The key role of 99mTc-MIBI SPECT/CT in the diagnosis of parathyroid adenoma: a case report

Diagnostic value of Tc-99m-MIBI SPECT/CT in parathyroid carcinoma with lung metastasis: a case report and literature review

Purpose

Parathyroid carcinoma (PC) is an extremely rare disease, typically presenting with marked elevations of serum calcium concentrations and associated with significantly increased parathyroid hormone (PTH) levels. Although it progresses slowly, approximately25% of PC patients have lung metastases. In the present study, we aimed to evaluate the role of technetium-99m methoxy isobutyl isonitrile (Tc-99m-MIBI; sestamibi) SPECT/CT scintigraphy in the preoperative localization of parathyroid adenomas, incidental metastases findings of PC, and ectopic parathyroid tissue.

Methods

We presented a rare case alongside a review of the relevant literature.

Results

We described an unusual case of a 25-year-old female patient with co-occurrence of PC and lung metastasis. The primary PC lesion showed no radioactive uptake, while the lung metastasis presented as a hyperfunctioning nodule, successfully localized using Tc-99m-MIBI SPECT/CT and confirmed through surgical and pathological examination.

Conclusions

This case emphasized the uniqueness of Tc-99m-MIBI SPECT/CT imaging in diagnosing PC and metastatic lesions. The appropriate application of this technique may help avert the aggressive clinical progression of PC.

The role of combined techniques of scintigraphy and SPECT/CT in the diagnosis of primary hyperparathyroidism: A case report

RATIONALE

Primary hyperparathyroidism, usually as a result of a hyperfunctioning parathyroid gland, represents more than 90% cases of patients evaluated for hypercalcemia. Combined techniques of preoperative scintigraphy and SPECT/CT serve as a successful minimally-invasive parathyroidectomy. This recent imaging method provides four-dimensional functional images with advanced contrast resolution which greatly facilitates preoperative localization of parathyroid adenomas.

PATIENT CONCERNS

We presented the case of a male Caucasian patient, aged 67 years, who was investigated for hypercalcemia. Increased levels of parathormone, cervical ultrasonography without pathological changes, and negative planar parathyroid scintigraphy have led to the performance of a parathyroid scintigraphy combined with SPECT/CT.

DIAGNOSES

The diagnosis of right inferior parathyroid adenoma was confirmed by the 99mTc-MIBI-SPECT/CT that revealed on early phase increased radiotracer uptake in the area of projection of the lower third of the right thyroid lobe. The SPECT/CT scan localized this area behind the lower pole of the right thyroid lobe, in the right side of the trachea, with CT correspondent of hypodense lesion, with a maximum diameter of 20 mm.

INTERVENTIONS

During hospitalization, the decision to undergo surgical intervention was taken. The patient underwent surgical intervention, and minimally-invasive right inferior parathyroidectomy was performed.

OUTCOMES

The histopathological examination confirmed the diagnosis and the patient's recovery was complete, with the normalization of parathormone, calcium levels, and metabolic parameters.

LESSONS

Modern combined techniques of scintigraphy and SPECT/CT proved to be of excellent clinical utility in the preoperative diagnosis of primary hyperparathyroidism, localizing a parathyroid tumor undetected by planar scintigraphy alone.

Value of 99mTc-MIBI SPECT/CT parathyroid imaging and ultrasonography for concomitant thyroid carcinoma

PURPOSE

We aimed to assess the frequency of carcinoma in cases with suspected parathyroid adenoma and test the value of Tc-methoxyisobutylisonitrile (Tc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) parathyroid imaging and neck ultrasonography in detecting concomitant thyroid carcinoma.

PATIENTS AND METHODS

We enrolled 741 patients with clinically suspected parathyroid adenoma who underwent Tc-MIBI planer scans and SPECT/CT of the skull base, neck, and thorax; patients also underwent ultrasonography within 1 month before SPECT/CT. Each case with suspected lesion was analyzed and correlated with pathology. We estimated the frequency of carcinoma detection on SPECT/CT performed for suspected parathyroid adenoma. The sensitivity, specificity, and accuracy of detecting thyroid carcinoma were estimated for both SPECT/CT and ultrasonography.

RESULTS

In total, 222 patients with 250 pathology results were assessed. Of these, 54 patients showed carcinoma. With respect to the anatomical distribution of the incidental findings, 19 (35.19%) had parathyroid carcinoma, 20 (37.04%) had papillary thyroid carcinoma, three (5.56%) had follicular thyroid carcinoma, six (11.11%) had medullary thyroid carcinoma, and six (11.11%) had other carcinomas. For thyroid carcinoma detection, the sensitivity, specificity, and accuracy were 35.71, 88.16, and 80.49% for SPECT/CT and 73.81, 95.10, and 91.99% for ultrasonography, respectively.

CONCLUSION

The frequency of carcinoma is high on Tc-MIBI SPECT/CT performed for suspected parathyroid adenoma. Although Tc-MIBI SPECT/CT plays an important role in the diagnosis and location of parathyroid adenoma, ultrasonography appears to be more suitable for identifying a concomitant thyroid carcinoma. This may vitally influence the choice of therapeutic regimen in patients with primary hyperparathyroidism.

The chloride/phosphate ratio combined with alkaline phosphatase as a valuable predictive marker for primary hyperparathyroidism in Chinese individuals

The chloride/phosphate ratio (Cl/PO4) has been suggested to have a role in primary hyperparathyroidism (PHPT), but the associations between Cl/PO4 combined with ALP level and PHPT has not been well-studied. Our aim was to investigate the predictive value of combination Cl/PO4 with ALP for PHPT. A cross-sectional retrospective analysis was conducted to examine 172 patients diagnosed with PHPT categorized into two groups: normocalcaemic primary hyperparathyroidism (NPHPT) group and hypercalcaemia PHPT group. We found that Cl/PO4 levels and ALP levels in the NPHPT and hypercalcaemia PHPT group were both significantly higher than normal controls. Cl/PO4 and ALP levels were an independent risk factor for PHPT. Cl/PO4 combined with ALP increased the receiver-operating characteristic curves (ROC-AUC) and the diagnostic value in NPHPT and hypercalcaemia PHPT group (0.913; 95% CI, 0.744-1.000 and 0.932; 95% CI, 0.897-0.966, respectively), specificity of 92.8% and sensitivity of 98%. In conclusion, combination Cl/PO4 with ALP might be a low-cost, simple, available predictive marker of PHPT in Chinese individuals, particularly Chinese remote region where the method used to measure PTH cannot be done. Moreover, due to serum calcium level in NPHPT, Cl/PO4 combined with ALP level measurement have great potential to predict significant occurrence of NPHPT.