99mTc-MIBI Scan Research Articles

A Patient with Classic Severe Primary Hyperparathyroidism in Whom both Tc-99m MIBI Scintigraphy and FDG-PET Failed to Detect the Parathyroid Tumor

A 24-year-old woman was admitted to our department for further examination of hypercalcemia, a high level of intact parathyroid hormone (PTH) and a right parathyroid tumor. She complained of bone pain throughout her body and was unable to walk due to systemic cystic osteofibrosis, including a brown tumor of the left lower extremities. Neck ultrasonography (US) and magnetic resonance imaging (MRI) revealed a tumor 2 cm in diameter in the upper side of the right thyroid lobe. 99mTc sestamibi (99mTc-MIBI) imaging and F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) were performed to diagnose primary hyperparathyroidism and examination of other parathyroid glands. However, neither imaging modality detected the parathyroid tumor. To confirm the diagnosis, we performed selective venous sampling around the parathyroid and the patient was diagnosed with primary hyperparathyroidism due to a right parathyroid tumor. Resection of the right parathyroid tumor was performed and the pathological diagnosis was parathyroid adenoma. To date, both 99mTc-MIBI and FDG-PET are useful to localize parathyroid tumors. In this case, however, neither modality detected the tumor. Although recent studies state that expression of P-glycoprotein (P-gp) in parathyroid tumors plays an important role in the false-negative results of both 99mTc-MIBI scans and FDG-PET, immunohistological study detected no P-gp expression in the parathyroid tumor in the current case.

Double-Phase Tc-99m MIBI Scintigraphy as a Therapeutic Predictor in Patients with Non-Hodgkin’s Lymphoma

Tc-99m MIBI is a promising agent for the functional characterization of P-glycoprotein expression and the prediction of therapeutic outcome in human tumors. The purpose of this study was to determine whether tumor clearance of Tc-99m MIBI may have a predictive value in the clinical outcome in patients with non-Hodgkin's lymphoma. Seventeen patients with histologically proved non-Hodgkin's lymphoma underwent Tc-99m MIBI scintigraphy before starting chemotherapy. Early and late images were obtained after the injection of 740 MBq (20 mCi) Tc-99m MIBI. Tumor-to-normal soft tissue ratios were measured on early and late images, and the percentage retention (%R) was calculated. These findings were correlated with other prognostic factors. Of all 40 tumor lesions, 22 (55%) showed Tc-99m MIBI tumor uptake, whereas the other 18 (45%) lesions had no uptake. According to the location, the diagnostic accuracy of Tc-99m MIBI scans was 66.7% (12 of 18) for lesions of the head and neck, 66.7% (8 of 12) for those of the chest, and 20% (2 of 10) for those of subdiaphragmatic regions (P = 0.037). The mean %R of complete responders was 91.8 +/- 14.8% and for partial responders or nonresponders it was 65.4 +/- 17.7% (P = 0.014). The %R of Tc-99m MIBI showed a significant negative correlation with the serum lactate dehydrogenase level (r = -0.757), the score of the international prognostic index (r = -0.643), and the Ann Arbor stage (r = -0.733). The slow tumor clearance of Tc-99m MIBI can predict a good response to chemotherapy in patients with non-Hodgkin's lymphoma and differentiate responding and nonresponding tumors early in the course of chemotherapy.

Exploración de ganglios regionales en carcinoma de pene mediante gammagrafía con 99mTc-MIBI

99mTc-MIBI scintigraphy has proven utility as a clinically valuable technique for the diagnosis of various primary and recurrent malignant lesions. We report the case of a 65 year old man with penile squamous cell carcinoma and clinically questionable bilateral inguinal lymph nodes. 99mTc-MIBI scan shows increased focal uptake in both groins and in the right iliac region. The patient underwent penile amputation with bilateral lymphadenectomy. Histopathologic report revealed metastatic lymph nodes in all lymphatic basins seen with 99mTc-MIBI. We conclude that this technique has the potential of supplying clinically relevant information for the diagnosis of regional extension of patients with penile carcinoma.

Comparison of Ga-67, Tl-201 and Tc-99m MIBI Imaging in Lymphoma Patients

Purpose: Ga-67 scintigraphy has been used for the evaluation of tumors, especially lymphoma. Recently, Tl-201 and Tc-99m MIBI were also used to tumor imaging. Tl-201 and Tc-99m MIBI had better physiologic characteristics than Ga-67, so we studied 32 biopsy proven lymphoma patients (male 24, female 8, mean age 46 years) with Ga-67, Tl-201 or Tc-99m MIBI and compared the scan findings. Materials and Methods: Twenty-three of 32 patients were injected 74-111 MBq (2-3 mCi) of Tl-201, before chemotherapy and imaged with dual-headed SPECT (Prism 2000, Picker, USA) at 30 minutes after injection. Delayed images were obtained after 3 hr in 8 patients. Twenty seven of 32 patients were injected 740 MBq (20 mCi) of Tc-99m MIBI and imaged at 30 minutes after injection. 111-185 MBq (3-5 mCi) of Ga-67 was injected in 12 patients and imaged at 48 and 72 hours after injection. Twenty eight patients were diagnosed as non-Hodgkin's lymphoma and others were Hodgkin's lymphoma. Results: Twenty patients were positive on Tl-201 scan and 3 patients showed negative findings. One of these 3 patients, Tc-99m MIBI and Ga-67 scan were positive. Twenty two patients were positive on Tc-99m MIBI scan and 5 patients showed negative findings. One of these 5 patients, Tl-201 was positive and 2 were positive on Ga-67 scan. Ten of 12 patients showed positive findings on Ga-67 scan. The sensitivity of these agents were 83.3%, 87.0% and 81.5% for Ga-67, Tl-201 and Tc-99m MIBI, respectively. The sensitivity was highest in Tl-201 scan, but there were no significant differences among three tests. In this study, there was no significant difference of uptake ratios between early and delayed images of Tl-201. Conclusion: Scintigraphy with Tl-201 and Tc-99m MIBI in lymphoma patients have similar sensitivity with Ga-67.

99mTc-MIBI radio-guided minimally invasive parathyroid surgery planned on the basis of a preoperative combined 99mTc-pertechnetate/99mTc-MIBI and ultrasound imaging protocol.

The aims of this study were: (a) to define the accuracy of a preoperative parathyroid imaging protocol based on the combination of technetium-99m pertechnetate/technetium-99m methoxyisobutylisonitrile (99mTcO4/ 99mTc-MIBI) scan and neck ultrasound (US) in selecting patients with primary hyperparathyroidism (pHPT) eligible for a limited neck exploration, and (b) to investigate the potential role of the intraoperative gamma probe (IGP) in radio-guided minimally invasive surgery. 99mTcO4/99mTc-MIBI subtraction scan was performed by means of potassium perchlorate administration with the aim of effecting rapid 99mTcO4 wash-out from the thyroid. Minimally invasive surgery using an IGP was commenced some minutes following the injection of a low, 70 MBq, 99mTc-MIBI dose. Intraoperative PTH (i-PTH) was measured. On the basis of preoperative imaging, 21 pHPT consecutive patients were selected for a limited neck dissection. In 18 of them, a single parathyroid adenoma was found at surgery and IGP allowed performance of parathyroidectomy through a small, 2-2.5 cm, skin incision with a relatively short surgical duration (mean 38 min). i-PTH rapidly normalised in all cases. In two patients, a parathyroid carcinoma was diagnosed at surgery; consequently, a wide neck exploration associated with a near-total thyroidectomy was performed. No loco-regional metastatic lesions were found and i-PTH rapidly normalised after carcinoma excision. In one patient, i-PTH remained elevated after removal of the enlarged parathyroid gland which was localised by 99mTcO4/99mTc-MIBI scan and US. A bilateral exploration was needed to remove a contralateral enlarged parathyroid gland. Combined, 99mTcO4/99mTc-MIBI scan and US imaging correctly localised a single parathyroid gland in 20/21 patients (95.2%); thus, this protocol appears to be accurate enough for the preoperative selection of pHPT patients eligible for limited neck surgery. Moreover, in these selected patients the IGP seems to be helpful in performing radio-guided minimally invasive surgery.

Measurement of Myocardial Perfusion with Electron Beam Tomography: Comparison with 99m Tc-MIBI Scan

Purpose: To compare the accuracy with which electron beam tomography (EBT) and -MIBI scanning measure myocardial perfusion valve. Materials and Methods: Twenty-two subjects [normal volunteers (n = 6), patients in whom ischemic heart disease was diagnosed (n = 5), and those in whom ischemic heart disease was suspected but who were found to be normal (n = 11)] were involved in this study. EBT was performed after bolus injection of contrast media (50 ml of Iopamiro 370 or Optiray 350, 3 ml/sec). The myocardium was divided into 16 segments according to the classification devised by the American Society of Echocardiography, and each myocardial perfusion value was calculated by post-image processing. A pharmacologic stress test was performed in all subjects except four patients with acute myocardial infarction, and myocardial perfusion reserve ratios were assessed. Single photon emission computed tomography (SPECT) was performed after the injection of 20 mCi of -MIBI. Any segments with moderate to severe photon defect on visual analysis of SPECT were identified and perfusion values determined by EBT in normal and ischemic segments were compared. Results: No difference in myocardial perfusion was found between volunteers and the suspected group. Their perfusion values were 0.710.14 ml/g/min in the resting state and 1.160.24 ml/g/min on the stress test and the myocardial perfusion reserve ratio was, therefore, 1:1.680.38. In ischemic patients, -MIBI scanning revealed a perfusion defect in 28 segments, and on EBT the measurement obtained was 0.540.19 ml/g/min. The remaining 324 perfusion segments shown by SPECT to be normal showed a perfusion value of 0.790.22 ml/g/min on EBT. Conclusion: Compared with -MIBI scanning, the measurement of myocardial perfusion by EBT provides absolute quantification of perfusion value and more detailed anatomic information.

99mTc-MIBI scan in mammary Pagets disease: a case report

Technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) uptake is known to be increased in breast cancer because of increased blood flow from angiogenesis and heightened metabolism. We performed a 99mTc-MIBI scan in a patient with mammary Paget's disease. The patient had underlying invasive cancer in the same side of the breast. 99mTc-MIBI scan exhibited a scintigraphic image of the uptake from the invasive cancer lesion located deeply in the breast toward the epidermis. 99mTc-MIBI showed an uptake in the deeply located invasive cancer lesion as well as nipple lesion. Especially, the delayed phase of Tc-MIBI scan demonstrated the tumor site more accurately. In conclusion, 99mTc-MIBI scan could be a useful adjunct to clinical decision making in the management of Paget's disease of the breast.

Detection of recurrent malignant melanoma with 99mTc-MIBI scintigraphy.

Initial reports suggest that 99mTc-methoxyisobutylisonitrile (MIBI) scanning may be of clinical value in staging patients with malignant melanoma. We carried out a study to evaluate the potential of this technique in the detection of recurrent disease. Whole-body 99mTC-MIBI scans were performed in 81 patients with a history of a surgically excised MM: 28 with known recurrent lesions and 53 during follow-up without evidence of disease. Images started 10 min post-injection, using a dose of 740 MBq. Diagnoses were confirmed by cytological/histological examination or at least one conventional imaging modality. Blinded interpretations of the MIBI scans were performed. Whole-body MIBI scanning correctly detected 68 (92%) of 74 metastatic lesions in the following sites: regional lymph nodes (n=23), non-regional lymph nodes (n=10), skin (n=16), brain/cerebellum (n=6), lung (n=8), bone (n=4) and breast (n=1). The technique failed to detect three subcutaneous regressive lesions (< 1 cm), one liver metastasis, one spleen metastasis and a case of multiple small lesions of the duodenal mucous membrane. In 14 patients the procedure detected previously unknown metastatic lesions. These results suggest that 99mTc-MIBI scanning is an effective imaging modality for whole-body screening of metastatic disease in malignant melanoma patients with the potential to influence treatment planning.

Dynamic imaging: scintimammography

Although mammography remains the technique of choice for the early detection of breast cancer, new emerging breast imaging techniques such as ultrasound, magnetic resonance and radionuclide scanning have been investigated and included in many diagnostic protocols. This overview discusses the current problems related to radionuclide breast imaging trying to define its role in the management of women with suspicious breast lesions at mammography. A number of tumor-imaging agents have been recently used for the differential diagnosis of malignant and benign lesions in radiographically dense breasts and breasts with architectural distortions from prior biopsy or surgery or following radiation therapy. 99mTc-MIBI is the most used tracer which has become the paradigm of this new class of compounds suitable for breast imaging. The current sensitivity and specificity rates for breast scintigraphy with 99mTc-MIBI depend on a number of factors including lesion size and site. Sensitivity and specificity rates and positive and negative predictive values of 92, 89, 81 and 96%, respectively, have been reported in a large series of patients with palpable breast lesions, which figures have been confirmed in many other series. On the contrary, lower sensitivity has been reported for nonpalpable breast abnormalities or for lesions smaller than 1 cm. This observation, confirmed by many authors, implies that a new nonpalpable lesion that is suspicious for malignancy at mammography needs a histologic diagnosis. We also report the results of our recent studies on functional imaging with 99mTc-MIBI of the multidrug resistance phenotype in breast cancer patients. These studies followed an observation that this tracer is a suitable transport substrate for the P-glycoprotein (P-gp) which is commonly associated with the development of a multidrug resistance phenotype. We examined 30 patients with histologically confirmed breast carcinoma who had received no previous chemotherapy or preoperative local irradiation. We found a positive and significant correlation between the efflux rates of 99mTc-MIBI determined by in vivo kinetic analysis and the P-gp levels measured in vitro by quantitative autoradiography in the same tumors ( r=0.62; p<0.001). More recently, we tested whether tumor clearance of 99mTc-MIBI can predict the response to neoadjuvant chemotherapy in patients with locally advanced breast cancer. Thirty-nine patients with stage III disease underwent 99mTc-MIBI scanning before neoadjuvant chemotherapy and the time to half-clearance of the tracer was calculated. The patients then received epirubicin and underwent mastectomy after completing chemotherapy. This study showed that a rapid tumor clearance of 99mTc-MIBI (≤204 min) can predict the lack of tumor response to neoadjuvant chemotherapy with drugs affected by multidrug resistance phenotype in advanced breast carcinoma patients. However, slower tracer clearance (≥204 min) did not guarantee an objective tumor response to chemotherapy in all patients, in agreement with the existence of several P-gp-independent mechanisms of drug resistance. We conclude that the preliminary study of this phenotype would allow to predict the response to (neo)adjuvant chemotherapy and select the appropriate treatment regimen for each patient. Finally, radionuclide breast scanning may be helpful in the differential diagnosis of malignant and benign breast lesions as a guide to subsequent chemotherapy.

Preoperative localization in primary hyperparathyroidism: value of Tc-99m-MIBI scintigraphy

In order to assess the value of scanning with 99mTc-MIBI before surgery in primary hyperparathyroidism (PHP), we performed this procedure in 30 patients with PHP. MIBI imaging findings were: 24 true positive results, three false positive, three false negative (sensitivity: 89%). The 24 true positive results comprised 21 solitary adenomas (one of which was ectopic), one cancer, and two parathyroid hyperplasias. Thus 99mTc-MIBI scanning seems to be useful for the preoperative localization, and for preparing the surgeon to unusual features that could generate surgical failure.

Preoperative localization of enlarged parathyroid glands by 99mTc-MIBI scintigraphy

Recent studies have shown that 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI), a new agent for myocardial perfusion imaging, can be successfully applied to parathyroid imaging. We evaluated the efficacy of 99mTc-MIBI scintigraphy for preoperative localization of enlarged parathyroid glands in patients with hyperparathyroidism. From June 1994 to September 1996, 24 patients with biochemical confirmation of hyperparathyroidism were studied with 99mTc-MIBI scintigraphy prior to operation. Eleven patients had primary hyperparathyroidism (PHPT) and 13 had secondary hyperparathyroidism (SHPT) associated with chronic renal failure, including one patient with recurrent disease after subtotal parathyroidectomy. A positive 99mTc-MIBI scan for an enlarged gland was defined as an area of persistent focal uptake on the delayed image acquired at 150 min after intravenous injection of 600 MBq of 99mTc-MIBI. Of 11 patients with PHPT, 10, were found to have solitary parathyroid adenomas at surgery and one patient had primary hyperplasia. 99mTc-MIBI scintigraphy accurately detected 9 of 10 adenomas and 2 of 3 hyperplastic glands with no false positive results. Both of the two glands that were not detected by 99mTc-MIBI weighed 200 mg. The mean weight of the 11 glands that were visualized was 1264 mg (range 300 approximately 4300 mg). The sensitivity and predictive value positive for PHPT were 84.6% and 100%, respectively. In 13 patients with SHPT, all of 49 parathyroid glands were identified during surgery, with 43 hyperplastic glands and 6 normal-size glands. Of 43 hyperplastic glands, 28 were detected by 99mTc-MIBI and there was significant difference between the mean weight of these 28 glands (999 mg, range 290 approximately 2630 mg) and that of the 15 nonimaged hyperplastic glands (283 mg, range 90 approximately 540 mg). None of the six normal glands were imaged with 99mTc-MIBI. One patient had a false positive scan caused by a thyroid nodule. The sensitivity and predictive value positive for SHPT were 65.1% and 96.6%, respectively. 99mTc-MIBI scintigraphy is an excellent imaging method for localization of enlarged parathyroid glands in patients with hyperparathyroidism, especially with PHPT. However, it has the difficulty to demonstrate enlarged glands smaller than 300 mg in weight.

The use of 99mTc-MIBI scanning in multiple myeloma.

Tc-99m 2 methoxy-isobutyl-isonitrile (99mTc-MIBI), also called Sestamibi, is a safe and effective scanning agent in solid tumours. Its use in imaging lesions in multiple myeloma has been studied in 21 patients with either multiple myeloma (19/21) or monoclonal gammopathy of undetermined significance (MGUS) (2/ 21). 99mTc-MIBI scanning was positive in 14 patients, 13 with active myeloma and one patient with MGUS showing possible transformation to a more accelerated phase. In seven patients 99mTc-MIBI scanning was negative. In four of them, the result was unexpected, as they had the features of active myeloma. All four were either primarily or secondarily resistant to chemotherapy, with high total cumulative doses of doxorubicin. Overexpression of P-glycoprotein associated with multidrug resistance could be a factor, as it has been shown that 99mTc-MIBI is actively eliminated from the cell by P-glycoprotein. With this assumption, sensitivity of the scanning technique in this series is 100%, and the specificity 88%. No toxicity was experienced by any patient. 99mTc-MIBI scanning is a useful adjunct to the investigation of multiple myeloma, and may have potential as an in vivo test for multidrug resistance.

Thyroid Imaging With Tc-99m MIBI in Patients With Solitary Cold Single Nodules on Pertechnetate Imaging

Thyroid imaging was performed in 30 patients with the standard pertechnetate technique, as well as with Tc-99m MIBI using a double-phase acquisition protocol. All patients had normal thyroid function confirmed by hormone measurements and cold solitary thyroid nodules, which were evaluated by pertechnetate scanning. Tc-99m MIBI scans were reported as showing cold (N = 14), warm (N = 7), or hot (N = 9) nodules. Nodule classification was made according to fine needle aspiration biopsy findings in 20 patients. The remaining 10 proceeded to surgery and had histopathologic confirmation of their lesions. Although all cold nodules with Tc-99m MIBI were cystic, six of the warm nodules were benign lesions. No histologically proven benign nodule was hot with Tc-99m MIBI. Of the hot nodules, seven were suspicious for follicular carcinoma with fine needle aspiration biopsy (N = 3), or had histologically proven papillary carcinoma (N = 4). Delayed images in five of seven of these lesions showed nodular retention of the radiopharmaceutical. In conclusion, double-phase Tc-99m MIBI scanning of the thyroid gland could be helpful in the preoperative assessment of patients with cold solitary thyroid nodules in order to evaluate the malignancy probability of these lesions.

Comparison of Tc-99m MIBI and Tl-201 Uptake in Musculoskeletal Lesions

The aim of this study was to make a comparison between the uptake of Tc-99m MIBI and Tl-201 in evaluation of musculoskeletal lesions. Fourteen cases were studied. Each study consisted of a Tl-201 study followed by a Tc-99m MIBI scan. In addition, a whole-body bone scan was performed in each patient to visualize bone metastases. Tl-201 and Tc-99m MIBI uptakes were evaluated by visual assessment and by using lesion-to-background (L/B) ratio. The authors found increased Tl-201 uptake with a mean L/B ratio of 2.81 and less Tc-99m MIBI uptake with a mean L/B ratio of 2.18 in malignant lesions. Both agents showed lower uptake with mean L/B ratios of 1.6 and 1.2 in benign lesions, but there was no statistical difference between the uptakes of either Tl-201 or Tc-99m MIBI in those with malignant and those with benign lesions. In addition, false-positive imaging was observed with both Tl-201 and Tc-99m MIBI. The results demonstrated that Tl-201 and Tc-99m MIBI accumulations in musculoskeletal lesions are not specific for malignancy.

Intraoperative ultrasonography during parathyroidectomy

— C.B., 52 years old, reported a history of recurrent renal colic. The first episode had occurred in 1988 and during the last colic a stone had been passed. The recurrence of renal colics suggested the necessity for metabolic and endocrinological screening. The basal serum parathyroid hormone concentration was 215.1 pg/ml. A sonographic exploration of the neck showed evidence of a hypoechoic mass located on the left side posterior to the thyroid gland. A 99mTC-MIBI scan confirmed the diagnosis of parathyroid adenoma. Surgical exploration of the neck was planned so as to visualize and remove the adenoma. With the help of intra-operative ultrasound a precise localization of the mass was obtained. The procedure was accomplished by means of a linear 5 MHz probe, introduced into a sterile container and positioned over the thyroid gland. After being localized, the adenoma was removed. Intra-operative sonography, repeated at the end of the procedure, confirmed complete removal of the mass.

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We performed myocardial scan using 201TlCl and 99mTc-methoxy isobutyl isonitrile (99mTc-MIBI) in 16 patients of myocardial infarction and compared their diagnostic value. In view of image quality, 99mTc-MIBI scan was superior to 201Tl scan in 11 cases, and 201T1scan was superior in no case. There was no statistically significant difference between 99mTc-MIBI scan and201T1 scan in sensitivity (88.9% and 83.3%, respectively) and specificity (83.9% and 80.6%, respectively) . It is concluded that 99mTc-MIBI enables us to perform high quality myocardial scan and is clinically useful.