Positron Emission Tomography-computed Tomography Studies Research Articles

18F-fluorodesoxyglucose positron emission tomography/computed tomography in extramedullary multiple myeloma

18F-fluorodesoxyglucose positron emission tomography/ computed tomography (PET-CT) has a high sensitivity and specificity to detect medullary and extramedullary lesions in multiple myeloma (MM). To describe the findings of PET-CT in extramedullary multiple myeloma (EMM) at diagnosis and at relapse, and correlate its results with clinical variables, response to treatment and survival. Review of medical records and PET-CT reports of 39 patients with multiple myeloma (MM) who had at least one PET-CT study, treated between January 1, 2015, and January 1, 2019 at a clinical hospital. The Standard Uptake Values for each hypermetabolic lesion were not described in PET-CT reports. Fifteen patients had an EMM and in eight, without a previous clinical suspicion, PET-TC lead to the diagnosis. The mortality rate in the 39 patients with MM was 46%. Sixty seven percent of deaths occurred in patients with EMM. PET-TC was useful to diagnose EMM. However, a standardization in PETCT reports would be required to unify criteria. As previously reported, EMM had a greater aggressiveness and lower survival.

Shoulder adhesive capsulitis in cancer patients undergoing positron emission tomography - computed tomography and the association with shoulder pain.

BACKGROUNDAdhesive capsulitis is a relatively common condition that can develop in cancer patients during treatment. Positron emission tomography - computed tomography (PET-CT) is routinely performed as a follow-up study in cancer patients after therapy. Being aware of PET-CT findings to suggest shoulder adhesive capsulitis may help to alert clinicians for the diagnosis of unsuspected shoulder capsulitis.AIMTo assess the association of shoulder adhesive capsulitis with cancer/therapy type and symptoms in cancer patients undergoing PET-CT.METHODSOur prospective study received Institutional Review Board approval. Written informed consent was obtained from all patients, who answered a questionnaire regarding shoulder pain/stiffness at the time of PET-CT study, between March 2015 and April 2019. Patients with advanced glenohumeral arthrosis, metastatic disease or other mass in the shoulder, or shoulder arthroplasty were excluded. Patterns of shoulder capsule 18F-fluorodeoxyglucose (FDG) uptake were noted. Standard Uptake Value (SUV)max and SUVmean values were measured at rotator interval (RI) and deltoid muscle in bilateral shoulders. Normalized SUV (SUV of RI/SUV of deltoid muscle) was also calculated. We assessed if SUV values are different between symptomatic and asymptomatic patients in both shoulders. Covariates were age, gender, and therapy type (surgery, chemotherapy, radiation). Wilcoxon rank sum tests were used to compare unadjusted marginal differences for age, SUV measurements between symptomatic and asymptomatic patients. Multiple linear regression models were used to examine the relationship between right or left shoulder SUV measurements and symptom status, after adjusting for covariates. Statistical significance level was set at P < 0.05.RESULTSOf 252 patients initially enrolled for the study (mean age 66 years, 67 symptomatic), shoulder PET-CT data were obtained in 200 patients (52 were excluded due to exclusion criteria above). The most common cancer types were lymphoma (n = 61), lung (n = 54) and breast (n = 53). No significant difference was noted between symptomatic and asymptomatic patients in terms of age, gender, proportion of patients who had surgical therapy and radiation therapy. A proportion of patients who received chemotherapy was higher in patients who were asymptomatic in the right shoulder compared to those symptomatic in the right shoulder (65% vs 48%, P = 0.012). No such difference was seen for the left shoulder. In both shoulders, SUVmax and SUVmean were higher in symptomatic shoulders than asymptomatic shoulders (Left SUVmax 2.0 vs 1.6, SUVmean 1.6 vs 1.3, both P < 0.002; Right SUVmax 2.2 vs 1.8, SUVmean 1.8 vs 1.5, both P < 0.01). For lung cancer patients, bilateral RI SUVmax and SUVmean values were higher in symptomatic shoulders than asymptomatic shoulders. For other cancer patients, symptomatic patients had higher left RI SUVmax/mean than asymptomatic patients after adjustment.CONCLUSIONIn symptomatic patients metabolic activities in RI were higher than asymptomatic patients. Adhesive capsulitis should be considered in cancer patients with shoulder symptoms and positive FDG uptake in RI.

Fluorodeoxyglucose-avid thyroid incidentaloma

Positron emission tomography–computed tomography (PET-CT) has become a standard investigation oncology workup.18F-fluorodeoxyglucose (18F-FDG) is the main radiopharmaceuticals for most of the studies. Since malignant cells overexpress glucose transporter receptors, they internalize FDG, and FDG undergoes the first rate-limiting step of glycolysis to form FDG-6-phosphate. In a whole-body PET-CT study, a lot of incidental findings are noticed and often bear significant clinical relevance. A normal thyroid gland does not show any demonstrable FDG uptake. However, sometimes, a normal-looking thyroid gland shows up increased FDG uptake in a diffuse manner in both lobes without any obvious focal FDG-avid lesion. This is attributed to autoimmune lymphocytic thyroid diseases and hypothyroidism. A hyperthyroid gland may appear diffusely enlarged with intense FDG uptake throughout the gland suggesting the hyperfunctioning of its follicular cells. However, any focal FDG uptake in either lobe of the thyroid needs an evaluation, particularly if there is any hypodense nodule on corresponding CT study. It is observed that FDG-avid thyroid nodules can harbor malignancy in almost 33% of cases. Hence, any FDG-avid incidentaloma needs an image-guided fine-needle aspiration cytology to rule out occult malignancy.

Whole-body and adipose tissue-specific mechanisms underlying the metabolic effects of fibroblast growth factor 21 in the Siberian hamster

ObjectiveFibroblast growth factor 21 (FGF21) has been shown to rapidly lower body weight in the Siberian hamster, a preclinical model of adiposity. This induced negative energy balance mediated by FGF21 is associated with both lowered caloric intake and increased energy expenditure. Previous research demonstrated that adipose tissue (AT) is one of the primary sites of FGF21 action and may be responsible for its ability to increase the whole-body metabolic rate. The present study sought to determine the relative importance of white (subcutaneous AT [sWAT] and visceral AT [vWAT]), and brown (interscapular brown AT [iBAT]) in governing FGF21-mediated metabolic improvements using the tissue-specific uptake of glucose and lipids as a proxy for metabolic activity. MethodsWe used positron emission tomography-computed tomography (PET-CT) imaging in combination with both glucose (18F-fluorodeoxyglucose) and lipid (18F-4-thiapalmitate) tracers to assess the effect of FGF21 on the tissue-specific uptake of these metabolites and compared responses to a control group pair-fed to match the food intake of the FGF21-treated group. In vivo imaging was combined with ex vivo tissue-specific functional, biochemical, and molecular analyses of the nutrient uptake and signaling pathways. ResultsConsistent with previous findings, FGF21 reduced body weight via reduced caloric intake and increased energy expenditure in the Siberian hamster. PET-CT studies demonstrated that FGF21 increased the uptake of glucose in BAT and WAT independently of reduced food intake and body weight as demonstrated by imaging of the pair-fed group. Furthermore, FGF21 increased glucose uptake in the primary adipocytes, confirming that these in vivo effects may be due to a direct action of FGF21 at the level of the adipocytes. Mechanistically, the effects of FGF21 are associated with activation of the ERK signaling pathway and upregulation of GLUT4 protein content in all fat depots. In response to treatment with FGF21, we observed an increase in the markers of lipolysis and lipogenesis in both the subcutaneous and visceral WAT depots. In contrast, FGF21 was only able to directly increase the uptake of lipid into BAT. ConclusionsThese data identify brown and white fat depots as primary peripheral sites of action of FGF21 in promoting glucose uptake and also indicate that FGF21 selectively stimulates lipid uptake in brown fat, which may fuel thermogenesis.

Diagnostic performance of a streamlined 18F-choline PET-CT protocol for the detection of prostate carcinoma recurrence in combination with appropriate-use criteria

To evaluate the efficacy of single time-point half-body (skull base to thighs) fluorine-18 choline positron emission tomography-computed tomography (PET-CT) compared to a triple-phase acquisition protocol in the detection of prostate carcinoma recurrence. Consecutive choline PET-CT studies performed at a single tertiary referral centre in patients with biochemical recurrence of prostate carcinoma between September 2012 and March 2017 were reviewed retrospectively. The indication for the study, imaging protocol used, imaging findings, whether management was influenced by the PET-CT, and subsequent patient outcome were recorded. Ninety-one examinations were performed during the study period; 42 were carried out using a triple-phase protocol (dynamic pelvic imaging for 20 minutes after tracer injection, half-body acquisition at 60 minutes and delayed pelvic scan at 90 minutes) between 2012 and August 2015. Subsequently following interim review of diagnostic performance, a streamlined protocol and appropriate-use criteria were introduced. Forty-nine examinations were carried out using the single-phase protocol between 2015 and 2017. Twenty-nine (69%) of the triple-phase studies were positive for recurrence compared to 38 (78%) of the single-phase studies. Only one patient who had a single-phase study would have benefited from a dynamic acquisition, they have required no further treatment or imaging and are currently under prostate-specific antigen (PSA) surveillance. Choline PET-CT remains a useful tool for the detection of prostate recurrence when used in combination with appropriate-use criteria. Removal of dynamic and delayed acquisition phases reduces study time without adversely affecting accuracy. Benefits include shorter imaging time which improves patient comfort, reduced cost, and improved scanner efficiency.

Validating an image segmentation program devised for staging lymphoma.

Hybrid positron emission tomography-computed tomography (PET-CT) imaging systems are an important tool for assessing the progression of lymphoma. PET-CT systems offer the ability to quantitatively assess lymphocytic bone involvement throughout the body. There is no standard methodology for staging lymphoma patients using PET-CT images. Automatic image segmentation algorithms could offer medical specialists a means to evaluate bone involvement from PET-CT images in a consistent manner. To devise and validate an image segmentation program that may assist staging lymphoma by determining the degree of bone involvement based from PET-CT studies. A custom-made program was developed to segment regions-of-interest from images by utilising an enhanced fuzzy clustering technique that incorporates spatial information. The program was subsequently tested on digital and physical phantoms using four different performance metrics before being employed to extract the bony regions of clinical PET-CT images acquired from 248 patients staged for lymphoma. The algorithm was satisfactorily able to delineate regions-of-interest within all phantoms. When applied to the clinical PET-CT images, the algorithm was capable of accurately segmenting bony regions in less than half of the subjects (n = 103). The performance of the algorithm was adversely affected by the presence of oral contrast, metal implants and the poor image quality afforded by low dose CT images in general. Significant changes are necessary before the algorithm can be employed clinically in an unsupervised fashion. However, with further work performed, the algorithm could potentially prove useful for medical specialists staging lymphoma in the future.

Therapeutic response to a novel enzyme-targeting radiosensitization treatment (KORTUC II) for residual lesions in patients with stage IV primary breast cancer, following induction chemotherapy with epirubicin and cyclophosphamide or taxane.

Linac-based radiotherapy has a negligible effect on the majority of advanced neoplasms. Therefore, a novel radiosensitization treatment Kochi Oxydol Radiation Therapy for Unresectable Carcinomas II (KORTUC II), which utilizes hydrogen peroxide and sodium hyaluronate was developed. The effectiveness of KORTUC II for the treatment of chemotherapy-resistant supraclavicular lymph node metastases and recurrent breast cancers has previously been demonstrated. The present study evaluated the safety and efficacy of KORTUC II in patients with stage IV primary breast cancer. Seven patients (age range, 36–65 years) were enrolled. All patients received induction chemotherapy prior to KORTUC II treatment and underwent positron emission tomography-computed tomography (PET-CT) examinations prior to and 2–7 months following KORTUC II treatment, and every six months thereafter where possible. The radiotherapy regimen (x-ray irradiation) was 2.75 gray (Gy)/fraction, 5 fractions/week for 16–18 fractions with a total radiation dose of 44–49.5 Gy. Administration of the KORTUC II agent (3–6 ml: 3 ml for a lesion <3 cm in diameter and 6 ml for a lesion ≥3 cm) was initiated from the sixth radiotherapy fraction, and was conducted twice a week under ultrasonographic guidance. The therapeutic effects were evaluated by PET-CT examinations prior to and following KORTUC II treatment. Of the seven lesions from the seven patients, five exhibited complete responses, two exhibited partial responses and none exhibited stable disease or progressive disease. The overall survival rate was determined to be 100% at 1 and 86% at 2 years post-treatment. The mean duration of follow-up by December 2014 was 51 months. The results of the PET-CT studies indicated that KORTUC II treatment demonstrated marked therapeutic effects with satisfactory treatment outcomes and acceptable adverse effects.

Building and Querying RDF/OWL Database of Semantically Annotated Nuclear Medicine Images.

As the use of positron emission tomography-computed tomography (PET-CT) has increased rapidly, there is a need to retrieve relevant medical images that can assist image interpretation. However, the images themselves lack the explicit information needed for query. We constructed a semantically structured database of nuclear medicine images using the Annotation and Image Markup (AIM) format and evaluated the ability the AIM annotations to improve image search. We created AIM annotation templates specific to the nuclear medicine domain and used them to annotate 100 nuclear medicine PET-CT studies in AIM format using controlled vocabulary. We evaluated image retrieval from 20 specific clinical queries. As the gold standard, two nuclear medicine physicians manually retrieved the relevant images from the image database using free text search of radiology reports for the same queries. We compared query results with the manually retrieved results obtained by the physicians. The query performance indicated a 98% recall for simple queries and a 89% recall for complex queries. In total, the queries provided 95% (75 of 79 images) recall, 100% precision, and an F1 score of 0.97 for the 20 clinical queries. Three of the four images missed by the queries required reasoning for successful retrieval. Nuclear medicine images augmented using semantic annotations in AIM enabled high recall and precision for simple queries, helping physicians to retrieve the relevant images. Further study using a larger data set and the implementation of an inference engine may improve query results for more complex queries.

Evaluating PET‐CT in the detection and management of recurrent cervical cancer: systematic reviews of diagnostic accuracy and subjective elicitation

Positron emission tomography-computed tomography (PET-CT) is recommended to triage women for exenterative surgery and surveillance after treatment for advanced cervical cancer. To evaluate diagnostic accuracy of additional whole body PET-CT compared with CT/magnetic resonance imaging (MRI) alone in women with suspected recurrent/persistent cervical cancer and in asymptomatic women as surveillance. Systematic reviews. Subjective elicitation to supplement diagnostic information. Searches of electronic databases were performed to June 2013. Studies in women with suspected recurrent/persistent cervical cancer and in asymptomatic women undergoing follow up with sufficient numeric data were included. We calculated sensitivity, specificity and corresponding 95% confidence intervals. Meta-analyses employed a bivariate model that included a random-effects term for between-study variations (CT studies) and univariate random effects meta-analyses (PET-CT studies) for sensitivity and specificity separately. Prevalence of recurrence and the accuracy of imaging elicited using the allocation of points technique. Coherence of elicited subjective probabilities with estimates in the literature examined. We identified 15 relevant studies; none directly compared additional PET-CT with MRI or CT separately. Most CT and MRI studies used older protocols and the majority did not distinguish between asymptomatic and symptomatic women. Meta-analysis of nine PET-CT studies in mostly symptomatic women showed sensitivity of 94.8 (95% CI 91.2-96.9), and specificity of 86.9% (95% CI 82.2-90.5). The summary estimate of the sensitivity of CT for detection of recurrence was 89.64% (95% CI 81.59-94.41) and specificity was 76% (95% CI 43.68-92.82). Meta-analysis for MRI test accuracy studies was not possible because of clinical heterogeneity. The sensitivity and specificity of MRI in pelvic recurrence varied between 82 and 100% and between 78 and 100%, respectively. Formal statistical comparisons of the accuracy of index tests were not possible. Subjective elicitation provided estimates comparable to the literature. Subjective estimates of the increase in accuracy from the addition of PET-CT were less than elicited increases required to justify the use in PET-CT for surveillance. Evidence to support additional PET-CT is scarce, of average quality and does not distinguish between application for surveillance and diagnosis. Guidelines recommending PET-CT in recurrent cervical cancer need to be reconsidered in the light of the existing evidence base.

To operate or to radiate: the added value of the maximal standardized uptake value in PET–FDG in cervical cancer patients

Cervical cancer is one of the leading causes of death among women with gynecological malignancies. In early stages of the disease (IB-IIA), surgical treatment alone is usually the treatment of choice. However, some high-risk patients are referred for postoperative chemo-radiotherapy, leading to increased morbidity. Maximal Standardized Uptake Value (SUVmax) is a positron emission tomography-computed tomography (PET-CT)-derived semiquantitative measurement of fluorodeoxyglucose (FDG) uptake in a defined lesion and may reflect tumor aggressiveness. The purpose of this study was to determine whether preoperative high SUVmax values can be used for the selection of initial therapy, thus reducing the side effects resulting from bimodal treatment. PET-CT studies of 46 cervical cancer patients who underwent surgery were reviewed, and SUVmax data were collected. Statistical analyses were performed to determine the relationships between SUVmax values and clinical parameters, modalities of treatment, and outcomes. SUVmax was found to correlate with depth of tumor invasion (r = 0.46, p < 0.003). A statistically significant correlation was also found between SUVmax and histological grade, with the mean and variance of SUVmax significantly lower for grade one, as compared to grades two and three (mean 1.10, 11.06, and 8.88; variance 3.57, 45.60, and 29.79, respectively; p < 0.0001 and p = 0.076). A possible SUVmax cutoff value of 10.08 was identified as a potential indicator of increased risk for receiving bimodal treatment, with a sensitivity of 61.5 % and a specificity of 75.8 %. SUVmax can be used for differentiating early-stage cervical cancer patients who will need postoperative adjuvant treatment and therefore can serve as an additional modality to reduce the need for bimodal therapy in these patients.

The role of magnetic resonance imaging and positron emission tomography-computed tomography combined in differentiating benign from malignant lesions contributing to vertebral compression fractures

Background:Obtaining tissue confirmation of the underlying pathology is the gold standard for establishing the etiology of nontraumatic vertebral compression fractures. However, newer investigative modalities such as the magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) combined potentially offer the ability to distinguish between benign and malignant lesions, thereby circumventing the need for invasive tissue diagnostic/biopsy procedures.Methods:Twenty-four patients with nontraumatic, spontaneous vertebral compression fractures were prospectively studied. After clinical evaluation, all patients underwent MRI (with/without contrast) focusing on the spinal lesion, followed by whole-body PET-CT. This was followed by fine needle aspiration cytology (FNAC) of the lesion to confirm the diagnosis. The sensitivity and specificity of MRI and PET-CT studies were calculated for benign vs. malignant lesions.Results:The sensitivity/specificity of MRI for benign lesions were 78.57%/90%, while the sensitivity/specificity values of PET-CT for benign disease were 92.8%/90% respectively. Alternatively, the sensitivity/specificity of MRI for malignant lesions were 90%/78.57%, while the sensitivity/specificity of PET-CT for malignant disease were 90%/92.8%, respectively. Furthermore, the sensitivity for diagnosing malignant lesions utilizing both studies together was 100%, but the algorithm was not specific. Additionally, the specificity for MRI and PET-CT combined was 100% for benign lesions. PET-CT also helped in monitoring responses to empirical antitubercular treatment (ATT) therapy. Of interest, FNAC was inconclusive in four cases in which PET-CT findings helped further in either obtaining a tissue diagnosis from another location or institution of empirical therapy in suspected cases of tuberculosis.Conclusions:The specificity for MRI and PET-CT combined was 100% for benign lesions. Unfortunately, the specificity for MRI and PET-CT combined was not 100% for malignant vertebral lesions, though it was sensitive. The PET-CT scan was an extremely useful tool when FNAC from the affected site proved inconclusive. It gave additional information regarding the overall extent of disease, while identifying other locations amenable to FNAC. Furthermore, in countries where tuberculosis is endemic, the empirical response to ATT therapy could be monitored utilizing PET-CT.

Primary gastric lymphoma: utility of 18F-fluorodeoxyglucose positron emission tomography-computed tomography for detecting relapse after treatment

The purpose of this study was to evaluate the role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) in detecting relapse in patients with primary gastric lymphoma (PGL) post-treatment. Data of 39 previously treated patients with PGL (age: 50.3 ± 13.8 years; male: 24) who underwent 71 18F-FDG PET-CT studies for suspected relapse (n = 53) or routine follow-up (n = 18) were retrospectively evaluated. PET-CT images were evaluated both qualitatively and quantitatively (standardized uptake value [SUVmax]). A combination of clinical/imaging follow-up, endoscopy and/or histopathology was taken as the reference standard. The per patient based sensitivity of PET-CT was 96%, specificity 91% and accuracy 93%. The lymph node was the commonest site of relapse on PET-CT. Mean lesion SUVmax was 5.9 ± 3.1 (2.3–13.6). Accuracy was similar in suspected relapse and routine follow-up groups (90.5% vs. 100%; p = 0.409). Based on the data, 18F-FDG PET-CT appears to be highly accurate for the detection of relapse in patients with PGL post-treatment.

Morphological-metabolic evaluation of the urachal mucinous adenocarcinoma by positron emission tomography-computed tomography (PET-CT)

The urachal mucinous adenocarcinoma is a rare malignant neoplasm located between the bladder and the umbilicus. It is usually found in an advanced stage at the moment of diagnosis. We have analyzed a clinical case in which the PET-CT study provided valuable morphological and metabolic information for diagnosis and staging.

Inverse association between brown adipose tissue activation and white adipose tissue accumulation in successfully treated pediatric malignancy

Although the accumulation of white adipose tissue (WAT) is a risk factor for disease, brown adipose tissue (BAT) has been suggested to have a protective role against obesity. We studied whether changes in BAT were related to changes in the amounts of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in children treated for malignancy. We examined the effect of BAT activity on weight, SAT, and VAT in 32 pediatric patients with cancer whose positron emission tomography-computed tomography (PET-CT) scans at diagnosis showed no BAT activity. Changes in weight, SAT, and VAT from diagnosis to remission for children with metabolically active BAT at disease-free follow-up (BAT+) were compared with those in children without visualized BAT when free of disease (BAT-). Follow-up PET-CT studies (4.7 ± 2.4 mo later) after successful treatment of the cancer showed BAT+ in 19 patients but no active BAT (BAT-) in 13 patients. BAT+ patients, in comparison with BAT- patients, gained significantly less weight (3.3 ± 6.6% compared with 11.0 ± 11.6%; P = 0.02) and had significantly less SAT (18.2 ± 26.5% compared with 67.4 ± 71.7%; P = 0.01) and VAT (22.6 ± 33.5% compared with 131.6 ± 171.8%; P = 0.01) during treatment. Multiple regression analysis indicated that the inverse relations between BAT activation and measures of weight, SAT, and VAT persisted even after age, glucocorticoid treatment, and the season when the PET-CT scans were obtained were accounted for. The activation of BAT in pediatric patients undergoing treatment of malignancy is associated with significantly less adipose accumulation. This trial was registered at clinicaltrials.gov as NCT01517581.

Spreadsheet program for estimating recovery coefficient to get partial volume corrected standardized uptake value in clinical positron emission tomography-computed tomography studies

Purpose:To develop a spreadsheet program for estimation of recovery coefficient (RC) to get partial volume corrected (PVC) standardized uptake value (SUV) in clinical positron emission tomography-computed tomography (PET-CT) studies.Materials and Methods:For formulation of this program we used data from a phantom study conducted at our center in which a phantom with a sphere assembly (seven spheres-different diameters) was filled with 18F-Fluorodeoxyglucose solution to get a sphere/background ratio of 8:1, 10:1 and 12:1. PET-CT images were acquired. RC was then calculated from processed PET-CT images. We plotted graph of RC versus lesion-size at different sphere/background ratio using MS Excel function. There was logarithmic increase in RC with increase in lesion size. We fitted the data with a logarithmic equation and found optimum fit (least-square fit). We then validated this program with clinical data using 42 lung nodules in five patients.Results:The program estimates the value of RC and object to background ratio in PET-CT for the input lesion-size and displays graph with trendline. When the user enters SUV and background activity measured in clinical PET-CT, it provides the value of RC and PVC SUV. It also validates the data entry and displays appropriate message. It is consistent, reproducible, accurate and provides output for wide range of lesion-sizes (71% of lesions evaluated); however, program does not give output for lesion-size < 9 mm.Conclusion:The present spreadsheet program is a useful and easy tool for calculating PVC SUV of clinical PET-CT lesions.

Coexisting iodine avid and iodine nonconcentrating lesions with multiple distant soft tissue metastasis in papillary thyroid cancer

Distant soft tissue metastasis and the simultaneous presence of iodine concentrating and nonconcentrating lesions in papillary thyroid cancer are extremely rare. The concerned patient, a histopathologically proven case of papillary thyroid cancer with nodal metastases treated with total thyroidectomy, bilateral cervical nodal dissection, and radioablation, subsequently developed lung, muscle, and liver metastasis. Triggered by increased thyroglobulin, the iodine-131 whole body scan and 200 mci iodine-131 post-therapy scan showed a left gluteus maximus lesion and a liver lesion. Fludeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) scan intended to find additional lesions revealed iodine and FDG nonconcentrating bilateral pulmonary nodules and a single FDG avid hepatic and two muscle metastases. Although FDG concentration in metastatic pulmonary nodules is generally low, the CT characteristics were classical for metastatic lesion. A follow-up FDG PET-CT study six months after 200 mci iodine-131 radioablation showed treatment response in muscle and liver lesions but not lungs.

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.

Pediatric lymphoma: metabolic tumor burden as a quantitative index for treatment response evaluation

Metabolic tumor burden (MTB) incorporates the advantages of the existing indices: the metabolic volume of the lesion calculated by size-dependent thresholding on positron emission tomography-computed tomography (PET-CT) along with its aggressiveness as determined by standardized uptake value (SUV). This study was conducted to investigate whether MTB can be used as an objective index for monitoring therapy response in pediatric lymphoma. Forty-two pediatric patients (35 male and 7 female) with histologically proven lymphomas (26 Hodgkin's and 16 non-Hodgkin's) were evaluated. MTB was assessed in baseline, early interim (after 2 cycles) and post-therapy PET-CT studies using RT_Image software. Size-dependent thresholding based on a phantom study conducted at our institute was used for the calculation of metabolic tumor volume (MTV). MTB was given as the product of MTV and the SUVmean. Summation of MTB from all lesions gave the whole body MTB. Baseline, early interim and post-therapy SUVmax and whole body MTB of the partial and complete response group were compared. Of 42 patients, 37 had complete response and 5 had partial response at the end of therapy based on clinical, CECT and bone marrow biopsy findings. SUVmax showed an overall reduction of 87.4% while MTB showed a reduction of 96.4% between baseline and early interim PET-CT scan. Similarly, SUVmax showed an overall reduction of 95.2% while MTB showed a reduction of 99.6% between baseline and post-therapy scan. There was significant difference between MTB of partial response and complete response group at baseline and early interim PET-CT (p 0.031 and 0.012, respectively). No such significant difference was found for SUVmax. Whole body MTB appears to be useful quantitative parameter for the assessment of treatment response using PET-CT in pediatric lymphoma patients.

Cortical-limbic regions modulate depression and anxiety factors in functional dyspepsia: a PET-CT study

To observe some specific brain areas or cerebral functional network participating in the modulation of depression and anxiety factors in functional dyspepsia (FD) patients by detecting cerebral glucose metabolism (CGM) in fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography-computed tomography (PET-CT) scans. Eight FD patients with depression and anxiety (DA-FD group) and eight FD patients without depression and anxiety (non-DA-FD group) were recruited and evaluated by the Nepean Dyspepsia Index (NDI) and Dyspepsia Symptom Scores (DSS). Cerebral (18)F-FDG PET-CT scans were performed on the DA-FD group and non-DA-FD group, respectively. The differences in CGM between the two groups were analyzed with SPM2. Extensive changes in the CGM signals were observed in the cerebral cortex and limbic system of FD patients with depression and anxiety. Compared to non-DA-FD patients, DA-FD patients showed a higher glucose metabolism in the right postcentral gyrus (BA 1 and 5), inferior frontal gyrus (BA 45), superior temporal gyrus (BA 22), middle temporal gyrus (BA 22), inferior parietal lobule (BA 40), lingual gyrus (BA 18) and the left middle occipital gyrus (BA 37), as well as the limbic system including the left thalamus, lateral globus pallidus, parahippocampal gyrus (BA 35), right insular cortex (BA 13) and parahippocampal gyrus (BA 18); a lower glucose metabolism was presented in the left middle cingulated gyrus (BA 24), the right superior frontal gyrus (BA 6), the medial frontal gyrus (BA 6) and middle temporal gyrus (BA 21). An extensive cortical-limbic brain network might modulate the procession of FD patients with depression and anxiety factors.

Impact of PET‐CT on Primary Staging and Response Control on Multimodal Treatment of Esophageal Cancer

The predictive value of positron emission tomography-computed tomography (PET-CT) in primary staging and response control in patients with esophageal carcinoma (EC) is under discussion. In the present study initial staging and metabolic response of PET-CT was correlated with tumor regression and survival in patients with multimodal treatment of EC. The authors conducted a retrospective analysis on a prospective database for 83 patients with EC (42 squamous cell, 39 adenocarcinoma, 2 anaplastic carcinoma) undergoing PET-CT for primary staging. Twenty-four of the patients underwent primary esophagectomy, 9 had palliative treatment, and 50 neoadjuvant radiochemotherapy (cisplatin, 5-fluorouracil; 50.4 Gy). The PET-CT study was repeated 6 weeks after induction of chemotherapy and compared with endoscopic ultrasound (EUS). For response control, the metabolic response (tumor standardized uptake value [SUV] reduction) was correlated with histopathologic (ypT0-4) and histomorphologic response (tumor regression) and survival. At primary staging 81 of 83 EC (97.5%) showed an increased SUV uptake correlating with the EUS tumor stage. Suspicious lymph nodes were detected in 51 (61.4%) patients by PET-CT and 66 (79.5%) were detected by EUS. Fifteen patients had additional findings on PET-CT examination leading to a change in therapy in 9 patients (10.3%). Of 50 patients receiving a second PET-CT study, a SUV reduction >50% correlated with major histomorphologic response (tumor regression grade 4, <10% vital tumor cells) and histopathologic response (ypT0 ypN0). Furthermore, these patients showed a significantly increased survival (33.1 ± 3.5 months) compared to non-responders (21.7 ± 3.3 months; p = 0.02) and patients after primary surgery (29 ± 3.2 months; p = 0.05). The present study shows that PET-CT is a valuable tool for primary staging and response control in multimodal treatment of patients with EC.