فهرست مطالب mehrdad bakhshayeshkaram

This study evaluates scan time reduction using time-of-flight (TOF) PET, when quantitative parameters including volumetric measures are considered.

32 patients were included in the study. The reconstruction parameters for TOF were 2 iterations, 18 and 24 subsets, and for non-TOF was 3 iterations and 18 subsets. A post smoothing filter with FWHM of 5.4 mm and 6.4 mm were used for TOF and 6.4 mm for non-TOF. TOF reconstruction was performed with 2, 2.5 and 3 min/bed position, and 3 min/bed position scan time was applied in non-TOF. Quantitative parameters such as coefficient of variation (COV), signal-to-noise ratio (SNR), lesion-to-background ratio (LBR), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were utilized. Standard uptake value (SUV) was also measured. Different segmentation thresholds were studied.

Improvement in SNR for TOF relative to non-TOF was observed when utilizing 18 subsets, 5.4 mm filter size with 3 min scan time/bed position (P-value<0.0001), and for 18 subsets, 6.4 mm filter size when 2.5- and 3-min scan time/bed positions was applied (P-value≤0.02). Scan time reduction did not illustrate significant variation for the SUVs and lesion size. In all TOF protocols for both TLG and MTV, the measured values decreased with increasing segmentation thresholds, as expected, with significantly more impact for higher thresholds (70%, 75%). Meanwhile, higher values were observed for higher post smoothing filter in each specified threshold. With increasing of the threshold, ΔTLG was increased with more impact for higher post smoothing filter. ΔMTV were -10.10±11.09 (-1.35±8.59) and 0.68±17.51 (12.42±18.90) in 2 min/bed position with 5.4 (6.4 mm post smoothing filter) for threshold of 45% and 75% respectively.

Scan time reduction from 3 to 2 min can be obtained with TOF in comparison with non-TOF, especially when higher segmentation threshold values with higher subset number (24) and 6.4 mm filters are utilized.

 The quality of positron emission tomography/computed tomography (PET/CT) images plays an important role in tumor detection. This imaging method often yields poor-quality images of overweight patients due to the high level of noise, originating from scattering and photon attenuation.

 The point spread function (PSF) is mostly used to enhance the spatial resolution and signal-to-noise ratio (SNR); however, it is known to increase the edge artifacts. The time-of-flight (TOF) principle can reduce edge artifacts in PSF modeling and improve lesion detection, especially in the thorax. The present study aimed to assess these two new techniques by applying different reconstruction parameters.

 An in-house phantom with an inner diameter of 35 cm was used for the simulation of overweight patients. Lesion-to-background ratios (LBRs) of 2: 1 and 8: 1, as well as background activity concentrations of 3 and 5 kBq/cc, were considered in this study. The list-mode data were reconstructed with various reconstruction protocols, numbers of subsets, and filter sizes. Quantitative analyses, including the coefficient of variation (COV), SNR, and recovery coefficient (RC), were also carried out. Moreover, box-and-whisker plots were performed.

 At LBR of 2: 1, by changing the protocol from ordered subset expectation maximization (OSEM) to OSEM + PSF + TOF, the median value of SNR for 13-mm lesions (37 mm) increased by 39.25% and 53.45% (42.22% and 56.21%), at background activity concentrations of 3 and 5 kBq/cc respectively. However, at LBR of 8: 1, the corresponding values were 33.22% and 48.94% (40.22% and 52.15%) at background activity concentrations of 3 and 5 kBq/cc respectively.

 The TOF protocols were strongly recommended for both background activity concentrations at LBR of 2: 1 and for the low background activity concentration at LBR of 8: 1, especially when using smaller filter sizes. Moreover, subset numbers of 18 and 24 were appropriate for all protocols. However, a smaller subset number was suitable when a low background activity concentration and a smaller filter size were applied, especially at a lower LBR.

 Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan is employed for initial staging and restaging of esophageal cancer patients.

 The present study aimed to assess the value of a semi-quantitative parameter of 18F-FDG PET/CT scan, that is, maximum standardized uptake value (SUVmax), to determine its correlation with patient survival in two subtypes of esophageal cancer, including squamous cell carcinoma (SCC) and adenocarcinoma.

 This cross-sectional study was performed on patients with esophageal SCC and adenocarcinoma, undergoing 18F-FDG PET/CT scan for initial staging before any treatment. The 18F-FDG PET/CT semi-quantitative parameter (SUVmax) was determined by reviewing the PET/CT images. The patients were reevaluated using 18F-FDG PET/CT scan for restaging within 12 - 24 months.

 No significant difference was observed in the SUVmax values of the primary tumor, metastatic lymph nodes, or distant metastasis between the adenocarcinoma and SCC groups, regardless of response to treatment. Similarly, no significant association was found between the short-term survival of patients with adenocarcinoma and the SUVmax values of the primary tumor, metastatic lymph nodes, or distant metastasis. Based on the survival curve, one- and two-year survival rates were estimated at 75% and 63.9% in patients with SCC and at 80% and 60% in patients with adenocarcinoma, respectively. In the SCC group, a significantly higher SUVmax was detected in deceased patients with distant metastatic lesions compared to cancer survivors. According to the area under the ROC curve, the SUVmax of metastatic lesions showed high potential for predicting the mortality of SCC patients.

 The assessment of SUVmax in distant metastatic lesions by 18F-FDG-PET/CT may help predict the survival of patients with esophageal SCC. However, 18F-FDG-PET/CT findings were not associated with the survival of esophageal adenocarcinoma; therefore, further evaluations on a larger sample size and a longer follow-up are required.

Melanoma is one of the most serious types of skin cancer and one of the leading causes of cancer-related mortality worldwide.

This study aimed to investigate the association between 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan findings and the pathological characteristics of primary tumors in patients with malignant melanoma.

 

In this cross-sectional study, the baseline data of 103 patients with cutaneous or mucosal melanoma (stage III or IV) were recorded, and tumor characteristics and PET/CT scan findings were analyzed. The association between each pathological finding and PET/CT results was also investigated.

Patients without a free margin had a significantly higher mean standardized uptake value (SUVmax) of lung metastasis compared to patients with a free margin (3.12 vs. 1.69; P = 0.047). Also, patients with ulceration had a significantly higher mean SUVmax of lung metastasis compared to patients without ulceration (3.28 vs. 1.81; P = 0.041). Based on the results, increased primary tumor thickness was associated with a higher SUVmax of lung metastasis. However, there was no significant association between the metastasis type (single vs. multiple) and free margin, ulceration, or Ki-67 protein. The mean SUVmax of lung metastasis was significantly higher in mucosal melanoma compared to cutaneous melanoma. However, the mean SUVmax values of other metastases (bone, liver, and lymph nodes), even the primary lesion itself, were not significantly different between cutaneous melanoma and mucosal melanoma.

The primary tumor margin status, ulceration, tumor thickness, primary tumor location (cutaneous vs. mucosal), and the presence of lung metastasis were significantly associated with PET/CT scan findings.

The use of 68Ga-PSMA PET/CT scan has recently received particular attention in the evaluation of prostate cancer patients.

The present study aimed to evaluate the relationship between the PSA level, Gleason score, and 68Ga-PSMAPET/CT findings in prostate cancer patients.

In this cross-sectional study, 80 male patients with a definitive diagnosis of prostate cancer, who were candidates for 68Ga-PSMA PET/CT scan for both initial staging and restaging, were included. Restaging indicated biochemical recurrence, which refers to a detectable level of PSA after being documented undetectable following a definitive primary treatment. All prostate cancer patients, who were not initially treated with a definitive therapy, were excluded from the study. A cutoff value ≥ 4 was considered significant for SUVmax to differentiate benign from malignant 68Ga-PSMA-avid lesions. Any 68Ga-PSMA uptake outside the prostate bed, especially in the lymph nodes, bones, and visceral organs, was considered metastatic.

Comparison of the PSA level between two subgroups with and without metastasis demonstrated a higher PSA level in patients with metastatic abdominal lymph nodes and a slightly higher PSA level in patients with metastatic pelvic lymph nodes. No significant correlation was found between the Gleason score and the total PSA. There was also no significant association between the level of PSA and the type of Lymph node involvement (single or multiple) in different involved areas. Besides, there was no significant correlation between the SUVmax and the level of PSA and the Gleason score in different involved areas.

The SUVmax value in 68Ga PSMA PET/CT scan provides a reliable predictor for neither the grade of prostate cancer, nor the metastatic status associated with cancer progression. The measurement of total PSA may predict metastasis to the abdominal and pelvic lymph nodes caused by prostate cancer.

This study aimed to investigate the impact of image preprocessing steps, including Gray Level Discretization (GLD) and different Interpolation Algorithms (IA) on 18F-Fluorodeoxyglucose (18F-FDG) radiomics features in Non-Small Cell Lung Cancer (NSCLC).

One hundred and seventy-two radiomics features from the first-, second-, and higher-order statistic features were calculated from a set of Positron Emission Tomography/Computed Tomography (PET/CT) images of 20 non-small cell lung cancer delineated tumors with volumes ranging from 10 to 418 cm3 regarding five intensity discretization schemes with the number of gray levels of 16, 32, 64, 128, and 256, and four Interpolation algorithms, including nearest neighbor, tricubic convolution and tricubic spline interpolation, and trilinear were used. Segmentation was based on 3D region growing-based. The Intraclass Correlation Coefficient (ICC), Overall Concordance Correlation Coefficient (OCCC), and Coefficient Of Variations (COV) were calculated to demonstrate the features' variability and select robust features. ICC and OCCC < 0.5 presented weak reliability, ICC and OCCC between 0.5 and 0.75 illustrated appropriate reliability, values within 0.75 and 0.9 showed satisfying reliability, and values higher than 0.90 indicate exceptional reliability. Besides, features with less than 10% COV have been selected as robust features.

All morphology family (except four features), statistic, and Intensity volume histogram families were not affected by GLD and IA. And the rest of them, 10 and 61 features showed COV ≤ 5% against GLD and IA, respectively. Ten and 80 features showed excellent reliability (ICC values greater than 0.90) against GLD and IA. Eight and 60 features showed OCCC≥0.90 against GLD and IA, respectively. Based on our results Inverse difference normalized and Inverse difference moment normalized from Grey Level Co-occurrence Matrix (GLCM) were the most robust features against GLD and Skewness from intensity histogram family and Inverse difference normalized and Inverse difference moment normalized from GLCM were the most robust features against IA.

Preprocessing can substantially impact the 18F-FDG PET image radiomic features in NSCLC. The impact of gray level discretization on radiomics features is significant and more than Interpolation algorithms.

Pulmonary lymphangioleiomyomatosis (LAM) is an uncommon disease principally affecting women during childbearing years and eventually leading to progressive respiratory failure. Lung transplantation is a viable option for patients with end-stage disease. LAM-related complications remain common, but recurrence of LAM following allograft transplantation is rare. We present a 25-year-old woman who presented with progressive dyspnea five years after bilateral lung transplantation for end-stage LAM. Histological examination of transbronchial lung biopsy sample confirmed recurrent LAM. We changed cyclosporine to sirolimus and she is currently being considered for re-transplantation.

The aim of the present study was to investigate the added value of F-18 fludeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) compared with conventional imaging modalities for the evaluation of locoregional and distant sites of recurrence in breast cancer patients.

From May 2013 to September 2016, 109 patients with suspected recurrent breast cancer who underwent conventional imaging and F-18 FDG PET/CT with an interval of 6 weeks were consecutively enrolled (mean age: 52.66 years; range: 29-79). Histopathologic results and clinical follow up based on the gold-standard imaging modality or serial imaging were considered as the reference for verification of F-18 FDG PET/CTfindings.

Of 109 patients, 81 were found to have at least one site of recurrence (74.31%). Local recurrence was correctly identified in 32/32 patients following PET/CT, which was higher than that on conventional imaging (20/32, 62.5%). PET/CT detected 27 additional nodal metastases compared with conventional imaging (59 vs. 32, 45.76%), most frequently in the hilar/mediastinal region (n=27), followed by the supraclavicular lymph nodes (n=20, 62.5%), internal mammary lymph nodes (n=6, 18.77%), and axillary basin (n=6, 18.77%). Additional sites of distant metastasis were identified in 41 patients (37.61%) following F-18 FDG PET/CT imaging, 48.78% of which were localized in the skeletal system (n=20), 21.95% in the liver (n=9), 12.19% in the lungs (n=5), 12.19% in the brain (n=5), and 4.87% in the adrenal glands (n=2).

F-18 FDG PET/CT serves as a useful supplement to conventional imaging techniques by identifying additional sites of disease recurrence in patients with breast cancer, which may change the preferred treatment strategy, particularly in regions that are not routinely evaluated by conventional imaging.

Diagnosis of coronavirus disease 2019 (COVID-19) can be challenging, especially when the real time quantitative reverse transcription polymerase chain reaction (RT-PCR) is not available or it is negative. In this study, we evaluated imaging and laboratory findings in a group of patients with a multidisciplinary diagnosis of COVID-19 pneumonia.

A total of 163 patients with a clinical diagnosis of COVID-19 pneumonia admitted to a specialised respiratory centre in Tehran, Iran were enrolled in this study. The distribution and characteristics of presenting radiological and laboratory findings were evaluated and the relationship to the outcome was investigated.

RT PCR was positive in 92 patients. The diagnosis of COVID-19 in RT-PCR negative patients was made on clinical and radiological grounds (n=71). Also, 24 (14.7%) patients died. The common computed tomography (CT) scan findings included ground-glass (94%) and consolidating opacification (12%), mainly in the lower lobes (90%). Peripheral and central lung changes were observed in 90% and 52% of patients, respectively. Lymphopenia, positive CRP, and raised LDH were present in 32%, 65%, and 96% of cases, respectively. A raised LDH of >500U/L was the best predictor of death in these patients (R2=0.6623; OR=24.4). Other markers of outcome were male gender, age (>50 years), lymphopenia, and severe CXR changes.

Diagnosis of COVID-19 can be challenging, and a multidisciplinary approach is often needed. Whilst RT-PCR is the standard diagnostic test, a negative test should be interpreted with caution. Blood tests and imaging can be useful in the diagnosis, monitoring, and risk assessment in patients with COVID-19.

This study aimed to compare the recurrence rate of breast cancer between women treated with breast-conserving therapy (BCT) with/without radiotherapy and those treated with total mastectomy using 18F-fluorodeoxyglucose 18 positron emission tomography/computed tomography (F-FDG PET/CT).

The current study retrospectively included 588 patients suffering from breast cancer who had been referred to the PET/CT department of Masih-eDaneshvari Hospital in Tehran between April 2013 and September 2019. Data of all female patients with breast cancer were extracted from the recorded hospital files. Based on the treatment plan, patients were divided into two groups: BCT with/without radiotherapy (n=168) and total mastectomy (n=420). Local, 18 locoregional, and distant metabolically active lesions were determined in F-FDG PET/CTand compared between groups.

BCT and total mastectomy were comparable regarding local (28.5% vs. 25.7%, P=0.200) and locoregional (21.4% vs. 22.8%, P=0.712) recurrence, while distant recurrence was significantly higher with total mastectomy (88.5% vs. 64.2%, P<0.001). Also, lymph node invasion (42.9% vs. 60%m P<0.001) and positive PET/CT(78.5% vs. 88.5%, P=0.002) were significantly higher with total mastectomy. According to multivariate analysis, age, clinical stage, and positive margin are independently correlated with the rate of distant metastasis.

According to our analysis, breast-conserving therapy could be a suitable choice of surgery in selected patients since local and locoregional recurrence rate did not significantly differ between patients who underwent breastconserving surgery compared to those who were treated with total mastectomy. Higher rate of distant metastasis in patients with total mastectomy seems to be influenced by many confounding variables such as age, higher stage of diagnosis and positive margin rather than type of surgery.

An initial evaluation of non-small cell lung cancer (NSCLC) patients with 18F- fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan can modify treatment planning. We investigated the clinical significance of FDG PET/CT quantitative parameters (QPs) in NSCLC patients. We included 125 NSCLC patients for initial staging FDG PET/CT scan. The primary tumor (T), regional lymph node metastases (N), and distant metastases (M) were evaluated on FDG PET/CT images. QPs, including standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated separately for each T, N, and M lesion and also for the whole body. Statistical analysis through SPSS version 22 was used to evaluate the clinical significance of PET/CT QPs concerning primary tumor pathology characteristics, initial tumor stage, and patient’s prognosis. We followed the patients for 19.28 (±11.42) months. Considering primary tumor pathology, there was a significant difference in FDG PET/CT QPs, including primary tumor SUVmax (p=0.00), metastases SUVmax (p=0.014), whole-body MTV (p=0.045), and whole-body TLG (p=0.002). There was also a significant difference in QPs, including primary tumor SUVmax (p=0.00) and regional lymph node metastases SUVmax (p=0.048) when accounting for tumor initial stage. There was a significant prognostic value for the whole-body TLG (p=0.01) and a cut-off point of 568 was reached to differentiate better versus worse survival outcome. We demonstrated a statistically significant difference in FDG PET/CT QPs when accounting for primary NSCLC pathology characteristics and initial stage, as well as patient’s prognosis, and recommend incorporating QP values into clinical PET/CT reports.

Computed tomography (CT) scan plays an important role in the early diagnosis of coronavirus disease (COVID-19) pneumonia. In resource-limited regions with limited availability of polymerase chain reaction (PCR) kits, CT findings, together with appropriate clinical parameters, are used to establish an accurate diagnosis. However, since the radiological findings are non-specific, the CT features may overlap with the findings of several other categories of pulmonary diseases. Diagnosis based on radiological features can be especially challenging in the presence of a comorbid lung disease. This study aimed to describe the radiological findings of a wide spectrum of lung pathologies, with emphasis on their similarities with the common presentations of COVID-19 pneumonia.

Chest computed tomography (CT) scan has been used widely to diagnose COVID-19 in Iran.

To trace the footsteps of COVID-19 in Iran by exploring the trend in using chest CT scans and its economic impact on radiology departments.

In this cross-sectional study, the number of imaging examinations from 33 tertiary radiology departments in 9 large cities of Iran was collected from September 23, 2019 to March 20, 2020 (Months 1 to 6) and the corresponding months in 2018–2019.

A 50.2% increase was noted in the chest CT scan utilization in 2019–2020 compared to 2018–2019. This increase was +15%, +15%, +27%, +2%, +1% in Months 1–5 of 2019–2020, respectively. In Month 6 of 2019–2020, a 251% increase in the acquisition of chest CT scans was observed compared to the Month 6 of 2018–2019. Following negative balance of revenue from Month 1 to 5 with respect to the inflation rate, the total income in Month 6 was further 1.5% less than the same Month in 2018–19.

The observed peak in chest CT utilization in Month 3 prior to the surge in Month 6 could be explained by the seasonal influenza. However, unawareness about an emerging viral disease, i.e. COVID-19, might have underutilized chest CT in Months 4 and 5 before the official announcement in Month 6. The unbalanced increase in the workload of radiology departments in the shortage of cardiothoracic radiologists with the simultaneous decrease in income initiated a vicious cycle that worsened the economic repercussions of the pandemic.

Computed tomography (CT) imaging has quickly found its place as a beneficial tool in the detec-tion of coronavirus disease 2019 (COVID-19). To date, only a few studies have reported the distribution of lunglesions by segment. This study aimed to evaluate the lobar and segmental distribution of COVID-19 pneumo-nia based on patients’ chest CT scan.

This was a retrospective study performed on 63 Iranian adultpatients with a final diagnosis of COVID-19. All patients had undergone chest CT scan on admission. Demo-graphic data and imaging profile, including segmental distribution, were evaluated. Moreover, a scoring scalewas designed to assess the severity of ground-glass opacification (GGO). The relationship of GGO score with age,sex, and symptoms at presentation was investigated.

Among included patients, mean age of patientswas 54.2±14.9 (range: 26 - 81) years old and 60.3% were male. Overall, the right lower lobe (87.3%) and theleft lower lobe (85.7%) were more frequently involved. Specifically, predominant involvement was seen in theposterior segment of the left lower lobe (82.5%). The most common findings were peripheral GGO and consol-idation, which were observed in 92.1% and 42.9% of patients, respectively. According to the self-designed GGOscoring scale, about half of the patients presented with mild GGO on admission. GGO score was found to beequally distributed among different sex and age categories; however, the presence of dyspnea on admission wassignificantly associated with a higher GGO score (p= 0.022). Cavitation, reticulation, calcification, bronchiecta-sis, tree-in-bud appearance and nodules were not identified in any of the cases.

COVID-19 mainlyaffects the lower lobes of the lungs. GGO and consolidation in the lung periphery is the imaging hallmark inpatients with COVID-19 infection. Absence of bronchiectasis, solitary nodules, cavitation, calcifications, tree-in-bud appearance, and reversed halo-sign indicates that these features are not common findings, at least in theearlier stages.

The effect of various environmental and intrinsic stimulators on the development of brown adipose tissue (BAT) has been widely investigated by PET-based researches. However, evidence regarding the influencing factors on the level of BAT metabolic activity is scarce.
The aim of the present study was to evaluate the frequency of cancer-related characteristics in addition to anthropometrics and demographics in BAT-bearing cancer patients at 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan and any correlation between the level of BAT metabolic activity and the influencing factors.
Patients and Reports from a total of 3762 F-18 FDG PET/CT scans were retrospectively reviewed to identify BAT-bearing cancer population. Demographic, anthropometric and cancer related characteristics were recorded. Maximum standardized uptake values (SUVmax) was measured separately for each anatomical region. Descriptive quantitative variables were expressed as either frequency or mean. Independent T test, Mann-Withney U test, Pearson correlation coefficients, one-way analysis of variance and linear regression test (IBM SPSS version 23) were used as appropriate (P value Sixty-two F-18 FDG PET/CT studies demonstrated BAT related 18-F FDG uptake (1.6%, 32% male, 68% female, P = 0.007, mean age 22.9). Lymphoma (43.5%) and treatment response evaluation (54.54%) were the most frequent type of cancer and reason for referral, respectively. Most patients were in status partial or complete metabolic response to treatment. Fifty-four point eight percent of patients had at least one metabolically active cancer-related lesion. BAT detection rate was higher in females in all adult age groups, younger age ( The present study provided evidence for age and chemotherapeutic agents on the level of BAT metabolism. In addition, there is a suggestion for different pathways involved in BAT development and regulation of the level of metabolic activity.

Evolution of individualized radiosurgical therapeutic methods for brain metastasis as an ominous prognostic finding may encourage a more extensive application of neuroimaging in patients with extracerebral cancer. The aim of the present study was to investigate the added value of brain-included 18 F FDG PET/CT acquisition protocol based on primary cancer type and clinical indication.
A retrospective review was performed on 3945 18 F FDG PET/CT reports of patients with extra-cerebral cancer underwent brain-included PET/CT study. Cerebral lesions suggestive of brain metastasis were subsequently verified by MRI, MRIㄔ, surgical pathology and a 1-year clinical formal follow up. The detection rate of new brain metastasis and related impact on disease status were then investigated in each cancer type based on clinical indication.
Of a total 3933 eligible patients, 44 (1.12%) were finally verified to have new cerebral metastasis. The most common primary sources were lung cancer (19/385, 4.93%), cancer of unknown primary (CUP) (5/168, 2.97%) and breast cancer (8/468, 1.71%). The most common clinical indications were initial staging (17/44, 43.1%) and restaging (19/44, 36.4%). Change in disease status occurred in 12 out of 44 patients (27.3%), more frequently occurred in lung cancer (n=4), in all indications and breast (n=3) cancers at restaging (n=7, 43.8%).
PET/CT acquisition protocol study may be best optimized based on the type of primary cancer and timing of evaluation. Brain-included field of view may be recommended for lung cancer regardless the clinical indication, cancer of unknown primary and breast cancer at restaging.

Breast incidental lesion at 18 F FDG PET/CT are occasionally encountered in cancer patients, which may represent a second primary malignancy. The aim of the present study was to investigate the diagnostic performance of PET metabolic parameters to characterize breast incidentaloma.
All the images of patients with cancers other than breast with breast incidental lesion underwent PET/CT scan at Masih Daneshvari Hospital between May 2012 and May 2016 were retrieved and reviewed. SUVmax, SUVmean, MTV and TLG in addition to associated morphologic features on CT and demographics were recorded and correlated with final diagnosis defined by histophatologic confirmation or an at least 1-year clinical formal follow up.
Of a total 58 from 51 patients (51/5029, 1.01%), 10 (19.60%) were histopathologically verified as second primary breast cancers. There was a statistically significant difference in SUVmax, SUVmean, MTV and TLG between benign and malignant group (1.64 vs. 5.32 (p=0.009), 1.34 vs. 3.69 (p=0.027), 0.96 vs. 2.62 (p=0.035), 1.54 vs 8.89 (p=0.006). Using cut off 2, 1.35, 1.16 and 1.75, sensitivity and specificity of SUVmax, SUVmean, MTV and TLG were calculated as 77% and 62%, 92% and 66.5%, 77% and 75% 77% and 67%, respectively.
Despite a significantly higher value in malignant breast incidental lesion, PET-derivative metabolic parameters provided only modest sensitivity and specificity and hence may not be considered as the sole criteria for risk stratification in this clinical setting.

The most important advantage of positron emission tomography/computed tomography (PET/CT) imaging is its capability of quantitative analysis. The aim of the current study was to choose the proper standardized uptake value (SUV) threshold, when the time-of-flight (TOF) and point spread function (PSF) were used for respiratory artifact reduction in the liver dome in a new-generation PET/CT scanner.
The current study was conducted using a National Electrical Manufacturers Association International Electrotechnical Commission body phantom, with activity ratios of 2:1 and 4:1. A total of 27 patients, with respiratory artifacts in the thorax region, were analyzed. PET images were retrospectively reconstructed using either a high definition (HD) PSF (i.e., a routine protocol) algorithm or HD㴡繌 (PSF䳡; i.e., to reduce the respiratory artifact) algorithms, with various reconstruction parameters. The SUVmax and SUVmean, at different thresholds (i.e., at 45%, 50%, and 75%), were also assessed.
Although in comparison to the routine protocol a higher SUV was observed when using the PSF䳡 method, this approach was used to reduce the respiratory artifact. The appropriate threshold for SUV was strongly related to the lesion size, reconstruction parameters, and activity ratio. The mean of the relative difference between PSF䳡 algorithm and routine protocol for SUVmax varied from 10.58±14.99% up to 35.49±32.60% (which was dependent on reconstruction parameters).
In comparison with other types of SUVs, the SUVmax value illustrated its significant overestimation, especially at the 4:1 activity ratio. The poor agreement between SUVmax and SUV50% was also observed. When the TOF and PSF are utilized to reduce respiratory artifacts, the SUV50% can be an accurate semi-quantitative parameter for PET/CT images, for all lesion sizes. For smaller lesions, however, a smaller filter size was required to observe an accurate SUV.

PET/CT scan has an emerging role in head and neck oncology with a few well-established indications, including: detection of unknown primary tumor site, tumor staging, radiotherapy planning, treatment response assessment and detection of recurrent disease. The purpose of this study is reporting PET/CT findings in head and neck cancer patients to emphasize its role in head and neck oncology.
In a retrospective study, we reviewed our PET/CT database and found 94 patients with primary head and neck cancer. This is a descriptive report of PET/CT scan findings in head and neck cancer patients referred to Masih Daneshvari hospital, Tehran, Iran between 2013 and 2016.
The most common primary tumor sites were oral cavity (27%) and nasopharynx (22%). The most common indication for referral was tumor restaging (76%) including treatment response evaluation and differentiation between recurrence and post-treatment fibrosis. In 60% of patients with negative primary tumor site, PET/CT was able to detect evidence of regional or distant metastasis. PET/CT was able to localize the primary tumor site in 66% of patients with unknown primary tumor site. We also had 19 patients with primary head and neck cancer referred for initial staging, demonstrating evidence of metastasis in 66% of all cases.
Most patients are referred for restaging and demonstrate evidence of regional or distant metastasis with significant value for further treatment planning. Providing insurance coverage and familiarizing referring physicians about correctindications of this relatively new diagnostic modality will be to the best interest of head and neck cancer patients in the long run.

PET/CT scan has emerging role in head and neck oncology with a few well-established indications, including: detection of unknown primary tumor site, tumor staging, radiotherapy planning, treatment response assessment and detection of recurrent disease. The purpose of this study is reporting PET/CT findings in head and neck cancer patients to emphasize on its role in head and neck oncology.
We reviewed our PET/CT date-base retrospectively and found 94 patients, referred with primary head and neck cancer. This is a descriptive report of PET/CT scan findings in head and neck cancer patients referred to MasihDaneshvari hospital since 2013 to 2016.
The most common primary tumor sites were oral cavity (27%) and nasopharynx (22%). The most common indication for referral was tumor restaging (76%) including treatment response evaluation and differentiation between recurrence and post-treatment fibrosis. In 60% of patients with negative primary tumor site, PET/CT was able to detect evidence of regional or distant metastasis. PET/CT was able to localize the primary tumor site in 66% of patients with unknown primary tumor site. We had also 19 patients with primary head and neck cancer referred for initial staging, demonstrating evidence of metastasis in 66.2% of all cases.
Most patients are referred for restaging and demonstrate evidence of regional or distant metastasis with significant value for further treatment planning. Providing insurance coverage and familiarizing referring physicians about appropriate indications of this relatively new diagnostic modality will be to the best interest of head and neck cancer patients in long term.

The present study aimed at investigating the influence of cancer related characteristics in association with environmental factors and patients demographics and on the prevalence of brown adipose tissue at 2-deoxy-2-[18F] fluoro-Dsglucose (18F-FDG) as well as the level of metabolic activity.
A total 3762 [18 F] DG PET/CT scans were retrospectively reviewed to identify BAT related [18 F] DG uptake. Demographics, anthropometrics, outdoor temperature, daylight exposure in addition to cancer related characteristics including type of cancer, reason for referral, history of recent treatment, the presence of malignant lesion were recorded. Anatomical distribution of FDG detectable BAT and related SUVmax were also determined. Control groups consisted of patients without FDG detectable BAT was randomly selected and matched for age, gender and mean outdoor temperature for all groups and for type of cancer, reason for referral and presence of active disease, as appropriate. Descriptive quantitative variables were expressed as either frequency or mean. Independent T test, Mann-Withney U test, Pearson correlation coefficients, one-way analysis of variance and linear regression test (SPSS ver.23) were used as appropriate (P value One-hundred eighteen studies were recognized to demonstrate foci of FDG BAT uptake (3.1%, mean age: 22.7 years). There were statistically significant higher rate of BAT occurrence in female, younger patients, normal/low BMI and Body Fat-based categorical weight, lower temperature and shorter daylight duration. In the context of cancer related characteristics, lymphoma and evaluation of treatment response were found as the most prevalent cancer type and reason for referral, respectively. Univariate analysis demonstrated strong correlation between the prevalence of FDG-detectable BAT and associated metabolic activity and age, gender, BMI and BF-based categorical weight, daylight as well as the nonactive underlying malignancy and recent history of treatment. Multivariate analysis revealed age, gender, daylight duration and recent history of treatment as independent influencing factors on BAT recruitment and the level of metabolic activity.
Recent treatment, in addition to age, gender and daylight duration were proved as strong independent determinants on BAT development and the level of metabolic activity at [18 F] DG PET/CT and should be considered as an important confounding factor in future researches.

The aim of the present study was to investigate the potential improvement in detection rate of nodal and distant metastasis and the resultant impact on clinical management by PET-based diagnostic work up in comparison with conventional imaging modalities in various clinical settings in patients with breast cancer.
Of a total 256 patients with breast cancer who were referred to PET/CT division, MasihDaneshvari Hospital between May 2013 and Mar. 2016, 123 cases were included. Definitely-positive PET/CT findings in primary site as well as N1 (level I, II ipsilateral axillary nodes), N2 (ipsilateral internal mammary), N3 (ipsilateral internal mammary level I, II ipsilateral axillary, ipsilateral level II axillary, ipsilateral supraclavicular node) and distant metastasis (distant node and viscera) and related impact on clinical management (upstaging or downstaging) were retrospectively identified from the report archive and then compared with the results of baseline imaging modalities including CT scan, sonography, bone scan, C-X ray, MRI, MRM and mammography obtained from patient medical records. The most typical imaging pattern was considered as the reference standard. Indeterminant and equivocal PET positive lesion were not included in the study.
Fourteen (11.38%) and 109 (88.62%) out of 123 patients were referred for staging and restaging/recurrence/surveillance, respectively. Mean age were 51.42 (34 - 62) and 52.66 (29 - 79) for staging and restaging groups, respectively. In staging group, 18 F FDG PET/CT recognized definitely positive additional nodal involvement in 21.4% of patients all of them related to the supraclavicular level and hence result in change N staging to N3. Additional metastatic lesions on a per lesion-basis and a per organ-basis were identified as 28.6% and 14.3%, repsectively. A significant change in patient management occurred in 42.9% (35.7% upstaging, 7.2% down staging). In restaging group, locoregional detection rate in biopsy proved recurrence was 100%. Additional nodal detection and the resultant change in N staging were 29.6% and 28.7%, respectively. Supraclavicular node detection contribute in 53.12% of overall change in N staging followed by axillary node and internal mammary equally (15.62%). Additional metastatic lesions on a per lesion-basis and per organ-basis were identified in 53.2% and 44%, respectively. Ultimate change in patients’ management was found in 42.9%.
18 F FDG PET/CT is a valuable imaging tool in initial and subsequent treatment strategy in patients with breast cancer by providing additional nodal and distant metastasis and may have the promising future potential to be as the imaging modality of choice for accurate assessment of disease extension in breast cancer in routine clinical practice.

Observations on Tuberculosis HIV co-infection in addition to epidemiologic molecular studies have recently provided strong evidence for the state of immune system as the major determinant of the TB imaging spectrum. However, the presence of any correlation between radiographic findings and the degree of suppression in HIV positive patients still remains controversial. The present study aimed to investigate the TB radiographic manifestation in HIV positive patients and its relationship to the CD4 positive cell count.
Chest radiography of 15 HIV positive patients with a definite diagnosis of pulmonary Tuberculosis in Masih Daneshvari hospital, between 2013 - 2014, were retrospectively reviewed. Radiographic findings and severity were categorized as typical (upper lobe infiltration/cavity) and atypical (middle/lower lobe opacity, adenopathy, pleural effusion and normal X-ray). Demographics and CD4 positive cell count were also recorded. Data analysis was performed using SPSS version 23 (frequency and mean for descriptive quantitative variables and Logistic regression analysis for correlation, P Of a total 15 patients (86.7% men and 13.3% women), 78.6% had CD4 positive counts below 350 (mean ± SD; 229.15 ± 199.45). The most common radiographic findings in descending order of frequency were adenopathy (53.3%), pleural effusion (26.7%) and cavitation (6.7%) with an overall atypical presentation of 93.3%. This study failed to reveal any statistically significant correlation between CD4 positive cell count and radiographic manifestation as well as severity.
In CD4 positive cell count below 500, the dominant radiographic pattern of Tuberculosis is atypical presentation. At this level of immunity, CD 4 positive T cell dysfunction may play a deterministic role in TB radiographic manifestation.

Synovial sarcoma is an uncommon soft tissue tumor occurring mainly in the periarticular region of the extremities in young adults. It happens less frequently in the head and neck, mediastinum, lungs, heart, and digestive tract. A 28-year-old man two months after total esophagectomy with final diagnosis of esophageal synovial sarcoma was referred to our Positron Emission Tomography (PET-CT) department for the evaluation of treatment response and further treatment planning. To our knowledge this case is the 11th case of esophageal synovial sarcoma, being reported in the literature. We presented the 11th case of esophageal synovial sarcoma. Synovial sarcomas are very rare tumor entities, particularly in the gastrointestinal tract and are likely to be mistaken with other more common tumors such as gastrointestinal stromal tumors.