Is dual-phase SPECT/CT with 99mTc-sestamibi better than single-phase SPECT/CT for lesion localization in patients with hyperparathyroidism?

This study aimed to establish an optimal protocol for Tc-sestamibi parathyroid imaging for lesion localization in patients with hyperparathyroidism (HPT).We retrospectively enrolled 35 consecutive patients who underwent dual-phase (at 10 minutes and 120 minutes) Tc-sestamibi parathyroid scintigraphy with single-photon emission computed tomography (SPECT)/computed tomography (CT). Twenty seven patients had primary HPT, and 8 had secondary or tertiary HPT. Three nuclear medicine physicians independently analyzed the parathyroid images for lesion localization at 9 predefined parathyroid locations using the following 4 different image sets blinded to the clinical information:All SPECT or SPECT/CT image sets were analyzed with dual-phase planar images. The image results were compared with the histopathological results after surgery.Dual-phase SPECT/CT showed the highest positive rate of 85.7% in the patient-based analysis and 13.7% in the location-based analysis. Of 35 patients, surgical pathological results were available in 21 (16 adenomas in 16 primary HPTs and 16 hyperplasias in 5 secondary or tertiary HPTs). Dual-phase SPECT/CT showed the sensitivity values of 100% and 84.4% in the patient-based and location-based analysis, respectively, which were the highest sensitivity values among all image sets. In the primary HPT subgroup, dual-phase SPECT/CT showed the highest sensitivity value of 93.8% in the location-based analyses, whereas dual-phase SPECT, early SPECT/CT, and delayed SPECT/CT showed the sensitivity values of 62.5%, 81.3%, and 81.3%, respectively. In the secondary or tertiary HPT subgroup, dual-phase SPECT/CT also showed the highest sensitivity value of 75.0%, whereas early SPECT/CT, delayed SPECT/CT, and dual-phase SPECT showed the sensitivity values of 43.8%, 56.3%, and 68.8%, respectively.Compared with dual-phase SPECT or single-phase SPECT/CT, the dual-phase SPECT/CT imaging protocol for Tc-sestamibi scintigraphy showed the highest positive rate and sensitivity, and was optimal for parathyroid lesion localization.

Effect of ursodeoxycholic acid in facilitating early hepatic clearance of radiotracer among patients undergoing 99mTc-sestamibi myocardial perfusion scintigraphy: A randomized double blind placebo controlled parallel trial.

BACKGROUND: Infra-cardiac tracer activity due to persistent hepatic activity interferes in inferior and infero-septal wall assessment during 99mTc-MIBI SPECT/CT myocardial perfusion scintigraphy (MPS) in evaluation of patients with coronary artery disease. It affects image interpretation with increased study duration. Ursodeoxycholic acid (UDCA) is known to enhance hepatic excretion of bilirubin and bile salts, though its role in enhancing the hepatic tracer clearance in facilitating cardiac imaging is not known. METHODS: This prospective, randomized double-blind, placebo controlled clinical trial of 120 patients, referred for adenosine stress or viability MPS studies were randomized 1:1 to receive either UDCA or placebo. Outcome was quantitative & qualitative improvement in imaging for better interpretation and to reduce the waiting time for scan. RESULTS: 118 participants (59 ± 11.9 years; 84 men) underwent adenosine stress MPS or viability MPS. Sixty participants had UDCA while 58 had placebo intervention. The study showed significant decrease in liver counts with improved myocardial to liver ratio at 30 and 60 minutes in adenosine stress MPS group, and marginally significant alteration in liver counts at 60 minutes in viability MPS group receiving UDCA, resulting in better images. CONCLUSION: UDCA intervention in MPS provides early and better image due to faster hepatic tracer clearance.

Thoracoscopic surgical case of an ectopic mediastinal parathyroid adenoma detected by chance: a case report.

BACKGROUND: Ectopic mediastinal parathyroid tumor (EMPT) is a rare cause of primary hyperparathyroidism (PHPT); it is difficult to resect using the cervical approach. We describe a case of using video-assisted thoracic surgery (VATS) for EMPT resection. CASE PRESENTATION: A 67-year-old woman with a history of postoperative thyroid cancer had no symptoms. She was diagnosed with PHPT and underwent thyroid cancer surgery. She had serum calcium and intact parathyroid hormone (PTH) levels of 11.1 mg/dL and 206 pg/mL, respectively. Chest computed tomography showed a 10-mm nodule in the anterior mediastinum. Technetium-99 m methoxyisobutyl isonitrile scintigraphy showed an abnormal uptake lesion in the anterior mediastinum. She was diagnosed with PHPT caused by EMPT and underwent VATS. The pathological examination confirmed parathyroid adenoma. Her serum calcium and intact PTH levels were normal from 15 min after tumor resection. She has had no recurrence of EMPT. CONCLUSIONS: The VATS approach was effective for the resection of EMPT.

Clinical Value of Tc99m-MIBI SPECT/CT Versus 4D-CT or US in Management of Patients With Hyperparathyroidism.

Localization of parathyroid adenomas for treatment of primary hyperparathyroidism can be challenging. This retrospective study compared single-photon emission computed tomography/computed tomography (SPECT/CT), 4D-CT, and US studies in detection of adenomas prior to surgery. A retrospective chart review was performed on all consecutive patients with parathyroid adenoma presenting to an urban tertiary care medical center. A total of 58 patients (45 female, 13 male) underwent surgery for parathyroid adenoma. Patients aged 28 to 80 years (mean: 58.8) with parathyroid hormone levels ranging from 42 to 424 pg/mL (mean: 168). All patients underwent preoperative SPECT/CT with 20 mCi technetium-99m MIBI (99mTc-MIBI). Fifty-three patients had additional US imaging and 14 patients had 4D-CT scans. Additionally, 34 patients had injection of 20 mCi 99mTc-MIBI on the day of surgery. Pathological correlation was performed. Comparing SPECT/CT versus 4D-CT resulted in sensitivity (77% vs 80%), specificity (71% vs 75%), and accuracy (77% vs 79%). Ultrasound was less sensitive with similar specificity (44%, 86%, respectively). Combination of SPECT/CT and 4D-CT increased sensitivity to 88%, specificity to 100%, and accuracy to 89%. Combining SPECT/CT with US resulted in sensitivity of 85%, specificity of 83%, and accuracy of 85%. Intraoperative localization substantially improved in patients who received preoperative injections. The SPECT/CT remains the best imaging modality for preoperative localization of parathyroid adenomas with high sensitivity. Combining SPECT/CT with US resulted in increased sensitivity and accuracy. For suspicion of ectopic cases or suspicion of unidentifiable adenoma with negative scintigraphy, addition of 4D-CT is recommended. Intraoperative localization and adjunctive imaging may improve surgical management of patients with hyperparathyroidism.

Diagnostic value of ultrasonography and TI-201/Tc-99m dual scintigraphy in differentiating between benign and malignant thyroid nodules.

PURPOSE: To evaluate the performance of ultrasonography (US) and TI-201/Tc-99m dual (Tl/Tc) scintigraphy in differentiating between benign and malignant thyroid nodules. METHODS: Eighty-six patients diagnosed to have a thyroid tumor on postoperative histopathologic examination between June 2009 and February 2017 were included in this retrospective study. A radiologist reviewed the US and Tl/Tc scintigraphy reports along with all available clinical and histopathologic information. On Tl/Tc scintigraphy, a nodule in which uptake was higher in the delayed phase than in the surrounding parenchyma was defined as a delayed accumulation pattern and a nodule in which uptake was higher in the delayed phase than in the early phase was defined as a persistent pattern. The Tl/Tc scintigraphy images were evaluated in a blinded manner to assess reproducibility. A statistical analysis was performed to identify features associated with malignancy. Interobserver variability was calculated using the κ statistic. RESULTS: US had higher sensitivity (81.2%), specificity (88.2%), and positive (96.6%) and negative (53.6%) predictive values than Tl/Tc scintigraphy. An ill-defined margin and microcalcification were independent predictors of a malignant thyroid nodule on multivariate logistic regression (P = 0.003 and P = 0.014, respectively). The persistent pattern had high specificity (85.7%) equivalent to that of US but had lower sensitivity (34.7%). The κ values for the delayed accumulation and persistent patterns were 0.66-0.78 and 0.32-0.50, respectively. CONCLUSIONS: An ill-defined margin and microcalcification on US were independent predictors of a malignant thyroid nodule. A persistent pattern seen on Tl/Tc scintigraphy could contribute to the differential diagnosis.

Usefulness of feature analysis of breast-specific gamma imaging for predicting malignancy.

OBJECTIVES: The purpose of this study was to investigate which feature of the breast-specific gamma imaging (BSGI) uptake in women who were recently diagnosed with breast cancer was associated with malignancy. METHODS: Data on 231 newly diagnosed breast cancer patients who underwent preoperative BSGI were retrospectively reviewed. Feature analysis was done by classifying BSGI uptake into mass, non-mass, or focus/foci. Descriptors for mass, non-mass, or focus/foci were shape, distribution, number, and intensity. BSGI features of known malignancies and lesions that were additionally found by BSGI were correlated with mammographic breast density, histology, hormonal status, and clinical follow-up data obtained over at least 2 years. RESULTS: Among 372 breast lesions from 231 patients, 241 malignancies had been pathologically confirmed prior to BSGI and 131 additional lesions were found on BSGI. Irregular shape was more predictive of malignancy than oval shape (p=0.004) in mass uptake. Linear/ductal distribution was more predictive of malignancy than focal, regional, and segmental distribution (p<0.05) in non-mass uptake. Mammographic breast density was not associated with BSGI features. The lesion to normal ratio (LNR) was higher in the postmenopausal patients than that in the premenopausal patients (p=0.003). CONCLUSIONS: The feature analysis of radiotracer uptake in BSGI is useful in predicting whether breast lesions are malignant or benign. KEY POINTS: • The feature analysis of BSGI uptake is useful in predicting malignancy. • Irregular shape was predictive of malignancy in mass uptake. • Linear/ductal distribution was predictive of malignancy in non-mass uptake.

Minimally elevated preoperative parathyroid hormone level influences the management of primary hyperparathyroidism.

OBJECTIVES/HYPOTHESIS: To determine the effect of preoperative parathyroid hormone (PTH) level on the extent of surgery and the accuracy of parathyroid imaging in primary hyperparathyroidism. STUDY DESIGN: Retrospective cohort. METHODS: Final diagnosis of single-gland adenoma and its location versus multigland disease was established in this retrospective cohort study. Positive predictive value, negative predictive value, and accuracy of imaging were analyzed in relation to preoperative PTH levels. RESULTS: Eighty-seven percent of the 218 patients enrolled in the study underwent unilateral targeted operation and had a 97.9% (95% confidence interval: 95.8%-100%) success rate. However, in patients with PTH <65 pg/mL, 28.6% had bilateral exploration compared to 10.3% in those with PTH ≥65 pg/mL (P = .042). In patients with PTH <65 pg/mL, 7/21 (33.3%) had inaccurate sestamibi findings compared to 24/174 (13.8%) in patients with PTH ≥65 pg/mL (P = .047). CONCLUSIONS: Accuracy of sestamibi drops significantly, by threefold, in patients with mild primary hyperparathyroidism and PTH <65 pg/mL. Patients with PTH < 65 pg/mL have a 2.5-fold higher rate of bilateral operation to identify the hypersecreting gland(s) compared to patients with PTH ≥65 pg/mL. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:1016-1021, 2018.

Feasibility of unilateral parathyroidectomy in patients with primary hyperparathyroidism and negative or discordant localization studies.

The purpose of this study was to examine the feasibility of unilateral parathyroidectomy in patients with primary hyperparathyroidism and negative or discordant localization studies. We included in our study 72 patients with preoperative diagnosis of primary hyperparathyroidism who had negative or discordant preoperative studies. In 66 patients, studies were discordant while in six were both negative. In 40 (55.6 %) patients initial approach was a bilateral exploration. In 32 cases (44.4 %) initial surgery was a unilateral exploration: in 26 conservative approach was successful, in six mini-invasive surgery failed and a bilateral exploration was necessary due to IOPTH negative test (five cases) or to the impossibility to find a pathological gland during exploration (one case). Intra-operative PTH test showed a sensitivity of 93.2 %, a specificity of 92.3 %, and an accuracy of 93.1 %. Multiple gland disease was found in 8 (11.1 %) patients (two double adenoma and six multiple gland hyperplasia). Mean operative time was lower in unilateral exploration group (87.9 ± 43.8 min). Comparing unilateral surgery in negative or discordant studies with 77 consecutive patients who underwent focused surgery with positive and concordant studies, conversion to bilateral exploration rate was statistically significantly higher in the first group (15.6 %). We believe that unilateral parathyroidectomy can be safely performed also in patients with discordant localization studies with a high cure rate; in these cases, however, the use of intra-operative PTH is absolutely necessary. We suggest the need for referral of these patients to high-volume medical centers for thyroid and parathyroid surgery.

A Multimodal Imaging Protocol, (123)I/(99)Tc-Sestamibi, SPECT, and SPECT/CT, in Primary Hyperparathyroidism Adds Limited Benefit for Preoperative Localization.

INTRODUCTION: Focused parathyroidectomy in primary hyperparathyroidism (1°HPT) is possible with accurate preoperative localization and intraoperative PTH monitoring (IOPTH). The added benefit of multimodal imaging techniques for operative success is unknown. METHOD: Patients with 1°HPT, who underwent parathyroidectomy in 2012-2014 at a single institution, were retrospectively reviewed. Only the patients who underwent the standardized multimodal imaging workup consisting of (123)I/(99)Tc-sestamibi subtraction scintigraphy, SPECT, and SPECT/CT were assessed. RESULTS: Of 360 patients who were identified, a curative operation was performed in 96%, using pre-operative imaging and IOPTH. Imaging analysis showed that (123)I/(99)Tc-sestamibi had a sensitivity of 86% (95% CI 82-90%), positive predictive value (PPV) 93%, and accuracy 81%, based on correct lateralization. SPECT had a sensitivity of 77% (95% CI 72-82%), PPV 92% and accuracy 72%. SPECT/CT had a sensitivity of 75% (95% CI 70-80%), PPV of 94%, and accuracy 71%. There were 3 of 45 (7%) patients with negative sestamibi imaging that had an accurate SPECT and SPECT/CT. Of 312 patients (87%) with positive uptake on sestamibi (93% true positive, 7% false positive), concordant findings were present in 86% SPECT and 84% SPECT/CT. In cases where imaging modalities were discordant, but at least one method was true-positive, (123)I/(99)Tc-sestamibi was significantly better than both SPECT and SPECT/CT (p < 0.001). The inclusion of SPECT and SPECT/CT in 1°HPT imaging protocol increases patient cost up to 2.4-fold. CONCLUSION: (123)I/(99)Tc-sestamibi subtraction imaging is highly sensitive for preoperative localization in 1°HPT. SPECT and SPECT/CT are commonly concordant with (123)I/(99)Tc-sestamibi and rarely increase the sensitivity. Routine inclusion of multimodality imaging technique adds minimal clinical benefit but increases cost to patient in high-volume setting.

Effects of Intracoronary Administration of Autologous Adipose Tissue-Derived Stem Cells on Acute Myocardial Infarction in a Porcine Model.

PURPOSE: Adipose-derived stem cells (ADSCs) are known to be potentially effective in regeneration of damaged tissue. We aimed to assess the effectiveness of intracoronary administration of ADSCs in reducing the infarction area and improving function after acute transmural myocardial infarction (MI) in a porcine model. MATERIALS AND METHODS: ADSCs were obtained from each pig's abdominal subcutaneous fat tissue by simple liposuction. After 3 passages of 14-days culture, 2 million ADSCs were injected into the coronary artery 30 min after acute transmural MI. At baseline and 4 weeks after the ADSC injection, 99mTc methoxyisobutylisonitrile-single photon emission computed tomography (MIBISPECT) was performed to evaluate the left ventricular volume, left ventricular ejection fraction (LVEF; %), and perfusion defects as well as the myocardial salvage (%) and salvage index. At 4 weeks, each pig was sacrificed, and the heart was extracted and dissected. Gross and microscopic analyses with specific immunohistochemistry staining were then performed. RESULTS: Analysis showed improvement in the perfusion defect, but not in the LVEF in the ADSC group (n=14), compared with the control group (n=14) (perfusion defect, -13.0±10.0 vs. -2.6±12.0, p=0.019; LVEF, -8.0±15.4 vs. -15.9±14.8, p=0.181). There was a tendency of reducing left ventricular volume in ADSC group. The ADSCs identified by stromal cell-derived factor-1 (SDF-1) staining were well co-localized by von Willebrand factor and Troponin T staining. CONCLUSION: Intracoronary injection of cultured ADSCs improved myocardial perfusion in this porcine acute transmural MI model.

Longitudinal time-dependent effects of irradiation on multidrug resistance in a non-small lung cancer cell line.

Multidrug resistance (MDR) in cancer is known to decrease the therapeutic efficacy of chemotherapy. The effects of irradiation on MDR in cancer cells remain unclear. Tc-99m methoxyisobutylisonitrile (MIBI) exhibits the same ATP-binding cassette (ABC) transporter kinetics as the chemotherapeutic compound doxorubicin. In this study, we investigated the synergistic effects of chemotherapeutics and irradiation [0 Gy: C (control) group; 3, 6, 9, 12 Gy: I (irradiation) group] in the human non-small lung cancer cell line H1299 exhibiting MDR, on MIBI and doxorubicin ABC transporter kinetics, in vitro and in vivo, respectively. In vitro, inhibition of H1299 cell proliferation by irradiation was found to be irradiation dose dependent. The degree and duration of MDR inhibition in vitro in H1299 were also dose dependent. In the cells of both the C group and 3-Gy I group, no significant difference of MIBI accumulation was observed. In the 6-Gy I group, a higher MIBI accumulation was observed at only 7 days after irradiation relative to the C group. A higher MIBI accumulation in the 9- and 12-Gy I groups with a significant difference from the C group was observed at 4 to 14 days after irradiation. A significant negative correlation between intracellular MIBI accumulation and cell replication was found. In vivo, high accumulation and retention of doxorubicin were observed in irradiated tumors in the H1299 xenograft mice group at 4 to 14 days after 9-Gy irradiation compared with the control mice group. These results provide evidence for a synergistic effect of concurrent chemotherapy and radiotherapy.

Coronary spasm after completion of adenosine pharmacologic stress test.

Adenosine is a frequently used pharmacologic stress agent in myocardial perfusion imaging. Its safety profile is well established, and most of its side effects are mild and transient. Coronary vasospasm occurs occasionally during or after adenosine stress test in rare cases, which may lead to seriously adverse outcomes. This study reported 3 such cases after completion of adenosine pharmacologic stress test.

Mediastinal parathyroid adenoma: diagnostic and management challenges.

Primary hyperparathyroidism due to ectopic parathyroid adenomas can pose diagnostic and management challenges, especially when imaging studies have localised the lesions to different sites. We report a case of symptomatic hypercalcaemia due to a mediastinal parathyroid adenoma. Ultrasonography identified a nodule posterior to the right thyroid gland. However, computed tomography and technetium-99m sestamibi scintigraphy revealed an ectopic parathyroid adenoma located in the anterior mediastinum. The adenoma was successfully removed through a median sternotomy. However, postoperatively, the patient developed prolonged symptomatic hypocalcaemia, possibly due to suppression of the normal parathyroid gland function, although the presence of concomitant hungry bone syndrome was possible. The histopathology of the mediastinal mass was consistent with a parathyroid adenoma.

Impact of intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction on left ventricular perfusion and function: a 6-month follow-up gated 99mTc-MIBI single-photon emission computed tomography study.

PURPOSE: We investigated the impact of intracoronary injection of autologous mononuclear bone marrow cells (BMC) in patients with acute ST elevation myocardial infarction (STEMI) on left ventricular volumes, global and regional systolic function and myocardial perfusion. METHODS: The study included 39 patients with first anterior STEMI treated successfully with primary percutaneous coronary intervention. They were randomly assigned to the treatment group or the control group in a 2:1 ratio. The patients underwent baseline gated single-photon emission computed tomography (G-SPECT) 3-10 days after STEMI with quantitative and qualitative analysis of left ventricular perfusion and systolic function. On the following day, patients from the BMC treatment group were subjected to bone marrow aspiration, mononuclear BMC isolation and intracoronary injection. No placebo procedure was performed in the control group. G-SPECT was repeated 6 months after STEMI. RESULTS: Baseline and follow-up G-SPECT studies were available for 36 patients. At 6 months in the BMC group we observed a significantly enhanced improvement in the mean extent of the perfusion defect, the left ventricular perfusion score index, the infarct area perfusion score and the infarct area wall motion score index compared to the control group (p = 0.01-0.04). However, the changes in left ventricular volume, ejection fraction and the left ventricular wall motion score index as well as the relative changes in the infarct area wall motion score index did not differ significantly between the groups. CONCLUSION: Intracoronary injection of autologous mononuclear BMC in patients with STEMI improves myocardial perfusion at 6 months. The benefit in infarct area systolic function is less pronounced and there is no apparent improvement of global left ventricular systolic function.

Diagnostic accuracy of 99mTc-MIBI-SPECT in the detection of lymph node metastases in patients with carcinoma of the tongue: comparison with computed tomography and MRI.

AIM: To compare the diagnostic efficacy of computerized tomography (CT), magnetic resonance imaging (MRI), and Tc-methoxyisobutylisonitrile-single photon emission computed tomography (MIBI-SPECT) for the detection of lymph node (LN) metastases in clinically neck-negative patients (T1-T2N0) with carcinoma of the tongue. MATERIALS AND METHODS: Twenty adult patients (aged 54.75+/-14.57 years) with histopathologically proven carcinoma of the tongue and clinically neck-negative (T1-T2N0) status were included in this study. Before the wide local excision of the primary tumor followed by modified functional neck dissection, all the patients underwent contrast-enhanced CT and MRI and 99mTc-MIBI-SPECT. The SPECT data acquisition (3600 arc, 128 x 128 matrix, 64 projections, 20 s/projection) was performed 15 min after an intravenous injection of 555-740 MBq of 99mTc-MIBI under the dual head gamma-camera (E Cam, Siemens, Erlangen, Germany) using the low-energy, high-resolution, parallel hole collimator. SPECT data reconstruction was achieved by filtered back projection using the Butterworth filter with a critical frequency of 0.5 and power 10.0. Only visual assessment was used for defining a positive lymph nodes (LNs) on reconstructed SPECT images and maximum intensity projection images. Histopathological examination of LNs was performed using hematoxylin and eosin staining. RESULTS: A total of 351 LNs were excised surgically (functional neck dissection) from 20 tongue cancer patients having N0 neck disease. Only nine of 351 LNs were documented as being positive for malignancy on histopathological examination. These nine LNs were distributed in eight of 20 patients. CT, MRI, and MIBI-SPECT could accurately identify one, three, and five LNs, respectively. In one of the eight patients, 99mTc-MIBI-SPECT could not distinguish between two LNs present at the same level, having size of 6.0 and 8.0 mm. In this study, 99mTc-MIBI-SPECT was shown to have better sensitivity/positive predictive values (55.5%/71%) than either CT (11%/33%) or MRI (33%/60%). The histopathologically documented metastatic LNs picked up by CT or MRI were also identified by 99mTc-MIBI-SPECT. CONCLUSION: In this preliminary prospective study, we observed that 40% (8/20) of the clinically neck-negative carcinoma tongue patients harbored metastatic LNs. 99mTc-MIBI-SPECT is a more effective imaging modality in the staging of clinically neck-negative LN metastases in carcinoma tongue as compared with CT or MRI.

Experimental and clinical observations of 99mTc-MIBI uptake correlate with P-glycoprotein expression in lung cancer.

BACKGROUND: 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) has been used as a tumour positive scintigraphic agent for diagnostic purposes. However, the pharmaceutical kinetics and accumulation patterns of 99mTc-MIBI in tumour tissues (both in vitro and in vivo) remained poorly understood. Using human embryonic lung fibroblasts (HLFs) as a control, we investigated the kinetics of 99mTc-MIBI accumulation in four human cancer cell lines. RESULTS: We found that, among the tested groups, the uptake rate (UR) of 99mTc-MIBI in normal lung fibroblast cells was the lowest at 90 min after injection, while the UR of four groups of carcinoma cells increased significantly. A significant change of the UR value was observed under cellular depolarization and hyperpolarization. Interestingly, we found that malonic acid, a respiratory chain inhibitor, could inhibit UR rates by 27% from the lowered level in hyper-potassium condition. We also used a semi-quantitative method to analyse 99mTc-MIBI imaging results from 93 clinical cases of pathologically or cytologically confirmed lung cancer lesions. We found that the UR value of a lung benign lesion group was significantly lower than that of a malignant lesion group. We conclude that the sensitivity, specificity and accuracy of 99mTc-MIBI imaging for the lung occupied cancer lesions were 89.83%, 79.41% and 86.02%, respectively. We also investigated the relationship between P-gp expression and MIBI uptake in 25 clinical cases. CONCLUSION: These observations demonstrate a close relationship between the state of 99mTc-MIBI accumulation and the metabolic level of tumour cells and the P-gp expression. Our data suggest that 99mTcc-MIBI semi-quantitative imaging is useful for the qualitative diagnosis of lung-occupied cancer lesions and may be a potential predictor of the P-gp expression in the clinic.

Underestimation of extent of ischemia by gated SPECT myocardial perfusion imaging in patients with left main coronary artery disease.

BACKGROUND: There have been limited data regarding the value of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for the detection of left main coronary artery disease (CAD). METHODS AND RESULTS: We studied 101 patients with angiographic left main CAD (> or = 50% stenosis) and no prior myocardial infarction or coronary revascularization who underwent gated exercise or adenosine stress technetium 99m sestamibi SPECT MPI. By perfusion assessment alone, high-risk disease with moderate to severe defects (> 10% myocardium at stress) was identified in only 56% of patients visually and 59% quantitatively. Absence of significant perfusion defect (> or = 5% myocardium) was seen in 13% of patients visually and 15% quantitatively. However, by combining visual perfusion data and nonperfusion variables, especially transient ischemic dilation, 83% of patients were identified as high risk. CONCLUSIONS: The findings of this study demonstrate that assessment of perfusion data alone by visual or quantitative SPECT MPI analysis underestimates the magnitude of left main CAD. The combination of perfusion and nonperfusion abnormalities on gated MPI identifies high risk in most patients with left main CAD.