Parathyroid 4D-CT in Primary Hyperparathyroidism: Exploration of Size Measurements for Identifying Multigland Disease and Guiding Biochemically Successful Parathyroidectomy

Four-dimensional computed tomography as first-line imaging in primary hyperparathyroidism, a retrospective comparison to conventional imaging in a predominantly single adenoma population

BACKGROUND

To determine the use of four-dimensional CT as first-line imaging compared to the traditional combination of ultrasound and [99mTc]Tc-Sestamibi SPECT.

MATERIALS AND METHODS

Retrospective review of preoperative imaging in patients with primary hyperparathyroidism, who underwent parathyroidectomy between 2012 and 2021. In one group, the combination ultrasound and [99mTc]Tc-Sestamibi SPECT was used as first-line imaging (n = 54), in the other group four-dimensional CT was the first-line imaging modality (n = 51). Sensitivity and positive predictive value were calculated on patient, lateralisation and localisation level. The need for additional imaging was also assessed for both groups.

RESULTS

Four-dimensional CT had a significantly higher sensitivity compared to the combination of ultrasound/[99mTc]Tc-Sestamibi SPECT on patient and localisation level (70.6% vs. 51.9%, p = 0.049 and 60.8% vs. 35.2%, p = 0.009 respectively). Sensitivity for lateralisation also appeared higher, but did not reach significance (62.7% vs. 44.4%, p = 0.060). Positive predictive value was not significantly higher for four-dimensional CT compared to ultrasound and [99mTc]Tc-Sestamibi SPECT (88.9% vs. 85.7% for lateralisation and 86.1% vs. 67.9% for localisation respectively). Additional imaging was required in 14 patients with four-dimensional CT as first-line imaging (27.4%) consisting of 2 ultrasound/[99mTc]Tc-Sestamibi SPECT and 13 [18F]fluorocholine PET/CT, compared to 24 patients with ultrasound/[99mTc]Tc-Sestamibi SPECT as first-line imaging (44.4%), requiring 22 four-dimensional CT and 9 [18F]fluorocholine PET/CT.

CONCLUSIONS

Four-dimensional CT as the sole first-line parathyroid imaging modality had higher sensitivity than the combination of ultrasound and [99mTc]Tc-Sestamibi SPECT, therefore requiring fewer additional procedures. Although the most costly, [18F]fluorocholine PET/CT was the most effective technique to localise parathyroid adenoma in case all other imaging was negative.

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.

Preoperative imaging in primary hyperparathyroidism patients using 4DCT subtraction maps, a report of three cases

Four-dimensional computed tomography (4DCT) is one of the preoperative imaging modalities that can be used to localize a parathyroid adenoma in primary hyperparathyroidism patients however, sensitivity differs in literature and could be improved especially for multiglandular hyperplasia or double adenomas. The most robust feature on the 4DCT for the differentiation between parathyroid adenoma and thyroid gland tissue is arterial enhancement. To make this better visible, we have developed a subtraction map that shows arterial enhancement as a color scale to increase sensitivity for 4DCT. In this report of 3 cases, we present the usefulness of this subtraction map in a 54-year-old male, a 57-year-old female and a 51-year-old male. Subtraction maps may increase sensitivity for 4DCT, especially for multiglandular hyperplasia or double adenomas.

Predicting multigland disease in primary hyperparathyroidism using ultrasound and clinical features

Background

The identification of multigland disease (MGD) in primary hyperparathyroidism (PHPT) patients is essential for minimally invasive surgical decision-making.

Objective

To develop a nomogram based on ultrasound (US) findings and clinical factors to predict MGD in PHPT patients.

Materials and methods

Patients with PHPT who had surgery between March 2021 and January 2022 were consecutively enrolled to this study. Biochemical and clinicopathological data were recorded. US images were analyzed to extract US features for prediction. Logistic regression analyses were used to identify MGD risk factors. A nomogram was constructed based on these factors and its performance evaluated by area under the receiver operating characteristic curve (AUC), calibration curve, Hosmer-Lemeshow tests, and decision curve analysis (DCA).

Results

A total of 102 PHPT patients were included; 82 (80.4%) had single-gland disease (SGD) and 20 (19.6%) had MGD. Using multivariate analyses, MGD was positively correlated with age (odds ratio (OR) = 1.033, 95% confidence interval (CI): 0.190-4.047), PTH levels (OR = 1.001, 95% CI: 1.000-1.002), multiple endocrine neoplasia type 1 (MEN1) (OR = 29.730, 95% CI: 3.089-836.785), US size (OR = 1.198, 95% CI: 0.647-2.088), and US texture (cystic-solid) (OR = 5.357, 95% CI: 0.499-62.912). MGD was negatively correlated with gender (OR = 0.985, 95% CI: 0.190-4.047), calcium levels (OR = 0.453, 95% CI: 0.070-2.448), and symptoms (yes) (OR = 0.935, 95% CI: 0.257-13.365). The nomogram showed good discrimination with an AUC = 0.77 (0.68-0.85) and good agreement in predicting MGD in PHPT patients. Also, 65 points was recommended as a cut-off value, with specificity = 0.94 and sensitivity = 0.50.

Conclusion

US was useful in evaluating MGD. Combining US and clinical features in a nomogram showed good diagnostic performance for predicting MGD.

Value of Old Imaging for Patients Undergoing Parathyroidectomy for Primary Hyperparathyroidism

INTRODUCTION

Although imaging plays no role in diagnosing primary hyperparathyroidism (PHPT), preoperative localization is essential for a focused parathyroidectomy. We hypothesized that reviewing imaging obtained prior to PHPT diagnosis can identify enlarged parathyroid glands and provide information that might potentially impact the preoperative evaluation and intraoperative course of patients undergoing parathyroidectomy.

METHODS

We included adult patients with PHPT who underwent parathyroidectomy between October 2015 and October 2020 and had contrast-enhanced computed tomography (CT) imaging of the lower neck and upper chest obtained prior to diagnosis for unrelated indications. A radiologist reviewed the prediagnosis CTs blinded to subsequent parathyroid localization imaging and operative findings. A surgeon assessed the radiologist's findings in the context of each case to determine the potential impact of information from old imaging on surgical decision-making.

RESULTS

We identified at least one enlarged parathyroid gland on prior contrast-enhanced CT in 30 (75%) of 40 included patients. Despite old imaging enabling correct localization, 60% of these 30 underwent dedicated parathyroid imaging prior to parathyroidectomy. Knowledge of the enlarged parathyroid(s) on prior imaging might have allowed a more focused approach in 10.0% and prompted a more thorough exploration in 13.3%. In the total cohort, reviewing prior imaging could have provided information capable of changing the preoperative evaluation in 52.5% and the operative course in 17.5%.

CONCLUSIONS

The identification of enlarged parathyroid glands on contrast-enhanced CT imaging that predates a diagnosis of PHPT is possible. Prospective studies might verify the impact of these findings on the preoperative evaluation and operative course of patients undergoing parathyroidectomy.

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.