Postoperative restaging: PET/CT impact on diagnosis and management

Purpose

The goal of this study was to assess the value of combined PET/CT in the restaging of suspected recurrent cancer and its impact on further management planning of the patients.

Patients and methods

Fourty-two patients with suspected recurrence due to new clinical, biochemical and radiologic findings were prospectively evaluated. PET/CT results were compared with PET and CT data. A final diagnosis of recurrence was confirmed by biopsy or by further clinical and radiologic work-up.

Results

Thirty nine out of 42 patients had recurrence and or distant metastases in 108 malignant sites. For the site-based analysis PET/CT showed 100% sensitivity, 80% specificity, 98% PPV, 100% NPV and 98% accuracy compared with 100%, 50%, 94%, 100% and 95%, respectively, for PET, and 87%, 50%, 94%, 28% and 83%, respectively, for CT. For the patient-based analysis, PET/CT showed 100% sensitivity, 75% specificity, 97% PPV, 100% NPV and 98% accuracy compared with 100%, 50%, 92%, 100% and 93%, respectively for PET and 86%, 75%, 97%, 38% and 86%, respectively for CT. PET/CT results changed the management of 90% of patients.

Conclusion

PET/CT provides accurate restaging of suspected recurrent cancer with a significant clinical impact on further management planning.     

Accuracy of 18F-FDG PET/CT in detection and restaging of recurrent ovarian cancer

Purpose

To estimate the accuracy of 18FDG PET/CT in detection of recurrent cancer ovary and to describe the localization of metastases for restaging.

Present and future of PET and PET/CT in gynaecologic malignancies

Objectives

To review the published data in literature on patients affected by gynaecological malignancies to establish the role of ¹⁸F-FDG positron emission tomography (PET) and PET/CT in comparison to conventional imaging (CI).

Materials and methods

All papers specifically addressed to the role of ¹⁸F-FDG PET and PET/CT in gynaecological malignancies published on PubMed/Medline, in abstracts from the principal international congresses, in the guidelines from national Societies that had appeared in literature until November 2009 were considered for the purpose of the present study.

Results and conclusions

The use of ¹⁸F-FDG PET, and even more of ¹⁸F-FDG PET/CT, is increasing in the follow up of patients with gynaecologic malignancies and suspected recurrent disease: there is evidence in the literature that ¹⁸F-FDG PET/CT has a higher sensitivity than CI in depicting occult metastatic spread. An interesting issue is represented by patients with ovarian cancer with an increase of the specific biomarker, CA-125, and negative/inconclusive findings at CI. The use of ¹⁸F-FDG PET in differential diagnosis and staging is more controversial, but there is some evidence that a baseline PET examination performed before commencing therapy, for staging purpose, is also useful to evaluate the response to chemoradiation treatment. In several papers it has been suggested a relevant role of ¹⁸F-FDG PET/CT in evaluating the entity of response to treatment and therefore to plan the subsequent therapeutic strategy.     

The diagnostic value of PET/CT in recurrence and distant metastasis in breast cancer patients and impact on disease free survival

Aim of work

To detect the diagnostic value of PET/CT in breast cancer patients. We compared the performance of PET/CT with that of conventional imaging in detection of recurrence and distant metastasis and evaluated the impact PET/CT results have on disease free survival.

Materials and methods

We retrospectively studied 50 patients with breast cancer with clinical suspicion of recurrent or metastatic lesion and who underwent PET/CT and conventional imaging procedures. The imaging results were retrospectively compared with histopathology and clinical follow-up as a reference standard.

Results

PET/CT detected distant metastases with a sensitivity of 97% and a specificity of 93%. In contrast, the sensitivity and specificity of combined conventional imaging procedures were 75% and 73%, respectively, disease-free survival was significantly shorter in the 34 M1-PET/CT patients than in the 14 M0-PET/CT patients (log-rank P = 0.002) also PET/CT detected recurrence in 1 patient with equivocal mammographic findings.

Conclusion

In breast cancer, PET/CT is superior to conventional imaging procedures for detection of recurrence, distant metastases and PET/CT can be used to improve prediction of the clinical outcome of breast cancer patients.     

Response assessment of colorectal liver metastases with contrast enhanced CT/18F-FDG PET

Purpose

Evaluate the diagnostic performance of contrast enhanced CT/PET (ceCT/PET) in the response assessment of patients with colorectal cancer liver metastases.

Methods

33 ce CT/PET studies of 19 patients with colorectal liver metastases were prospectively evaluated. All of them, 13 (68.4%) were males and 6 (31.6%) females. Mean age and range were 63 [42–78]. All patients were treated with neoadjuvant chemotherapy. In all cases post-therapy diagnostic confirmation of liver lesions was obtained. A ce CT PET/was obtained 1 h after the injection of 370 MBq of 18F-FDG.Metabolic and morphologic studies were evaluated by two blinded nuclear physicians and radiologists respectively to assess the location, size and suspected diagnosis of lesions (benign or malignant). A combined assessment of both techniques was performed.The final diagnosis was established by histopathology or clinical/radiological follow-up greater than 6 months.

Results

A total of 120 liver lesions were identified, 115 were malignant and 5 benign.From the malignant lesions, 105 were identified with the ceCT, 44 with the PET and 109 with ceCT/PET. All of the benign lesions were correctly classified with any of the three imaging techniques.The sensitivity of PET, ceCT and ceCT/PET were of 38%, 91% and 95% respectively and the specificity was 100% in all three of the diagnostic studies.

Conclusion

Administration of intravenous contrast in the PET/CT is mandatory to evaluate treatment response rate of liver metastases due to the limitations of isolated metabolic images in these cases.     

Diagnostic accuracy of 18F-FDG PET/CT for detection of suspected recurrence in patients with oesophageal carcinoma

Purpose

To evaluate the role of ¹⁸F-FDG PET/CT in the detection of recurrence in patients with oesophageal carcinoma, suspected clinically or following conventional investigations.

Methods

This was a retrospective study. Data from 180 patients (age 56.3?±?10.4 years; 126 men, 54 women) with histopathologically proven oesophageal carcinoma (squamous cell 115, adenocarcinoma 59, neuroendocrine carcinoma 4, small cell 1, poorly differentiated 1) who had undergone 227 ¹⁸F-FDG PET/CT studies for suspected recurrence were analysed. Recurrence was suspected clinically or following conventional investigations. PET/CT images were revaluated by two nuclear medicine physicians in consensus. Findings were grouped into local, nodal and distant recurrence. Results were compared to those from contrast-enhanced (CE) CT when available (109 patients). Clinical/imaging follow-up (minimum 6 months) with histopathology (when available) was taken as the reference standard.

Results

Of the 227 ¹⁸F-FDG PET/CT studies,166 were positive and 61 were negative for recurrent disease. PET/CT showed local recurrence in 134, nodal recurrence in 115 and distant recurrence in 47, with more than one site of recurrence in 34. The PET/CT findings were true-positive in 153 studies, true-negative in 54, false-positive in 13 and false-negative in 7. The sensitivity of ¹⁸F-FDG PET/CT was 96 %, the specificity was 81 %, the positive and negative predictive values were 92 % and 89 %, respectively, and the accuracy was 91 %. PET/CT showed similar accuracy in patients with squamous cell carcinoma and in those with adenocarcinoma (P?=?0.181).¹⁸F-FDG PET/CT was more specific than CECT (67 % vs. 21 %; P?<?0.0001). PET/CT was superior to CECT for the detection of nodal recurrence (P?<?0.0001), but not local recurrence (P?=?0.093) or distant metastases (P?=?0.441).

Conclusion

¹⁸F-FDG PET/CT shows high accuracy in the detection of suspected recurrence in patients with oesophageal carcinoma. It is more specific than and is superior to CECT in the detection of nodal recurrence.     

The clinical utility of FDG-PET/CT in follow up and restaging of breast cancer patients

Background

Early diagnosis and accurate staging of loco-regional and distant recurrence after treatment of breast cancer is decisive for further therapeutic planning. Our aim was to evaluate the role of FDG-PET/CT in the follow up and restaging of breast cancer patients.

Methods

We retrospectively evaluated 34 female patients with a history of breast cancer. Patients were referred for a PET/CT scan because of suspected recurrence (n = 15), whole body staging in already confirmed cases of recurrence (n = 5), follow up and reassurance in asymptomatic patients (n = 7), follow up after local ablative therapy of liver metastases (n = 5), follow up after treatment of bone metastases (n = 2). PET-CT findings were compared with the findings obtained by other imaging modalities, histopathology, together with clinical and imaging follow up for at least 6 months.

Results

The PET/CT was considered pathological in 21/34 patients. Incorrect interpretations of PET/CT images occurred in 3 patients (8.8%). PET/CT showed an overall diagnostic accuracy of 91.2% with a sensitivity of 90.5% and a specificity of 92.3%. The PPV and NPV were 95% and 85.7%, respectively.

Conclusion

FDG-PET/CT may play a substantial role in the restaging and follow up of patients with breast cancer showing high sensitivity and specificity.     

Usefulness of PET–CT in the assessment of suspected recurrent colorectal carcinoma

Purpose

To evaluate the usefulness of PET/CT in detecting recurrent colorectal carcinoma (CRCR) in patients subsequent to colonic resection or rectal amputation and to compare it with the PET part of integrated FDG-PET/CT.

Materials and methods

PET/CTs from 32 patients with suspected CRCR were studied. Histology, clinical follow-up and additional imaging served as the gold standard. The sensitivity, specificity, positive and negative predictive values (PPV, NPV), and accuracy of PET as well as integrated PET/CT were calculated and compared for each of (a) intra-abdominal extra-hepatic recurrences, (b) extra-abdominal and/or hepatic recurrences, and (c) any form of CRCR.

Results

PPV, sensitivity, NPV, specificity and accuracy of PET in detecting intra-abdominal extra-hepatic CRCR were, respectively, 85.7%, 85.7%, 88.9%, 88.9%, and 87.5% compared with 92.9%, 92.9%, 94.5%, 94.5%, and 93.8%, respectively, for PET/CT. The corresponding values for the detection of extra-abdominal and/or hepatic CRCR were 84.6%, 84.6%, 89.5%, 89.5%, and 87.5% for PET versus 100%, 92.3%, 95%, 100%, and 96.9% for PET/CT. For all forms of recurrence, the corresponding values for PET were 80%, 80%, 66.7%, 66.7%, and 75%, respectively, compared with 94.5%, 90%, 84.6%, 91.7%, and 90.6%, respectively, for PET/CT.

Conclusion

PET/CT enhances the accuracy and specificity of diagnosis of CRCRa. PET/CT grows to reach prominent roles for imaging and restaging of patients after colorectal carcinoma resection.     

Predictive role of post-treatment [18F]FDG PET/CT in patients with uterine cervical cancer

Objective

To evaluate the efficacy of post-treatment positron emission tomography (PET)/computed tomography (CT) for identification of tumor recurrence, and to determine whether [¹⁸F]fluorodeoxyglucose (FDG) uptake measured as the maximum standardized uptake value (SUV_max) has predictive role regarding survival in patients with uterine cervical cancer.

Methods

Medical records from 276 women with uterine cervical cancer who had post-treatment [¹⁸F]FDG PET/CT performed were retrospectively reviewed. Results of PET/CT scans were compared with histological or clinical examination.

Results

Ninety-five (34.4%) of the 276 patients had documented recurrence by either surgical biopsy or clinical and imaging follow-up. Median duration from treatment to PET/CT scan was 24 months (range, 6–307). The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of post-treatment PET/CT were 94.7%, 87.8%, 80.4%, 97%, and 90.2%, respectively. The PET/CT scan modified both the diagnostic or treatment plan in 67 patients (24.3%). Patients were divided into two groups according to cut-off SUV_max established on the basis of ROC analysis (<5.25 vs. ≥5.25), and there was a significant difference in OS between groups (p = 0.001). In addition, the 5-year progression-free survival (PFS) and OS rates of patients with a negative PET/CT scan for recurrence were significantly better than those with a positive PET/CT (98.62% vs. 17.83%, p < 0.0001 for PFS, 99.31% vs. 85.38%, p = 0.0015 for OS).

Conclusion

Post-treatment PET/CT scan is a sensitive and accurate surveillance modality, and provides prognostic information in uterine cervical cancer. Furthermore, it may allow individualization of patient care.     

18F-FDG PET, combined FDG-PET/CT and MRI for evaluation of bone marrow infiltration in staging of lymphoma: a systematic review and meta-analysis

Background and purpose

Evaluation of bone marrow infiltration is an essential step in the staging of lymphoma. The accuracy of ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET), combined ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) and magnetic resonance imaging (MRI) in diagnosing bone marrow involvement of lymphoma has never been systematically assessed, and the present systematic review was aimed at this issue.

Methods

MEDLINE, EMBASE, Cochrane library and some other databases, from January 1995 to July 2010, were searched for initial studies. All the studies published in English or Chinese relating to the diagnostic value of ¹⁸F-FDG PET, PET/CT and MRI for patients with bone marrow involvement of lymphoma were collected. We extracted data to calculate sensitivity, specificity, SROC curves and AUC and to test for heterogeneity. The statistic software called “Meta-Disc 1.4” was used for data analysis.

Result

In 32 included studies, PET/CT had the highest pooled sensitivity, 91.6% (95%CI: 85.1, 95.9) and highest pooled specificity, 90.3% (95%CI: 85.9, 93.7). PET/CT also had the highest pooled DOR, 68.89 (95%CI: 15.88, 298.92). The AUC of PET, PET/CT, and MRI were 0.9430, 0.9505 and 0.8764. There was heterogeneity among studies and no evidence of publication bias.

Conclusion

PET/CT was a highly sensitive and specific modality in diagnosing patients with bone marrow involvement in lymphoma. Compared with MRI and PET alone, PET/CT can play important roles in the staging of lymphoma.     

Evaluation of the efficiency of FDG PET/CT in detection and characterization of skeletal metastases

Background and purpose

Combined PET/CT using 18F-FDG is widely used in evaluation of various malignancies; in their initial staging and more efficiently in their follow up; hence, the importance of evaluation of its diagnostic role in the imaging of skeletal metastases. The purpose of this study is to evaluate precisely the efficiency of FDG PET/CT in detection and characterization of osseous metastatic lesions compared to isolated PET and CT in various malignancies.

Patients and methods

The study included 123 patients divided into seven groups of malignancies to whom PET/CT was done. In this study population, a detailed retrograde lesion based analysis was performed for a total of 1705 detected bone lesions on PET, CT and fused PET/CT images. Sensitivity, specificity, PPV and NPV of each modality were calculated. Semi-quantitative and ROC curve analysis of the lesions were performed to study the relationship between the lesion’s SUV and its corresponding morphologic pattern on CT and to set a reliable SUV_max cut-off value that can predict the presence of malignant lesion.

Results

The calculated fused PET/CT sensitivities and specificities in various malignancies ranged from 95.2% to 99.6% and 75% to 100%, respectively. The combined PET/CT has significantly improved the low CT sensitivity (especially in lymphoma) as well as both CT and PET specificities. Our ROC analysis suggested using SUV_max of 3 as a cut off value for malignant osseous lesions.

Conclusion

Fused PET/CT was highly efficient in evaluation of skeletal metastases with superior performance in: detection of early bone marrow infiltration not apparent on CT, resolution of metabolic activity before definite signs of complete healing on CT, detection of missed sclerotic metastases on PET due to their relatively low metabolic activity, detection of intra and extra osseous recurrence and differentiation of benign from malignant bone lesions.     

Negative F-2-fluorodeoxyglucose PET/CT predicts good cancer specific survival in patients with a suspicion of recurrent ovarian cancer

Aim

The aim of the present study was to investigate the diagnostic and prognostic value of combined ¹⁸F-2-fluorodeoxyglucose positron emission tomography and contrast enhanced X-ray computed tomography (FDG-PET/CT) in women with a suspicion of recurrent ovarian cancer.

Patients and methods

We retrospectively reviewed 48 patients with a suspicion of recurrent ovarian cancer who were referred to our department for combined FDG-PET/CT.

Results

Median follow-up was 25 months. 38/48 (79%) patients showed pathological findings on PET/CT. 17/48 (35%) of patients died of ovarian cancer. One FDG-PET/CT was false positive and one was false negative, leading to a sensitivity and positive predictive value of 97% and a specificity and negative predictive value of 90%. 33/48 (69%) underwent a change in therapy following FDG-PET/CT. There was a significantly better survival in FDG-PET/CT negative than in positive patients (p = 0.04). In the FDG-PET/CT negative group no patients had died of ovarian cancer during follow-up. Remarkably, there was no difference in survival between patients who only had peritoneal metastases on FDG-PET/CT and those who also had extraperitoneal metastases (p = 0.71).

Conclusion

A negative FDG-PET/CT has a high negative predictive value for the presence of disease and, more importantly, is associated with a very good disease-specific survival rate.     

PET/CT scanning guided intensity-modulated radiotherapy in treatment of recurrent ovarian cancer

Objective

This study was undertaken to evaluate the clinical contribution of positron emission tomography using ¹⁸F-fluorodeoxyglucose and integrated computer tomography (FDG-PET/CT) guided intensity-modulated radiotherapy (IMRT) for treatment of recurrent ovarian cancer.

Materials and methods

Fifty-eight patients with recurrent ovarian cancer from 2003 to 2008 were retrospectively studied. In these patients, 28 received PET/CT guided IMRT (PET/CT–IMRT group), and 30 received CT guided IMRT (CT–IMRT group). Treatment plans, tumor response, toxicities and survival were evaluated.

Results

Changes in GTV delineation were found in 10 (35.7%) patients based on PET–CT information compared with CT data, due to the incorporation of additional lymph node metastases and extension of the metastasis tumor. PET/CT guided IMRT improved tumor response compared to CT–IMRT group (CR: 64.3% vs. 46.7%, P = 0.021; PR: 25.0% vs. 13.3%, P = 0.036). The 3-year overall survival was significantly higher in the PET–CT/IMRT group than control (34.1% vs. 13.2%, P = 0.014).

Conclusions

PET/CT guided IMRT in recurrent ovarian cancer patients improved the delineation of GTV and reduce the likelihood of geographic misses and therefore improve the clinical outcome.     

Retrocrural Lymph Node Metastasis Disclosed by 18F-FDG PET/CT: A Predictor of Supra-diaphragmatic Spread in Ovarian Cancer

Purpose

Retrocrural lymph nodes (RCLNs) communicate with retroperitoneal and posterior mediastinal LNs. It is possible that, when RCLNs are involved, supra-diaphragmatic extension will occur in abdomino-pelvic cancers. The authors investigated performance of ¹⁸F-FDG PET/CT to diagnose RCLN metastasis and whether RCLN metastases were associated with supra-diaphragmatic lymphatic metastases of ovarian cancer.

Materials and methods

Sixty-seven patients with stage IV ovarian cancer who had undergone ¹⁸F-FDG PET/CT were included in this retrospective study. Diagnostic performance of ¹⁸F-FDG PET/CT for RCLN metastasis was evaluated. Patients were divided into two groups by presence or absence of supra-diaphragmatic LN metastasis. The prevalences of RCLN metastasis between the two groups were compared and the odds ratio was calculated.

Results

Sensitivity and specificity of ¹⁸F-FDG PET/CT for RCLN metastasis were 96.3 and 100%, respectively. Of the 67 study subjects, 27 patients had RCLN metastases (40.3%). Fifty patients had supra-diaphragmatic LN metastases. ¹⁸F-FDG PET/CT showed 26 RCLN metastases in patients with supra-diaphragmatic LN metastases (54.5%), and only 1 in patients without supra-diaphragmatic LN metastasis (5.9%), and the difference between two groups was statistically significant (P < 0.05). The odds ratio that patients with RCLN metastasis would have supra-diaphragmatic LN metastasis was 17.3 (95% confidence interval = 2.1 to 140.9, P = 0.008).

Conclusion

Performance of ¹⁸F-FDG PET/CT to diagnose RCLN metastasis was excellent. RCLN metastasis revealed by ¹⁸F-FDG PET/CT was strongly associated with supra-diaphragmatic LN spread of ovarian cancer. Thus, RCLN metastasis could be used as a predictor of supra-diaphragmatic lymphatic metastasis of ovarian cancer.     

Value of F-FDG PET/CT in the diagnosis of primary gastric cancer via stomach distension

Objective

To clarify the usefulness of ¹⁸F-FDG PET/CT for detecting primary gastric cancer via gastric distention using a mixture of milk and Diatrizoate Meglumine.

Materials and methods

A total of 68 patients (male: 47, female: 21; age: 41–87 years) suspected of gastric carcinoma underwent ¹⁸F-FDG PET/CT imaging. After whole-body PET/CT imaging in a fasting state, the patients drank a measured amount of milk with Diatrizoate Meglumine. Local gastric district PET/CT imaging was performed 30 min later. The imaging was analyzed by semi-quantitative analysis, standardized uptake value (SUV) of the primary tumor was measured in a region of interest. The diagnosis results were confirmed by gastroscopy, pathology, and follow-up results.

Results

Of the 68 patients, 56 malignant gastric neoplasm patients (male: 37, female: 19) were conformed. The sensitivity, specificity, positive predictive value and negative predictive value of fasting whole-body PET/CT imaging for a primary malignant tumor were 92.9%, 75.0%, 94.5%, and 69.0%, respectively. The values for distension with a mixture of milk and Diatrizoate Meglumine were 91.1%, 91.7%, 98.1%, and 68.8%, respectively. The area under the curve was 0.919 ± 0.033 and 0.883 ± 0.066 for the diagnosis of gastric cancer with SUV_max in a fasting state and after intake of mixture respectively, the differences were not statistically significant (P = 0.359). Using gastric distension with a mixture of milk and Diatrizoate Meglumine, the mean ratio of the lesion's SUV_max to the adjacent gastric wall SUV_max increased significantly from 3.30 ± 3.05 to 13.50 ± 15.05, which was statistically significant (P < 0.001).

Conclusions

¹⁸F-FDG PET/CT imaging is highly accurate for the diagnosis of primary gastric carcinoma. Gastric distention can display the lesions more clearly, however, it cannot significantly improve diagnostic accuracy.     

Computer tomography, magnetic resonance imaging, and positron emission tomography or positron emission tomography/computer tomography for detection of metastatic lymph nodes in patients with ovarian cancer: a meta-analysis

Objectives

To compare the diagnostic performances of computed tomography (CT), magnetic resonance (MR) imaging, and positron emission tomography (PET or PET/CT) for detection of metastatic lymph nodes in patients with ovarian cancer.

Methods

Relevant studies were identified with MEDLINE and EMBASE from January 1990 to July 2010. We estimated the weighted summary sensitivities, specificities, OR (odds ratio), and summary receiver operating characteristic (sROC) curves of each imaging technique and conducted pair-wise comparisons using the two-sample Z-test. Meta-regression, subgroup analysis, and funnel plots were also performed to explain the between-study heterogeneity.

Results

Eighteen eligible studies were included, with a total of 882 patients. PET or PET/CT was a more accurate modality (sensitivity, 73.2%; specificity, 96.7%; OR [odds ratio], 90.32). No significant difference was detected between CT (sensitivity, 42.6%; specificity, 95.0%; OR, 19.87) and MR imaging (sensitivity, 54.7%; specificity, 88.3%; OR, 12.38). Meta-regression analyses and subgroup analyses revealed no statistical difference. Funnel plots with marked asymmetry suggested a publication bias.

Conclusion

FDG-PET or FDG-PET/CT is more accurate than CT and MR imaging in the detection of lymph node metastasis in patients with ovarian cancer.     

Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT scans for diagnosing ovarian cancer recurrence

Objective

To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated ¹⁸F-fluorodeoxyglucose (FDG)-PET/CT studies for restaging of ovarian cancer.

Materials and methods

One hundred and twenty women who had undergone treatment for ovarian cancer underwent a conventional PET/CT scans with ldCT, and then ceCT. Two observers interpreted and decided in consensus on the PET/ldCT and PET/ceCT images by a 3-point scale (N: negative, E: equivocal, P: positive) per patient and lesion site. Final diagnoses were obtained by histopathological examinations, or clinical follow-up for at least 6 months.

Results

Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/ceCT was 86.9% (40/46), 95.9% (71/74), and 92.5% (111/120), respectively, whereas those of PET/ldCT were 78.3% (36/46), 95.0% (70/74), and 88.3% (106/120), respectively. All sensitivity, specificity, and accuracy significantly differed between two methods (McNemar test, p < 0.0005, p = 0.023, and p < 0.0001, respectively). The scales of detecting 104 recurrent lesion sites were N:14, E:6, P:84 for PET/ceCT, and N:15, E:17, P:72 for PET/ldCT, respectively. Eleven equivocal and one negative regions by PET/ldCT were correctly interpreted as positive by PET/ceCT.

Conclusion

PET/ceCT is a more accurate imaging modality with higher confidence for assessing ovarian cancer recurrence than PET/ldCT.     

Prognostic value of preoperative intratumoral FDG uptake heterogeneity in patients with epithelial ovarian cancer

Objectives

To investigate the prognostic value of intratumoral FDG uptake heterogeneity (IFH) derived from PET/CT in patients with epithelial ovarian cancer (EOC).

Methods

We retrospectively reviewed patients with pathologically proven epithelial ovarian cancer who underwent preoperative ¹⁸F-FDG PET/CT scans. PET/CT parameters such as maximum and average standardized uptake values (SUV_max and SUV_avg), sum of all metabolic tumour volume (MTV), cumulative total lesion glycolysis (TLG) and IFH were assessed. Regression analyses were used to identify clinicopathological and imaging variables associated with disease-free survival (DFS).

Results

Clinicopathological data were reviewed for 61 eligible patients. The median duration of DFS was 13 months (range, 6–26 months), and 18 (29.5 %) patients experienced recurrence. High IFH values were associated with tumour recurrence (P?=?0.005, hazard ratio 4.504, 95 % CI 1.572–12.902). The Kaplan-Meier survival graphs showed that DFS significantly differed in groups categorized based on IFH (P?=?0.002, log-rank test). Moreover, there were significant differences in DFS (P?=?0.009) and IFH (P?=?0.040) between patients with and without recurrence.

Conclusions

Preoperative IFH measured by ¹⁸F-FDG PET/CT was significantly associated with EOC recurrence. FDG-based heterogeneity could be a useful and potential predicator of EOC recurrence before treatment.

Key Points

? Preoperative IFH was significantly associated with recurrence of EOC ? Disease-free survival significantly differed in groups categorized by IFH ? FDG-based heterogeneity could be a potential predicator of EOC recurrence before treatment

     

Diagnostic accuracy of 18F-FDG PET/CT for detecting recurrence in patients with primary skeletal Ewing sarcoma

Purpose

To evaluate the diagnostic accuracy of ¹⁸F-FDG PET/CT for detecting recurrence in patients with primary skeletal Ewing sarcoma.

Methods

We retrospectively analysed data from 53 patients (age 20.1?±?10.5 years, 39 male) who had undergone 71 ¹⁸F-FDG PET/CT studies for suspected recurrence (52 studies) or for routine follow-up (19 studies) after primary therapy of skeletal Ewing sarcoma. ¹⁸F-FDG PET/CT studies were evaluated qualitatively and quantitatively (maximum standardized uptake value, SUVmax) by two nuclear medicine physicians in consensus. Sensitivity, specificity, predictive values and accuracy were calculated on per study basis. Clinical/imaging follow-up (minimum 6 months) and/or histopathology (when available) were taken as the reference standard.

Results

Of the total of 71 ¹⁸F-FDG PET/CT studies, 42 (59.1 %) were positive for recurrence and 29 (40.9 %) were negative for recurrence. Local recurrence was most common (38 studies) followed by bone metastasis (9 studies), and node and lung metastasis (2 studies each). Of the 71 studies, 38 were true-positive, 27 were true-negative, 4 were false-positive and 2 were false-negative. Overall per study based sensitivity was 95 %, specificity was 87 %, PPV was 90 %, NPV was 93 % and accuracy was 91.5 %. No significant difference was found in the accuracy of PET/CT between the suspected recurrence group and the routine follow-up group (94 % vs. 84 %; P?=?0.390). Overall mean lesion SUVmax was 7.8?±?4.1 (range 1.9–17.2). No site-based difference was found in SUVmax.

Conclusion

¹⁸F-FDG PET/CT demonstrates high diagnostic accuracy for detecting recurrence in patients with primary skeletal Ewing sarcoma, when it is suspected (clinically or on imaging) or during routine follow-up.     

Evaluation of suspected local recurrence in head and neck cancer: a comparison between PET and PET/CT for biopsy proven lesions

Background

¹⁸F-FDG PET has a high accuracy for re-staging of head and neck cancer. The purpose of this study was to determine whether the diagnostic accuracy can be further improved with integrated PET/CT.

Materials and methods

Forty-nine patients with a mean age of 59 ± 18 years were studied retrospectively. Histo-pathological verification was available either from complete tumor resection with or without lymph node dissection (n = 27) or direct endoscopic biopsy (n = 16) or ultrasound guided biopsy (n = 6). Two reviewers blinded to the pathological findings read all PET images in consensus. An experienced radiologist was added for the interpretation of the PET/CT images.

Results

Tissue verification was available for 110 lesions in 49 patients. Sixty-seven lesions (61%) were biopsy positive and 43 (39%) were negative for malignant disease. PET and PET/CT showed an overall accuracy for cancer detection of 84 and 88% (p = 0.06), respectively. Sensitivity and specificity for PET were 78 and 93% versus 84 (p = NS) and 95% (p = NS) with PET/CT. A patient-by-patient analysis yielded a sensitivity, specificity and accuracy for PET of 80, 56 and 76%, compared to 88% (p = NS), 78% (p = NS) and 86% (p = 0.06) for PET/CT.

Conclusion

The results of this study indicate that PET/CT does not significantly improve the detection of recurrence of head and neck cancer. However, a trend towards improved accuracy was observed (p = 0.06).