ACR Appropriateness Criteria® Parathyroid Adenoma

Imaging Characteristics and Interpretation Strategy for Renal Hyperparathyroidism: A Retrospective 4-Dimensional Computed Tomography Study

OBJECTIVE

Parathyroidectomy treats uncontrolled renal hyperparathyroidism (RHPT), requiring identification of all glands. Three types of enhancement are proposed. Type A lesions have higher arterial phase attenuation than the thyroid, type B lesions lack higher arterial phase attenuation but have lower venous phase attenuation, and type C lesions have neither higher arterial phase attenuation nor lower venous phase attenuation than the thyroid. We aimed to outline the image features of problematic parathyroid glands in RHPT and propose a 4-dimensional computed tomography (4DCT) interpretation algorithm.

METHODS

This retrospective study involved data collection from patients with RHPT who underwent preoperative 4DCT for parathyroidectomy between January and November 2022. Pathologically confirmed parathyroid lesions were retrospectively identified on 4DCT according to the location and size described in the surgical notes. The attenuation of parathyroid lesions and the thyroid glands was assessed in 3 phases, and demographic data of the patients were collected.

RESULTS

Ninety-seven pathology-proven parathyroid glands from 27 patients were obtained, with 86 retrospectively detected on 4DCT. In the arterial phase, the attenuation of parathyroid lesions in RHPT did not exceed that of the thyroid gland (P < .001). In the venous phase, parathyroid lesions demonstrated lower attenuation than the thyroid gland (P < .001). A total of 81 parathyroid lesions (94.2%) exhibited type B patterns.

CONCLUSION

Unlike primary hyperparathyroidism, lesions in RHPT exhibited more type B enhancement, making them less readily identifiable in the arterial phase. Therefore, we propose a distinct imaging interpretation strategy to locate these problematic glands more efficiently.

Canadian Association of Radiologists Head and Neck Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Head and Neck Expert Panel consists of radiologists, a laryngologist and laryngeal surgeon, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 11 clinical/diagnostic scenarios, a systematic rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 17 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 26 recommendation statements across the 11 scenarios. This guideline presents the methods of development and the referral recommendations for sinus disease, tinnitus, thyroid and parathyroid disease, neck mass of unknown origin, acute sialadenitis, chronic salivary conditions, and temporomandibular joint dysfunction.

Expression of the Calcium-Sensing Receptor on Normal and Abnormal Parathyroid and Thyroid Tissue

INTRODUCTION

Current imaging techniques have several limitations in detecting parathyroid glands. We have investigated the calcium-sensing receptor (CaSR) as a potential target for specifically labeling parathyroid glands for radiologic detection. For accurate imaging it is vital that a large differential expression exists between the target tissue and adjacent structures. We sought to investigate the relative abundance of the CaSR in normal and abnormal parathyroid tissue, as well as normal and abnormal thyroid.

METHODS

Existing clinical specimens were selected that represented a wide variety of pathologically and clinically confirmed malignant and benign thyroid and parathyroid specimens. Sections were stained for the CaSR using immunohistochemistry and scored for intensity and abundance of expression. (H score = intensity scored from 0 to 3 multiplied by the % of cells at each intensity. Range 0-300).

RESULTS

All parathyroid specimens expressed the CaSR to a high degree. Normal parathyroid had the highest H score (271, s.d. 25.4). Abnormal parathyroid specimens were slightly lower but still much higher than normal thyroid (H score 38.3, s.d. 23.3). Medullary thyroid cancer also expressed the CaSR significantly higher than normal thyroid (H score 182, s.d. 69.1, P < 0.001) but below parathyroid levels. Hürthle cell carcinoma expressed the CaSR to a lesser degree but higher than normal thyroid (H score 101, s.d. 46.4, P = 0.0037).

CONCLUSIONS

The CaSR is differentially expressed on parathyroid tissue making it a feasible target for parathyroid imaging. False positives might be anticipated with medullary and Hürthle cell cancers.

Can we skip technetium-99 m sestamibi scintigraphy in pediatric primary hyperparathyroidism patients with positive neck ultrasound results?

BACKGROUND

Parathyroidectomy is the only curative treatment for primary hyperparathyroidism (PHPT). Ultrasound (US) and technetium-99 m sestamibi (99mTc-MIBI) scintigraphy are recommended as the first-line localization imaging modalities for PHPT in adults, but the value of preoperative imaging in pediatric patients has not been reported.

OBJECTIVE

To evaluate the added value of 99mTc-MIBI scintigraphy in pediatric PHPT patients with positive ultrasound results.

MATERIALS AND METHODS

Pediatric patients (≤18 years old) who were diagnosed with PHPT and underwent surgical treatment in Peking Union Medical College Hospital between January 2003 and January 2021 were included in this study. Demographic and clinical characteristics, preoperative localization US, 99mTc-MIBI scintigraphy and pathology results were collected. Preoperative localization results were evaluated by comparison with surgical and pathological findings.

RESULTS

There were 32 pediatric PHPT patients with median age of 14.7 ± 2.5 years who all proved to have single-gland disease without ectopic lesions. The median lesion size was 2.85 cm (range 1.0-5.8 cm). All patients underwent US and 99mTc-MIBI scintigraphy. Neck US demonstrated 100% sensitivity. Of 32 patients with a positive US, 99mTc-MIBI scintigraphy was concordant in 30 (93.8%). In 2 patients (6.3%), US reported suspected multigland disease, which was correctly diagnosed by 99mTc-MIBI scintigraphy as single lesions.

CONCLUSION

In pediatric PHPT patients, US achieved high sensitivity for preoperative localization. 99mTc-MIBI scintigraphy for pediatric patients with positive US results would not increase the sensitivity. Implementation of 99mTc-MIBI scintigraphy could increase the specificity in pediatric patients with multigland disease suspected by US.

Opportunistic CT Assessment of Parathyroid Glands: Utility of Radiologist-Recommended Biochemical Evaluation for Diagnosing Primary Hyperparathyroidism

BACKGROUND. Existing gaps in primary hyperparathyroidism (PHPT) diagnosis and treatment have prompted calls for systemic change in the approach to this disease. One proposed change is opportunistic assessment for enlarged parathyroid glands on routine CT examinations, to target biochemical testing to individuals most likely to have un-diagnosed PHPT. OBJECTIVE. The purpose of our study was to assess the utility of a radiologist recommendation for biochemical testing in patients with a suspected enlarged parathyroid gland on routine CT for identifying previously undiagnosed PHPT. METHODS. This retrospective study included patients without known or suspected PHPT who underwent routine CT (i.e., performed for reasons other than known or suspected parathyroid disease) between August 2019 and September 2021 in which the clinical CT report included a radiologist recommendation for biochemical testing to evaluate for possible PHPT because of a suspected enlarged parathyroid gland. Neuroradiologists at the study institution included this recommendation on the basis of individual judgment without formal criteria. The EHR was reviewed to identify patients who underwent subsequent laboratory evaluation for PHPT. An endocrine surgeon used available laboratory results and clinical data to classify patients as having PHPT, secondary hyper-parathyroidism, or no parathyroid disorder independent of the CT findings. RESULTS. The sample comprised 39 patients (median age, 68 years; 20 women, 19 men) who received the radiologist recommendation for biochemical evaluation. Of these patients, 13 (33.3%) received the recommended biochemical evaluation. Of the 13 tested patients, three (23.1%) were classified as having PHPT, four (30.8%) as having secondary hyperparathyroidism, and six (46.2%) as having no parathyroid disorder. Thus, the number of patients needing to receive a radiologist recommendation for biochemical testing per correct PHPT diagnosis was 13.0, and the number of patients needing to undergo laboratory testing per correct PHPT diagnosis was 4.3. One of the three patients classified as having PHPT underwent surgical resection of the lesion identified by CT, which was shown on histopathologic evaluation to represent hypercellular parathyroid tissue. CONCLUSION. Radiologist recommendations for biochemical testing in patients with suspected enlarged parathyroid glands on routine CT helped to identify individuals with undiagnosed PHPT. CLINICAL IMPACT. Opportunistic assessment for enlarged parathyroid glands on routine CT may facilitate PHPT diagnosis.

C11 choline PET/CT succeeds when conventional imaging for primary hyperparathyroidism fails

BACKGROUND

Focused parathyroidectomy in primary hyperparathyroidism is possible with accurate preoperative localization. A growing body of data exists regarding the role of radio-labeled C¹¹ choline positron emission tomography/computed tomography. In cases of nonlocalized disease, it may be a useful adjunct to ultrasound, (123)I/(99)Tc-sestamibi (I-123 sestamibi), or 4-dimensional computed tomography imaging.

METHODS

Patients who received a neck and chest limited coverage C¹¹ choline positron emission tomography/computed tomography for evaluation of primary hyperparathyroidism from 2017 to 2021 at a single institution were retrospectively reviewed. We assessed the sensitivity, positive predictive value, and false negative rate. We also compared these rates to the standard modalities of ultrasound, I-123 sestamibi, 4-dimensional computed tomography, and examined concordance rates.

RESULTS

We identified 43 patients, of whom 33 had a positive C¹¹ choline positron emission tomography/computed tomography finding. This cohort of patients had failed to localize on multiple standard imaging modalities. Twenty-five patients proceeded to surgery, 72% of whom were reoperative cases. Twenty (80%) achieved an intraoperative cure. Analysis showed that C¹¹ choline positron emission tomography/computed tomography achieved a sensitivity of 64% (95% confidence interval 47%-82%) and positive predictive value of 72% (95% confidence interval 54%-90%). There were 5/25 (20%) false positive positron emission tomography C¹¹ choline results found to be lymph nodes, normal parathyroid, and 1 recurrent laryngeal nerve neuroma.

CONCLUSION

C¹¹ choline positron emission tomography/computed tomography is a useful adjunct for parathyroid localization in a complex population of patients who have failed standard localization techniques including ultrasound, I-123 sestamibi, or 4-dimensional computed tomography and/or prior operations. Although routine inclusion of C¹¹ choline positron emission tomography/computed tomography imaging may not be necessary, it may aid in preoperative localization in the reoperative setting.

Parathyroid adenoma presenting as chronic pancreatitis: A case report and literature review

BACKGROUND

Most patients with parathyroid adenomas are asymptomatic and rarely present with chronic pancreatitis (CP). Several studies have reported a positive association between primary hyperparathyroidism (PHPT) and pancreatitis. Parathyroidectomy is the definitive treatment for PHPT. IV bisphosphonates can be considered the drug of choice for bridge to surgery.

METHODS

We reported a 57-year-old female patient was admitted to the emergency room with left upper quadrant abdominal pain and a diagnosis of recurrent pancreatitis. Magnetic Resonance Cholangiopancreatography confirmed the diagnosis of CP. The patient had no common etiology of pancreatitis. Persistent hypercalcemia was noted despite administering intravenous fluids, and Calcitonin. Intravenous Pamidronate, a Bisphosphonate derivative, was also administered. Although calcium levels initially decreased, they were later found to rebound to previous levels.

RESULTS

A diagnosis of parathyroid adenoma and PHPT was made based on the elevated parathyroid hormone levels and cervical ultrasonography indicated right inferior parathyroid adenoma. Technetium-99m methoxy-isobutyl-isonitrile scintigraphy revealed a focal hot spot of tracer accumulation at the right lower thyroid bed. The patient underwent right lower parathyroidectomy smoothly and successfully. After right lower parathyroidectomy, she had normal serum calcium levels (9.2 mg/dL) and parathyroid hormone (16.1 pg/mL). There was no recurrent abdominal pain after the operation.

CONCLUSION

CP is a rare manifestation of parathyroid adenoma. When patients with a history of recurrent pancreatitis, without common causes of pancreatitis, present persistent elevated serum calcium levels, PHPT could be suspected.

An Ectopic Parathyroid Adenoma Mimicking Submandibular Gland on 99mTc-MIBI Parathyroid Scintigraphy

ABSTRACT

A 67-year-old woman complained of continuous low back pain for 4 months. She was referred for a 99mTc-MIBI parathyroid scintigraphy with neck SPECT/CT imaging. The planar images showed no abnormal uptake. However, on the SPECT/CT scan, a soft tissue nodule with high uptake was noted adjacent to the left submandibular gland, mimicking normal submandibular gland uptake. Pathological examination from surgical specimen showed that it was an ectopic parathyroid adenoma.

Lessons learnt from the global iodinated contrast media shortage in head and neck imaging

A recent shortage in the global supply of iodinated contrast media (ICM) has required health service providers to review their contrast administration policies and implement strategies to conserve inventory. This article will review the current best practices in head and neck imaging for a variety of common presentations and provide examples where alternative imaging can be considered due to the recent ICM shortage. Ultrasound and MRI techniques can feature heavily in many diagnostic processes in head and neck pathology, and a variety of common presentations can be appropriately investigated through clinical evaluation or naso-endoscopy. In many instances, for the routine assessment of non-acute adult and paediatric head and neck presentations, the use of contrast-enhanced CT can be safely minimised to conserve ICM if required.

Primary hyperparathyroidism, a machine learning approach to identify multiglandular disease in patients with a single adenoma found at preoperative Sestamibi-SPECT/CT

OBJECTIVE

Successful preoperative image localisation of all parathyroid adenomas (PTA) in patients with primary hyperparathyroidism (pHPT) and multiglandular disease (MGD) remains challenging. We investigate whether a machine learning classifier (MLC) could predict the presence of overlooked PTA at preoperative localisation with 99mTc-Sestamibi-SPECT/CT in MGD patients.

DESIGN

This study is a retrospective study from a single tertiary referral hospital initially including 349 patients with biochemically confirmed pHPT and cured after surgical parathyroidectomy.

METHODS

A classification ensemble of decision trees with Bayesian hyperparameter optimisation and five-fold cross-validation was trained with six predictor variables: the preoperative plasma concentrations of parathyroid hormone, total calcium and thyroid-stimulating hormone, the serum concentration of ionised calcium, the 24-h urine calcium and the histopathological weight of the localised PTA at imaging. Two response classes were defined: patients with single-gland disease (SGD) correctly localised at imaging and MGD patients in whom only one PTA was localised on imaging. The data set was split into 70% for training and 30% for testing. The MLC was also tested on a subset of the original data based on CT image-derived PTA weights.

RESULTS

The MLC achieved an overall accuracy at validation of 90% with an area under the cross-validation receiver operating characteristic curve of 0.9. On test data, the MLC reached a 72% true-positive prediction rate for MGD patients and a misclassification rate of 6% for SGD patients. Similar results were obtained in the testing set with image-derived PTA weight.

CONCLUSIONS

Artificial intelligence can aid in identifying patients with MGD for whom 99mTc-Sestamibi-SPECT/CT failed to visualise all PTAs.

Opportunistic Parathyroid Gland Assessment on Routine CT Could Decrease Morbidity from Undiagnosed Primary Hyperparathyroidism

RATIONALE AND OBJECTIVES

Gaps in primary hyperparathyroidism diagnosis are well-documented. End-organ damage correlates with disease duration and often occurs before diagnosis. We hypothesize that opportunistic parathyroid gland assessment on routine CT could decrease existing diagnosis gaps. Our purpose is to assess for enlarged parathyroid glands on contrast-enhanced CT acquired prior to biochemical screening and subsequent development of related morbidity.

MATERIALS AND METHODS

This retrospective study included consecutive patients with primary hyperparathyroidism undergoing parathyroidectomy with contrast-enhanced CT including the lower neck and upper chest acquired prior to biochemical screening. One neuroradiologist retrospectively evaluated all CTs for enlarged (estimated weight greater than 60 mg) parathyroid glands. Gold standard operative and pathology reports were correlated with CT findings, and medical records were reviewed for development of primary hyperparathyroidism-related comorbidities.

RESULTS

The sample comprised 38 patients (30 women, 8 men, median age 60 years) with 70 CTs of interest. The neuroradiologist identified 32 putative enlarged parathyroid glands (median estimated weight 307 mg) in 29 (76%) patients on CTs predating biochemical screening by a median of 30 months. Putative enlarged parathyroid glands on CT corresponded to pathologically proven parathyroid lesions in 26 (90%) patients. Of 26 patients with retrospectively identified pathologically proven parathyroid lesions, 12 (46%) developed at least 1 renal, bone, or neurocognitive comorbidity between CT and subsequent biochemical screening.

CONCLUSION

Enlarged parathyroid glands are frequently visible on routine CTs acquired years prior to primary hyperparathyroidism diagnosis. Biochemical screening based on enlarged glands could potentially prevent associated morbidity in almost half of such patients.