Glucose Positron Emission Tomography-computed Tomography Research Articles

The Prognostic Role of Maximum Standardized Uptake Value of 18 F-FlouroDeoxy Glucose Positron Emission Tomography-Computed Tomography in Head and Neck Cancer Patients Undergoing Chemoradiotherapy.

Aims and Objectives:This retrospective study aims at correlating the pre- and post-therapy maximal standardized uptake values (SUVmax) of the whole-body 18-flourodeoxy glucose positron emission tomography (FDG-PET) scan with tumor response in patients with head and neck squamous cell cancer undergoing chemoradiotherapy.Materials and Methods:Data for this retrospective study were taken from the clinical records of 20 evaluable head and neck cancer patients who had availed treatment and evaluation at our institute during the previous year (March 2017–April 2018). All these above-mentioned patients had undergone chemoradiation at our center for locally advanced squamous cell carcinoma of the head and neck and had undergone pre- and post-therapy whole-body FDG PET scan. The posttherapy PET-computed tomography (CT) was advised after 8 weeks’ postcompletion of therapy. During the PET CT scan, images were acquired 1 h after injection of FDG. Pre- and post-therapy SUVmax were recorded and correlated with immediate treatment response.Results:The mean pretherapy SUVMax of the primary tumor was 10.27 ranging from 4.5 to 26.17. The mean pretherapy SUVMax of the node was 5.34 ranging from 0 to 17.9. The mean time of recording the posttherapy SUVMax was 3 months (range 2–5 months). The mean posttherapy SUVMax of the primary tumor was 1.05 ranging from complete metabolic response to 6.4. The mean posttherapy SUVMax of the node was 0.7 ranging from complete metabolic response to 5.43. The statistical analysis based on Wilcoxon–Signed Rank test revealed a statistically significant difference in the pre- and post-therapy SUVmax values for both primary tumor (P < 0.001) and regional node (P = 0.001). Majority of patients (n = 15) showed clinical remission; however, five patients had progressive disease at the time of evaluation.Conclusion:Although the retrospective study revealed that complete responders had a statistically significant reduction in the posttherapy SUVmax in comparison to the pretherapy SUVmax it failed to identify a cutoff value for pretherapy SUVmax which could predict the probable outcome of therapy. In view of the same further prospective studies need to be conducted with larger patient numbers including various other tumor metabolic markers for greater clarity.

18-F flourodeoxy glucose positron emission tomography-computed tomography imaging: A viable alternative to three phase bone scan in evaluating diabetic foot complications?

Background:This paper is based on the initial findings from a prospective ongoing study to evaluate the efficacy of flourodeoxy glucose positron emission tomography-computed tomography (FDG-PET CT) in diabetic foot evaluation.Objective:The aim was to compare the diagnostic accuracies of three phase bone scan (TPBS) and FDG PET-CT (FDG-PET) in diabetic foot evaluation.Methods:Seventy-nine patients with complicated diabetic foot (osteomyelitis/cellulitis, Charcot's neuropathy) were prospectively investigated. TPBS (15 mci methylene di phosphonate [MDP] intravenous [IV]), followed by FDG-PET (5 mci IV) within 5 days were performed in all patients. Based on referral indication, patients grouped into Group I, n = 36, (?osteomyelitis/cellulitis) and Group II, n = 43 (?Charcot's neuropathy). Interpretation was based on intensity, extent, pattern of MDP and FDG uptake (standardized uptake value) along with CT correlation. Findings were compared with final diagnostic outcome based on bone/soft tissue culture in Group I and clinical, radiological or scintigraphic followup in Group II. Results: Group I: For diagnosing osteomyelitis, TP: TN: FP: FN were 14:5:2:2 by FDG PET and 13:02:05:03 by TPBS respectively. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of FDG-PET were 87.5%, 71%, 87.5% and 71% and 81.25%, 28.5%, 72% and 40% for TPBS, respectively. Group II: charcot's: cellulitis: Normal were 22:14:7 by FDG PET and 32:5:6 by TPBS, respectively.Conclusion:Flourodeoxy glucose PET-CT has a higher specificity and NPV than TPBS in diagnosing pedal osteomyelitis. TPBS, being highly sensitive is more useful than FDG-PET in detecting Charcot's neuropathy.

Stomach metastasis of breast carcinoma mimicking primary gastric neoplasm on fluorodeoxy glucose-positron emission tomography-computed tomography

We present fluorodeoxy glucose positron emission tomography–computed tomography (FDG-PET/CT) findings in a case of breast carcinoma. The PET/CT findings in this case were suspicious of second primary neoplasm in the stomach. However, on endoscopic biopsy, the lesion was found to be stomach metastasis of breast carcinoma with estrogen receptor positivity. Stomach is a rare site of breast carcinoma metastasis. Our case suggests that it is difficult to distinguish a stomach metastasis of breast cancer from a primary gastric cancer on the basis of clinical and imaging features. However, this differential diagnosis must be kept in mind and it is important to make such distinction because of its implications on patient management.

Reply to Bertolaccini et al.

We thank Bertolaccini et al. [1] for their interest in our paper [2] and appreciate the opportunity to reply. To begin with, we would like to point out some misunderstandings with regard to our paper. In our analysis, we divided 58 patients with thymic epithelial tumours into three groups according to a simplified histological classification: low-risk thymomas (Types A, AB and B1, n = 23), high-risk thymomas (Types B2 and B3, n = 21) and thymic carcinomas (n = 14). The maximum standardized uptake value (SUVmax) of the thymic carcinomas was significantly higher than those of the low-risk and high-risk thymomas (P < 0.001, respectively). No significant differences were observed between the low-risk thymomas and the high-risk thymomas (P = 0.204). In addition, as shown in Figure 3 in our article, the SUVmax of the Stages III and IV thymomas showed a higher trend towards Stages I and II thymomas (P = 0.060). We excluded thymic carcinoma cases in this analysis because the majority of them were in advanced stages. Although no significant differences were observed between the low-risk and the high-risk thymomas, we suppose that significant differences might appear if the number of patients increases. We think that the large confidence interval in our box–whisker plot is due to the small number of cases. As often said, SUVmax is a very nonuniform value between institutions. It depends on the dose of radionucleotide that is given, the machine, the timing of scanning and the radiologist reading it and so on. Calculating the SUV tumour mediastinum (T/M) ratio is one of the methods to ensure the universality of SUVmax in [ F] fluoro-2-deoxy-D glucose positron emission tomography-computed tomography (F-FDG PET-CT) [1]. We cannot provide these data in our cohort, as they were not available in our previous cases. However, as other authors have demonstrated [3–5], there is little difference between the results of SUVmax T/M ratio and nonadjusted SUVmax. We believe that nonadjusted SUVmax in F-FDG PET-CT can play an important role in the differential diagnosis between thymomas and thymic carcinomas. The area under the curve in receiver-operating curve for the differential diagnosis between thymomas and thymic carcinomas was 0.951 in our cohort (data is not shown), a result that is considered to be quite good. We completely agree on the necessity of prospective studies with a larger number of patients, as thymic epithelial tumours are quite a rare disease. Discussions between not only thoracic surgeons, but also radiologists and pathologists are required to ensure the universality of radiological and pathological diagnoses.

Incidentally detected vesico inguinal hernia on fluoro-deoxy glucose positron emission tomography-computed tomography

Incidentally detected vesico inguinal hernia on fluoro-deoxy glucose positron emission tomography-computed tomography

Evaluation of mediastinal lymph nodes using 18 F-FDG PET-CT scan and its histopathologic correlation

AIMS AND OBJECTIVES:To determine the efficacy of integrated 18F-fluorodeoxy glucose positron emission tomography-computed tomography (18F-FDG PET-CT) in the evaluation and characterization of mediastinal lymph nodes into benign and malignant pathology.METHODS:Thirty-five patients with mediastinal lymphadenopathies without primary neoplastic or infective lung pathologies were included in the study. The lymph nodes were detected on contrast-enhanced CT scan of the chest. All patients underwent 18F-FDG PET-CT scan for evaluation of mediastinal lymph nodes. Results of PET-CT were compared with histopathology of the lymph nodes and sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated.STATISTICAL ANALYSIS:The data were collected prospectively and analyzed using (SPSS Inc., Chicago, IL) 11.5 software.RESULTS:Histopathology results in 35 patients revealed tuberculosis in 12, sarcoidosis in 8, and lymphoma in 15. Maximum standardized uptake value (SUVmax) of the benign lymph nodes ranged from 2.3 to 11.8 with a mean±standard deviation (SD) of 5.02±3.26. SUVmax of the malignant lymph nodes ranged from 2.4 to 34 with a mean±SD of 10.8±8.12. There was a statistically significant difference between benign and malignant pathology (P<0.0059). 18F-FDG PET-CT has sensitivity of 93% and specificity of 40% with SUVmax 2.5 as the cutoff. We found the optimal SUVmax cutoff to be 6.2 as determined by the receiver–operator characteristic curve. With 6.2 as cutoff, the sensitivity, specificity, and accuracy were 87%, 70%, and 77%, respectively.CONCLUSIONIn countries where tuberculosis and other granulomatous diseases are endemic, SUVmax cutoff value of 2.5 has low specificity. Increasing the cutoff value can improve the specificity, while maintaining an acceptable sensitivity.

Integrated FDG-PET-CT: its role in the assessment of bone and soft tissue tumors

The purpose of this study was to evaluate prospectively, whether integrated 2-deoxy-2-[(18)F]fluoro-D: -glucose positron emission tomography-computed tomography (FDG-PET-CT) is more accurate for determination musculoskeletal tumors compared with separate interpretation of CT and FDG-PET, because most of the current clinical data come from patients studied with PET. Eighty patients with newly diagnosed musculoskeletal tumors underwent FDG-PET-CT. CT, FDG-PET, and FDG-PET-CT were interpreted separately to determine the performance of each imaging modality. Assuming that equivocal lesions are benign, performance of diagnostic tests was as follows: sensitivity, specificity and accuracy for CT alone was 81, 84, 83%, for PET 71, 82, 76, and for PET-CT 80, 83 and 86%. Assuming that equivocal lesions are malignant, sensitivity, specificity, and accuracy for CT was 61, 100, 70%, for PET 69, 100, 79, and for PET-CT 69, 100 and 79%. Combined FDG-PET-CT reliably differentiates soft tissue and bone tumors from benign lesions. The value of the information provided by FDG-PET-CT for planning surgical procedures must be evaluated in further studies.