Clinical positron imaging : official journal of the Institute for Clinical P.E.T最新文献

Since the comparative value of several nuclear medicine investigations for breast cancer has not been established, the rationale of this study was to examine the diagnostic performances of F-18-fluorodeoxyglucose (FDG) and Tc-99m-tetrofosmin both in single photon emission computed tomography (SPECT) and planar technique in an intraindividual comparative study.

A total of 54 patients with suspected breast cancer (48 malignant and 9 benign lesions) was investigated by planar and SPECT imaging with both FDG and tetrofosmin within the last preoperative week. Pathohistological confirmation of the diagnosis was obtained in all patients.

Overall sensitivites/specificities of FDG planar imaging and SPECT and tetrofosmin planar imaging and SPECT were 56%/78%, 81%/89%, 59%/57%, and 63%/86%, respectively. For tumors ⩽2 cm the respective figures were 27%/83%, 68%/100%, 41%/80%, and 50% /80%, and for tumors >2 cm 81%/67%, 92%/67%, 75%/50%, and 75%/100%. Sensitivity was higher with FDG SPECT than with the other imaging modalities $\text{P = 0}$ and significantly lower for tumors ⩽2 cm with all the techniques investigated. In 20 out of 21 patients with diverging scintigraphic findings, FDG SPECT was either true positive or true negative. In 15 patients with axillary lymph node metastases, sensitivities were 33%, 73%, 36%, and 50%, respectively.

In conclusion, sensitivity of FDG SPECT for breast cancer and axillary lymph node metastases is superior to FDG planar imaging and to tetrofosmin planar imaging and SPECT. For tumors ⩽2 cm and axillary lymph node metastases, none of the imaging modalities yielded acceptable results. FDG SPECT seems a suitable imaging procedure for breast tumors >2 cm, if dedicated PET is not available.

This report describes 3 cases of primary hyperparathyroidism (PHP) in which presurgical localization of the culprit lesions was essential. In 2 cases, the initial parathyroid surgery had failed to restore normal levels of either parathyroid hormone (PTH) or calcium (Ca⁺⁺). In each of these cases experienced surgeons performed the initial parathyroid explorations. In one of these 2 cases, a positive ^99mTc sestamibi (MIBI) scan was obtained prior to the initial surgery. ¹¹C-methionine-positron emission tomography (PET) scans and magnetic resonance imaging (MRI) studies were performed prior to repeat surgical exploration with these data coregistered (the digital data sets from each modality were spatially aligned). In each case, the ¹¹C-methionine-PET studies identified metabolically active tumors whose anatomic locations were accurately determined on the PET coregistration. The third case had previously undergone a thyroidectomy and modified right radical neck dissection for removal of a thyroid cancer and regional lymph node metastases. Following the diagnosis of PHP, MIBI, thallium, and ultrasound studies were performed and were all negative. ¹¹C-methionine-PET and MRI were performed identifying a parathyroid adenoma in the prior surgical field. In these 3 cases culprit lesions were readily located at surgery, excised and confirmed as parathyroid neoplasms. This ¹¹C-methionine PET-MRI coregistration technique appears to be effective at localizing parathyroid neoplasms in high risk patients with PHP in the setting of initially failed surgery or when PHP occurs following previous regional neck surgery.

Positron emission tomography (PET) using F-18-fluoro-2-deoxy-d-glucose(F-18-FDG) is gaining acceptance as a useful imaging method for head and neck tumors. Results of 59 PET scans done on 45 patients with head and neck tumors were evaluated retrospectively. Thirty-six patients had prior treatment consisting of surgery, radiation therapy, chemotherapy, or a combination of these modalities. PET results were compared to computed tomography $\text{CT}\text{N}\text{= 38}$ and magnetic resonance imaging $\text{MRI}\text{N}\text{= 14}$ results and validated by histologic findings or survival. PET identified 36 out of 37 tumors (sensitivity 97%) and 18 of 22 benign processes (specificity 82%). Tumor was ruled out in 18 out of 19 patients. For CT, the sensitivity was 80% (20/25) and specificity was 31% (4/13). FDG-PET facilitates differentiation of recurrent head and neck tumors from treatment related changes sometimes difficult to characterize by CT or MRI and may have a significant impact on the management of patients reducing morbidity and costs.

According to the Papineau technique, open autogenous cancellous bone grafting procedures were performed in tibial bone defects. Repeated positron emission tomography (PET) examinations with 2 tracers, [¹⁵O]water to assess blood flow and [¹⁸F]fluoride to assess bone metabolism, showed no evidence of recirculation of the bone graft within the first week.

We are reporting the case of a 37-year-old woman with rising β-human chorionic gonadotropin (HCG) levels over 4 years. Curettage was performed 5 times and diagnostic laparoscopy twice, but no trophoblastic tissue was found. Vaginal ultrasound and power Doppler sonography showed a solid tumor of the anterior uterus wall with high vascularization. ¹⁸F-2-deoxy-D-glucose-positron emission tomography (FDG-PET) revealed a single focus of FDG uptake in projection of the uterus. Sonographically, the tumor of the uterus appeared like a leiomyoma. Thus focal FDG uptake was the sole indicator for a malignant trophoblastic tumor. Histological examination of the tumor revealed a choriocarcinoma.

Objective and Methods: This study was undertaken to find the role of fluorine-18-fluorodeoxyglucose (F18-FDG) in the diagnostic work-up of febrile Acquired Immune Deficiency Syndrome (AIDS) patients. Forty-seven (42 male and 5 female; mean age = 40.3 years) febrile patients with AIDS underwent imaging with F18-FDG by Dual Head Coincidence Imaging (DHCI). Findings were correlated with other imaging modalities.

Results: Our data show good sensitivity for scanning with F18-FDG by DHCI in determining the extent of Castleman's disease, lymphoma, Kaposi's sarcoma (KS), adenocarcinoma, and germ cell carcinoma. Various opportunistic infections also manifest with increased F18-FDG uptake.

Conclusion: Total-body imaging can be done with F18-FDG with better resolution and a shorter procedure time compared to imaging with Gallium-67 (Ga-67). Furthermore, F18-FDG is more sensitive than Ga-67 for evaluating extent of involvement in various pathologies affecting AIDS patients. The new technology of DHCI is a good alternative for hospitals with no dedicated positron emission tomography (PET) scanner.