p = .0024) in the subpopulation where both FCH PET/CT and 4DCT were reported. CONCLUSION: Both 4DCT and FCH PET/CT scan performed well in newly diagnosed patients, patients with persistent disease and in those with inconclusive conventional imaging results. FCH PET/CT scan had a higher pooled sensitivity than 4DCT in detecting patients with PHPT in head to head comparison.

Contemporary Multimodality Imaging of Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a disorder characterized by hypercalcemia and an elevated or inappropriately normal parathyroid hormone level. Classic features include bone pain, fractures, renal impairment, nephrolithiasis, and mental disturbance. However, most cases of PHPT are now asymptomatic at diagnosis or associated with nonspecific neurocognitive changes. The most frequent cause of PHPT is a solitary adenoma that secretes parathyroid hormone without the normal suppressive effect of serum calcium. A smaller number of cases can be attributed to multigland disease. Parathyroidectomy is curative and is considered for nearly all affected patients. Although PHPT is primarily a clinical and biochemical diagnosis, imaging is key to the localization of adenomas, which can lie in conventional locations adjacent to the thyroid gland or less commonly at ectopic sites in the neck and mediastinum. In addition, accurate localization facilitates the use of a minimally invasive or targeted surgical approach. Frequently used localization techniques include US, parathyroid scintigraphy, and four-dimensional CT. Second- and third-line modalities such as MRI, PET/CT, and selective venous sampling with or without parathyroid arteriography can increase confidence before surgery. These localization techniques, along with the associated technical aspects, relative advantages, and drawbacks, are described. Local expertise, patient factors, and surgeon preference are important considerations when determining the type and sequence of investigation. A multimodality approach is ultimately desirable, particularly in challenging scenarios such as multigland disease, localization of ectopic adenomas, and persistent or recurrent PHPT. Online supplemental material is available for this article. ^©RSNA, 2022.

18F-Fluorocholine PET and 4D-CT in Patients with Persistent and Recurrent Primary Hyperparathyroidism

Patients with primary hyperparathyroidism (pHPT) can develop persistent (P-pHPT) or recurrent (R-pHPT) disease after parathyroidectomy. Before recommending reoperation, recurrence must be accurately identified because of the high risk of complications. Our study evaluates ¹⁸F-fluorocholine (¹⁸F-FCH) PET/CT and 4D-CT integrated in PET/4D-CT in patients with P-pHPT/R-pHPT. Patients with P-pHPT/R-pHPT investigated by ¹⁸F-FCH PET/4D-CT between May 2018 and March 2021 were retrospectively included. Forty-two patients were included, 37 of whom underwent 4D-CT. The sensitivity and detection rate (DR%) were 95% and 88% for ¹⁸F-FCH PET/CT and 70% and 63% for 4D-CT, respectively. PET/CT and 4D-CT were concordant in 18/24 glands and concordant and positive in 15/24 (63%) glands. Discordant results were obtained for 6/24 glands. The surgical success rate was 65%. PET/CT showed significantly higher sensitivity than 4D-CT. Dynamic CT allowed the identification of no additional glands missed by PET/CT, and the combination of the 2 techniques did not improve the sensitivity or DR%. ¹⁸F-FCH PET/CT appears to be a valuable technique to accurately detect hyperfunctioning parathyroid tissue in patients with P-pHPT/R-pHPT and is better than 4D-CT. Except for cases with doubtful locations of PET targets that may require 4D-CT for surgical guidance, standard nonenhanced ¹⁸F-FCH PET/CT can be effectively recommended in patients with P-pHPT/R-pHPT before reoperation.

Assessment of 4DCT imaging findings of parathyroid adenomas in correlation with biochemical and histopathological findings

PURPOSE

To assess polar vessel presence and enhancement 4DCT imaging and their relation with biochemical and histopathological features.

METHODS

Patients with primary hyperparathyroidism and preoperative 4DCT imaging were screened retrospectively and those with histopathologically proven diagnosis of PA were included. Biochemical findings, densitometric measurements (HU_precontrast, HU_arterial, HU_venous, HU_wash-in, HU_wash-out, HU_retained) and CT_volume of PA on 4DCT, presence of a polar vessel (PV), and histopathological features were recorded. Correlations between serum PTH, calcium levels and densitometric measurements of PA on 4DCT were investigated. Differences between subgroups created according to PV presence were also evaluated.

RESULTS

Thirty-nine patients were enrolled (F/M = 32/7, median age = 57, interquartile range = 50-62 years). In all patients, serum PTH levels positively correlated with CT_volume (r = 0.398, p = 0.012) but negatively correlated with HU_arterial (r = - 0.366; p = 0.022), HU_venous (r = - 0.452; p = 0.004) and HU_retained (r = - 0.421; p = 0.008). In PV (-) PAs, PTH levels were positively correlated with CT_volume (r = 0.608, p ≤ 0.002) and negatively with HU_arterial (r = - 0.449, p ≤ 0.028), HU_venous (r = - 0.560, p = 0.004), HU_wash-in (r = - 0.460, p = 0.024), and HU_retained (r = - 0.539, p = 0.007). No correlation between PTH levels and densitometric measurements was found in PV (+) PAs. HU_wash-in and HU_wash-out were significantly higher in PV (+) PAs compared to PV (-) PAs (p = 0.021 and p = 0.033, respectively). Histopathologic features revealed no difference according to the presence of PV.

CONCLUSION

PTH levels might have an association with imaging findings of PAs, especially when categorized with respect to PV presence. PTH levels were negatively correlated with degree of enhancement in PV (-) PAs. Therefore, radiologists should be aware that in patients with high serum PTH levels and without a discernible PV, PA might be difficult to localize.

ACR Appropriateness Criteria® Parathyroid Adenoma

Hyperparathyroidism is defined as excessive parathyroid hormone production. The diagnosis is made through biochemical testing, in which imaging has no role. However, imaging is appropriate for preoperative parathyroid gland localization with the intent of surgical cure. Imaging is particularly useful in the setting of primary hyperparathyroidism whereby accurate localization of a single parathyroid adenoma can facilitate minimally invasive parathyroidectomy. Imaging can also be useful to localize ectopic or supernumerary parathyroid glands and detail anatomy, which may impact surgery. This document summarizes the literature and provides imaging recommendations for hyperparathyroidism including primary hyperparathyroidism, recurrent or persistent primary hyperparathyroidism after parathyroid surgery, secondary hyperparathyroidism, and tertiary hyperparathyroidism. Recommendations include ultrasound, CT neck without and with contrast, and nuclear medicine parathyroid scans. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

4DCT Scanning Technique for Primary Hyperparathyroidism: A Scoping Review

OBJECTIVE

4DCT for the detection of (an) enlarged parathyroid(s) is a commonly performed examination in the management of primary hyperparathyroidism. Protocols are often institution-specific; this review aims to summarize the different protocols and explore the reported sensitivity and specificity of different 4DCT protocols as well as the associated dose.

MATERIALS AND METHODS

A literature study was independently conducted by two radiologists from April 2020 until May 2020 using the Medical Literature Analysis and Retrieval System Online (MEDLINE) database. Articles were screened and assessed for eligibility. From eligible studies, data were extracted to summarize different parameters of the scanning protocol and observed diagnostic attributes.

RESULTS

A total of 51 articles were included and 56 scanning protocols were identified. Most protocols use three (n = 25) or four different phases (n = 23). Almost all authors include noncontrast enhanced imaging and an arterial phase. Arterial images are usually obtained 25-30 s after administration of contrast, and less agreement exists concerning the timing of the venous phase(s). A mean contrast bolus of 100 mL is administered at 3-4 mL/s. Bolus tracking is not often used (n = 3). A wide range of effective doses are reported, up to 28 mSv. A mean sensitivity of 81.5% and a mean specificity of 86% are reported.

CONCLUSION

Many different 4DCT scanning protocols for the detection of parathyroid adenomas exist in the literature. The number of phases does not appear to affect sensitivity or specificity. A triphasic approach, however, seems preferable, as three patterns of enhancement of parathyroid adenomas are described. Bolus tracking could help to reduce the variability of enhancement. Sensitivity and specificity also do not appear to be affected by other scan parameters like tube voltage or tube current. To keep the effective dose within limits, scanning at a lower fixed tube current seems preferable. Lowering tube voltage from 120 kV to 100 kV may yield similar image contrast but would also help lower the dose.

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.

Detection of parathyroid adenomas with multiphase 4DCT: towards a true four-dimensional technique

Background

Four-dimensional computed tomography (4DCT) is a commonly performed examination in the management of primary hyperparathyroidism, combining three-dimensional imaging with enhancement over time as the fourth dimension. We propose a novel technique consisting of 16 different contrast phases instead of three or four different phases. The main aim of this study was to ascertain whether this protocol allows the detection of parathyroid adenomas within dose limits. Our secondary aim was to examine the enhancement of parathyroid lesions over time.

Methods

For this prospective study, we included 15 patients with primary hyperparathyroidism and a positive ultrasound prior to surgery. We performed 4DCT with 16 different phases: an unenhanced phase followed by 11 consecutive arterial phases and 4 venous phases. Continuous axial scanning centered on the thyroid was performed over a fixed 8 cm or 16 cm coverage volume after the start of contrast administration.

Results

In all patients, an enlarged parathyroid lesion was demonstrated, and the mean lesion size was 13.6 mm. The mean peak arterial enhancement for parathyroid lesions was 384 Hounsfield units (HU) compared to 333 HU for the normal thyroid. No significant difference could be found. The time to peak (TTP) was significantly earlier for parathyroid adenomas than for normal thyroid tissue: 30.8 s versus 32.3 s (p value 0.008). The mean slope of increase (MSI) of the enhancement curve was significantly steeper than that of normal thyroid tissue: 29.8% versus 22.2% (p value 0.012). The mean dose length product was 890.7 mGy cm with a calculated effective dose of 6.7 mSv.

Conclusion

Our 4DCT protocol may allow better visualization of the pattern of enhancement of parathyroid lesions, as enhancement over time curves can be drawn. In this way, wash-in and wash-out of contrast in suspected lesions can be readily demonstrated. Motion artifacts are less problematic as multiple phases are available. Exposure to our proposed 4DCT technique is comparable to that for classic helical 4DCT. Careful selection of parameters (lowering kV and SNR) can help to further reduce the dose.

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

INTRODUCTION

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.

METHODS

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.

DISCUSSION

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.

CONCLUSIONS

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.

Parathyroid 4D CT: What the Surgeon Wants to Know

Parathyroid four-dimensional (4D) CT is an increasingly used and powerful tool for preoperative localization of abnormal parathyroid tissue in the setting of primary hyperparathyroidism. Accurate and precise localization of a single adenoma facilitates minimally invasive parathyroidectomy, and localization of multiglandular disease aids bilateral neck exploration. However, many radiologists find the interpretation of these examinations to be an intimidating challenge. The authors review parathyroid 4D CT findings of typical and atypical parathyroid lesions and provide illustrative examples. Relevant anatomy, embryology, and operative considerations with which the radiologist should be familiar to provide clinically useful image interpretations are also discussed. The most important 4D CT information to the surgeon includes the number, size, and specific location of candidate parathyroid lesions with respect to relevant surgical landmarks; the radiologist's opinion and confidence level regarding what each candidate lesion represents; and the presence or absence of ectopic or supernumerary parathyroid tissue, concurrent thyroid pathologic conditions, and arterial anomalies associated with a nonrecurrent laryngeal nerve. The authors provide the radiologist with an accessible and practical approach to performing and interpreting parathyroid 4D CT images, detail what the surgeon really wants to know from the radiologist and why, and provide an accompanying structured report outlining the key information to be addressed. By accurately reporting and concisely addressing the key information the surgeon desires from a parathyroid 4D CT examination, the radiologist substantially impacts patient care by enabling the surgeon to develop and execute the best possible operative plan for each patient. ^©RSNA, 2020.

Evaluation of an optimal cutoff of parathyroid venous sampling gradient for localizing primary hyperparathyroidism

INTRODUCTION

Parathyroid venous sampling (PVS) has been reported to be a useful adjunctive test in localizing lesions in elusive cases of primary hyperparathyroidism (PHPT). Conventional cutoff (twofold) is now widely being used, but optimal cutoff threshold for PVS gradient based on discriminatory performance remains unclear.

MATERIALS AND METHODS

Among a total of 197 consecutive patients (mean age 58.2 years, female 74.6%) with PHPT who underwent parathyroidectomy at a tertiary center between 2012 and 2018, we retrospectively analyzed 59 subjects who underwent PVS for persistent or recurrent disease after previous parathyroidectomy, or for equivocal or negative results from conventional imaging modalities including ultrasonography (US) and Tc^99m-Sestamibi SPECT-CT (MIBI). True parathyroid lesions were confirmed by combination of surgical, pathological findings, and intraoperative parathyroid hormone (PTH) changes. Optimal PVS cutoff were determined by receiver-operating characteristics (ROC) analysis with Youden and Liu method.

RESULTS

Compared to subjects who did not require PVS, PVS group tends to have lower PTH (119.8 pg/mL vs 133.7 pg/mL, p = 0.075). A total of 79 culprit parathyroid lesions (left 40; right 39) from 59 patients (left 24; right 26; bilateral 9) were confirmed by surgery. The optimal cutoff for PVS gradient was estimated as 1.5-fold gradient (1.5 ×) with sensitivity of 61.8% and specificity of 84%. When 1.5 × cutoff was applied, PVS improved the discrimination for true parathyroid lesions substantially based on area under ROC (0.892 to 0.942, p < 0.001) when added to US and MIBI.

CONCLUSION

Our findings suggest that PVS with cutoff threshold 1.5 × can provide useful complementary information for pre-operative localization in selected cases.

Benefit of diverse surgical approach on short-term outcomes of MEN1-related hyperparathyroidism

Surgical excision is the preferred treatment for multiple endocrine neoplasia type 1 (MEN1)-related primary hyperparathyroidism (PHPT), although controversy regarding the surgical strategy exists. We retrospectively investigated the short-term outcomes of PHPT by various surgical extents. Thirty-three patients who underwent parathyroidectomy due to MEN1-related PHPT at Yonsei Severance Hospital between 2005 and 2018 were included (age [mean ± SD], 43.4 ± 14.1 [range, 23–81] years). Total parathyroidectomy with auto-transplantation to the forearm (TPX) was the most common surgical method (17/33), followed by less-than-subtotal parathyroidectomy (LPX; 12/33) and subtotal parathyroidectomy (SPX; 4/33). There was no postoperative persistent hyperparathyroidism. Recurrence was high in the LPX group without significance (1 in TPX, 2 in SPX, and 3 in LPX, p = 0.076). Permanent and transient hypoparathyroidism were more common in TPX (n = 6/17, 35.3%, p = 0.031; n = 4/17, 23.5%, p = 0.154, respectively). Parathyroid venous sampling (PVS) was introduced in 2013 for preoperative localisation of hyperparathyroidism at our hospital; nine among 19 patients operated on after 2013 underwent pre-parathyroidectomy PVS, with various surgical extents, and no permanent hypoparathyroidism (p = 0.033) or post-LPX recurrence was observed. Although TPX with auto-transplantation is the standard surgery for MEN1-related PHPT, surgical extent individualisation is necessary, given the postoperative hypoparathyroidism rate of TPX and feasibility of PVS.

A case report of successful identification of ectopic parathyroid adenomas with a sequence of selective parathyroid venous sampling and 4D-computed tomography in a patient with recurrent hyperparathyroidism

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Ectopic parathyroid adenoma is a common cause of recurrent hyperparathyroidism.

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Identification of the ectopic parathyroid adenoma is the key to successful treatment.

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A sequence of PTH venous sampling followed by 4DCT found ectopic parathyroid adenomas when other investigations failed.

Introduction

Recurrent hyperparathyroidism is difficult to manage due to the difficulty in finding the missing adenoma. Herein we present a case of recurrent hyperparathyroidism from ectopic adenomas which basic investigations failed to locate but were finally localized by a 4DCT following selective venous sampling (SVS) of parathyroid hormone (PTH).

Presentation of case

A young female presented with recurrent hyperparathyroidism. She had severe primary hyperparathyroidism and temporary normocalcemia after first parathyroidectomy. Her hypercalcemia recurred and required second operation. However, the second operation was unsuccessful due to the pre-operation ultrasound, computed tomography (CT) neck, and sestamibi failed to identify the culprit parathyroid adenoma. After the second operation, positron emission tomography (PET), CT neck and sestamibi failed to identify the tumor but a sequence of SVS PTH and four-dimensional computed tomography (4DCT) successfully identified several ectopic adenomas.

Discussion

Ectopic parathyroid tissue is the most common cause of recurrent hyperparathyroidism but precisely locating these ectopic glands is often challenging. Despite modern modalities such as PET scans, the success rate is not impressive. SVS PTH is a good method to regionalize the ectopic source of PTH. With the more specified area, fine-tuning imaging with a 4DCT can identify the specific location of the ectopic parathyroid tissue.

Conclusion

A sequence of SVS PTH followed by 4DCT could identify the exact location of ectopic parathyroid adenomas in a patient when conventional non-invasive imaging studies failed.

Localization of Parathyroid Disease in Reoperative Patients with Primary Hyperparathyroidism

The localization of persistent or recurrent disease in reoperative patients with primary hyperparathyroidism presents challenges for radiologists and surgeons alike. In this article, we summarize the relevant imaging modalities, compare their accuracy in identifying reoperative disease, and outline their advantages and disadvantages. Accurate localization by preoperative imaging is a predictor of operative success, whereas negative or discordant preoperative imaging is a risk factor for operative failure. Ultrasound is a common first-line modality because it is inexpensive, accessible, and radiation-free. However, it is highly operator-dependent and less accurate in the reoperative setting than in the primary setting. Sestamibi scintigraphy is superior to ultrasound in localizing reoperative disease but requires radiation, prolonged imaging times, and reader experience for accurate interpretation. Like ultrasound, sestamibi scintigraphy is less accurate in the reoperative setting because reoperative patients can exhibit distorted anatomy, altered perfusion of remaining glands, and interference of radiotracer uptake. Meanwhile, four-dimensional computed tomography (4DCT) is superior to ultrasound and sestamibi scintigraphy in localizing reoperative disease but requires the use of radiation and intravenous contrast. Both 4DCT and magnetic resonance imaging (MRI) do not significantly differ in accuracy between unexplored and reoperative patients. However, MRI is more costly, inaccessible, and time-consuming than 4DCT and is inappropriate as a first-line modality. Hybrid imaging with positron emission tomography and computed tomography (PET/CT) may be a promising second-line modality in the reoperative setting, particularly when first-line modalities are discordant or inconclusive. Lastly, selective venous sampling should be reserved for challenging cases in which noninvasive modalities are negative or discordant. In the challenging population of reoperative patients with PHPT, a multimodality approach that utilizes the expertise of high-volume centers can accurately localize persistent or recurrent disease and enable curative parathyroidectomy.

4D-CT is Superior to Ultrasound and Sestamibi for Localizing Recurrent Parathyroid Disease

BACKGROUND

Recurrent primary hyperparathyroidism (PHPT) presents a diagnostic challenge in localizing a hyperfunctioning gland. Although several imaging modalities are available for preoperative localization, 4D-CT is increasingly utilized for its ability to locate both smaller and previously unlocalized lesions. Currently, there is a paucity of data evaluating the utility of 4D-CT in the reoperative setting compared with ultrasound (US) and sestamibi. We aimed to determine the sensitivity of 4D-CT in localizing parathyroid adenomas in recurrent or persistent PHPT.

METHODS

We performed a retrospective review of prospectively collected data from a tertiary-care hospital, and identified 58 patients who received preoperative 4D-CT with US and/or sestamibi between May 2008 and March 2016. Data regarding the size, shape, and number of parathyroid lesions were collected for each patient.

RESULTS

A total of 62 lesions were identified intraoperatively among the 58 patients (6 with multigland disease) included in this investigation. 4D-CT missed 13 lesions identified intraoperatively, compared with 32 and 22 lesions missed by US and sestamibi, respectively. Sensitivity for correct lateralization of culprit lesions was 77.4% for 4D-CT, 38.5% for US, and 46% for sestamibi. 4D-CT was superior in lateralizing adenomas (49/62) compared with US (20/52; p < 0.001) and sestamibi (18/47; p < 0.001). The overall cure rate (6-month postoperative calcium < 10.7 mg/dL) was 89.7%. All patients with lesions correctly lateralized by 4D-CT were cured at 6 months.

CONCLUSION

4D-CT localized parathyroid adenomas with higher sensitivity among patients with recurrent or persistent PHPT compared with sestamibi or US-based imaging.

Selective Parathyroid Hormone Venous Sampling in Patients with Persistent or Recurrent Primary Hyperparathyroidism and Negative, Equivocal or Discordant Noninvasive Imaging

BACKGROUND

In patients with persistent (P-PHPT) or recurrent (R-PHPT) primary hyperparathyroidism, preoperative localization is important. Selective parathyroid hormone venous sampling (sPVS) is an invasive technique that can be used to regionalize and/or lateralize the source of PHPT when noninvasive imaging studies are nonlocalizing. The aim of the present study was to assess the role of sPVS in the preoperative evaluation of patients with P-PHPT or R-PHPT and negative, equivocal, or discordant noninvasive imaging localization.

METHODS

After IRB-approval a retrospective review of all patients with P-PHPT or R-PHPT and nonlocalizing noninvasive imaging that underwent sPVS from 2000 to 2014 was performed. The location of the source of PHPT at sPVS was predicted by a parathyroid hormone (PTH) gradient and compared to the surgical, pathology, and biochemical follow-up data as the gold standard. Sensitivity and positive predictive value (PPV) were calculated.

RESULTS

Of 30 patients who underwent sPVS, 12 patients did not undergo surgical exploration due to negative or non-localizing PTH gradient (n = 8) or opted for medical management (n = 4). Of the 18 patients who underwent surgical exploration, 17 (94 %) had a positive PTH gradient and pathologic parathyroid tissue identified at surgery. Sensitivity and PPV of sPVS were 93 and 77 %, respectively, for all surgical cases, 86 and 60.0 % for cervical cases (n = 11), and 100 and 100 % for mediastinal cases (n = 7). Sixteen patients (89 %) were surgically cured.

CONCLUSIONS

In patients with P-PHPT or R-PHPT and nonlocalizing imaging studies, sPVS is a sensitive test for localizing the source of PHPT when a positive PTH gradient is present.

Preoperative Localization Studies in Primary Hyperparathyroidism

Primary hyperparathyroidism (pHPT) is the third most frequently seen endocrine disease and it is the most common cause of hypercalcemia seen in ambulatory patients. PHPT is most often (80%-85%) caused by a single parathyroid adenoma, followed by double adenoma (4%-5%), multiple gland hyperplasia (10%-15%), and parathyroid carcinoma (<1%). The diagnosis of pHPT is biochemically established and the only curative treatment is surgery. Since the cause of pHPT is typically single-gland disease, it is possible to determine the majority of pathological glands with preoperative localization methods and use the minimally invasive parathyroidectomy (MIP) approach. MIP has become the standard treatment for pHPT in selected patients. There are both noninvasive and invasive preoperative localization methods. Noninvasive methods currently used include ultrasonography (US), parathyroid scintigraphy, 4-dimensional computed tomography (CT), magnetic resonance imaging, and positron emission tomography-CT with 18F-fluoroquinolone and 11C-methionine. Preoperative invasive localization methods include parathyroid hormone (PTH) measurement with fine-needle aspiration biopsy, lateralization with PTH measurement via bilateral jugular vein sampling, selective venous sampling, and parathyroid arteriography. The aim of this study was to evaluate preoperative localization studies used in cases of pHPT.

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.

Correlation of Peripheral Vein Tumour Marker Levels, Internal Iliac Vein Tumour Marker Levels and Radical Prostatectomy Specimens in Patients with Prostate Cancer and Borderline High Prostate-Specific Antigen: A Pilot Study

PURPOSE

To correlate prostate-specific antigen (PSA), free to total PSA percentage (fPSA%) and prostatic acid phosphatase (PAP) levels from peripheral and pelvic venous samples with prostatectomy specimens in patients with prostate adenocarcinoma and borderline elevation of PSA.

MATERIALS AND METHODS

In this prospective institutional review board approved study, 7 patients with biopsy proven prostate cancer had a venous sampling procedure prior to prostatectomy (mean 3.2 days, range 1-7). Venous samples were taken from a peripheral vein (PVS), the right internal iliac vein, a deep right internal iliac vein branch, left internal iliac vein and a deep left internal iliac vein branch. Venous sampling results were compared to tumour volume, laterality, stage and grade in prostatectomy surgical specimens.

RESULTS

Mean PVS PSA was 4.29, range 2.3-6 ng/ml. PSA and PAP values in PVS did not differ significantly from internal iliac or deep internal iliac vein samples (p > 0.05). fPSA% was significantly higher in internal iliac (p = 0.004) and deep internal iliac (p = 0.003) vein samples compared to PVS. One of 7 patients had unilateral tumour only. This patient, with left-sided tumour, had a fPSA% of 6, 6, 6, 14 and 12 in his peripheral, right internal iliac, deep right internal iliac branch, left internal iliac and deep left internal iliac branch samples respectively. There were no adverse events.

CONCLUSION

fPSA%, unlike total PSA or PAP, is significantly higher in pelvic vein compared to peripheral vein samples when prostate cancer is present. Larger studies including patients with higher PSA values are warranted to further investigate this counterintuitive finding.

Imaging of the parathyroid glands in primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases worldwide. Surgery is the only potentially curable option for patients with this disorder, even though in asymptomatic patients 50 years of age or older without end organ complications, a conservative treatment may be a possible alternative. Bilateral neck exploration under general anaesthesia has been the standard for the definitive treatment. However, significant improvements in preoperative imaging, together with the implementation of rapid parathyroid hormone determination, have determined an increased implementation of focused, minimally invasive surgical approach. Surgeons prefer to have a localization study before an operation (both in the classical scenario and in the minimally invasive procedure). They are not satisfied by having been referred a patient with just a biochemical diagnosis of PHPT. Imaging studies must not be utilized to make the diagnosis of PHPT. They should be obtained to both assist in determining disease etiology and to guide operative procedures together with the nuclear medicine doctor and, most importantly, with the surgeon. On the contrary, apart from minimally invasive procedures in which localization procedures are an obligate choice, some surgeons believe that literature on parathyroidectomy over the past two decades reveals a bias towards localization. Therefore, surgical expertise is more important than the search for abnormal parathyroid glands.