FDG PET-CT Scan Research Articles

0319: Long standing fever in patients with cardiovascular prostheses: role of 18-fluoro deoxyglucose positron computer tomography combined with computerized tomography in diagnosis and management

the diagnosis of infected protheses in patients with long standing fever is difficult, challenging and has major impact on the management. Since 18-Fluo Desoxyglucose positron emission tomography performed together with computerized tomography (FDG PET-CT) has a role in the diagnosis and localization of infection; we evaluated its value in the diagnosis of infected prostheses, correlating its results with medical workup, echo-cardiogram and dedicated CT. Patients: Fourteen patients (pts) with cardiovascular prostheses (seven with a pacemaker, four with vascular grafts, two with pulmonary stent and one with mitral valve prosthesis were hospitalized for prolonged fever. All pts received antibiotics and underwent repeated medical workup. Eight of the 14 pts had a proven bacteriemia. Transthoracic and transoesophagial echocardiogram was performed as well as CT, for most of them. FDG PET-CT was performed in all of them, following injection of 370 MBq of F-18 FDG. All patients were normoglycemic at the time of injection. Results of the FDG PET-CT were compared with other diagnostic modalities and clinical follow up. In the 7 pts with pacemaker, FDG PET-CT was positive in 4, echo in 2/4. IN 3/4 the device was removed. A new pacemaker was implanted for two patients after few weeks. FEG PET-CT was negative in 3/7 pts with 1 positive, 1 negative and 1 intermediate results. All patients with vascular graft had positive FDG PET-CT scan and only one had a positive echocardiogram. This patient had a surgical proven abscess. Two pts with pulmonary stent had a positive FDG PET-CT scan and 1 positive echo. In this patient the stent extracted was infected. FDG PET-CT and echo was negative in the patient with mitral prosthesis.Conventional CT was positive in only 1 patient. Twelve pts return to normal including all the patients after prostheses extraction except one who died during graft replacement. FDG PET -CT is a useful tool for the diagnosis of infected cardiovascular prosthesis and is more accurate than stand alone CT. Correlation of the clinical, echo and FDG PET CT findings is crucial for the therapeutic decision.

P-069 Can PET CT Scans Be Used as a Predictor of Response to Treatment With Anti-TNF Agents in Patients With Crohn’s Disease?

Up to a third of patients with Crohn’s disease treated with Anti-TNF therapies are primary non-responders. Primary nonresponse may, in part, be due to stricturing disease with scarring rather than inflammation as the underlying pathology. Currently, the only way to identify primary nonresponders is to observe a lack of clinical and endoscopic response after repeated exposure to the medication. FDG-PET CT scans are a reliable tool to detect inflammation in the small bowel and may identify patients who are more likely to obtain benefit with Anti-TNF therapy. Our AIM was to determine whether low dose FDG-PET CT scan performed prior to first Anti-TNF exposure could identify patients likely to be responders at 12 weeks after Anti-TNF administration. Consecutive patients with small bowel Crohn’s disease who require therapy with Anti-TNF agents were recruited for the study. Information on disease information and disease activity were collected at the screening visit. An FDG-PET was performed and the maximum standardized uptake value (SUVmax) was calculated for each patient. The treating physician was blinded to the results. Patients were initiated on Anti-TNF therapy and re-evaluated for clinical response at week 12. Five consecutive patients with known small bowel Crohn’s disease with a clinical indication for treatment with anti-TNF therapy were recruited for the study (Table 1). All patients underwent FDG-PET CT scan and were exposed to infliximab. Three of 5 patients completed infliximab loading (1 lost to follow up, 1 required surgery). Two of 5 patients were identified as primary nonresponders at 12 weeks, but they were not associated with low SUVmax (Table 2). The SUVmax ranged from 5.2 to 13.4 (Table 1–2). There was not a statistically significant association between response to AntiTNF and treatment on SUVmax pretreatment. In this pilot study of patients with small bowel Crohn’s disease, FDG- PET CT scans did identify variable degrees of inflammation in the small bowel. Alternatives to SUVmax may be necessary to identify patients with small bowel inflammation that may be responsive to Anti-TNF therapy.

FDG PET-CT Finding in Bilateral Renal and Bone Involvement of Diffuse Large B-Cell Lymphoma.

Thirty-six year old male patient with pathological fracture of the left tibia underwent intramedullary and soft tissue curettage. The histopathological examination revealed diffuse large B cell lymphoma. The patient underwent F18-FDG PET-CT scanning for initial staging. FDG PET-CT scan revealed hypermetabolic lesions at the left tibia and in bilateral kidneys. After the systemic chemotherapy and local radiotherapy to the tibia, repeated FDG PET/CT scan showed improvement of the previous hypermetabolic lesions, suggesting good response to therapy. Bone and renal involvement is an uncommon variant of diffuse large B-cell lymphoma and FDG PET-CT is an useful whole body imaging modality in these cases.

Potential role of F18 FDG PET-CT as an imaging biomarker for the noninvasive evaluation in uncomplicated skeletal tuberculosis: a prospective clinical observational study.

This is a prospective non-randomized observation study done on 33 patients with uncomplicated spinal tuberculosis to observe the imaging characteristics on sequential F-18 FDG PET CT scans. 33 consecutive patients with pathologically proven spinal tuberculosis underwent a baseline contrast-enhanced whole body FDG PET scan before initiation of antitubercular therapy, 6 and 12 months and at 18 months or the end of antitubercular therapy. The baseline peak SUVmax of lesions in our 33 cases had values ranging from 5.9 to 30.3 (mean 14.8). 63.6 % patients had clinically occult non-contiguous multifocal skeletal involvement at the time of the baseline whole body PET CT scanning. The mean change in SUVmax at various time points was highly significant (p value < 0.001). SUVmax can be taken as a reliable marker for serial quantification of metabolic activity in spinal tuberculosis. This may translate into a potential role for FDG as an imaging biomarker for noninvasive response evaluation in skeletal tuberculosis.

AB0597 FDG PET-CT versus Temporal Artery Biopsy in Patients Presenting with Gca/Pmr: A Retrospective Cross-Sectional Study

BackgroundGiant Cell Arteritis (GCA) is a large vessel vasculitis, which can occur concomitant with Polymyalgia Rheumatica (PMR). Both diseases may also be seen as isolated disease entities. The two conditions...

Thyroid incidentalomas discovered on positron emission tomography CT scanning – Malignancy rate and significance of standardised uptake values

AimsIncreasing use of 18F-Fluorodeoxy glucose (FDG) Positron Emission Tomography Computed Tomography (PET CT) has resulted in an increased frequency of incidentally discovered areas of focally increased FDG uptake within the thyroid gland – thyroid incidentalomas. We aimed to compare radiological characteristics of thyroid incidentalomas with cytology, histology and ultrasound findings. Materials and methodsWe examined all FDG PET CT scan reports for all patients undergoing this investigation over a 6 year period in a single tertiary cancer centre. All PET CT scans followed an agreed proforma allowing reports mentioning “thyroid” to be identified. Reports commenting on a positive finding within the thyroid gland were investigated further manually. Incidental mentions of thyroid with no underlying abnormality were discounted from analysis. ResultsIn the study period, 7221 patients underwent FDG PET CT scanning in our unit. Within this group 75 (1%) showed diffuse FDG uptake and 81 (1.1%) showed focal uptake (thyroid incidentalomas). Only 30 patients (37%) with incidentalomas had further investigation and malignancy rate was 23% (7/30). Median Standardised Uptake Values (SUV) in malignant lesions was 9.9 (range 3.5–17.8) whilst in benign lesions and diffuse lesions it was 5.4 (2.8–32) and 4.2 (2.1–25.6) respectively (p = 0.0013, Kruskal Wallis). ConclusionThere remains a need to develop a standardised approach to the investigation and management of thyroid incidentalomas discovered on FDG PET CT scanning. Up to 1 in 4 of these patients will harbour thyroid malignancy.

False Positive FDG PET/CT of Recurrent Testicular Tumour Due to Orchitis

A 47-year-old male with a history of right sided orchidectomy for stage 1 seminoma 6 months previously, was referred for a FDG PET-CT scan for restaging of testicular cancer having experiencing left testicular discomfort. Abnormally increased glyoclytic metabolism of the left testis and the inferior scrotal sac was demonstrated on the initial FDG PET-CT study. Subsequent ultrasound showed subtle heterogeneous echotexture with mild hypervascularity and no focal lesion was identified. The patient was subsequently treated with antibiotics for a presumed diagnosis of orchitis. A progress FDG PET-CT study 2 months later confirmed the complete resolution of the increased glycolytic metabolism in the left testis and the inferior scrotal sac. Conflict of interest:None declared.

Utility of FDG-PET-CT scanning in assessing the extent of disease activity and response to treatment in sarcoidosis.

Background:Radionuclide imaging modalities have increasingly been evaluated in the assessment of organ involvement in sarcoidosis. Fluoro-deoxyglucose positron emission tomography–computed tomography (FDG–PET–CT) scanning has received increasing attention in the recent years. The aim of our study was to evaluate the utility of FDG–PET–CT in determining the extent of organ involvement and disease activity in patients of sarcoidosis and to assess its utility in the evaluation of response to therapy. The secondary objective was to compare the agreement between clinical, radiological (HRCT) and metabolic indices (FDG–PET–CT) of disease activity.Materials and Methods:This was a prospective observational study conducted between March 2007 and December 2008 at a tertiary care referral center in north India. Twenty-five symptomatic and histopathologically proven cases of sarcoidosis underwent FDG–PET–CT scanning at baseline and a follow-up scan in 21 patients at 6-9 months post-treatment with glucocorticoids.Results:FDG–PET–CT scan detected metabolic disease activity in 24 of the 25 patients with clinically active sarcoidosis. It also demonstrated many clinically inapparent sites of disease activity. Complete or partial metabolic response was seen in 17 of the 21 patients in whom a follow-up scan was available. Substantial degree of agreement was found between the metabolic response and the radiological response, whereas moderate agreement was found between clinical and metabolic responses.Conclusions:FDG–PET–CT scanning is a useful imaging modality to assess disease activity, extent of disease involvement and response to treatment in clinically active sarcoidosis. There is substantial agreement between the HRCT and metabolic parameters of disease activity. Further, large sample size studies are proposed in order to identify the subset of patients who are likely to benefit the most from this sensitive modality of imaging, especially in developing countries where the cost of the procedure is an important concern.

Survival outcomes for patients with equivocal 18FDG-PET CT scan for extrahepatic disease prior to liver resection for metastatic colorectal cancer.

1581 Background: Patients considered for liver resection (LR) for hepatic metastases from metastatic colorectal cancer (mCRC) have an 18FDG-PET CT scan (PET) to exclude extrahepatic disease (EHD). The prognostic significance of an equivocal PET on overall survival (OS) for patients who proceed to LR is not entirely clear. The aim of the study is to compare OS for patients with equivocal PET prior to LR to those with a PET negative for EHD. Methods: The South Australian Metastatic Colorectal Cancer Registry collects data for mCRC patients diagnosed after February 1, 2006. Patients were included if they had LR and a PET prior to LR. PETs were coded as no EHD and possible EHD. The Cox proportional hazard model was applied to analyse the outcome of patients with an equivocal PET for EHD on OS, adjusting for possible confounders. Results: Of the 2,480 patients on the registry, 273 had had LR. Of these, 183 (67.0%) had a PET prior to LR, with 137 having no EHD and 46 having possible EHD. The no EHD and possible EHD groups were well balanced for patient, tumour and treatment characteristics – mean age: 66.7 yrs-vs-68.4 yrs, male gender: 61.3%-vs-63.0%, KRAS wildtype: 11.0%-vs-16.3%, stage IV disease at initial diagnosis: 49.6%-vs-54.3%, colonic primary: 74.4%-vs-65.2%, one LR: 82.5%-vs-89.1%, one line of chemotherapy: 52.4%-vs-48.6% and well-moderate tumour differentiation: 85.7%-vs-86.4%. The median follow-up was 32.9 months for no EHD and 33.6 months for possible EHD (P-value = 0.84). The OS for no EHD compared with possible EHD at 1-year was 98.5%-vs-93.5%, at 2-years was 87.6%-vs-88.0%, and at 5-years was 61.5%-vs-59.4%. The unadjusted hazard ratio for OS was 1.22 (95% CI 0.64–2.34, P-value = 0.54) for possible EHD. On adjustment for age, gender, stage at diagnosis, primary site, number of LRs, lines of chemotherapy and tumour differentiation, the hazard ratio remained non-significant; however lower (HR=0.76 (95% CI 0.37–1.59, P-value = 0.47)), for possible EHD. Conclusions: A PET was only performed in 67.0% of patients who had LR for mCRC. There was no difference in OS between patients with no EHD and possible EHD on PET who proceed to LR.

Pharmacodynamic effects of regorafenib in metastatic colorectal carcinoma (mCRC).

e14507 Background: Regorafenib, an oral multikinase inhibitor of VEGFR2/3, PDGFRb, KIT, FGFR, RET, RAF and TIE2, is efficacious in refractory mCRC but its mechanism of action is unclear and predictive biomarkers are lacking. Methods: We assessed tumor and circulatory biomarkers in a phase 2 study of regorafenib in refractory mCRC patients. Regorafenib was administered orally at 160mg/d for 3 out of 4 weeks. Post cycle 2 response was assessed by RECIST 1.1. Subjects were scheduled for FDG PET-CT scans (pre + D15) and paired core needle tumor biopsies for IHC analysis (pre + D21) in cycle 1. Archival tumor mutations were evaluated using Sequenom MassARRAY OncoCarta Panel V1.0 assay. Results: 35 patients were treated; 49% received &gt; 4 prior therapies and 43% had prior bevacizumab. Median PFS was 3.45 mths (95% CI: 3.40-3.49), ORR was 3% and disease control rate [DCR] (PR + SD at 8 wks) was 57%. Early PET responses (EORTC criteria) were seen in 49%, but did not predict for DCR (p=1.0). Fatigue, hand foot skin reaction (HFSR), voice change and diarrhea occurred in &gt; 30% of subjects. Grade 3-5 toxicities occurred in 46%, the commonest being HFSR and rash (17% each). Median relative dose intensity was 92%; 43% required &gt; 1 dose reduction, 60% required &gt; 1 dose interruption. KRAS (29%), BRAF (9%), EGFR (9%), NRAS (6%) KIT (3%), PIK3CA (3%), PDGFRA (3%) and CDK (3%) mutations were detected in archival tumors. None predicted for ORR or DCR; PFS was identical in KRAS mutant vs wt patients (3.45 mths, p=0.39) and similar in BRAF mutant vs wt patients (3.48 vs 3.45 mths, p=0.10). The patient with the longest PFS (12.6 mths) had a BRAF mutation. Amongst the 10 paired tumor samples available, IHC markers upregulated in &gt;50% cases were pMEK, pERK, pJun and pJNK, whilst those downregulated/ unchanged in &gt;50% were pKIT, pVEGFR2, CD31 [vascular endothelial cells (ECs)] and podoplanin (lymphatic ECs). The greatest change was observed in podoplanin expression, corresponding to a 60% reduction in lymphatic vessel density. Conclusions: FDG-PET responses in cycle 1 did not predict for regorafenib clinical benefit in mCRC patients. Targeting lymphatic/vascular ECs in the tumor microenvironment may be a more significant antitumor mechanism of regorafenib than MAP kinase pathway inhibition. Clinical trial information: NCT01189903.

Utility of FDG-PETCT and magnetic resonance spectroscopy in differentiating between cerebral lymphoma and non-malignant CNS lesions in HIV-infected patients

Background and purposeIn HIV infected patients, MRI cannot reliably differentiate between central nervous system (CNS) lymphoma and non-malignant CNS lesions, particularly cerebral toxoplasmosis (CTOX). This study prospectively investigates the utility of FDG PET-CT and magnetic resonance spectroscopy (MRS) in discriminating CNS lymphoma from non-malignant CNS lesions in HIV infected patients, and assesses the ability of FDG PET-CT to guide the use of early brain biopsy. Methods10 HIV patients with neurological symptoms and contrast enhancing lesions on MRI were commenced on anti-toxoplasmosis therapy before undergoing FDG PET-CT and MRS. Brain biopsies were sought in those with FDG PET-CT suggestive of CNS lymphoma, and in those with a negative FDG PET-CT scan who failed to respond to therapy. Final diagnosis was based on histology or treatment response. ResultsTwo patients were confirmed to have CNS lymphoma and FDG PET-CT was consistent with this diagnosis in both. Six patients had cerebral toxoplasmosis in all of whom FDG PET-CT was consistent with non-malignant disease. One patient had progressive multifocal leukoencephalopathy (PML), FDG PET-CT was equivocal. One patient had a haemorrhagic brain metastasis and FDG PET-CT wrongly suggested non-malignant disease. MRS was performed successfully in eight subjects: three results were suggestive of CNS lymphoma (one true positive, two false positive), four suggested CTOX (two false negative, two true negative), one scan was equivocal. ConclusionFDG PET-CT correctly identified all cases of CNS lymphoma and CTOX, supporting its use in this situation. MRS was unhelpful in our cohort.

Sensitivity and specificity of FDG PET-CT scan in detecting lymph node metastasis in operable periampullary tumours in correlation with the final histopathology after curative surgery

18F-Fluorodeoxyglucose-positron emission tomography/computerised tomography (FDG-PET/CT) was investigated for evaluation of periampullary tumours and other gastrointestinal neoplasms. The aim of this study was to evaluate the utility of FDG-PET/CT for detection of lymph node metastasis in periampullary tumours by comparing the preoperative FDG-PET/CT scan finding with postoperative histopathology of lymph nodes. Study was done on 24 patients with diagnosis of periampullary carcinoma either proven or suspected on conventional radiology. Standard uptake value (SUV) were measured for lymph node areas with uptake in FDG-PET/CT and compared with histopathological lymph node status. For detection of lymph node metastasis, FDG-PET/CT with cutoff value SUV max ≥2.0 had a sensitivity of 71.4% and specificity of 77.8% and that for SUV max ≥2.5 and 2.8 were 57.1, 42.9 and 77.8, 77.8%, respectively. The sensitivity and specificity of FDG-PET/CT at each lymph node groups were 72 and 89% in peripancreatic area, 100 and 93% in hepatoduodenal area and 100 and 100% in aortocaval area at SUV max ≥2.0, respectively. At SUV max ≥2.5 the values were 57 and 89% in peripancreatic area, 100 and 93% in hepatoduodenal area and 100 and 93% in aortocaval area. FDG-PET-CT has a possible role in detection of lymph node metastasis in periampullary carcinomas and may be used as a guide for possible lymphadenectomy during surgery and for prognostic purpose.

Akinetic-rigid syndrome: An unusual presentation of hypoglycemic encephalopathy

Hypoglycemia is an emergency. If untreated, it can result persistent neuronal injury of the central nervous system. The neurologic manifestations of hypoglycemia ranges from headache, seizure, different neuropsychiatric symptoms to stupurous, coma and stroke like symptoms. Akinetic-rigid syndrome, a severe form of extra pyramidal symptom is rarely described with hypoglycemic brain damage. The magnetic resonance imaging (MRI) findings are variable and reversible which ranges from normal study to diffusion restriction and white matter hyper intensities involving both cortical and sub cortical white matter as well as grey matter. This case illustrates a 32-year-old male with history of intermittent hypoglycemia of unknown cause for three years duration presenting with prolonged akinetic mutism and extra pyramidal symptoms. His brain MRI revealed bilateral symmetrical white matter hyper intensities involving corona radiata , internal capsule and middle cerebellar peduncles with 18F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET CT) scan of brain showed hypometabolism involving bilateral parietal lobes, basal ganglia, thalamus and cerebellum, which reversed with correction of blood sugar within next four weeks. Hypoglycemic encephalopathy (HE) may develop reversible extra pyramidal syndromes. Clinico-neuro imaging correlation is not always possible. Besides routine evaluation for hypoglycemia, neuroimaging such as MRI of brain and 18F- FDG PET CT scan may contribute to recognize the disease process and its outcome.

18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging of extra-medullary plasmacytoma of the ovary

Extrameduallary plasmacytoma of ovary is extremely rare. We report a case of involvement of ovary in a treated case of plasmacytoma of 2nd part of duodenum, which was initially thought to be physiological luteal activity. However, follow up whole body FDG PET-CT scan shows appearance of metabolically active soft tissue mass in left adnexal region which confirmed to be extra-medullary plasmacytoma of ovary on histopathology.

Prognostic value of metabolic volume measured by F-18 FDG PET-CT in patients with esophageal cancer.

The aim of this study was to evaluate the usefulness of the metabolic tumor volume (MTV) measured by F-18 Fluorodeoxyglucose positron emission tomography (FDG PET-CT) in predicting recurrence free survival (RFS) in patients with esophageal cancer. Forty-five patients with squamous cell carcinoma, who had undergone whole-body F-18 FDG PET-CT scans before surgical resection, were included in this study. All patients were treated with Ivor-Lewis esophagectomy. The MTV was quantified within the primary tumor using the 50% threshold of the maximum standardized uptake value (SUVmax ) of the FDG uptake areas. The cutoff value of MTV50 was determined through receiver-operating characteristic curve. The Kaplan Meier method was used to find out the relationship between RFS and MTV50 . Univariate analysis and multivariate proportional hazards regression analysis were applied to test the significance of volumetric parameter of F-18 FDG PET-CT and other conventional prognostic factors for the prediction of RFS. Overall median follow up period was 17.87 months (range: 1.07-63.27 months). The median survival between treatment completion and recurrence was 15.5 months (range: 1.37-72.43 months). Recurrence was found in eight patients. On univariate analysis, MTV50 (P = 0.0032), N stage (P = 0.0004), American Joint Committee on Cancer stage (P = 0.0101), tumor location (P = 0.0054) and adjuvant treatment (P = 0.0373) were significant predictors of RFS. Multivariate analysis showed that the independent prognostic factors were MTV50 (P = 0.0465), N stage (P = 0.0303) and tumor location (P = 0.0270). Volume based parameter of F-18 FDG PET-CT may have a role in providing prognostic information in esophageal cancer patients who received esophagectomy.

Unexpected Significantly Reduced FDG Uptake in the Cerebrum Compared Against Normal Liver Uptake in a Dying Patient

F-18 FDG PET-CT scanning plays an important role in the management of fever of unknown origin (FUO). Some elderly patients with FUO can be in their terminal stage of life. An elderly woman was referred for a PET-CT scan to find the etiology of FUO. The scan was inconclusive but showed significantly reduced FDG uptake in the brain and heart, despite normal physiological uptake in the liver and bowel. The patient deceased within the hour post scan. Contrary to common belief, we have shown that cerebral glucose metabolism via cerebral perfusion may be compromised before hepatic and bowel perfusion in a dying patient. Conflict of interest:None declared.

18-Fluoro-Deoxy-Glucose Positron Emission Tomography With Computed Tomography–Based Gross Tumor Volume Estimation and Validation With Magnetic Resonance Imaging for Locally Advanced Cervical Cancers

Anatomy and morphology-based imaging is routinely used for radiotherapy purpose to deliver precision treatment. There is an interest in using information from functional imaging for conformal radiation therapy planning. These functional imaging techniques need to be validated rigorously before their routine use. We attempted to evaluate and validate the use of 18-fluoro-deoxy-glucose positron emission tomography with computed tomography (¹⁸FDG PET-CT) on primary tumor of the cervical carcinoma, with an aim of arriving at a cutoff maximum standardized uptake value (SUVmax) at which the tumor volume correlates best with magnetic resonance imaging (MRI). This observational study was a part of an ethics committee-approved study evaluating pretreatment MRI and FDG PET-CT. Patients' biopsy-proven cervical carcinomas (stages IIB and IIIB) were included in this study and underwent pretreatment MRI and FDG PET-CT as per institutional protocol. Volumes of the disease at the cervix on the MR image were calculated. Volumes at the FDG PET-CT scan at different percentages of SUVmax were auto contoured. Volume at MRI was correlated with each different percentage cutoff of the SUVmax. Data of 74 patients were available for the study. The mean (SD) SUVmax of the primary tumor was 15.7 (7.0). The mean MRI volume correlates significantly (P < 0.001) with 30% and 35% of SUVmax values with good correlation according to the Pearson bivariate correlation (r = 0.79 each). The mean difference between MRI and PET volumes was least with 30% SUVmax. ¹⁸FDG PET-CT SUV-based primary tumor volume estimation at 30% to 35% of SUVmax values correlates significantly with the criterion standard MR volumes for primary cervical tumor with squamous histology in our population.

99mTc-DMSA (V) in Evaluation of Osteosarcoma: Comparative Studies with 18F-FDG PET/CT in Detection of Primary and Malignant Lesions

To evaluate the role of 99mTc-DMSA (V) and [18F]FDG PET-CT in management of patients with osteosarcoma, 22 patients were included in our study. All patients underwent both 99mTc-DMSA (V) and whole-body [18F]FDG PET-CT scans within an interval of 1 week. 555–740 MBq of 99mTc-DMSA (V) was injected i.v. the whole-body planar, SPECT images of primary site and chest were performed after 3-4 hours. [18F]FDG PET-CT images were obtained 60 minutes after i.v. injection of 370 MBq of F-18 FDG. Both FDG PET-CT (mean SUVmax = 7.1) and DMSA (V) scans showed abnormal uptake at primary site in all the 22 patients (100% sensitivity for both). Whole-body PET-CT detected metastasis in 11 pts (lung mets in 10 and lung + bone mets in 1 patient). Whole-body planar DMSA (V) and SPECT detected bone metastasis in one patient, lung mets in 7 patients and LN in 1 patient. HRCT of chest confirmed lung mets in 10 patients and inflammatory lesion in one patient. 7 patients positive for mets on DMSA (V) scan had higher uptake in lung lesions as compared to FDG uptake on PET-CT. Three patients who did not show any DMSA uptake had subcentimeter lung nodule. Resuts of both 99mTc-DMSA (V) (whole-body planar and SPECT imaging) and [18F]FDG PET-CT were comparable in evaluation of primary site lesions and metastatic lesions greater than 1 cm. Though 99mTc-DMSA (V) had higher uptake in the lesions as compared to [18F]FDG PET-CT, the only advantage [18F]FDG PET-CT had was that it could also detect subcentimeter lesions.

Optimized response prediction in esophagogastric junction adenocarcinomas (EGJAc) with combination of molecular biomarkers and FDG-PET.

1 Background: Predictive biomarkers (BMs) for EGJAc would optimise treatment selection and avoid ineffective therapy. Metabolic response (MR) defined as &gt;35% decrease in tumour FDG Standardized Uptake Value (SUV) between day 0 &amp; 14 after starting chemotherapy has a high negative predictive value (95%) for response, but limited positive predictive value (50%). Combining molecular BMs with FDG-PET may optimise response prediction. We used global gene expression profiling (GEP) to identify molecular BMs that when combined with FDG-PET would improve predictive accuracy. Methods: 28 patients with locally advanced or metastatic EGJAc received platinum based chemotherapy (PBC). FDG PET CT scans were at day 0 and day 14 and GEP (Affymetrix ST1.0 Exon Genechips) on day 0 tumour biopsies. A tissue microarray comprising an independent set of 154 OGJAc who underwent surgery +/− neoadjuvant PBC was used with immunohistochemistry (IHC) for qualification of GEP results. Radiological response was assessed after 3/ 4 cycles of PBC by RECISTv1.1. Results: We identified a gene expression signature (86 genes) that separated FDG PET MR patients(&gt;35% fall SUV day 0 to14) into those that do and do not go on to have a RECIST response. In cross validation, this signature correctly predicted response in 28/28. Pathway analysis on GEP data identified potential novel mechanisms of response, including the Leptin pathway. Leptin mRNA was higher in FDG metabolic responders who did not have a RECIST response compared to those that did. In the independent set, high Leptin protein by IHC was strongly associated with lack of histopathologic response to neoadjuvant PBC (n=64, p=0.002). High Leptin expression also had a therapy independent prognostic effect with longer survival in the absence of histopathologic response or with no neoadjuvant PBC and in low Leptin patients poor survival was mitigated to a certain extent by neoadjuvant PBC (n=154, Kaplan-Mieier, log rank p=0.041 &amp; Cox MVA p=0.040). Conclusions: Molecular biomarkers (Leptin in particular) combine with FDG PET to optimise response prediction in EGJAc. Further investigation of this combined molecular and imaging approach is warranted.

Long-Term Survival, Toxicity Profile, and role of F-18 FDG PET/CT scan in Patients with Progressive Neuroendocrine Tumors Following Peptide Receptor Radionuclide Therapy with High Activity In-111 Pentetreotide

Aim: To study the long term benefits, toxicity and survival rate in patients with neuroendocrine tumors receiving multiple cycles of high activity In-111 Pentetreotide therapy. Moreover, our secondary aim was to evaluate the value of F-18 FDG PET-CT scan as prognostic indicator in this group of patients.Background: Neuroendocrine tumors are a heterogeneous group of malignancies which are usually metastatic at diagnosis. Standard chemotherapy in these patients is associated with appreciable adverse events and low effectiveness. Since 1990s, Peptide receptor radionuclide therapy (PRRT) with radio-labeled somatostatin analogues has been introduced as a new method of treatment in patients with unresectable and/or metastatic neuroendocrine tumors expressing high levels of Somatostatin receptors.Methods: 112 patients with progressive disseminated and unresectable neuroendocrine tumor (stage III and stage IV) were enrolled in a non-randomized trial in an out-patient setting. High activity In-111 Pentetreotide (500 mCi (18.5 GBq) per cycle) was administered as an intravenous infusion over 3 hours and repeated therapy cycles every 9-12 weeks in eligible patients up to maximum of 4 cycles. Response to therapy was evaluated by clinical imaging using the RECIST criteria, metabolic criteria and patient's quality of life questionnaire. Dosimetry and biodistribution studies were also performed. Finally, Kaplan-Meier survival analysis was performed for patients followed for greater than 12 months. The relationship between pretreatment F-18 FDG PET-CT scan status and survival was determined by two-tailed Student's t-test in 42 patients who underwent pre-therapy PET scans.Results: For an average of 25 (median 18.65) months following the therapy, patients were evaluated for any evidence of toxicity. No significant acute toxicity was observed in patients. Grade II or III hematological toxicity (7.6% of patients), liver toxicity (18.4%) and also grade I renal toxicity (6.1%) was observed in 92 evaluable patients. Radiological responses were evaluated for an average of 29 months following their last cycle of therapy and results were analyzed by the RECIST criteria. Majority (85%) of patients had stable disease (SD), partial response (PR) rate was 7.5% and progressive disease (PD) was observed in 7.5% of patients. The average survival was 24.67 months after 2 cycles of therapy, 30.53 months after 3 cycles of therapy and 30.19 months after 4 cycles of therapy. Of the 42 patients who had pretreatment PET-CT imaging, 31 patients had positive F-18 FDG scans (SUV > 2.5) with an average survival time of 18.9 months (range 1.4-45.8 months) and 11 patients had negative F-18 FDG scans (SUV ≤ 2.5) with an average survival time of 31.8 months (range 7.4-42.9 months). Survival times for FDG negative patients were significantly longer than those for FDG positive patients (p = 0.001 with 95% confidence).Conclusion: High activity In-111 therapy is a safe and effective therapy for patients with progressive disseminated neuroendocrine tumors. No major hematological, renal and hepatic toxicities were observed. There was an increase in survival time particularly in patients with lower degree of liver involvement as well as patients who received three or more cycles of therapy, as compared to historical data. Pre-treatment FDG status may be a predictor of survival following In-111 pentetreotide therapy.