Case Report
Preoperative Parathyroid Radionuclide Scintigraphy in Hyperparathyroidism Col SS Anand*, Lt Col MS Chauhan+, Mr Joginder Singh# MJAFI 2005; 61 : 74-75 Key Words : Hyperparathyroidism; Parathyroid gland; Sestamibi; Unilateral neck exploration
Introduction rimary hyperparathyroidism occurs commonly due to adenomas or hyperplasia of the parathyroid gland and rarely due to parathyroid carcinoma. Preoperative localization of the parathyroid is important to achieve targeted surgical approach i.e. unilateral neck exploration and thus reduce surgical complications and morbidity [1]. We describe a radionuclide imaging study used to achieve accurate localization of the abnormal parathyroid gland using Technetium-99m-sestamibi in a case of primary hyperparathyroidism.
P
Case Report A 50 year old female patient was admitted with pain in right thigh and a solitary nodular swelling left side of neck of 6 months duration. Serum calcium and parathormone levels were found to be raised. X-ray of right thigh revealed a cystic lytic lesion in upper third of shaft of femur. Since the patient’s clinical and biochemical findings were suggestive of primary hyperparathyroidism, the patient was referred for radionuclide imaging studies for confirmation. 20 milli Curie of Tc-99m-MIBI was injected intravenously and anterior cervico-thoracic images were acquired for 10 minutes with a single head Gamma camera with low energy high resolution parallel hole collimator at 10 minutes, 30 minutes, 1 hour, 2 hours and 3 hours post injection. Initial images revealed good concentration of the radiotracer in both lobes of the thyroid with a focal area of radiotracer concentration in the region of upper pole of left lobe of thyroid gland. Delayed images showed persistence of the above focal area of radiotracer concentration with washout of the radiotracer from the thyroid gland suggestive of a parathyroid adenoma in the region of upper pole left lobe of thyroid gland. Based on the clinical presentation and imaging findings, the patient was subjected to left sided unilateral neck exploration and selective parathyroidectomy was carried out. Tissue examination confirmed the presence of parathyroid adenoma.Serum calcium and parathormone levels returned
to normal postoperatively.
Discussion Hyperparathyroidism is characterized by uncontrolled parathormone secretion by one or more hyperfunctioning parathyroid glands located in the thyroid bed or ectopically in the neck or mediastinum. Supernumerary glands are seen in 2.0-6.5% cases [2]. The imaging of hyperparathyroidism has shifted from the detection of skeletal and renal manifestations of hyperparathyroidism to localization of the source of abnormal parathormone. Because of the small size and location of the parathyroid glands, imaging with most modalities remains difficult. Survey of literature reveals detection sensitivity of 70-75% and specificity of 90% for parathyroid adenomas for CT and MRI [3]. Parathyroid radionuclide scintigraphy is based on the concept of physiological localization in tissue using metabolic markers e.g. Selenium-75-methionine and Cobalt-57-vitamin B12. Thallium Technetium Subtraction scan using Thallium-201 and Technetium99m-pertechnetate has also been used to visualize the abnormal parathyroid glands based on differential localization of radiotracers [4]. Thallium-201 is concentrated by hyperfunctioning parathyroid tissue and thyroid tissue whereas Technetium-99m-pertechnetate accumulates only in the thyroid gland with computer generated subtraction images permitting differentiation of thyroid and parathyroid lesions. However, Thallium Technetium Subtraction scan was seen to suffer from technical limitations due to unfavourable dosimetry and low photon energy of Thallium-201. Taillifer et al [5] introduced dual phase single isotope protocol for preoperative parathyroid imaging using Tc99m-sestamibi. Sestamibi was seen to accumulate in both thyroid and parathyroid tissues, however, sestamibi
* Senior Adviser (Nuclear Medicine), #Scientist ‘E’, Army Hospital (R & R), Delhi Cantt-10 +Classified Specialist (Medicine), Command Hospital (Southern Command), Pune -40.
Received : 19.8.2002; Accepted : 22.1.2003
Hyperparathyroidism
75
surgeon to go in for unilateral neck exploration and successfully excise the hyperfunctioning parathyroid gland. Unilateral neck exploration reduces the time for surgery and anaesthesia, surgical morbidity and complications like recurrent laryngeal nerve paralysis [1]. Also, in case of aberrant or ectopic parathyroid glands, preoperative imaging with sestamibi using a large field of view detector, can visualize the aberrant or ectopic gland and reduce the failure rate of surgery and help avoid resurgery. References Fig. 1 : Serial technetium-99m-sestamibi scans in anterior projection showing early visualization of the thyroid and an abnormal focus of radiotracer in the region of upper pole of left lobe of the thyroid with washout of the radiotracer from the thyroid with washout of the radiotracer from the thyroid in 1 hour and radiotracer retention in the left parathyroid adenoma upto 3 hours
was seen to be retained in abnormal parathyroid due to the presence of higher number of mitochondria in parathyroid adenomas / hyperplasia, facilitating their visualization [6]. Chiu et al [7] have suggested that Technetium-99m-sestamibi is sequestrated within the cytoplasm and mitochondria in response to electrical potential generated across the membrane bilayers of both the cell and the mitochondria. The degree of sestamibi avidity by the parathyroid is independent of parathormone levels but depends, in part, on gland size. Tc-99m-sestamibi uptake within a thyroid adenoma or thyroid carcinoma, or a cervical lymph node can produce a false-positive examination. False negative scans occur in patients with parathyroid hyperplasia. The sensitivity and specificity for detecting parathyroid lesions with Technetium-99m-sestamibi scanning was seen to be 90.7% and 98.8%respectively [8]. In our case, we used Technetium-99m-sestamibi dual phase study to successfully detect the presence of the hyperfunctioning parathyroid adenoma which aided the
MJAFI, Vol. 61, No. 1, 2005
1. Arici C, Cheah WK, Ituart PH. Can localization studies be used to direct focused parathyroid operation? Surgery 2001;129:720-9. 2. Flake THM, Sandler MP, Schipper J. Parathyroid Glands. In: Sandler MP, Patton JA, Coleman RE, Gottschalk A, Wackers FJT, Hoffer PB, editors. Diagnostic Nuclear Medicine. 3rd ed. Maryland: Williams and Wilkins, 1996;991-1011. 3. Spritzer CE, Gefter WB, Hamilton R, Greenberg BH, Axel L, Kresel HY. Abnormal parathyroid glands : high resolution MR imaging. Radiology 1987;162:487-91. 4. Ferlin G, Borsato N, Camerant M, Conte N, Zotti D. New perspectives in localizing enlarged parathyroids by technetiumthallium subtraction scan. JNM 1983;24:438-41. 5. Taillefer R. Detection and localization of parathyroid adenomas in patients with hyperparathyroidism using a single radionuclide imaging procedure with technetium 99m-sestamibi. JNM 1992;33:1801-9. 6. Sandrock D, Merino MJ, Norton JA. Ultrastructural histology correlates with results of thallium-201 / technetium-99msestamibi parathyroid subtraction scintigraphy. JNM 1993;34:24-9. 7. Chiu ML, Kronauge JF, Piwnica WD. Effect of mitochondrial and plasma membrane potentials on accumulation of Hexakis (2-Methoxy isobutyl isonitrile) Technetium in cultured mouse fibroblasts. JNM 1990;31:1646-53. 8. Norman JG, Denham D. Cost effectiveness of preoperative sestamibi scan for primary hyperplasia is dependent solely upon the surgeon’s choice of operative procedure. J Am Coll Surg 1998;186:293-6.
Preoperative Parathyroid Radionuclide Scintigraphy in Hyperparathyroidism Col SS Anand*, Lt Col MS Chauhan+, Mr Joginder Singh# MJAFI 2005; 61 : 74-75 Key Words : Hyperparathyroidism; Parathyroid gland; Sestamibi; Unilateral neck exploration
Introduction rimary hyperparathyroidism occurs commonly due to adenomas or hyperplasia of the parathyroid gland and rarely due to parathyroid carcinoma. Preoperative localization of the parathyroid is important to achieve targeted surgical approach i.e. unilateral neck exploration and thus reduce surgical complications and morbidity [1]. We describe a radionuclide imaging study used to achieve accurate localization of the abnormal parathyroid gland using Technetium-99m-sestamibi in a case of primary hyperparathyroidism.
P
Case Report A 50 year old female patient was admitted with pain in right thigh and a solitary nodular swelling left side of neck of 6 months duration. Serum calcium and parathormone levels were found to be raised. X-ray of right thigh revealed a cystic lytic lesion in upper third of shaft of femur. Since the patient’s clinical and biochemical findings were suggestive of primary hyperparathyroidism, the patient was referred for radionuclide imaging studies for confirmation. 20 milli Curie of Tc-99m-MIBI was injected intravenously and anterior cervico-thoracic images were acquired for 10 minutes with a single head Gamma camera with low energy high resolution parallel hole collimator at 10 minutes, 30 minutes, 1 hour, 2 hours and 3 hours post injection. Initial images revealed good concentration of the radiotracer in both lobes of the thyroid with a focal area of radiotracer concentration in the region of upper pole of left lobe of thyroid gland. Delayed images showed persistence of the above focal area of radiotracer concentration with washout of the radiotracer from the thyroid gland suggestive of a parathyroid adenoma in the region of upper pole left lobe of thyroid gland. Based on the clinical presentation and imaging findings, the patient was subjected to left sided unilateral neck exploration and selective parathyroidectomy was carried out. Tissue examination confirmed the presence of parathyroid adenoma.Serum calcium and parathormone levels returned
to normal postoperatively.
Discussion Hyperparathyroidism is characterized by uncontrolled parathormone secretion by one or more hyperfunctioning parathyroid glands located in the thyroid bed or ectopically in the neck or mediastinum. Supernumerary glands are seen in 2.0-6.5% cases [2]. The imaging of hyperparathyroidism has shifted from the detection of skeletal and renal manifestations of hyperparathyroidism to localization of the source of abnormal parathormone. Because of the small size and location of the parathyroid glands, imaging with most modalities remains difficult. Survey of literature reveals detection sensitivity of 70-75% and specificity of 90% for parathyroid adenomas for CT and MRI [3]. Parathyroid radionuclide scintigraphy is based on the concept of physiological localization in tissue using metabolic markers e.g. Selenium-75-methionine and Cobalt-57-vitamin B12. Thallium Technetium Subtraction scan using Thallium-201 and Technetium99m-pertechnetate has also been used to visualize the abnormal parathyroid glands based on differential localization of radiotracers [4]. Thallium-201 is concentrated by hyperfunctioning parathyroid tissue and thyroid tissue whereas Technetium-99m-pertechnetate accumulates only in the thyroid gland with computer generated subtraction images permitting differentiation of thyroid and parathyroid lesions. However, Thallium Technetium Subtraction scan was seen to suffer from technical limitations due to unfavourable dosimetry and low photon energy of Thallium-201. Taillifer et al [5] introduced dual phase single isotope protocol for preoperative parathyroid imaging using Tc99m-sestamibi. Sestamibi was seen to accumulate in both thyroid and parathyroid tissues, however, sestamibi
* Senior Adviser (Nuclear Medicine), #Scientist ‘E’, Army Hospital (R & R), Delhi Cantt-10 +Classified Specialist (Medicine), Command Hospital (Southern Command), Pune -40.
Received : 19.8.2002; Accepted : 22.1.2003
Hyperparathyroidism
75
surgeon to go in for unilateral neck exploration and successfully excise the hyperfunctioning parathyroid gland. Unilateral neck exploration reduces the time for surgery and anaesthesia, surgical morbidity and complications like recurrent laryngeal nerve paralysis [1]. Also, in case of aberrant or ectopic parathyroid glands, preoperative imaging with sestamibi using a large field of view detector, can visualize the aberrant or ectopic gland and reduce the failure rate of surgery and help avoid resurgery. References Fig. 1 : Serial technetium-99m-sestamibi scans in anterior projection showing early visualization of the thyroid and an abnormal focus of radiotracer in the region of upper pole of left lobe of the thyroid with washout of the radiotracer from the thyroid with washout of the radiotracer from the thyroid in 1 hour and radiotracer retention in the left parathyroid adenoma upto 3 hours
was seen to be retained in abnormal parathyroid due to the presence of higher number of mitochondria in parathyroid adenomas / hyperplasia, facilitating their visualization [6]. Chiu et al [7] have suggested that Technetium-99m-sestamibi is sequestrated within the cytoplasm and mitochondria in response to electrical potential generated across the membrane bilayers of both the cell and the mitochondria. The degree of sestamibi avidity by the parathyroid is independent of parathormone levels but depends, in part, on gland size. Tc-99m-sestamibi uptake within a thyroid adenoma or thyroid carcinoma, or a cervical lymph node can produce a false-positive examination. False negative scans occur in patients with parathyroid hyperplasia. The sensitivity and specificity for detecting parathyroid lesions with Technetium-99m-sestamibi scanning was seen to be 90.7% and 98.8%respectively [8]. In our case, we used Technetium-99m-sestamibi dual phase study to successfully detect the presence of the hyperfunctioning parathyroid adenoma which aided the
MJAFI, Vol. 61, No. 1, 2005
1. Arici C, Cheah WK, Ituart PH. Can localization studies be used to direct focused parathyroid operation? Surgery 2001;129:720-9. 2. Flake THM, Sandler MP, Schipper J. Parathyroid Glands. In: Sandler MP, Patton JA, Coleman RE, Gottschalk A, Wackers FJT, Hoffer PB, editors. Diagnostic Nuclear Medicine. 3rd ed. Maryland: Williams and Wilkins, 1996;991-1011. 3. Spritzer CE, Gefter WB, Hamilton R, Greenberg BH, Axel L, Kresel HY. Abnormal parathyroid glands : high resolution MR imaging. Radiology 1987;162:487-91. 4. Ferlin G, Borsato N, Camerant M, Conte N, Zotti D. New perspectives in localizing enlarged parathyroids by technetiumthallium subtraction scan. JNM 1983;24:438-41. 5. Taillefer R. Detection and localization of parathyroid adenomas in patients with hyperparathyroidism using a single radionuclide imaging procedure with technetium 99m-sestamibi. JNM 1992;33:1801-9. 6. Sandrock D, Merino MJ, Norton JA. Ultrastructural histology correlates with results of thallium-201 / technetium-99msestamibi parathyroid subtraction scintigraphy. JNM 1993;34:24-9. 7. Chiu ML, Kronauge JF, Piwnica WD. Effect of mitochondrial and plasma membrane potentials on accumulation of Hexakis (2-Methoxy isobutyl isonitrile) Technetium in cultured mouse fibroblasts. JNM 1990;31:1646-53. 8. Norman JG, Denham D. Cost effectiveness of preoperative sestamibi scan for primary hyperplasia is dependent solely upon the surgeon’s choice of operative procedure. J Am Coll Surg 1998;186:293-6.
