Tc-99m MIBI thoracic SPECT for the detection of intrathoracic tumor masses

Diagnostic Performances of 99mTc-Methoxy Isobutyl Isonitrile Scan in Predicting the Malignancy of Lung Lesions: A Meta-Analysis

We performed a meta-analysis to evaluate the value of technetium-99m methoxy isobutyl isonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) in differentiating malignant from benign lung lesions.The PubMed and Embase databases were comprehensively searched for relevant articles that evaluated lung lesions suspicious for malignancy. Two reviewers independently extracted the data on study characteristics and examination results, and assessed the quality of each selected study. The data extracted from the eligible studies were assessed by heterogeneity and threshold effect tests. Pooled sensitivity, specificity, diagnostic odds ratio (DOR), and areas under the summary receiver-operating characteristic curves (SROC) were also calculated.Fourteen studies were included in this meta-analysis. The pooled sensitivity, specificity, positive and negative likelihood ratio, and DOR of Tc-MIBI scan in detecting malignant lung lesions were 0.84 (95% confidence interval [CI]: 0.81, 0.87), 0.83 (95% CI: 0.77, 0.88), 4.22 (95% CI: 2.53, 7.04), 0.20 (95% CI: 0.12, 0.31), and 25.71 (95% CI: 10.67, 61.96), respectively. The area under the SROC was 0.9062. Meta-regression analysis showed that the accuracy estimates were significantly influenced by ethnic groups (P < 0.01), but not by image analysis methods, mean lesion size, or year of publication. Deek funnel plot asymmetry test for the overall analysis did not raise suspicion of publication bias (P = 0.50).Our results indicated that Tc-MIBI scan is a promising diagnostic modality in predicting the malignancy of lung lesions.

Focal pulmonary uptake during Tc-99m myocardial perfusion SPECT imaging

PURPOSE

To evaluate the incidence and origin of abnormal focal pulmonary uptake during myocardial perfusion SPECT imaging (MSPECT).

METHODS

For evaluation of chest pain, 790 men and 581 women (mean age, 56 +/- 13 years) underwent MSPECT. All of them received adenosine for pharmacologic stress and Tc-99m tetrofosmin (TF, n = 817) or Tc-99m sestamibi (MIBI, n = 554) for myocardial perfusion imaging.

RESULTS

Review of chest radiography with or without computed tomography revealed 111 (8.1%) focal pulmonary diseases. Among them, 38 (34.2%) showed focal pulmonary uptake (TF, 22; MIBI, 16); 27 (30.7%) of 88 showed previous pulmonary tuberculosis; 2 of 10 (20%) benign pulmonary nodules; 4 of 5 (80%) metastatic lung cancers; 2 of 4 (50%) primary lung cancers; and 3 of 4 (75%) pneumonias. No difference in uptake was noted for the two imaging agents. Intensity of uptake did not vary with origin of the uptake. Focal abnormal pulmonary uptake was found in 2.8% of patients undergoing MSPECT and in 34.2% of patients in whom radiological examinations showed regional pulmonary disease. In patients with abnormal pulmonary uptake on MSPECT, 16% had a malignant lesion, whereas 75% of patients with a pulmonary nodule shown on radiography and focal pulmonary uptake on MSPECT had a malignant lesion.

CONCLUSIONS

Although the incidence of abnormal pulmonary uptake during MSPECT was very low, the incidence of malignant lesions in the patients with nodular pulmonary uptake was relatively high.

Usefulness of tc-99m MIBI SPECT in predicting multidrug resistance gene expression levels in non-small cell lung cancer--a preliminary report

In this study we investigated whether Tc-99m hexakis 2-methoxy isobutyl isonitnile (Tc-99m MIBI) single-photon emission computed tomography (SPECT) has a correlation with the multidrug resistance (MDRI) and multidrug resistance-associated protein (MRP1) gene expression levels in non-small cell lung cancer (NSCLC). Fifteen patients with NSCLC were studied. SPECT images were obtained 15 (early) and 120 (delayed) min after injection of Tc-99m MIBI. We chose only one transverse section and set the region of interest over the tumor and out of the body. The mean counts in the tumor on early and delayed images were corrected by using those in the background and represented as Te and Td, respectively. Resected tumor specimens were frozen with liquid nitrogen and each positive control cell line was cultured. After the total ribonucleic acid (RNA) was extracted from specimens and cell lines, the complimentary deoxyribonucleic acid (cDNA) was amplified by the reverse transcription-polymerase chain reaction (RT-PCR) method. Each product was electrophoresed and fluorointensity was measured. The gene expression level was represented as the ratio of that of the positive control cell line. Te and Td indicated a significant correlation with the MDR1 gene expression level (p = 0.015 and p = 0.022), but not the gene of MRP1 (p = 0.100 and p = 0.145). In conclusion, Te and Td are useful parameters in predicting the MDRI gene expression level, but not MRPI in NSCLC.

Double-phase parathyroid scintigraphy in dogs using technetium-99M-sestamibi

The purpose of this study was to evaluate the utility of double-phase parathyroid scintigraphy using 99mTc-sestamibi for detecting and localizing hyperfunctioning parathyroid glands in hypercalcemic dogs. Fifteen hypercalcemic dogs that underwent parathyroid scintigraphy were included in this study: 3 dogs with hypercalcemia of malignancy, and 12 dogs with hyperfunctioning parathyroid tissue (parathyroid adenoma or parathyroid hyperplasia). The presence of parathyroid adenoma or parathyroid hyperplasia was documented by histopathologic examination. In 3 dogs with hypercalcemia of malignancy, parathyroid scintigraphy was negative for hyperfunctioning parathyroid tissue and the scans were classified as true negative. Parathyroid scintigraphy correctly identified the presence and location of hyperfunctioning parathyroid tissue in only 1 of 6 dogs with a parathyroid adenoma. False positive and false negative results occurred in dogs with parathyroid adenomas. Parathyroid scintigraphy failed to detect hyperfunctioning parathyroid tissue in 5 of 6 dogs with parathyroid hyperplasia and were classified as false negative. False positive results were obtained in the remaining dog with parathyroid hyperplasia. Sensitivity of parathyroid scintigraphy for detecting and localizing hyperfunctioning parathyroid tissue was 11%, specificity was 50%, and overall accuracy was 27%. Positive and negative predictive value were 25% and 27%, respectively. Sensitivity for detection of parathyroid adenomas was 25%, and sensitivity for detection of hyperplastic glands was 0 %. Results of this study indicate that double-phase parathyroid scintigraphy does not appear to have acceptable accuracy in detecting hyperfunctioning parathyroid glands in dogs. Due to the poor sensitivity and specificity of the technique in dogs, parathyroid scintigraphy is not recommended for definitive identification of abnormal parathyroid glands as the cause of hypercalcemia in dogs.

A prospective study of Tc-99m MIBI in the differential diagnosis of pelvic masses in female patients

PURPOSE

This study evaluated the feasibility of Tc-99m MIBI scintigraphy in the differential diagnosis of pelvic masses in female patients before operation.

METHODS

Seventy-one patients with pelvic masses were studied with planar imaging over the abdomen and pelvis 5, 15, 30, and 60 minutes after injection of 740 MBq (20 mCi) Tc-99m MIBI. The uptake of the masses was graded, and other abnormal signs, such as intestinal involvement, lymph node involvement, or peritoneal fluid collection, were also considered in image interpretation. An exploratory laparotomy was performed 3 days to 2 weeks after imaging. The scintigraphic diagnosis was compared with that of computed tomography (CT), CA-125 measurement, and pathologic analysis.

RESULTS

Forty-one of 46 pelvic masses with no activity were proved benign. Eighteen of 25 with a fixed, focal uptake were malignant. In 19 of 23 masses, intestinal activity noted within 30 minutes was caused by metastases. All three cases with lymph node involvement and six cases with ascites were confirmed malignant. Combining focal uptake with intestinal involvement correctly indicated 22 of 23 malignant conditions before operation, whereas negative scans identified 41 of 48 benign lesions. Four of seven false-positive lesions had a higher cellular component. The diagnostic performance of Tc-99m MIBI is better than that of CT and CA-125 tests, because CT had eight false-positive and three false-negative results, whereas CA-125 had 12 false-positive and 3 false-negative results, respectively.

CONCLUSIONS

Tc-99m MIBI is useful for differentiating benign and malignant pelvic masses in female patients. A fixed focal uptake or intestinal uptake of the radiotracer suggests malignancy, with diagnostic sensitivity, specificity, accuracy, and positive and negative predictive values of 95.6%, 85.4%, 88.7%, 75.9%, and 97.6%, respectively, in the current prospective study.