Related Articles

Background

Accurate evaluation of axillary lymph node (ALN) involvement is mandatory before treatment of primary breast cancer. The aim of this study is to compare preoperative diagnostic accuracy between positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (18F-FDG PET/CT) and axillary ultrasonography (AUS) for detecting ALN metastasis in patients having operable breast cancer, and to assess the clinical management of axillary 18F-FDG PET/CT for therapeutic indication of sentinel node biopsy (SNB) and preoperative systemic chemotherapy (PSC).

Methods

One hundred eighty-three patients with primary operable breast cancer were recruited. All patients underwent 18F-FDG PET/CT and AUS followed by SNB and/or ALN dissection (ALND). Using 18F-FDG PET/CT, we studied both a visual assessment of 18F-FDG uptake and standardized uptake value (SUV) for axillary staging.

Results

In a visual assessment of 18F-FDG PET/CT, the diagnostic accuracy of ALN metastasis was 83% with 58% in sensitivity and 95% in specificity, and when cut-off point of SUV was set at 1.8, sensitivity, specificity, and accuracy were 36, 100, and 79%, respectively. On the other hand, the diagnostic accuracy of AUS was 85% with 54% in sensitivity and 99% in specificity. By the combination of 18F-FDG PET/CT and AUS to the axilla, the sensitivity, specificity, and accuracy were 64, 94, and 85%, respectively. If either 18F-FDG PET uptake or AUS was positive in allixa, the probability of axillary metastasis was high; 50% (6 of 12) in 18F-FDG PET uptake only, 80% (4 of 5) in AUS positive only, and 100% (28 of 28) in dual positive. By the combination of AUS and 18F-FDG PET/CT, candidates of SNB were more appropriately selected. The axillary 18F-FDG uptake was correlated with the maximum size and nuclear grade of metastatic foci (p = 0.006 and p = 0.03).

Conclusion

The diagnostic accuracy of 18F-FDG PET/CT was shown to be nearly equal to ultrasound, and considering their limited sensitivities, the high radiation exposure by 18F-FDG PET/CT and also costs of the examination, it is likely that AUS will be more cost-effective in detecting massive axillary tumor burden. However, when we cannot judge the axillary staging using AUS alone, metabolic approach of 18F-FDG PET/CT for axillary staging would enable us a much more confident diagnosis.

Background

Staging of non‐small cell lung cancer (NSCLC) is important for determining choice of treatment and prognosis. The accuracy of FDG‐PET scans for staging of lymph nodes is too low to replace invasive nodal staging. It is unknown whether the accuracy of integrated FDG‐PET/CT scanning makes invasive staging redundant.

Methods

In a prospective study, the mediastinal and/or hilar lymph nodes in patients with proven NSCLC were investigated with integrated FDG‐PET/CT scanning. Pathological confirmation of all suspect lymph nodes was obtained to calculate the accuracy of the fusion images. In addition, the use of the standardised uptake value (SUV) in the staging of intrathoracic lymph nodes was analysed.

Results

105 intrathoracic lymph node stations from 52 patients with NSCLC were characterised. The prevalence of malignancy in the lymph nodes was 36%. The sensitivity of the integrated FDG‐PET/CT scan to detect malignant lymph nodes was 84% and its specificity was 85% (positive likelihood ratio 5.64, negative likelihood ratio 0.19). SUVmax, SUVmean and the SUVmax/SUVliver ratio were all significantly higher in malignant than in benign lymph nodes. The area under the receiver operating curve did not differ between these three quantitative variables, but the highest accuracy was found with the SUVmax/SUVliver ratio. At a cut‐off value of 1.5 for the SUVmax/SUVliver ratio, the sensitivity and specificity to detect malignant lymph node invasion were 82% and 93%, respectively.

Conclusion

The accuracy of integrated FDG‐PET/CT scanning is too low to replace invasive intrathoracic lymph node staging in patients with NSCLC. The visual interpretation of the fusion images of the integrated FDG‐PET/CT scan can be replaced by the quantitative variable SUVmax/SUVliver without loss of accuracy for intrathoracic lymph node staging.

Introduction. To determine the value of a FDG-PET-CT scan in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) prior to chemoradiotherapy. Materials and Methods. Consecutive patients with stage III or IV HNSCC who had undergone a staging FDG-PET-CT scan prior to chemoradiotherapy between August 2008 and April 2011 were included. Clinical details and conventional imaging (CT and/or MRI) were, retrospectively, reviewed, a TNM stage was assigned, and levels of cervical lymph node involvement were documented. This process was repeated with the addition of FDG-PET-CT. Radiotherapy plans were reviewed for patients with an alteration identified on TNM staging and/or nodal level identification with FDG-PET-CT and potential alterations in radiotherapy planning were documented. Results. 55 patients were included in the analysis. FDG-PET-CT altered the TNM stage in 17/55 (31%) of patients, upstaging disease in 11 (20%) and downstaging in 6 (11%); distant metastases were identified by FDG-PET-CT in 1 (2%) patient. FDG-PET-CT altered the lymph node levels identified in 22 patients (40%), upclassifying disease in 16 (29%) and downclassifying in 6 (11%). Radiotherapy plans were judged retrospectively to have been altered by FDG-PET-CT in 10 patients (18%). Conclusions. The use of FDG-PET-CT potentially impacts upon both treatment decisions and radiotherapy planning.

Background

Positron emission tomography with 2-deoxy-2-[18F]fluoro-d-glucose (FDG-PET) is available for evaluation of patients with melanoma. This study evaluates the potential of FDG-PET to improve on conventional imaging (CI) in patients with stage IV melanoma undergoing metastasectomy.

Methods

This was a prospective study comparing radiological evaluation of patients who underwent metastasectomy for palliation or cure. Patients underwent preoperative evaluation by physical examination, CI by computed tomography and/or magnetic resonance imaging, and FDG-PET. Independent observers performed three separate analyses of CI alone, FDG-PET alone, or FDG-PET read with knowledge of CI (FDG-PET + CI). Abnormalities were reported as benign or malignant and assessed by pathologic analysis or by clinical outcome determined by disease progression detected on serial evaluations.

Results

Ninety-four lesions were noted in 18 patients who underwent preoperative assessment, metastasectomy, and long-term follow up (median, 24 months). Lesion-by-lesion analysis for CI demonstrated a sensitivity of 76%, a specificity of 87%, a positive predictive value (PPV) of 86%, and a negative predictive value (NPV) of 76%. FDG-PET demonstrated a sensitivity of 79%, a specificity of 87%, a PPV of 86%, and an NPV of 80%. For FDG-PET + CI, the sensitivity was 88%, specificity was 91%, and PPV and NPV were 91% and 88%, respectively.

Conclusions

Combined use of FDG-PET and CI may be an accurate strategy to identify sites of disease in patients with stage IV melanoma being considered for metastasectomy. Interpreted independently, FDG-PET and CI seemed to be equivalent modalities. FDG-PET + CI had both the highest sensitivity on lesion-by-lesion analysis and the best accuracy on patient-by-patient analysis.

Objective: Because the detection of the primary tumour is of importance to optimize the patient’s management and allows a targeted therapy, the performance of hybrid positron emission tomography–computed tomography (PET/CT) using fluorodeoxyglucose (FDG) in the detection of primary tumors and unrecognized metastases with cervical lymph node metastases were evaluated in a retrospective study.

Material and Methods: Twenty patients with cervical lymph node metastases of unknown primary tumors underwent staging with FDG-PET/CT. All underwent head and neck examinations, computed tomography (CT), and/or magnetic resonance imaging (MRI), panendoscopies, and biopsies of head and neck mucosal sites. The diagnostic accuracy of FDG-PET/CT in detecting primary tumors was compared with that of histopathology and clinical follow-up. The ability of FDG-PET/CT to detect distant metastases was also tested.

Results: PET/CT was positive with an increased FDG uptake suggesting the potential primary site in 45% of patients (9/20). PET/CT findings were true positive in 7, true negative in 10, false positive in 2, and false negative in 1 patients, resulting in a sensitivity of 87%, a specificity of 83%, an accuracy of 85%, a positive predictive value of 77% and a negative predictive value of 90%. Also, PET/CT showed distant metastases in seven patients.

Conclusion: FDG-PET/CT can be successfully used for the identification of the primary site and distant metastases in patients with cervical lymph node metastases from an unknown primary cancer.

Conflict of interest:None declared.

Purpose

To investigate the clinical benefits of F18-fluorodeoxyglucose-positron emission tomography and computed tomography (18F-FDG-PET/CT) over multi-detector row CT (MDCT) in preoperative staging of gastric cancer.

Methods

FDG-PET/CT and MDCT were performed on 78 patients with gastric cancer pathologically diagnosed by endoscopy. The accuracy of radiologic staging retrospectively was compared to pathologic result after curative resection.

Results

Primary tumors were detected in 51 (65.4%) patients with 18F-FDG-PET/CT, and 47 (60.3%) patients with MDCT. Regarding detection of lymph node metastasis, the sensitivity of FDG-PET/CT was 51.5% with an accuracy of 71.8%, whereas those of MDCT were 69.7% and 69.2%, respectively. The sensitivity of 18F-FDG-PET/CT for a primary tumor with signet ring cell carcinoma was lower than that of 18F-FDG-PET/CT for a primary tumor with non-signet ring cell carcinoma (35.3% vs. 73.8%, P < 0.01).

Conclusion

Due to its low sensitivity, 18F-FDG-PET/CT alone shows no definite clinical benefit for prediction of lymph node metastasis in preoperative staging of gastric cancer.

Purpose of the study

Fever of unknown origin (FUO) is a challenging clinical entity in HIV patients. FDG-PET/CT is well validated in the work-up of FUO in HIV-negative patients but in HIV viremic patients, metabolism of HIV reactive lymph nodes could decrease its specificity. We prospectively evaluated the usefulness of FDG-PET/CT in FUO in HIV-positive patients and in particular whether HIV viremia impacts on FDG-PET/CT performance.

Methods

FDG-PET/CT was performed in 20 HIV patients with FUO and compared with FDG-PET/CT in 10 HIV viremic patients without FUO. Final diagnosis for FUO was based on histopathology, microbiology, or clinical and imaging follow-up. Mode of diagnosis, accordance of FDG-PET/CT with final diagnosis, localization of invasive diagnosis procedures was recorded in order to assess usefulness of FDG-PET/CT.

Results

FDG-PET/CT showed a different pattern in FUO and asymptomatic viremic patients. Reactive HIV lymph nodes in asymptomatic viremic patients were mostly peripheral with mean SUVmax of 6.5. In patients with FUO and underlying focal pathologies, hypermetabolic lymph nodes were central with mean SUVmax of 11.6. Presence of central lymph nodes with high FDG uptake in had a 100% specificity for focal pathology, even in viremic patients and absence of these had 100% negative predictive value. Lymph node biopsy in central hypermetabolic areas allowed identifying underlying disease in all FUO patients. For peripheral lymph nodes, a ROC curve was built in order to define the best cut-off of SUVmax for biopsy: SUVmax of 6–8 showed a sensitivity of 62.5% and specificity of 75%. Lymph nodes with SUVmax<4 had sensitivity of 0%.

Conclusions

FDG-PET/CT contributed to the diagnosis or exclusion of a focal etiology of the febrile state in 80% of HIV patients with FUO. Although number of patients was small, we could highlight several clear-cut features to help interpreting FDG-PET/CT in HIV patients with FUO. As in HIV-negative patients, we showed the usefulness of FDG-PET/CT in FUO in HIV patients even if they are viremic.

Purpose

The aim of this study was to assess the accuracy of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT to visualize lymph node metastases before the start of neoadjuvant chemotherapy and to determine how often the visualization is sufficiently prominent to allow monitoring of the axillary response.

Methods

Thirty-eight patients with invasive breast cancer of >3 cm and/or lymph node metastasis underwent FDG PET/CT before neoadjuvant chemotherapy. The results of the FDG PET/CT were compared with those from ultrasonography with fine-needle aspiration (FNA) cytology or sentinel node biopsy. Patients suitable for response monitoring of the axilla were defined as having either a maximum standardized uptake value (SUVmax) ≥ 2.5 or a tumour to background ratio ≥5 in the most intense lymph node.

Results

The sensitivity and specificity of FDG PET/CT in detecting axillary involvement were 97 and 100%, respectively. No difference existed between the SUVmax of the primary tumour and that from the related most intense lymph node metastasis. Moreover, the mean tumour to background ratio was 90% higher in the lymph nodes compared to the primary tumour (p = 0.006). Ninety-three per cent of the patients had sufficient uptake in the lymph nodes to qualify for subsequent response monitoring of the axilla. A considerable distinction in metabolic activity was observed between the different subtypes of breast cancer. The mean SUVmax in lymph node metastases of oestrogen receptor (ER)-positive, triple-negative and human epidermal growth factor receptor 2 (HER2)-positive tumours was 6.6, 11.6 and 6.6, respectively.

Conclusion

The high accuracy in visualizing lymph node metastases and the sufficiently high SUVmax and tumour to background ratio at baseline suggest that it is feasible to monitor the axillary response with FDG PET/CT, especially in triple-negative tumours.

Purpose

To determine the anatomic distribution of gross supraclavicular nodes within the supraclavicular fossa using 2-deoxy-2-[F-18] fluoro-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) scans, and to evaluate likely coverage of specific regions of the supraclavicular fossa using standard radiation fields.

Methods and Materials

We identified 33 patients with advanced or metastatic breast cancer who had a PET/CT scan demonstrating hypermetabolic supraclavicular lymph nodes in 2005. The locations of the involved lymph nodes were mapped onto a single CT set of images of the supraclavicular fossa. These lymph nodes were also mapped onto the treatment-planning CT dataset of 4 patients treated in our institution (2 patients with biopsy-proven supraclavicular nodes and 2 patients with clinically negative supraclavicular nodes).

Results

We were able to determine the distribution of 52 supraclavicular lymph nodes in 32 patients. Of 32 patients, 28 (87%) had a history of metastatic disease, and 2 patients had isolated nodal recurrences. Five patients had supraclavicular nodes posterior to the vertebral body transverse process, and several lymph nodes were in close proximity to the medial field border, raising the possibility of geographic miss in these areas.

Conclusions

In patients with locally advanced disease, increased coverage of the supraclavicular fossa medially and posteriorly may be warranted.

In locally advanced cervical cancer, 18F-fluorodeoxyglucose (FDG) positron emission tomography – computed tomography (PET/CT) has become important in the initial evaluation of disease extent. It is superior to other imaging modalities for lymph node status and distant metastasis. PET-defined cervical tumor volume predicts progression-free and overall survival. Higher FDG uptake in both primary and regional lymph nodes is strongly predictive of worse outcome. FDG-PET is useful for assessing treatment response 3 months after completing concurrent chemo-radiotherapy (CRT) and predicting long-term survival, and in suspected disease recurrence. In the era of image-guided adaptive radiotherapy, accurately defining disease areas is critical to avoid irradiating normal tissue. Based on additional information provided by FDG-PET, radiation treatment volumes can be modified and higher doses to FDG-positive lymph nodes safely delivered. FDG-PET/CT has been used for image-guided brachytherapy of FDG-avid tumor volume, while respecting low doses to bladder and rectum. Despite survival improvements due to CRT in cervical cancer, disease recurrences continue to be a major problem. Biological rationale exists for combining novel non-cytotoxic agents with CRT, and drugs targeting specific molecular pathways are under clinical development. The integration of these targeted therapies in clinical trials, and the need for accurate predictors of radio-curability is essential. New molecular imaging tracers may help identifying more aggressive tumors. 64Cu-labeled diacetyl-di(N(4)-methylthiosemicarbazone) is taken up by hypoxic tissues, which may be valuable for prognostication and radiation treatment planning. PET/CT imaging with novel radiopharmaceuticals could further impact cervical cancer treatment as surrogate markers of drug activity at the tumor microenvironment level. The present article reviews the current and emerging role of PET/CT in the management of cervical cancer.

Background

The role of positron emission tomography with the glucose analogue [18F] fluoro‐2‐deoxy‐D‐glucose (FDG‐PET) in the initial staging of disease in patients with primary colorectal cancer (CRC) has not been adequately assessed.

Aims

To evaluate the additional value of FDG‐PET as a staging modality, complementary to routine multidetector row computed tomography (MDCT) in patients with CRC.

Methods

Forty four patients with CRC underwent preoperative MDCT and FDG‐PET. The accuracy of intraoperative macroscopic staging was also investigated compared with histopathological diagnosis. All FDG‐PET images were evaluated with respect to detectability of the primary tumour, lymph node involvement, and distant metastases. Both MDCT and FDG‐PET diagnoses and treatment plan were compared with surgical and histopathological results.

Results

Thirty seven patients underwent surgery. Tumour detection rate was 95% (42/44) for MDCT, 100% (44/44) for FDG‐PET, and 100% (37/37) for intraoperative macroscopic diagnosis. Pathological diagnosis of T factor was T1 in five, T2 in four, T3 in 24, and T4 in four cases. Concordance rate with pathological findings of T factor was 57% (21/37) for MDCT and 62% (23/37) for macroscopic diagnosis. Lymph node involvement was pathologically positive in 19 cases. Regarding N factor, overall accuracy was 62% (23/37) for MDCT, 59% (22/37) for FDG‐PET, and 70% (26/37) for macroscopic diagnosis. For all 44 patients, FDG‐PET findings resulted in treatment changes in only one (2%) patient.

Conclusion

FDG‐PET is not superior to routine MDCT in the initial staging of primary CRC.

Purpose

To evaluate the feasibility of PET/MRI (positron emission tomography/magnetic resonance imaging) with FDG (18F-fluorodeoxyglucose) for initial staging of head and neck cancer.

Methods

The study group comprised 20 patients (16 men, 4 women) aged between 52 and 81 years (median 64 years) with histologically proven squamous cell carcinoma of the head and neck region. The patients underwent a PET scan on a conventional scanner and a subsequent PET/MRI examination on a whole-body hybrid system. FDG was administered intravenously prior to the conventional PET scan (267–395 MBq FDG, 348 MBq on average). The maximum standardized uptake values (SUVmax) of the tumour and of both cerebellar hemispheres were determined for both PET datasets. The numbers of lymph nodes with increased FDG uptake were compared between the two PET datasets.

Results

No MRI-induced artefacts where observed in the PET images. The tumour was detected by PET/MRI in 17 of the 20 patients, by PET in 16 and by MRI in 14. The PET/MRI examination yielded significantly higher SUVmax than the conventional PET scanner for both the tumour (p < 0.0001) and the cerebellum (p = 0.0009). The number of lymph nodes with increased FDG uptake detected using the PET dataset from the PET/MRI system was significantly higher the number detected by the stand-alone PET system (64 vs. 39, p = 0.001).

Conclusion

The current study demonstrated that PET/MRI of the whole head and neck region is feasible with a whole-body PET/MRI system without impairment of PET or MR image quality.

Purpose

To evaluate the prognostic value of preoperative neck lymph node (LN) assessment with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), computed tomography (CT), and magnetic resonance imaging (MRI) in oral cavity squamous cell carcinoma (OSCC) patients with pathologically positive LN.

Materials and Methods

In total, 47 OSCC patients with pathologically positive LN were retrospectively reviewed with preoperative 18F-FDG PET and CT/MRI. All patients underwent surgical resection, neck dissection and postoperative adjuvant radiotherapy and/or chemotherapy between March 2002 and October 2010. Histologic correlation was performed for findings of 18F-FDG PET and CT/MRI.

Results

Thirty-six (76.6%) of 47 cases were correctly diagnosed with neck LN metastasis by 18F-FDG PET and 32 (68.1%) of 47 cases were correctly diagnosed by CT/MRI. Follow-up ranged from 20 to 114 months (median, 56 months). Clinically negative nodal status evaluated by 18F-FDG PET or CT/MRI revealed a trend toward better clinical outcomes in terms of overall survival, disease-free survival, local recurrence-free survival, regional nodal recurrence-free survival, and distant metastasis-free survival rates even though the trends were not statistically significant. However, there was no impact of neck node standardized uptake value (SUVmax) on clinical outcomes. Notably, SUVmax showed significant correlation with tumor size in LN (p < 0.01, R2 = 0.62). PET and CT/MRI status of LN also had significant correlation with the size of intranodal tumor deposit (p < 0.05, R2 = 0.37 and p < 0.01, R2 = 0.48, respectively).

Conclusion

18F-FDG PET and CT/MRI at the neck LNs might improve risk stratification in OSCC patients with pathologically positive neck LN in this study, even without significant prognostic value of SUVmax.

Aim. to compare 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) to sentinel lymph node biopsy (SLNB) for regional lymph nodal staging in patients with melanoma. Methods. We performed a literature review discussing original articles which compared FDG-PET to SLNB for regional lymph nodal staging in patients with melanoma. Results and Conclusions. There is consensus in the literature that FDG-PET cannot replace SLNB for regional lymph nodal staging in patients with melanoma.

Background

18Fluoro-2-Deoxy Glucose (18 FDG) positron emission tomography (PET) impacts upon the management of recurrent colorectal cancer (CRC) but is limited by anatomical localisation. The development of integrated positron emission and computerised tomography (PET/CT) yields high anatomical resolution combined with the PET data. We evaluate the added value of PET/CT over PET alone.

Method

Thirty-one consecutive patients had PET/CT for suspected recurrent CRC. Two blinded observers (A and B) reported images from PET alone and from integrated PET/CT. Lesion detection, lesion localisation, diagnostic certainty and impact on surgical management was assessed for each data set and then compared. The minimum clinical follow up was for 8 months (median 9.6 months) and 7 patients had histological confirmation of diagnosis.

Results

Compared to PET alone, PET/CT the percentage of lesions accurately localised increased from 96% to 99% for observer A and 86% to 99% for Observer B. PET/CT increased the number of lesions reported as definitely abnormal or normal from 78% to 95% for Observer A and from 72% to 94% for Observer B. Surgical management was changed in 6 patients (19%). Inter-observer variability was reduced with PET/CT.

Conclusion

PET/CT improves the accuracy of reporting in recurrent colorectal cancer and influences surgical management in a significant proportion of patients when compared to PET only imaging.

BACKGROUND: A study was undertaken to investigate the accuracy of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D- glucose (FDG) in the thoracic lymph node staging of non-small cell lung cancer (NSCLC). METHODS: Forty six patients with focal pulmonary tumours who underwent preoperative computed tomographic (CT) and FDG- PET scanning were evaluated retrospectively. Thirty two patients had NSCLC and 14 patients had a benign process. The final diagnosis was established by means of histopathological examination at thoracotomy, and the nodal classification in patients with lung cancer was performed by thorough dissection of the mediastinal nodes at surgery. RESULTS: FDG-PET was 80% sensitive, 100% specific, and 87.5% accurate in staging thoracic lymph nodes in patients with NSCLC, whereas CT scanning was 50% sensitive, 75% specific, and 59.4% accurate. The absence of lymph node tumour involvement was identified by FDG-PET in all 12 patients with NO disease compared with nine by CT scanning. Lymph node metastases were correctly detected by FDG-PET in three of five patients with N1 disease compared with two by CT scanning, in nine of 11 with N2 disease compared with six by CT scanning, an in all four with N3 nodes compared with two by CT scanning. CONCLUSIONS: FDG-PET provides a new and effective method for staging thoracic lymph nodes in patients with lung cancer and is superior to CT scanning in the assessment of hilar and mediastinal nodal metastases. With regard to resectability, FDG-PET could differentiate reliably between patients with N1/N2 disease and those with unresectable N3 disease. 




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.

CONCLUSION

In 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.

Background

The prognostic significance of primary tumor location, especially the poor prognosis for melanomas in the scalp and neck region, is well established. However, the prognosis for different sites of nodal macrometastasis has never been studied. This study investigated the prognostic value of the location of macrometastasis in terms of recurrence and survival rates after therapeutic lymph node dissection (TLND).

Methods

All consecutive FDG-PET-staged melanoma patients with palpable and cytologically proven lymph node metastases operated at our clinic between 2003 and 2011 were included. Disease-free survival and disease-specific survival (DSS) were compared for nodal metastases in the groin, axilla, and neck regions by multivariable analysis.

Results

A total of 149 patients underwent TLND; there were 70 groin (47 %), 57 axillary (38 %), and 22 neck (15 %) dissections. During a median follow-up of 18 (range 1–98) months, 102 patients (68 %) developed recurrent disease. Distant recurrence was the first sign of progressive disease in 78, 76, and 55 % of the groin, axilla, and neck groups, respectively (p = 0.26). Low involved/total lymph nodes (L/N) ratio (p < 0.001) and absence of extranodal growth pattern (p = 0.05) were independent predictors of a longer disease-free survival. For DSS, neck site of nodal metastasis (p = 0.02) and low L/N ratio (p < 0.001) were independent predictors of long survival. The estimated 5-year DSS for the groin, axilla, and neck sites was 28, 34, and 66 %, respectively.

Conclusions

There seems significantly longer DSS after TLND for nodal macrometastases in the neck compared to axillary and groin sites, although larger series should confirm this finding.

We report the hybrid FDG PET/CT appearance of a biopsy-proven pancreatic metastasis from prostate cancer in a man with castrate-resistant metastatic disease. The common sites of metastases from prostate cancer are bone and locoregional lymph nodes. Pancreas is an atypical location of metastasis from prostate cancer. PET/CT in this case helped with the targeted pathologic confirmation to differentiate primary pancreatic tumor from an unusual metastasis from prostate cancer which in turn impacted the clinical management.

Objective

The aim of this study was to assess the diagnostic efficacy of integrated PET/CT using fluorodeoxyglucose (FDG) for the differentiation of benign and metastatic adrenal gland lesions in patients with lung cancer and to compare the diagnostic efficacy with the use of PET alone.

Materials and Methods

Sixty-one adrenal lesions (size range, 5-104 mm; mean size, 16 mm) were evaluated retrospectively in 42 lung cancer patients. Both PET images alone and integrated PET/CT images were assessed, respectively, at two-month intervals. PET findings were interpreted as positive if the FDG uptake of adrenal lesions was greater than or equal to that of the liver, and the PET/CT findings were interpreted as positive if an adrenal lesion show attenuation > 10 HU and showed increased FDG uptake. Final diagnoses of adrenal gland lesions were made at clinical follow-up (n = 52) or by a biopsy (n = 9) when available. The diagnostic accuracies of PET and PET/CT for the characterization of adrenal lesions were compared using the McNemar test.

Results

Thirty-five (57%) of the 61 adrenal lesions were metastatic and the remaining 26 lesions were benign. For the depiction of adrenal gland metastasis, the sensitivity, specificity, and accuracy of PET were 74%, 73%, and 74%, respectively, whereas those of integrated PET/CT were 80%, 89%, and 84%, respectively (p values; 0.5, 0.125, and 0.031, respectively).

Conclusion

The use of integrated PET/CT is more accurate than the use of PET alone for differentiating benign and metastatic adrenal gland lesions in lung cancer patients.

AIM: To compare the diagnostic accuracy of computed tomography (CT) and positron emission tomography (PET) for the preoperative detection of paraaortic lymph node (PAN) metastasis in patients with intra-abdominal malignancies.

METHODS: Sixty-six patients with intra-abdominal malignancies who underwent both CT and PET before lymphadenectomy were included in this study. Histopathologically, 13 patients had metastatic PAN, while 53 had non-metastatic PAN. The CT criteria for metastasis were: short diameter of > 8 mm, lobular or irregular shape, and/or combined ancillary findings, including necrosis, conglomeration, vessel encasement, and infiltration. The PET criterion was positive fluorodeoxyglucose (FDG) uptake. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of both modalities were compared with the pathologic findings, and the false positive and false negative cases with both CT and PET were analyzed.

RESULTS: The sensitivity, specificity, PPV, NPV, and accuracy of CT were 61.5%, 84.9%, 50%, 90% and 80.3%, respectively. For PET, the percentages were 46.2%, 100%, 100%, 88.3%, and 89.4%. Additionally, there were 8 false positive CT cases (8/53, 15.1%) and zero false positive PET cases. Of the 13 metastatic PANs, there were 5 false negative CT scans (38.5%) and 7 (53.9%) false negative PET scans.

CONCLUSION: For detecting PAN metastasis, CT is more sensitive than PET, while PET is more specific.

Positron emission tomography combined with computed tomography (PET/CT) has been receiving increasing attention during the recent years for making the diagnosis, for determining the staging and for the follow-up of various malignancies. The PET/CT findings of 58 breast cancer patients (age range: 34-79 years old, mean age: 50 years) were retrospectively compared with the PET or CT scans alone. PET/CT was found to be better than PET or CT alone for detecting small tumors or multiple metastases, for accurately localizing lymph node metastasis and for monitoring the response to chemotherapy in breast cancer patients.

There are several artifacts unique to PET/CT imaging, with CT-based attenuation correction (AC) artifacts being among the most commonly reported. AC artifacts from calcified lymph nodes represent clinically significant and easily misinterpreted PET/CT artifacts that have received little attention in the literature. In this case series, we report three cases of calcified lymph nodes causing an AC artifact and one case of a highly calcified lymph node without an AC artifact. All three cases of calcified lymph nodes causing an AC artifact would have resulted in a change in patient staging, and likely management, if the nodes had been misinterpreted as malignant nodes. In PET/CT imaging, this artifact needs to be considered as a potential cause of apparent FDG activity when calcified lymph nodes are present on the CT portion of a PET/CT study in order to avoid misinterpretation and potential patient mismanagement.

The case reported here was that of an old woman characterized by pancytopenia, chromosome clonal abnormality, fluctuation of the percent of blast cells at 20%, and negative evidence of malignancy in whole-body 2-[F18] fluoro-2-deoxy-d-glucose positron emission tomography (F18-FDG PET). After about 10 months, the blast cells accounted for about 25%, the morphology of which was similar to that of previous ones, and F18-FDG PET demonstrated diffusing increased uptake in the right upper leg and lymph nodes and patchy high uptake of bone marrow. 2-[F18]-fluoro-2-deoxyglucose can reflect extramedullary infiltration and bone marrow cellularity of the whole body, compared with invasive, regional biopsies and aspirations. The value of 2-[F18]-fluoro-2-deoxyglucose or 3’-deoxy-3’-[F18]-fluorothymidine positron emission tomography as an indicator in predicting the transformation of myelodysplastic syndrome to acute myeloid leukemia needs to be explored in the future.

Background

Positron-emission tomography (PET) imaging using [18F]fluorodeoxyglucose (FDG) is useful for detection, staging, and monitoring a variety of malignancies, including lymphoma, in adults, but its utility in sarcomas, especially soft tissue sarcomas (STS), in children and young adults is not clear.

Procedure

To evaluate the potential utility of FDG PET in the care of STS in children and young adults, we analyzed 46 PET scans in 25 patients acquired over 12 years. Scans were interpreted by two imaging physicians blinded to findings from other imaging studies and clinical information. Results were compared with computed tomography and magnetic resonance imaging, biopsy results, where available, and clinical follow-up of at least 12 months.

Results

For a total of 46 scans in 25 patients, there were 25 true positive scans, 3 false positive scans, 12 true negative scans, and 6 false negative scans. The sensitivity of the PET scan was 86%, specificity was 80%, positive predictive value was 89%, and negative predictive value was 67%.

Conclusion

FDG PET may be a useful imaging modality in the management of children and young adults with STS, although prospective studies are needed to establish its true utility.