Check out our New Publishers' Select for Free Articles

Annals of Nuclear Medicine (v.24, #7)

Importance of gated CT acquisition for the quantitative improvement of the gated PET/CT in moving phantom by Y. Sakaguchi; T. Mitsumoto; T. Zhang; K. Mitsumoto; Y. Tachiya; N. Ohya; M. Sasaki (pp. 507-514).

The aim of this study was to investigate the utility of gated PET/CT and CT attenuation correction (AC) for the quantitation of radioactivity.An ellipse phantom containing six spheres, ranging from 10 to 37 mm in diameter, was filled with 36.7 kBq/mL of F-18. The respiratory motion was simulated by a motor-driven plastic platform to move the phantom with a displacement of 2 cm in the craniocaudal direction at a frequency of 15/min. With the phantom at rest, PET/CT data were acquired and used as a standard (nonmotion). With the phantom in motion, PET data were acquired in both the static and gated modes (sPET and gPET, respectively). Helical CT (HCT), slow CT (SCT), average CT (ACT), and four-dimensional CT (4DCT) were acquired and used to correct attenuation. On both PET and CT images, the maximum radioactivity, dimensions, and CT numbers were measured on the central slices.In nonmotion, recovery coefficients whose spheres were 22 mm or smaller gradually decreased. Regarding motion, the PET counts of the spheres in the static acquisition were lower than those acquired in nonmotion with either type of CTAC (sPET–HCT: −43.8%, sPET–SCT: −51.4%, sPET–ACT: −49.5%). Gated acquisition of PET significantly improved the PET counts (gPET–HCT: −30.1%) (p < 0.05), while additional gated acquisition of CT significantly improved them further (gPET–4DCT: −15.2%) (p < 0.01). The dimensions of sPET were overestimated, but those of gPET were close to the standard values. The SCT significantly overestimated the dimensions, and the water density area decreased (p < 0.01). The 4DCT images were similar to the HCT images.In respiratory motion, PET acquisition in the static mode underestimated the radioactivity and overestimated the dimensions. Neither SCT nor ACT improved these errors. Although PET acquisition in the gated mode improved the quantification of PET/CT images, the additional gated CT acquisition using 4DCT is required for further improvement.

Keywords: Respiration motion; Gated; PET/CT; 4DCT; Attenuation correction

Evaluation of Tourette’s syndrome by ^99mTc-TRODAT-1 SPECT/CT imaging by Hong Liu; Feng Dong; Zhaowei Meng; Benshu Zhang; Jian Tan; Yu Wang (pp. 515-521).

Clinical evidence indicates that the Tourette’s syndrome (TS) is associated with hyperactivity of the dopaminergic system; however, imaging studies of dopamine transporter (DAT) in TS patients remain controversial. In this study, we aimed to study DAT binding capacities in a relatively larger sample of drug-naive patients with TS in comparison with controlled subjects by ^99mTc-TRODAT-1 SPECT/CT imaging. We also aimed to look for any possible correlations between DAT and age, disease duration or tic severity of TS, which have not been thoroughly investigated in previous studies. We tried to provide more evidence for the understanding of the physiopathological mechanism of TS from the molecular imaging perspective.Eighteen drug-naive patients with TS and 8 age- and gender-matched healthy subjects were recruited. Severity of TS was measured with Yale Global Tic Severity Scale. Brain SPECT/CT was performed 2.5 h after injection of ^99mTc-TRODAT-1. Regions of interest were drawn on the striatum including its sub-regions of caudate and putamen. The cerebellum was used as the reference region. DAT uptake ratio was calculated by subtracting the mean counts per pixel in the cerebellum from the mean counts per pixel in the striatum, caudate or putamen and by dividing the result by the mean counts per pixel in the cerebellum. Comparisons of DAT uptake ratios between TS patients and controls, and comparisons in bilateral striatum and sub-regions in TS patients were carried out. Correlation analysis between DAT uptake ratios and clinical data were also conducted.TS patients showed significantly higher uptake of ^99mTc-TRODAT-1 in bilateral striatum in comparison with the controls. There was no group-specific preferential lateralization in striatal uptake. DAT uptake ratios were not correlated with age and tic severity scores, but significant negative correlation with disease duration was found.High level of DAT was demonstrated in drug-naive TS patients compared with normal controls, and it was negatively correlated with TS duration. Therefore, with the extension of the disease duration, certain degree of adaptation might occur in TS patients to compensate for the DAT increase, which suggested that hyper-functional DAT might be involved in the early pathophysiological changes of TS.

Keywords: Dopamine transporter (DAT); ^99mTc-TRODAT-1; Tourette’s syndrome (TS); SPECT/CT

A meta-analysis of ¹⁸F-Fluoride positron emission tomography for assessment of metastatic bone tumor by Ukihide Tateishi; Satoshi Morita; Masataka Taguri; Kazuya Shizukuishi; Ryogo Minamimoto; Masashi Kawaguchi; Takeshi Murano; Takashi Terauchi; Tomio Inoue; E. Edmund Kim (pp. 523-531).

The aim of this study was to assess the diagnostic performance of ¹⁸F-Fluoride positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) compared with bone scintigraphy (BS) planar or BS planar and single photon emission computed tomography (SPECT) in evaluating patients with metastatic bone tumor.We performed a meta-analysis of all available studies addressing the diagnostic accuracy of ¹⁸F-Fluoride PET, ¹⁸F-Fluoride PET/CT, BS planar, and BS planar and SPECT for detecting the metastatic bone tumor. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios, and drew summary receiver operating characteristic curves using hierarchical regression models. We also compared the effective dose and cost-effectiveness estimated by data from the enrolled studies between ¹⁸F-Fluoride PET or PET/CT and BS planar or BS planar and SPECT.When comparing all studies with data on ¹⁸F-Fluoride PET or PET/CT, sensitivity and specificity were 96.2% [95% confidence interval (CI) 93.5–98.9%] and 98.5% (95% CI 97.0–100%), respectively, on a patient basis and 96.9% (95% CI 95.9–98.0%) and 98.0% (95% CI 97.1–98.9%), respectively, on a lesion basis. The Az values of ¹⁸F-Fluoride PET or PET/CT were 0.986 for the patient basis and 0.905 for the lesion basis, whereas those of BS or BS and SPECT were 0.866 for the patient basis and 0.854 for the lesion basis. However, the estimated effective dose and average cost-effective ratio were poorer for ¹⁸F-Fluoride PET or PET/CT than those of BS planar or BS planar and SPECT. ¹⁸F-Fluoride PET or PET/CT has excellent diagnostic performance for the detection of metastatic bone tumor, but the estimated effective dose and average cost-effective ratio are at a disadvantage compared with BS planar or BS planar and SPECT.

Keywords: ¹⁸F-Fluoride; PET; PET/CT

Assessment of VEGF-D expression measured by immunohistochemical staining and F-18 FDG uptake on PET as biological prognostic factors for recurrence in patients with surgically resected lung adenocarcinoma by Lina Zhang; Kotaro Higashi; Yasuhito Ishigaki; Yoshimichi Ueda; Tsutomu Sakuma; Tsutomu Takegami; Manabu Oguchi; Ke Xu; Yasuhiko Ohta; Hiroto Nishida; Hisao Tonami (pp. 533-540).

To assess whether the combined evaluation of vascular endothelial growth factor D (VEGF-D) expression and fluorodeoxyglucose (FDG) uptake correlates with lymph node metastasis and post-operative recurrence in patients with lung adenocarcinoma.Forty-six patients with lung adenocarcinomas, who had undergone both preoperative FDG PET imaging and thoracotomy, were enrolled in this study. The surgically resected tumor specimens were used to assess the protein levels of VEGF-D as measured by immunohistochemical assay.The patients were divided into the following four groups: those who were VEGF-D negative and had low FDG uptake (group I, 3 patients), VEGF-D positive and had low FDG uptake (group II, 20 patients), VEGF-D negative and had high FDG uptake (group III, 13 patients), and VEGF-D positive and had high FDG uptake (group IV, 10 patients). Lymph node metastases were seen only in group III. The 5-year disease-free survival rates were 66.7% in group I, 83.9% in group II, 8.3% in group III, and 64.0% in group IV (p < 0.0001). Thus, patients in group III exhibited the most unfavorable prognoses for recurrence. In multivariate analysis, the combined evaluation of VEGF-D expression and FDG uptake was an independent parameter for post-operative recurrence (p = 0.018).A combination of low VEGF-D expression and high FDG uptake may be a biological indicator of lymph node metastasis and post-operative recurrence in patients with lung adenocarcinoma.

Keywords: VEGF-D; FDG PET; Lung adenocarcinoma; Lymph node metastasis; Recurrence

The clinical application value of PET/CT in adenocarcinoma with bronchioloalveolar carcinoma features by Songtao Liu; Hongxia Cheng; Shuzhan Yao; Caixia Wang; Guangxiu Han; Xin Li; Cheng Liu (pp. 541-547).

The goal of our study was to demonstrate the clinical usefulness of positron emission tomography/computed tomography (PET/CT) for adenocarcinoma with bronchioloalveolar carcinoma (BAC) features, through evaluating the relationship between the intrathoracic lymph node metastases and maximum standardized uptake value (SUVmax), tumor size of the primary tumor and the ratio of BAC component and analysing the correlation of SUVmax, tumor size and the ratio of BAC component.This was a retrospective study. Forty-five patients with focal peripheral lung adenocarcinoma with BAC features were included in this study and underwent the PET/CT scan. Twenty-one patients were women and 24 were men. None of the patients had insulin-dependent diabetes and the serum glucose levels in all patients just before ¹⁸F-FDG was injected were less than 120 mg/dl. The diagnosis of the lesion was made by surgical histopathology.All patients underwent successful surgery, and pathologic examination confirmed that 34 of 118 excised nodal groups in 18 patients were proved to be positive for malignancy. Univariate analysis revealed 3 potential factors related to intrathoracic lymph node metastases: SUVmax (P = 0.002); the ratio of BAC component (P = 0.002); maximum dimension of a tumor on mediastinal window setting images (mDmax, P = 0.025). The maximum dimension of a tumor on pulmonary window setting images (pDmax, P = 0.373) had no significance. A receiver operating characteristic (ROC) curve based on SUVmax, mDmax and the ratio of BAC component was constructed, the area under curve (AUC) was 85.2, 70.3 and 81.5% separately. There was no statistical significance between AUC of SUVmax and AUC of the ratio of BAC component (Z = 0.901, P = 0.368). The AUC of SUVmax and AUC of the ratio of BAC component were significantly higher than AUC of mDmax (Z = 2.112, P = 0.035; Z = 2.016, P = 0.042).The SUVmax and the ratio of BAC component had significant inverse correlation (r = −0.85, P < 0.01). The mDmax and the ratio of BAC component had significant inverse correlation (r = −0.69, P < 0.01). The SUVmax and mDmax had significant correlation (r = 0.60, P < 0.01).PET/CT would be clinically useful for adenocarcinoma with BAC features, because SUVmax obtained by PET/CT can predict the incidence of intrathoracic lymph node metastases at preoperative stages and even for inoperable patients.

Keywords: PET/CT; Fluorine-18-fluorodeoxyglucose; Adenocarcinoma; Bronchioloalveolar carcinoma; Lymph node

FDG-PET/CT in the evaluation of epithelioid hemangioendothelioma of the liver: the role of dual-time-point imaging. A case presentation and review of the literature by Mehmet Tevfik Kitapci; Burcu Esen Akkaş; Ibrahim Gullu; Cenk Sokmensuer (pp. 549-553).

A 46-year-old man with liver lesions referred to us as having “metastases of a malignant mesenchymal tumor” underwent PET/computerized tomography (CT) imaging for the localization of the primary tumor and determination of the extent of disease. No pathological FDG uptake was observed in PET/CT images obtained after 60 min, following FDG injection but delayed PET/CT images demonstrated intense FDG uptake at the liver masses. Since the PET/CT findings were discordant with the initial diagnosis, the pathology specimen was reevaluated and with certain immunohistochemical examinations, the final histopathological decision was changed to epithelioid hemangioendothelioma (EHE). In this report, we discuss the FDG uptake pattern in a patient with hepatic EHE and emphasize the importance of dual-time-point hepatic FDG-PET/CT imaging.

Keywords: Epithelioid hemangioendothelioma; Fluorodeoxyglucose; Positron emission tomography; Liver; Dual-time-point imaging

Intussusception incidentally detected by FDG-PET/CT in a pediatric lymphoma patient by Wichana Chamroonrat; Gang Cheng; Sabah Servaes; Hongming Zhuang (pp. 555-558).

An FDG-PET/CT scan was performed in a 14-year-old boy for the purpose of staging known lymphoma. The PET images identified the primary bowel lymphoma while the corresponding CT portion of the study found the intussusception caused by the lymphoma. The incidental finding of intussusception changed the management regime of the patient. Careful evaluation of both PET and CT images of the PET/CT is essential in providing the best patient care.

Keywords: FDG; PET/CT; Intussusception; Lymphoma; Pediatric

Optimum emission time in deep-inspiration breath-hold PET–CT: a preliminary result by Koichi Miyashita; Ukihide Tateishi; Yuji Nishiyama; Ryogo Minamimoto; Kazuya Shizukuishi; Tomio Inoue (pp. 559-563).

The purpose of this study was to investigate optimum emission time of deep inspiration breath-hold (DIBH) positron emission tomography–computed tomography (PET–CT).We collected 15 PET–CT data sets by adding data of every 10 s and acquisition time ranging from 10 s (1 × 10 s acquisition) to 150 s (15 × 10 s acquisition) for both of DIBH mode and free-breathing condition (continuous mode) in phantom study. The coefficient of variation (CV) of radioactivity concentration was compared to determine optimum emission time of PET–CT. We also compared images of DIBH mode and continuous mode to clarify the influence of diaphragmatic movement in clinical setting.The mean ± SD of CV in DIBH mode was 1236.3 ± 323.1. When compared with the CV at 120 s, the relative error of CV is within 10% at 110 s (0.204), 15% at 100 s (0.212), and 20% at 90 s (0.222), respectively. Optimum emission time greater than 90 s is required to obtain clinically available images in DIBH mode. In the clinical setting, the SUV of the lung base and measurements of uptake show little influence by respiration on DIBH PET–CT.Optimum emission time of DIBH technique greater than 90 s acquisition is preferable for clinical use.

Keywords: PET–CT; Deep-inspiration breath-hold (DIBH); Short time collection; Additional image

Sections

Personal tools

Annals of Nuclear Medicine (v.24, #7)

Sections

Personal tools

Local resources

Annals of Nuclear Medicine (v.24, #7)