Evaluation of uptake and release of technetium-99m MIBI SPECT of pulmonary and mediastinal lesions

We evaluated the uptake and release of Tc-99m MIBI in 7 benign and 30 malignant pulmonary and mediastinal lesions. Of the 37 patients, 13 underwent surgery; malignant involvement was examined in 21 mediastinal lymph nodes. Tl-201 SPECT was also performed in 10 patients. Tc-99m MIBI SPECT studies were performed on transverse SPECT images acquired 30 minutes and 3 hours after intravenous injection of 600 MBq of Tc-99m MIBI with three gamma camera detectors (GCA-9300A). Regions of interest were set in the area of abnormal uptake of Tc-99m MIBI and in an area of normal tissue in the contralateral lung. The uptake ratio of the lesion in the contralateral normal lung was obtained on the early image (early ratio; ER) as well as the delayed image (delayed ratio; DR). The benign lesions showed significantly lower ER (1.6 ± 0.3) and DR (1.4 ± 0.4) than the malignant lesions (1.9 ± 0.5 and 1.8 ± 0.5, respectively; both p < 0.05). There was no significant difference in the retention index (RI), calculated as RI = (DR ? ER)/ER × 100. The DR obtained with Tl-201 SPECT images was significantly higher than that obtained with Tc-99m MIBI SPECT (p < 0.05). For the detection of mediastinal lymph node metastases, the early images showed sensitivity, specificity, and accuracy of 85.7%, 100%, and 95.2%, respectively, for the delayed images these values were 85.7%, 92.9%, and 90.5%, respectively. These results suggest that the uptake ratio of Tc-99m MIBI is a useful index in assessing benign or malignant pulmonary and mediastinal lesions.     

Differentiation of malignant and benign solitary thyroid nodules using 30- and 120-minute tc-99m MIBI scans

Technetium-99m methoxy isobutylisonitrate (MIBI) has been found to be taken up by various tumors, including thyroid cancer. We prospectively evaluated 77 patients with cold thyroid solitary nodules on Tc-99m pertechnetate scintigraphy to evaluate the diagnostic value of Tc-99m MIBI scintigraphy. The aim of this study was to find out if thyroid nodules can be characterized on the basis of retention of MIBI and whether preoperative evaluation of malignancy is possible using this method. Single injection, dual-phase (30 and 120 minutes) thyroid scintigraphy using Tc-99m MIBI was performed in all these patients. In the following days and weeks, all patients underwent surgery. Using the 120/30-minute thyroid lesion to background radiouptake ratio (RUR), malignant and benign thyroid nodules could be separated with a sensitivity, specificity, and positive predictive value of 84.4%, 95.45%, and 93.33%, respectively. The mean RUR for malignant thyroid lesions was found to be 1.57+/-0.32, whereas for benign lesions, the ratio was significantly lower, 0.32+/-0.19. In conclusion, fine needle aspiration cytology along with the 120/30 minutes Tc-99m MIBI scintigraphy ratio appears to be useful in the preoperative assessment of solitary thyroid nodules.     

Tl-201 chloride and Tc-99m MIBI accumulation in lung adenocarcinoma in patients with and without distant metastases

PURPOSE: The relation between Tl-201 chloride accumulation by the tumor and its distant metastatic potential were evaluated in patients with lung adenocarcinoma and compared with the same parameters achieved using Tc-99m MIBI. METHODS: Fifty-six patients with primary lung adenocarcinoma were examined before therapy was begun. They were classified according to the radiologic findings and pathologic diagnosis into two groups: distant metastases and no distant metastases. All patients underwent dual-isotope imaging with Tl-201 chloride and Tc-99m MIBI. Regions of interest were placed over the tumor uptake (T) and contralateral normal lung tissue (N) areas on one transverse view with clearly defined lesions, and the T:N ratio and retention index were calculated. RESULTS: The early and delayed T:N ratios and retention index using Tl-201 chloride SPECT in the distant-metastases group were significantly greater (P < 0.001 to P < 0.05) than were those in the no-distant-metastases group. There was no significant correlation between the T:N ratio and retention index and distant metastatic potential using Tc-99m MIBI SPECT. CONCLUSION: Tl-201 chloride SPECT may be more effective than Tc-99m MIBI SPECT for evaluating the distant metastatic potential of primary lung adenocarcinoma.     

Comparative study of Tc-99m MIBI and TI-201 SPECT in predicting chemotherapeutic response in non-small-cell lung cancer

PURPOSE: Tc-99m MIBI can be excluded from cytosol against its concentration gradient as a suitable transport substrate by P-glycoprotein. Tc-99m MIBI has also been shown to be more effective than TI-201 chloride for evaluating the response to chemotherapy in patients with small-cell lung cancer. The relation between Tc-99m MIBI accumulation by the tumor and its response to chemotherapy were evaluated in patients with non-small-cell lung cancer (NSCLC) and compared with the same parameters achieved using TI-201 chloride. METHODS: Thirty-eight patients with NSCLC were examined before chemotherapy was begun. They were classified according to the results of a follow-up computed tomogram into two groups: responders were patients in whom there was a > or =50% decrease and nonresponders were patients in whom there was a <50% decrease in the sum of the product of the maximum perpendicular diameters of all measurable lesions. All patients underwent dual-isotope imaging with TI-201 chloride and Tc-99m MIBI just before chemotherapy. Regions of interest were placed over the tumor uptake (T) and contralateral normal lung tissue (N) areas on one coronal view with a clearly defined lesion, and the T:N ratio and retention index were calculated. RESULTS: The delayed T:N ratio and retention index for Tc-99m MIBI in the responder group were significantly greater (P<0.05) than those in the nonresponder group. There was no significant correlation between the T:N ratio and retention index and tumor response using TI-201 chloride. CONCLUSION: Tc-99m MIBI SPECT may be more effective than TI-201 chloride SPECT for evaluating the response to chemotherapy in patients with NSCLC.     

Double-phase Tc-99m MIBI scintigraphy as a therapeutic predictor in patients with non-Hodgkin's lymphoma

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.     

99mTc-MIBI scintigraphy in musculoskeletal tumors.

The aim of this study was to assess the value of 99mTc-hexakis2-methoxyisobutylisonitrile (MIBI) scintigraphy in patients with clinical and radiologic features of primary or metastatic musculoskeletal tumors. METHODS: The scintigraphic findings for 84 patients were compared with the surgical and histologic findings. Each patient underwent three-phase bone scanning with 99mTc-methylene diphosphonate (MDP) and dynamic and static MIBI scintigraphy. The MIBI scans were evaluated by visual and quantitative analysis. The count ratio of the lesion to the adjacent or contralateral normal area (L/N) was calculated from the region of interest drawn on the MIBI scan. The Mann-Whitney test was used to determine the differences between the uptake ratios of malignant and benign lesions. RESULTS: Although increased MDP uptake was not specific for bone malignancy, a significant difference was found between benign tumors (L/N = 1.22 +/- 0.43) and malignant tumors (L/N = 2.25 +/- 1.03) on MIBI scans. Sensitivity and specificity were 81% and 87%, respectively. Forty-six of 53 proven benign lesions did not show significant MIBI uptake. The negative predictive value was 88%. In all seven sites of pathologic fracture, significant uptake was seen. However, three malignant lesions were not detected by MIBI scintigraphy, whereas seven benign lesions showed false-positive results. CONCLUSION: The major diagnostic worth of MIBI scintigraphy is its high negative predictive value. Although not capable of replacing tissue biopsy as a definitive diagnostic modality for musculoskeletal neoplasms, MIBI scintigraphy does appear to have a role in better preoperative assessment and in distinguishing between pathologic and simple fractures.     

Tc-99m MIBI SPECT in prediction of prognosis in patients with small cell lung cancer

PURPOSE: The purpose of this study was to evaluate whether the degree of technetium-99m methoxyisobutylisonitrile (MIBI) uptake and its retention in delayed imaging in small cell lung cancer (SCLC) was correlated with the response to multiagent chemotherapy and to investigate if there was a relationship between the survival time of patients with SCLC and Tc-99m MIBI SPECT tumor uptake parameters at the time of diagnosis. METHODS: Between 1998 and by December 2004, 40 patients with SCLC were studied with Tc-99m MIBI SPECT at the time of diagnosis. The patients were classified by a follow-up CT as good responders (complete or partial remission) and poor responders (stable disease or progressive disease). Following i.v. administration of 740 MBq Tc-99m MIBI, SPECT imaging at 30 minutes (early) and 2 hours (delayed) was performed. Regions of interests were placed over the tumors and contralateral normal lung tissue on one transverse section. The uptake ratio of the lesion to that in the contralateral normal lung was obtained from early images (early ratio; ER) as well as delayed images (delayed ratio; DR). The retention index (RI%) was measured as: RI% = [(DR-ER)/ER] x 100. Tc-99m MIBI tumor uptake parameters were compared with chemotherapeutic response and survival time. RESULTS: Of 40 patients, 29 patients were good responders (72.5%) and 11 patients were poor responders (27.5%). RI% of Tc-99m MIBI SPECT in the group of good response was significantly higher than in that with poor response (p < 0.05). On the other hand, there was no significant difference between the two groups with respect to ER or DR values. Four of 40 patients were still alive with disease (10%). The patient survival time varied from 1 to 70 months (mean survival time = 12.9 +/- 13.4 months). There was no significant difference between the survival time of patients with respect to ER or DR of Tc-99m MIBI SPECT imaging. When median RI% was accepted as a cut-off value (-3.85%), patients with higher RI% values had a longer survival time (12 months) when compared with those with low RI% (8 months), p < 0.05. CONCLUSION: Our results suggest that Tc-99m MIBI SPECT could accurately predict the chemotherapy response in patients with SCLC. RI% of Tc-99m MIBI SPECT is recommended to differentiate patients with a poor response to chemotherapy and good responders, and RI% of Tc-99m MIBI SPECT appears as the only parameter that may be useful in predicting the survival of patients with SCLC.     

99Tcm-PPM及99Tcm-MIBI肺显像诊断原发性肺癌

目的 探讨99Tcm－培普利欧霉素（PPM）及99Tcm-甲氧基异丁基异腈（MIBI）肺显像诊断原发性肺癌的临床价值。方法 对28例临床诊断肺肿瘤患者进行99Tcm-PPM ey 99T0-MIBI肺肿瘤显像并进行比较。结果 肺癌与良性病变对99T -PPMey 99T-MIBI观的摄取差异有显著性（P＜0．01）,以肺癌晚期显像摄取比值（T／NT,X－S）作为判断良恶性阈值,99Tcm-PPM及99Tcm-MIBI对肺癌诊断的灵敏度,准确性分别为90％,89．3％,和80％,82．1％,两者结合显像阳性率为95％,病灶对放射性药物的摄取与肿瘤大小无明显相关（P＞0．05）,结论 99Tcm-PPM ey 99T-MIBI肺显像对肺癌的诊断,鉴别诊断有一定的临床价值。两者联合应用可提高肺癌的阳性检出率,单独使用99Tcm-PPM优于99Tcm-MIBI。     

Tc-99m MIBI SPECT is useful for noninvasively predicting the presence of MDR1 gene-encoded P-glycoprotein in patients with hepatocellular carcinoma.

PURPOSE: Resistance to chemotherapeutic drugs continues to be one of the major unsolved problems in the treatment of cancer. Multidrug resistance is defined as the ability of cells exposed to a single drug to develop resistance to a broad range of structurally and functionally unrelated drugs as a result of enhanced outward transport of drugs mediated by P-glycoprotein that is encoded by multidrug resistance genes. Recent evidence has shown that Tc-99m MIBI is a suitable transport substrate for P-glycoprotein. A potential advantage of Tc-99m MIBI SPECT is its superiority to diagnose noninvasively the presence of P-glycoprotein overexpression in vivo. In this study, the authors determined the association of enhanced MIBI efflux in Tc-99m MIBI SPECT with overexpression of P-glycoprotein in hepatocellular carcinoma. MATERIALS AND METHODS: Thirty-five patients with hepatocellular carcinoma were enrolled in the study. Tc-99m MIBI SPECT was performed 10 minutes after intravenous injection of 20 mCi Tc-99m MIBI. All patients had liver biopsy or surgery within 1 week of MIBI imaging. Immunohistochemical study of the biopsy or resected hepatocellular carcinoma specimens was performed using the avidin-biotin-peroxidase technique with monoclonal antibody JSB-1 directed against P-glycoprotein. RESULTS: On Tc-99m MIBI SPECT, 30 of 35 (85.7%) patients with hepatocellular carcinoma had no Tc-99m MIBI uptake in tumor lesions, whereas five patients with hepatocellular carcinoma had Tc-99m MIBI uptake in tumor lesions. P-glycoprotein expression was observed in tumor tissues of all the patients without Tc-99m MIBI uptake, whereas among the five patients with Tc-99m MIBI uptake, no P-glycoprotein expression was seen in tumor lesions (P < 0.015). CONCLUSION: Tc-99m MIBI SPECT is useful for noninvasively predicting the presence of MDR1 gene-encoded P-glycoprotein in patients with hepatocellular carcinoma.     

Accumulation of Tc-99m MIBI in breast lymphoma: Comparison with Ga-67 citrate

We report 2 cases of malignant lymphoma of the breast which were clearly shown on total body imaging as well as on SPECT with Ga-67 and Tc-99m MIBI. Tumor accumulation of Ga-67 was seen in all cases including a recurrent tumor. Ga-67 scintigraphy is useful for follow up in detecting relapse, as well as in predicting responses to therapy. Tc-99m MIBI was found to accumulate in the malignant lymphoma of the breast, and especially SPECT images of breast lesions provided better contrast than planar images, and Tc-99m MIBI SPECT could diagnose localization of the tumor because there was no uptake by the breast. But the Tc-99m MIBI accumulation of the tumor was lower than Ga-67.     

Tc-99m MIBI uptake and its relation to the proliferative potential of brain tumors

PURPOSE: Many studies have shown that the S-phase fraction is a reflection of the proliferation potential of tumors, and DNA aneuploidy is more common in malignant tumors. In this preliminary study, the authors assessed the Tc-99m MIBI uptake of brain tumors and its relation to tumor grade and DNA content of the tumor cells. METHODS: Ten patients (eight male, two female; mean age, 53.2 +/- 6.11 years) with untreated brain tumors were included in the study. SPECT imaging was performed 20 minutes after injection of 740 MBq (20 mCi) Tc-99m MIBI. A single detector camera with a low-energy high-resolution collimator was used for image acquisition. A region of interest was drawn in the tumor area under magnetic resonance guidance. A Tc-99m MIBI uptake index was computed as the mean tumor-to-background ratio. Flow cytometric analysis of fresh tumor tissue specimens was performed immediately. The percentages of cells in the G0/G1, S, and G2/M phases were determined for each patient. RESULTS: DNA aneuploidy was found in 4 (49%) patients, whereas diploidy was found in 6 (60%) patients. There was a significant positive correlation between the Tc-99m MIBI uptake and the percentage of the S-phase fraction of the cell cycle ( = 0.000, r = 0.95). The Tc-99m MIBI index was significantly greater in aneuploid tumors than in diploid tumors ( < 0.01). CONCLUSIONS: High-grade brain tumors have increased Tc-99m MIBI uptake compared with that of low-grade tumors. Tc-99m MIBI uptake is correlated with the percentage of the S-phase fraction of the cell and the aneuploidy level of the brain tumor. This preliminary report suggests that Tc-99m MIBI imaging may be useful in the evaluation of the biologic characteristics of brain tumors.     

Technetium-99m MIBI single photon emission computed tomography as an indicator of prognosis for patients with lung cancer —Preliminaly report—

PURPOSE: We performed technetium-99m hexakis-2-methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) in 23 patients with primary lung cancer between July 1993 and March 1996. We evaluated the relationships among the uptake ratio, retention index and the prognosis after radiation therapy and/or chemotherapy. MATERIALS AND METHODS: Tc-99m MIBI SPECT was performed at 30 minutes and at 3 hours after intravenous injection of 600 MBq of Tc-99m MIBI with three gamma camera detectors (GCA-9300A/HG) on transverse SPECT images. Regions of interest were set in the area of abnormal uptake of Tc-99m MIBI and in the contralateral normal lung. The ratio of uptake in the lesion to that in the contralateral normal lung was obtained on early images (early ratio; ER) as well as delayed images (delayed ratio: DR). The retention index (RI) was calculated as follows: RI = (DR - ER)/ER x 100. The ratio was compared with survival time and prognostic factors. RESULTS: There was no correlation between ER and DR. The patients with high RI survived longer than those with low RI (median survival, 19.4 months vs. 9.4 months; p = 0.0104 by the Mantel-Cox test). CONCLUSION: These results suggest that RI is the most useful among Tc-99m MIBI indices of primary lung cancer in predicting prognosis.     

The comparison of dual phase Tc-99m MIBI and Tc-99m MDP scintimammography in the evaluation of breast masses: Preliminary report

The aim of this prospective study was to determine the diagnostic value of Tc-99m MDP scintimammography (SMG) for the detection of breast cancer in patients with breast masses and to compare the results with Tc-99m MIBI scintimammography. Twenty patients, categorized as suspicious, positive or benign for breast cancer according to the mammographic findings were included in the study. Dual phase Tc-99m MIBI and Tc-99m MDP SMG were performed in the prone lateral position within 5 days of each other. Although early and late Tc-99m MIBI SMG showed equal (90.4%) sensitivity, the specificity of late Tc-99m MIBI (87.5%) was found superior to early (62.5%) imaging. The overall sensitivity and specificity of early Tc-99m MDP SMG were 71.4% and 62.5%, respectively. Although late Tc-99m MDP imaging showed 100% specificity, its sensitivity was only 23.8%. In the patients with palpable masses, both early Tc-99m MDP and Tc-99m MIBI showed equal sensitivity (100%), but the sensitivity of early Tc-99m MIBI (37.5%) was found slightly higher than Tc-99m MDP (25.0%) for nonpalpable breast lesions. The sensitivity of Tc-99m MIBI and Tc-99m MDP SMG in detecting metastatic axillary involvement was 66.6% and 50%, respectively. High sensitivity and specificity together with its low cost, easy availability and the possibility of detecting bone metastases seems to make Tc-99m MDP a contributive agent in the evaluation of breast lesions as an alternative to Tc-99m MIBI.     

99mTc-tetrofosmin scintigraphy in musculoskeletal tumours: the relationship between P-glycoprotein expression and tetrofosmin uptake in malignant lesions

The aims of this study were to assess the role of (99m)Tc-tetrofosmin scintigraphy in the diagnosis of malignant vs. benign musculoskeletal tumours and to determine the relationship between P-glycoprotein expression and tetrofosmin uptake in malignant lesions. Forty-six patients (32 malignant, 14 benign) with various musculoskeletal lesions were studied. Each patient underwent (99m)Tc-methylene diphosphonate three-phase bone scanning initially. At least 2 days later, dynamic and static (99m)Tc-tetrofosmin scans were obtained. The tetrofosmin scans were evaluated by visual and quantitative analysis. The count ratio of the lesion to the contralateral normal area (uptake ratio, UR) was calculated from the region of interest drawn on the tetrofosmin scan. The lesions were then resected by open biopsy to obtain a histopathological diagnosis. P-glycoprotein levels were determined immunohistochemically in 22 of 32 malignant lesions. A significant difference between the mean UR values of benign and malignant lesions was found (1.36 +/- 0.47 vs. 3.35 +/- 2.08, P = 0.000). Visual analysis showed an accuracy of 85%, and the accuracy of the quantitative analysis was 87% with the threshold level of UR as 1.76. When perfusion findings were added to the evaluation criteria, the accuracies of visual and quantitative analysis were increased to 87% and 89%, respectively. The relationship between the levels of P-glycoprotein and the UR values of tetrofosmin was not statistically significant (r = -0.235, P = 0.2). In addition, the mean UR value of the patients with P-glycoprotein expression was not statistically different from that of the patients without P-glycoprotein expression (3.01 +/- 1.48 vs. 4.27 +/- 2.90, P = 0.297). In conclusion, visually significant tetrofosmin uptake and increased perfusion in a musculoskeletal lesion strongly suggest that the lesion is malignant (positive predictive value, 96%). P-glycoprotein expression was not found to be a major factor interfering with 30 min tetrofosmin uptake in a malignant musculoskeletal lesion. However, the relatively high false-negative rate among negative results (28%) limits the value of (99m)Tc-tetrofosmin scintigraphy as a single diagnostic tool in differentiating between benign and malignant musculoskeletal tumours.     

A new semiquantitative method for comparing brain tumor uptake of Tc-99m sestamibi and TI-201.

PURPOSE: We describe a new method for measuring brain tumor uptake of TI-201 and Tc-99m sestamibi (MIBI) that permits the semiquantitative comparison of tracer uptake to yield comparable "tumor bulk" ratios. We tested this method in patients treated recently and remotely with chemotherapy to determine if this method could identify differences between these two patient groups. METHODS: Eleven patients with high-grade astrocytoma underwent TI-201 and Tc-99m MIBI SPECT. Each patient received 5 mCi TI-201 intravenously followed by SPECT using a dual-head gamma camera. This was immediately followed by an intravenous injection of 20 mCi Tc-99m MIBI and repeated SPECT. Four patients had recent therapy (from 1 day to 6 weeks before SPECT) and seven had remote treatment (>1 year before SPECT). Regions of interest were outlined in the tumor area using a computer-automated program to include all counts above background activity. Tumor activity counts were obtained from this region of interest. The tumor region of interest was mirrored to the contralateral uninvolved cerebral hemisphere to obtain background control count activity. A hypothetical volume of the number of pixels with background count activity necessary to constitute the tumor count activity (tumor bulk) was calculated using the ratio of total tumor counts (Ct), subtracting background (Cb), and dividing by the average counts per pixel in the control region (Cab). This was multiplied by the number of pixels (P), the pixel volume (Vp), and summed over all sections (i) involved with tumor. This method yields the equation tumor bulk = RESULTS: The mean Tc-99m MIBI to TI-201 tumor bulk ratio was 1.03 (range, 0.81 to 1.12) in four patients who had recently received chemotherapy. The mean Tc-99m MIBI to TI-201 tumor bulk ratio was 1.55 (range, 1.46 to 1.64) in seven patients who had remote therapy. The difference in the Tc-99m MIBI to TI-201 tumor bulk ratio between the two groups was significant (P = 0.0001). Patients who received recent chemotherapy had relatively lower Tc-99m MIBI uptake compared with TI-201. In remotely treated patients, uptake of the Tc-99m MIBI was greater compared with TI-201. CONCLUSION: This method allows semiquantitative comparison of different tracer uptake values independent of tracer dose and reduces the variability in drawing a region of interest when measuring tumor uptake. Among the patients studied, those who had recent chemotherapy showed a low Tc-99m MIBI to TI-201 ratio. This method of measuring "tumor bulk" can provide a useful index of viable tumor size in evaluating early tumor response and during ongoing chemotherapy.     

吸氧99Tcm-MIBI SPECT与定位CT结合对肺部病灶的鉴别诊断价值

目的 探讨吸氧99Tcm-甲氧基异丁基异腈（MIBI）SPECT与定位CT结合对肺部病灶的鉴别诊断价值,为肺部病灶的良恶性鉴别建立一种高性价比方法。方法对2008年9月至2009年3月47例可疑恶性肺部病灶患者进行前瞻性研究,对疑似炎性反应病例短期应用抗生素。所有受检者于注射99TcmMIBI前开始经鼻腔导管吸氧,注射后10min进行SPECT与CT定位融合显像,2h后进行延迟显像。对良、恶性肺部病灶（T）与对侧相应肺组织（N）的摄取比值（早期：EUR,延迟：DUR）比较应用独立样本t检验,并对EUR和DUR的诊断效率进行受试者工作特征（ROC）曲线分析。结果47例患者（32例原发性肺癌,4例肺转移,11例良性病变）共51个肺部病灶,恶性病灶39个,良性病灶12个。99TcmMIBISPECT与定位CT融合显像诊断肺部良恶性病灶的灵敏度、特异性、准确性、阳性预测值和阴性预测值分别为94．9％（37／39）、83．3％（10／12）、92．2％（47／51）、94．9％（37／39）和83．3％（10／12）。恶性病灶EUR为2．95±1．16[95％可信区间（CI）：2．57～3．32）],良性病灶EUR为1．43±0．33（95％CI：1．22～1．64）,两者差异有统计学意义（t=-4．44,P〈0．01）;恶性病灶DUR为3．19±1．74（95％CI：2．62—3．75）,良性病灶DUR为1．60±0．32（95％CI：1．39—1．81）,两者差异有统计学意义（t=-3．12,P〈0．01）。半定量ROC分析显示：以EUR≥1．625为诊断肺部恶性病灶的界值,灵敏度97．4％（38／39）,特异性83．3％（10／12）;以DUR≥1．75为诊断肺部恶性病灶的界值,灵敏度94．9％（37／39）,特异性83．3％（10／12）。结论吸氧99TcmMIBISPECT与定位CT结合显像对肺部病灶的良恶性鉴别具有较高的临床价值。     

Gated TI-201 myocardial perfusion SPECT: application of energy window optimization.

PURPOSE: TI-201 scintigraphy is plagued with poor image quality because of the low-energy photons of TI-201 decay. Traditionally, a narrow 20% window centered on 71-72 keV has been used to improve sensitivity. Recent studies indicate that better imaging may be possible by optimizing the energy window to 34% centered on 77 keV. In this study, energy window optimization (EWO) was applied to gated TI-201 myocardial perfusion SPECT, and myocardial functional parameters were compared for gated TI-201 SPECT and gated Tc-99m sestamibi (Tc-99m MIBI) SPECT. METHODS: Count statistics for standard and optimal TI-201 myocardial scintigraphy were noted in 25 patients by assessing the total counts in a mid-ventricular slice of a rest-gated TI-201 myocardial SPECT study. The feasibility of performing functional studies with the application of EWO to TI-201 was assessed using the count statistics of a mid-ventricular slice of an optimized gated TI-201 SPECT study and a gated Tc-99m MIBI SPECT study. The functional parameters (ejection fraction, wall motion, and thickening) of TI-201 with EWO and Tc-99m MIBI were compared in 60 patients who underwent rest-gated TI-201 SPECT followed by poststress gated Tc-99m MIBI SPECT. The left ventricular ejection fraction was calculated using commercially available software, whereas wall thickness and motion were assessed by the consensus of two readers. RESULTS: The application of EWO increased available counts by more than 25%. It also resulted in sufficient counts being available to perform gated TI-201 SPECT without increasing acquisition times or the dose of TI-201. The average ejection fraction was 60.4% for gated TI-201 SPECT and 59.6% for gated Tc-99m MIBI SPECT (not significantly different). Overall, the image quality was rated excellent in 12% for TI-201 and Tc-99m MIBI and good in 50% and 62%, respectively, and poor in 38% and 26%, respectively. CONCLUSION: The application of EWO to TI-201 SPECT allows myocardial functional parameters to be assessed without having to increase the acquisition times or the administered dose of TI-201.     

Accuracy of left ventricular ejection fraction determined by gated myocardial perfusion SPECT with Tl-201 and Tc-99m sestamibi: Comparison with first-pass radionuclide angiography

BACKGROUND: We compared estimates of left ventricular ejection fraction (LVEF) assessed by gated single photon emission computed tomography (SPECT), using both technetium-99m sestamibi and thallium-201, with those obtained by first-pass radionuclide angiography (FPRNA) in patients with a broad spectrum of LVEF and perfusion abnormalities. METHODS: Sixty-three patients were randomly selected to undergo a dual isotope gated SPECT study (rest Tl-201 followed by adenosine Tc-99m sestamibi scintigraphy). Studies were processed by use of the Cedars quantitative gated SPECT software. FPRNA was acquired during an intravenous bolus injection of Tc-99m sestamibi and processed with a commercially available software. RESULTS: The estimates of LVEF were similar (P = NS) with Tl-201 gated SPECT (54% +/- 15%), Tc-99m gated SPECT (54% +/- 16%), and FPRNA (54% +/- 12%). There was an excellent correlation between Tc-99m and Tl-201 gated SPECT (Pearson's r = 0.92, P < .0001). There were also good linear correlations between Tc-99m sestamibi gated SPECT and FPRNA (Pearson's r = 0.85, P < .0001), as well as between Tl-201 gated SPECT and FPRNA (Pearson's r = 0.84, P < .0001). In the 16 patients with LVEF < 50%, Tc-99m sestamibi gated SPECT and FPRNA (Pearson's r = 0.84, P < .0001) and Tl-201 gated SPECT and FPRNA (Pearson's r = 0.92, P < .0001) correlated well. CONCLUSION: LVEF can be accurately assessed by gated SPECT with either Tc-99m sestamibi or Tl-201 in properly selected patients with normal or depressed left ventricular function.     

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.     

The diagnosis of coronary artery disease in hypertensive patients with chest pain and complete left bundle branch block: utility of adenosine Tc-99m tetrofosmin SPECT

PURPOSE: Hypertensive patients with complete left bundle branch block who experience chest pain present special problems in the radionuclide diagnosis of coronary artery disease (CAD). The aim of this study was to assess the utility of Tc-99m tetrofosmin SPECT for the diagnosis of CAD in 35 hypertensive patients with left bundle branch block hospitalized for chest pain. MATERIALS AND METHODS: Images were analyzed semiquantitatively for the presence of both fixed or reversible perfusion defects (method A) or only reversible defects (method B) in the distribution of the left anterior descending artery (LAD) territory. Perfusion defects observed in the territory of any other coronary artery were always considered. Thirty-five patients without infarction underwent adenosine Tc-99m tetrofosmin SPECT, transthoracic echocardiography, and coronary angiography. RESULTS: The mean left ventricular ejection fraction was calculated as 39.9% +/- 11.6%, and the prevalence of CAD was 29%. The sensitivity of SPECT was identical for the two methods at 89%. The specificity increased 19% with method A and 54% with method B. The positive predictive value remained unsatisfactorily low with both methods (27% for method A and 40% for method B), and the negative predictive value improved from 83% with method A to 93% with method B. CONCLUSIONS: Only reversible perfusion defects in the LAD territory should be considered significant for CAD, and these patients should undergo coronary angiography. Reversible or fixed perfusion defects in the left circumflex and right coronary artery territories should be evaluated according to other clinical parameters (global left ventricular ejection fraction, extension of perfusion defects). The highly negative predictive value of adenosine SPECT could help in the exclusion of CAD.