The aim of the study was to assess the agreement between the left ventricular ejection fraction (LVEF) values obtained with IQ-SPECT and those obtained with a conventional gamma camera equipped with ...low-energy high-resolution (LEHR), considered as the method of reference.
Gated-stress MPI using 99mTc-tetrofosmin was performed in 55 consecutive patients. The patients underwent two sequential acquisitions (Method A and B) performed on Symbia-IQ SPECT with different acquisition times and one (Method C) on a Ecam SPECT equipped with LEHR collimators. The values of the different datasets were compared using the Bland-Altman analysis method: the bias and the limits of agreement (LA) were estimated in a head-to-head comparison of the three protocols.
In the (Method A-Method C) comparison for LVEF, the bias was 3.8% and the LAs ranged from − 9.3% to 16.8%. The agreement was still lower between Method B and C, whilst only slightly improved when Methods A and B were compared.
The wide amplitude in LA intervals of about 30% indicates that IQ and LEHR GSPECT are not interchangeable. The values obtained with IQ-SPECT should only be used with caution when evaluating the functional state of the heart.
18F fluorodeoxyglucose positron emission tomography/computed tomography (18F FDG-PET/CT) may be used for tumor staging and prognosis in several tumors but its role in rectal cancer is still debated. ...The aim of the present study was to assess the correlation of baseline 18F FDG-PET parameters with tumor staging, tumor response (tumor regression grade (TRG)), and outcome in a series of patients affected by locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT).
One hundred patients treated with neoadjuvant CRT and radical surgery were enrolled in the present study. Maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) at the baseline 18F FDG-PET were calculated. These PET parameters were correlated with tumor staging, histopathological data (TRG1 vs. TRG2-5 and TRG1-2 vs. TRG3-5), disease-free survival, and overall survival.
SUVmax and SUVmean of primary tumor were statistically associated with T4-stage. SUVmax, SUVmean, and TLG did not result statistically associated with TRG (TRG1 or TRG1-2). MTV resulted statistically associated with TRG1-2 group (OR 2.9; 95% CI 1.2-7.1). Finally, no PET parameter was significantly associated with disease-free or overall survival.
Our results showed that baseline 18F FDG-PET parameters correlated with tumor staging, and only MTV correlated with TRG 1-2. PET parameters failed to predict disease-free and overall survival after treatment completion. The results leave open to further studies the issue of identifying patients suitable for conservative approaches.
To investigate the potential impact of using (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on staging and target volume delineation for patients affected by ...rectal cancer and candidates for preoperative conformal radiotherapy.
Twenty-five patients diagnosed with rectal cancer T3-4 N0-1 M0-1 and candidates for preoperative radiotherapy underwent PET/CT simulation after injection of 5.18 MBq/kg of FDG. Clinical stage was reassessed on the basis of FDG-PET/CT findings. The gross tumor volume (GTV) and the clinical target volume (CTV) were delineated first on CT and then on PET/CT images. The PET/CT-GTV and PET/CT-CTV were analyzed and compared with CT-GTV and CT-CTV, respectively.
In 4 of 25 cases (24%), PET/CT affected tumor staging or the treatment purpose. In 3 of 25 cases (12%) staged N0 M0, PET/CT showed FDG uptake in regional lymph nodes and in a case also in the liver. In a patient with a single liver metastasis PET/CT detected multiple lesions, changing the treatment intent from curative to palliative. The PET/CT-GTV and PET/CT-CTV were significantly greater than the CT-GTV (p = 0.00013) and CT-CTV (p = 0.00002), respectively. The mean difference between PET/CT-GTV and CT-GTV was 25.4% and between PET/CT-CTV and CT-CTV was 4.1%.
Imaging with PET/CT for preoperative radiotherapy of rectal cancer may lead to a change in staging and target volume delineation. Stage variation was observed in 12% of cases and a change of treatment intent in 4%. The GTV and CTV changed significantly, with a mean increase in size of 25% and 4%, respectively.
FDG-PET/CT imaging has an emerging role in staging and treatment planning of various tumor locations and a number of literature studies show that also the carcinoma of the anal canal may benefit from ...this diagnostic approach. We analyzed the potential impact of FDG-PET/CT in stage definition and target volume delineation of patients affected by carcinoma of the anal canal and candidates for curative radiotherapy.
Twenty seven patients with biopsy proven anal carcinoma were enrolled. Pathology was squamous cell carcinoma in 20 cases, cloacogenic carcinoma in 3, adenocarcinoma in 2, and basal cell carcinoma in 2. Simulation was performed by PET/CT imaging with patient in treatment position. Gross Tumor Volume (GTV) and Clinical Target Volume (CTV) were drawn on CT and on PET/CT fused images. PET-GTV and PET-CTV were respectively compared to CT-GTV and CT-CTV by Wilcoxon rank test for paired data.
PET/CT fused images led to change the stage in 5/27 cases (18.5%): 3 cases from N0 to N2 and 2 from M0 to M1 leading to change the treatment intent from curative to palliative in a case.Based on PET/CT imaging, GTV and CTV contours changed in 15/27 (55.6%) and in 10/27 cases (37.0%) respectively. PET-GTV and PET-CTV resulted significantly smaller than CT-GTV (p = 1.2 x 10(-4)) and CT-CTV (p = 2.9 x 10(-4)). PET/CT-GTV and PET/CT-CTV, that were used for clinical purposes, were significantly greater than CT-GTV (p = 6 x 10(-5)) and CT-CTV (p = 6 x 10(-5)).
FDG-PET/CT has a potential relevant impact in staging and target volume delineation of the carcinoma of the anal canal. Clinical stage variation occurred in 18.5% of cases with change of treatment intent in 3.7%. The GTV and the CTV changed in shape and in size based on PET/CT imaging.
The detection of gastrointestinal (GI) involvement in Mantle Cell Lymphoma is often underestimated and may have an impact on outcome and clinical management. We aimed to evaluate whether baseline ...18F-FDG PET/CT presents comparable results to endoscopic biopsy in the diagnosis of GI localizations. In our retrospective cohort of 79 patients, sensitivity and specificity of 18F-FDG PET/CT were low for the stomach, with a fair concordance (
= 0.32), while higher concordance with pathologic results (
= 0.65) was detected in the colorectal tract. Thus, gastric biopsy remains helpful in the staging of MCL despite 18F-FDG PET/CT, while colonoscopy could be omitted in asymptomatic patients. The validation of our data in prospective cohorts is desirable.
Objectives
The purpose of this study was to evaluate the impact on lesion detectability of fast imaging protocols using
18
F-FDG and a 3-dimensional LSO-based PET/CT scanner.
Methods
An ...anthropomorphic thoracic phantom was used simulating the anatomical structures of radioactivity distribution for the upper torso of an underweight patient. Irregularly shaped targets of small dimensions, the zeolites, were located inside the phantom in an unpredictable position for the observers. Target-to background ratios and target dimensions were selected in order to sample the range of detectability. Repeated imaging was performed to acquire PET images with varying emission scan duration (ESD) of 1, 2, 3 and 4 min/bed and background activity concentrations of 10, 5 and 3 kBq/mL in the torso cavity. Three observers ranked the targets and a receiver operating characteristic analysis was performed for each acquisition protocol.
Results
Detection performances improved when passing from a short (ESD = 1 min) protocol to longer (ESD ≥ 2 min) protocols. This improvement was established with adequate statistical significance.
Conclusions
Short image acquisition times of 1 min/bed using
18
F-FDG and the specific scanner model considered in the study lead to reduced lesion detectability and should be avoided also in underweight patients.
Introduction
18
FFluoroestradiol (
18
FFES) PET/CT has been proposed as a tool for detecting the oestrogen receptor density in patients with metastatic breast cancer (BC) non-invasively across all ...disease localizations. However, its diagnostic potential in terms of the detection rate (DR) of metastases is unclear. In this study, we pitted this method against
18
FFDG PET/CT and tried to identify predictors of the diagnostic superiority of the
18
F FES-based method.
Materials and methods
From a multicentre database, we enrolled all patients with metastatic BC who had undergone both
18
FFES PET/CT and
18
FFDG PET/CT. Two readers assessed both images independently and used a patient-based (PBA) and lesion-based analysis (LBA) to calculate the DR. Pathology-related and clinical factors were tested as predictors of
18
FFES PET/CT superiority using a multivariate model.
Results
92 patients, bearing a total of 2678 metastases, were enrolled. On PBA, the DR of
18
FFDG and
18
FFES PET/CT was 97% and 86%, respectively (
p
= 0.018). On LBA, the
18
FFES method proved more sensitive than
18
FFDG PET/CT in lymph nodes, bone, lung and soft tissue (
p
< 0.01). This greater sensitivity was associated with lobular histology, both on PBA (Odds Ratio (OR) 3.4, 95%CI 1.0–12.3) and on LBA (OR 4.4, 95%CI 1.2–16.1 for lymph node metastases and OR 3.29, 95%CI 1.1–10.2 for bone localizations).
Conclusions
The overall DR of
18
FFES PET/CT appears to be lower than that of
18
FFDG PET/CT on PBA. However, the
18
FFES method, if positive, can identify more lesions than
18
FFDG at most sites. The higher sensitivity of
18
FFES PET/CT was associated with lobular histology.
This article reports the results of performance measurements obtained for the lutetium oxyorthosilicate (LSO)-based whole-body PET/CT scanner Biograph 16 HI-REZ with the National Electrical ...Manufacturers Association (NEMA) NU 2-2001 standard. The Biograph 16 HI-REZ combines a multislice (16-slice) spiral CT scanner with a PET scanner composed of 24.336 LSO crystals arranged in 39 rings. The crystal dimensions are 4.0x4.0x20 mm3, and the crystals are organized in 13x13 blocks coupled to 4 photomultiplier tubes each. The 39 rings allow the acquisition of 81 images 2.0 mm thick, covering an axial field of view of 162 mm. The low- and high-energy thresholds are set to 425 and 650 keV, respectively, acquiring data within a 4.5-ns-wide coincidence window.
Performance measurements for the LSO-based PET/CT scanner were obtained with the NEMA NU 2-2001 standard, taking into account issues deriving from the presence of intrinsic radiation.
The results obtained with the NEMA NU 2-2001 standard measurements were as follows: average transverse and axial spatial resolutions (full width at half maximum) at 1 cm and at 10 cm off axis of 4.61 (5.10) mm and 5.34 (5.91) mm, respectively; average sensitivity of 4.92 counts per second per kilobecquerel for the 2 radial positions (0 and 10 cm); 34.1% system scatter fraction; and peak noise equivalent count (NEC) rates of 84.77 kilocounts per second (kcps) at 28.73 kBq/mL (k=1 in the NEC formula; noiseless random correction) and 58.71 kcps at 21.62 kBq/mL (k=2; noisy random correction).
The new integrated PET/CT system Biograph 16 HI-REZ has good overall performance, with, in particular, a high resolution, a low scatter fraction, and a very good NEC response.
Purpose
The present work studies the correlation of (18) F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) standardized uptake value (SUV) with tumor characteristics, ...clinical response and prognosis in a series of anal canal cancer patients treated with chemo-radiotherapy.
Materials and methods
Fifty-five patients were included in the present analysis. PET maximum SUV (SUVmax) of primary tumor was calculated for each patient. The correlation with clinical parameters, tumor response and survival data were analyzed.
Results
SUVmax significantly correlated with T-stage (
p
= 0.01) and histology (
p
= 0.03). Median SUVmax was higher for lesions with partial response (PR, 21/55, 38 %) than for lesions with complete response (CR, 34/55, 62 %) but without statistical significance (
p
= 0.17). The actuarial disease-free survival (DFS) and overall survival (OS) rates were 53.0 and 77.8 % at 2 years and 41.3 and 58.6 % at 5 years, respectively. Median SUVmax did not statistically correlate with clinical response or survival. CR and T1–T2 stage were statistically significant prognostic factors for disease-free survival (
p
< 0.0001 and
p
= 0.02, respectively) and CR was significant also for overall survival (
p
< 0.0001).
Conclusions
Our data suggest that pre-treatment FDG-PET/CT SUVmax cannot directly predict tumor response and survival, but it is strongly associated with tumor characteristics such as primary tumor stage and histology, being the first one of the most important and validated prognostic factors for anal cancer.
Purpose
To assess the presence and pattern of incidental interstitial lung alterations suspicious of COVID-19 on fluorine-18-fluorodeoxyglucose positron emission tomography (PET)/computed tomography ...(CT) (
18
FFDG PET/CT) in asymptomatic oncological patients during the period of active COVID-19 in a country with high prevalence of the virus.
Methods
This is a multi-center retrospective observational study involving 59 Italian centers. We retrospectively reviewed the prevalence of interstitial pneumonia detected during the COVID period (between March 16 and 27, 2020) and compared to a pre-COVID period (January–February 2020) and a control time (in 2019). The diagnosis of interstitial pneumonia was done considering lung alterations of CT of PET.
Results
Overall,
18
FFDG PET/CT was performed on 4008 patients in the COVID period, 19,267 in the pre-COVID period, and 5513 in the control period. The rate of interstitial pneumonia suspicious for COVID-19 was significantly higher during the COVID period (7.1%) compared with that found in the pre-COVID (5.35%) and control periods (5.15%) (
p
< 0.001). Instead, no significant difference among pre-COVID and control periods was present. The prevalence of interstitial pneumonia detected at PET/CT was directly associated with geographic virus diffusion, with the higher rate in Northern Italy. Among 284 interstitial pneumonia detected during COVID period, 169 (59%) were FDG-avid (average SUVmax of 4.1).
Conclusions
A significant increase of interstitial pneumonia incidentally detected with
18
FFDG PET/CT has been demonstrated during the COVID-19 pandemic. A majority of interstitial pneumonia were FDG-avid. Our results underlined the importance of paying attention to incidental CT findings of pneumonia detected at PET/CT, and these reports might help to recognize early COVID-19 cases guiding the subsequent management.
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