Role of (18)F-FDG PET/CT in the evaluation of response to antibiotic therapy in patients affected by infectious spondylodiscitis.

OBJECTIVE: Spondylodiscitis is characterized by infection involving the intervertebral disc and adjacent vertebrae. It can occur anywhere in the vertebral column but more commonly involves lumbar spine. Our aim was to evaluate the usefulness of (18)F-FDG PET/CT to detect the early response to antibiotic therapy in patients affected by infectious spondylodiscitis and to compare the role of (18)F-FDG PET/CT and MRI in post-treatment evaluation. MATERIALS AND METHODS: 15 patients (12M, 3F), with mean age 65±13 years old, with typical clinical symptoms of Infectious Spondylodiscitis (pain, fever and increase of inflammatory indexes) and confirmed by blood culture or vertebral biopsy underwent within three day-interval a (18)F-FDG PET/CT and Magnetic Resonance (MR) at "baseline" and after antibiotic therapy. Semiquantitative parameters at (18)F-FDG PET/CT "baseline" SUVmax1, MTV1 and TLG1 and after therapy SUVmax2, MTV2 and TLG2 of involved vertebrae were calculated. Follow-up period of at least three months was available for all patients. T-student test for paired groups was performed to compare baseline and after therapy (18)F-FDG PET/CT semiquantitative parameters. RESULTS: According to (18)F-FDG PET/CT parameters all patients showed a response to antibiotic therapy. All patients were positive at "baseline" MRI of the spine, while at follow-up, 7/15 patients showed MR signs of infection and were considered "positive" and 8/15 showed resolution of infectious condition and, therefore they were considered "negative". A statistical significant difference between (18)F-FDG PET/CT "baseline" and after antibiotic therapy was found for all semiquantitative parameters: SUVmax (t=5.8, P=0.01); MTV (t=5.17, P=0.001); TLG (t=5,26, P=0,001). The comparison between the "baseline" and "after treatment" (18)F-FDG semiquantitative parameters showed a significant reduction of all parameters. This reduction was relevant also in patients with positive post-treatment MRI. This can be probably related to the tissue remodeling in the very immediate phase post-treatment, resulted positive at MRI and negative at (18)F-FDG PET/CT. Clinical follow-up of at least three months confirmed these results. CONCLUSIONS: (18)F-FDG PET/CT is useful to detect the early response to antibiotic therapy in patients affected by infectious spondylodiscitis. (18)F-FDG PET/CT semiquantitative parameters provide critical diagnostic information of the infectious process. (18)F-FDG PET/CT should be considered as first-line exam in the early post-treatment evaluation of spondylodiscitis while MR should be preferred for delayed assessment.

Useful diagnostic biometabolic data obtained by PET/CT and MR fusion imaging using open source software.

In the last decade numerous attempts were considered to co-register and integrate different imaging data. Like PET/CT the integration of PET to MR showed great interest. PET/MR scanners are recently tested on different distrectual or systemic pathologies. Unfortunately PET/MR scanners are expensive and diagnostic protocols are still under studies and investigations. Nuclear Medicine imaging highlights functional and biometabolic information but has poor anatomic details. The aim of this study is to integrate MR and PET data to produce distrectual or whole body fused images acquired from different scanners even in different days. We propose an offline method to fuse PET with MR data using an open-source software that has to be inexpensive, reproducible and capable to exchange data over the network. We also evaluate global quality, alignment quality, and diagnostic confidence of fused PET-MR images. We selected PET/CT studies performed in our Nuclear Medicine unit, MR studies provided by patients on DICOM CD media or network received. We used Osirix 5.7 open source version. We aligned CT slices with the first MR slice, pointed and marked for co-registration using MR-T1 sequence and CT as reference and fused with PET to produce a PET-MR image. A total of 100 PET/CT studies were fused with the following MR studies: 20 head, 15 thorax, 24 abdomen, 31 pelvis, 10 whole body. An interval of no more than 15 days between PET and MR was the inclusion criteria. PET/CT, MR and fused studies were evaluated by two experienced radiologist and two experienced nuclear medicine physicians. Each one filled a five point based evaluation scoring scheme based on image quality, image artifacts, segmentation errors, fusion misalignment and diagnostic confidence. Our fusion method showed best results for head, thorax and pelvic districts in terms of global quality, alignment quality and diagnostic confidence,while for the abdomen and pelvis alignement quality and global quality resulted poor due to internal organs filling variation and time shifting beetwen examinations. PET/CT images with time of flight reconstruction and real attenuation correction were combined with anatomical detailed MRI images. We used Osirix, an image processing Open Source Software dedicated to DICOM images. No additional costs, to buy and upgrade proprietary software are required for combining data. No high technology or very expensive PET/MR scanner, that requires dedicated shielded room spaces and personnel to be employed or to be trained, are needed. Our method allows to share patient PET/MR fused data with different medical staff using dedicated networks. The proposed method may be applied to every MR sequence (MR-DWI and MR-STIR, magnet enhanced sequences) to characterize soft tissue alterations and improve discrimination diseases. It can be applied not only to PET with MR but virtually to every DICOM study.

[18F-FDG PET/CT in staging and restaging cholangiocarcinoma]. / La PET/TC con 18F-FDG nella stadiazione, diagnosi e ristadiazione del colangiocarcinoma.

The prognosis for hepatobiliary malignancies is dismal. Surgery remains the primary curative option. The positron emission tomography/computed tomography (PET/CT) provides simultaneous metabolic and anatomic information on tumors in the same imaging session. The role of PET/CT in detecting hepatobiliary malignancies has not yet been established. The purpose of this review was to examine the literature on the use of PET/CT in cholangiocarcinomas, also in order to improve the preoperative staging and the restaging, for a proper oncology management of patients.

[Peritoneal carcinomatosis from ovarian cancer: role of 18F-FDG-PET/CT and CA125]. / La carcinosi peritoneale da carcinoma ovarico: utilità della 18F-FDG-PET/TC e del biomarker CA125.

The purpose of this study was to evaluate the contribution of 18F-FDG-PET/CT in highlighting the peritoneal involvement in patients with ovarian cancer, also in relation to the biomarker CA125. We retrospectively analyzed 64 female patients with histological diagnosis of ovarian cancer who underwent 18F-FDG-PET/CT and CA125 measurement. Sensitivity and specificity of 18F-FDG-PET/CT were both 90.63% (95% CI: 80-100%). Sensitivity and specificity of CA125 were 93.33% (95% CI: 80-100%) and 33.33% (95% CI: 25-64%), respectively. In patients with peritoneal carcinomatosis from ovarian cancer, it is recommended to perform 18F-FDG-PET/CT, in particular when elevated CA125 levels are detected.

Immune Checkpoint Inhibitors in Advanced NSCLC: [18F]FDG PET/CT as a Troubleshooter in Treatment Response.

INTRODUCTION: The aim of this study was to investigate whether [18F]FDG PET/CT-derived semi-quantitative parameters can predict immunotherapy treatment response in non-small cell lung cancer (NSCLC) patients. Secondly, immune-related adverse events (irAEs) and lymphoid cell-rich organs activation were evaluated. MATERIALS AND METHODS: Twenty-eight patients who underwent [18F]FDG PET/CT scans before and at first restaging therapy with immuno-checkpoint inhibitors (ICIs) were retrospectively analyzed. PET-based semi-quantitative parameters extracted from both scans were respectively: SUVmax and SUVpeak of the target lesion, whole-body metabolic tumor volume (MTVWB), and whole-body total lesion glycolysis (TLGWB), as well as their interval changes (ΔSUVmaxTL, ΔSUVpeakTL, ΔMTVWB, ΔTLGWB). These PET-derived parameters were correlated to controlled disease (CD) assessed by RECIST 1.1. IrAEs, if present, were also described and correlated with clinical benefit (CB). SUVmax of the spleen and bone marrow at restaging scans were also correlated to CB. RESULTS: The CD was achieved in 54% of patients. Out of 28 eligible patients, 13 (46%) experienced progressive disease (PD), 7 showed SD, 7 had PR, and only in one patient CR was achieved. ΔSUVmaxTL (p = 0.002) and ΔSUVpeakTL (p < 0.001) as well as ΔMTVWB (p < 0.001) and ΔTLGWB (p < 0.005) were significantly associated with PD vs. non-PD. IrAEs and lymphoid cell-rich organs activation did not correlate with CB. CONCLUSIONS: [18F]FDG PET/CT by using interval changes of PET-derived semi-quantitative parameters could represent a reliable tool in immunotherapy treatment response evaluation in NSCLC patients.

Usefulness of 18F-FDG PET/CT in Patients with Cardiac Implantable Electronic Device Suspected of Late Infection.

The presence of a cardiovascular implantable electronic device (CIED) can be burdened by complications such as late infections that are associated with significant morbidity and mortality and require immediate and effective treatment. The aim of this study was to evaluate the role of 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (18F-FDG PET/CT) in patients with suspected CIED infection. Fifteen patients who performed a 18F-FDG PET/CT for suspicion of CIED infection were retrospectively analyzed; 15 patients, with CIED, that underwent 18F-FDG PET/CT for oncological reasons, were also evaluated. Visual qualitative analysis and semi-quantitative analysis were performed. All patients underwent standard clinical management regardless 18F-FDG PET/CT results. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) resulted as 90.91%, 75%, 86.67%, 90.91% and 75% respectively. Maximum standardized uptake values (SUVmax) and semi-quantitative ratio (SQR) were collected and showed differences statistically significant between CIED infected patients and those who were not. Exploratory cut-off values were derived from receiver operating characteristic (ROC) curves for SUVmax (2.56) and SQR (4.15). This study suggests the clinical usefulness of 18F-FDG PET/CT in patients with CIED infection due to its high sensitivity, repeatability and non-invasiveness. It can help the clinicians in decision making, especially in patients with doubtful clinical presentation. Future large-scale and multicentric studies should be conducted to establish precise protocols about 18F-FDG PET/CT performance.

[Role of 18F-FDG PET/CT in comparison with CECT for whole-body assessment of patients with esophageal cancer.] / Il ruolo della 18F-FDG PET/CT nella stadiazione dei pazienti con carcinoma esofageo.

AIM: We aimed to evaluate the role of 18F-FDG PET/CT in the TNM staging of esophageal cancer in comparison with contrast-enhancement computed-tomography (CECT). Futhermore we set out to determine the role of semiquantitative PET parameters. METHODS: 55 patients performed 18F-FDG PET/CT and CECT. Values of Sensitivity (Se), specificity (Sp), accuracy and predictability (PPV and NPV) were evaluated. McNemar test was applied for comparison. Cohen's K was calculated to measure the agreement. 18F-FDG PET/CT semiquantitative parameters (SUVmax, SUVmean, MTV and TLG) in relation to site and histotype, were assessed by ANOVA test and post-hoc test. RESULTS: About T parameter, Se, Sp, accuracy, PPV and NPV of CECT and 18F-FDG PET/CT were respectively 82.35%, 94.48%, 85.00%, 93.33% and 76% for both the tecniques; the agreement resulted substantial. There were no statistically significant relationships between 18F-FDG PET/CT parameters and sites; MTV value differs in histotypes. About N parameter, Se, Sp, accuracy, PPV and NPV of CECT were respectively 82.35%, 57.89%, 65.00%, 46.67%, 88%; for 18F-FDG PET/CT were 88.23%, 60.53%, 61%, 50% and 92%; the agreement resulted fair. About M parameter, Se, Sp, accuracy, PPV and NPV PET/CT were equal for both techniques: 76.92%, 52.38%, 58.33%, 33%, 88%; the agreement resulted moderate. No statistical difference was observed in any comparison. CONCLUSION: 18F-FDG PET/CT is a useful tool for whole-body evaluation of patients with esophageal cancer, allowing an effective clinical TNM staging. In particular 18F-FDG PET/CT's ability in detecting distant metastases suggest its routinary performance as a second level of investigation.

Pediatric Hodgkin Lymphoma: Predictive value of interim 18F-FDG PET/CT in therapy response assessment.

We investigated the prognostic value of interim F-FDG PET/CT (PET-2) in pediatric Hodgkin lymphoma (pHL), evaluating both visual and semiquantitative analysis.Thirty pHL patients (age ≤16) underwent serial F-FDG PET/CT: at baseline (PET-0), after 2 cycles of chemotherapy (PET-2) and at the end of first-line chemotherapy (PET-T). PET response assessment was carried out visually according to the Deauville Score (DS), as well as semiquantitatively by using the semiquantitative parameters reduction from PET-0 to PET-2 (ΔΣSUVmax0-2, ΔΣSUVmean0-2). Final clinical response assessment (outcome) at the end of first-line chemotherapy was the criterion standard, considering patients as responders (R) or nonresponders (NR). Disease status was followed identifying patients with absence or relapsed/progression disease (mean follow-up: 24 months, range 3-78).Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of visual and semiquantitative assessment were calculated; furthermore, Fisher exact test was performed to evaluate the association between both visual and semiquantitative assessment and outcome at the end of the first-line chemotherapy. The prognostic capability of PET-2 semiquantitative parameters was calculated by ROC analysis and expressed as area under curve (AUC). Finally, progression-free survival (PFS) was analyzed according to PET-2 results based on the 5-point scale and semiquantitative criteria, using the Kaplan-Meier method.Based on the outcome at the end of first-line chemotherapy, 5 of 30 patients were NR, the remnant 25 of 30 were R. Sensitivity, specificity, PPV, NPV, and accuracy of visual analysis were 60%,72%,30%,90%,70%; conversely, sensitivity, specificity, PPV, NPV, and accuracy of semiquantitative assessment were 80%, 92%, 66.7%, 95.8%, 90%. The highest AUC resulted for ΔΣSUVmax0-2 (0.836; cut-off <12.5; sensitivity 80%; specificity 91%). The association between ΔΣSUVmax0-2 and outcome at the end of first-line chemotherapy resulted to have a strong statistical significance (P = 0.0026). Both methods demonstrated to influence PFS, even if the semiquantitative assessment allowed a more accurate identification of patients with a high risk of treatment failure (P = 0.005).Our preliminary results showed that PET-2 visual assessment, by using Deauville criteria, can be improved by using the semiquantitative analysis. The SUV max reduction (ΔΣSUVmax0-2) evaluation might provide a support for the interpretation of intermediate scores, predicting with good confidence those patients who will have a poor outcome and require alternative therapies.

[18F-FDG PET/CT in ocular and orbital abnormalities not only neopastic: comparison with traditional imaging]. / La 18F-FDG PET/CT nello studio delle lesioni orbitarie e oculari neoplastiche e non: comparazione con l'imaging tradizionale.

UNLABELLED: Orbital and ocular neoplasms are rare tumors that could be benign or malign, primary or metastatic. Abnormalities within the orbit present a challenge in evaluation for imaging, both for morphologic examinations (ME) as weel as computed tomography (CT) and magnetic resonance (MR) and [18F]-2-deoxy-D-glucose Positron emission tomography/computed tomography (18F-FDG PET/CT). The aim of our study was evaluate 18F-FDG PET/CT role in orbital abnormalities, comparing it with CT and MR. MATERIALS AND METHODS: A retrospective analysis of 67 patients (pts) (34 males and 33 females; mean age 59.91 years old) who performed 18F-FDG PET/CT for orbital and ocular abnormalities was performed. Comparison between 18F-FDG PET/CT and ME was performed by Cohen's K also within the most representative hystologic subtypes. RESULTS: 18F-FDG PET/CT resulted positive in 19/67 pts. 47/67 pts performed ME (27/47 performed CT and 20/27 MR) within 20 days before 18F-FDG PET/CT and concordance was very poor (K=0.154). Considering 27/47 pts who performed CT, concordance was very poor (K=0.100). Considering the 20/47 pts who performed MR concordance was poor (K=0.266). Considering 19/47 pts with primary ocular NHL concordance resulted poor (K=0.269). Considering 6/47 pts with primary ocular melanoma concordance resulted very poor (K=0.182). In 9/47 pts with metastases diagnosis, concordance was absent (K=-0.189). CONCLUSIONS: CT and MR are ME that permit the evaluation of the orbital region even with limits related to the difficulties of the region. 18F-FDG PET/CT is a sensitive tecnique for several malignancies. The low concordance among 18F-FDG PET/CT and ME suggests their complementary role, then to associate 18F-FDG PET/CT even for the whole-body evaluation.

18F-FDGPET/CT: diabetes and hyperglycaemia.

BACKGROUND: Some patients who undergo 18F-FDG PET/CTfor neoplastic or benign disease are also affected by diabetes or hyperglycaemia. We propose different preparation procedures inpatients (pts) with hyperglycaemia (acute, temporary or chronic)or diabetes (type 1 or 2) at the time of the 18F-FDG injection, in order to improve the diagnostic scheduling of 18F-FDG PET/CT. MATERIAL AND METHODS: We evaluated a sample of 13,063 pts, examined in two different PET/CT centres, one with a stationary scanner (94.4%) and the other with a mobile device (5.6%). High blood sugar was present in 1,698 patients (13%) at the time of the 18F-FDG injection (hyperglycaemia was defined as fasting blood glucose > 11.1 mmol/l). We considered all 18F-FDG PET/CT tests performed over a period of 4 years (2006-2009). In the first 2 years (6,236 tests), scheduling was done directly by the administrative secretary. In the next two years, 6,827 pts underwent a preliminary visit to assess the test indications, medical history, and therapy as well as pre-test preparation. We evaluated different preparation protocols for hyperglycaemic or diabetic pts, especially those recommended in the guidelines of the European Association of Nuclear Medicine (EANM) and Society of Nuclear Medicine (SNM). RESULTS: In the four-year period, 713/13,063 patients (5.45%)were rescheduled; of these, 78.8% were rescheduled in the two years before the implementation of our preparation protocols and 21.2% in the next two years.Before the implementation of our preparation protocols, 562 patients (9%) presented occasional, acute or chronic hyperglycaemia (56.7%), or diabetes (43.3%), requiring postponement of the test to a later date. The test was not performed in 17 of 6,236 pts (0.27%) because of blood glucose levels above 11.1 mmol/l for several days, while in 16/6236 pts (0.26%) the18F-FDG injection was performed despite high blood glucose levels, in view of the clinical urgency.After the implementation of the preparation protocols, 2.2% of pts were rescheduled because of occasional, acute or chronic hyperglycaemia (79%), or diabetes (21%); 0.1% of pts did not undergo the test because of chronic high blood glucose levels. Although the administration of insulin is recommended in theEANM and SNM guidelines, in our new preparation procedures experience it was not necessary, because we reduced the numbers of hyperglycaemic pts thanks to screening at the preliminary visit and a subsequent good preparation of the patient before scheduling. CONCLUSIONS: The application of our preparation protocols improves the on-time performance and diagnostic accuracy,and increases patients' compliance.

18F-FDG PET/CT in suspected recurrences of epithelial malignant pleural mesothelioma in asbestos-fibers-exposed patients (comparison to standard diagnostic follow-up).

This retrospective study evaluated the role of 18-fluorine-labeled 2-deoxy-2-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with previous occupational or environmental exposure to asbestos, with histopathological diagnosis of epithelial malignant pleural mesothelioma and suspected recurrences, comparing the data from 18F-FDG PET/CT and computed tomography with contrast enhancement (CECT). 18F-FDG PET/CT has greater sensitivity than CECT in identifying local extent, lymph nodes, and metastasis. 18F-FDG PET/CT whole-body explorations are useful to monitor the follow-up and evaluate the metabolic response to chemo- and radiotherapy, modifying the scheduled treatment plan.

A retrospective study comparing contrast-enhanced computed tomography with 18F-FDG-PET/CT in the early follow-up of patients with retroperitoneal sarcomas.

OBJECTIVE: To compare 18-fluorine-labeled 2-deoxy-2-fluoro-D-glucose PET/computed tomography ((18)F-FDG-PET/CT) with contrast enhancement computed tomography (CECT) in the early follow-up of patients who had undergone treatment for primitive retroperitoneal sarcomas (RS). METHODS: This is a retrospective study on 24 patients who underwent (18)F-FDG-PET/CT and CECT within 2 years after therapy for RS. (18)F-FDG-PET/CT and CECT results were compared with results of histological examination and clinical-instrumental follow-up. We calculated the sensitivity and specificity of CECT and (18)F-FDG-PET/CT for retroperitoneal recurrences and compared them with results of the McNemar test. Negative predictive values (NPVs) and positive predictive values (PPVs) were calculated and the positive percentage agreement and negative percentage agreement were evaluated. RESULTS: The sensitivity and specificity of (18)F-FDG-PET/CT were 66.7 and 100% and those for CECT were 58.3 and 50%, respectively. For (18)F-FDG-PET/CT, PPV was 100% [95% confidence interval (CI): 67-100%] and NPV was 75% (95% CI: 58-75%); for CECT, PPV was 54% (95% CI: 33-73%) and NPV was 55% (95% CI: 30-78%). Positive percentage agreement and negative percentage agreement were, respectively, 38 and 72% for retroperitoneal lesions, 42.8 and 100% for liposarcomas, 40 and 50% for leiomyosarcomas, 14.2 and 94% for abdominal lymph nodes, and 16.6 and 100% for lung metastasis. Neither technique gave reliable results for liver metastasis. CONCLUSION: Our data show that (18)F-FDG-PET/CT has a higher overall specificity compared with CECT in identifying areas of recurrence, demonstrating its validity for early whole-body detection of lesions. In our hands (18)F-FDG-PET/CT seems to be a good tool in the early follow-up of patients experiencing recurrence of RS.