Language localization with activation positron emission tomography scanning.

We report the first instance of the use of 3-dimensional magnetic resonance imaging anatomically correlated to positron emission tomography (PET) scanning to identify language areas in a patient with an arteriovenous malformation (AVM) in the posterior speech region. The patient was a 24-year-old right-handed woman with an angiographically proven AVM (3-4 cm) in the left mid-posterior second temporal convolution in whom a left intracarotid injection of sodium Amytal produced significant language disruption. A baseline PET cerebral blood flow study identified the AVM, and an activation PET scan performed during the reading and speaking of simple words showed increased activity in the left parastriate cortex (the second visual area), in the left posterior third frontal convolution (Broca's area), and in the left inferior and midtemporal gyri (Wernicke's area). Increased activity was also noted in the right and left transverse temporal (Heschl's) gyri, in the left precentral gyrus, in the left medial superior frontal gyrus (the supplementary motor area), and in the right cerebellum. We conclude that activation PET scanning is useful in the preoperative assessment of patients who harbor cerebral AVMs in classically described speech regions.     

Stereotactic imaging for radiosurgery: localization accuracy of magnetic resonance imaging and positron emission tomography compared with computed tomography

Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) provide complementary information for treatment planning in stereotactic radiosurgery. We evaluated the localization accuracy of MRI and PET compared with CT. Two kinds of phantoms applicable to the Leksell G stereotactic skull frame (Elekta, Tokyo) were developed. Deviations of measured coordinates at target points (x = 50, 100, 150; y = 50, 100, 150) were determined on different axial planes (z = 30-140 for MRI and CT study and Z = 50-120 for PET and CT study). For MRI, the deviations were no more than 0.8 mm in each direction. For PET, the deviations were no more than 2.7 mm. For both imaging modalities studied, accuracy was at or below the imaging resolution (pixel size) and should be considered useful for clinical stereotactic planning purposes.     

Cortical dysplasia and epilepsy: functional imaging using single photon emission computed tomography and positron emission tomography.

Functional imaging using single photon emission CT and positron emission tomography have made important contributions to the evaluation of patients with medically intractable epilepsy and cortical dysplasia by identifying patients who previously were not considered surgical candidates. This article reviews the role of functional imaging in the presurgical evaluation of this patient population.     

Combined positron emission tomography/computed tomography imaging of recurrent thyroid cancer.

OBJECTIVE: The study goal was to evaluate the use of combined positron emission tomography/computed tomography (PET/CT) imaging for localization of recurrent disease in thyroid cancer patients. STUDY DESIGN AND SETTING: Eight patients with suspected recurrence of thyroid cancer on the basis of elevated serum thyroglobulin or calcitonin levels underwent combined PET/CT imaging on a prototype device. All 8 patients had previously undergone total thyroidectomy and (131)I ablation for thyroid carcinoma. Patients with papillary carcinoma had negative (131)I scans. RESULTS: Eight patients underwent combined PET/CT scanning. Four (50%) of 8 patients underwent PET/CT indicating recurrence in the head and neck. A total of 11 lesions in these 4 patients were suspicious for recurrence on combined PET/CT imaging. Three patients with 8 lesions suspicious for recurrence on PET/CT underwent surgical removal of disease. All 3 patients had pathologic confirmation of recurrence, with 6 (75.0%) of 8 lesions being positive. CONCLUSION: Combined PET/CT imaging is a valuable tool for the diagnosis and anatomic localization of recurrent thyroid cancer.     

Resection of gliomas using positron emission tomography/computed tomography neuronavigation

Two patients presented with provisional diagnoses of glioma. Computed tomography (CT) and magnetic resonance imaging failed to show the boundaries of the tumor clearly. Positron emission tomography (PET)/CT with [(18)F]fluorodeoxyglucose and (11)C-methionine clearly showed the location, extent, and heterogeneity of the tumors. The tumors were resected under PET/CT neuronavigation guidance. Histological examination of the specimens showed that PET/CT neuronavigation provided reliable distinction between normal brain and glioma, and that the uptake of PET tracers can indicate the degree of proliferation.     

Frontal atypical teratoid/rhabdoid tumor evaluated by single-photon emission computerized tomography and positron emission tomography

A case of frontal atypical teratoid/rhabdoid tumor (AT/RT) was presented in the findings of single-photon emission computerized tomography (SPECT) using 201Tl-chloride (Tl) and 123I-metaiodobenzylguanidine (MIBG), and positron emission tomography using 18F-fluorodeoxyglucose (FDG) and (11C-methyl)-L-methionine (Met). A 16-year-old female had an episode of Jacksonian seizures one month prior to admission. CT scans showed an isodensity mass with heterogeneous enhancement in the left frontal lobe. MR images revealed a tumor with solid and cystic components and perifocal edema. SPECT demonstrated intense accumulation of Tl and MIBG in the enhancing lesion 15 min and 30 min after intravenous injection of tracers, respectively. The 6-hr delayed SPECT showed no retention of MIBG in the enhancing lesion. FDG-PET and Met-PET revealed high uptake of tracers in the enhancing lesion. Met did not accumulate in the frontal white matter, which appeared hyperintense on T2-weighted MR images. The patient underwent an uneventful extirpation of the solid mass, where Met had accumulated. Microscopically, the solid tumor contained rhabdoid cells, spindle-shaped cells resembling mesenchymal cells, and nests of small cells. The tumor cells were immunoreactive for vimentin, cytokeratin, and epithelial membrane antigen. The MIB-1 labeling index was 25%. The histological diagnosis was AT/RT. Postoperative course was uneventful. A dose of 32.4 Gy was administrated to the whole brain and a boost of 27.8 Gy to the T2-hyperintensity lesion. Five months after the radiotherapy, MRI showed neither abnormal enhancing lesions nor the T2-hyperintensity lesion. Multifarious studies using SPECT and PET are useful for differential diagnosis and for choosing optimal therapeutic strategy for this type of tumor.     

Detection of recurrent and metastatic colorectal cancer: Comparison of positron emission tomography and computed tomography

Background: This study evaluates the clinical value of positron emission tomography (PET) with 2-[F-18] fluoro-2-deoxy-D-glucose (FDG) as compared to computed tomography (CT) in patients with suspected recurrent or metastatic colorectal cancer (CRC). Methods: A retrospective review of the records of 58 patients who had FDG-PET for evaluation of recurrent or advanced primary CRC was performed. FDG-PET results were compared with those of CT and correlated with operative and histopathologic findings, or with clinical course and autopsy reports. Results: Recurrent or advanced primary CRC was diagnosed in 40 and 11 patients, respectively. The sensitivity and specificity of FDG-PET were 91% and 100% for detecting local pelvic recurrence, and 95% and 100% for hepatic metastases. These values were superior to CT, which had sensitivity and specificity of 52% and 80% for detecting pelvic recurrence, and 74% and 85% for hepatic metastases. FDG-PET correctly identified pelvic recurrence in 19 of 21 patients; CT was negative in 6 of these patients and equivocal in 4. FDG-PET was superior to CT in detecting multiple hepatic lesions and influenced clinical management in 10 of 23 (43%) patients. Conclusion: FDG-PET is more sensitive than CT in the clinical assessment of patients with recurrent or metastatic CRC, and provides an accurate means of selecting appropriate treatment for these patients. Presented at the 50th Annual Cancer Symposium of The Society of Surgical Oncology, Chicago, Illinois, March 20–23, 1997.     

Detection of aortic graft infection by 18-fluorodeoxyglucose positron emission tomography combined with computed tomography

Functional in vivo molecular imaging is provided with 18-fluorodeoxyglucose positron emission tomography (FDG-PET), which can detect cells with high glucose turnover. FDG-PET is an established imaging tool in oncology but has also been used in infectious and inflammatory diseases. PET combined with computed tomography (PET/CT) shows the metabolic activity with precise anatomic localization. More than 2000 scanners have now been installed worldwide, and with better availability, this hybrid method has the potential to become an important imaging tool in the management of suspected aortic graft infections, especially in patients with low-grade graft infection. We report a patient with a suspected aortic graft infection that was confirmed and anatomically localized by FDG-PET/CT. An extra-anatomic bypass and extirpation of the aortic graft was performed. The perioperative location of the graft infection coincided exactly with the place of FDG uptake shown on PET/CT. The patient had an uneventful postoperative recovery and did well during 6 months of follow-up.     

Prostate cancer localization with 18fluorine fluorocholine positron emission tomography

PURPOSE: We evaluated positron emission tomography (PET) with fluorine fluorocholine (F FCH) for the pretreatment localization of prostate cancer. MATERIALS AND METHODS: A total of 17 patients with prostate cancer who had not yet received treatment for the disease underwent whole body PET following intravenous administration of 3.3 to 4 MBq/kg F FCH. PET findings were compared with the results of prostate sextant biopsy and other imaging studies, and the clinical course. Tracer uptake in prostate sextants was measured as a maximum standardized uptake value (SUVmax) and evaluated as a predictor of the prostate sextant biopsy result by ROC analysis. RESULTS: Prostate sextants positive for malignancy on biopsy demonstrated significantly higher SUVmax than biopsy negative sextants (mean 5.5 vs 3.3, p <0.001). In all 6 cases in which biopsy identified malignancy on only 1 side of the prostate it was possible to identify correctly the affected side based on higher SUVmax. Area under the ROC curve for SUVmax as a discriminator of biopsy positive sextants was 0.86. In 2 patients PET demonstrated areas of abnormal uptake in the retroperitoneum. Computerized tomography confirmed the presence of retroperitoneal lymphadenopathy in these areas. In the 2 patients these lesions regressed following hormonal treatment for prostate cancer. CONCLUSIONS: Malignant tumors in the prostate gland can be localized based on a standardized regional measurement of F FCH uptake. PET with F FCH is potentially useful for staging and localizing prostate cancer.     

Brain tumor imaging with synthesized f-fluorophenylalanine and positron emission tomography

Two patients with cerebral gliomas were studied with ¹⁸F-fluorophenylalanine, newly synthesized by the electrophilic substitution reaction, using positron emission tomography. The tracer accumulated markedly in the tumor lesion and delineated the extent of the lesion. This new tracer will be promising in the diagnosis of gliomas.     

Detection of aortic graft infection by fluorodeoxyglucose positron emission tomography: comparison with computed tomographic findings

OBJECTIVE: Radionuclide imaging with fluorodeoxyglucose (FDG) and positron emission tomography (PET) has been proposed for the identification of vascular graft infection; however, its accuracy has not been determined. We performed this prospective study to compare the usefulness of FDG-PET in the assessment of vascular graft infection relative to computed tomography (CT). METHODS: FDG-PET was performed for 33 consecutive patients with a suspected arterial prosthetic graft infection. The PET images were then assessed visually in terms of the density of uptake. In cases with positive uptake, the pattern of accumulation was also defined, such as focal or diffuse uptake. We compared the diagnostic efficiency of PET with contemporaneous CT in detection of infection of the arterial prosthetic graft. RESULTS: On the basis of the surgical, microbiological, and clinical follow-up findings, the aortic grafts were considered infected in 11 patients and not infected in 22 patients. Although the sensitivity of PET (91%) was higher than that of CT (64%), its specificity (64%) was lower than that of CT (86%). When focal uptake was set as the positive criterion in FDG, the specificity and positive predictive value of PET for the diagnosis of aortic graft infection improved significantly to 95% (P < .05 for both). CONCLUSIONS: Although both techniques are useful in evaluation of patients with suspected aortic graft infection, using the characteristic FDG uptake pattern described previously as a diagnostic criterion made the efficacy of FDG superior to that of CT in the diagnostic assessment of patients with suspected aortic graft infection.     

Tenosynovial giant cell tumor of the thigh: positron emission tomography findings

Tenosynovial giant cell tumors (TGCTs) are pigmented villonodular proliferative lesions originating from the synovium, bursa, or joint. TGCTs tend to be locally aggressive, and there is a chance for multiple occurrences, which often lead to impairment of joint function. In this article, we report the case of a diffuse-type extra-articular TGCT found in the thigh of a 36-year-old woman. Surveillance F-18 fluorodeoxyglucose positron emission tomography detected increased activity within the left thigh. This activity was confirmed with magnetic resonance imaging and with surgical excision and histopathologic determination of the tumor. This patient's case suggests that TGCTs may be discovered and followed after resection with positron emission tomography.