Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/computed Tomography Research Articles

Sociodemographic factors and Child Opportunity Index disparities associated with missed care opportunities in pediatric patients with lymphoma and leukemia referred for FDG-PET/CT.

Little data exists on the association of missed care opportunities (MCOs) in children referred for nuclear medicine/nuclearoncology imaging examinations and socioeconomic disparities. To determine the prevalence of MCOs in children with lymphoma/leukemia scheduled for fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and the impact of sociodemographic factors and Child Opportunity Index (COI). Retrospective analysis of MCOs in children with lymphoma/leukemia scheduled for FDG-PET/CT (2012 to 2022)was performed. In univariate analysis, patient, neighborhood, and appointment data were assessed across MCOs and completed appointments. Logistic regression evaluated independent effects of patient-, neighborhood-, and appointment-level factors with MCOs. Two-sided P-value < .05 was considered statistically significant. In 643 FDG-PET/CT appointments (n = 293 patients; median age 15years (IQR 11.0-17.0years); 37.9% female), there were 20 MCOs (3.1%) involving 16 patients. Only 8.2% appointments involved Black/African American non-Hispanic/Latino patients, yet they made up a quarter of total MCOs. Patients living in neighborhoods with very low or low COI experienced significantly higher MCOs versus zip codes with very high COI (6.9% vs. 0.8%; P = 0.02). Logistic regression revealed significantly increased likelihood of MCOs for patients aged 18 to 21 [odds ratio (OR) 4.50; 95% CI 1.53-13.27; P = 0.007], Black/African American non-Hispanic/Latino (OR 3.20; 95% CI 1.08-9.49; P = 0.04), zip codes with very low or low COI (OR 9.60; 95% CI 1.24-74.30; P = 0.03), and unknown insurance status. Children with lymphoma/leukemia, living in zip codes with very low or low COI, and who identified as Black/African American non-Hispanic/Latino experienced more MCOs. Our study supports the need to address intersecting sociodemographic, neighborhood, and health system factors that will improve equitable access to necessary healthcare imaging for children.

Prospective Assessment of Fluorine-18-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography (FDG-PET/CT) for Early Identification of Checkpoint-Inhibitor-Induced Pseudoprogression.

The activity of immune checkpoint inhibitors (ICIs) in patients with metastatic melanoma is often monitored using fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scans. However, distinguishing disease progression (PD) from pseudoprogression (PsPD), where increased FDG uptake might reflect immune cell activity rather than tumor growth, remains a challenge. This prospective study compared the efficacy of dual-time point (DTP) FDG-PET/CT with modified response criteria (PERCIMT) in differentiating PsPD from PD. From July 2017-January 2021, 41 patients suspected to have PsPD on an evaluation scan were prospectively included (29 evaluable). A subsequent DTP FDG-PET/CT scan was conducted within 14 days, followed by a confirmatory FDG-PET/CT scan. Additionally, PERCIMT were applied. DTP FDG-PET/CT identified 24% with PsPD and 76% with PD. Applying PERCIMT criteria, 69% showed PsPD, while 31% had PD. On follow-up, 10 patients (34%) demonstrated confirmed PsPD, while 19 (66%) exhibited PD. The sensitivity and specificity of DTP FDG-PET/CT were 20% and 74%, respectively, and for PERCIMT this was 80% and 37%, respectively. Our findings suggest limited efficacy of DTP FDG-PET/CT in distinguishing PsPD from PD in ICI-treated patients with metastatic melanoma. The use of PERCIMT could complement clinical assessment and be incorporated in multidisciplinary team conferences for enhanced decision-making.

The Role of FDG-PET in the Evaluation of Hidradenitis Suppurativa: A Systematic Review.

Hidradenitis suppurativa (HS) is a chronic skin disorder characterized by nodules, comedones, and sinus tracts that often leave prominent scarring. In recent years, non-invasive imaging techniques have been used to assess the inflammatory activity, vascularization, and treatment response of lesions. Specifically, fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scans may aid in identifying systemic inflammation in patients with HS, improving diagnosis. Inflamed hypermetabolic tissues exhibit a greater uptake of FDG due to increased glucose uptake and vascularity. A systematic review was conducted to summarize the utility of nuclear imaging techniques in the diagnosis and treatment follow-up of HS. PubMed, Scopus, and ScienceDirect databases were utilized for relevant articles discussing the utility of PET scans in managing HS. A total of 51 citations were identified in the initial search. Following the review of titles, abstracts, and duplicates, 43 articles were excluded, leaving a total of eight articles for analysis. Data were extracted from each article, encompassing the number of patients, imaging techniques employed, and final results. An analysis of the data demonstrated that FDG-PET showed evidence of identifying subclinical lesions of the disease, improving the visualization of HS, and providing an objective method of assessing severity.

PET/MR versus PET/CT for locoregional staging of oropharyngeal squamous cell cancer.

The value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for TN staging in head and neck cancer (HNC) has been proven in numerous studies. A few studies have investigated the value of FDG-PET/magnetic resonance imaging (MRI) in the staging of HNC; the combined results indicate potential for FDG-PET/MRI, but the scientific evidence remains weak. To compare performance of FDG-PET/CT and FDG-PET/MRI for locoregional staging in patients with oropharyngeal carcinomas. Two radiologists independently of each other retrospectively reviewed primary pre-therapeutic FDG-PET/CT and FDG-PET/MRI examinations from 40 individuals with oropharyngeal carcinomas. TN stage and primary tumor size were noted. The results were compared between observers and modalities and against TN stage set at a multidisciplinary conference. For nodal staging, PET/MRI had slightly higher specificity and accuracy than PET/CT for the most experienced observer. Both methods demonstrated excellent sensitivity (≥ 0.97 and 1.00, respectively), as well as high negative predictive values (≥ 0.95 and 1.00, respectively). No significant differences were found for tumor staging or measurement of maximum tumor diameter. There was a weak agreement (κ = 0.35-0.49) between PET/CT and PET/MRI for T and N stages for both observers. Inter-observer agreement was higher for PET/MRI than for PET/CT, both for tumor staging (κ = 0.57 vs. 0.35) and nodal staging (κ = 0.69 vs. 0.55). The agreement between observers was comparable to the agreement between methods. PET/MRI may be a viable alternative to PET/CT for locoregional staging (TN staging) and assessment of maximal tumor diameter in oropharyngeal squamous cell cancer.

Role of FDG-PET CT in differentiating adenocarcinomas from squamous cell carcinomas of the lung

Abstract Background Lung cancer is the leading cause of cancer related deaths worldwide. The combination of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) has a great impact on the diagnosis, staging, and hence on the treatment plan and follow up of lung cancer patients. Maximum standardized uptake value (SUVmax) is a semi-quantitative index which is easily performed and the most widely used quantitative parameter for the analysis of 18F-FDG PET images and for the estimation of metabolic activity. Objective to investigate the role of PET/ CT to differentiate between adenocarcinomas (AC) and squamous cell carcinomas (SCC) as the most common lung cancer by comparing their FDG uptake measured in the form of SUVmax. Methods A retrospective observational study, conducted at Ain Shams University Hospitals- Radiology Department patients diagnosed with non-small cell lung cancer (NSCLC) and histopathologically proved to be adenocarcinoma or squamous cell carcinoma. All were investigated using PET/CT scans in the period between June 2017 to September 2019. SUVmax of the lesion were measured and statistically analyzed compared with the histopathological type. Results A total of 30 patients were evaluated with the age ranging from 31 to 81 years old, the mean was 56.9 years (SD ± 11.53). Among them 25 patients (83.3%) were males and 5 patients (16.7%) were females. Out of the 30 NSCLC patients included in the study, 18 patients (60%) were histopathologically diagnosed as AC and 12 patients (40%) were histopathologically diagnosed as SCC. The mean SUVmax of the 30 NSCLC lesions was 15.02±8.4 (range: 2-32.8).The mean SUVmax of AC lesions was 12.4±7.55 (range: 2-32.8), while the mean SUVmax of SCC lesions was 18.95±8.3 (range: 3.7-30.77). The mean SUVmax of lesions in patients with SCC was significantly higher than that of patients with AC using Wilcoxon-Mann-Whitney test (P = 0.04). Conclusion SCC of the lung has higher SUVmax than AC of the lung and it can be used to differentiate between them using PET/CT.

The use of FDG-PET/CT to detect early recurrence after resection of high-risk stage III melanoma.

The role of surveillance imaging in high-risk stage III melanoma patients after complete surgical resection remains controversial, and with the advent of adjuvant therapy, it may also be expanded. Therefore, we evaluated two fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) protocols in two cohorts. Cohort 1 (n = 35) focused on surveillance in asymptomatic patients (before approval and reimbursement of adjuvant therapy) and was assigned to 5x FDG-PET/CT's after surgery: one every 6 months for 2 years, with one final scan after 3 years. Cohort 2 (n = 42) was assigned to one screening FDG-PET/CT, which took place in between surgery and the start of adjuvant treatment. In cohort 1 (median follow-up: 33 months), 12 patients (34.3%) developed recurrence detected by FDG-PET/CT, of which 7 (20.0%) were detected with the first scan. Sensitivity and specificity were 92.3% and 100%, respectively. In cohort 2, recurrence was suspected on nine scans (21.4%) and four (9.5%) were true positive. The number of scans needed to find one asymptomatic recurrence were 8.8 and 10.5 in cohort 1 and 2, respectively. FDG-PET/CT is a valuable imaging tool to detect recurrence in stage III melanoma, even shortly after surgery. A surveillance FDG-PET/CT protocol after surgery or a screening PET/CT before adjuvant therapy should be considered.

In the evaluation of patients with skull base osteomyelitis, does 18F-FDG PET CT have a role?

To evaluate the diagnostic performance of regional fluorine-18 fluorodeoxyglucose (F-FDG) positron emission tomography-computed tomography (PET-CT) in patients with skull base osteomyelitis (SBO) and to compare with magnetic resonance imaging (MRI) whenever available. A total of 77 patients (male:female = 56:21; mean age 66.4 ± 9.4 years) with clinically suspected SBO, who underwent regional F-FDG PET-CT were included in this retrospective study. F-FDG PET-CT images were analyzed for presence, localization and intensity of FDG uptake. Diagnostic performance of F-FDG PET-CT was analyzed based on histopathology, culture, and clinical/imaging follow-up. The agreement analysis between F-FDG PET-CT and MRI findings was performed in 56 patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of F-FDG PET-CT for diagnosing SBO were 96.7, 93.3, 98.3, 87.5, and 96.1%, respectively. The average SUVmax of the lesions was 5.9 ± 3.5. The SUVmax of the fungal lesions was lower than that of bacterial lesions with P-value of <0.001. On comparing variables like C-reactive protein, erythrocyte sedimentation rate, and SUVmax for prediction of recurrence/progression, by plotting an ROC curve, the SUVmax was found to be an independent prognostic marker. 56 out of 77 patients had undergone both F-FDG PET-CT and MRI. The agreement analysis between the modalities showed almost perfect agreement for delineation of soft tissue and bony involvement with κ values of 0.82 and 0.81, respectively. F-FDG PET-CT is a sensitive tool in evaluation of patients with SBO. It shows a very good agreement with the MRI. It plays a critical role in treatment response evaluation.

FDG/PET-CT–Based Lymph Node Atlas in Breast Cancer Patients

The aim of this study was to localize locoregional lymph node metastases using positron emission tomography with fluorine 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) data sets in a large cohort of patients and to evaluate the existing Radiation Therapy Oncology Group (RTOG) clinical target volume (CTV) and the European Society for Radiation Therapy & Oncology (ESTRO) CTV contouring guidelines. A total of 235 patients with 580 FDG/PET-CT positive locoregional lymph node metastases were included in our analysis. The patients were divided into 4 groups according to their course of disease (primary vs recurrent breast cancer) and the presence or absence of distant metastasis at the time of the FDG-PET/CT staging (distant metastasis vs no distant metastasis). All imaging data were imported into the planning system, and each lymph node was manually contoured. A patient with "standard anatomy" was chosen as a template, and all contoured structures were registered rigidly and nonrigidly to this patient. A comprehensive 3-dimensional atlas was created, including all identified lymph node metastases. The incidences of lymph node metastases were analyzed and are presented with color coding in the atlas. Lymph node levels (axillary, internal mammary, supraclavicular) were contoured according to RTOG and ESTRO guidelines and evaluated. The mean volume of the lymph nodes was 1.7±2.6cm3 with an average diameter of 1.3±0.7cm. Most lymph nodes were in level I (n=316; 54.5%) followed by the supraclavicular region (n=80; 13.8%), level II (n=57; 9.8%), level III (n=58; 10.0%), and the internal mammary region (n=55; 9.5%). The covered lymph node volume was 69.8%±35.5% (69.1%±36.3%) for primary breast cancer and 57.6%±38.9% (51.1%±39.1%) for recurrent breast cancer using the RTOG (ESTRO) guidelines. The internal mammary region and supraclavicular region were affected more often in recurrent breast cancer compared with primary breast cancer. The occurrence of lymph node metastases outside the RTOG and ESTRO margins in patients with and without distant metastases was similar. The largest geometric deviations between RTOG/ESTRO CTV contours and lymph node occurrence were measured in the supraclavicular region, the internal mammary region, and level II. The provided lymph node atlas illustrates where lymph node metastases occur in different clinical situations and presents areas at high risk (ie "hot spots" of lymph node metastases).

The Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Bone Lesions of Undetermined Origin.

The aim of the current study was to determine the diagnostic accuracy of whole-body fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in detecting carcinoma of unknown primary (CUP) with bone metastases. We evaluated 87 patients who were referred to FDG-PET/CT imaging and reported to have skeletal lesions with suspicion of malignancy. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. The median survival rate was measured to evaluate the prognostic value of the FDG-PET/CT findings. In the search for a primary, FDG-PET/CT findings correctly diagnosed lesions as the site of the primary true positive (TP) in 64 (73%) cases, 4 (5%) findings diagnosed no site of a primary, and none were subsequently proven to be true negative (TN); 14 (16%) diagnoses were false positive (FP) and 5 (6%) diagnoses were false negative (FN). Life expectancy was between 2 months and 25 months. Whole-body FDG-PET/CT imaging may be a useful method in assessing the bone lesions with suspicion of bone metastases.

Multiparametric whole-body anatomic, functional, and metabolic imaging characteristics of peripheral lesions in patients with schwannomatosis.

To describe the anatomic, functional, and metabolic characteristics of peripheral nerve sheath tumors (PNSTs) in patients with schwannomatosis (SWN) on whole-body magnetic resonance imaging (WB-MRI) (anatomic and functional imaging) and fluorine-18-fluorodeoxyglucose positron emission tomography / computed tomography (FDG-PET/CT) (metabolic imaging). WB-MRIs at 1.5T and 3.0T performed in 13 SWN subjects using short tau inversion recovery (STIR), T1 -weighted (T1 W), contrast-enhanced T1 W, and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping and FDG-PET/CT were retrospectively reviewed. Two readers reviewed all imaging for the presence and character of peripheral lesions (size, imaging features, ADC values, and standardized uptake values [SUVmax ]) and ancillary findings. Descriptive statistics are reported. In all, 153 index lesions were characterized in 13 patients on WB-MRI. Lesions were characterized as tumors (97% [149/153]) or cysts (3% [4/153]); 96% (143/149) PNSTs were solitary while 4% (6/149) were plexiform. The median size was 2.3 cm (range 1-24.3 cm). On T1 W, 99% (148/149) tumors were homogeneously isointense; on STIR, 81% (121/149) tumors were heterogeneously hyperintense; on postcontrast T1 W, 81% (100/123) tumors enhanced heterogeneously; on DWI, tumor ADC values (×10(-3) mm(2) /s) were variable (minimum ADC range 0.3-2.2, average ADC range 0.9-2.9). The median SUVmax was 6 (range 2.1-11.7) and 10 (2.7-15.3) on early and delayed imaging, respectively. Malignant degeneration was detected in 1% (1/149) with suspicious anatomic, functional, and metabolic characteristics. Ancillary findings included nerve root thickening (23% [3/13]) and spinal canal lesions (15% [2/13]). Although the majority of the PNSTs in SWN are benign and solitary, PNSTs can be plexiform, enlarge over time, and, rarely, undergo malignant degeneration. Due to the high metabolic activity in benign PNSTs by FDG-PET/CT in SWN, WB-MRI with functional sequences maybe a more suitable technique for the assessment of disease burden, tumor characterization, and surveillance. J. MAGN. RESON. IMAGING 2016;44:794-803.

Large vessel vasculitis in elderly patients: early diagnosis and steroid-response evaluation with FDG-PET/CT and contrast-enhanced CT

Large vessel vasculitis (LVV) is an often-reported cause of inflammation of unknown origin (IUO) in elderly people. The objective of this study was to describe the usefulness of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and contrast-enhanced CT in early diagnosis and treatment follow-up of patients with LVV presenting as elderly onset IUO. We retrospectively compared contrast-enhanced CT findings and FDG-PET/CT findings of the patients diagnosed with LVV and 11 controls; all subjects were 50 years of age or older. We evaluated maximum standardised uptake value (SUV(max)) and PET score of the aortic wall for quantitative comparison of FDG-PET/CT findings. We measured the aortic wall thickness (W) and its ratio against the radius (W/R) for quantitative comparison of aortic wall thickening by contrast-enhanced CT. After steroid treatment, we compared these values with those pre-treatment. Of 124 patients who were hospitalised due to advanced age and IUO, 88 underwent FDG-PET/CT and contrast-enhanced CT. Abnormal findings were observed on images from 78 patients. The findings were indicative of LVV in 13 patients (10.5 %), of whom more than half had only non-specific symptoms. Patients with LVV had significantly higher aortic wall SUV(max) (3.85 vs. 1.95), PET scores by FDG-PET/CT, and aortic wall thicknesses by contrast-enhanced CT (3.8 vs. 2.6 mm) than controls. Significant improvement in aortic wall thickening was evidenced by reduced PET scores and by contrast-enhanced CT findings in patients who were followed up after treatment. LVV is an important cause of IUO with non-specific symptoms in elderly patients. Imaging examination comprising contrast-enhanced CT and FDG-PET/CT is useful for early diagnosis and early treatment evaluation of LVV, allowing for amelioration of reversible aortic wall thickening.

An Unusual Case of Epigastric and Back Pain

A 63-year-old African woman immigrated to Europe presented to our hospital with increasing epigastric pain radiating to back, unresponsive to proton-pump inhibitors, lasting for a week. There was no nausea, vomiting, diarrhea, or fever. History was positive for diabetes mellitus, hypertension, and previously treated pulmonary tuberculosis. On examination, the patient was afebrile, and there was no lymphadenopathy. Amylase and lipase levels were normal, whereas erythrocyte sedimentation rate (120 mm/h) and C-reactive protein (14 mg/dL) were increased. Superior endoscopy showed normal findings; abdominal ultrasound was negative. Computed tomography (CT) angiography revealed a 10×23-mm saccular aneurysm of thoracic aorta (D9 level) with localized dissection and thickening of the aortic wall (Figure 1). There was lymph node enlargement at hilum and along bronchopulmonary, thoracic, and lumbosacral chains. Apical pleural thickness and …

Potential Role of Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Immunoglobulin G4-related Systemic Disease

We report on a 60-year-old man who presented with painless obstructive jaundice, suspicious of hilar cholangiocarcinoma. Positron emission tomography–computed tomography (PET-CT) demonstrated markedly fluorodeoxyglucose-avid bilateral enlarged submandibular masses and extensive hypermetabolic supra- and infra-diaphragmatic lymphadenopathy. Left submandibular excisional biopsy revealed immunoglobulin G4related systemic disease. Compared with CT or magnetic resonance imaging, fluorine-18 fluorodeoxyglucose PET-CT not only allows whole-body imaging, but also offers metabolic information that helps to reflect disease activity. Fluorine-18 fluorodeoxyglucose PET-CT is a potential useful tool for diagnosis, treatment response assessment, and relapse detection of this systemic disease that is worth further exploration.

Clinical implications of initial FDG-PET/CT in locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

The present study evaluated the predictive and prognostic impact of initial fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in patients with locally advanced rectal cancer treated with neoadjuvant concurrent chemoradiotherapy (CCRT). Eighty-one consecutive patients with locally advanced rectal cancer (cT3-T4 N-/N+) treated with neoadjuvant CCRT were enrolled. The FDG-PET/CT parameters, including the SUVmax, metabolic tumor volume (MTV, 50 % of SUVmax), and multiplication of the SUVmean and MTV (total lesion glycolysis, TLG), were analyzed in relation to the pathologic response and disease recurrence. Five patients (6.2 %) achieved a pathologic complete response (pCR) after CCRT followed by surgery. None of the FDG-PET/CT parameters was identified as a predictive factor for pCR. After a median follow-up period of 26.7 (range 10.9-63.3) months, 19 patients (23.5 %) presented a local and/or distant recurrence. In a multivariate analysis including the clinicopathologic parameters, the TLG of the primary tumor was associated with a worse disease-free survival after neoadjuvant CCRT (HR 20.035, 95 % CI 1.726-232.559; P = 00.017). The TLG of the primary tumor in the initial FDG-PET/CT can be considered as a prognostic factor for patients with locally advanced rectal cancer treated with neoadjuvant CCRT.

Comparison of the effectiveness of MRI perfusion and fluorine-18 FDG PET-CT for differentiating radiation injury from viable brain tumor: a preliminary retrospective analysis with pathologic correlation in all patients

ObjectivesDifferentiating radiation injury from viable tumor is important for optimizing patient care. Our aim was to directly compare the effectiveness of fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography–computed tomography (PET-CT) and dynamic susceptibility-weighted contrast-enhanced (DSC) magnetic resonance (MR) perfusion in differentiating radiation effects from tumor growth in patients with increased enhancement following radiotherapy for primary or secondary brain tumors. Materials and methodsWe retrospectively identified 12 consecutive patients with primary and secondary brain tumors over a 1-year period that demonstrated indeterminate enhancing lesions after radiotherapy and that had undergone DSC MR perfusion, FDG PET-CT, and subsequent histopathologic diagnosis. The maximum standardized uptake value (SUV) of the lesion (SUVlesion max), SUVratio (SUVlesion max/SUVnormal brain), maximum relative cerebral blood volume, percentage of signal intensity recovery, and relative peak height were calculated from the positron emission tomography and MR perfusion studies. A prediction of tumor or radiation injury was made based on these variables while being blinded to the results of the surgical pathology. ResultsSUVratio had the highest predictive value (area under the curve=0.943) for tumor progression, although this was not statistically better than any MR perfusion metric (area under the curve=0.757–0.829). ConclusionsThis preliminary study suggests that FDG PET-CT and DSC MR perfusion may demonstrate similar effectiveness for distinguishing tumor growth from radiation injury. Assessment of the SUVratio may increase the sensitivity and specificity of FDG PET-CT for differentiating tumor and radiation injury. Further analysis is needed to help define which modality has greater predictive capabilities.

Coexistence of physiologic and abnormal muscle uptake of fluorine-18-fluorodeoxyglucose in a patient with plasma cell leukemia.

Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) performed for restaging in a 70-year-old male patient with history of plasma cell leukemia (PCL) showed increased symmetrical and asymmetrical fluorine-18-fluorodeoxyglucose (FDG) uptake in some muscular groups. Magnetic resonance imaging showed structural abnormalities in the area of asymmetrical muscle uptake at FDG-PET/CT. Symmetrically increased FDG uptake was considered of functional significance. The pattern of muscle uptake at FDG-PET and the presence of concomitant abnormalities at the corresponding CT scan were useful to discriminate between physiological and abnormal findings in this patient with PCL (Figs. 1, ​,22 and ​and33). Fig. 1 A 70-year-old male patient previously treated for plasma cell leukemia (PCL), secondary to multiple myeloma, was referred to our institute because of the onset of low back pain radiating to the left leg and walking difficulties (the patient was on a wheelchair). ... Fig. 2 Axial CT (first column), PET (second column) and PET/CT (third column) showed multiple areas of symmetrically increased FDG uptake corresponding to several muscle groups (yellow arrows), without any significant abnormalities at the corresponding CT scan. ... Fig. 3 Axial PET (first row), CT (second row) and PET/CT (third row) images showed also the presence of an area of asymmetrical increased FDG uptake corresponding to the left gluteus medius muscle (red arrows), with a SUVmax of 7.9. CT scan demonstrated swelling ...

The Predictive Role of Sequential FDG-PET/CT in Response of Locally Advanced Rectal Cancer to Neoadjuvant Chemoradiation

This study prospectively assessed the value of sequential fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scans for predicting the response of locally advanced rectal cancer to neoadjuvant chemoradiation. Fifty consecutive patients with locally advanced rectal cancer were enrolled. The treatment consisted of concurrent chemoradiation, which included preoperative 5-fluorouracil-based chemotherapy and pelvic radiation (4500 to 5040 cGy); this was followed 8 weeks later (median: 55 d) by surgery with a curative intent. All the patients underwent FDG-PET/CT before and 5 weeks later (median: 35 d) after the completion of chemoradiation. We evaluated the measurements of the FDG uptake [maximum standardized uptake values (SUV(max))] and the percentage of SUV(max) difference [(response index (RI)] between the prechemoradiation and postchemoradiation FDG-PET/CT scans. After chemoradiation, 32 of 50 patients (64%) were classified as responders according to the tumor regression grade, which is based on the ratio of fibrosis to residual cancer (tumor regression grade 3-4). For all the patients, the mean prechemoradiation SUV(max) was 14.8, and this was significantly higher than the mean SUV(max) value of 6.1 at postchemoradiation (P< 0.001). The mean RI was significantly higher in the responders than that in the nonresponder patients (62.6% vs. 31.2%, P = 0.001). The following parameters were obtained using a RI cutoff of 53.0% for defining a response to therapy: 75.0% sensitivity, 73.2% specificity, 82.8% positive predictive value, and 61.9% negative predictive value. The FDG-PET/CT parameters, and especially the RI, may be best for assessing the neoadjuvant chemoradiation response of locally advanced rectal cancer and these values can potentially assist physicians for planning the optimal treatment.

Primary penile lymphoma: 18f-fdg pet-CT for accurate staging and response monitoring

Primary penile lymphoma is an extremely rare neoplasm. We present a case of 63-year-old man with painless diffuse pe- nile swelling and retention of urine. Biopsy from the penile swelling demonstrated CD20+ diffuse large B-cell lymphoma. Staging was performed using fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and revealed a FDG avid penile mass with enlarged and FDG avid multiple inguinal and aortocaval lymph nodes. A follow-up FDG PET-CT scan after eight cycles of combination chemotherapy showed complete remission of the dis- ease. Thus, FDG PET-CT should be integrated in management protocols of rare primary penile lymphoma.

Ce-CT versus integreted pet/ct in preoperative nodal staging of non–small cell lung cancer

The purpose of this study was to retrospectively evaluate the effectiveness of integrated positron emission tomography-computed tomography (PET-CT) in comparison with contrast enhanced CT (CE-CT) in pre-operative staging of non-small cell lung cancer (NSCLC) by using surgical and pathological findings as the reference standard. From August 2008 to August 2009, 57 consecutive patients (50 males and 7 females; mean age, 59 years; range, 38-79 years) with NSCLC underwent conventional pre-operative lung cancer staging using clinical data and CE-CT of the chest, and integrated whole-body fluorine-18 fluorodeoxyglucose PET-CT studies. Histopathological results served as the reference standard. Forty-eight of the 57 patients (84%) had no lymph node involvement (N0), five (9%) were found to have N1 disease, and four (7%) had N2 disease. There was a significant difference between CE-CT and PET-CT for nodal staging of N0 disease (P < 0.05). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of hilar and mediastinal lymph node staging were 56%, 73%, 28%, 90%, and 70%, with CE-CT, respectively; and 78%, 92%, 64%, 96%, and 89% with PET-CT, respectively. Integrated PET-CT is more accurate than CE-CT for lymph node staging in NSCLC.

Measuring diffuse metabolic activity on FDG-PET/CT: new method for evaluating Langerhans cell histiocytosis activity in pulmonary parenchyma

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare cause of interstitial lung disease characterized by formation of nodules in the active phase of the disease that evolve into nonactive cystic lesions later on. To evaluate PLCH activity in patients, we developed a new method for measuring diffuse metabolic activity on fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) using a lung-to-liver activity ratio. We retrospectively studied a series of 4 FDG-PET and 23 FDG-PET/CT scans from 7 patients with PLCH and analyzed a sample of 100 randomly chosen FDG-PET/CT studies free from any known lung or hepatic diseases. Maximum standardized uptake value (SUVmax) in a spherical volume (6-8 cm in diameter) in the right lung was put into relation with SUVmax in a spherical volume (9-10 cm in diameter) in the reference liver parenchyma to set up the SUVmaxPULMO/SUVmaxHEPAR index. The index values were compared to the disease course in each patient. In patients with PLCH, a close correlation between the index value and the disease course was found in all seven subjects, where the increasing index values indicated disease activity, while decreasing index values were observed after therapy administration. In the group of 100 healthy control subjects, we found index values lower than 0.3 in 80% and lower than 0.4 in 96% [range: 0.14-0.43; 0.24±0.07 (100)]. Measuring SUVmaxPULMO/SUVmaxHEPAR values and their time-trend monitoring represent simple, noninvasive screening tools allowing an early diagnosis and treatment response follow-up assessment in patients with PLCH.