Determination of Myocardial Viability with ECG-Gated Fluorodeoxyglucose F-18 Positron Emission Tomography

OBJECTIVE: We hypothesize that ECG-gated positron emission tomography (PET) using Fluorodeoxyglucose F-18 (FDG) alone can determine myocardial viability by identifying dysfunctional myocardium with preserved glucose metabolism. We compared the contraction-metabolism pattern of gated FDG PET with the perfusion-metabolism pattern of conventional PET using N-13 ammonia (NH(3)) as a perfusion agent and FDG as a glucose metabolism agent in 21 consecutive patients with chronic coronary artery disease with left ventricular dysfunction (mean ejection fraction 23.6 +/- 7.7%).METHODS: The left ventricle was divided into 17 segments. Uptakes of NH(3) and FDG were scored from absent (0) to normal (4), and wall motion was scored from dyskinesia (-1) to normal (3). Scores were determined by the visual interpretation of the majority of 3 blinded expert readers. Viable myocardium was defined by normal or mildly reduced uptakes of both NH(3) and FDG, perfusion-metabolism mismatch on NH(3)-FDG PET, or normal to mildly reduced uptake of FDG with regional dysfunction on gated FDG PET.RESULTS: Gated FDG PET identified 184 segments as viable, all of which were determined as viable by NH(3)-FDG PET. Among 125 segments identified as nonviable by NH(3)-FDG PET, 76 segments were determined as nonviable by NH(3)-FDG PET. The results provided a positive and negative predictive value of gated FDG PET for the determination of myocardial viability to be 100% and 60.8%, respectively.CONCLUSIONS: Gated FDG PET has a high positive predictive value (100%) for the identification of viable myocardium.     

Evaluation of Rare Tumors with [F-18]Fluorodeoxyglucose Positron Emission Tomography

The purpose of this paper was to evaluate the utility of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) in the clinical assessment of rare tumors. We identified 6 patients over the last 18 months with rare tumors who were referred for PET imaging at the time of initial diagnosis, for tumor surveillance or for posttherapy reevaluation. The PET findings were compared with follow-up clinical data, the results of other imaging modalities and histology. FDG PET correctly detected disease in patients with anaplastic thyroid cancer, pleural mesothelioma, myxoid liposarcoma, malignant fibrous histiocytoma, synovial cell sarcoma and uterine leiomyosarcoma. These findings suggest that PET is useful in the evaluation of a variety of rare tumors both for initial preoperative staging and post-therapy assessment. Further experience with other uncommon tumors is necessary to define the precise role of FDG PET in this clinical setting.     

Hot-Clot Artifacts in the Lung Parenchyma on F-18 Fluorodeoxyglucose Positron Emission Tomography/CT due to Faulty Injection Techniques: Two Case Reports

F-18-fluorodeoxyglucose (FDG) positron emission tomography/CT is an important whole-body imaging tool in the oncology and widely utilized to stage and restage various malignancies. The findings of significant focal accumulation of FDG in the lung parenchyma in the absence of corresponding CT abnormalities are related to the lung microembolism and known as hot-clot artifacts. Herein we present two cases with focal FDG uptake in the lung parenchyma with no structural lesions on the CT scan and discuss the possible mechanisms.     

18F-FDG PET/CT显像发现意外高代谢原发恶性肿瘤的初步研究

目的研究18-氟脱氧葡萄糖正电子发射计算机断层扫描(18F-FDG PET/CT)显像发现意外高代谢原发恶性肿瘤的价值。方法回顾性分析2007年7月至2010年12月共4896例18F-FDG PET/CT显像结果,其中已知或可疑恶性肿瘤患者3967例,健康体检者929名。意外高代谢病灶定义为新发现的与原发或可疑肿瘤无关的、或在健康体检者发现的18-氟脱氧葡萄糖(18F-FDG)代谢异常增高灶。通过病理学检查、临床随访等进一步明确诊断。结果共发现可疑意外高代谢病灶245个,其中53个病灶经病理证实为意外恶性原发肿瘤,依次为甲状腺癌4个、肺癌6个、结直肠癌17个、胃癌8个、前列腺癌6个、胰腺癌2个、乳腺癌2个、其他8个。结论 18F-FDG PET/CT显像上意外高代谢病灶往往提示恶性病灶,有必要进一步明确病理,调整治疗方案,从而改善患者预后。     

Prognostic Value of SUVmax Measured by Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography in Patients with Gallbladder Cancer

Objective

The aim of this study is to investigate the prognostic value of F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET)/computed tomography (CT) in gallbladder cancer patients.

Methods

From June 2004 to June 2010, a total of 50 patients with gallbladder cancer who underwent diagnostic staging with F-18 FDG PET/CT following curative or palliative treatments were retrospectively evaluated. For the analysis, all patients were classified by age, sex, maximum standardized uptake value (SUVmax), lymph node (LN) or distant metastasis, serum level of CA19-9 and CEA, type of treatment and American Joint Committee on Cancer (AJCC) stage.

Results

The median survival for the 50 patients was 245 days and the median SUVmax in PET/CT was 8.3 (range, 0-19.7). Patients with SUVmax < 6 survived significantly longer than patients with SUVmax ≥ 6 (median 405 days vs 203 days, p = 0.0400). On Kaplan-Meier analysis, SUVmax (p = 0.0400), stage (p = 0.0001), CA19-9 (p = 0.013), CEA (p = 0.006), LN metastasis (p = 0.0001), distant metastasis (p = 0.0020), type of treatment (p = 0.0001) were significantly associated with overall survival. Multivariate analysis study revealed that the patients with lower SUVmax measured from initial staging PET/CT (p = 0.0380), no LN metastasis (p = 0.0260), a lower stage (p = 0.026) and curative treatment (p = 0.0005) had longer survivals.

Conclusions

The present study shows that SUVmax on F-18 FDG PET/CT can provide prognostic information in patients with gallbladder cancer.     

Prognostic value of SUVmax measured by Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography in Patients with Pancreatic Cancer

Purpose

Recent studies have been conducted on the relationship between fluorodeoxyglucose (FDG) uptake in F-18 FDG PET/CT and prognosis in patients with pancreatic cancer, but these studies have been carried out in small numbers of patients. The aim of this retrospective study was to determine in a large number of patients whether glucose metabolism as assessed by F-18 FDG PET/CT provides prognostic information independent of established prognostic factors in patients with pancreatic cancer.

Methods

We reviewed retrospectively the medical records of 165 patients (men 105, women 60, mean age 67 ± 10 years) with a diagnosis of pancreatic cancer that had undergone F-18 FDG PET/CT as part of a pretreatment workup from January 2004 to December 2009. Subsequently, all patients underwent surgery, cyberknife, radiotherapy, and/or chemotherapy. For the analysis, patients were classified by age, demographic data, maximum standardized uptake value (SUVmax), size, location, serum level of CA19-9, type of treatment, and AJCC stage. The relationship between FDG uptake and survival was analyzed using the Kaplan-Meier with log-Rank test and Cox’s proportional-hazard regression methods.

Results

Median survival for all 165 study subjects was 290 days and median SUV by PET/CT was 5.8 (range: 0–25.1). Patients were allocated to high (> 4.1) and low (≤4.1) SUV groups, and median survivals of these patients were 229 days and 610 days, respectively, which were significantly different (p < 0.0001). Furthermore, SUVmax was found to be significantly related to survival in each stage, i.e., there were 1267 days in stage I, 440 days in stage II, 299 days in stage III, and 143 days in stage IV (p < 0.0001). The median survival was also found to be significantly related to tumor size (p = 0.001), site (p = 0.0298), serum level of CA19-9 (p = 0.0017), distant metastasis (p < 0.0001), and type of treatment (p < 0.0001). Multivariate analysis study revealed that the patients with a low SUV (p = 0.0298), a lower serum level of CA19-9 (p = 0.0071), a lower stage (p = 0.0017), and no distant metastasis (p < 0.0001) had longer survivals. In addition, SUVmax values were found to have a similar hazard ratio of distant metastasis; it was well known predictor. Furthermore, SUVmax values showed a higher hazard ratio than that of other clinicopathologic predictors.

Conclusion

The present study shows that SUVmax on F-18 FDG PET/CT can provide a prognostic information in patients with pancreatic cancer.     

A Computed Tomography-Based Spatial Normalization for the Analysis of [18F] Fluorodeoxyglucose Positron Emission Tomography of the Brain

Objective

We developed a new computed tomography (CT)-based spatial normalization method and CT template to demonstrate its usefulness in spatial normalization of positron emission tomography (PET) images with [¹⁸F] fluorodeoxyglucose (FDG) PET studies in healthy controls.

Materials and Methods

Seventy healthy controls underwent brain CT scan (120 KeV, 180 mAs, and 3 mm of thickness) and [¹⁸F] FDG PET scans using a PET/CT scanner. T1-weighted magnetic resonance (MR) images were acquired for all subjects. By averaging skull-stripped and spatially-normalized MR and CT images, we created skull-stripped MR and CT templates for spatial normalization. The skull-stripped MR and CT images were spatially normalized to each structural template. PET images were spatially normalized by applying spatial transformation parameters to normalize skull-stripped MR and CT images. A conventional perfusion PET template was used for PET-based spatial normalization. Regional standardized uptake values (SUV) measured by overlaying the template volume of interest (VOI) were compared to those measured with FreeSurfer-generated VOI (FSVOI).

Results

All three spatial normalization methods underestimated regional SUV values by 0.3-20% compared to those measured with FSVOI. The CT-based method showed slightly greater underestimation bias. Regional SUV values derived from all three spatial normalization methods were correlated significantly (p < 0.0001) with those measured with FSVOI.

Conclusion

CT-based spatial normalization may be an alternative method for structure-based spatial normalization of [¹⁸F] FDG PET when MR imaging is unavailable. Therefore, it is useful for PET/CT studies with various radiotracers whose uptake is expected to be limited to specific brain regions or highly variable within study population.     

The ECAT ART Scanner for Positron Emission Tomography. 1. Improvements in Performance Characteristics

The widespread use of positron emission tomography (PET) has been to some extent limited by the cost and complexity of PET instrumentation. Recognition of the wider applicability of clinical PET imaging is reflected in the ECAT ART design, a low cost PET scanner targeted for clinical applications, particularly in oncology. The ART comprises two asymmetrically opposed arrays of BGO block detectors. Each array consists of 88 (transaxial) by 24 (axial) crystals, and the arrays rotate continuously at 30 rpm to acquire a full 3D projection data set. Sensitivity and count rate limitations are key performance parameters for any imaging device. This paper reports on improved performance characteristics of the ART, achieved by operating the scanner with a decreased block integration time, reduced coincidence time window, and collimated singles transmission sources. Compared to the standard ART configuration, these modifications result in both improved count rate performance and higher quality transmission scans.     

[18]Fluorodeoxyglucose Positron Emission Tomography for the Textural Features of Cervical Cancer Associated with Lymph Node Metastasis and Histological Type

Background

In this study, we investigated the correlation between the lymph node (LN) status or histological types and textural features of cervical cancers on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography.

Methods

We retrospectively reviewed the imaging records of 170 patients with International Federation of Gynecology and Obstetrics stage IB–IVA cervical cancer. Four groups of textural features were studied in addition to the maximum standardized uptake value (SUV_max), metabolic tumor volume, and total lesion glycolysis (TLG). Moreover, we studied the associations between the indices and clinical parameters, including the LN status, clinical stage, and histology. Receiver operating characteristic curves were constructed to evaluate the optimal predictive performance among the various textural indices. Quantitative differences were determined using the Mann–Whitney U test. Multivariate logistic regression analysis was performed to determine the independent factors, among all the variables, for predicting LN metastasis.

Results

Among all the significant indices related to pelvic LN metastasis, homogeneity derived from the gray-level co-occurrence matrix (GLCM) was the sole independent predictor. By combining SUV_max, the risk of pelvic LN metastasis can be scored accordingly. The TLG_mean was the independent feature of positive para-aortic LNs. Quantitative differences between squamous and nonsquamous histology can be determined using short-zone emphasis (SZE) from the gray-level size zone matrix (GLSZM).

Conclusion

This study revealed that in patients with cervical cancer, pelvic or para-aortic LN metastases can be predicted by using textural feature of homogeneity from the GLCM and TLG_mean, respectively. SZE from the GLSZM is the sole feature associated with quantitative differences between squamous and nonsquamous histology.