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

Purpose: To retrospectively evaluate the contribution of 18F-fluorodeoxy-glucose-positron emission tomography (FDG-PET) to the diagnosis and clinical management of patients who were suspected of recurrent ovarian carcinoma, based on elevated tumor markers levels with normal or equivocal computed tomography (CT) or nuclear magnetic resonance (NMR).

Procedures: 20 patients with these characteristics underwent FDG-PET. PET findings were confirmed in 14, in 7 by surgery, and in the other 7 by clinical course.

Results: Recurrence was confirmed in 12 patients, all with FDG-PET positive. In other 2, recurrence was rule out and in 1, FDG-PET was negative. FDG-PET accuracy was 93% with 4 surgeries avoided and guided other 6.

Conclusions: FDG-PET is an useful technique for detecting recurrent ovarian carcinoma suspected by elevated tumor markers levels and normal or equivocal results in the morphologic imaging techniques and has an important clinical impact on the management of these patients.

Purpose: The clinical use of PET FDG in the work-up of patients with bone and soft tissue malignant tumors is rapidly increasing. The recognition of any source of artifact, therefore, is important to avoid interpretation pitfalls.

Procedures: Two patients with complete knee joint replacement by metallic prosthesis in the course of their treatment for malignant bone and soft tissue sarcoma were evaluated by PET F-18 FDG imaging using a dual head coincidence gamma camera.

Results: Both studies demonstrated in the attenuation-corrected images intense increase activity at the joint space between the metallic prosthetic surfaces at the level of the knee joint. No uptake, however, was noted in the same location on the non-attenuation-corrected images. Subsequent bone and thallium-201 scans confirmed the absence of tumor recurrence in the first patient. The second patient had multiple follow up F-18 FDG scans over a period of 16 months that show no changes from the baseline study.

Conclusion: In the F-18 FDG PET images of patients with total knee metallic prosthesis, an intense activity tends to be seen in the joint space, only in the attenuation-corrected images. Such pattern of uptake is considered artifactual and should always be verified in the non-attenuated images.

Purpose: In this work, we describe five oncology patients whose clinical management were uniquely benefited by a novel scanner that acquires positron emission tomography (PET) and x-ray computed tomography (CT) in the same imaging session.

Procedures: Co-registered 2-[F¹⁸]-fluoro-2-deoxy-D-glucose (FDG)-PET and CT images were acquired using a combined PET/CT scanner. Pathology and clinical follow-up data were used to confirm PET/CT scan results.

Results: The combined PET/CT scanner demonstrated the ability to distinguish malignant lesions from normal physiologic FDG uptake in the striated muscles of the head and neck as well as excretory and bowel activity in the abdomen and pelvis. Additionally, the technology positively affected patient management through localization for surgical and radiation therapy planning as well as assessment of tumor response.

Conclusion: Our experience indicates that simultaneous acquisition of co-registered PET and CT images enabled physicians to more precisely discriminate between physiologic and malignant FDG uptake and more accurately localize lesions, improving the value of diagnostic PET in oncologic applications.

This retrospective study was done to evaluate the utility of 2-[F-18]fluoro-2-deoxy-D-glucose positron emission tomography (F-18-FDG PET) in identifying primary and recurrent breast cancer and lymph node metastases. One hundred whole-body PET scans of 87 patients were reviewed. PET results obtained with F-18-FDG and an ECAT/EXACT-921 or an ECAT-931 (Siemens/CTI) were based on visual interpretation, or standardized uptake values (SUVs), related to histology and also compared to computerized tomography (CT) and mammography results. The sensitivity for PET in detecting primary (N = 35 studies) and recurrent breast cancer (N = 65 studies) was 96% and 85% with a specificity of 91% and 73%. The sensitivity for lymph node metastases at the time of initial diagnosis was 100% with a specificity of 100%. Quantitative SUV information did not improve the accuracy of F-18-FDG PET in identifying primary breast cancers. The results suggest that whole-body PET is useful in detecting recurrence or metastases, may be useful in detecting lymph node metastases prior to initial axillary lymph node dissection, but is less sensitive in excluding axillary lymph nodes metastases later in the course of the disease.

The application of positron emission tomography imaging with ¹⁸F-fluorodeoxyglucose (FDG) to the extracranial head and neck has been proven to be effective in the detection and staging of malignancy. The FDG uptake of normal laryngeal tissue is symmetric and low, while benign lesions typically have only slight increases in FDG uptake. We report a case of asymmetric, superphysiologic FDG uptake in the contralateral vocal cord of a patient with a unilateral vocal cord paralysis secondary to sacrifice of the recurrent laryngeal nerve during pneumonectomy for lung cancer. The FDG uptake of the non-paralyzed vocal cord was increased multiple-fold, placing it well within the range of malignancy. Use of unique, combined PET-CT imaging localized the high FDG uptake to the non-paralyzed vocal cord, and laryngoscopy confirmed no evidence of malignancy in the vocal cord. This case demonstrates that a benign cause of false-positive FDG-PET imaging may be encountered during evaluation of the extracranial head and neck for malignancy. We aim to alert the reader to this potential pitfall in the interpretation of FDG-PET imaging, which can be resolved with the use of combined PET-CT imaging and clinical correlation.

Purpose: ¹⁸F-Fluorodeoxyglucose-positron emission tomography (FDG-PET) is the superior imaging modality for detection of primary and recurrent colorectal cancer compared to magnetic resonance imaging (MRI) or computerized tomography (CT). We investigated the feasibility of developing intraoperative procedures for detection of FDG in tumor deposits in order to assist the surgeon in achieving an optimal reduction of tumor burden.

Procedures: Fourteen patients (45–83 years of age) were scanned using FDG-PET followed by Gamma Detection Probe evaluation at laparotomy. One patient did not have a pre-operative FDG-PET scan. The collimated detector probe contained a CdZnTe crystal (7mm diameter × 2mm thick). We used a lower window setting of 200 KeV and an open upper window setting. Fasted patients were given an IV bolus of FDG (4.0–5.7 mCi) 15–20 minutes prior to preparation for surgery. Catheterization and the diuretic Lasix were used to remove FDG activity from the bladder. The time from FDG injection to intraoperative GDP data acquisition varied from 58–110 minutes.

Results: In all patients, the GDP detected background activity in normal tissues (aorta, colon, liver, kidney, abdominal wall, mesentery, and urinary bladder). The GDP correctly identified single or multiple tumor foci in 13/14 patients as noted by an audible signal from the control unit (3 S.D. above counts obtained from normal tissues). These tumor foci corresponded to regions of high FDG uptake as seen on FDG-PET scans. The one case that the GDP did not localize was a recurrent mucin pseudomyxoma-producing tumor (acellular, mucinous deposits). Ex vivo GDP evaluations demonstrated significant tumor:normal adjacent tissue activity (audible signals in 6/6 tumor samples tested).

Conclusions: These data demonstrate that tumors identified from pre-operative whole-body PET scans can be localized during surgery utilizing a gamma probe detector and FDG.

Purpose: We discuss three cases of patients with small polypoid lesions of gallbladder in which we successfully differentiated the malignancy or benignity preoperatively using positron emission tomography (PET) scanning with ¹⁸F-labelled deoxyglucose (FDG).

Methods and Results: The first case involves a 47-year-old woman who had a 15 × 10 mm polypoid lesion of the gallbladder. FDG-PET was performed and revealed no FDG uptake. The histopathological diagnosis was a cholesterol polyp. The second case is a 56-year-old woman who had a 22 × 8 mm polypoid lesion in the neck of the gallbladder and wall-thickening of the fundus. FDG-PET was performed and no FDG uptake was found. The postoperative diagnosis was pseudo-tumorous sludge in the neck and adenomyomatosis of the fundus. The third case is a 77-year-old man who had a 15 × 15 mm polypoid lesion in the gallbladder. PET revealed a focus of FDG uptake at the site of the gallbladder. The histopathologic diagnosis was adenocarcinoma. Focal FDG uptake was the sole indicator of a malignant tumor of the gallbladder.

Conclusions: FDG-PET may become one of the most useful tools for the accurate preoperative diagnosis of gallbladder carcinoma.