Prognostic Significance of Metabolic Tumor Volume Measured by 18F-FDG PET/CT in Operable Primary Breast Cancer

Purpose

We investigated whether PET indices measured by ¹⁸ F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can predict prognosis in patients with operable primary breast cancer.

Methods

We reviewed 53 patients with operable primary breast cancer who underwent pretreatment FDG PET/CT. PET indices, maximum standardized uptake value (SUV) and metabolic tumor volume (MTV), were measured in the primary breast tumor (P), metastatic lymph nodes (N) and total tumor (T). The Cox proportional hazards model was used with age, tumor size, clinical lymph node status, method of surgery, presence or absence of neoadjuvant chemotherapy, histological type, histological grade, hormone receptors and HER2 status to predict disease-free survival (DFS) and overall survival (OS).

Results

Median follow-up period was 50 months (range, 17–73 months), during which 17 patients had recurrent disease and nine of whom died. The univariate analysis showed that high SUV of N (N_SUV, P = 0.011), MTV of N (N_MTV, P = 0.011) and MTV of T (T_MTV, P = 0.045) as well as high histological grade (P = 0.008), negative estrogen (P = 0.045) and negative progesterone (P = 0.029) receptor status were associated with shorter DFS. High N_SUV (P = 0.035), N_MTV (P = 0.035) and T_MTV (P = 0.035) as well as high histological grade (P = 0.012) and negative estrogen receptor status (P = 0.009) were associated with shorter OS. N_SUV, N_MTV and T_MTV were found to be significantly associated with high histological grade (P = 0.005). However, those failed to be statistically significant prognostic factors on multivariate analysis.

Conclusions

PET indices seem to be useful in the preoperative evaluation of prognosis in patients with operable primary breast cancer. N_SUV, N_MTV and T_MTV might be considerable factors associated with patient outcome in operable breast cancer.     

Metabolic Tumor Volume Measured by F-18 FDG PET/CT can Further Stratify the Prognosis of Patients with Stage IV Non-Small Cell Lung Cancer

Purpose

This study aimed to further stratify prognostic factors in patients with stage IV non-small cell lung cancer (NSCLC) by measuring their metabolic tumor volume (MTV) using F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT).

Materials and Methods

The subjects of this retrospective study were 57 patients with stage IV NSCLC. MTV, total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were measured on F-18 FDG PET/CT in both the primary lung lesion as well as metastatic lesions in torso. Optimal cutoff values of PET parameters were measured by receiver operating characteristic (ROC) curve analysis. Kaplan-Meier survival curves were used for evaluation of progression-free survival (PFS). The univariate and multivariate Cox proportional hazards models were used to select the significant prognostic factors.

Results

Univariate analysis showed that both MTV and TLG of primary lung lesion (MTV-lung and TLG-lung) were significant factors for prediction of PFS (P < 0.001, P = 0.038, respectively). Patients showing lower values of MTV-lung and TLG-lung than the cutoff values had significantly longer mean PFS than those with higher values. Hazard ratios (95 % confidence interval) of MTV-lung and TLG-lung measured by univariate analysis were 6.4 (2.5–16.3) and 2.4 (1.0–5.5), respectively. Multivariate analysis revealed that MTV-lung was the only significant factor for prediction of prognosis. Hazard ratio was 13.5 (1.6–111.1, P = 0.016).

Conclusion

Patients with stage IV NSCLC could be further stratified into subgroups of significantly better and worse prognosis by MTV of primary lung lesion.     

Prognostic Value of Volume-Based Metabolic Parameters Measured by 18F-FDG PET/CT of Pancreatic Neuroendocrine Tumors

Purpose

To date, the prognostic value of ¹⁸F-FDG PET/CT for patients with pancreatic neuroendocrine tumors (PNETs) has not been well characterized. We investigated the prognostic value of volumetric parameters using ¹⁸F-FDG PET/CT in this patient population.

Methods

We retrospectively reviewed 20 cases of pathologically proven PNET in patients who had undergone pre-therapeutic ¹⁸F-FDG PET/CT. PET parameters including maximum and average standardized uptake values (SUV_max, SUV_ave), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor were measured using a threshold SUV to determine the boundaries of the tumors. Univariate and multivariate survival analyses were performed with adjustments for PET parameters and other clinical values.

Results

The median clinical follow-up was 22.3 (range, 1.2–95.4) months. Cancer-related death occurred in 5 of 20 patients (25 %). Patients had clinical or pathological stages of I in seven patients, II in six patients, III in three patient, and IV in four patients. According to the WHO histological classification of subtypes, 3 patients exhibited well-differentiated PNETs, 13 patients had well-differentiated endocrine carcinomas, and 4 had poorly differentiatedendocrine carcinomas. Univariate analysis showed that tumor size (p = 0.028), AJCC stage (p = 0.009), T stage (p = 0.028), M stage (p = 0.029), treatment modality (p = 0.045), MTV (p = 0.003) and TLG (p = 0.027) were significant predictors of overall survival. On multivariate analysis, MTV (HR = 10.859, p = 0.031) was a significant independent predictor of overall survival along with the AJCC stage (HR = 11.556, p = 0.027).

Conclusion

In patients with PNETs, the MTV of the primary tumor as measured by ¹⁸F-FDG PET/CT along with the AJCC stage may be a significant independent prognostic factor for overall survival.     

Prognostic Significance of Volume-based Metabolic Parameters by 18F-FDG PET/CT in Gallbladder Carcinoma

Purpose

We investigated the prognostic values of volume-based metabolic parameters by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) in gallbladder carcinoma patients and compared them with other prognostic parameters.

Materials and Methods

We enrolled 44 patients, who were initially diagnosed with gallbladder carcinoma and undergoing ¹⁸F-FDG PET/CT. Various metabolic volume-based PET parameters of primary tumors, including maximum and average standardized uptake values (SUV_max, SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), were measured in gallbladder carcinoma patients using mediastinal blood pool activity as a threshold SUV for determining the tumor boundaries. Overall survival analysis was performed using the Kaplan-Meier method with PET parameters and other clinical variables. For determining independent prognostic factors, Cox proportional hazards regression analysis was performed.

Results

Of the 44 enrolled patients, cancer- or treatment-related death occurred in 30 (68.2 %). The mean clinical follow-up period was 22.2 ± 10.4 m (range, 0.6-35.9 m). Univariate analysis demonstrated that clinical or pathologic TNM stage (P < 0.001), treatment modality (P < 0.001), MTV (cutoff = 135 cm³, P = 0.001), and TLG (cutoff = 7,090, P < 0.05) were significant prognostic factors. In multivariate analysis, both clinical or pathologic TNM stage [hazard ratio (HR) = 2.019 (I vs II), 21.287 (I vs III), and 24.354 (I vs IV); P = 0.001) and TLG (HR = 2.930; P < 0.05) were independent prognostic factors for predicting overall survival.

Conclusions

In gallbladder cancer, TLG of the primary tumor, a volume-based metabolic parameter, is a significant independent prognostic factor for overall survival in conjunction with the clinical or pathological TNM stage.     

Giant Cell Tumor Pulmonary Metastases Mimic Primary Malignant Pulmonary Nodules on 18F-FDG PET/CT

A 59-year-old man with a 30-year history of multiple recurrences of a giant cell tumor (GCT) of the left knee was referred for an ¹⁸F-FDG PET/CT to evaluate a solitary pulmonary nodule. The nodule was mildly FDG-avid, raising suspicion of malignancy. It was excised and histologically proven to be a GCT pulmonary metastasis. A follow-up PET/CT done 2 years later revealed a new, larger lung mass that was more intensely FDG-avid, but of the same histology. This rare report highlights a pitfall in the evaluation of solitary pulmonary lesions by ¹⁸F-FDG PET/CT in patients with GCT of the bone.     

Prognostic Value of Volume-Based 18F-Fluorodeoxyglucose PET/CT Parameters in Patients with Clinically Node-Negative Oral Tongue Squamous Cell Carcinoma

Objective

To evaluate the prognostic value of volume-based metabolic parameters measured with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) in patients with clinically node-negative (cN0) oral tongue squamous cell carcinoma (OTSCC) as compared with other prognostic factors.

Materials and Methods

In this study, we included a total of 57 patients who had been diagnosed with cN0 tongue cancer by radiologic, ¹⁸F-FDG PET/CT, and physical examinations. The maximum standardized uptake value (SUV_max), average SUV (SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for primary tumors were measured with ¹⁸F-FDG PET. The prognostic significances of these parameters and other clinical variables were assessed by Cox proportional hazards regression analysis.

Results

In the univariate analysis, pathological node (pN) stage, American Joint Committee on Cancer (AJCC) stage, SUV_max, SUV_avg, MTV, and TLG were significant predictors for survival. On a multivariate analysis, pN stage (hazard ratio = 10.555, p = 0.049), AJCC stage (hazard ratio = 13.220, p = 0.045), and MTV (hazard ratio = 2.698, p = 0.033) were significant prognostic factors in cN0 OTSCC patients. The patients with MTV ≥ 7.78 cm³ showed a worse prognosis than those with MTV < 7.78 cm³ (p = 0.037).

Conclusion

The MTV of primary tumor as a volumetric parameter of ¹⁸F-FDG PET, in addition to pN stage and AJCC stage, is an independent prognostic factor for survival in cN0 OTSCC.     

口腔鳞癌的18F-FDG PET/CT的影像学表现以及与CT平扫的比较研究

目的 评价18F-FDG PET-CT检查在口腔鳞癌患者的诊断和淋巴结转移灶发现的价值.方法 回顾性地分析了18例口腔癌(其中包括16例舌癌和2例口底癌患者)的临床和18F-FDG PET-CT影像学表现及CT平扫的影像学资料.结果 (1)原发病灶的发现全部病例中有5例患者是由PET/CT检查首次发现口腔癌的;PET/CT对原发部位肿瘤病变显示的灵敏度100%(15/15),特异性100%(3/3);CT对原发病灶显示的灵敏度为73.3%(11/15),特异性为66.7%(2/3).(2)18例口腔癌患者中PET/CT诊断颈部淋巴结转移灶共26个,大小介于0.8～1.5 cm之间,标准摄取值(SUV)介于2.5～3.2之间;其中仅有5个淋巴结经病理组织活检证实为淋巴结转移灶.(3)通过PET/CT检查新发现全身其他部位的侵犯和远处转移性病灶8个.结论 PET/CT对口腔鳞癌原发灶诊断的灵敏度和特异性均比CT平扫高;全身PET/CT扫描对舌癌和口底癌的临床分期、术后复发的判定更具价值.     

^18FDG—PET在诊断头颈部鳞状细胞癌复发中的价值

目的了解18FDG-PET在诊断头颈部鳞状细胞癌复发中的价值,确定标准吸收值(SUV)来鉴别放疗后的炎症与肿瘤复发.材料和方法头颈部鳞状细胞癌患者43例,在放疗后至少4个月(平均11个月)进行18FDG-PET检查.计算感兴趣区的SUV值.肿瘤复发诊断依赖组织病理学检查或6个月以上的临床随访.结果43例患者中,FDG-PET阳性23例,其中3例为假阳性;20例为阴性,其中假阴性2例.FDG-PET的诊断准确性是88%(38/43),而CT/MRI的诊断准确性则为66%(25/38).肿瘤复发病灶和炎症病灶的SUV有部分重叠,无统计学上差异(p=0.31).结论18FDG-PET检测头颈部鳞状细胞癌复发中肉眼分析更有价值;18FDG-PET较CT/MRI更为准确.     

Prognostic Value of Metabolic Activity Measured by 18F-FDG PET/CT in Patients with Advanced Endometrial Cancer

Purpose

We evaluated the potential prognostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with stage IIIC/IV endometrial cancer.

Methods

Patients with stage IIIC/IV endometrial cancer who had undergone FDG PET/CT workup for staging were enrolled. Maximum standardized uptake values (SUVmax) measured from regions of interest (ROIs) of the primary tumor (SUVt) and lymph nodes (SUVn) were correlated with overall survival (OS). The SUVn was defined as the highest SUVmax of the metastatic lymph nodes. Survival probability was assessed using the Kaplan-Meier method.

Results

A total of 42 patients with a median age of 55.5 years (range 32–76 years) were included. Twenty-nine percent (n = 12) of patients were premenopausal and 71 % (n = 30) were postmenopausal. The average SUVt was 12.9 (range 1.8–36.5), and the average SUVn was 7.3 (range 2.0–22.5). Median follow-up time was 25.9 months (range 1–84 months). Using a SUVt of 9.5 as a cutoff value, two groups with different rates were determined (P = 0.026). In addition, patients with a low SUVn had significantly better OS than those with a high SUVn (P = 0.003). Patients in the International Federation of Obstetrics and Gynecology (FIGO) stage IV group with SUVt ≥ 9.5 or SUVn ≥ 7.3 showed a significantly longer OS than the other groups.

Conclusions

FDG uptake of primary endometrial cancer and lymph nodes might be a prognostic factor in advanced endometrial cancer. More aggressive therapy could be considered in patients with stage IV endometrial cancer and high SUVt and/or high SUVn.     

The Prognostic Value of the Metabolic Tumor Volume in FIGO stage IA to IIB Cervical Cancer for Tumor Recurrence: Measured by F-18 FDG PET/CT

Purpose

The purpose of this study was to evaluate the prognostic value of the metabolic tumor volume (MTV), in FIGO stage IA–IIB cervical cancer patients, measured by F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging.

Methods

Forty-five patients with invasive cervical cancer who underwent FDG-PET imaging were recruited. Metabolically active tumor regions were delineated on the pretreatment FDG-PET scans by encompassing regions equal to or greater than an standardized uptake value (SUV) of 40% of the peak tumor intensity. The relationship of the metabolic tumor volume (MTV) to the disease-free survival was analyzed. The MTV of the cervical cancer was compared with pathological and clinical prognostic factors, including lymph node metastasis, parametrial invasion, the depth of invasion, resection margins, tumor differentiation and FIGO stages.

Results

Cox proportional hazard regression analysis showed that the MTV was a significant independent predictor of recurrence of cervical cancer (p = 0.027). Patients with an MTV of >20 cm³ had a significantly reduced disease-free survival compared with patients with an MTV ≤ 20 cm³ (p = 0.029). The correlation of the MTV with traditional prognostic factors showed significantly higher values in patients that were lymph node (LN) metastasis positive (p = 0.028) and parametrial invasion positive (p = 0.022). The MTV significantly differed among the groups according to tumor differentiation (p = 0.0319) and FIGO stage (p = 0.001).

Conclusion

The MTV measured by FDG-PET was an independent prognostic factor for tumor recurrence in patients with stage IA–IIB cervical cancer. These findings must be confirmed by large population based prospective studies.     

Tenosynovial Giant Cell Tumor of Diffuse Type Mimicking Bony Metastasis Detected on F-18 FDG PET/CT

Tenosynovial giant cell tumor of diffuse type (TGCT-D) is a locally aggressive neoplasm that arises in the tendon sheath, bursa, or synovium. It typically involves the appendicular skeleton and rarely involves the axial skeleton. Because there are no specific findings of TGCT-D based on imaging studies or clinical symptoms, TGCT-D can be confused with other primary or metastatic bone tumors. We report findings of TGCT-D involving the T9 vertebra incidentally detected on F-18 FDG PET/CT in a patient with papillary thyroid cancer.     

Scalene muscle uptake: a potential pitfall in head and neck PET/CT

Purpose To describe increased 2-deoxy-2-[¹⁸F] fluoro-D-glucose (FDG) uptake in the scalene muscles in a large population of patients referred for evaluation with FDG positron emission tomography/computed tomography (PET/CT) imaging. Methods The study met criteria for institutional review board exemption. FDG PET/CT images from 410 patients (179 males; mean age 56.8 years, range 6-88) were retrospectively reviewed for the presence or absence of FDG uptake in the neck that corresponded to the scalene muscles on the concurrent CT scan. Medical records were reviewed and data including age, sex, smoking history, reason for referral, and history of obstructive airways disease, thoracotomy, and thoracic radiation were recorded and evaluated. Results One hundred and forty-seven of the 410 scans (36%) demonstrated increased FDG uptake on PET that corresponded to the scalene muscles on the CT scan. The uptake was most often bilateral, symmetrical, and linear (n = 117). Other patterns of scalene muscle uptake included unilateral and linear uptake (n = 27) and unilateral and focal uptake (n = 3). Scalene muscle uptake was more common in patients referred for evaluation of lung carcinomas compared to other types of tumors (52% vs. 32%, p = 0.05). Conclusion Linear FDG uptake in scalene muscles is a commonly seen pattern on PET/CT. This finding should be recognized as a distinct entity and not misinterpreted on transverse images as metastatic disease.     

Respiratory-gated F-FDG PET/CT for the diagnosis of liver metastasis

Purpose

To ascertain the role of respiratory-gated PET/CT with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) for accurate diagnosis of liver metastasis.

Materials and methods

Forty patients with suspected liver metastasis underwent conventional whole-body PET/CT scan initially, followed by respiratory-gated PET/CT scan covering the liver. Visual detectability (using a 5-point confidence scale), maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of hepatic metastatic lesions were assessed for three data sets including ordinary whole-body (WB) scan, and non-respiratory-gated (nRG) and respiratory-gated (RG) scans. Results of enhanced CT and/or MRI, or clinical and radiological follow-up were used for reference.

Results

Sixteen of the patients were found to have 53 metastatic lesions in the liver. Patient-based accuracy of WB, nRG, and RG was 92.5%, 95.0%, and 97.5%, respectively, with a lesion-based detection rate of 67.9%, 73.6%, and 73.6%, respectively. The average SUVmax of 34 liver metastatic lesions for WB, nRG, and RG was 6.60 ± 2.34, 7.19 ± 2.66, and 8.08 ± 3.24, respectively. SUVmax for RG was significantly higher than that for WB (p = 0.0069). The average MTV of these 40 lesions for the three protocols was 5.32 ± 4.78 cm³, 5.07 ± 4.73 cm³, and 4.73 ± 4.67 cm³, respectively. Among the three protocols, RG showed the best visual and quantitative evaluation for diagnosis of liver metastasis.

Conclusion

Respiratory-gated PET/CT allows more accurate identification of liver metastases than non-respiratory-gated PET/CT.     

Prognostic Value of Primary Tumor Uptake on F-18 FDG PET/CT in Patients with Invasive Ductal Breast Cancer

Purpose

To determine the prognostic implications of pretreatment F-18 FDG PET/CT in patients with invasive ductal breast cancer (IDC), we evaluated the relationship between FDG uptake of the primary tumor and known prognostic parameters of breast cancer. Prognostic significance of tumoral FDG uptake for the prediction of progression-free survival (PFS) was also assessed.

Materials and Methods

Fifty-five female patients with IDC who underwent pretreatment F-18 FDG PET/CT were enrolled. The maximum standardized uptake value of the primary tumor (pSUVmax) was compared with clinicopathological parameters including tumor size, grade, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor2 (HER2), axillary lymph node (LN) metastasis, and stage. The prognostic value of pSUVmax for PFS was assessed using the Kaplan-Meier method.

Results

A high pSUVmax was significantly related to a higher stage of tumor size (P < 0.05), grade (P < 0.001), and stage (P < 0.001). pSUVmax was significantly higher in ER-negative tumors (P < 0.001), PR-negative tumors (P < 0.001), and positive LN metastasis (P < 0.01), but not different according to HER2 status. pSUVmax was significantly higher in patients with progression compared to patients who were disease-free (10.6 ± 5.1 vs. 4.7 ± 3.5, P < 0.001). A receiver-operating characteristic curve demonstrated a pSUVmax of 6.6 to be the optimal cutoff for predicting PFS (sensitivity; 86.7%, specificity; 82.5%). The patients with a high pSUVmax (more than 6.6) had significantly shorter PFS compared to patients with a low pSUVmax (P < 0.0001).

Conclusions

pSUVmax on pretreatment F-18 FDG PET/CT could be used as a good surrogate marker for the prediction of progression in patients with IDC.     

Value of 18F-FDG PET/CT in the Detection of Ovarian Malignancy

Purpose

Ovarian cancer is a leading cause of gynecologic malignancy. As symptoms of ovarian cancer are nonspecific, only 20 % of ovarian cancers are diagnosed while they are still limited to the ovaries. Thus, early and accurate detection of disease is important for an improved prognosis. For the accurate and effective diagnosis of ovarian malignancy on ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT), we analyzed several parameters, including visual assessment.

Method

A total of 51 peritoneal lesions in 19 patients who showed ovarian masses with diffuse peritoneal infiltration were enrolled. Twelve patients were confirmed to have ovarian malignancy and seven patients with benign disease by pathologic examination. All patients were examined by ¹⁸F-FDG PET/CT, and an additional 2-h delayed ¹⁸F-FDG PET/CT was also performed for 15 patients with 42 peritoneal lesions. We measured semiquantitative parameters including maximum and mean standardized uptake values (SUVmax, SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on a 1-h initial ¹⁸F-FDG PET/CT image (Parameter₁) and on a 2-h delayed image (Parameter₂). Additionally, retention indices of each parameter were calculated, and each parameter among the malignant and benign lesions was compared by Mann-Whitney U test. We also assessed the visual characteristics of each peritoneal lesion, including metabolic extent, intensity, shape, heterogeneity, and total visual score. Associations between visual grades and malignancy were analyzed using linear by linear association methods. Moreover, a receiver operating characteristic (ROC) curve was analyzed to compare the effectiveness of significant parameters.

Result

In a comparison between the malignant and benign groups in the analysis of 51 total peritoneal lesions, SUVmax₁, SUVmean₁, and TLG₁ showed significant differences. Also, in the analysis of 42 peritoneal lesions that underwent an additional 2-h ¹⁸F-FDG PET/CT examination, SUVmax_1,2, SUVmean_1,2, TLG₂, and the RI of TLG showed significant differences between the malignant and benign groups. MTV did not show significant differences in either the analysis of 51 peritoneal lesions or of 42 lesions. Regarding visual assessments, metabolic intensity, shape, heterogeneity, and total visual score showed an association with malignancy. In the ROC analysis, the AUC of the visual score was larger than the AUC of other parameters in both the analyses of 51 peritoneal lesions and of 42 lesions.

Conclusion

Although further study with a larger patient population is needed, the visual assessment of ¹⁸F-FDG PET/CT imaging has a primary role in the detection of malignancy in ovarian cancer patients with assistance from other semi-quantitative parameters.     

Brown fat in breast cancer patients: analysis of serial 18F-FDG PET/CT scans

Purpose It has recently been suggested that FDG accumulation in the brown adipose tissue varies as a function of age, sex and outdoor temperature. The aim of this study was to assess changes in FDG uptake in brown fat in patients based on serial PET/CT scans and to compare our results with previous findings. Methods Early response to neoadjuvant chemotherapy in 33 female breast cancer patients was assessed by FDG PET. Five PET/CT scans were performed for each patient. PET/CT images were analysed retrospectively. PET scans were considered positive when diffuse, symmetrical, abnormal “USA” (uptake in supraclavicular area) fat was detected. Results A total of 163 PET images were analysed. Seventy-four PET scans (45%) revealed abnormal FDG uptake in the supraclavicular area. These foci were present on uncorrected and attenuation-corrected images. FDG uptake was identical on all five scans in only five patients. No significant relationship was found between abnormal FDG uptake and outdoor temperature, age or time interval between chemotherapy and PET. Abnormal FDG uptake in the neck seemed to predominantly occur in patients with a low body mass index (p<0.05). Most significant changes in the PET/CT scan results were observed during chemotherapy with docetaxel (p<0.05). When observed, bilateral uptake in the neck was more intense than background uptake (p<0.00001). Conclusion This study shows that FDG uptake in the neck varies as a function of time, that it is unrelated to age or outdoor temperature, and that bilateral uptake is generally intense.     

18F-FDG PET/CT in the evaluation of POEMS syndrome

In POEMS syndrome the identification and biopsy of an osteosclerotic lesion or a lymph node typical of Castleman's disease (CD) is essential to establish the diagnosis and plan appropriate treatment. We report four patients in whom the localisation and identification of diagnostic bone lesions or lymphadenopathies were guided by fluorodeoxyglucose positron emission tomography integrated with computerised tomography (FDG PET/CT). FDG PET/CT identified bone lesions not detected with other techniques in one patient, and revealed hypermetabolic characteristics in bone lesions or adenopathies in the others, thus guiding the diagnostic biopsy in those with hypermetabolism. In conclusion, FDG PET/CT may be useful in detecting and selecting bone lesions and lymph nodes for biopsy in patients with suspected POEMS syndrome.