A comparative study of pre-operative imaging methods in patients with primary hyperparathyroidism: ultrasonography, 99mTc sestamibi, single photon emission computed tomography, and magnetic resonance imaging

[Mediastinal Tumors]

If mediastinal tumours cause symptoms these are related to their anatomical localization or a paraneoplastic syndrome. The differential diagnosis is based on the clinical situation with finding the lesion, and, furthermore, taking into account the age and sex of the patient, and the mediastinal compartment where the lesion is located. Cross-sectional radiographic diagnostic is essential for defining the therapeutic strategy. The anterior mediastinum is dominated by thymic tumours, mediastinal lymphomas, germ cell tumours and ectopic mediastinal poiters. The middle mediastinal compartment is the most frequent place of mediastinal cystic tumours, whereas the posterior mediastinum is the domain of neurogenic tumours. For selected cases a tissue biopsy is required. Surgery is the mainstay for most mediastinal tumours. Median sternotomy is the most frequent conventional surgical technique while minimally invasive surgery with thoracoscopic and above all robot assisted operation techniques are increasingly frequent. Combined chemotherapy and modern radiotherapy are essential components of the comprehensive treatment for mediastinal tumours.

A retrospective analysis of the diagnostic performance of 11C-choline PET/CT for detection of hyperfunctioning parathyroid glands after prior negative or discordant imaging in primary hyperparathyroidism

Background

Identifying the correct location of a parathyroid adenoma in patients with primary hyperparathyroidism (pHPT) is crucial as it can guide surgical treatment. This study aimed to determine the diagnostic performance of ¹¹C-choline PET/CT in patients with pHPT as a next in-line scan after primary negative or discordant first-line imaging.

Methods

This was a retrospective single-center cohort study. All patients with pHPT that were scanned utilizing ¹¹C-choline PET/CT, after prior negative or discordant imaging, between 2015 and 2019 and who subsequently underwent parathyroid surgery were included. The results of the ¹¹C-choline PET/CT were evaluated lesion-based, with surgical exploration and histopathological examination as the gold standard.

Results

In total, 36 patients were included of which three patients were known to have Multiple Endocrine Neoplasia (MEN) syndrome. In these 36 patients, 40 lesions were identified on ¹¹C-choline PET/CT and 37 parathyroid lesions were surgically removed. In 34/36 (94%) patients a focused parathyroidectomy was performed, in one patient a cervical exploration due to an ectopically identified adenoma, and in one patient a bilateral exploration was performed because of a double adenoma. Overall, per-lesion sensitivity of ¹¹C-choline PET/CT was 97%, the positive predictive value was 95% and the accuracy was 94% for all parathyroid lesions.

Conclusions

In patients with pHPT and prior negative or discordant first-line imaging results, pathological parathyroid glands can be localized by ¹¹C-choline PET/CT with high sensitivity and accuracy.

Upfront F18-choline PET/CT versus Tc99m-sestaMIBI SPECT/CT guided surgery in primary hyperparathyroidism: the randomized phase III diagnostic trial APACH2

BACKGROUND

The common endocrine disorder primary hyperparathyroidism (PHPT) can be cured by surgery. Preoperative localization of parathyroid adenoma (PTA) by imaging is a prerequisite for outpatient minimally invasive parathyroidectomy (MIP). Compared to inpatient bilateral cervical exploration (BCE) which is performed if imaging is inconclusive, MIP is superior in terms of cure and complication rates and less costly. The imaging procedure F18-choline (FCH) PET/CT outperforms Tc99m-sestaMIBI (MIBI) SPECT/CT for PTA localization, but it is much costlier. The aim of this study is to identify the most efficient first-line imaging modality for optimal patient care in PHPT without added cost to society.

METHODS

We will conduct a multicenter open diagnostic intervention randomized phase III trial comparing two diagnostic strategies in patients with PHPT: upfront FCH PET/CT versus MIBI SPECT/CT. The primary endpoint is the proportion of patients in whom the first-line imaging method results in successful MIP and cure. Follow-up including biological tests will be performed 1 and 6 months after surgery. The main secondary endpoint is the social cost of both strategies. Other secondary endpoints are as follows: FCH PET/CT and MIBI SPECT/CT diagnostic performance, performance of surgical procedure and complication rate, FCH PET/CT inter- and intra-observer variability and optimization of FCH PET/CT procedure. Fifty-eight patients will be enrolled and randomized 1:1.

DISCUSSION

FCH PET/CT is a highly efficient but expensive imaging test for preoperative PTA localization and costs three to four times more than MIBI SPECT/CT. Whether FCH PET/CT improves patient outcomes compared to the reference standard MIBI SPECT/CT is unknown. To justify its added cost, FCH PET/CT-guided parathyroid surgery should lead to improved patient management, resulting in higher cure rates and fewer BCEs and surgical complications. In the previous phase II APACH1 study, we showed that second-line FCH PET/CT led to a cure in 88% of patients with negative or inconclusive MIBI SPECT/CT. BCE could be avoided in 75% of patients and surgical complication rates were low. We therefore hypothesize that upfront FCH PET/CT would improve patient care in PHPT and that the reduction in clinical costs would offset the increase in imaging costs.

TRIAL REGISTRATION

NCT04040946 , registered August 1, 2019.  Protocol version Version 2.1 dated from 2020/04/23.

Overt metabolic bone failure as the initial manifestation of neglected primary hyperparathyroidism: An unusual presentation and review of current practice guidelines

Varied symptomatology exists in hyperparathyroidism. The current approaches and evaluation of altered calcium homeostasis have led to the practice of early identification and subsequent management of the adenomas. Hence, bony manifestations (deformities, lesions, and fractures) termed to be end stage of bone metabolism failure, have rarely been encountered in the last two decades. We report this infrequent presentation in a 47-year-old female, who visited the emergency department following a trivial fall. Her background history recorded left superior parathyroidectomy three months prior to fall. The clinical and radiological evaluations were suggestive of insufficiency fractures of right proximal humerus and right shaft of femur, multiple lytic lesions and other bony manifestations pathognomonic of hyperparathyroidism. Metabolic profile revealed a primary cause despite prior adenectomy, and targeted scintigraphy demonstrated a hyper-functioning right inferior parathyroid gland. The high resolution ultrasound used before the prior surgery failed to localise additional hyper-functioning glands. Post-parathyroidectomy, the hungry bone disease was adequately managed. The femur fracture required surgical stabilization. In conclusion, bony manifestations of hyperparathyroidism can be disabling and difficult to treat. Although a rare clinical presentation, the severity of bony manifestations arise from a preventable cause and that the initial evaluation of hyperparathyroidism should also include parathyroid scintigraphy, and not limited to screening of the neck with ultrasonography, for its combined additive information and improved diagnostic value.

Optimization of parathyroid 11C-choline PET protocol for localization of parathyroid adenomas in patients with primary hyperparathyroidism

PURPOSE

To evaluate the optimal tracer uptake time, the minimal amount of radioactivity and the inter-observer agreement for ¹¹C-choline positron emission tomography/computed tomography (PET/CT) in patients with primary hyperparathyroidism (pHPT).

METHODS

Twenty-one patients with biochemically proven pHPT were retrospectively studied after injection of 6.3 ± 1.2 MBq/kg ¹¹C-choline. PET data of the first nine patients, scanned for up to 60 min, were reconstructed in 10-min frames from 10- to 60-min postinjection (p.i.), mimicking varying ¹¹C-choline uptake times. Parathyroid adenoma to background contrast ratios were calculated and compared, using standardized uptake values (SUVs). Data was reconstructed with varying scan durations (1, 2.5, 5, and 10 min) at 20-30-min p.i. (established optimal uptake time), mimicking less administered radioactivity. To establish the minimal required radioactivity, the SUVs in the shorter scan durations (1, 2.5, and 5 min) were compared to the 10-min scan duration to determine whether increased variability and/or statistical differences were observed. Four observers analyzed the ¹¹C-choline PET/CT in four randomized rounds for all patients.

RESULTS

SUVpeak of the adenoma decreased from 30 to 40 p.i. onwards. All adenoma/background contrast ratios did not differ from 20- to 30-min p.i. onwards. The SUVs of adenoma in the scan duration of 1, 2.5, and 5 min all differed significantly from the same SUV in the 10-min scan duration (all p = 0.012). However, the difference in absolute SUV adenoma values was well below 10% and therefore not considered clinically significant. The inter-observer analysis showed that the Fleiss' kappa of the 1-min scan were classified as "moderate," while these values were classified as "good" in the 2.5-, 5-, and 10-min scan duration. Observers scored lower certainty scores in the 1- and 2.5-min scans compared to the 5- and 10-min scan durations.

CONCLUSION

The optimal time to start PET/CT scanning in patients with pHPT is 20 min after mean injection of 6.3 MBq/kg ¹¹C-choline, with a recommended scan duration of at least 5 min. Alternatively, the radioactivity dose can be lowered by 50% while keeping a 10-min scan duration without losing the accuracy of ¹¹C-choline PET/CT interpretation.

Importance of Parathyroid Hormone Needle Aspiration Washout in Adenoma Localization in Primary Hyperparathyroidism

Background

Primary hyperparathyroidism is an endocrine disease characterized by excessive secretion of parathyroid hormone and hypercalcemia. Although scintigraphy is commonly used for pre-operative localization, it does not always localize the parathyroid lesion. In such patients, ultrasonography can visualize the suspected lesion and needle washout sample for parathyroid hormone titer can be used to confirm parathyroid tissue. The aim of this study was to investigate the accuracy of the parathyroid hormone needle aspiration washout method in detecting the localization of parathyroid adenoma.

Material/Methods

Patients with primary hyperparathyroidism who underwent surgery between 2010 and 2017 at the Dicle University Medical Faculty Hospital were retrospectively evaluated using medical records. Patients undergoing parathyroid hormone needle aspiration washout were performed in the suspected lesion were included in the study. Accompanied by ultrasonography, the suspected area was penetrated with needle, and negative aspiration was performed. Pre-operative scintigraphic data of patients were evaluated. Patients with positive scintigraphy, negative scintigraphy or patients who did not undergo scintigraphy were included in our study. Demographic data were presented as continuous data means ± standard deviation. Categorical variables were presented as frequency and percentage.

Results

Forty-nine patients (female/male, 40/9) who underwent parathyroid hormone needle aspiration washout were included in the study. Parathyroid hormone washout result was positive in 47 patients (47/49) and negative in 2 patients (2/49), sensitivity/positive predictive value (PPV) 95.91%. Twenty-six patients who had negative/suspicious scintigraphic results were diagnosed using the parathyroid hormone needle aspiration washout method (24/26, 92.3% accuracy). Parathyroid hormone needle aspiration washout without scintigraphy was performed in 13 patients (13/13, 100% accuracy).

Conclusions

Parathyroid adenoma localization can be easily done using parathyroid hormone needle aspiration washout in centers experienced in adenoma localization in primary hyperparathyroidism cases in which scintigraphic results are negative or scintigraphy cannot be performed. We believe that primary parathyroid hormone needle aspiration washout can be a new localization method for adenoma localization.

3-phase dual-energy CT scan as a feasible salvage imaging modality for the identification of non-localizing parathyroid adenomas: a prospective study

Objectives

Accurate pre-operative imaging of parathyroid adenomas (PAs) is essential for successful minimally invasive surgery; however, rates of non-localizing PAs can be as high as 18 %. Multiphasic dual-energy CT (DECT) has the potential to increase accuracy of PA detection by enabling creation of paired material maps and spectral tissue characterization. This study prospectively evaluated the utility of 3-phase DECT for PA identification in patients with failed localizatio n via standard imaging.

Methods

Patients with primary hyperparathyroidism and non-localizing PAs underwent a 3 phase post-contrast DECT scan acquired at 25, 55, and 85 s. The scans were prospectively evaluated by two head and neck radiologists. Pre-operative localization was compared to intraoperative localization and final histopathology. A post-hoc DECT spectral density characterization was performed on pathologically-proven PAs.

Results

Out of 29 patients with primary hyperparathyroidism and non-localized PAs, DECT identified candidates in 26. Of the 23 patients who underwent parathyroidectomy, DECT provided precise anatomic localization in 20 patients (PPV = 87.0 %), one with multi-gland disease. The virtual unenhanced images were not found to be useful for diagnosis but successful diagnosis was made without an unenhanced phase regardless. Spectral analysis demonstrated a distinct spectral Hounsfield attenuation curve for PAs compared to lymph nodes on arterial phase images.

Conclusion

3-phase DECT without an unenhanced phase is a feasible salvage imaging modality for previously non-localizing parathyroid adenomas. Optimal interpretation is achieved based on a combination of perfusion characteristics and other morphologic features. Advanced spectral DECT analysis has the potential for further increasing accuracy of PA identification in the future.