Whole-body 18F-fluorodeoxyglucose Research Articles

Application of 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in recurrent anastomotic tumors after surgery in digestive tract tumors.

This study was to investigate the application value of whole-body dynamic 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging in recurrent anastomotic tumors of digestive tract after gastric and esophageal cancer surgery. Postoperative patients with gastric and esophageal cancer have a high risk of tumor recurrence, and traditional imaging methods have certain limitations in early detection of recurrent tumors. Whole-body dynamic 18F-FDG PET/CT imaging, due to its high sensitivity and specificity, can provide comprehensive information on tumor metabolic activity, which is expected to improve the early diagnosis rate of postoperative recurrent tumors, and provide an important reference for clinical treatment decision-making. To investigate the clinical value of whole-body dynamic 18F-FDG PET/CT imaging in differentiating anastomotic recurrence and inflammation after the operation of upper digestive tract tumors. A retrospective analysis was performed on 53 patients with upper digestive tract tumors after operation and systemic dynamic 18F-FDG PET/CT imaging indicating abnormal FDG uptake by anastomosis, including 29 cases of gastric cancer and 24 cases of esophageal cancer. According to the follow-up results of gastroscopy and other imaging examinations before and after PET/CT examination, the patients were divided into an anastomotic recurrence group and anastomotic inflammation group. Patlak multi-parameter analysis software was used to obtain the metabolic rate (MRFDG), volume of distribution maximum (DVmax) of anastomotic lesions, and MRmean and DVmean of normal liver tissue. The lesion/background ratio (LBR) was calculated by dividing the MRFDG and DVmax of the anastomotic lesion by the MRmean and DVmean of the normal liver tissue, respectively, to obtain LBR-MRFDG and LBR-DVmax. An independent sample t test was used for statistical analysis, and a receiver operating characteristic curve was used to analyze the differential diagnostic efficacy of each parameter for anastomotic recurrence and inflammation. The dynamic 18F-FDG PET/CT imaging parameters MRFDG, DVmax, LBR-MRFDG, and LBR-DVmax of postoperative anastomotic lesions in gastric cancer and esophageal cancer showed statistically significant differences between the recurrence group and the inflammatory group (P < 0.05). The parameter LBR-MRFDG showed good diagnostic efficacy in differentiating anastomotic inflammation from recurrent lesions. In the gastric cancer group, the area under the curve (AUC) value was 0.935 (0.778, 0.993) when the threshold was 1.83, and in the esophageal cancer group, the AUC value was 1. When 86 is the threshold, the AUC value is 0.927 (0.743, 0.993). Whole-body dynamic 18F-FDG PET/CT imaging can accurately differentiate the diagnosis of postoperative anastomotic recurrence and inflammation of gastric cancer and esophageal cancer and has the potential to be an effective monitoring method for patients with upper digestive tract tumors after surgical treatment.

Multi-level tuberculosis of the spine identified by 18F-FDG-PET/CT and concomitant urogenital tuberculosis: a case report from the spinal TB X cohort.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis (Mtb) and typically infects the lungs. However, extrapulmonary forms of TB can be found in approximately 20% of cases. It is suggested, that up to 10% of extrapulmonary TB affects the musculoskeletal system, in which spinal elements (spinal tuberculosis, STB) are involved in approximately 50% of the cases. STB is a debilitating disease with nonspecific symptoms and diagnosis is often delayed for months to years. In our Spinal TB X Cohort, we aim to describe the clinical phenotype of STB using whole-body 18F-fluorodeoxyglucose positron emission tomography computed tomography (PET/CT) and to identify a specific gene expression profile for the different stages of dissemination on PET/CT. Here we report on the first patient recruited into our cohort who underwent PET/CT before treatment initiation, at 6-months and at 12-months - time of TB treatment completion. A 27-year-old immunocompetent male presented with severe thoracolumbar back pain for 9 months with severe antalgic gait and night sweats. Magnetic resonance imaging (MRI) of the whole spine revealed multilevel spinal disease (T5/6, T11/12, L3/4) in keeping with STB. After informed consent and recruitment into the Spinal TB X Cohort, the patient underwent PET/CT as per protocol, which revealed isolated multilevel STB (T4-7, T11/12, L3/4) with no concomitant lung or urogenital lesion. However, sputum and urine were Xpert MTB/RIF Ultra positive and Mtb was cultured from the urine sample. CT-guided biopsy of the T11/12 lesion confirmed drug-sensitive Mtb on Xpert MTB/RIF Ultra and the patient was started on TB treatment according to local guidelines for 12 months. The 6-month follow-up PET/CT revealed new and existing spinal lesions with increased FDG-uptake despite significant improvement of clinical features and laboratory markers. After 9 months of treatment, the patient developed an acute urethral stricture, most likely due to urogenital TB, and a suprapubic catheter was inserted. The 12-month PET/CT showed significantly decreased PET/CT values of all lesions, however, significant persistent spinal inflammation was present at the end of TB treatment. Clinically, the patient was considered cured by the TB control program and currently awaits urethroplasty. In our case, PET/CT emerged as a valuable imaging modality for the initial assessment, surpassing MRI by revealing more comprehensive extensive disease. Subsequent PET/CT scans at 6-month uncovered new lesions and increased inflammation in existing ones, while by the end of TB treatment, all lesions exhibited improvement. However, the interpretation of FDG avidity remains ambiguous, whether it correlates with active infection and viable Mtb. or fibro- and osteoblast activity indicative of the healing process. Additionally, the absence of extraspinal TB lesions on PET/CT despite positive microbiology from sputum and urine maybe explained by paucibacillary, subclinical infection of extraspinal organs. The Spinal TB X Cohort endeavours to shed light on whole-body imaging patterns at diagnosis, their evolution midway through TB treatment, and upon treatment completion. Ultimately, this study aims to advance our understanding of the biology of this complex disease.

Reduced count pediatric whole-body 18F-FDG PET imaging reconstruction with a Bayesian penalized likelihood algorithm.

Advanced positron emission tomography (PET) image reconstruction methods promise to allow optimized PET/CT protocols with improved image quality,decreased administered activity and/or acquisition times. To evaluate the impact of reducing counts(simulating reduced acquisition time) in block sequential regularized expectation maximization (BSREM) reconstructed pediatric whole-body 18F-fluorodeoxyglucose (FDG) PET images, and to compare BSERM with ordered-subset expectation maximization (OSEM) reconstructed reduced-count images. Twenty children (16 male) underwent clinical whole-body 18F-FDG PET/CT examinations using a 25-cm axial field-of-view (FOV) digital PET/CT system at 90s per bed (s/bed) with BSREM reconstruction (β=700). Reduced count simulations with varied BSREM β levels were generated from list-mode data: 60s/bed, β=800; 50s/bed, β=900; 40s/bed, β=1000; and 30s/bed, β=1300. In addition, a single OSEM reconstruction was created at 60s/bed based on prior literature. Qualitative (Likert scores) and quantitative (standardized uptake value [SUV]) analyses were performed to evaluate image quality and quantitation across simulated reconstructions. The mean patient age was 9.0 ± 5.5 (SD) years, mean weight was 38.5 ± 24.5kg, and mean administered 18F-FDG activity was 4.5 ± 0.7 (SD) MBq/kg. Between BSREM reconstructions, no qualitative measure showed a significant difference versus the 90s/bed β=700 standard (all P>0.05). SUVmax values for lesions were significantly lower from 90s/bed, β=700 only at a simulated acquisition time of 30s/bed, β=1300 (P=0.001). In a side-by-side comparison of BSREM versus OSEM reconstructions, 40s/bed, β=1000 images were generally preferred over 60s/bed TOF OSEM images. In children who undergo whole-body 18F-FDG PET/CT on a 25-cm FOV digital PET/CT scanner, reductions in acquisition time or, by corollary, administered radiopharmaceutical activity of >50% from a clinical standard of 90s/bed may be possible while maintaining diagnostic quality when a BSREM reconstruction algorithm is used.

Metabolic interactions between organs in overweight and obesity using total-body positron emission tomography.

Overweight and obesity is a complex condition resulting from unbalanced energy homeostasis among various organs. However, systemic abnormalities in overweight and obese people are seldom explored in vivo by metabolic imaging techniques. The aim of this study was to determine metabolic abnormities throughout the body in overweight and obese adults using total-body positron emission tomography (PET) glucose uptake imaging. Thirty normal weight subjects [body mass index (BMI) < 25 kg/m2, 55.47 ± 13.94 years, 16 men and 14 women], and 26 overweight and obese subjects [BMI ≥ 25 kg/m2, 52.38 ± 9.52 years, 21 men and 5 women] received whole-body 18F-fluorodeoxyglucose PET imaging using the uEXPLORER. Whole-body standardized uptake value normalized by lean body mass (SUL) images were calculated. Metabolic networks were constructed based on the whole-body SUL images using covariance network approach. Both group-level and individual-level network differences between normal weight and overweight/obese subjects were evaluated. Correlation analysis was conducted between network properties and BMI for the overweight/obese subjects. Compared with normal weight subjects, overweight/obese subjects exhibited altered network connectivity strength in four network nodes, namely the pancreas (p = 0.033), spleen (p = 0.021), visceral adipose tissue (VAT) (p = 1.12 × 10-5) and bone (p = 0.021). Network deviations of overweight/obese subjects from the normal weight were positively correlated with BMI (r = 0.718, p = 3.64 × 10-5). In addition, overweight/obese subjects experienced altered connections between organs, and some of the altered connections, including pancreas-right lung and VAT-bilateral lung connections were significantly correlated with BMI. Overweight/obese individuals exhibit metabolic alterations in organ level, and altered metabolic interactions at the systemic level. The proposed approach using total-body PET imaging can reveal individual metabolic variability and metabolic deviations between organs, which would open up a new path for understanding metabolic alterations in overweight and obesity.

Multimodality Appearances of Marginal Zone Lymphoma Masquerading as Cryptogenic Organizing Pneumonia-serial Chest Radiograph and High-resolution Computed Tomography Appearances: (18F) Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Staging Utility.

Marginal zone lymphoma (MZL) is a group of low-grade, indolent, non-Hodgkin lymphomas rarely manifesting in the lungs. A 46-year-old man presenting with shortness of breath and cough was investigated and treated over 10 months for an atypical pattern of lung disease in keeping with cryptogenic organizing pneumonia (COP). Initial lung biopsies were nondiagnostic - repeat sampling eventually showed MZL. Staging whole-body (18F) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) demonstrated multisystem stage IV disease with intensely avid widespread pulmonary changes resembling COP. The case elegantly illustrates that pulmonary MZL can present insidiously masquerading as COP and shows the value of (18F) FDG PET/CT to stage extranodal MZL.

The accuracy of whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the detection of ovarian cancer relapse in patients with rising cancer antigen 125 (CA-125) levels

Background18F-fluorodeoxyglucose (FDG) PET/CT is a noninvasive imaging tool that has been used successfully for the diagnosis, staging, restaging, therapy monitoring, and prognostic prediction of ovarian cancer. For ovarian cancer surveillance, rising CA-125 levels raise the suspicion of recurrence despite its reported low specificity; being elevated in other benign and inflammatory conditions, and thus, confirmation is required. This work aimed to evaluate the role of 18F-FDG PET/CT in suspected ovarian cancer recurrence in patients presenting with elevated CA-125 levels.ResultsFifty female patients with suspected ovarian cancer recurrence owing to elevated CA-125 levels were included in this study. Recurrence was confirmed in 46/50 cases whether by histopathological confirmation or by serial follow-up imaging and clinical follow-up. Positive PET/CT findings were reported in 45/50 cases with 2 false-negative cases and 1 false-positive case. PET/CT examination was found to be superior to contrast-enhanced CT in the detection of peritoneal metastatic nodules and metastatic lymph nodes. According to this study, the estimated sensitivity, specificity, and overall diagnostic accuracy of PET/CT in the detection of recurrent ovarian cancer were 95.6%, 75%, and 94%, respectively.ConclusionsIn ovarian cancer surveillance, 18F-FDG PET/CT was found to be a sensitive and accurate noninvasive imaging tool that can be used in the detection of recurrent ovarian cancer in patients with elevated CA-125 levels, thus interfering with the management plan. The advantage of whole-body imaging in PET/CT allows for the detection and precise localization of recurrent or metastatic foci in abdominal and extra-abdominal sites as well.

Cardiac Insulin Resistance in Subjects With Metabolic Syndrome Traits and Early Subclinical Atherosclerosis.

Experimental evidence suggests that metabolic syndrome (MetS) is associated with changes in cardiac metabolism. Whether this association occurs in humans is unknown. 821 asymptomatic individuals from the Progression of Early Subclinical Atherosclerosis (PESA) study (50.6 [46.9-53.6] years, 83.7% male) underwent two whole-body 18F-fluorodeoxyglucose positron emission tomography-magnetic resonance (18F-FDG PET-MR) 4.8 ± 0.6 years apart. Presence of myocardial 18F-FDG uptake was evaluated qualitatively and quantitatively. No myocardial uptake was grade 0, while positive uptake was classified in grades 1-3 according to target-to-background ratio tertiles. One hundred fifty-six participants (19.0%) showed no myocardial 18F-FDG uptake, and this was significantly associated with higher prevalence of MetS (29.0% vs. 13.9%, P < 0.001), hypertension (29.0% vs. 18.0%, P = 0.002), and diabetes (11.0% vs. 3.2%, P < 0.001), and with higher insulin resistance index (HOMA-IR, 1.64% vs. 1.23%, P < 0.001). Absence of myocardial uptake was associated with higher prevalence of early atherosclerosis (i.e., arterial 18F-FDG uptake, P = 0.004). On follow-up, the associations between myocardial 18F-FDG uptake and risk factors were replicated, and MetS was more frequent in the group without myocardial uptake. The increase in HOMA-IR was associated with a progressive decrease in myocardial uptake (P < 0.001). In 82% of subjects, the categorization according to presence/absence of myocardial 18F-FDG uptake did not change between baseline and follow-up. MetS regression on follow-up was associated with a significant (P < 0.001) increase in myocardial uptake. Apparently healthy individuals without cardiac 18F-FDG uptake have higher HOMA-IR and higher prevalence of MetS traits, cardiovascular risk factors, and early atherosclerosis. An improvement in cardiometabolic profile is associated with the recovery of myocardial 18F-FDG uptake at follow-up.

Prognostic value of whole-body dynamic 18F-FDG PET/CT Patlak in diffuse large B-cell lymphoma

ObjectiveThis study aims to investigate the significance of interim whole-body dynamic 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) Patlak parameters for predicting the prognosis of patients with diffuse large B-cell lymphoma. To estimate the predictive value of the whole-body dynamic 18F-FDG PET/CT Patlak parameter for 2-year progression-free survival (PFS) and 2-year overall survival (OS). MethodsThis study reports the findings of 67 patients with diffuse large B-cell lymphoma (DLBCL). These patients underwent interim whole-body dynamic 18F-FDG PET/CT scans from June 2021 to January 2023 at the Department of Nuclear Medicine, First Affiliated Hospital of Anhui Medical University. The predictive values of maximum standard uptake value (SUVmax), maximum of net glucose uptake rate (Kimax) and the predictive model combining Kimax and interim treatment response on the prognosis of patients was analyzed using receiver operating characteristic (ROC) curves. Kaplan-Meier survival curves and log-rank tests were used for survival analysis. Univariate and multivariate analyses were performed to screen for independent prognostic risk factors. ResultsAfter a median follow-up of 18 months, 21 patients (31.3%) experienced disease recurrence or death. The cut-off values for the SUVmax and the Kimax were 6.1 and 0.13 μmol min−1·ml−1, respectively. Ann Arbor stage, IPI, SUVmax, Kimax and interim treatment response were associated with PFS and OS in the univariate analysis. However, only Kimax and interim treatment response were independent influences on PFS and OS in multivariate analysis. ConclusionInterim whole-body dynamic 18F-FDG PET/CT Patlak imaging has significant prognostic value in patients with DLBCL. Among them, the interim dynamic parameter Kimax showed the best predictive value for prognosis compared with the interim SUVmax and interim treatment response. The predictive model established by Kimax and the interim treatment response allowed for the accurate stratification of the prognostic risk of DLBCL.

Conventional Imaging, MRI and 18F-FDG PET/MRI for N and M Staging in Patients with Newly Diagnosed Breast Cancer.

Background: This study compares the diagnostic potential of conventional staging (computed tomography (CT), axillary sonography and bone scintigraphy), whole-body magnetic resonance imaging (MRI) and whole-body 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/)MRI for N and M staging in newly diagnosed breast cancer. Methods: A total of 208 patients with newly diagnosed breast cancer were prospectively included in this study and underwent contrast-enhanced thoracoabdominal CT, bone scintigraphy and axillary sonography as well as contrast-enhanced whole-body 18F-FDG PET/MRI. The datasets were analyzed with respect to lesion localization and characterization. Histopathology and follow-up imaging served as the reference standard. A McNemar test was used to compare the diagnostic performance of conventional staging, MRI and 18F-FDG PET/MRI and a Wilcoxon test was used to compare differences in true positive findings for nodal staging. Results: Conventional staging determined the N stage with a sensitivity of 80.9%, a specificity of 99.2%, a PPV (positive predictive value) of 98.6% and a NPV (negative predictive value) of 87.4%. The corresponding results for MRI were 79.6%, 100%, 100% and 87.0%, and were 86.5%, 94.1%, 91.7% and 90.3% for 18F-FDG PET/MRI. 18F-FDG PET/MRI was significantly more sensitive in determining malignant lymph nodes than conventional imaging and MRI (p < 0.0001 and p = 0.0005). Furthermore, 18F-FDG PET/MRI accurately estimated the clinical lymph node stage in significantly more cases than conventional imaging and MRI (each p < 0.05). Sensitivity, specificity, PPV and NPV for the M stage in conventional staging were 83.3%, 98.5%, 76.9% and 98.9%, respectively. The corresponding results for both MRI and 18F-FDG PET/MRI were 100.0%, 98.5%, 80.0% and 100.0%. No significant differences between the imaging modalities were seen for the staging of distant metastases. Conclusions:18F-FDG PET/MRI detects lymph node metastases in significantly more patients and estimates clinical lymph node stage more accurately than conventional imaging and MRI. No significant differences were found between imaging modalities with respect to the detection of distant metastases.

Whole-body 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Demonstrating Multiple Rare Extracranial Metastases in a Treated Case of Glioblastoma.

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults that accounts for nearly 20% of all primary malignant brain tumors. While GBM is notable for local recurrence and invasion, extracranial metastases (ECMs) are exceedingly rare, occurring in <2% of patients. However, the report of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging in evaluating ECM is limited, and the importance of whole-body FDG PET/CT imaging in GBM has not been well elucidated. We present here a case of GBM, post excision 12 years before, whole-body 18F-FDG PET/CT showing no recurrence in the brain and ECM to multiple bones, right kidney, and pancreas.

Extranodal involvement of posttransplant lymphoproliferative disorder detected on 18F‐fluorodeoxyglucose‐positron emission tomography/computed tomography

A 69-year-old man with a history of kidney transplantation presented with ring-enhancing lesions in the left frontal lobe, thalamus, and right insula (Figure 1a) on magnetic resonance imaging. He was hospitalized with a diagnosis of cytomegalovirus encephalitis and had taken anti-inflammatory therapy. Follow up imaging showed a decrease in lesion size in the left frontal lobe and thalamus; however, the right insular lesion increased in size and new ones were identified in the corpus callosum and periventricular white matter (Figure 1a). The tumor markers CA125, CYFRA21-1, CEA, PSA, and fPSA were all positive on blood testing. Because anti-inflammatory therapy was ineffective and malignant tumor could not be excluded on imaging alone, whole-body 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) was performed (Figure 1b). Body imaging showed multiple hypermetabolic nodular lesions in the thoracic and abdominal superficial soft tissue (maximum standardized uptake value, 13.06), which suggested malignancy. Head imaging showed decreased activity in the brain lesions. A diagnosis of lymphoma was suspected. Punch biopsy of a superficial soft tissue nodule was consistent with B cell-derived posttransplant lymphoproliferative disorder (PTLD) (Figure 1c,d). Brain MRI, 18F-FDG PET, and histopathological findings in a 69-year-old male patient with posttransplant lymphoproliferative disorder. (a) Abnormal signals in T2-flair MRI images within 3 months (solid arrow). (b) 18F-FDG PET/CT images show multiple lesions in superficial soft tissue nodules with hypermetabolism and decreased FDG activity of intracranial lesions (solid arrow). (c) Immunohistochemical staining shows positive CD3. (d) Immunohistochemical staining shows enlarged B cells (solid arrow). 18F-FDG, 18F-fluorodeoxyglucose; CT, computed tomography; PET, positron emission tomography. PTLD is a rare group of heterogeneous lymphoproliferative conditions that occur after solid organ or hematopoietic transplantation [1, 2]. With allograft transplantation, the anatomic site of PTLD involvement usually depends on the type of transplant [3]. Reported incidence rates of involvement of the central nervous system range between 10% and 15% [4, 5]. However, simultaneous involvement of the central nervous system [6] and superficial soft tissue [7] are rare. To date, only two cases of PTLD soft tissue nodules have been reported [4]. Characteristics of PTLD on magnetic resonance imaging are not specific; however, PTLD can be detected on 18F-FDG-PET with an overall sensitivity and specificity of approximately 90% [8, 9]. PTLD should be considered when multiple hypermetabolic superficial soft tissue nodules and central nervous system lesions are encountered in transplantation patients. Whole-body18F-FDG-PET/CT is more effective than single-site imaging for diagnosing or staging PTLD. Bojun Wang: Data curation (lead); Writing – original draft (lead). Tianbin Song: Conceptualization (equal); Writing – review & editing (equal). Chun Zhang: Conceptualization (equal); Supervision (equal). Jie Lu: Supervision (equal). Zhigang Liang: Supervision (equal); Writing – review & editing (equal). We thank Dr. Lianghong Teng (Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China) who provided support of pathological picture of this case. All the authors declare that they have no conflict or potential conflict of interest. This article does not contain any studies with animals performed by any of the authors. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Informed consent was obtained from the patient and his parents for the anonymous use of his clinical, imaging, and histologic data for publication. The data that support the findings of this study are available from the corresponding author, upon reasonable request.

A Rare Case of Thyroid Cartilage Metastases Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

The thyroid cartilage metastatic involvement is an extremely rare entity. It can be asymptomatic at the earlier stage and can become symptomatic later on. Involvement of thyroid cartilage is frequent in melanoma and renal and rarely reported in an advanced stage of carcinoma prostate, breast, and lung. These cases were usually reported on positron emission tomography/computed tomography (PET/CT) as can often easily be missed on computed tomography scan alone. We present a case report of metastatic involvement of thyroid cartilage in squamous cell carcinoma of buccal mucosa detected on the whole-body 18F-fluorodeoxyglucose PET/CT.

Modified signal-to-noise ratio in the liver using the background-to-lung activity ratio to assess image quality of whole-body 18F-fluorodeoxyglucose positron emission tomography.

The signal-to-noise ratio in the liver (SNR liver) is commonly used to assess the quality of positron emission tomography (PET) images; however, it is weakly correlated with visual assessments. Conversely, the noise equivalent count (NEC) density showed a strong correlation with visual assessment but did not consider the effects of image reconstruction conditions. Therefore, we propose a new indicator, the modified SNR liver, and plan to verify its usefulness by comparing it with conventional indicators. We retrospectively analyzed 103 patients who underwent whole-body PET/computed tomography (CT). Approximately 60min after the intravenous injection of 18F-fluorodeoxyglucose (FDG), the participants were scanned for 2min/bed. The SNR liver and NEC density were calculated according to the Japanese guidelines for oncology FDG-PET/CT. The modified SNR live was calculated by multiplying the background-to-lung activity ratio by the SNR liver. Patients were classified into groups based on body mass index (BMI) and visual scores. Subsequently, the relationships between these physical indicators, BMI, and visual scores were evaluated. Although the relationship between the modified SNR liver and BMI was inferior to that of NEC density and BMI, the modified SNR liver distinguished the BMI groups more clearly than the conventional SNR liver. Additionally, the modified SNR liver distinguished low visual scores from high scores more accurately than the conventional SNR liver and NEC density. Whether the modified SNR liver is more suitable than the NEC density remains equivocal; however, the modified SNR liver may be superior to the conventional SNR liver for image-quality assessment.

Is It Possible to Omit Bone Marrow Biopsy in Diagnostic Workup in Patients with Newly Diagnosed Primary CNS Lymphoma? a Retrospective Analysis in the PET/CT Era

Background: Primary central nervous system lymphoma (PCNSL) is a rare and aggressive extra-nodal non-Hodgkin lymphoma (NHL) confined to the brain, eyes, leptomeninges, and spinal cord. More than 90% of patients belong to diffuse large B-cell lymphoma (DLBCL). The consensus around the extensive systematic staging in patients with suspected or proven PCNSL is still a matter of debate. Current diagnostic and staging guidelines recommend extensive workup to exclude systemic disease with computed tomography (CT) scan of the chest, abdomen, and pelvis, a bone marrow biopsy (BMB), and testicular ultrasonography in males. Whole-body 18F-fluorodeoxyglucose positron emission tomography (PET-CT) is currently considered optional in diagnostic workup in patients with presumed PCNSL. The utility of BMB in the era of PET-CT has been challenged in systemic lymphomas, but data are lacking for patients with PCNSL. Among patients with PCNSL, BMB is often normal or reveals low-grade lymphomas or just clonal B-cells. In rare instances, aggressive lymphoma involves both bone marrow (BM) and the central nervous system (CNS). However, the role of BMB in PCNSL patients in the PET-CT era is yet to be established. This study aimed to analyze whether BMB could be safely omitted in the diagnostic workup in patients with PCNSL of DLBCL histology without signs of systemic lymphoma on PET-CT scans. Methods: A comprehensive nationwide retrospective multicenter study with enrollment of patients from the referent medical centers in Denmark for treatment of PCNSL was performed. Patients included in the study were diagnosed between 2002 and 2020 and identified through the Danish Pathology Register. All patients with CNS involvement were potential candidates. Inclusion criteria were the following: 1) patients should be diagnosed with DLBCL in brain, eyes, leptomeninges, cerebrospinal fluid, and spinal cord; 2) have available BMB; and 3) have available PET-CT without signs of lymphoma outside of CNS. Patients with PCNSL and prior history of other lymphoma were also included in the study. Patients were excluded if they were diagnosed with systemic lymphoma or PCNSL other than DLBCL. Patients who did not have PET-CT and BMB performed or in whom this information could not be retrieved through medical records were also excluded from further analysis. Results: Of 1238 potential candidates identified through the Danish pathology register, only 300 patients fulfilled the inclusion criteria. Most patients were excluded due to a lack of information on PET-CT scans and BMB. All included patients had available BMB and no signs of systemic lymphoma on PET-CT. Of the included patients, 252 (84%) were diagnosed with PCNSL without a previous lymphoma diagnosis, while 48 (16%) had a previous history of lymphoma. The median age of patients was 68 years. There was a slight predomination of men (60%) compared to women (40%). Twenty-three (7.7%) patients were found to have discordant findings in BMB. However, none of these showed infiltration with DLBCL. The histologies included various low-grade lymphomas found in 17 patients (5.7%), monoclonal B-cells in 3 patients (1%), and smoldering multiple myeloma in one patient. Conclusion: In this retrospective study of 300 patients with PCNSL with PET-CT scans without signs of systemic lymphoma outside CNS, we found no cases with BM infiltration of DLBCL. A small proportion of patients with PCNSL have a discordant, often low-grade lymphoma in the bone marrow. With a sample size of 300, the chance of overlooking DLBCL infiltration in the BM is ≤ 1 % (95% CI). Therefore, the results of this, so far the most extensive study evaluating BMB in PCNSL in the PET-CT era, suggest that BMB can safely be omitted in patients with PCNSL of DLBCL histology and no signs of systemic lymphoma on PET-CT scans.

Frequency of skeletal metastasis on 18F-fluorodeoxyglucose positron emission tomography/computed tomography with negative computed tomography at Institute of Nuclear Medicine and Oncology

Background: Skeletal metastasis (SM) with skeletal related events (SREs) occurs in up to 70% of breast cancer and more than 50% of malignant tumors. Whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) used to characterize the metabolic, anatomic, and morphologic status of suspected bone lesions. SMs are detected using multiple modalities; however, FDG PET/CT may offer a single investigation to detect SM combining the strength of functional imaging and radiological imaging simultaneously. Aims and Objectives: This study was to assess the frequency of SM on 18F-FDG PET/CT with negative CT at Institute of Nuclear Medicine and Oncology (INMOL). Materials and Methods: This cross-sectional study included a sample of total 50 patients with SM of known primary malignancies who underwent 18F-FDG PET/CT scan at INMOL Cancer Hospital, Lahore. Results: Of the 50 patients, we discovered the concordant findings between PET and CT as both PET+/CT+ in 38 patients (76%) whereas in 12 patients (24%) with PET+/CT- findings were discordant. CT was unable to detect SM in at least 12 patients. The maximum standardized uptake value (SUVmax) of SM in patients with negative CT found to be slightly higher as 5.2±4.1 (range: 2.5–7.8) than in patients with positive CT finding as 4.8±2.8 (range: 3.9–5.8) with P=0.76. P-value is insignificant this means that high SUV is not typical or conclusive evidence of metastasis. Conclusion: Despite limited data, this study has demonstrated high concordance between FDG PET and CT scan in detecting SM. Furthermore, the study has shown that 18F-FDG PET appears to have slightly better detection efficiency as compared to CT for identification of SM which is statistically insignificant. The study demonstrated that SUV is higher in PET and CT discordant cases; however, it does not provide conclusive information favoring diagnosis of SM.

Respiratory-gated 18F Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Imaging in Evaluation of Primary Gastric Lesions and Gastric Lymph Nodes in Patients with Gastric Cancer

AimsTo evaluate the added value of respiratory-gated positron emission tomography (PET) in 18F fluorodeoxyglucose (FDG) PET/magnetic resonance imaging (MRI) in the visual and semi-quantitative assessment of primary gastric lesions and gastric lymph nodes for patients with gastric cancer. Materials and methodsIn total, 102 upper abdominal respiratory-gated and whole-body 18F FDG PET/MRI of 88 patients with gastric cancer were evaluated visually and semi-quantitatively. For 41 patients who underwent surgery, histopathological and PET findings were compared. Three PET images were obtained from upper abdominal PET data: non-Q static (non-QS) PET from all counts, respiratory-gated Q static (QS) PET from counts in the end-expiration phase of breathing, shortened 4 min (S4min) PET that was reconstructed to obtain similar counts to QS PET. The semi-quantitative parameters (standardised uptake values, metabolic tumour volume, total lesion glycolysis) of primary lesions for each PET image, the sizes of primary lesions and the patient's body mass index were recorded. According to lymph node stations, the presence and numbers of positive lymph nodes and visual scores of lymph nodes for each PET image were recorded. ResultsThe patients with smaller gastric lesions (≤30 mm) or higher body mass index (>30) had significantly higher standardised uptake value percentage changes in QS PET compared with non-QS PET (all P < 0.05). The third (lesser curvature), fourth (greater curvature) and sixth (infra-pyloric) lymph node stations had significantly higher visual scores in the QS PET than in the others. The fourth lymph node station had a significantly higher number of FDG-positive lymph node in the QS PET than in the non-QS and the whole-body PET images. In the fourth station, sensitivity, positive predictive value, negative predictive value and accuracy increased in the QS PET compared with the others. ConclusionRespiratory-gated PET/MRI was found to be significantly superior in the evaluation of especially the fourth lymph node station, smaller gastric lesions and in the patients with a higher BMI compared with the non-respiratory-gated PET images.

Central nervous system mature teratoma producing carbohydrate antigen 19-9: illustrative case.

Central nervous system (CNS) mature teratoma is a rare disease with symptoms that can vary according to tumor location. Most lesions are benign; rarely, malignancy can develop in any of the somatic components. Elevated levels of tumor markers such as α-fetoprotein and β-human chorionic gonadotropin are not usually found in patients with CNS mature teratoma, and no reports have described an association with carbohydrate antigen 19-9 (CA19-9). A 64-year-old woman with headache was found to have a mass lesion in the anterior cranial fossa. Magnetic resonance imaging of the brain suggested a mature teratoma. Serum and cerebrospinal fluid (CSF) tests showed significant CA19-9 elevations (2,770 U/mL and 4,387 U/mL, respectively). Other examinations, including whole-body 18F-fluorodeoxyglucose positron emission tomography, did not detect the origin of elevated CA19-9, suggesting that the high CA19-9 levels were caused by intracranial tumor. The patient underwent tumor removal. The histopathological diagnosis was mature teratoma with positive CA19-9 staining. CA19-9 levels in serum and CSF decreased significantly after tumor removal. The histopathological findings and postoperative decreased CA19-9 levels established the diagnosis of CA19-9-producing CNS mature teratoma. CNS mature teratoma can cause elevations in CA19-9 in cases with absence of neoplasms in the trunk.

The value of FDG PET/CT in the management of malignant melanoma: a retrospective study

Objectives: Positron Emission Tomography with Computed Tomography (PET/CT) is a valuable imaging method for the restaging of malignant diseases as well as the evaluation of treatment outcomes. Malignant melanoma is an aggressive tumor. Surgical resection is the primary treatment. As melanoma lesions are mostly FDG-avid, whole-body 18F-fluorodeoxyglucose (18F-FDG) PET/CT imaging modality can be used to determine the spread of the tumor. In the present study, we intended to share our clinical experience with FDG PET/CT in malignant melanoma patients under different kinds of treatment. Methods: In this retrospective study, the data sets of 122 patients who had surgical resection of known primary tumors, all of which were histopathology-proven malignant melanoma, were analyzed. All patients underwent baseline 18F-FDG PET/CT scan no sooner than 45 days and at least once after surgery. Clinical information, radiological imaging, histopathology, and treatment modalities were noted for all patients, and 18F-FDG PET/CT findings were examined. Results: All patients were histopathology-proven and 47 of them had acral lentiginous, 37 nodular, 23 amelanotic, and 15 atypical malignant melanoma. Local recurrence was detected by 18F-FDG PET/CT in 13 (10.6%; 3 male, 10 female) of the 122 patients, and the mean recurrence time after diagnosis was 3 ± 1.4 years. 10 patients with brain and bone metastases underwent radiotherapy. 19 patients with lung, bone, and hepatic metastases received chemotherapy and 22 patients immunotherapy. Conclusions: Malignant melanoma is a type of skin cancer that may involve any organ. In localized cases, complete surgical resection may be adequate for a cure. If diagnosed with the latter type, the whole body of the patient must be examined.

MAGIC OF ADVANCED IMAGING AND IMMUNOTHERAPY IN CARDIAC SARCOIDOSIS

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: This case report emphasizes the role of advanced imaging and immunotherapy in the diagnosis and management of cardiac sarcoidosis (CS). CASE PRESENTATION: A 52-year-old healthy male presented with near-syncope for 5 days. He had a blood pressure of 164/67 mmHg and a heart rate of 43 bpm. Electrocardiogram revealed complete-heart-block (CHB) with a ventricular rate of 38/min. Troponin T and electrolytes were normal, and Lyme's serology was negative. Echocardiogram was normal. Cardiac magnetic resonance imaging (CMR) revealed late gadolinium enhancement (LGE) affecting the mid inferior segment at the right ventricle (RV) insertion site (Figure 1). A cardiac and whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan showed focal areas of increased FDG uptake in the LV involving mid and basal anteroseptal segments, mid inferoseptal segment, basal inferolateral, and basal inferior segments with normal perfusion (Figure 2). The scan also revealed hypermetabolic bilateral hilar and mediastinal lymphadenopathy. A diagnosis of CS was made. An Implantable-Cardioverter-defibrillator (ICD) was placed and the patient was discharged on 40mg of prednisone and 20mg of leflunomide. Within 4 months, he went from 100% RV pacing to 0%. Eventually, the corticosteroid was tapered off. At follow-up after 1.5 years, RV pacing remained 0% on Leflunomide 20mg. DISCUSSION: One should always suspect CS in young patients with high-grade AV block. During the workup of CHB (Figure 3), the 2017 Japanese Circulation Society Working Group Criteria for diagnosing CS was followed (1). The patient had 2 characteristic findings strongly suggestive of sarcoidosis: (a) hilar lymphadenopathy and (b) significant tracer accumulation in the myocardium and hilar lymph nodes on FDG-PET scan. He also met 2 major criteria strongly suggestive of CS: (a) LGE on CMR and (b) abnormal myocardial FDG uptake. These findings, per the criteria, establish the clinical diagnosis of CS. The mainstay of treatment for CS is corticosteroids +/- steroid-sparing agents to decrease intra-cardiac inflammation (1). CHB patients with CS have a high risk of ventricular arrhythmias, hence should receive ICD (2). The addition of antimetabolite adjuvants is more effective than corticosteroids alone (3). They may reduce the total time of glucocorticoid therapy and keep patients in remission. CONCLUSIONS: Clinical diagnosis of CS can be established with FDG-PET imaging and CMR. CS patients with advanced heart block should receive ICD. Corticosteroids are the mainstay of treatment. Immunotherapy is an effective adjunct that can help taper the glucocorticoids and keep patients in remission. Early introduction of these agents should be considered in these patients. REFERENCE #1: 1. Trivieri MG et al. Challenges in Cardiac and Pulmonary Sarcoidosis: JACC State-of-the-Art Review. J Am Coll Cardiol 2020;76:1878-1901 REFERENCE #2: 2. Nordenswan H-K et al. Outcome of Cardiac Sarcoidosis Presenting With High-Grade Atrioventricular Block. Circulation: Arrhythmia and Electrophysiology 2018;11:e006145 REFERENCE #3: 3. Nagai S, Yokomatsu et al. Treatment with methotrexate and low-dose corticosteroids in sarcoidosis patients with cardiac lesions. Intern Med 2014;53:427-33. DISCLOSURES: No relevant relationships by Roy Chung, source=Web Response No relevant relationships by Sachin Kumar, source=Web Response No relevant relationships by Raunak Nair, source=Web Response

Deep neural network for automatic volumetric segmentation of whole-body CT images for body composition assessment

Body composition analysis on CT images is a valuable tool for sarcopenia assessment. We aimed to develop and validate a deep neural network applicable to whole-body CT images of PET-CT scan for the automatic volumetric segmentation of body composition. For model development, one hundred whole-body or torso 18F-fluorodeoxyglucose PET-CT scans of 100 patients were retrospectively included. Two radiologists semi-automatically labeled the following seven body components in every CT image slice, providing a total of 46,967 image slices from the 100 scans for training the 3D U-Net (training, 39,268 slices; tuning, 3116 slices; internal validation, 4583 slices): skin, bone, muscle, abdominal visceral fat, subcutaneous fat, internal organs with vessels, and central nervous system. The segmentation accuracy was assessed using reference masks from three external datasets: two Korean centers (4668 and 4796 image slices from 20 CT scans, each) and a French public dataset (3763 image slices from 24 CT scans). The 3D U-Net-driven values were clinically validated using bioelectrical impedance analysis (BIA) and by assessing the model's diagnostic performance for sarcopenia in a community-based elderly cohort (n=522). The 3D U-Net achieved accurate body composition segmentation with an average dice similarity coefficient of 96.5%-98.9% for all masks and 92.3%-99.3% for muscle, abdominal visceral fat, and subcutaneous fat in the validation datasets. The 3D U-Net-derived torso volume of skeletal muscle and fat tissue and the average area of those tissues in the waist were correlated with BIA-derived appendicular lean mass (correlation coefficients: 0.71 and 0.72, each) and fat mass (correlation coefficients: 0.95 and 0.93, each). The 3D U-Net-derived average areas of skeletal muscle and fat tissue in the waist were independently associated with sarcopenia (P<.001, each) with adjustment for age and sex, providing an area under the curve of 0.858 (95% CI, 0.815 to 0.901). This deep neural network model enabled the automatic volumetric segmentation of body composition on whole-body CT images, potentially expanding adjunctive sarcopenia assessment on PET-CT scan and volumetric assessment of metabolism in whole-body muscle and fat tissues.