Whole-body 18F-fluorodeoxyglucose Positron Emission Research Articles

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.

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.

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.

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.

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.

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.

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.

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

The prognostic value of 18F-fluorodeoxyglucose positron emission tomography/ computed tomography parameters in patients with malignant pleural mesothelioma.

Background In this study, we aimed to investigate the prognostic value of metabolic 18F-fluorodeoxyglucose positron emission tomography/computed tomography parameters in malignant pleural mesothelioma patients. Methods A total of 65 patients with malignant pleural mesothelioma (34 males, 31 females; median age: 60 years; range, 39 to 84 years) who underwent whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography for staging before treatment between March 2008 and January 2018 were included. Relationships between clinicopathological factors and 18F-fluorodeoxyglucose positron emission tomography/computed tomography parameters and overall survival were evaluated using a log-rank test and Cox regression analysis. Results The median follow-up was 13 (range, 4 to 55) months. The Kaplan-Meier analysis revealed a mean survival time of 17±2.6 months. The cumulative two- and five-year survival rates were 34.8% and 7.8%, respectively. Univariate analysis showed that ≥60 age, left hemithorax involvement, a maximum standardized uptake value of ≥9.8, c-T4 status, c-M1 status, and non-surgery were negatively associated with overall survival (p<0.05). Multivariate analysis showed that ≥60 age, left hemithorax involvement, a maximum standardized uptake value of ≥9.8, c-M1 status, and a total lesion glycolysis of ≥180.2 g were negatively associated with overall survival (p<0.05). Conclusion Metabolic parameters of 18F-fluorodeoxyglucose positron emission tomography/computed tomography have the potential to provide prognostic information for malignant pleural mesothelioma patients who are receiving surgery and/or chemotherapy.

Evaluation of a model-based attenuation correction method on whole-body 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging

The bone cannot be evaluated using magnetic resonance attenuation correction (MRAC) with the Dixon sequence. To solve this issue, the present study aimed to evaluate model-based AC for whole-body 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) by creating bone segmentation. We analyzed and evaluated the data of 31 consecutive patients. The Biograph mMR (Siemens Healthcare) was used for clinical whole-body 18F-FDG PET/MRI with the conventional MRAC method, and OSIRIX MD software was used to analyze the images. After the examination, the new model-based post-processing MRAC was applied to create μ-maps with bone segmentation, and retrospective PET reconstruction was performed using this μ-map. The bone structures of all patients created using model-based MRAC were visually evaluated. Standard uptake values (SUVs) at 11 anatomical positions in PET images, corrected using the μ-map with and without bone segmentation, were measured and compared. The model-based post-processing MRAC was run for all patients, without errors. Visual evaluation revealed that the model-based post-processing MRAC exhibited poor results for six patients. Furthermore, it exhibited an increasing trend of SUV in the brain compared to the conventional method. Locations other than the brain indicated a similar or decreasing trend. The two methods showed a good linear correlation for all patients. However, patients aged < 20years exhibited a different trend from those aged ≥ 20years. We should exercise caution when applying this model-based MRAC for younger patients.

Metabolically Active Subacute Infarct Masquerading as Metastasis: A Finding not to be overlooked in Asymptomatic Oncology Patients.

A 50-year-old man with carcinoma of the right buccal mucosa underwent staging whole-body 18F-fluorodeoxyglucose positron emission tomography–computed tomography, which revealed a hypermetabolic heterogeneously enhancing lobulated primary lesion in the right buccal region and an incidental finding of subacute stroke. The case highlights the importance of discriminating brain neoplasms mimicking stroke from true ischemic stroke, which is crucial for appropriate management of patients in an oncology setting.

The Impact of Metabolic Activity of Vertebra and Amygdala on Stroke Recurrence

Background: We investigated whether the metabolic activities of the vertebrae and amygdala are related to future vascular events after cerebral infarction. Methods: Between August 1, 2015 and February 28, 2020 patients admitted with acute cerebral infarction and carotid atherosclerosis were included. They underwent whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG PET). We compared the FDG uptake in the internal carotid artery, vertebrae, spleen and amygdala between patients with and without stroke recurrence. Cox proportional hazards model was used to identify factors related to stroke recurrence. Findings: A total of 110 stroke patients were included (mean age=73 years, 43 female). During the median follow-up period of 18 months, 15 patients experienced stroke recurrence. Patients with recurrent stroke were more likely to have diabetes mellitus, lower estimated glomerular filtration rate, and a higher degree of internal carotid artery stenosis than in those without. Patients with recurred stroke also had a significantly higher glucose uptake in the vertebrae (1·14±0·28 versus 1·36±0·40, p=0·009 by t-test) and amygdala (1·01±0·11 versus 1·09±0·14, p=0·017) than those without. The vertebral FDG uptake correlated with bone mineral density and C-peptide level. The FDG uptake in the amygdala was correlated with the monocyte lymphocyte ratio, but not with the vertebral FDG uptake. The Cox proportional hazard model showed that a higher FDG uptake in the vertebrae was independently associated with stroke recurrence (hazard ratio=4·94, 95% confidence interval=1·29 – 18·9), and a higher FDG uptake in the amygdala with overall vascular events (hazard ratio=3·11, 95% confidence interval=1·11 – 8·70). Interpretation: The increased metabolic activities of the vertebrae and amygdala are related to stroke recurrence and overall vascular event, possibly by elevated insulin resistance and innate immune response. Funding Statement: The study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF- 2019R1F1A1059455). Declaration of Interests: None. Ethics Approval Statement: This study was reviewed and approved by the institutional review board of Chung-Ang University Hospital (C2015061) and was registered in the Clinical Research Information Service (Registration no.: 170602-001) as a part of the International clinical Trials Registry Platform of the World Health Organization supported by Korea centers for Disease Control and Prevention.

Whole-Body versus Routine Skull Base to Mid-thigh 18F-Fluorodeoxyglucose Positron Emission Tomography/ Computed Tomography in Patients with Malignant Melanoma

Objectives:The objectives of this study are to assess the utility of whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) (skull vertex to toes) imaging relative to the standard field of view (skull base to mid-thigh) in patients with primary melanoma site that is not located in the lower extremities.Material and Methods:The primary site of the melanoma and metastatic disease was determined based on 18F-FDG PET/CT findings in 26 patients. The FDG avid sites were tabulated as the primary site, lower extremity, brain, and other sites. The hypothesis is that routine skull base to mid-thigh versus whole-body 18F-FDG PET/CT in patients with malignant melanoma will not change management.Results:Patients (26) were divided into those with primary melanoma site in either the lower extremities (six patients) or other site (20 patients). Four of the six patients with the primary site in the lower extremities also had positive findings in the ipsilateral inguinal lymph nodes. One of the patients with a positive inguinal lymph node had metastatic sites in the external iliac region and lungs on the initial study. On follow-up imaging, this patient also exhibited diffuse metastatic disease, including a lower extremity. None of the remaining patients in this group had positive findings other than the primary site in the lower extremity. Of the remaining 20 patients with the primary site not in the lower extremity, one had diffuse metastatic disease that included a lower extremity. However, lower extremity involvement would not change patient management in this case. A second patient in this group had diffuse metastatic disease that also involved the brain. However, no metastatic disease was present in the lower extremities in this patient. None of the remaining 18 patients in this group had metastatic disease in a lower extremity. Two patients in the entire study group of 26 had brain metastasis on contrast-enhanced head CT, with one having multiple brain metastasis. PET failed to demonstrate some of the brain lesions. In the other patient with solitary brain metastasis detected on contrast-enhanced head CT, PET was negative.Conclusion:18F-FDG PET/CT imaging of the lower extremity may not be justified if the primary neoplasm is not located in the lower extremities. Elimination of lower extremity imaging will reduce scanning time and additional radiation exposure. Similarly, PET/CT imaging of the brain may not be justified if contrast-enhanced CT or magnetic resonance imaging of the head is already obtained since these are more sensitive.

Features and clinical impact of extra-cardiac lesions with 18F-fluorodeoxyglucose positron emission tomography in patients with suspected cardiac sarcoidosis.

BackgroundSarcoidosis is a systemic inflammatory disorder and can often affect any other organs beyond the heart. Whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is used to detect not only cardiac but also extra-cardiac involvement of sarcoidosis. However, the features and clinical impact of extra-cardiac lesions have not yet been fully elucidated. Therefore, this study aimed to clarify these using FDG-PET.Methods and resultsWe enrolled 120 consecutive patients with abnormal findings clinically suggesting cardiac sarcoidosis who underwent whole-body FDG-PET. In this study, a patient with suspected cardiac sarcoidosis was defined as one having both clinically suspected findings and FDG-PET positive cardiac uptake. Subsequently, a total of 36 patients with suspected cardiac sarcoidosis were found and analyzed. Extra-cardiac involvement was detected in 35 lesions of 14 patients (39% per patient). In particular, the extra-cardiac lesions were widely distributed throughout the body, and mediastinal/hilar lymph node involvement was most commonly observed. In most of the patients (93% per patient, 13/14), the extra-cardiac lesions were localized in the regions that were considered more accessible with less risk of complication compared with endomyocardial biopsy (EMB). Based on the FDG-PET findings, 8 patients underwent extra-cardiac biopsy without complication, and its diagnostic sensitivity for histological sarcoidosis was high (75%, 6/8). Moreover, FDG-PET-guided extra-cardiac biopsy could confirm histological sarcoidosis in 4 lesions that EMB failed to prove.ConclusionsExtra-cardiac involvement in patients with suspected cardiac sarcoidosis was relatively high. FDG-PET-guided extra-cardiac biopsy may be safe and useful for the imaging based diagnosis of cardiac sarcoidosis.

Development of diffuse large B-cell lymphoma after sofosbuvir-ledipasvir treatment for chronic hepatitis C: A case report and literature review.

Recently, treatments for chronic hepatitis C virus (HCV) infection have significantly improved by the development of direct-acting antiviral agents (DAAs) and almost all patients with HCV can complete antiviral treatment without apparent adverse events. Malignant lymphoma, particularly B-cell non-Hodgkin's lymphoma, is one of the extrahepatic manifestations associated with chronic HCV infection. The effectiveness of anti-HCV therapy with DAAs for B-cell non-Hodgkin's lymphoma has been demonstrated in recent reports, whereas late-onset B-cell non-Hodgkin's lymphoma after HCV eradication with DAAs has occasionally been reported. In the present study, a 77-year-old man with chronic hepatitis C and intermediate liver cancer risk received sofosbuvir-ledipasvir treatment for 12 weeks. Two months following the end of antiviral therapy, he had achieved sustained virologic response for 8 weeks. However, the patient occasionally found swelling of the right cervical lymph nodes without any subjective symptoms. Lymph node biopsy revealed diffuse large B-cell lymphoma and whole-body 18F-fluorodeoxyglucose (FDG) positron emission tomography with computed tomography showed increased FDG uptake in the right cervical, right submandibular, mediastinal and mesenteric lymph nodes. The patient received six courses of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone chemotherapy and achieved complete response at 8 months after chemotherapy initiation. Thus, the development of lymphoid malignancies may arise, even after HCV eradication with DAAs. Therefore, clinicians should be aware of such risks during and after antiviral treatment with DAAs.

Clinical usefulness of FDG-PET/CT for identification of abnormal extra-cardiac foci in patients with infective endocarditis.

The aim of the study was to evaluate the ability to detect extra-cardiac foci by means of whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in patients with definite endocarditis (IE) according to the modified Duke criteria and investigate the clinical impact of the findings. From January 2011 to December 2015 we included 178 patients (mean age 66 ± 14years, 25% female) with IE in this multicentre study. FDG-PET/CT was part of the work-up for extra-cardiac foci in the including hospitals and was performed at a median of 9days (IQR 10) after IE was diagnosed. In 114 patients FDG-PET/CT identified 166 lesions: 52 (31%) infectious lesions, 21 (13%) cases of cancer, 7 (4%) cases of embolism, 60 (36%) reactive findings, and 26 (16%) other types of lesions. A total of 74 new extra-cardiac findings, not previously discovered by other modalities, were identified in 62 patients and resulted in additional investigations in 29 patients and a change in treatment in 18 patients (10%). The most frequent diagnoses discovered by FDG-PET/CT were colon polyps, cancer, and spondylodiscitis. There was a higher rate of findings leading to a change in treatment in patients above 67years of age infected with other bacterial aetiologies than streptococci. FDG-PET/CT was useful to detect extra-cardiac foci. FDG-PET/CT findings may lead to unnecessary investigations. One out of 10 the patients with definite endocarditis had underwent a change in treatment regimen based on the FDG-PET/CT findings.