Comparative evaluation of 99mTc-MIBI and 99mTc-HMDP scintimammography for the diagnosis of breast cancer and its axillary metastases

The purpose of the present study was to compare scintimammography using technetium-99m hexakis 2-methoxyisobutylisonitrile (MIBI) with that using ^99mTc-hydroxymethylene diphosphonate (HMDP) in the detection of breast cancer and its axillary lesions. The study population comprised 50 consecutive females with breast cancer who were scheduled for surgery. All patients underwent scintimammography with ^99mTc-MIBI and ^99mTc-HMDP. The images were acquired 5 min (early) and 2 h (delayed) after injection of each radiopharmaceutical. Regions of interest were placed over the breast tumour (T), the axillary lesion (A) and the normal ipsilateral breast tissue (N). The two count ratios were calculated, i.e. the tumour to normal breast tissue ratio (T/N) and the axillary lymph node to normal breast tissue ratio (A/N). For the breast tumours, using ^99mTc-MIBI the positive rate was 86% (43/50) for the early and 72% (36/50) for the delayed images. The corresponding values using ^99mTc-HMDP were 72% (36/50) and 40% (20/50), respectively. Histopathological examination revealed metastatic lymph node involvement in 22 patients. For the axillary lesions, using ^99mTc-MIBI the positive rate was 72.7% (16/22) for the early and 54.5% (12/22) for the delayed images. Using ^99mTc-HMDP, the positive rate was only 18.2% (4/22) for the early and 4.5% (1/22) for the delayed images. Using ^99mTc-MIBI, the mean T/N (-SD) ratios on early and delayed images were 2.69ǃ.64 and 2.03ǃ.16, respectively, and the mean A/N (-SD) ratios on early and delayed images were 2.20ǃ.23 and 1.80ǃ.20, respectively. The corresponding values using ^99mTc-HMDP were 1.77ǂ.91, 1.42ǂ.72, 1.27ǂ.63 and 1.08ǂ.25, respectively. The T/N and A/N ratios on the early and delayed ^99mTc-MIBI images were both significantly higher than those obtained using ^99mTc-HMDP. ^99mTc-MIBI scintimammography is more sensitive than ^99mTc-HMDP scintimammography for the detection of breast cancer and its axillary lymph node metastases.     

Uptake and washout of 99mTcV-dimercaptosuccinic acid and 99mTc-sestamibi in the assessment of histological type and grade in breast cancer

This study was performed to investigate the relationship between histological type and grade, with the uptake and washout of 99mTc-hexakis-2-methoxyisobutylisonitrile (99mTc-sestamibi, 99mTc-MIBI) and 99mTcV-dimercaptosuccinic acid (99mTcV-DMSA) in breast cancer. Forty-five patients with histologically proven breast cancer had previously been referred for 99mTcV-DMSA and/or 99mTc-MIBI scintimammography. Twenty-five of them underwent both 99mTcV-DMSA and 99mTc-MIBI scintigraphy in a double phase study. Lateral prone and anterior supine images were acquired at 15 and 60 min after administration of 740-925 MBq of each radiotracer. Uptake ratios and retention index were calculated and correlated with histology and grade of malignancy. Histology showed eight different histotypes: 77.7% were infiltrating ductal or lobular carcinomas. Mammography was definitely positive in 32/45, indeterminate in 10 and negative in three cases (sensitivity 71%). 99mTcV-DMSA was true positive in 37/40 (sensitivity 92.5%) and 99mTc-MIBI in 28/30 (sensitivity 93.3%) breast cancers. Uptake ratios were significantly higher in ductal than in lobular carcinomas on 99mTcV-DMSA and 99mTc-MIBI scintigrams at early and delayed phases. Grade II carcinomas had significantly lower values of retention index (rapid washout) than grade III carcinomas. This finding was statistically significant only on 99mTc-MIBI scans and was observed in ductal and lobular carcinomas. The retention index did not show any significant difference between ductal and lobular carcinomas. Uptake ratios were also not statistically different between grade II and III cancers. It is concluded that 99mTc-MIBI and 99mTcV-DMSA uptake in breast cancer is probably related to histological type and may distinguish ductal from lobular carcinomas. To a certain degree, the washout rate may reflect the histological grade, but since grade is not the only factor influencing this phenomenon it should be explored further in conjunction with other parameters by multivariate analysis in order to clarify eventual indirect correlations.     

Evaluation of planar scintimammography with 99mTc-MIBI in the detection of axillary lymph node metastases of breast carcinoma.

PURPOSE: The aim of our prospective study was to evaluate the role of planar scintimammography with 99mTc-MIBI in detecting axillary lymph node metastases in women with primary breast carcinoma. MATERIAL AND METHODS: Fifty-eight patients underwent scintimammography rior to axillary lymph node dissection. Ten minutes after injection of 700 MBq 99mTc-MIBI, two prone lateral projections were obtained, followed by a supine anterior projection. Sixty-one axillae (3 bilateral) were operated upon and the status of the lymph nodes verified with histopathology. The scintigraphic result was compared to the histopathologic findings. RESULTS: A sensitivity of 67% and a specificity of 80% of planar scintimammography in detecting axillary lymph node metastases were achieved. CONCLUSION: Scintimammography with 99mTc-MIBI is not recommended as a routine method for the detection of axillary lymph node metastases in patients with breast carcinoma.     

^99mTc-MIBI与^99mTc-Octreotide生长抑素受体显像诊断乳腺癌的对比研究

目的:比较99mTcMIBI与99mTcOctreotide生长抑素受体显像对乳腺癌诊断的临床价值。材料和方法:对36例怀疑为乳腺癌的患者术前行99mTcMIBI显像,48小时后行99mTcOctreotide生长抑素受体显像,以术后病理检查结果作为金标准。结果:36例中,25例为乳腺癌,其中11例发生腋窝淋巴结转移;11例患者为乳腺良性病变。两种显像方法对乳腺癌诊断的灵敏度、特异性、准确性分别为92.0%、63.6%、83.3%和92.0%、27.3%、72.2%。结论:99mTcMIBI显像与99mTcOctreotide生长抑素受体显像对乳腺癌均有较好的诊断价值,但99mTcOctreotide生长抑素受体显像诊断特异性较低。由于本研究的病例数有限,有待于进一步的工作深入探讨。     

Evaluation of radiotherapeutic response in non-small cell lung cancer patients by technetium-99m MIBT and thallium-201 chloride SPET

The purpose of this study was to investigate the relationship between technetium-99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) accumulation in tumours and response to radiotherapy in non-small cell lung cancer patients in comparison with the findings obtained using thallium-201 chloride (201Tl). Simultaneous dual single-photon emission tomography (SPET) imaging with 600 MBq 99mTc-MIBI and 111 MBq 201Tl was performed in 31 patients with biopsy- or sputum cytology-proven lung cancer. SPET images were acquired 15 min (early) and 2 h (delayed) after injection, and the early ratio, delayed ratio and retention index were measured. The tumours were classified into two groups on the basis of follow-up computed tomography (CT): responders (at least 50% reduction in tumour size) and non-responders (little or no change in tumour size). The mean (+/-SD) values of early ratio, delayed ratio and retention index using 99mTc-MIBI SPET were 3.0+/-1.1, 2.7+/-1.0 and -9.5+/-12.7, respectively, in responders and 2.4+/-0.7, 2.0+/-0.5 and -18.4+/-9.0, respectively, in non-responders. The corresponding values using 201Tl chloride SPET were 3.7+/-1.0, 4.7+/-1.5 and 24.2+/-22.1 in responders and 3.3+/-1.2, 4.0+/-1.3 and 20.4+/-20.5 in nonresponders. Using 99mTc-MIBI, the delayed ratio and retention index in responders were significantly higher than those in non-responders (P<0.01 and P<0.05, respectively). The results of this study indicate that patients with higher delayed ratio and retention index values using 99mTc-MIBI SPET are likely to respond better to radiotherapy than those with lower values. 99mTc-MIBI SPET may give an indication of the short-term response to radiotherapy in patients with non-small cell lung cancer.     

Characteristics of the myocardial SPECT images of 99mTc-MIBI and 99mTc-teboroxime]

Characteristics of the myocardial distribution of 99mTc-MIBI and 99mTc-Teboroxime was compared with the myocardial distribution of 201Tl. We made summed myocardial images, in which central three short-axis SPECT slices were added. Rectangular region of interest (ROI) was set on each myocardial segment, and mean counts of each myocardial region was obtained using summed short-axis images. The ratio of inferior-to-anterior mean counts (I/A) was 0.69 +/- 0.20 in 99mTc-MIBI and 0.62 +/- 0.16 in 201Tl. The ratio of inferior-to-lateral mean counts was 0.70 +/- 0.18 and 0.65 +/- 0.13, respectively. Both ratios in 99mTc-MIBI were significantly higher than those in 201Tl (p less than 0.05). 201Tl to 99mTc-MIBI ratios of these two values were 1.11 +/- 0.17 (I/A) and 1.08 +/- 0.16 (I/L). The ratios of I/A and I/L of 99mTc-MIBI were about 10 percent higher than those of 201Tl. 99mTc-Teboroxime dynamic short-axis SPECT images of every three-minute were obtained. The ratios of counts in each wall were calculated similarly. After about 8 minutes, gradual increase in hepatic activity can be a cause of quantitative error in the assessment of SPECT images. We obtained the data with a human cardiac phantom. The myocardial phantom filled with 99mTc or 201Tl was placed in the mediastinal portion that is surrounded by the lung (saw dust) and vertebra (plastic bar). The ratio of I/A was 0.79 and I/L was 0.85 in 201Tl. The I/A ratio was 0.93 and I/L was 0.97 in 99mTc. Both ratios in 99mTc were about 15 percent higher than those in 201Tl.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of201Tl-chloride SPECT with99mTc-MIBI SPECT in the depiction of malignant head and neck tumors

OBJECTIVE: Comparison of 201Tl chloride SPECT (TI-SPECT) with 99mTc-MIBI SPECT (MIBI-SPECT) in the depiction of malignant head and neck tumors was prospectively studied. METHODS: Forty-one patients with various tumors of the head and neck were included in this prospective study. Histologically, 36 patients had squamous cell carcinomas, 3 undifferentiated carcinomas, 1 transitional cell carcinoma, and 1 MALT lymphoma. All patients underwent a simultaneous dual-isotope SPECT of the head and neck with 201Tl and 99mTc-MIBI. Dual-isotope SPECT for early (n=41) and delayed acquisition (n=21) was performed. Qualitatively, 3 observers evaluated both TI-SPECT and MIBI-SPECT individually. The interpretation criteria were graded as grade 1 (no abnormal increased uptake) to 5 (definitely increased uptake of a degree equal to or greater than that of normal salivary gland). Statistical analysis of the comparison of Tl-SPECT and MIBI-SPECT was performed. The interobserver difference was evaluated using the kappa-coefficient. Quantitatively, T/N ratio (the ratio of the counts in the tumor divided by that in the normal nuchal muscles) and retention index were compared between TI-SPECT and MIBI-SPECT. RESULTS: On both the early and delayed images, the grades of uptake of the tumor in TI-SPECT were significantly higher than those in MIBI-SPECT by three observers. The grade of Tl-uptake of the tumor on the delayed images was 5 for all observers (kappa-coefficient=1); however, the kappa-coefficient varied from 0.39 to 0.84 in early T1-SPECT, and in early and delayed MIBI-SPECT. Statistical differences in T/N ratio were noted between early TI-SPECT (2.87 +/- 1.19) and MIBI-SPECT (2.48 +/- 1.06), and between delayed Tl-SPECT (2.11 +/- 0.70) and MIBI-SPECT (1.20 +/- 0.48). The retention index or Tl-SPECT (0.81 +/- 0.24) was significantly higher than that of MIBI-SPECT (0.52 +/- 0.15). CONCLUSIONS: The present study qualitatively and quantitatively showed that 201Tl had higher accumulation in the tumor than 99mTc-MIBI in both early and delayed images.     

The role of 99mTc-MIBI scintigraphy in the assessment of MDR1 overexpression in patients with musculoskeletal sarcomas: comparison with therapy response

The occurrence of multidrug resistance (MDR), which is in part due to the overexpression of P-glycoprotein (Pgp), is a major problem in neoadjuvant therapy of malignant musculoskeletal tumours. The aim of this study was to investigate the role of technetium-99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) scintigraphy for functional imaging of the MDR1 phenotype in patients with musculoskeletal sarcomas. We aimed to compare 99mTc-MIBI uptake and washout kinetics with the expression of Pgp and with chemotherapy response. Twenty-five patients (16 males and 9 females, aged between 8 and 65 years) with malignant musculoskeletal tumours were studied. After injection of 555-740 MBq 99mTc-MIBI, dynamic flow images of the involved area were obtained for 3 min, and planar images were acquired at 10 min and 1 h. From the dynamic images, a tumour perfusion index (TPI) was obtained using Patlak-Rutland analysis. Tumour to background (T/B) ratios of both early and delayed images and percent wash-out rate (WR%) of 99mTc-MIBI were calculated. Immunohistochemical analysis of Pgp was performed on biopsy specimens and the degree of expression was graded according to a semiquantitative scoring system, from 0 to 6. After neoadjuvant therapy, tumour response was assessed by examining the ratio of viable cells and by detecting percent necrosis. Scintigraphic results were compared with Pgp status and therapy response. Irrespective of the Pgp status, all patients showed significant perfusion and 99mTc-MIBI uptake in early images. There was not a significant correlation between T/B ratios of early and delayed images and Pgp expression. We observed a positive correlation between WR% and Pgp status (r=0.61, P<0.01), and the wash-out rate of 99mTc-MIBI was significantly higher in patients with high Pgp expression than in those with a low Pgp score (33% +/- 9% vs 17% +/- 9%). Therapy response was determined in 21 of 25 patients, and in only 5 of 21 cases was the percent necrosis more than 90%. Neither Pgp expression rate nor WR% was found to show a significant correlation with percent necrosis in the bulk tumour specimens. In conclusion, the initial uptake of 99mTc-MIBI in bone and soft tissue sarcomas did not correlate with Pgp expression. A relationship was found between the wash-out rate of 99mTc-MIBI and the Pgp score, with a significant difference in WR% being observed between patients with high and patients with low Pgp expression.     

Diagnostic performances of double-phase Tc-99m MIBI scintimammography in patients with indeterminate ultrasound findings: visual and quantitative analyses

The aim of the study was to compare the diagnostic performances of visual and quantitative analyses of double-phase Tc-99m methoxyisobutylisonitrile (MIBI) scintimammography (SMM) in patients with ultrasonographically indeterminate findings. SMM (early: 10 min; delayed: 3 h) was performed on 78 patients (malignant 66, benign 12). For visual analysis, the five-scoring method was used. For quantitative analysis, ratios of early and delayed lesions to non-lesion (L/Ns) were calculated. When a visual grade of over 3 was used as the cut-off value for the detection of primary breast cancer, the sensitivity and specificity were 86.4% and 100%, respectively. The area under the curve (AUC) was 0.972. The optimal L/N ratios were 1.22 for early and 1.1 for delayed images. When early L/N 1.22 was used as the cut-off point, the sensitivity and specificity of SMM were 92.4% and 91.7%, respectively. The AUC was 0.952. When delayed L/N 1.1 was used as the cut-off value, the sensitivity and specificity were 78.8% and 91.7%, respectively. The AUC was 0.863. Visual interpretation and early L/N were superior to delayed L/N for the detection of breast cancer. This study suggests the possible diagnostic role of visual and quantitative analyses of double-phase SMM for differentiating malignant breast lesions in patients with ultrasonographically indeterminate findings. This work was supported by Pusan National University Research Grant     

Comparison of planar and SPECT scintimammography with 99mTc-sestamibi in the diagnosis of breast carcinoma

PURPOSE: To compare results of planar and SPECT breast imaging with 99mTc-MIBI in detecting primary breast cancer. MATERIAL AND METHODS: Twenty-six consecutive patients with 34 suspected breast lesions underwent both planar and SPECT scintimammography. Ten minutes after injection of 700 MBq 99mTc-MIBI, 2 prone lateral projections were obtained, followed by a supine anterior projection. Forty minutes after injection, a SPECT study was done. All lesions were operated upon and verified with histopathology. RESULTS: A sensitivity of 85% and specificity of 88% of planar scintimammography in diagnosis of primary breast lesions were achieved. The corresponding values for SPECT were 61% and 64%. CONCLUSION: The diagnostic accuracy of planar scintimammography was not improved by using SPECT imaging.     

Correlation of 99mTc-sestamibi uptake with blood-pool and osseous phase 99mTc-MDP uptake in malignant bone and soft-tissue tumours

Technetium-99m-sestamibi (99mTc-MIBI) imaging is a well-established modality in oncologic investigations. The current study aimed to investigate whether any relationship could be found between 99mTc-MIBI uptake and local perfusion in malignant bone and soft-tissue tumours. It also aimed to compare 99mTc-MIBI images with those of technetium-99m-methylene diphosphonate (99mTc-MDP) bone scintigraphy with regard to the activity distribution pattern, intensity and lesion extension. The study group included 24 patients with various bone and soft-tissue tumours. Three-phase bone scintigraphy and 99mTc-MIBI studies were performed within the same week before any surgical and therapeutic intervention. Images were evaluated visually and quantitatively using regions of interest (ROIs) over the lesion and adjacent normal tissue. The 99mTc-MIBI study was positive with varying degrees of uptake (range, 1.4-5.3). The mean 99mTc-MIBI uptake and 99mTc-MDP blood-pool and osseous phase activity ratios were 2.5 +/- 0.5, 2.8 +/- 1.0 and 5.5 +/- 4.0, respectively. The correlation between the 99mTc-MIBI uptake and blood-pool ratios was 0.70 (P<0.05). While activity distribution patterns were in agreement in 99mTc-MIBI and blood-pool images in the majority of cases, 99mTc-MIBI better delineated tumour viability and extension in five cases. In conclusion, 99mTc-MIBI accumulation shows a reasonable correlation with blood-pool uptake assuming the presence of multifactorial mechanisms in addition to local hyperaemia. Better delineation of tumour outlines and cellular activity seems to be an advantage of 99mTc-MIBI scintigraphy which may be helpful in the evaluation of musculoskeletal tumours.     

Comparison of early and delayed quantified indices of double-phase (99m)Tc MIBI scintimammography in the detection of primary breast cancer

PURPOSE: To compare the diagnostic accuracy and incremental diagnostic role of quantitative indices of early and delayed lesion to non-lesion ratios (L/Ns) in the detection of primary breast cancer. MATERIAL AND METHODS: Double-phase (99m)Tc MIBI scintimammography (SMM) (early 10 min, delayed 3 h) was performed after injection of 750 MBq of (99m)Tc MIBI in 446 highly suspected breast cancer patients (malignant: 311, benign: 135). For visual analysis, five scoring methods were used, and, for quantitative analysis, early and delayed L/Ns were calculated. Receiver operating characteristic curve (ROC) analyses were performed to determine the optimal visual grade, and to calculate cut-off values of quantitative indices for differentiation of malignant and benign diseases and to investigate whether the quantitative indices could provide incremental diagnostic values in addition to visual analysis. RESULTS: Optimal visual grades were above 4 and 5 in the detection of breast cancer. Sensitivity was 84.2% and specificity 79.3%; the area under the curve (AUC) was 0.832 (95% CI, 0.794-0.866) and standard error was 0.019. Early and delayed L/Ns of malignant breast disease were significantly higher than those of benign disease (early: 2.01 +/- 0.99 versus 1.13 +/- 0.26 (P < 0.001); delayed: 1.68 +/- 0.69 versus 1.11 +/- 0.23 (P < 0.001)). The optimal L/Ns for the detection of primary breast cancer were 1.27 for early and 1.12 for delayed imaging. When early L/N 1.27 was used as cut-off value for the detection of primary breast cancer, the sensitivity of SMM was 77.8% and specificity 85.2%. The AUC was 0.856 (95% CI, 0.820-0.888). When delayed L/N 1.12 was used, sensitivity and specificity were 81.4% and 78.5%, respectively. The AUC was 0.834 (95% CI, 0.796-0.867). The ROC comparison of early and delayed L/N showed no statistical difference in the detection of malignant breast disease (P=0.403). When the delayed L/N was added to the early one, early plus delayed quantitative analysis (E+D) showed 86.5% sensitivity and 74.8% specificity. However, the AUCs of E+D (0.854, 95% CI, 0.767-0.842) and early L/N (E) (0.856) showed no statistical difference (P=0.614). When grades 4 and 5 were used as cut-off visual grade, sensitivity and specificity were 84.2% and 79.3%, respectively. When the E was added to visual grade, visual plus early L/N (V+E) showed 89.4% sensitivity and 77% specificity. The AUC of V+E (0.867, 95% CI, 0.832 0.897) was significantly higher than that of visual analysis (V) (0.832, 95% CI, 0.794-0.866, P < 0.001). When the delayed L/N (D) was added to visual grade, visual plus delayed L/N (V+D) showed 89.4% sensitivity and 74.1% specificity. The AUCs of V+D (0.852, 95% CI, 0.816-0.884) and V revealed no statistical differences (P = 0.052). CONCLUSION: From this study, the optimal visual grades for diagnosis of breast cancer were grades 4 and 5; the cut-off values of L/Ns were 1.27 for early and 1.12 for delayed imaging. It was also found that early L/Ns provide incremental value in addition to visual analysis. However, delayed L/N revealed no incremental value. Therefore, the delayed image should not be routinely performed for purposes of primary breast cancer detection     

99mTc-MIBI SPECT in small cell lung cancer patients before chemotherapy and after unresponsive chemotherapy

We evaluated the accumulation of 99mTc-MIBI in small cell lung cancer patients before chemotherapy and after unresponsive chemotherapy. The pre-chemotherapeutic group included 22 newly diagnosed patients. These patients underwent a 99mTc-MIBI SPECT study before starting chemotherapy. After chemotherapy, based on changes in tumor size, three different patterns of response (complete remission: CR, partial remission: PR and no change: NC) were defined. The post-chemotherapeutic group included 11 patients after chemotherapy who did not respond to chemotherapy. These patients underwent a 99mTc-MIBI SPECT study after completion of chemotherapy. SPECT images were acquired 15 min (early) and 2 hr (delayed) after injection of 99mTc-MIBI. With a region of interest technique, the early ratio, delayed ratio and retention index were calculated. Early and delayed ratios in pre-chemotherapeutic patients were significantly higher than those in post-chemotherapeutic patients. There were no significant differences between the pre-chemotherapeutic and post-chemotherapeutic patients in the retention index. In the pre-chemotherapeutic patients, early and delayed ratios for the CR and PR groups were significantly higher than those for the NC group. There were no significant differences in the retention index with respect to the tumor response. 99mTc-MIBI might be useful for evaluating the tumor chemosensitivity in patients with small cell lung cancer.     

99 Tcm-MIBI乳腺显像诊断乳腺癌评判方法的探讨

目的：探讨^99Tc^m-甲氧基异丁基异腈（MIBI）显像诊断乳腺癌的评判方法。方法：对100例乳腺肿瘤患者行^99Tc^m-MIBI平面显像,分别计算肿瘤与健侧对应部位（T／N）、肿瘤与胸骨（T／S）、肿瘤与心脏（T／H）的放射性比值,比较三者诊断乳腺癌的价值,确定最佳临界点,观察不同时相显像诊断乳腺癌的差异。结果：T／N检测乳腺癌的灵敏度、特异性和准确性最好,分别为84％、90％和87％;T／H分别为70％（P＞0．05）、72％（P＜0．05）、71％（P＜0．01）;T／S分别为58％（P＜0．01）、78％（P＞0．05）和68％（P＜0．01）。T／N比值在1．1－1．2间诊断乳腺癌的准确性最高。10或30min显像诊断乳腺癌结果无差异。结论：^99Tc^m-MIBI乳腺显像诊断乳腺癌较合适的评判方法为：选择T／N为判断指标,比值取1．1－1．2,显像时间为10或30min均可。     

Uptake of99mTc-tetrofosmin,99mTc-MIBI and201TI in malignant thymoma

99mTc-tetrofosmin, Thallium-201-chloride (201Tl) and 99mTc-MIBI imagings were performed in a patient with malignant thymoma. Tracer uptake in the primary tumor was demonstrated. The tumor-to-background ratios of planar and SPECT imagings were 1.60 and 1.98 for 99mTc-tetrofosmin, 1.12 and 2.09 for 201Tl, and 1.19 and 1.80 for 99mTc-MIBI, respectively. In another patient 99mTc-tetrofosmin and 201Tl imagings were performed. Not only the primary tumor but also the direct invasions and metastatic lesions (bone metastases) were clearly detected. The tumor-to-background ratios of planar and SPECT imagings were 2.31 and 2.78 for 99mTc-tetrofosmin and 2.45 and 3.58 for 201Tl, respectively. In 99mTc-tetrofosmin scintigraphy we acquired delayed images, and the tumor-to-background ratios of planar and SPECT delayed images were 1.20 and 1.86, the retention ratios were -1.11 and -0.92 and the retention indices were -48.1 and -33.1, respectively. Our preliminary results suggest that 99mTc-tetrofosmin is useful in detecting not only the primary tumor but also metastatic lesions from malignant thymoma.     

Correlation between 99mTc-MIBI uptake and angiogenesis in MIBI-positive breast lesions

This study was undertaken to assess the correlation between the degree of accumulation and the washout of 99m technetium methoxyisobutylisonitrile ((99m)Tc-MIBI) and angiogenesis in MIBI-positive breast lesions. Twenty-eight patients (mean age, 51+/-11 years) with 31 breast lesions who underwent scintimammography were studied. Anterior, left and right prone lateral images were obtained 20 min and 3 h after the injection of 740 MBq (99m)Tc-MIBI. All breast lesions showed increased (99m)Tc-MIBI uptake. Early and delayed tumor to background activity ratios (T/BG) and washout index (early tumor uptake-delayed tumor uptake divided by early tumor uptake) were calculated. Vascular endothelium was immunohistochemically labeled using a biotinylated monoclonal antibody directed against the factor-VIII-associated antigen using standard biotin-avidin technique. Angiogenesis was evaluated by assessing the vascular surface density (VSD) and the microvessel number (NVES) within 10 randomly chosen areas. All pathological data were compared with early and delayed T/BG activity ratios and washout index of (99m)Tc-MIBI. Statistical analysis was performed using Spearman correlation test. There was no statistically significant correlation between the degree of angiogenesis and early T/BG (r = .287, P > .05 with VSD, r = .351, P > .05 with NVES), delayed T/BG (r = .277, P > .05 with VSD, r = .315, P > .05 with NVES) and the washout index (r = .268, P > .05 with VSD, r = .285, P > .05 with NVES) of (99m)Tc-MIBI in all breast lesions. There was no statistically significant correlation between the degree of angiogenesis and early T/BG (r = .235, P > .05 with VSD, r = .356, P > .05 with NVES), delayed T/BG (r = .181, P > .05 with VSD, r = .285, P > .05 with NVES) and the washout index (r = .158, P > .05 with VSD, r = .187, P > .05 with NVES) of (99m)Tc-MIBI in 24 invasive breast lesions. No statistically significant correlation was found between the degree of angiogenesis and early T/BG (r = -.036, P > .05 with VSD, r = -.107, P > .05 with NVES), delayed T/BG (r = -.500, P > .05 with VSD, r = -.429, P > .05 with NVES), but there was a high correlation between angiogenesis and the washout index (r = .893, P < .05 with VSD, r = .964, P < .05 with NVES) of (99m)Tc-MIBI in seven noninvasive breast lesions. Amount of (99m)Tc-MIBI uptake in breast lesions is dependent on several factors. Our study indicates that early and delayed (99m)Tc-MIBI uptakes in MIBI-positive breast lesions are not related to angiogenesis in both invasive and noninvasive breast lesions. But washout index of (99m)Tc-MIBI in noninvasive breast lesions is highly correlated with angiogenesis. (99m)Tc-MIBI scintigraphy does not seem to be able to indicate angiogenic property of invasive breast lesions.     

Sensitivity and specificity of planar scintimammography with 99mTc-sestamibi.

PURPOSE: The aim of our prospective study was to determine the diagnostic accuracy of planar breast imaging with 99mTc-MIBI in detecting malignant disease. MATERIAL AND METHODS: Ninety-six consecutive patients with 121 clinically- and/or mammographically-detected breast lesions underwent preoperative planar scintimammography. Ten minutes after injection of 700 MBq 99mTc-MIBI, two lateral prone and one anterior supine projections with an acquisition time of 8 minutes each were obtained. Interpretation of scintimammographic results was made blindly and any focal accumulation of MIBI in the breasts was the criterion for an abnormal scintigram. All lesions were operated on and histologically verified. RESULTS: Histologically, 86 malignant and 35 benign lesions were found in 121 breast lesions. A sensitivity of 83.7% and a specificity of 74.2% for malignancy was achieved at planar scintimammography. CONCLUSION: Scintimammography with 99mTc-MIBI is an imaging modality of modest usefulness in the investigation of breast lesions. The method has a low sensitivity in lesions smaller than 10 mm in diameter, which decreases the clinical use of the method.     

Assessment of Tc-99m sestamibi tumor tissue uptake under the influence of increased arterial oxygen saturation

The aim of this study is to investigate the potential effect of increased arterial saturation of oxygen in the magnitude of technetium-99m-hexakis-isobutyl-isonitrile (99mTc-MIBI) uptake in tumor tissue and to compare the results with those of conventional 99mTc-MIBI tumor imaging in the same patient with lung cancer. A total of 26 lung cancer patients underwent initial SPECT (I-SPECT) and after oxygen inhalation SPECT (O2-SPECT). The early (ER) and delayed ratios (DR) of O2-SPECT mean+/-S.D. were significantly higher than those of I-SPECT mean+/-S.D. (2.07+/-0.57 vs. 1.90+/-0.48 and 2.02+/-0.45 vs. 1.83+/-0.39, respectively). There are increased rates for the relative tumor uptake of 99mTc-MIBI by 9% for ER and 10% for DR on the O2-SPECT compared to I-SPECT. We found that 99mTc-MIBI uptake increased significantly in the tumor tissue with O2-SPECT compared to I-SPECT. In conclusion, 99mTc-MIBI scintigraphy is one of the main methods for differentiating viable and nonviable tissue fractions in tumors. We consider that 99mTc-MIBI uptake increase after oxygen inhalation is an indicator of positive acute cellular response of the tumor tissue to the rising tissue oxygen level.     

99Tcm-MIBI scintimammography in the evaluation of breast lesions and axillary involvement: a comparison with mammography and histopathological diagnosis.

The aim of this prospective study was to determine the diagnostic value of prone lateral 99Tcm-MIBI scintimammography in the detection of primary breast cancer and axillary lymph node involvement in patients with breast lesions. We evaluated 83 palpable and 22 non-palpable lesions in 77 consecutive patients with a clinically palpable mass and/or suspicious mammographic finding. Early and late scintimammograms were performed after the intravenous injection of 740 MBq 99Tcm-MIBI. The overall sensitivity of both scintimammography and mammography in the detection of primary breast cancer was 94%. The overall specificity was 84% and 56% for scintimammography and mammography respectively. In the patients with palpable masses, the sensitivity of scintimammography was 97% and the specificity was 84%; in those with non-palpable masses, the sensitivity was 35% and the specificity 100%. For the detection of axillary lymph node involvement, the sensitivity and specificity of scintimammography were 68% and 93% respectively. However, conventional mammography showed 37% sensitivity and 86% specificity. In conclusion, scintimammography is an accurate and clinically valuable tool for evaluating palpable and non-palpable breast abnormalities. In addition to its high sensitivity, it improves the specificity of mammography both in the evaluation of breast masses and in the detection of axillary involvement.