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Detection of Bilateral Multifocal Breast Cancer Using Tc-99m Sestamibi Imaging: The Role of Delayed Imaging

PURPOSE Early determination that breast cancer is bilateral and multifocal can change therapy strategy and, subsequently, mortality and morbidity rates. The authors present a case with bilateral, multifocal breast cancer detected only by Tc-99m sestamibi imaging. METHODS Early and delayed Tc-99m sestamibi imaging and dynamic MRI were performed in a patient with a right-sided lesion shown on mammography. RESULTS Although early Tc-99m sestamibi imaging detected bilateral breast cancer foci, both dynamic MRI and mammography missed the lesion in the left breast. Additional lesions seen on delayed Tc-99m sestamibi images of the left breast, which were initially thought to be benign, completely disappeared after concomitant chemotherapy and radiotherapy, suggesting multifocal malignant lesions in the left breast. CONCLUSION This case suggests that Tc-99m sestamibi may be useful for detecting bilateral cancer, and delayed imaging may give additional information regarding the possible multifocal nature of the disease.

Effect of chemotherapy on pulmonary epithelial permeability in lung cancer

The aim of this study is to investigate the effect of one-course chemotherapy on the pulmonary epithelial permeability. Eighteen patients (18 male; mean age: 59+/-10 years) with lung cancer (11 non-small cell, 7 small cell) inhaled 40 mCi (1,480 MBq) (99m)Tc-diethylenetriaminepentaacetic acid (DTPA). Thirty images of 1-min duration were acquired from posterior projection. The first 7 min of the decay-corrected time activity curves were used to calculate lung clearance half-time. Clearance half-times of (99m)Tc-DTPA from the peripheral regions of the lungs were 42+/-19 min before and 56+/-34 min after chemotherapy (p=0.009); from the central regions, clearance half-times were 112+/-94 min before and 160+/-125 min after chemotherapy (p=0.005). This decrease in clearance rate might be related to decreasing mucociliary clearance rate due to the toxic effect of the chemotherapy regimen on cilia movement and/or mucus structure. (99m)Tc-DTPA radioaerosol study can be used to monitor the toxic effects of chemotherapy on the pulmonary epithelium and possibly on mucociliary function.

Basal and activational 99Tcm-HMPAO brain SPECT in Alzheimer's disease.

Early diagnosis in Alzheimers disease (AD) is important for the administration of new treatments. The purpose of this study was to differentiate mildly/moderately demented AD patients from normal controls by means of activational brain SPECT, and to investigate the correlation between regional cerebral blood flow and dementia severity. Activational brain SPECT was performed 1 week after basal brain SPECT in 12 mild/moderate AD patients according to NINCDS-ADRDA criteria (mean age 69±7 years) and in seven healthy, age-matched, volunteer controls (mean age 65±9 years). In order to activate the parietal cortex, patients were asked to subtract serial 5s from 100, 2 min before and after the intravenous administration of 925 MBq technetium-99m labelled D,L-hexamethyl-propylene amine oxime (99Tcm-HMPAO). Using a three-headed gamma camera equipped with high resolution collimators, 128 images of 35 s duration in a 64×64 matrix were obtained over 360°. Region to whole brain ratios (R/WB) were calculated in three consecutive transaxial slices 2 pixels thick above the orbitomeatal line, and the activation percentage was calculated. No statistical difference was detected between AD patients and normal controls for parietal cortex activation. The correlation coefficient between the Mini-Mental State Examination (MMSE) scoring and the activation percentage was 0.475 in normal controls and 0.175 in AD patients for the left anterior parietal cortex, and 0.353 in normal controls and 0.146 in AD patients for the right anterior parietal cortex. In a visual evaluation of parietal cortex activation, 50% of AD patients were able to activate the parietal cortex, whereas 86% of the normal controls could do so. In our current study, the subtraction of serial 5s was not regarded as a promising task. Further studies are needed to clarify the importance of such tasks in the differential diagnosis of mild/moderate AD patients from normal elderly.

Sublingual nitrate plus 99Tcm-tetrofosmin infusion in the detection of severely ischaemic but viable myocardium : A comparative study with stress, redistribution, reinjection and late redistribution 201Tl imaging

To investigate the role of sublingual nitrate plus 99Tcm-tetrofosmin infusion in the detection of severely ischaemic but viable myocardium, we selected 25 patients with coronary artery disease who had at least one fixed segmental defect during conventional stress-redistribution (ST-RD) 201Tl single photon emission tomographic (SPET) imaging. Reinjection (RI) and 24 h late redistribution (LRD) imaging were also performed. Within a week of 201Tl imaging, one-day rest-stress (R-ST) 99Tcm-tetrofosmin SPET was performed with the same stress levels. The following day, 99Tcm-tetrofosmin was infused over 1 h immediately after sublingual nitrate administration and SPET images (N + Inf) were acquired. Of 100 fixed defects on R-ST 99Tcm-tetrofosmin imaging, 15 were reversible on N + Inf 99Tcm-tetrofosmin imaging. There was 91% concordance between ST-RD/RI/LRD 201Tl and R-ST/N + Inf 99Tcm-tetrofosmin imaging regarding reversibility. We conclude that N + Inf 99Tcm-tetrofosmin imaging may be clinically useful in the detection of severely ischaemic but viable myocardium.

The role of technetium-99m-HMPAO-labeled WBC scintigraphy in the diagnosis of orbital cellulitis

Bacterial orbital cellulitis is an infection of the soft tissues behind the orbital septum. Cellulitis is seen as a poorly defined area of increased CT density or T2 signal intensity within the fat. There is an amorphous enhancement following contrast infusion. Radiolabeled leukocytes or granulocytes are now established widely as a means of localizing various forms of inflammatory disease and infections. We report a case of orbital cellulitis detected with Tc-99m-HMPAO-labeled WBC scintigraphy and three-phase bone scintigraphy. Tc-99m-HMPAO-labeled WBC scintigraphy was superior to bone scintigraphy in delineating the extension and limits of the infectious process in the orbita. Tc-99m-HMPAO-labeled WBC scintigraphy is appropriate in the investigation of such infectious lesions, leading to early diagnosis and therapy to avoid severe complications.

Infusion versus bolus injection of Tc-99m tetrofosmin in the identification of viable myocardium.

In this report, a patient with 100% RCA stenosis and prominent collaterals, in which TI-201 rest/redistribution and Tc-99m tetrofosmin infusion imaging findings were compatible with viable myocardium in contrast to Tc-99m tetrofosmin bolus imaging is presented. Viability was confirmed with improvement of wall motion and perfusion 3 months after revascularization. Infusion of Tc-99m tetrofosmin rather than a bolus injection may be a more reliable technique in the identification of severely ischemic but viable myocardium.

Tc-99m sestamibi imaging as an indicator of P-glycoprotein expression in metastatic pheochromocytoma

A 73-year-old man with metastatic pheochromocytoma demonstrated areas of elevated I-131 MIBG uptake and no Tc-99m sestamibi uptake in the presence of marked blood flow, suggesting P-glycoprotein-mediated multidrug resistance. Tc-99m sestamibi scintigraphy may be used in predicting the chemotherapeutic response of P-glycoprotein-related cytotoxic drugs such as anthracyclines, vinca alkaloids, and epipodophyllotoxins. Moreover, in metastatic pheochromocytoma, it may change the therapy strategy, such as cytotoxic chemotherapy versus targeting therapy with 1-131 MIBG or combined therapy with the addition of a P-glycoprotein-reversing agent, provided that the patient is surveyed first with Tc-99m sestamibi and 1-131 MIBG.

Bilateral increased Tl-201 uptake of lacrimal glands caused by crying of a child during injection.

A 4-year-old boy with retinoblastoma whose left eye was enucleated was referred for tumor imaging. TI-201 tumor imaging was performed to detect possible recurrence of the primary tumor. He was agitated and cried during injection, and as a result bilateral increased lacrimal gland uptake was seen on early images. Crying during injection should be excluded, especially in children, when significant lacrimal gland uptake of TI-201 is present.