Scintimammography with technetium-99m methoxyisobutylisonitrile: comparison with mammography and magnetic resonance imaging

The aim of the study was to compare the diagnostic accuracy of scintimammography with technetium-99m methoxyisobutylisonitrile (MIBI; SMM) in the detection of primary breast cancer with that of mammography (MM) and magnetic resonance imaging (MRI). Fifty-six patients with suspected lesions detected by palpation or MM were included in the study. Within the 4 weeks preceding excisional biopsy, MM and MRI were performed in all patients. Between 5 and 10 min after the injection of 740 MBq^99mTc-MIBI, SMM in the prone position was performed. In the total group of 56 patients, 43 lesions were palpable, while 13 were non-palpable but were detected by MM. Breast cancer was confirmed by histopathology in 27 of the patients (22 palpable and 5 non-palpable carcinomas). The tumour size ranged from 6 to 80 mm in diameter. For non-palpable lesions, the sensitivity of SMM, MM and MRI was 60%, 60% and 100%, respectively, while the specificity was 75%, 25% and 50%, respectively. For palpable breast lesions, all methods showed high sensitivity (SMM 91%, MM 95%, MRI 91%) but SMM demonstrated significantly higher specificity (SMM 62%, MM 10%, MRI 15%). In two mammographically negative tumours (dense tissue), SMM showed a positive result. In comparison to MRI, one additional carcinoma could be diagnosed by SMM. It may be concluded that for palpable breast lesions, the diagnostic accuracy of SMM is superior to that of MM and MRI. Through the complementary use of SMM it is possible to increase the sensitivity for the detection of breast cancer and multicentric disease. In patients in whom the status of a palpable breast mass remains unclear, SMM may help to reduce the amount of unnecessary biopsies.     

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.     

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.     

Three patients with bilateral breast tumors examined by technetium-99m-sestamibi scintimammography

We presented three patients with bilateral breast tumors (one with breast cancers, one with breast cancer and fibroadenoma, and one with fibroadenomas) examined by^99mTc-hexakis 2-methoxy-isobutylisonitrile (MIBI) scintimammography. In all cases^99mTc-MIBI uptake was recognized only in the breast cancers.^99mTc-MIBI scintimammography was useful in evaluating bilateral breast tumors since preoperative diagnosis is valuable in determining correct surgical treatment.     

Preoperative evaluation of the chemosensitivity of breast cancer by means of double phase99mTc-MIBI scintimammography

The chemosensitivity of breast cancer is important for its management, but it is difficult to evaluate preoperatively. Tc-99m hexakis-2-methoxyisobutylisonitrile (MIBI) scintimammography has been reported to indicate the expression of P-glycoprotein, which is one factor concerned with multidrug resistance. We developed a chemosensitivity assay by using surgical specimens to investigate whether^99mTc-MIBI scintimammography findings before the operation are related to chemosensitivity according to our assay. Fifteen patients with primary breast cancer were enrolled into the study. Early and delayed images were obtained at 10 and 120 minutes after intravenous injection of^99mTc-MIBI, respectively. Regions of interest were placed on the tumors and the contralateral healthy breasts in each patient to estimate^99mTc-MIBI uptake in the tumor, and retention indices were then calculated to assess the washout of^99mTc-MIBI. Chemosensitivity assay was performed by incubating surgical specimens with anticancer agents such as doxorubicin, epirubicin, pinorubicin, mitomycin C, cisplatin and 5-fluorouracil.^99mTc-MIBI washout on scintimammography was successfully related to inhibition ratios on chemosensitivity tests when compared with^99mTc-MIBI uptake by the tumor. In particular, high correlation coefficients were obtained between the retention index of^99mTc-MIBI and the inhibition ratios of doxorubicin (r = 0.75), epirubicin (r = 0.60) and pinorubicin (r = 0.62), but poor correlation was found for mitomycin C (r = 0.44) and cisplatin (r = 0.31). Our results indicate that the retention index of^99mTc-MIBI is closely correlated to chemosensitivity to anthracyclines, suggesting that double-phase scintimammography allows preoperative prediction of chemosensitivity of breast cancer.     

The use of technetium-99m methoxyisobutylisonitrile breast scintigraphy to evaluate palpable breast masses

Thirty-eight female patients (age range: 31–79 years) with breast masses underwent technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI) breast scintigraphy in order to assess the value of this technique in the detection of breast carcinomas and in their differentiation from benign breast masses. The results showed that 27 of the 32 cases of breast carcinoma were detected by ^99mTc-MIBI breast scintigraphy. In contrast, none of the six benign lesions could be detected by this method. The diagnostic sensitivity, specificity and accuracy were 84%, 100% and 87%, respectively, in the differentiation of malignant and benign breast masses. In conclusion, we consider ^99mTc-MIBI breast scintigraphy is useful in distinguishing malignancies from benign breast masses. Correspondence to: C.H. Kao     

High-resolution scintimammography improves the accuracy of technetium-99m methoxyisobutylisonitrile scintimammography: use of a new dedicated gamma camera

. The main disadvantage of technetium-99m methoxyisobutylisonitrile (MIBI) prone scintimammography is its limited sensitivity for T1a and T1b cancers with a size of less than 1 cm. We have developed a high-resolution scintimammographic technique using a gamma camera based on a new concept, namely a position-sensitive photo-multiplier tube. The field of view of this camera, previously known as the SPEM (single photon emission mammography) camera, was 10 cm diameter. Scintimammographic images were acquired in the axial view; each breast was compressed to a thickness of 3–6 cm, modal class 4 cm. When the compressed breast was larger than the field of view, more than one study was performed in order to image the entire gland. Fifty-three patients were studied with high-resolution-scintimammography (HRSM) and Anger camera prone scintimammography (ACPSM). HRSM was performed 70 min after i.v. administration of 740 Mbq of ^99mTc-MIBI; ACPSM images were acquired 10 and 60 min following the injection. Early 10-min ACPSM images were only evaluated for routine diagnostic purposes, while comparison was carried out between the 60-min ACPSM and 70-min HRSM images. At fine-needle aspiration (FNA) and/or open biopsy, 31 patients showed cancer: 15 T1c, 11 T1b and 5 T1a. In T1a-T1b cancers, the sensitivity of scintimammography was 50% with ACPSM and 81.2% with HRSM (P<0.01). Specificity was 86% with both techniques. HRSM is a promising new technique that improves the sensitivity of ^99mTc-MIBI scintimammography in tumours sized less than 1 cm without apparently reducing its specificity. We are now working on a larger field-of-view camera. Received 10 February and in revised form 28 April 1999     

^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。     

99mTc-tetrofosmin SPET in the detection of both primary breast cancer and axillary lymph node metastasis

The aim of this study was to evaluate the usefulness of ^99mTc-tetrofosmin single-photon emission tomography (SPET) in the detection of both primary breast cancer and axillary lymph node metastasis. We studied 192 consecutive patients in whom primary breast cancer was suspected on the basis of mammography and/or physical examination. After intravenous injection of 740 MBq ^99mTc-tetrofosmin, both planar and SPET scintimammography was performed in all patients using a rectangular dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators. In 175 patients with breast cancer at histology, the per-lesion overall sensitivity of SPET and planar imaging for the detection of breast cancer was 95.8% and 75.9% (P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 96.5% and 79.5% in palpable (P<0.0005) and 90% and 45% in non-palpable lesions (P<0.01). With regard to lesion size, the sensitivity of SPET and planar imaging was, respectively, 90.5% and 45.2% in lesions ⢪ mm (P<0.0005), 95.3% and 81.4% in lesions of 11-20 mm (P<0.005), 100% and 84.6% in lesions of 21-30 mm (P<0.05) and 100% and 95.8% in lesions >30 mm (P>0.05). In the remaining 17 patients with benign mammary lesions at histology, per-lesion overall specificity of SPET and planar imaging was 76.2% and 85.7% (P>0.05), respectively. Neither SPET nor planar imaging showed false-positive results in non-palpable lesions or in those ⢪ mm. In 173 breast cancer patients submitted to axillary lymph node dissection (ALND), per-axilla overall sensitivity of SPET and planar imaging in the detection of axillary lymph node metastasis was 93% and 52.3% (P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 100% and 82.6% in palpable nodes (P>0.05), 90.5% and 41.3% in non-palpable nodes (P<0.0005), 92.8% and 35.7% in the presence of Г nodes (P<0.0005) and 93.2% and 68.2% in the presence of >3 nodes (P<0.005). The specificity of SPET and planar imaging was 91% and 100% (P<0.05), respectively. ^99mTc-tetrofosmin SPET appears to be a reliable method for the detection of both primary BC and axillary lymph node metastasis, and its diagnostic accuracy exceeds that of ^99mTc-tetrofosmin planar scintimammography. The use of SPET is particularly important in the identification of small non-palpable primary carcinomas and metastatic axillae with Г non-palpable lymph nodes. More extensive use of SPET appears warranted in the management of breast cancer patients.     

Technetium-99m sestamibi scintimammography: the influence of histopathological characteristics, lesion size and the presence of carcinoma in situ in the detection of breast carcinoma.

The limit of detection of invasive carcinoma by scintimammography appears to be >10 mm, but not uncommonly smaller invasive carcinoma is detected in the presence of pre-invasive carcinoma (carcinoma in situ). The aims of this study were to determine whether a relationship exists between the presence of carcinoma in situ and the detection of invasive carcinoma using scintimammography, and to further characterise the influence of lesion size and histopathological characteristics on the diagnostic accuracy of scintimammography for the detection of invasive breast carcinoma. One hundred and seventeen patients were studied prospectively by scintimammography, X-ray mammography and, where appropriate, breast ultrasound prior to excision biopsy of all suspicious breast masses (n=123, 93% palpable). Thirty-five of these patients had a history of previous ipsilateral breast carcinoma. Sixteen percent of biopsy specimens were benign. The remaining specimens were malignant or pre-malignant. The overall diagnostic sensitivity of scintimammography was 84% and the specificity was 80%. The overall sensitivity and specificity for X-ray mammography (n=123), including those examinations combined with breast ultrasound (n=76), were 73% and 69%, respectively. The maximum size of the measured invasive carcinoma ranged from 5 to 80 mm (median 20 mm). Although the maximum size detected for invasive carcinoma in the presence of carcinoma in situ ranged from 3 to 40 mm (median 20 mm), this difference was not statistically significant (P=1.10, t test). Seven cases of carcinoma in situ were not detected by scintimammography. The diagnostic sensitivity of scintimammography for the detection of invasive carcinoma was 98% for lesions 16-25 mm, 91% for lesions 11-25 mm, 78% for lesions >25 mm and 55% for lesions <11 mm. Scintimammography may offer increased diagnostic accuracy for the detection of breast carcinoma, thereby complementing anatomical imaging. This is particularly evident in technically difficult patients who have had previously treated breast cancer. There appears to be no difference in the diagnostic sensitivity of scintimammography for the detection of invasive carcinoma in the presence or absence of carcinoma in situ.     

(99)mTc-tetrofosmin SPET in the detection of both primary breast cancer and axillary lymph node metastasis.

The aim of this study was to evaluate the usefulness of (99m)Tc-tetrofosmin single-photon emission tomography (SPET) in the detection of both primary breast cancer and axillary lymph node metastasis. We studied 192 consecutive patients in whom primary breast cancer was suspected on the basis of mammography and/or physical examination. After intravenous injection of 740 MBq (99m)Tc-tetrofosmin, both planar and SPET scintimammography was performed in all patients using a rectangular dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators. In 175 patients with breast cancer at histology, the per-lesion overall sensitivity of SPET and planar imaging for the detection of breast cancer was 95.8% and 75.9% (P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 96.5% and 79.5% in palpable (P<0.0005) and 90% and 45% in non-palpable lesions (P<0.01). With regard to lesion size, the sensitivity of SPET and planar imaging was, respectively, 90.5% and 45.2% in lesions < or =10 mm ( P<0.0005), 95.3% and 81.4% in lesions of 11-20 mm (P<0.005), 100% and 84.6% in lesions of 21-30 mm (P<0.05) and 100% and 95.8% in lesions >30 mm (P>0.05). In the remaining 17 patients with benign mammary lesions at histology, per-lesion overall specificity of SPET and planar imaging was 76.2% and 85.7% (P>0.05), respectively. Neither SPET nor planar imaging showed false-positive results in non-palpable lesions or in those < or =10 mm. In 173 breast cancer patients submitted to axillary lymph node dissection (ALND), per-axilla overall sensitivity of SPET and planar imaging in the detection of axillary lymph node metastasis was 93% and 52.3% ( P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 100% and 82.6% in palpable nodes (P>0.05), 90.5% and 41.3% in non-palpable nodes (P<0.0005), 92.8% and 35.7% in the presence of < or =3 nodes ( P<0.0005) and 93.2% and 68.2% in the presence of >3 nodes (P<0.005). The specificity of SPET and planar imaging was 91% and 100% (P<0.05), respectively. (99m)Tc-tetrofosmin SPET appears to be a reliable method for the detection of both primary BC and axillary lymph node metastasis, and its diagnostic accuracy exceeds that of (99m)Tc-tetrofosmin planar scintimammography. The use of SPET is particularly important in the identification of small non-palpable primary carcinomas and metastatic axillae with < or =3 non-palpable lymph nodes. More extensive use of SPET appears warranted in the management of breast cancer patients.     

Optimization of X-ray mammography and technetium-99m methoxyisobutylisonitrile scintimammography in the diagnosis of non-palpable breast lesions

The purpose of this study was to evaluate the contribution of technetium-99m methoxyisobutylisonitrile (MIBI) scintimammography to the early diagnosis of breast cancer in 78 patients with non-palpable breast lesions detected by mammography. In all cases biopsy was indicated and they were classified into three groups according to the mammographic findings: high (28), intermediate (30) and low (20) mammographic probability of malignancy. Histological diagnosis confirmed 37 benign and 41 malignant lesions. In the high-probability group ^99mTc-MIBI scintimammography changed the four false-positives into true negatives at the expense of two false-negatives; in the intermediate group it changed nine of the 17 false-positives into true-negatives at the expense of one false-negative, and in the low-probability group it changed five of the 16 false-positives into true-negatives without false-negatives. Applying scintimammography to patients included in the intermediate and low-probability groups together, 14 of the 33 mammographic false-positives were changed into true-negatives with 1 false-negative; thus, 41% of the unnecessary biopsies would have been avoided. When MIBI scintimammography was applied to the low-probability group, the negative predictive value was 100% and the unnecessary biopsies would have been reduced by 31%. Received 10 November 1997 and in revised form 19 January 1998     

Technetium-99m sestamibi scintimammography: the influence of histopathological characteristics, lesion size and the presence of carcinoma in situ in the detection of breast carcinoma

The limit of detection of invasive carcinoma by scintimammography appears to be >10 mm, but not uncommonly smaller invasive carcinoma is detected in the presence of pre-invasive carcinoma (carcinoma in situ). The aims of this study were to determine whether a relationship exists between the presence of carcinoma in situ and the detection of invasive carcinoma using scintimammography, and to further characterise the influence of lesion size and histopathological characteristics on the diagnostic accuracy of scintimammography for the detection of invasive breast carcinoma. One hundred and seventeen patients were studied prospectively by scintimammography, X-ray mammography and, where appropriate, breast ultrasound prior to excision biopsy of all suspicious breast masses (n=123, 93% palpable). Thirty-five of these patients had a history of previous ipsilateral breast carcinoma. Sixteen percent of biopsy specimens were benign. The remaining specimens were malignant or pre-malignant. The overall diagnostic sensitivity of scintimammography was 84% and the specificity was 80%. The overall sensitivity and specificity for X-ray mammography (n=123), including those examinations combined with breast ultrasound (n=76), were 73% and 69%, respectively. The maximum size of the measured invasive carcinoma ranged from 5 to 80 mm (median 20 mm). Although the maximum size detected for invasive carcinoma in the presence of carcinoma in situ ranged from 3 to 40 mm (median 20 mm), this difference was not statistically significant (P=1.10, t test). Seven cases of carcinoma in situ were not detected by scintimammography. The diagnostic sensitivity of scintimammography for the detection of invasive carcinoma was 98% for lesions 16–25 mm, 91% for lesions 11–25 mm, 78% for lesions >25 mm and 55% for lesions <11 mm. Scintimammography may offer increased diagnostic accuracy for the detection of breast carcinoma, thereby complementing anatomical imaging. This is particularly evident in technically difficult patients who have had previously treated breast cancer. There appears to be no difference in the diagnostic sensitivity of scintimammography for the detection of invasive carcinoma in the presence or absence of carcinoma in situ. Received 12 April and in revised form 3 July 1999     

Comparison of fluorine-18 fluorodeoxyglucose positron emission tomography and technetium-99m methoxyisobutylisonitrile scintimammography in the detection of breast tumours

The aim of this study was to compare, in breast cancer patients, the diagnostic accuracy of positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) and scintimammography (SMM) using technetium-99m methoxyisobutylisonitrile (MIBI). A total of 20 patients (40 breasts with 22 lesions) were evaluated serially with MIBI and, on the following day, with FDG. For SMM, planar and single-photon emission tomography imaging in the prone position was performed starting at 10 min following the injection of MIBI (740 MBq). For PET, scans were acquired 45–60 min after the injection of FDG (370 MBq) and attentuation correction was performed following transmission scans. Results from SMM and PET were subsequently compared with the histopathology results. True-positive results were obtained in 12/13 primary breast cancers (mean diameter=29 mm, range 8–53 mm) with both FDG and MIBI. False-negative results were obtained in two local recurrences (diameter <9 mm) with both FDG and MIBI. In benign disease, FDG and MIBI did not localize three fibrocystic lesions, two fibroadenomas and one inflammatory lesion (true-negative), but both localized one fibroadenoma (false-positive). Collectively, the results demonstrate a sensitivity of 92%, and a specificity of 86%, for primary breast cancer regardless of whether FDG or MIBI was used. In contrast to MIBI scintigraphy, FDG PET scored the axillae correctly as either positive (metastatic disease) or negative (no axillary disease) in all 12 patients. The tumour/non-tumour ratio for MIBI was 1.97 (range 1.43–3.1). The mean standard uptake value (SUV) for FDG uptake was 2.57 (range 0.3–6.2). The diagnostic accuracy of SMM was equivalent to that of FDG PET for the detection of primary breast cancer. For the detection of in situ lymph node metastases of the axilla, FDG seems to be more sensitive than^99mTc-MIBI.     

Review of imaging techniques for the diagnosis of breast cancer: a new role of prone scintimammography using technetium-99m sestamibi

Imaging techniques currently used for the diagnosis of breast cancer are reviewed and compared. Besides mammography, magnetic resonance imaging, positron emission tomography, and thallium-201 scintimammography, a new role of technetium-99m sestamibi scintimammography is discussed. It is concluded that while mammography remains the procedure of choice in screening asymptomatic women for breast cancer, other imaging methods play an important role in detecting malignancies in symptomatic patients.^99mTc-sestamibi scintimammography has high sensitivity and improves the specificity of conventional mammography for the detection of breast cancer; with this technique, prone imaging is preferable to supine imaging.^99mTc-sestamibi scintimammography thus deserves further study as a screening technique.     

Technetium-99m-sestamibi scintimammography of benign and malignant phyllodes tumors

We presented two cases of phyllodes tumor of the breast examined by^99mTc-sestamibi (MIBI) two-phase scintimammography. In the case with malignant phyllodes tumor,^99mTc-MIBI accumulation was recognized on both early and delayed images. In the case with benign phyllodes tumor, however,^99mTc-MIBI accumulation was recognized on only the early image.^99mTc-MIBI delayed imaging may have the potential to distinguish between benign and malignant phyllodes tumors.     

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.     

Can scintimammography with (99m)Tc-MIBI identify multifocal and multicentric primary breast cancer?

Scintimammography with (99m)Tc-MIBI has been shown to be an effective adjunct to imaging of the breast with mammography. Uptake of (99m)Tc-MIBI is particularly high in sites of non-calcified cancer and ductal carcinoma in situ (DCIS), and as a consequence it may be possible to use this method of imaging in identifying multifocal or multicentric disease. The aim of this study was to evaluate the efficacy of preoperative scintimammography in the detection of multifocal and multicentric breast cancer and compare these results with mammography. A retrospective review was performed of 353 women imaged with (99m)Tc-MIBI as part of the clinical assessment of their suspected primary breast cancer. The results of the scintimammography and mammography were then compared with the final pathological diagnosis obtained after mastectomy in all patients. Histopathological assessments of breast tissue from mastectomy confirmed 40 women (12%) had multifocal (34) or multicentric (six) breast cancer. Scintimammography correctly identified 39 of these cancers and the multifocal or multicentric character of the cancer was identified in 22 (52%) of these patients. Anatomical imaging performed in all 40 patients including 25 with mammography alone, mammography and ultrasound in 11 cases and ultrasound alone in four patients. Anatomical imaging identified cancer to be present in 28 patients (70%) and the combination of mammography and ultrasound identified correctly that the cancer was multifocal or multicentric in eight patients (22%). In this study scintimammography was able to identify more cases of multifocal and multicentric cancer than mammography and/or ultrasound. In patients where pre-operative identification of multicentric or multifocal disease can alter treatment scintimammography may be a useful investigative tool.     

Complementary use of scintimammography with 99m-Tc-MIBI to triple diagnostic procedure in palpable and non-palpable breast lesions

Purpose: 
The aim of this study was to determine the clinical value of scintimammography with ⁹⁹m-Tc-MIBI (Sc) as a complementary method to the triple diagnostic procedure in the diagnosis of breast lesions. Material and Methods: 
Ninety-six consecutive patients with 65 palpable and 54 non-palpable breast lesions were included in a prospective study. All lesions were evaluated by clinical examination, mammography and fine-needle-aspiration cytology (FNAC), called triple diagnostic procedure (TD). Prone planar scintimammography with ⁹⁹m-Tc-MIBI was performed in all patients. Five groups were defined for diagnosis: 1 = normal; 2 = benign; 3 = probably benign; 4 = highly suspect of malignancy; and 5 = malignant. In the calculations, groups 1-3 were considered benign, and 4-5 malignant. All lesions were excised and examined histologically. The additional value of Sc + TD procedure was studied separately for palpable and non-palpable lesions. Results: 
Histologically, 83 malignant and 36 benign lesions were found in the 119 breast lesions. Sensitivity for malignancy in palpable lesions of TD alone and of the combination TD + Sc were 95.6% and 100%, respectively. Sensitivity for malignancy in non-palpable lesions of TD and TD + Sc was 89.1% and 97.2%, respectively. Conclusion: 
Adding scintimammography to the triple diagnostic procedure increased the sensitivity for the detection of both palpable and non-palpable breast cancers, but decreased the specificity.     

A head-to-head comparison between technetium-99m-tetrofosmin and technetium-99m-MIBI scintigraphy to evaluate suspicious breast lesions

The aim of this study was to assess the diagnostic value of technetium-99m-tetrofosmin and technetium-99m-MIBI in a head-to-head comparison. Both radiopharmaceuticals are routinely used for detecting breast cancer. In a prospective, open, diagnostic trial, the two radiopharmaceuticals were administered randomly on different days to the same 101 women suffering from 103 breast tumours. Planar images and single photon emission computer tomography (SPET) were performed. After histological examination of the tumours, sensitivity, specificity and positive and negative predictive value were compared. ^99mTc-tetrofosmin and ^99mTc-MIBI showed low sensitivity in planar images (44% vs 46%, respectively). SPET improved sensitivity (70% vs 69%, respectively). Specificity in planar images was 83% and 87%, and it was even lower using SPET (70% vs 78%, respectively). Positive predictive value in planar images was 76% vs 81%, and it was not changed by SPET. Negative predictive value was low in planar images (54% vs 57%, respectively), but it was improved by using SPET (65% vs 67%, respectively). In conclusion, ^99mTc-tetrofosmin and ^99mTc-MIBI scintigraphy show similar diagnostic value in assessing suspicious breast lesions. Received 19 April and in revised form 1 August 1999