Tc-99m radio-guided completion thyroidectomy for differentiated thyroid carcinoma

Background:

The purpose of this study is to investigate whether or not radio-guided surgery has any beneficial effects on completion thyroidectomy (CT) and the associated complication rates.

Patients and Methods:

Twenty-seven patients were scheduled for CT, for thyroid carcinoma, from December 2004 to June 2005, and were included in the study. All the patients had had initial thyroid surgery in other centers and been referred to our clinic for CT. Operation findings and the effectiveness of Tc-99m radio-guided CT were analyzed.

Results:

The intraoperative mean ratio of thyroid activity to background activity counted with a gamma probe was 1.3 ± 0.3. Average operation timing was 74 ± 9 minutes. Postoperatively, no residual tissue was detected in any of the patients with ultrasonography and thyroid scintigraphy. In the first postoperative month, serum TSH level was 61 ± 16.4 mIU / L, when preoperatively it was 7.3 ± 3.1 mIU / L (P < 0.001). In the postoperative period, one patient experienced temporary hypoparathyroidism (3.9%). Permanent hypoparathyroidism or recurrent laryngeal nerve damage was not detected in any patient.

Conclusion:

Tc-99 radio-guided CT is a reliable surgical method, which provides the detection and removal of residual thyroid tissues with minimal complications.

The efficacy of (99m)Tc-MIBI scintimammography in the evaluation of breast lesions and axillary involvement: a comparison with X-rays mammography, ultrasonography and magnetic resonance imaging

This study was performed because the efficacy of technetium-99m methoxyisobutyl isonitrile scintimammography ((99m)Tc-MIBI-SM) in the evaluation of the breast lesions and axillary lymph node involvement in comparison with X-rays mammography (XRM), ultrasonography (US) and magnetic resonance imaging (MRI) has not been fully investigated. Forty six female patients were included in this study, with suspicious lesions detected in their breasts by palpation, by imaging modalities or clinically. All patients underwent (99m)Tc-MIBI-SM, US and MRI for the evaluation of breast lesions. All patients according to clinical situation and imaging studies underwent fine needle aspiration, mass extirpation, core biopsy, modified radical mastectomy or partial lumpectomy in order to confirm the nature of the lesions. Our results showed that (99m)Tc-MIBI-SM detected 15 of 16, US 11 of 16, XRM 13 of 16 and MRI 13 of 16 malignant lesions. Sensitivities were 93%, 68%, 81% and 81%, respectively. Among these cases there were 4 of 15 false positive (FP) results on SM whereas 4 of 11 on US, 11 of 13 on XRM and 8 of 13 on MRI. The specificities of the above modalities were 86%, 87%, 63% and 73%, respectively. The sensitivities of the above imaging modalities for the detection of axillary lymph node metastases were 55%, 55%, 11% and 77% for SM, US, XRM and MRI, respectively. The sensitivity and specificity of SM for the palpable lesions (n=31) were 100% and 84% and for the nonpalpable lesions (n=15) were 75% and 90%, respectively. In conclusion, although the number of patients studied was small it is the opinion of the authors that (99m)Tc-MIBI-SM has a much better sensitivity and less FP results in detecting malignant breast lesions than the other 3 modalities and also better sensitivity than XRM and MRI. Thus (99m)Tc-MIBI-SM can be included in the diagnostic algorithms for detecting malignancy in breast tumors.

Clearance of the high intestinal (18)F-FDG uptake associated with metformin after stopping the drug

PURPOSE

This study was done to determine whether interruption of metformin before (18)F-FDG PET/CT imaging could prevent the increased (18)F-FDG uptake in the intestine caused by this drug.

METHODS

Included in the study were 41 patients with known type 2 diabetes mellitus who were referred to our department for evaluation of various neoplastic diseases. Patients underwent two (18)F-FDG PET/CT scans, the first while they were on metformin and the second after they had stopped metformin. They stopped metformin and did not take any other oral antidiabetic medication starting 3 days before the second study and their blood glucose level was regulated with insulin when necessary to keep it within the range 5.55-8.33 mmol/l. FDG uptake was graded visually according to a four-point scale and semiquantitatively by recording the maximum standardized uptake value (SUVmax) in different bowel segments. A paired-samples t-test method was used to determine whether there was a significant difference between SUVmax measurements and visual analysis scores of the metabolic activity of the bowel in the PET/CT scans before and after stopping metformin.

RESULTS

Diffuse and intense (18)F-FDG uptake was observed in bowel segments of patients, and the activity in the colon was significantly decreased both visually and semiquantitatively in PET/CT scans performed after patients stopped metformin (p<0.05). There was a statistically significant decrease in activity in the small intestine on visual analysis (p<0.05), but semiquantitative measurements did not show a significant decrease in the SUVmax values in the duodenum or jejunum (p>0.05).

CONCLUSION

Metformin causes an increase in (18)F-FDG uptake in the bowel and stopping metformin before PET/CT study significantly decreased this unwanted uptake, especially in the colon, facilitating the interpretation of images obtained from the abdomen and preventing the obliteration of lesions.

Incidental detection of Sertoli-Leydig cell tumor by FDG PET/CT imaging in a patient with androgen insensitivity syndrome

A 29-year-old female patient who was being followed up for differentiated papillary thyroid carcinoma was referred to us for exploration of any possible metastasis since her serum thyroglobulin levels were high. The patient underwent an F-18 fluorodeoxyglucose positron emission tomography study, and a pathologically increased FDG uptake at the left lower abdomen was detected corresponding to a solid, cystic lesion on CT images. The patient had a history of primary amenorrhea and, together with the magnetic resonance imaging findings of absent uterus, short and blind end vagina, a diagnosis of androgen insensitivity syndrome was made. The patient underwent laparoscopic left pelvic mass resection, and the histopathology of the lesion revealed Sertoli-Leydig cell tumor.