CT-MIBI image fusion: a new preoperative localization technique for primary, recurrent, and persistent hyperparathyroidism

BACKGROUND: Successful minimally invasive or imaging-guided operations in patients with primary, recurrent, and persistent hyperparathyroidism are based on the reliability of preoperative parathyroid localization studies. The CT-MIBI image fusion promises a higher diagnostic accuracy than current imaging procedures. The aim of our study was to assess its reliability in correctly detecting enlarged parathyroid glands. METHODS: In a prospective study 24 consecutive patients underwent CT-MIBI image fusion as preoperative parathyroid localization procedure. The results of technetium 99m sestamibi single photon emission computed tomography (MIBI-SPECT) alone, today the standard method in parathyroid imaging, and CT-MIBI image fusion were analyzed by a blinded reviewer, and the imaging results were compared with the intraoperative findings. RESULTS: For CT-MIBI image fusion a sensitivity of 93% and a specificity of 100% in correctly detecting the position of enlarged parathyroid glands was calculated and compared with a sensitivity of MIBI-SPECT of 31% and a specificity of 87% (P<.001). This new imaging technique enabled us to successfully treat 22 of our patients (92%) with imaging-guided surgery. Twenty (83%) underwent unilateral or minimally invasive operations. CONCLUSIONS: CT-MIBI image fusion appears to be superior to MIBI-SPECT in preoperative parathyroid imaging. CT-MIBI image fusion can be performed on existing CT- and MIBI-SPECT units. We recommend this method for preoperative localization in patients with primary, recurrent and persistent hyperparathyroidism.     

Virtual neck exploration in patients with hyperparathyroidism and former cervical operations

BACKGROUND: In surgery for primary hyperparathyroidism, preoperative localization together with intraoperative parathyroid hormone assay is important when minimal invasive operations of the parathyroid glands are intended. In cases of reoperation, correct localization of the abnormal parathyroid glands is extremely instrumental. Computed tomography (CT)-(99m)Tc-sestamibi (MIBI)-single photon emission computed tomography (SPECT) image fusion allows for a virtual exploration of the neck by showing the suspected gland three-dimensionally with all the anatomic landmarks in correct position. The aim of this study was to evaluate whether CT-MIBI-SPECT image fusion is superior to MIBI-SPECT alone in detecting abnormal parathyroid glands in patients with previous neck surgery. PATIENTS AND METHODS: In a prospective study, CT-MIBI-SPECT image fusion for preoperative localization was performed in 28 patients with hyperparathyroidism and previous neck surgery. Twenty-one patients had thyroidectomy and seven patients had surgery for hyperparathyroidism. The results of MIBI-SPECT alone and CT-MIBI-SPECT image fusion were compared in these patients. The outcome and the exact predicted position, not just the predicted side, were correlated with intraoperative findings. RESULTS: CT-MIBI-SPECT image fusion was able to predict the exact position of the abnormal gland in 24 of 28 patients (86%), whereas MIBI-SPECT alone was successful in 12 of 28 cases (43%, p < 0.004) only. CT-MIBI-SPECT image fusion detected all three pathologic glands in their ectopic position. With MIBI-SPECT alone, just one ectopic pathologic gland was found. CONCLUSION: This study provides evidence that CT-MIBI-SPECT image fusion is superior to MIBI-SPECT alone in preoperative localization of enlarged parathyroid glands in patients with hyperparathyroidism and previous neck surgery. This should be kept in mind if the results are compared to earlier studies concerning CT-MIBI-SPECT image fusion.     

Surgical therapy for primary hyperparathyroidism in patients with previous thyroid surgery

BACKGROUND: In patients with primary hyperparathyroidism (HPTH) and previous thyroid operations, complications of parathyroidectomy are more frequent than in patients undergoing initial neck surgery. The aim of this study was to investigate the value of preoperative imaging with regard to its influence on the surgical strategy. METHODS: We retrospectively analyzed 17 patients with primary HPTH and previous thyroid surgery. Preoperatively 16 patients underwent sonography and/or scintigraphy. RESULTS: Sonography had an overall accuracy to correctly localize enlarged parathyroid glands of 80%, and scintiscanning had overall accuracy of 78.6%. The accuracy of localization was increased up to 84.6% if both diagnostic procedures were applied. In patients with normal thyroid residues the accuracy of sonography was 85.7%, and it was 100% if scintiscanning was used. CONCLUSIONS: Preoperative localization techniques in patients with primary HPTH and previous thyroid surgery have high accuracy. This allows for an imaging-directed operative strategy, thus preventing unnecessary bilateral neck explorations, which carry a high risk of recurrent laryngeal nerve injury.     

Accuracy of Preoperative Pinhole Subtraction Single Photon Emission Computed Tomography for Patients with Primary and Recurrent Hyperparathyroidism in an Endemic Goiter Area

Purpose Bilateral parathyroid exploration is still the standard therapeutic procedure for primary and recurrent hyperparathyroidism (HPTH). Since a unilateral surgical strategy that reduces surgical complications should not increase the risk of missing enlarged parathyroid glands, reliable preoperative imaging is the first requirement for this approach. This study was conducted to assess the accuracy of preoperative ^99mTcO₄-²⁰¹T1 pinhole subtraction single photon emission computed tomography (SPECT) compared with sonography.Methods The study population consisted of 15 patients with primary (n = 13) or recurrent (n = 2) HPTH who underwent preoperative ^99mTcO₄-²⁰¹T1 pinhole subtraction SPECT. Preoperative sonography was also done in 14 of these patients.Results ^99mTcO₄-²⁰¹T1 pinhole subtraction SPECT was significantly more accurate than sonography. It had an overall accuracy of 80% in detection of enlarged parathyroid glands. The accuracy of localization increased to 92.3% in patients with solitary adenomas, and to 100% in those with solitary adenomas and no previous parathyroid exploration.Conclusions The high accuracy of preoperative localization with ^99mTcO₄-²⁰¹T1 pinhole subtraction SPECT in patients with primary and recurrent HPTH allows for an imaging-guided unilateral operative strategy in most patients, even those with concomitant nodular goiters. This may reduce the risk of surgical complications and expand the use of minimally invasive techniques in parathyroid surgery.     

The use of radioiodinated toluidine blue for preoperative localization of parathyroid pathology

The efficiency of preoperative radioactive toluidine blue (RTB) scintigraphy for the localization of parathyroid pathology was evaluated prospectively in 69 patients (age range, 15 to 81 years; mean, 56 years) with primary hyperparathyroidism. Four patients have previously undergone negative exploratory surgery. Patients underwent preoperative dual radionuclide parathyroid-RTB/technetium 99m (Tc 99m)-thyroid scintigraphies with a computer-interfaced gamma-camera with a pinhole collimator. Computer-acquired scintigraphic data were analyzed for parathyroid localizations by an RTB-parathyroid/thyroid superposition technique. At surgery, parathyroid adenomas were found in 64 patients (single adenomas in 60 patients; two adenomas in four patients), nine of these adenomas were mediastinal. Four patients had parathyroid hyperplasia. One patient had no parathyroid pathology (negative exploratory surgery). Correlation between the surgical-pathologic findings and the scintigraphic RTB localization studies disclosed a sensitivity of 87%, with a specificity of 94%, and an overall accuracy of 92%. The routine use of preoperative scintigraphic parathyroid-RTB/Tc 99m-thyroid localization has proved to be highly effective, enabling detection of small hyperfunctioning parathyroid glands in normal and ectopic locations in a wide range of weights. In this series a success rate of 98% was achieved on initial and reexploratory surgery for primary hyperparathyroidism.     

Preoperative localization in unilateral parathyroid surgery. A cost-benefit study on ultrasound, computed tomography and scintigraphy

In 50 patients with primary hyperparathyroidism, investigation before initial neck exploration included ultrasonography, computed tomography and 99technetium-201thallium subtraction scintigraphy. The sensitivity for correct preoperative localization was 50%, 54% and 56%, respectively. There was marked inter-observer variation in assessment of ultrasonography and computed tomography, while scintigrams were evaluated by only one person. The scintigraphic sensitivity increased with size of the glands. In cases where correct preoperative localization permitted unilateral parathyroidectomy, the time for surgery and anesthesia was significantly reduced. A cost-benefit analysis, however, revealed that the financial saving from this time reduction was outweighed by the cost of the localization procedures. The authors conclude that investigations for definition of enlarged parathyroid glands are not indicated prior to unilateral parathyroidectomy.     

Minimally invasive parathyroid surgery

The standard bilateral neck exploration in primary hyperparathyroidism (HPTH) has been challenged in the recent years by the general trend toward less invasive surgery. The development of more reliable preoperative imaging techniques such as Sestamibi scanning and high definition ultrasonography coupled with improvements in intraoperative rapid assays of intact parathyroid hormone have allowed unilateral explorations in most patients with primary HPTH. This article reviews the currently available preoperative parathyroid localization studies as well as the currently used minimally invasive parathyroidectomy (MIP) techniques, such as open approaches, radioguided surgery and endoscopic procedures. While some techniques are more popular than others, careful selection of patients with primary HPTH has resulted in comparable cure rates to the standard bilateral parathyroid exploration.     

Value of high resolution real-time ultrasonography in secondary hyperparathyroidism

Thirty-two patients were treated surgically for symptomatic secondary or tertiary hyperparathyroidism, and 27 of these patients had high resolution (10 mHz) real-time ultrasonography before parathyroidectomy. This preoperative localization study identified one or more enlarged hyperplastic parathyroid glands in all but one patient who had not had a previous parathyroid operation, and in five of six patients who did have previous parathyroid operations. In both of the patients in whom no parathyroid glands were identified by ultrasonography the only abnormal enlarged parathyroid glands were those situated within the superior mediastinum. When large glands are not observed by ultrasonography in patients with severe secondary hyperparathyroidism, the glands are usually situated in the superior mediastinum, behind the trachea or esophagus, or deeply within the neck. The size of the parathyroid glands correlated positively with the serum parathyroid hormone level and with the severity of the secondary hyperparathyroidism. Thus, the preoperative identification of parathyroid glands by ultrasonography not only localizes the site of most hyperplastic parathyroid glands (70 percent of patients), but also detects those patients who have enlarged parathyroid glands, elevated serum parathyroid hormone levels, and severe secondary hyperparathyroidism. These are the patients who are thus unlikely to respond to further medical therapy.     

In vitro accumulation of technetium-99m-sestamibi in human parathyroid mitochondria.

BACKGROUND: Technetium-99m-sestamibi (sestamibi) is the imaging agent of choice for preoperative parathyroid localization. The subcellular localization of sestamibi uptake in enlarged parathyroid glands in patients with hyperparathyroidism has not been determined. This study investigated the mechanism of retention of sestamibi by human parathyroid tissue. METHODS: Twenty-three freshly harvested and 15 cryopreserved parathyroid glands excised from patients with primary or secondary hyperparathyroidism were analyzed for subcellular localization of Tc-99m-sestamibi. Tissues were incubated with 100 microCi of sestamibi and isolated for mitochondria by differential centrifugation, and the integrity of subcellular fractions was quantified with the mitochondrial enzyme marker, succinate dehydrogenase. RESULTS: Ninety-two percent of sestamibi activity was associated with mitochondria. Furthermore, after adding the mitochondrial uncoupler, carbonylcyanide m-chlorophenylhydrazone (CCCP), to fresh parathyroid tissues, 84.96% and 73.86% of sestamibi was released from the mitochondrial and tissue fragment components, respectively. In addition, sestamibi activity in the mitochondrial component of cryopreserved human parathyroid tissue decreased to the same amount as the CCCP-treated group. CONCLUSIONS: These data confirm that mitochondrial activity is the major component of sestamibi uptake by human parathyroid tissue in patients with hyperparathyroidism.     

Rapid parathyroid hormone analysis during venous localization

OBJECTIVE: To determine the usefulness of the rapid parathyroid hormone (PTH) assay during venous localization for primary hyperparathyroidism (1 degrees HPTH). SUMMARY BACKGROUND DATA: Remedial exploration for persistent 1 degrees HPTH poses a significant challenge when noninvasive preoperative localization studies are negative. Based on experience with the intraoperative rapid PTH assay, this technique was extrapolated to the interventional radiology suite and generated near real-time data for the interventional radiologist employing on-site hormone analysis, with a 12-minute turnaround time from blood sampling to assay result. METHODS: Between November 1997 and July 2002, 446 patients with 1 degrees HPTH were referred for treatment. Of these, 56 (12.5%) represented remedial patients who had each undergone one or more previous cervical explorations. Noninvasive imaging studies were positive for or suggestive of localized disease in 49/56 (87.5%) of these patients, who therefore proceeded directly to surgical exploration. Seven patients with persistent 1 degrees HPTH and negative noninvasive studies underwent selective venous sampling employing a rapid PTH assay in the interventional suite. RESULTS: Venous localization demonstrated an apparent PTH gradient in six of the seven patients. In three, a subtle gradient demonstrated in near real-time prompted additional sampling, which confirmed an unequivocal hormone gradient. In an additional case, the absence of a gradient on initial sampling prompted further sampling, which was positive. All of the patients were explored, and in five of the six patients with a positive PTH gradient, a parathyroid adenoma (mean weight 636 +/- 196 mg) was resected from a location predicted by venous localization. In the sixth patient with a positive gradient, parathyroid tissue was not identified; however, there was a significant fall in the intraoperative PTH values, and immediate postoperative and follow-up laboratory data at 1 month are indicative of a cure. In the one patient with negative localization, abnormal parathyroid tissue could not be located during surgical exploration. CONCLUSIONS: The rapid PTH assay is a major adjunct for obtaining informative venous localization in patients with persistent 1 degrees HPTH. This information is extremely helpful to the surgeon in this challenging group of patients and resulted in a 100% cure rate when a venous gradient was demonstrated. The authors now employ this technique routinely in remedial patients with negative noninvasive imaging studies.     

An algorithm to maximize use of minimally invasive parathyroidectomy

HYPOTHESIS: Minimally invasive parathyroidectomy (MIP) depends on accurate preoperative localization of abnormal parathyroid glands. If the findings of a technetium Tc 99m sestamibi-labeled single-photon emission computed tomography (SPECT) (hereafter referred to as sestamibi SPECT or scan) are negative or ambiguous, cervical ultrasonography (CUS) may increase the success of preoperative gland localization and MIP, avoiding bilateral neck exploration. DESIGN: We collected data regarding preoperative sestamibi SPECT and CUS for parathyroid gland localization and intraoperative findings. SETTING: Tertiary care university hospital. PATIENTS: From August 1, 2000, through January 31, 2003, 71 patients (12 men and 59 women; mean age, 59 years) with primary hyperparathyroidism underwent preoperative sestamibi SPECT and CUS. Patients with prior or concurrent thyroid surgery, reoperative parathyroid disease, secondary/tertiary hyperparathyroidism, or studies performed at outside hospitals, were excluded. The MIP was performed by 1 surgeon with a 2- to 3-cm incision made on the side of the neck where the abnormal gland was preoperatively located. MAIN OUTCOME MEASUREMENTS: Operative findings were compared with results of preoperative studies to determine the accuracy of sestamibi SPECT and CUS for successful MIP. RESULTS: All 71 patients underwent preoperative sestamibi SPECT and CUS. Sestamibi scanning was accurate in 53 (75%) of 71 patients, whereas CUS was accurate in 40 (56%) in determining the side where the glands were located. Sestamibi scan and CUS findings were negative in 5 patients. These patients underwent planned bilateral neck exploration. Of the remaining 66 patients, MIP was successfully performed in 60 (91%). The CUS was complementary to sestamibi scanning in 9 (15%) of these 60 patients, allowing them to avoid bilateral neck exploration. CONCLUSIONS: A positive sestamibi scan finding is the only preoperative requirement for most patients with primary hyperparathyroidism for MIP. If the sestamibi scan findings are negative or ambiguous, preoperative CUS can localize an additional 14% of enlarged parathyroid glands, further facilitating an MIP in these patients.     

Secondary and tertiary hyperparathyroidism: role of preoperative localization

BACKGROUND: The usefulness of both technetium Tc-99m sestamibi (MIBI) scintigraphy and ultrasonography (USG) scan for the detection of enlarged parathyroid glands secondary to renal hyperparathyroidism is rarely addressed. METHODS: A retrospective study from July 1999 to June 2005 was carried out on patients with secondary and tertiary hyperparathyroidism to determine the role of preoperative localization. RESULTS: In the 5 years, 73 patients with renal hyperparathyroidism underwent initial bilateral neck exploration with total parathyroidectomy. Four patients underwent neck exploration with parathyroidectomy for persistent hyperparathyroidism. Two patients underwent neck exploration with parathyroidectomy for recurrent hyperparathyroidism. For patients with initial secondary/tertiary hyperparathyroidism, MIBI scintigraphy correctly showed 101 of 276 (36.6%) surgically confirmed enlarged parathyroids, whereas USG scan showed 99 of 276 (35.9%) surgically confirmed enlarged parathyroids. For persistent or recurrent secondary/tertiary hyperparathyroidism, MIBI scintigraphy and USG scan had sensitivity of 100 and 50%, respectively. CONCLUSIONS: In conclusion, preoperative localization studies have a limited value when used before first neck exploration in secondary/tertiary hyperparathyroidism because of the poor results in identifying all parathyroid glands. In persistent/recurrent hyperparathyroidism, it may play a useful role in localization of the missed or ectopic parathyroid gland.     

Usefulness of diagnostic imaging in primary hyperparathyroidism

BACKGROUND: In patients with primary hyperparathyroidism, prevention of urinary stone recurrence can be achieved by surgical removal of the enlarged parathyroid gland. To ensure the efficacy of surgery for primary hyperparathyroidism, preoperative localization of the enlarged gland is important. In the present study, usefulness of diagnostic imaging for localization of the enlarged gland was investigated in primary hyperparathyroidism. METHODS: We retrospectively examined the findings of imaging studies and clinical records in 79 patients (97 glands) who underwent surgical treatment for primary hyperparathyroidism at Chiba University Hospital between 1976 and 2000. The detection rates of accurate localization were investigated for imaging techniques, such as ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), thallium-201 and technetium-99m pertechnetate (Tl-Tc) subtraction scintigraphy and 99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy, and analysed in relation to the size and weight of the gland and pathological diagnosis. RESULTS: The detection rates by US, CT, MRI, Tl-Tc subtraction scintigraphy and MIBI scintigraphy were 70%, 67%, 73%, 38% and 78%, respectively. The overall detection rate changed from 50% to 88% before and after 1987. The detection rate of MIBI scintigraphy was superior to Tl-Tc subtraction scintigraphy. CONCLUSION: In primary hyperparathyroidism, improvement of accurate localization of an enlarged parathyroid gland was demonstrated along with recent advances in imaging techniques including MIBI scintigraphy.     

Impact of sonography on surgery for primary hyperparathyroidism

The impact of preoperative sonographic localization of enlarged parathyroid glands was evaluated from the standpoint of operative time and complication rates. There was a reduction in the average time from 135 minutes when findings were false-negative to 111 minutes when findings were positive. The rate of complication was not changed by accurate preoperative localization. When the operative goal is to find all parathyroid glands in every patient, the value of preoperative localization of parathyroid tumors by any current method is slight. Should operative policy favor a search for only one enlarged and one normal gland, or should methods improve to the point that even normal parathyroid glands can be located reliably, noninvasive localization should prove to be useful, safe, and cost-effective, even when it is carried out before initial operation.     

Sensitivity and Utility of Parathyroid Scintigraphy in Patients with Primary Versus Secondary and Tertiary Hyperparathyroidism

Introduction Parathyroid scintigraphy (PS) may be used to localize hyperactive parathyroid glands preoperatively. Performance of PS in the setting of secondary and tertiary hyperparathyroidism (HPT) is not well quantified. The performance of PS in secondary/tertiary HPT versus primary HPT may reflect physiologic as well as radiopharmaceutical kinetic differences between multigland hyperplasia versus adenoma. The aim of this study was to review the performance of PS in secondary/tertiary HPT with a comparison to that for primary HPT. Moreover, we evaluated (1) the sensitivity of PS in detecting enlarged glands, and (2) PS detectability as a function of gland weight. Methods We performed a retrospective review of the Mayo Clinic database from 2000 to 2004. We identified 40 patients with secondary or tertiary HPT as well as a matched control group of 40 patients with primary HPT who had had preoperative PS and underwent parathyroid surgery. Results Parathyroid scintigraphy correctly localized all enlarged glands in 88% of patients in the primary HPT group. PS correctly identified both the number and locations of all hyperplastic glands in only 28% of the secondary/tertiary HPT patients. PS failed to identify one enlarged gland in 23% of the patients and two or more enlarged glands in 40% of the patients. PS correctly detects the largest gland in 88% of the patients with secondary and tertiary HPT. The mean gland weight detectable by PS was 612 ± 120 mg for primary HPT. In secondary/tertiary HPT, glands detected by PS had a mean weight of 950 ± 109 mg, whereas the mean weight was 276 ± 34 mg for undetected glands (P < 0.002). Conclusions Parathyroid scintigraphy is a sensitive study for localizing parathyroid glands preoperatively in primary HPT patients. Its sensitivity is low in secondary and tertiary HPT patients. Thus PS has limited value as a preoperative localization study in secondary/tertiary HPT patients.     

Six hundred fifty-six consecutive explorations for primary hyperparathyroidism

OBJECTIVE: To review the outcomes of 656 consecutive parathyroid explorations performed by a single surgeon and to compare the results of conventional and minimally invasive parathyroidectomy (MIP) techniques. SUMMARY BACKGROUND DATA: Traditional surgery for primary hyperparathyroidism (HPTH) involves bilateral cervical exploration, which is usually accomplished under general endotracheal anesthesia. The MIP technique involves preoperative localization with sestamibi scans, surgeon-administered cervical block anesthesia, directed exploration through a small incision, intraoperative rapid parathyroid hormone assay, and discharge within 2 to 3 hours of surgery. METHODS: Six hundred fifty-six consecutive patients with primary HPTH underwent exploration between January 1990 and March 2001. RESULTS: MIP was used with ever-increasing frequency beginning in March 1998. Four hundred one procedures (61%) were performed using the standard technique and 255 patients (39%) were selected for MIP. The success rate for the entire series was 98%, with no significant differences comparing traditional and MIP techniques. The overall complication rate of 2.3% reflects 3.0% and 1.2% rates in the standard and MIP groups, respectively. MIP was associated with approximately a 50% reduction in operating time, a sevenfold reduction in length of hospital stay, and a mean cost savings of $2,693 per procedure, which represents nearly a 50% reduction in total hospital charges. CONCLUSIONS: A dramatic and sustained shift has occurred in the surgical treatment of primary HPTH: MIP has replaced traditional exploration for most patients.     

Structural analysis of gene marker loci on chromosomes 10 and 11 in primary and secondary uraemic hyperparathyroidism

Background. The genetic molecular anomalies in patients with primary (I°) and secondary (II°) hyperparathyroidism (HPTH) are still largely unknown. In particular, the changes underlying monoclonal growth in the parathyroids of patients with II° HPTH are not well understood. Methods. We screened genomic DNA from a total of 30 patients with I° HPTH and 29 patients with II° uraemic HPTH for possible rearrangement or allelic losses of several gene markers located on chromosome 11p near the PTH gene, namely Ha-ras, IGF-2, WT1, and the PTH gene itself. In addition, two other gene markers, PRAD1 (localized on 11q13) and RET localized on 10q11) were examined for possible structural alterations. Moreover, we used fluorescence in situ hybridization (FISH) which is another technique to detect numerical alterations of chromosome 11. Results. The results show that one of 13 patients with I° HPTH (8%) exhibited a rearrangement for the PRAD-1 gene. Loss of heterozygosity of Ha-ras locus was observed in one of 11 uraemic patients with II° HPTH (9%). Three of 10 patients with I° HPTH (30%) and one of 7 patients with II° HPTH (14%) showed an allelic loss of the WT1 gene. No evidence of rearrangement of allelic loss was detected for the IGF-2, PTH or RET genes respectively. Using FISH method, three normal parathyroid glands, six I° HPTH adenomas and eight II° HPTH hyperplastic glands from uraemic patients were studied with centromeric probe for chromosome 11. Monosomy 11 was observed in one case of I° HPTH and in one other case of II° HPTH. Conclusion. Evidence of loss of heterozygosity for several genes located on human chromosome 11p has been found in a series of parathyroid glands from several patients with I° and II° uraemic HPTH, corresponding to monosomy of chromosome 11 11 in some cases.     

Prospective evaluation of the efficacy of technetium 99m sestamibi and iodine 123 radionuclide imaging of abnormal parathyroid glands.

BACKGROUND. Technetium 99m sestamibi is an isonitrile radionuclide imaging agent that, when used with subtraction iodine 123 thyroid scans, has the potential for imaging abnormal parathyroid glands. METHODS. We prospectively evaluated 20 patients with hyperparathyroidism to study the efficacy of Tc 99m sestamibi and 123I subtraction radionuclide scanning for the imaging of abnormal parathyroid glands. All patients underwent neck exploration and histologic confirmation of all parathyroid glands identified. RESULTS. The solitary adenomas in 11 of 16 patients with primary hyperparathyroidism were localized with sestamibi scans. The scans in four of five patients with diffuse parathyroid hyperplasia showed bilateral localization consistent with enlarged glands. The fifth patient previously underwent a subtotal parathyroidectomy, and a fifth supernumerary gland was localized with the sestamibi scan. Four patients had hyperparathyroidism related to kidney disease. Three of these had bilateral localization of enlarged glands. The fourth patient had undergone two previous operations, and a fifth supernumerary gland was localized with the sestamibi scan. CONCLUSIONS. The preliminary data indicate that Tc 99m sestamibi in combination with 123I radionuclide scanning may be useful in the preoperative localization of abnormal parathyroid glands. This technique localized all of the solitary adenomas that were subsequently resected, and in two reoperative cases it identified the remaining solitary gland causing persistent hypercalcemia.     

Enlarged parathyroid glands discovered in normocalcemic patients during thyroid surgery

BACKGROUND: This is a retrospective study analyzing data of normocalcemic patients with enlarged parathyroid glands discovered during thyroid surgery and comparing it with data of patients operated on for proved primary hyperparathyroidism. METHODS: The records of patients with enlarged parathyroid glands (group 1) and those with primary hyperparathyroidism (group 2) were reviewed. RESULTS: There were 11 patients in group 1 and 123 patients in group 2. Enlarged parathyroid glands identified at thyroid surgery were lighter and developed in younger patients. Biochemistry and pathology revealed that these were less hyperfunctioning. Sex, number of diseased glands per patient, and cell type were not statistically different between the 2 groups. CONCLUSIONS: Enlarged parathyroid glands discovered at the time of surgery are mildly hyperfunctioning. They may represent an early pathologic stage responsible for overt primary hyperparathyroidism. We recommend removal of enlarged parathyroid glands found during thyroid operation in normocalcemic patients as long as at least 1 normal parathyroid gland remains.     

Hyperthyroidism after parathyroid exploration

BACKGROUND: We hypothesized that hyperthyroidism after parathyroid exploration may be an underreported phenomenon with a course more severe than recognized previously. METHODS: We examined pre- and postoperative thyroid function and outcomes in 199 consecutive patients who, since March 2000, had parathyroid exploration for primary sporadic hyperparathyroidism (HPTH). We excluded patients with prior thyroid or parathyroid surgery, preoperative thyroid medication, concurrent total thyroidectomy, or follow-up <5 months. RESULTS: Of 125 patients with normal preoperative serum thyroid-stimulating hormone levels, 39 (31.2%) were hyperthyroid postoperatively. Mean thyroid-stimulating hormone levels (mean +/- SD) dropped with operation from 2.0 +/- 1.1 microIU/mL to 1.2 +/- 1.4 microIU/mL (P < .0001). Nineteen patients (15%) reported symptoms 1 to 2 weeks after operation. The clinical course of hyperthyroidism typically was short, but 5 patients (4%) had symptomatic hyperthyroxinemia requiring medical therapy. Hyperthyroidism was independent of age, severity of HPTH, anatomic/pathologic features, operative time, and other measures of operative difficulty, but was associated with lithium therapy, bilateral exploration, and absence of concurrent thyroid lobectomy. CONCLUSIONS: Risk of hyperthyroidism may be underappreciated after routine parathyroid surgery for HPTH. Use of lithium and degree of dissection appear contributory. Patients undergoing parathyroid exploration need counseling and surveillance for hyperthyroidism, which may be reduced by minimizing the extent of parathyroid surgery.