Ho-Cheon Song

Double-phase Tc-99m sestamibi scintimammography to assess angiogenesis and P-glycoprotein expression in patients with untreated breast cancer.

This study evaluated the relation of Tc-99m sestamibi (MIBI) uptake and washout in untreated breast cancer with immunohistochemically determined angiogenesis and P-glycoprotein expression. Thirty-one patients with untreated breast cancer were studied prospectively. Tc-99m MIBI scintigraphy and immunohistochemical analyses of angiogenesis and P-glycoprotein expression were used to evaluate surgically removed tumor tissues. Anterior and both lateral planar images were acquired 10 and 180 minutes after intravenous injection of 740 MBq (20 mCi) Tc-99m MIBI. The tumor-to-normal breast ratio (T:N) and washout index (early T:N - late T:N divided by early T:N) were calculated. A significant correlation was found between angiogenesis and T:N at early and late images. Pearsons correlation coefficients and probability values were r = 0.54, P = 0.002 at early images and r = 0.47, P = 0.008 at late images. The T:N of both early and late images were not different among different groups of P-glycoprotein expression (P = 0.367 and P = 0.113, respectively), although the washout index was significantly different among the groups (P = 0.001). A strong correlation was found between the washout index and P-glycoprotein expression (r = 0.67, P < 0.01). Double-phase scintimammography to assess the early tumoral uptake and washout of Tc-99m MIBI can be used as a simple functional test for in vivo imaging of tumoral angiogenesis and P-glycoprotein expression in patients with untreated breast cancer.

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

Purpose To evaluate the incidence and origin of abnormal focal pulmonary uptake during myocardial perfusion SPECT imaging (MSPECT). Methods For evaluation of chest pain, 790 men and 581 women (mean age, 56 ± 13 years) underwent MSPECT. All of them received adenosine for pharmacologic stress and Tc-99m tetrofosmin (TF, n = 817) or Tc-99m sestamibi (MIBI, n = 554) for myocardial perfusion imaging. Results Review of chest radiography with or without computed tomography revealed 111 (8.1%) focal pulmonary diseases. Among them, 38 (34.2%) showed focal pulmonary uptake (TF, 22; MIBI, 16); 27 (30.7%) of 88 showed previous pulmonary tuberculosis; 2 of 10 (20%) benign pulmonary nodules; 4 of 5 (80%) metastatic lung cancers; 2 of 4 (50%) primary lung cancers; and 3 of 4 (75%) pneumonias. No difference in uptake was noted for the two imaging agents. Intensity of uptake did not vary with origin of the uptake. Focal abnormal pulmonary uptake was found in 2.8% of patients undergoing MSPECT and in 34.2% of patients in whom radiological examinations showed regional pulmonary disease. In patients with abnormal pulmonary uptake on MSPECT, 16% had a malignant lesion, whereas 75% of patients with a pulmonary nodule shown on radiography and focal pulmonary uptake on MSPECT had a malignant lesion. Conclusions Although the incidence of abnormal pulmonary uptake during MSPECT was very low, the incidence of malignant lesions in the patients with nodular pulmonary uptake was relatively high.

Dipyridamole modulated Tc-99m sestamibi lung SPECT in small cell lung cancer

PURPOSE In this study, the authors wanted to determine whether dipyridamole-modulated MIBI (dipyridamole-MIBI) could enhance the prediction of the response to chemotherapy in patients with small cell lung cancer. METHODS Twenty-seven patients with biopsy-proved small cell lung cancer (25 men, 2 women; mean age, 61 +/- 7 years) underwent dipyridamole-MIBI SPECT 3 to 7 days before starting chemotherapy (80 mg/m2 etoposide and 80 mg/m2 cisplatin every 3 or 4 weeks for at least two cycles). Tomographic images before and after dipyridamole (0.84 mg/kg) were acquired 1 hour after injection of 370 (10 mCi) and 1,110 (30 mCi) MBq MIBI, respectively. The response to chemotherapy was grouped as specified as complete response (CR), partial (PR), no change (NC), or progressive disease (PD), according to the change in tumor size on chest roentgenography and CT. Patients showing CR and PR were classified as responders, and those who showed NC and PD were considered nonresponders. RESULTS Among the 27 patients, 22 were responders (3 CR, 19 PR) and 5 were nonresponders (3 NC, 2 PD). The tumor-to-normal lung ratio (T:NL) of responders was significantly higher than that of nonresponders. The diagnostic accuracy of the T:NL ratio to differentiate responders and nonresponders was 33.3%, with a cutoff value of 2.5, which was significantly improved to 77.8% when an increased T:NL ratio after dipyridamole was assigned to a nonresponder. Furthermore, all patients with CR showed diminished T:NL ratios after dipyridamole, and all patients with NR showed an increased T:NL ratio after dipyridamole. CONCLUSION Dipyridamole-MIBI SPECT could enhance the prediction of response to chemotherapy in patients with small cell lung cancer.

Diffuse soft tissue uptake of I-131 after post-thyroidectomy ablation therapy for thyroid cancer.

1-131-induced cellulitis after 1-131 ablation of a post-thyroidectomy remnant and metastatic differentiated thyroid cancer is rare. The authors describe a 45-year-old woman in whom painful neck swelling developed and diffuse soft tissue uptake of I-131 appeared after ablation therapy. She received 7.4 GBq (200 mCi) 1-131 for papillary thyroid cancer. On the second hospital day, painful swelling of the neck and pharyngeal hyperemia developed. I-131 scintigraphy showed greatly increased uptake in metastatic lymph nodes with diffuse increased uptake in the soft tissues of the neck. The diffuse soft tissue uptake cleared as the painful swelling subsided.

Tc-99m pyrophosphate uptake in small areas of myocardial injury produced by radiofrequency catheter ablation of arrhythmias

Radiofrequency produces small circumscribed areas of myocardial damage and is now used most commonly for ablation of arrhythmias. The proper position of a catheter can be determined easily by fluoroscopy. However, the degree of tissue destruction cannot be assessed by electronic or radiographic techniques. Seventeen patients with arrhythmia were studied 2 days after radiofrequency catheter ablation of arrhythmias by Tc-99m pyrophosphate scintigraphy. In 14 of the 17 patients (82.4%), myocardial lesions produced by radiofrequency ablation were successfully demonstrated by SPECT imaging, whereas none showed positive uptake on planar images. Two cases are illustrated.