Biomedical subjects

V J Lowe

Publications and source records attributed to V J Lowe.

32 records · Page 2Linked to original sources

PubMed1995

Detection of primary and recurrent lung cancer by means of F-18 fluorodeoxyglucose positron emission tomography (FDG PET).

Positron emission tomography (PET), with the glucose analog F-18 fluoro-deoxyglucose (FDG), takes advantage of the enhanced glucose uptake observed in neoplastic cells. We examined whether the detection of preferential FDG uptake with PET permits differentiation between benign and malignant focal pulmonary lesions in patients with suspected primary or recurrent lung cancer. Between November 1991 and September 1993, 100 patients with indeterminate focal pulmonary abnormalities including 16 patients who had previous lung resections for cancer were prospectively studied. Tissue diagnosis was obtained by transbronchial or percutaneous biopsy (n = 49) and open biopsy or resection (n = 35). Three patients underwent extended observation (> 2 years) alone. Excluded were 13 patients lacking firm pathologic diagnoses and less than 2-year follow-up. FDG activity in the lesion was expressed as a calculated standardized uptake ratio. Mean standardized uptake ratio (+/- standard deviation) was 6.6 (+/- 3.1) in 59 patients with cancer versus 2.0 (+/- 1.6) in 28 with benign disease (p = 0.0001; unpaired t test, two-sided). With a standardized uptake ratio > or = 2.5 used for detecting malignancy, sensitivity, specificity, and accuracy were 97% (57/59), 82% (23/28), and 92% (80/87), respectively. Notably, in patients evaluated for pulmonary abnormalities after lung resection for cancer, all chest recurrences were correctly identified. The exceptional sensitivity of FDG PET demonstrates that malignant pulmonary lesions preferentially accumulate FDG, which results in a standardized uptake ratio > or = 2.5. PET may be useful for distinguishing recurrent tumor from postoperative, or postradiation, changes. If performed in all patients before open biopsy, PET increases the diagnostic yield by reducing the number of patients who have benign lesions at operation. Moreover, by lowering expenditures for hospitalization and other diagnostic procedures, FDG PET may significantly reduce health care costs.

Adenocarcinoma↗

PubMed1995

Ventilation/perfusion lung scan probability category distributions in university and community hospitals.

The criteria used in the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study for the interpretation of ventilation/perfusion scans are widely used and the probability of pulmonary embolism is determined from these criteria. The prevalence of pulmonary embolism in the PIOPED study was 33%. To investigate the similarity of patient populations who have ventilation/perfusion scans at one of the medical centers that participated in the PIOPED study and a small community hospital, the authors evaluated the probability category distributions of lung scans at the two institutions. They retrospectively interpreted 54 and 49 ventilation/perfusion lung scans selected from January, 1991, to June, 1992, at Duke University Medical Center and at Central Carolina Hospital, respectively. Studies were interpreted according to the PIOPED criteria. The percentage of studies assigned to each category at Duke University Medical Center and Central Carolina Hospital were 17% and 27% normal or very low probability, 31% and 59% low probability, 39% and 10% intermediate probability, and 13% and 4% high probability, respectively. The different distribution of probability categories between university and community hospitals suggests that the prevalence of disease may also be different. The post-test probability of pulmonary embolism is related to the prevalence of disease and the sensitivity and specificity of the ventilation/perfusion scan. Because these variables may differ in community hospital settings, the post-test probability of pulmonary embolism as determined by data from the PIOPED study should only be used in institutions with similar populations. Clinical management based upon the results of the PIOPED study may not be applicable to patients who have ventilation/perfusion scans performed in a community hospital.

Hospitals, Community↗

PubMed1995

Thoracic nodal staging with PET imaging with 18FDG in patients with bronchogenic carcinoma.

PURPOSE: To assess the role of positron emission tomographic (PET) imaging with 18-fluoro-2-deoxyglucose (18FDG) in detecting thoracic lymph node metastases in patients with bronchogenic carcinoma. MATERIALS AND METHODS: Over a 2-year period, any patient presenting to our institution with newly diagnosed bronchogenic carcinoma who was to have thoracic nodes sampled was considered eligible. All PET studies were performed prior to nodal sampling and areas of increased uptake were mapped according to the American Thoracic Society classification. Studies were correlated with CT and pathology. Sensitivity and specificity for predicting nodal metastases was calculated. RESULTS: Forty-two patients had 62 nodal stations (40 hilar/lobar, 22 mediastinal) sampled. The sensitivity and specificity for hilar/lobar lymph node station metastases using PET imaging was 73% and 76%, respectively. With CT, the sensitivity and specificity were 27% and 86%. The sensitivity and specificity using PET imaging for mediastinal node station metastases was 92% and 100%, respectively, while with CT the figures were 58% and 80%. The sensitivity and specificity for combined thoracic nodal station metastases using PET imaging was 83% and 82%, respectively, while with CT it was 43% and 85%. There was a strong statistical relationship between positive PET imaging and lymph node abnormalities. CONCLUSIONS: 18FDG-PET imaging is accurate in detecting thoracic lymph node metastases in patients with bronchogenic carcinoma. Normal results of PET studies virtually preclude the need for mediastinal nodal sampling prior to surgery, whereas abnormal results of studies most likely represent mediastinal metastases. Treatment can be based on the extent of disease suggested by PET imaging.

Adult↗

PubMed1995

Optimum scanning protocol for FDG-PET evaluation of pulmonary malignancy.

UNLABELLED: FDG-PET can differentiate benign from malignant focal pulmonary opacities. We performed dynamic FDG-PET studies to determine the optimum time for emission data acquisition. METHODS: Patients with focal pulmonary abnormalities demonstrated by biopsy to be malignant (n = 10) or benign (n = 4) were evaluated with dynamic FDG-PET. Dynamic PET data were acquired as sequential 5-min images for 2.5 hr. Radioactivity concentration measurements of the focal abnormality, a similar area in the opposite lung, and both lungs in the field of view were made throughout the period of acquisition. Standardized uptake ratios (SUR) of the lesions were calculated. SUR data and lesion-to-background ratios were plotted. The time that the SUR provided the maximum separation between benign and malignant masses after FDG administration was determined. RESULTS: The SUR values provided the greatest separation between benign and malignant abnormalities beginning at 50 min and no advantage was identified in imaging later. Achievement of a 4:1 lesion-to-background ratio occurred by 50 min in malignant lesions. CONCLUSION: The acquisition of the emission data used in the evaluation of pulmonary malignancy should begin approximately 50 min after FDG administration.

Deoxyglucose↗

PubMed1994

Persistent or recurrent bronchogenic carcinoma: detection with PET and 2-[F-18]-2-deoxy-D-glucose.

PURPOSE: To assess positron emission tomography (PET) with 2-[fluorine-18]-2-deoxy-D-glucose (FDG) in the differentiation of recurrent bronchogenic carcinoma from fibrosis after therapy. MATERIALS AND METHODS: Any patient treated for bronchogenic carcinoma who had a residual chest radiographic abnormality was eligible. Forty-three patients (mean age, 63.5 years) participated. Chest radiographs and thoracic computed tomographic scans helped localize the abnormality prior to PET. Semiquantitative analysis was performed on FDG PET images with calculated standardized uptake ratios (SURs). Sensitivity, specificity, and confidence intervals for recurrent disease were determined. RESULTS: Thirty-five patients had recurrent or persistent tumor (median SUR, 7.6; range, 1.9-18.7). Eight patients had fibrosis but no evidence of disease (SUR, 1.6; range, 0.6-2.4). The sensitivity for detecting recurrent tumor (SUR > 2.5) was 97.1%, and specificity was 100%. The SUR for recurrent tumor was statistically significantly higher than for fibrosis (P = .0001). CONCLUSION: FDG PET accurately helps differentiate recurrent bronchogenic carcinoma from fibrosis.

Carcinoma, Bronchogenic↗

PubMed1994

Semiquantitative and visual analysis of FDG-PET images in pulmonary abnormalities.

UNLABELLED: FDG PET images of the thorax can be analyzed semiquantitatively using standardized uptake ratios (SUR) or activity ratios between abnormal and normal tissue, or qualitatively by visual comparison of the abnormality to normal structures. Standardized uptake ratio evaluation of FDG PET images has been shown to accurately differentiate benign from malignant focal pulmonary abnormalities. The accuracy of activity ratios and visual analysis have not been evaluated. We therefore prospectively analyzed FDG PET images in patients with pulmonary abnormalities to evaluate differences in analytic schemes. METHODS: We evaluated 107 patients with an indeterminate focal abnormality on chest radiograph or CT with FDG PET between November 1991 and March 1993. The PET studies were evaluated using SUR, activity ratios and visual analysis. Activity ratios of maximum activity/cc and average activity/cc between regions of interest (ROIs) in abnormalities and normal lung on the contralateral side were calculated. Visual interpretations were graded on a five-point scale of two observers' confidence of malignancy. FDG uptake in the abnormality was also visually graded in comparison to mediastinal activity. Receiver-operating characteristic (ROC) curve areas were generated for the SUR data, activity ratios and visual analysis. RESULTS: Of 88 patients in which a conclusive diagnosis was made, 61 (69%) patients had malignancy and 27 (31%) patients had a benign process. SUR, maximum activity ratio, average activity ratio and visual interpretation ROC curve areas were 0.96, 0.95, 0.92 and 0.96, respectively. CONCLUSIONS: SUR, activity ratios and visual evaluation are each equally accurate methods of FDG PET data analysis in differentiating malignant from benign focal pulmonary abnormalities.

Deoxyglucose↗

PubMed1994

Cerebral imaging of decompression injury patients with 18-F-2-fluoro-2-deoxyglucose positron emission tomography.

The objective assessment of the extent of cerebral insult and the effects of therapy in decompression injury patients has proven to be difficult by most imaging modalities. In this pilot study we evaluated the ability of 18-F-2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) to identify metabolic brain abnormalities in decompression injury patients. Twenty-two patients who were evaluated at our institution for decompression accidents were evaluated with FDG-PET. Four of the 22 patients had no neurologic symptoms and no neurologic findings on clinical exam at the time of the FDG-PET study. No statistically significant correlations were found between the presence of symptoms and the demonstration of abnormalities on the PET study and no statistically significant correlation was found between the location of the decompression injury and the demonstration of abnormalities on the PET study. We conclude that FDG-PET imaging of the brain cannot reliably identify cerebral abnormalities in patients with decompression injuries and would be of limited benefit for monitoring therapy in patients with decompression illness.

Adult↗

PubMed1993

Focal pulmonary abnormalities: evaluation with F-18 fluorodeoxyglucose PET scanning.

The authors assessed the role of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) in differentiation of benign from malignant focal pulmonary abnormalities seen on chest radiographs. Fifty-one patients underwent FDG PET scanning. Focal abnormalities at radiography included solitary pulmonary nodules (n = 38), pulmonary masses (n = 5), and poorly marginated infiltrates or opacities (n = 8). Proof of diagnosis was obtained by means of transbronchial biopsy (n = 21), open lung biopsy (n = 14), percutaneous needle biopsy (n = 14), or cytologic evaluation of sputum (n = 1). A nodule in one patient had been radiographically stable for at least 8 years. Quantitative analysis was performed by calculation of a standardized uptake ratio (SUR). Thirty-three malignant lesions had a mean SUR (+/- 1 standard deviation) of 6.5 +/- 2.9. Eighteen benign lesions had a mean SUR of 1.7 +/- 1.2. For a benign lesion with SUR of 2.5 or less, specificity of FDG PET was 100%, while sensitivity was 89%. These results suggest that FDG PET is accurate in differentiation of benign from malignant focal pulmonary abnormalities.

Adult↗

PubMed1993

Cardiac phantom evaluation of simultaneously acquired dual-isotope rest thallium-201/stress technetium-99m SPECT images.

Simultaneously acquired dual-isotope 201Tl/99mTc SPECT studies were performed using cardiac and thoracic phantoms to evaluate the dual-isotope myocardial perfusion technique. Cardiac phantom images representing infarction, viable myocardium and various levels of ischemia were analyzed. Studies with and without attenuating media were performed, and myocardium-to-defect count ratios and defect sizes from dual-isotope SPECT images were compared to myocardium-to-defect count ratios and defect sizes from single-isotope (201Tl and 99mTc) SPECT images. Dual-isotope studies also were interpreted qualitatively. Studies with background activity simulating clinical conditions were performed and interpreted qualitatively. Myocardium-to-defect count ratios from both 99mTc and 201Tl were similar in single-isotope and dual-isotope SPECT images. Thallium-201 and 99mTc defect sizes were decreased slightly (mean +/- s.d., 1.0 +/- 1.7 cc for 201Tl and 0.7 +/- 1.0 cc for 99mTc) on dual studies when compared to single studies but were not statistically significant. Dual-isotope image simulations of normal, ischemic and infarcted and viable myocardium were correctly identified by experienced clinicians in 95% of the cases (21/22). Simultaneous dual-isotope 201Tl/99mTc SPECT imaging of cardiac phantoms produced images that had similar myocardium-to-defect count ratios to those produced using single-isotope techniques and were correctly evaluated on qualitative analysis. Changes in defect size related to dual-isotope imaging were minimal and not qualitatively important.

Evaluation Studies as Topic↗

PubMed1990

Electron transfer reactions of metalloproteins at peptide-modified gold electrodes.

The electron transfer reactions of four small redox proteins, cytochrome c. ferredoxin, plastocyanin and azurin, have been investigated at novel peptide-modified gold electrodes. These proved to be effective and selective in facilitating electron transfer. Good, quasi-reversible electron transfer was achieved selectively at different peptide-protein configurations by changing the pH or the ionic strength of the solution. The use of peptides as promoters for protein electrochemistry opens up the possibility of designing very specific electrode surfaces for larger molecules like enzymes.

Azurin↗

PubMedDate not supplied

Local recurrence of rectal cancer: evaluation with F-18 fluorodeoxyglucose PET imaging.

BACKGROUND: Positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) is a useful technique for detection of malignancy. The purpose of this study was to determine if FDG-PET scanning using visual and quantitative analyses can identify patients with recurrent colorectal tumor following abdominoperineal resection. METHODS: Eighteen patients were evaluated for possible local recurrence of rectal carcinoma following abdominoperineal resection. The clinical presentation included rising carcinoembryonic antigen levels (n = 5), increasing size of a presacral mass on computed tomography or magnetic resonance (n = 13), or local symptoms (n = 3). Axial PET images of the pelvis were obtained following an injection of 10 mCi of FDG prior to biopsy. Quantitative analysis was performed by calculation of a standardized uptake ratio (SUR), and the images were interpreted by two radiologists in consensus. FDG-PET findings were correlated with histological or cytological findings and with the clinical outcome. RESULTS: Recurrent malignancy was confirmed in 13 patients by surgery (n = 8) or percutaneous biopsy (n = 5). Benign lesions were confirmed in five patients by surgery (n = 1), biopsy (n = 3), or clinical follow up (n = 1). Visual analysis of the FDG-PET data had a sensitivity of 92.3% (12/13) for recurrent disease (95% confidence limits; 63.9%, 99.8%) and a specificity of 80% (4/5; 95% confidence limits; 28.3%, 99.4%). SUR values were significantly higher in malignant lesions (range = 2.92-19.74, mean = 6.89) than in benign ones (range = 1.40-3.47, mean = 1.96; p = 0.002). CONCLUSION: FDG-PET is an accurate technique for detection of locally recurrent colorectal carcinoma. Visual analysis is equivalent to quantitative analysis for detection of disease.

Deoxyglucose↗

PubMedDate not supplied

Correlation of fine needle aspiration biopsy and fluoride-18 fluorodeoxyglucose positron emission tomography in the assessment of locally recurrent and metastatic head and neck neoplasia.

OBJECTIVE: Patients with primary head and neck neoplasia can present during follow-up with suspected recurrence, and both fine needle aspiration biopsy (FNAB) and fluoride-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scan are available methodologies for evaluating these patients. Our objective was to retrospectively correlate patients who underwent both FNAB and FDG-PET scan in order to assess the possibility of recurrent neoplasia. STUDY DESIGN: The cytopathology files at Saint Louis University Health Sciences Center were retrospectively searched for patients with known primary head and neck malignancies beginning in 1995. Suspected recurrence and local metastases evaluated by both FNAB and FDG-PET scan were correlated. RESULTS: Twenty-eight patients received a combined total of 37 FNABs with concurrent FDG-PET scans. The majority of patients had primary oropharyngeal squamous cell carcinoma with intermixed, single cases of other primary head and neck neoplasms. Thirty of the 32 aspirates with recurrent or locally metastatic disease had combined positive findings by both FNAB and FDG-PET scan, yielding a sensitivity of 94%. One nonspecific and one negative FDG-PET scan came from a patient who had disease confirmed by FNAB. Five patients had negative findings by both methods that were supported by the subsequent clinical course. CONCLUSION: FNAB can provide confirmatory evidence of disease in a clinically suspicious abnormality with nonspecific FDG-PET results. FNAB and FDG-PET are highly sensitive for tumors in cases of clinically suspected recurrence and locally metastatic disease.

Biopsy, Needle↗

PubMedDate not supplied

Triple-technique (MR imaging, single-photon emission CT, and CT) coregistration for image-guided surgical evaluation of patients with intractable epilepsy.

Ictal and interictal single-photon emission CT (SPECT) play an increasingly important role in the surgical evaluation of patients with epilepsy. We present a method of coregistration of MR, SPECT, and CT images to correlate structural data (MR imaging), blood flow changes (SPECT), and location of subdural electrodes (CT) for patients undergoing image-guided surgical treatment of epilepsy. MR-SPECT root mean square (rms) mismatch distances were 2.1 to 2.5 mm, and MR-CT rms mismatch distances were 1.0 to 4.5 mm. Coregistration assisted in image-guided placement of subdural electrodes and in surgical resection of the suspected epileptogenic focus.

Adolescent↗

PubMedDate not supplied

Overexpression of MPS antigens by squamous cell carcinomas of the head and neck: immunohistochemical and serological correlation with FDG positron emission tomography.

Survival from advanced primary or recurrent Squamous Cell Carcinoma (SCC) of the head and neck (H&N) is poor. More accurate detection of primary tumors and recurrence may provide ways to improve survival. No standard serum tumor marker is routinely used for surveillance of SCC-H&N. In this paper, we evaluated the performance characteristics of the MPS-H tumor marker test for the quantitative measurement of "MPS-H" heat-generated immunoreactive proteins and assessed the clinical utility of this marker in the detection and monitoring of SCC-H&N. In approximately 92% of the subjects having no evidence of SCC-H&N, the MPS-H levels were lower than 15 ng/mL. In 76% of patients having SCC-H&N at various stages (T1-T4), the MPS-H level was > 15 ng/mL (range: 20-200 ng/mL). In addition, we found a statistically significant correlation between PET positive cases and high MPS-H serum levels in SCC-H&N patients with recurrent disease. These results suggest that MPS-H may provide an initial screening test that would allow for selective PET imaging in these patients. Furthermore, we found that there was greater expression of MPS-1 in tumors of higher histological grades. Thus, in tumors with more histological aggressiveness there is more MPS-1, indicating the potential usefulness of this marker in prognosis for SSC-H&N. Considering the immunohistochemical, serological, and FDG-PET data presented here, and the compelling need to expedite the early diagnosis of primary and recurrent epithelial malignancies of the head and neck, we are further evaluating the system of MPS antigens in a large patient population as a tool for the early serologic and histologic diagnosis of SCC-H&N.

Adult↗