FDG PET-CT Imaging Research Articles

The Effect of Patient Age on Standardized Uptake Value-Hounsfield Unit Values of Male Genitourinery Structures In F-18 FDG PET/CT

Objective: Relation between patient age and Hounsfield Unit (HU),which is the linear attenuation coefficient, and Standardized Uptake Values (SUV) which is the amount of 18F-fluorodeoxyglucose (F-18 FDG) uptake, measured in the areas of interest drawn to prostate, seminal vesicles and testicles in F-18 FDG Positron Emission Tomography/Computed Tomography (PET/CT) images was investigated.Material and Methods: Mean and maximum SUV and HU values were recorded from the areas of interest (min 12 mm in diameter) which showed FDG uptake in prostate, seminal vesicles and testicles from F-18 FDG PET-CT images of 21 male patients under 40 years without genitourinary cancer. The effect of patient age to SUV and HU values was examined with Pearson correlation test using SPSS program.Results: There was a negative insignificant correlation between patient age and SUV and HU values for prostate. For seminal vesicles, correlation between patient age and SUV values and HUmax were positive but insignificant, while correlation with HUmean was significant (r=0.459, p=0.00). Correlation between patient age and SUVmax and SUVmean values were significant for testicles (r=0.506, p=0.002 and r=0.467, p=0.005, respectively) but the correlation between patient age and HUmax and HUmean values was not significant.Conclusion: F-18 FDG uptake in testicles in males increases with age until 40, suggesting an increase in metabolic rate. The significant correlation between age and mean HU values is probably caused by thickening of the tissue without an increase in glucose metabolism in seminal vesicles. In prostate, the effect of patient age to SUV and HU values was not observed until the age 40. Conflict of interest:None declared.

The Clinical Utility of FDG PET-CT in Evaluation of Bone Marrow Involvement by Diffuse Large B Cell Lymphoma

Abstract 2661 Background.In lymphoma, bone marrow (BM) involvement is a sign of extensive disease and BM biopsy is a standard method in the evaluation of BM infiltration by disease. Because of patchy BM involvement pattern by lymphoma, the reported rates of unilateral involvement in bilateral biopsies range from 10% to 50%. However BM biopsy is an invasive and painful procedure. The value of unilateral versus bilateral BM biopsy remains controversial. Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) is a noninvasive imaging technique and currently it shows potential to detect BM involvement by lymphoma. Aims. We assess the abilities of FDG PET-CT to ascertain the presence of BM involvement in diffuse large B cell lymphoma (DLBCL) patients and to define the possibility that bilateral BM biopsies could be replaced by unilateral biopsy for DLBCL staging workup. Methods. We retrospectively reviewed medical records of histologically proven DLBCL patients from 2004 through 2010 at the Asan Medical Center and Hallym University Medical Center. All patients were examined by FDG PET-CT and bilateral BM biopsy at both posterior iliac crests for initial staging workup. Evaluation of PET studies was performed by board-certified nuclear medicine physicians of each institution. Quantitative analysis of FDG uptake was not performed. Data were expressed in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for FDG PET-CT in evaluation of BM involvement by DLBCL, using BM biopsy as the reference standard. Two sets (right & left biopsy site) of pathologic and imaging data were analyzed separately. Results. Study population comprised 478 patients (median age 57, range 17–85 years; 269 male) with newly diagnosed DLBCL. Ann Arbor stage I, II, III and IV patients were 96, 120, 40 and 222, respectively. Overall, BM involvement by DLBCL that confirmed by bilateral BM biopsy occurred in 63 patients (13.2%, 15, 12, and 36 at right, left and both side biopsy, respectively). From the data of right side biopsy and FDG PET-CT images, comparison of the former and the later results revealed concordant positive findings in 22 cases (4.6%) and concordant negative findings in another 418 cases (87.4%). In 29 patients (6.1%) in whom FDG PET-CT returned findings of normal marrow, iliac crest BM biopsy revealed lymphomatous infiltration. On the other hand, in 9 patients (1.9%) in whom bilateral iliac crest BM biopsy had failed to reveal any abnormality, FDG PET-CT showed increased uptake. The calculated values for FDG PET-CT in evaluation of right BM infiltration were 43.1% (22/51) of sensitivity, 97.9% (418/427) of specificity, 71% (22/31) of PPV and 93.5% (418/447) of NPV. The values oriented from left BM biopsy and FDG PET-CT images were similar (sensitivity 41.7% (20/48), specificity 97.9% (421/430), PPV 69% (20/29), NPV 93.7% (421/449)). Conclusions. This study has the largest DLBCL cases among ever reported articles, and demonstrates not excellent sensitivity of FDG PET-CT against the results of BM biopsy for the detection of BM involvement in DLBCL patients. BM biopsy could not be completely replaced with FDG PET-CT. But it has relatively good PPV, FDG PET-CT will be a useful tool for image-guided biopsy for DLBCL staging. And in daily practice, clinicians could consider the possibility to do efficient unilateral BM biopsy for DLBCL patients who have increased posterior iliac crest FDG uptake, instead of bilateral biopsy. Disclosures:Kim:Novartis: Research Funding.

Newly diagnosed and relapsed follicular lymphoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Newly diagnosed and relapsed follicular lymphoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Residual metabolic tumor activity after chemo-radiotherapy is mainly located in initially high FDG uptake areas in rectal cancer

Purpose Recent literature suggests that tumor cells and areas within tumors with a high initial FDG uptake might be more resistant to (chemo)radiotherapy ((C)RT). This study was undertaken to test this hypothesis in rectal cancer using rigid and non-rigid image registration. Patients and methods Twenty-eight patients, diagnosed with locally advanced rectal cancer and referred for pre-operative treatment with CRT were included in this study. All patients underwent FDG-PET–CT imaging prior to and after CRT. Rigid and non-rigid image registration was performed to compensate organ deformations between the pre- and post-treatment PET–CT scans. The tumor was contoured on both PET-scans using SUV iso-contouring based on the SBR-method. The voxels with residual increased FDG uptake were studied and correlated to their pre-treatment FDG uptake level. Two SUV–volume-histograms were made based on the pre-treatment PET-data, one for the voxels within the pre-treatment tumor PET-based iso-contour and one for the voxels within the PET-based iso-contour of the residual tumor non-rigidly registered onto the pre-treatment scan. Results For the voxels with a pre-treatment FDG uptake of >50% of SUV max, 70.6 ± 5.6% of the voxels were still metabolic active in the residual tumor, whereas for voxels with an FDG uptake of <50% of SUV max only 51.1 ± 6.7% were present in the metabolic active residual tumor. Conclusion This study presents areas in rectal tumors with an initially high FDG uptake to be most likely to show residual disease after CRT. This could indicate a higher (C)RT-resistance for tumor regions with a high FDG uptake prior to treatment.

Result of FDG PET-CT Imaging After Immunochemotherapy Induction Is a Powerful and Independent Prognostic Indicator of Outcome for Patients with Follicular Lymphoma: An Analysis From the PRIMA Study

AbstractAbstract 855 Aim:Despite its often indolent clinical course, follicular lymphoma (FL) is a heterogeneous disease. Current criteria for early identification of patients with a poor prognosis are suboptimal - the FLIPI and F2 index are insufficient prognostic markers for individual patients and the limitations of post-treatment conventional response criteria have long been acknowledged. FL shows increased FDG uptake, but unlike DLBCL, minimal data exist about the role of PET-CT in response assessment. We have used the prospective conventional response assessment and 42 month patient follow-up in the PRIMA (Primary Rituximab and Maintenance, Salles et al., ASCO 2010, Abstr#8004) study as a platform for analysis of the utility of PET-CT in FL. Methods:The PRIMA database was interrogated and investigators surveyed to identify PET-CT scans performed during staging and induction response assessment. Single modality PET-only scans were not eligible for inclusion. Local PET interpretation (positive + or negative -) was used to explore associations with patient outcomes. The primary endpoint was PFS from PRIMA registration. Results:277 PET-CT scans on 160 patients from 40 centres were identified. Baseline patient characteristics did not differ from the overall PRIMA patient population. Positive PET-CT scans were recorded in 119/120 (99%) at diagnosis, 11/33 (33%) interim restaging scans and 32/124 (26%) post induction treatment (R-CHOP or R-CVP).There was significant correlation between PET-CT result and conventional response assessment at the end of immunochemotherapy (p<0.0005). The incidence of post-treatment PET+ increased across the categories of lesser conventional responses, occurring in 8% (4/50) CR, 31% (12/39) CRu, 41% (11/37) PR, 67% (2/3) SD, and 80% (4/5) PD. While 73/91 (80%) of PET- patients were in CR/CRu, given the very high overall response rate on study, 16/33 (48%) of the PET+ population were also in CR/CRu.With a median follow-up of 42 months, a significantly inferior actuarial 3yr PFS was observed in post-treatment PET+ vs. PET- patients (Figure 1): 32% (95% CI 17–48%) vs. 74% (95% CI 63–82%) (log rank p<0.0001, HR 3.5, 95% CI 2.0–6.1), median PFS 19 months (13-35) vs. not reached, (52-NR).Using proportional hazard regression analysis, both conventional response (overall p=0.0002) and PET+ status (HR 2.8 p=0.0007) were significant predictors of inferior PFS. However, the predictive power of conventional response assessment was limited to non-responders: SD/PD vs. CR/CRu (HR 6.5, p<0.0001), and SD/PD vs. PR (HR 5.2, p=0.0009). Comparison of PR vs. CR/CRu was not different (HR 1.2, p=0.5). While PET+ status had a significant negative impact on PFS in both the CR/CRu (HR 2.6, p=0.015) and PR (HR 4.3 p=0.018) patient groups, there was no difference in outcome between CR/CRu vs. PR patients within the PET+ (HR 1.5 p=0.42) and PET- (HR 1.0 p=0.98) subgroups.When only patients randomised for the maintenance element of the PRIMA study were considered, post-treatment PET+ (15/59) remained predictive of 3yr PFS (27 vs. 69%, HR 3.1, p=0.005) in the observation arm, but post-treatment PET+ (9/47) was not significantly associated with an adverse outcome in patients receiving rituximab maintenance (3-year PFS 56 vs. 81%, HR 2.2, p= 0.18).In a multivariate Cox model including responding patients the following factors were negative predictors of PFS: post-treatment PET+ (HR 3.1 p<0.0014); R-CVP induction therapy (HR 2.8, p<0.014); and baseline β2M ≥3 (HR 2.6 p<0.0042), while conventional PR and FLIPI were not. Conclusion:This PRIMA sub-study demonstrates that post-treatment PET-CT is a powerful predictor of PFS that complements conventional response evaluation after first line immunochemotherapy for FL. Patients who are PET- can expect a prolonged PFS whether in conventional CR or PR, but for those remaining PET+, with a median 19 month PFS, the disease cannot be characterized as indolent. Future clinical trials should evaluate an FDG PET-CT response adapted approach focused on improving outcomes for this group. [Display omitted] Disclosures:Seymour:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Shpilberg:Roche: Consultancy, Honoraria.

Simultaneous positron emission tomography (PET) assessment of metabolism with 18F-fluoro-2-deoxy- d-glucose (FDG), proliferation with 18F-fluoro-thymidine (FLT), and hypoxia with 18fluoro-misonidazole (F-miso) before and during radiotherapy in patients with non-small-cell lung cancer (NSCLC): A pilot study

Objectives To investigate the changes in tumour proliferation (using FLT), metabolism (using FDG), and hypoxia (using F-miso) during curative (chemo-) radiotherapy (RT) in patients with non-small-cell lung cancer (NSCLC). Patients and methods Thirty PET scans were performed in five patients (4 males, 1 female) that had histological proof of NSCLC and were candidates for curative-intent RT. Three PET-CT (Biograph S16, Siemens) scans were performed before ( t 0) and during (around dose 46 Gy, t 46) RT with minimal intervals of 48 h between each PET-CT scan. The tracers used were 18fluoro-2deoxyglucose (FDG) for metabolism, 18fluorothymidine (FLT) for proliferation, and 18F-misonidasole (F-miso) for hypoxia. The 3 image sets obtained at each time point were co-registered (rigid: n = 9, elastic: n = 1, Leonardo, TrueD, Siemens) using FDG PET-CT as reference. VOIs were delineated (40% SUV max values were used as a threshold) for tumours and lymph nodes on FDG PET-CT, and they were automatically pasted on FLT and F-miso PET-CT images. ANOVA and correlation analyses were used for comparison of SUV max values. Results Four tumours and twelve nodes were identified on initial FDG PET-CT images. FLT SUV max values were significantly lower ( p < 0.0006) at t 46 in both tumours and nodes. The decrease in FDG SUV max values had a trend towards significance ( p = 0.048). F-Miso SUV max values were significantly higher in tumours than in nodes ( p = 0.02) and did not change during radiotherapy ( p = 0.39). A significant correlation was observed between FLT and FDG uptake ( r = 0.56, p < 10 −4) when all data were pooled together, and they remained similar when the before and during RT data were analysed separately. FDG and F-miso uptakes were significantly correlated ( r = 0.59, p = 0.0004) when all data were analysed together. The best fit was obtained after adjusting for lesion type (tumour vs. node). This correlation was observed for the SUV max measured during RT ( r = 0.70, p = 0.008) but not for the pre-RT data ( r = 0.19, p = 0.35). The weak correlation between FLT and F-miso uptakes only became significant ( r = 0.66, p = 0.002) when the analysis was restricted to the data acquired during RT. Conclusion Three different PET acquisitions can be performed quasi-simultaneously (4–7 days) before and during radiotherapy in patients with NSCLC. Our results at 46 Gy suggest that a fast decrease in the proliferation of both tumours and nodes exists during radiotherapy with differences in metabolism (borderline significant decrease) and hypoxia (stable).

Relapsing acute myeloid leukemia beginning with a penile localization

We report the case of a 52-year-old man who was diagnosed for an acute myeloid leukemia (FAB classification: M1) with abnormalities in conventional caryotype showing trisomy 7 and recombination of MLL-AML1. His leukemia was discovered in front of neutropenic fever and circulating blastic cells. He was first treated with three cycles of intensive chemotherapies using high doses of cytarabine and idarubicine in association, followed by a nonmyeloablative allogeneic bone marrow-related transplantation based on busulfan and fludarabine conditioning. He relapsed 2 months later with pancytopenia and was, therefore, treated with a myeloablative bone marrow-related transplantation using melphalan 200 mg/m conditioning. He stayed in complete clinical and cytological remission for 16 months, without any signs of GVHD. He then started to complain of a painfull spot on his penis. On examination, he had first a nodular painful lesion of the dorsal side of the penis, with no contiguous lymph nodes. No peripherical or medullar blastic infiltration was seen. Axial and sagittal fused FDG PET-CT images showed an intense and isolated FDG uptake of the distal corpus cavernosa (Image 1A). A surgical excision with anatomopathological analysis confirmed the leukemic origin of the lesion showing myeloblastic cells CD34 1 (Image 1B). The margins were safe from leukemia cells. However, even before beginning a treatment, he relapsed with a bilateral infiltration of corpus cavernosa, the penile skin, and an inguinal adenopathy. Because surgery did not limit the extension of leukemia as already report, treatment consisted in an association of a systemic donor lymphocytes injection with gemtuzumab ozogamicin (at 3 mg/ṁ) and a local radiotherapy at 40 Gy on penis and 30 Gy onto the inguinal lymph node areas, seen on sagittal CT-scan (Image 1C). A complete local remission was observed, but 3 months later, a new relapse in the gums was observed. A palliative therapy was begun, but he died 2 months later from a severe dyspnoea, due to a blastic localization in oropharynx and blastic hyperleucocytosis at 50G/L. To date, only five cases of penile localization of acute leukemia have been listed: two of them were AML [1,2]. There were all FAB M4 subtype, and the penile metastasis was seen at relapse. The first patient was treated with radiotherapy exclusively and the second by surgery, but the two patients died for disseminated disease. Three others Image 1. A: Sagittal and axial FDG PET-CT, with fused images, showing intense nodular FDG uptake of the distal corpus cavernosa. B: Massive tissue infiltration by myeloblastic cells, confirmed by positive CD34 staining. C: First dosimetry planning for radiotherapy treatment. Sagittal CT-scan showing important oedema of all the penis. Radiotherapy treatment neaded two other dosimetry planning due to the good results it gave.

Response and survival in oesophageal cancer patients following neoadjuvant chemotherapy assessed by FDG-PETCT imaging and corelation to pathologic response.

e14571 Background: Combined positron emission tomography with computed tomography(PETCT) using [18F] 2-fluoro-2-deoxy-D-glucose (FDG) is an important modality for staging oesophageal cancer and may also predict pathological response to chemotherapy. We therefore conducted this retrospective review to assess the relationship between metabolic response measured by FDG-PETCT imaging following neoadjuvant chemotherapy in oesophageal cancer and survival. Methods: Oesophageal cancer patients presenting to Northern Ireland Cancer Centre between January 2003 to December 2008, who had FDG-PETCT assessment for staging and also following neoadjuvant chemotherapy before surgery were included. Routine FDG-PETCT findings were collated and metabolic response (≥ 35% reduction in the tumour standard uptake values[SUV]), evaluated. Pathologic response was assessed and stratified into five histological tumour regression grades (TRG1-5). TRG 1 and 2 groups were classified as pathological responders. Overall survival and event-free survival were obtained. Results: 81 patients with a median age of 66 years (28-77) were identified. 66 (81%) had oesophageal carcinoma and 15 (19%) had Siewart type I or type II oesophageal-gastric junction (OGJ) carcinomas. Metabolic response was identified in 67 (82.3%) of patients. After a median follow up of 25.0 months, the median overall survival in metabolic responders has not been reached. In the metabolic non responders the median overall survival was 15.7 months (p 0.005), (HR = 2.66, 95%CI 1.31-5.41) and median event-free survival was also 15.7 months (p 0.023), (HR = 2.14, 95%CI 1.09-4.21). Pathological response was seen in 14 (17.9%) and this correlates poorly with metabolic response. There is no statistically significant relationship between pathologic response and survival. Conclusions: Metabolic nonresponse to neoadjuvant chemotherapy measured by FDG-PETCT appears to be associated with a poor survival. Further work will seek to identify a molecular signature for lack of response to preoperative chemotherapy in order to minimise exposure of patients to toxic treatment where they are unlikely to benefit. No significant financial relationships to disclose.

Cardiac T-Cell Lymphoma Imaged With F-18 FDG PET-CT and Correlative Imaging

Primary cardiac tumors are rare, and of these, primary cardiac lymphomas account for less than 1%. Most are B-cell non-Hodgkin lym- phomas, and the right atrium and right ventricle are the most frequently involved sites. The clinical presentation varies, but commonly involves pericardial effusions, AV block, valvular dysfunction, or heart failure. We present a 72-year-old man who was referred for an F-18 FDG PET-CT scan to evaluate a cardiac mass. An intensely hypermetabolic mass was observed replacing most of the right ventricle, which was confirmed with a contrast- enhanced CT as well as magnetic resonance imaging. Endomyocardial biopsy revealed a low-grade T-cell lymphoma. This is a rare report of a cardiac T-cell lymphoma imaged with F-18 FDG PET-CT.

Blood glucose level normalization and accurate timing improves the accuracy of PET-based treatment response predictions in rectal cancer

Purpose To quantify the influence of fluctuating blood glucose level (BGLs) and the timing of PET acquisition on PET-based predictions of the pathological treatment response in rectal cancer. Material and methods Thirty patients, diagnosed with locally advanced-rectal-cancer (LARC), were included in this prospective study. Sequential FDG–PET–CT investigations were performed at four time points during and after pre-operative radiochemotherapy (RCT). All PET-data were normalized for the BGL measured shortly before FDG injection. The metabolic treatment response of the tumor was correlated with the pathological treatment response. Results During RCT, strong intra-patient BGL-fluctuations were observed, ranging from −38.7 to 95.6%. BGL-normalization of the SUVs revealed differences ranging from −54.7 to 34.7% ( p < 0.001). Also, a SUV max time-dependency of 1.30 ± 0.66 every 10 min (range: 0.39–2.58) was found during the first 60 min of acquisition. When correlating the percent reduction of SUV max after 2 weeks of RCT with the pathological treatment response, a significant increase ( p = 0.027) in the area under the curve of ROC-curve analysis was found when normalizing the PET-data for the measured BGLs, indicating an increase of the predictive strength. Conclusions This study strongly underlines the necessity of BGL-normalization of PET-data and a precise time-management between FDG injection and the start of PET acquisition when using sequential FDG–PET–CT imaging for the prediction of pathological treatment response.

Prognostic Significance of Positron Emission Tomography (FDG-PET) at Baseline and After 4 Cycles of R-CHOP in 75 Patients with Mantle Cell Lymphoma Treated with Intensive Chemotherapy and Autologous Stem Cell Rescue.

Abstract 1226Poster Board I-248 BackgroundThe value of FDG-PET in mantle cell lymphoma (MCL) has not been addressed in a homogeneous group of pts. The optimal initial therapy is controversial; however, intensified therapy followed by consolidation with high-dose therapy and autologous stem cell rescue (HDT-ASCR) is associated with superior progression-free survival (PFS) compared to CHOP-based therapy. In this study, we examined the prognostic value of FDG-PET in a group of uniformly treated pts with upfront HDT-ASCR consolidation. The role of FDG-PET was evaluated: at baseline; as a predictor of proliferation index (PI); and as interim evaluation after induction therapy prior to HDT-ASCR. Pts and MethodsPts received sequential therapy consisting of sequential R-CHOP-14 × 4 followed by RICE x 2-3 cycles and consolidation with HDT-ASCR. FDG-PET and diagnostic CT imaging was obtained at baseline and after R-CHOP (N=75). The number of cycles of RICE was determined by the PET and CT response after induction with R-CHOP-14×4; pts with FDG-avid disease received a third cycle. Additional therapy was administered in 10 pts who had persistent FDG-avid disease after RICE with the objective of achieving the best response prior to the HDT-ASCR. Therapy included bortezomib in 7 cases and other treatment in 3 cases. The PI was determined by quantitative image analysis of Ki-67 stained slides (N=39). The median follow-up was 3.4 years. ResultsThe median age was 59 years, 71% had bone marrow disease and 85% had stage 4 disease. According to the MIPI score, 50% had low-risk, 35% had intermediate-risk and 15% had high-risk disease. The baseline FDG-PET was positive in 71 pts (95%) and the median SUV was 5.5 (1.6-14). The baseline SUV was not prognostic after the stratification of the pts by the median SUV (PFS 81% vs 84% and overall survival (OS) 100% vs 74%, p=0.15). The median PI was 22% for the pts with an SUV below the median and 36% for the other group (P=0.03, Mann-Whitney). Interim FDG-PET evaluation after induction with R-CHOP-14 was available in 69 pts among the 71 with a positive test at baseline, the exam was negative in 49 pts (71%). A negative interim FDG-PET was associated with a better PFS (84% v 40% at 4years, p<0.0001) and a better OS (94% v 70% at 4 years, p=0.019). When FDG-PET results were added to response determined by CT scan, there was no difference in PFS between FDG-PET negative with either a CT CR (N=28) or CT PR (N=20) (91% vs 73% at 4 years, P=0.89). In contrast, patients with a CT PR had an inferior PFS and OS when the FDG-PET was positive (N=19) compared when the FDG-PET was negative (42% vs 76% at 4 years, P=0.008). The 4-year OS was 96% for FDG-PET negative CT CR, 91% for FDG-PET negative CT PR and 70% for FDG-PET positive CT PR (P=0.08). ConclusionsIn MCL, a baseline FDG-PET is useful as not all cases are positive. Though SUV correlates with the PI, the pretreatment SUV alone is not prognostic. Pts in PR by CT are separated by the FDG-PET result with negative pts having a superior outcome. The interim FDG-PET after induction with R-CHOP-14 × 4 is prognostic for PFS and OS in a program of sequential therapy with upfront consolidation with HDT/ASCR. DisclosuresNo relevant conflicts of interest to declare.

F-18 FDG PET-CT Imaging in Gastric Sarcoma

We report the F-18 fluorodeozyglucose positron emission tomography computed tomography appearance of a biopsy-proven primary gastric sarcoma in a 24-year-old man who presented with early satiety, dyspepsia, and weight loss. Gastric sarcoma is a rare form of malignancy constituting approximately 0.3% to 8% of malignant soft tissue tumors of the stomach. The tumor appears as an ill-defined heterogeneous mass protruding off the lesser curvature of the stomach on computed tomography with central photopenia and peripheral intense uptake on positron emission tomography images.

2111 Response and survival in oesophageal cancer patients following neoadjuvant chemotherapy assessed by FDG-PETCT imaging

2111 Response and survival in oesophageal cancer patients following neoadjuvant chemotherapy assessed by FDG-PETCT imaging

Orthopedic surgery-related benign uptake on FDG-PET: case examples and pitfalls

Orthopedic surgical procedures often create some special postoperative complications, which may demonstrate abnormally increased or focal uptake for an extended period of time on FDG PET-CT images. The distinction of normal from pathologic, benign from malignant uptake is very important to minimize the number of false positive results. To date, very little data have been published regarding surgical-related benign musculoskeletal uptake on PET-CT imaging. In this paper, we present to the readers some case examples of FDG PET-CT imaging for postoperative fracture, infection or osteomyelitis, metallic implants, aggressive bone edge, heterotopic ossification, granuloma and neuroma. We also discuss potential pitfalls to recognize these orthopedic surgery-related complications and identify benign nature of increased FDG uptake. In all cases, the patient's medical and surgical history would be of paramount importance to the radiologists/nuclear medicine physicians who interprets the scan. It is also crucial to carefully correlate FDG uptake with the anatomy on the co-registered CT images in all transaxial, coronal and sagittal views in order to identify the location and pattern of uptake.

Relationship between primary lesion FDG uptake and clinical stage at PET–CT for non-small cell lung cancer patients: An observation

The aim of the present study was to investigate the relationship between FDG uptake and clinical stage for non-small cell lung cancer. The patients who were histologically or cytologically proven to be adenocarcinoma (AC) or squamous cell carcinoma (SCC) lung cancer and conducted FDG PET/CT staging were retrospectively reviewed. The FDG uptake was quantified as the maximum standardized uptake value (SUVmax). And the T-N-M status was determined mainly by FDG PET–CT imaging according to the 1997 update of the international staging system for lung cancer. From December 2003 to November 2007, 266 cases (194 men and 72 women; age range 31–90 years, median 62 years) were analyzed, which included 161 AC and 105 SCC patients. The present study showed that both size (3.23 ± 1.68 cm vs 2.63 ± 1.33 cm, P = 0.004) and SUVmax (9.82 ± 5.08 vs 8.43 ± 4.21, P = 0.016) were significantly greater for SCC compared to AC. There was positive correlation between the SUVmax and size for both SCC and AC ( r = 0.651, 0.632, respectively; both P = 0.000). Significant difference is found among different stages in SUVmax for AC ( F = 11.693, P = 0.000) but not for SCC ( F = 1.514, P = 0.216). After controlling the size factor, a significant correlation was found between tumor stage and FDG uptake value for AC ( r = 0.323, P = 0.000), but not for SCC ( r = 0.113, P = 0.252). In conclusion, this observation showed that tumor size and histologic subtype had influences upon FDG uptake in non-small cell lung cancer. It demonstrated significant correlation between clinical stage and SUVmax for AC, but not for SCC.

F-18 FDG PET-CT Imaging in Recurrent Cerebral Gliosarcoma

We report the F-18 FDG PET-CT appearance of recurrent gliosarcoma (GS) with extracranial extension in a 47-year-old man who underwent surgical resection of a right frontal GS 5 months earlier. F-18 FDG PET demonstrated moderate uptake in the recurrent disease. GS is a very rare, biphasic primary neoplasm of the central nervous system, composed of glioblastoma multiforme mixed with a sarcomatous component. It occurs in adults of middle age and carries a poor prognosis. The median survival reported is less than a year. The results suggest that F-18 FDG PET imaging may be useful in detecting recurrent GS.

PET-CT findings in large vessel vasculitis presenting as FUO, a case report

There are increasing data demonstrating the role of flourodeoxyglucose positron emission tomography with computerized tomography fusion ((18)FDG PET-CT) in the diagnosis of large vessel vasculitides, including Takayasu arteritis and giant cell arteritis (Hara et al. 1999; Blockmans et al. 1999; Turlakow et al. 2001]. We report a case of large vessel giant cell arteritis involving the major branches of the aorta as detected on (18)FDG PET-CT. A 56-year-old woman returning to the USA after visiting her native Iraq presented to our rheumatology department with fever of unknown origin (FUO) of 2-month duration, night sweats, and arthralgias. The patient did not have claudication; systolic blood pressure measurements demonstrated a 20-mmHg difference between her arms. Infectious disease, malignancy, and collagen vascular disease workup was unrevealing. Temporal artery and bone marrow biopsies were negative. To exclude FUO of malignancy, (18)FDG PET-CT imaging was performed. The images demonstrated significant (18)FDG uptake (indicating increased metabolic activity) in a circumferential fashion along the aorta and its major braches, including the carotid, subclavian, and common iliac arteries. Contrast-enhanced CT imaging demonstrated wall thickening involving these vessels along with left subclavian vein thrombosis and findings consistent with superficial thrombophlebitis involving the right forearm, wrist, and hand. The combination of laboratory and imaging findings, including the characteristic inflammatory changes involving the large vessel walls as seen on CT, as well as the vessel wall hypermetabolism on FDG PET indicating active inflammation, resulted in the diagnosis of large vessel giant cell arteritis. The patient was treated with high-dose corticosteroids followed by a course of Immuran. Her symptoms resolved and a follow-up FDG PET-CT showed complete resolution of the large vessel hypermetabolism. (18)F-FDG PET-CT can be a useful and noninvasive tool in diagnostic evaluation of FUO by excluding a malignant etiology and providing unexpected information that aids in correct diagnosis.

Abstract No. 339: Prospective Semiquantitative Analysis of FDG PET-CT Imaging Feature at 3 and 6 Months After RFA of Lung Tumors

Abstract No. 339: Prospective Semiquantitative Analysis of FDG PET-CT Imaging Feature at 3 and 6 Months After RFA of Lung Tumors

F-18 FDG PET-CT Imaging of Intestinal Metastasis From Primary Lung Cancer

Intestinal metastasis of lung cancer was diagnosed in a 67-year-old man with palpable masses in the axilla and lower abdomen. F-18 FDG PET/CT showed a large cavitary mass with an SUV of 14.1, which was similar to that of the lung mass, in the left lower quadrant of peritoneal cavity. Intestinal metastasis is rarely found, although symptoms related to the digestive tract are not uncommon in patients with lung cancer. Physicians should be aware of this possibility because a small intestinal metastasis often perforates, leading to life-threatening peritonitis.

Improved Discrimination of Benign and Malignant Lesions on FDG PET/CT, Using Comparative Activity Ratios to Brain, Basal Ganglia, or Cerebellum

This study demonstrates a simple background correction method, which improves the discrimination of benign from malignant lesions on FDG PET-CT imaging, using activity ratios compared with brain, basal ganglia, or cerebellum. Standardized uptake values (SUVs) and comparative activity ratios (CARs) were determined for FDG uptake in 92 lesions (39 benign and 53 malignant) in 49 patients. Reference tissues included cerebral cortex, basal ganglia, cerebellum, lung, liver, and aortic blood pool. Discriminant power for each CAR was evaluated as malignant-to-benign ratio of mean uptake and ratio of intermediate-likelihood lesions to total number of lesions. Uncorrected SUV varied widely for malignant and benign lesions, with considerable overlap. Ratio of mean uptake for malignant lesions versus benign lesions was lowest for uncorrected SUVAVG and SUVAVG/liver (1.92), and highest for SUVMAX/cerebral cortex (3.52). Lesions could be separated into very high (> 90%), very low (< 10%), and intermediate (> or = 10% and < or = 90%) likelihood of malignancy. The ratio of intermediate-likelihood lesions to the total number of lesions was greatest for SUVAVG (0.42) and lowest for SUVMAX/basal ganglia (0.22). Ability to discriminate malignant from benign lesions was enhanced by using CARs derived from cerebral cortex, basal ganglia, or cerebellum. Using a 3-tiered diagnostic schema, most lesions could be assigned to categories of very high or very low likelihood of malignancy, with a significant reduction in indeterminant lesions, compared with uncorrected SUV.