Treatment of giant cell arteritis with ultra-short glucocorticoids and tocilizumab: the role of imaging in a prospective observational study.

OBJECTIVES: To assess the impact of tocilizumab (TCZ) monotherapy after ultra-short-pulse glucocorticoids (GCs) on clinical manifestations, and vessel inflammation and damage in large vessel-GCA (LV-GCA). METHODS: In this prospective observational study, we enrolled patients with active LV-GCA. All patients received 500 mg per day i.v. methylprednisolone for three consecutive days and weekly s.c. TCZ injections from day 4 until week 52. PET/CT was performed on all patients at baseline and at weeks 24 and 52. The primary end points were the reduction in the PET vascular activity score (PETVAS) at weeks 24 and 52 compared with baseline, and the proportion of patients with relapse-free remission at weeks 24 and 52. The secondary end point was the proportion of patients with new aortic dilation at weeks 24 and 52. RESULTS: A total of 18 patients were included (72% female, mean age 68.5 years). Compared with the baseline value, a significant reduction in the PETVAS was observed at weeks 24 and 52, mean (95% CI) reductions -8.6 (-11.5 to -5.7) and -10.4 (-13.6 to -7.2), P = 0.001 and 0.002, respectively. The proportion of patients with relapse-free remission at weeks 24 and 52 was 10/18 (56%, 95% CI 31-78) and 8/17 (47%, 95% CI 23-72), respectively. At weeks 24 and 52, no patient had shown new aortic dilation. However, 4 patients who had shown aortic dilation at baseline showed a significant increase in aortic diameter (≥5 mm) at week 52. CONCLUSION: TCZ monotherapy after ultra-short-pulse GCs controlled the clinical symptoms of GCA and reduced vascular inflammation. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT05394909.

The role of PET/CT in disease activity assessment in patients with large vessel vasculitis.

OBJECTIVES: To evaluate the accuracy of PET/CT and of PET vascular activity score (PETVAS) in assessing disease activity and the ability of PETVAS in predicting relapses in a large single-centre cohort of patients with large vessel vasculitis (LVV). METHODS: We conducted a retrospective cohort study of prospectively collected data of consecutive patients diagnosed with LVV who underwent at least one PET/CT scan between 2007 and 2020. The nuclear medicine physician's interpretation of each PET/CT scan (active/inactive vasculitis) was compared with disease activity clinical judgement (active disease/remission). For each PET/CT scan, the PETVAS score was calculated and its accuracy in assessing disease activity was evaluated. The ability of PETVAS in predicting subsequent relapses was evaluated. RESULTS: A total of 100 consecutive LVV patients (51 large vessel GCA, 49 Takayasu arteritis) underwent a total of 476 PET/CT scans over a mean follow-up period of 97.5 months. Physician-determined PET/CT grading was able to distinguish between clinically active and inactive LVV with a sensitivity of 60% (95% CI 50.9, 68.7) and specificity of 80.1% (95% CI 75.5, 84.1); the area under the curve (AUC )was 0.70 (95% CI 0.65, 0.75). PETVAS was associated with disease activity, with an age and sex-adjusted odds ratio for active disease of 1.15 (95% CI 1.11, 1.19). A PETVAS ≥10 provided 60.8% sensitivity and 80.6% specificity in differentiating between clinically active and inactive LVV; the AUC was 0.73 (95% CI 0.68, 0.79). PETVAS was not associated with subsequent relapses, with an age and sex-adjusted hazard ratio of 1.04 (95% CI 0.97, 1.11). CONCLUSIONS: The visual PET/CT grading scale and PETVAS had moderate accuracy to distinguish active LVV from remission. PETVAS did not predict disease relapses.

Resolution of vascular inflammation in patients with new-onset giant cell arteritis: data from the RIGA study.

OBJECTIVES: Efficacy evaluation of GCA treatment is primarily based on non-specific symptoms and laboratory markers. We aimed to assess the change in vascular inflammation in patients with large vessel (LV)-GCA under different treatments using [18F]FDG PET/CT. METHODS: Observational study on patients with new-onset, active LV-GCA starting treatment with either prednisolone monotherapy (PRED) or combination with MTX or tocilizumab (TOC). All patients underwent baseline and follow-up PET/CT. The aorta and its major branches were assessed using PET vascular activity score (PETVAS) by independent readers. Cumulative glucocorticoid doses and cessation of glucocorticoid treatment were documented in all patients. RESULTS: We included 88 LV-GCA patients, 27 were treated with PRED, 42 with MTX and 19 with TOC. PETVAS decreased from 18.9-8.0 units at follow-up in the overall population (P <0.001). PETVAS changes were numerically higher in patients receiving MTX (-12.3 units) or TOC (-11.7 units) compared with PRED (-8.7). Mean cumulative prednisolone dosages were 5637, 4418 and 2984 mg in patients treated with PRED, MTX and TOC (P =0.002). Risk ratios for glucocorticoid discontinuation at the time of follow-up PET/CT were 6.77 (95% CI: 1.01, 45.29; P =0.049) and 16.25 (95% CI: 2.60, 101.73; P =0.003) for MTX and TOC users compared with PRED users. CONCLUSION: Treatment of LV-GCA inhibits vascular inflammation in the aorta and its major branches. While similar control of vascular inflammation was achieved with PRED, MTX and TOC treatments, TOC showed a strong glucocorticoid sparing effect, supporting the concept of initial combination therapy.

Imbalance between angiogenic and anti-angiogenic factors in sera from patients with large-vessel vasculitis.

OBJECTIVES: To investigate serum levels of a panel of angiogenic inducers (VEGF, FGF-2, Angiopoietin 1, -2, soluble VCAM-1) and inhibitors (angiostatin, endostatin, pentraxin-3) in patients with giant cell arteritis (GCA) and Takayasu's arteritis (TAK), in order to gain further insights into the molecular mechanisms driving angiogenesis dysregulation in large-vessel vasculitis (LVV). METHODS: Sera were obtained from 33 TAK patients and 14 GCA patients and from two groups of age-matched normal controls (NC). Disease activity was assessed using 18F-FDG PET/CT and clinical indices including NIH/Kerr criteria and ITAS. Angiogenic and anti-angiogenic factor serum levels were evaluated using commercial ELISA kits. Pentraxin 3 (PTX3) serum levels were evaluated by non-commercial ELISA, as already described. RESULTS: Among the angiogenic factors, only VEGF serum levels were significantly higher in TAK patients compared to NC. No difference was found between angiogenic factor levels in GCA patients compared to those detected in NC. Anti-angiogenic factor (Angiostatin, Endostatin, PTX3) serum levels were significantly higher in both GCA and TAK patients compared to NC. Significant associations were observed between VEGF and PTX3 levels and disease activity evaluated using PET scan and clinical indices. Cluster analysis based on PET scan scores in TAK patients showed significant ordered differences in VEGF and angiostatin serum levels. Indeed, we noted a progressive increase of VEGF and angiostatin from NC to the cluster including patients with the highest and more diffuse scan positivity. CONCLUSIONS: Our overall results demonstrate a circulating molecular profile characterised by a prevailing expression of anti-angiogenic soluble factors.

Molecular Imaging of Pulmonary Inflammation and Infection.

Infectious and inflammatory pulmonary diseases are a leading cause of morbidity and mortality worldwide. Although infrequently used in this setting, molecular imaging may significantly contribute to their diagnosis using techniques like single photon emission tomography (SPET), positron emission tomography (PET) with computed tomography (CT) or magnetic resonance imaging (MRI) with the support of specific or unspecific radiopharmaceutical agents. 18F-Fluorodeoxyglucose (18F-FDG), mostly applied in oncological imaging, can also detect cells actively involved in infectious and inflammatory conditions, even if with a low specificity. SPET with nonspecific (e.g., 67Gallium-citrate (67Ga citrate)) and specific tracers (e.g., white blood cells radiolabeled with 111Indium-oxine (111In) or 99mTechnetium (99mTc)) showed interesting results for many inflammatory lung diseases. However, 67Ga citrate is unfavorable by a radioprotection point of view while radiolabeled white blood cells scan implies complex laboratory settings and labeling procedures. Radiolabeled antibiotics (e.g., ciprofloxacin) have been recently tested, although they seem to be quite unspecific and cause antibiotic resistance. New radiolabeled agents like antimicrobic peptides, binding to bacterial cell membranes, seem very promising. Thus, the aim of this narrative review is to provide a comprehensive overview about techniques, including PET/MRI, and tracers that can guide the clinicians in the appropriate diagnostic pathway of infectious and inflammatory pulmonary diseases.

Use of imaging techniques in large vessel vasculitis and related conditions.

Giant cell arteritis (GCA) and Takayasu's arteritis (TA) are large vessel vasculitis (LVV) primarily affecting the aorta and its major branches, mainly differentiated by the onset age (>50 years GCA and <40 years TA). In addition, temporal artery involvement and polymyalgia rheumatica are typical features of GCA, but not TA. Imaging techniques are required to secure the diagnosis of large-vessel vasculitides, and to monitor the disease course. Both morphological and metabolic imaging are involved. Morphological imaging is represented mainly by computerized tomography (CT), CT angiography, magnetic resonance (MR), MR angiography, color-Doppler sonography (CDS) and high-resolution CDS. Metabolic aspects of inflammatory process in LVV can be well studied by positron emission tomography/computed tomography with [18F]deoxyglucose ([18F]FDG PET/CT). It has an important increasing role in diagnosis, extent assessment and disease activity and therapy response evaluation. In the near future the concomitant development of increasingly powerful PET/CT scanners, of new radiopharmaceuticals more specific for inflammation, and of new PET/MRI hybrid scanners probably will lead to a further new step forward in the diagnosis and clinical management of LVV.

Distribution patterns of 18F-fluorodeoxyglucose in large vessels of Takayasu's and giant cell arteritis using positron emission tomography.

OBJECTIVES: To compare patterns of vascular involvement using 18F-fluorodeoxyglucose-positron emission tomography computed tomography (FDG PET/CT) in patients with giant cell arteritis (GCA) and Takayasu's arteritis (TAK). METHODS: A total of 130 consecutive 18F-FDG PET/CT scans performed during the disease course for evaluating disease activity in 15 GCA and 13 TAK patients were retrospectively examined by two nuclear physicians blinded to clinical data. Standardised uptake values (SUVmax) in 14 vascular districts including all the aortic segments and the main tributaries were measured. The average SUVmax value for each vascular district was also calculated. Principal component analysis (PCA) and agglomerative hierarchical cluster analysis (CA) were used to explore distribution patterns of vascular FDG uptake. RESULTS: The aortic segments showed the highest SUV max values among the different districts in both GCA and TAK. SUV max values measured in the different districts were significantly higher in GCA compared to TAK, except for the axillary arteries. Regarding thoracic and abdominal aorta, ascending aorta and aortic arch had the highest correlation in both vasculitis (p<0.0001). CA confirmed that carotid, axillary, subclavian, iliac and femoral arteries clustered with their contralateral counterpart in both vasculitis. The 3 components of thoracic aorta clustered with abdominal aorta in TAK, while aortic arch clustered only with ascending aorta, and descending and abdominal aorta grouped together with iliac and femoral arteries in GCA. PCA analysis identified 3 different components for TAK and GCA explaining 72% and 71% of the total variance respectively in these two vasculitis. Confirming CA, a component including the entire aortic district was identified in TAK, but not in GCA. Similar results in PCA using averaged data were observed. CONCLUSIONS: Strong similarities, but also a subtle skewing in terms of distribution patterns of arterial involvement assessed by SUVmax values were observed between GCA and TAK.

Interleukin-6 and soluble interleukin-6 receptor are elevated in large-vessel vasculitis: a cross-sectional and longitudinal study.

OBJECTIVES: To investigate serum levels of IL- 6 and soluble IL-6 receptor (sIL-6R) in patients with large-vessel vasculitis and their relationship with disease activity. METHODS: Sera were obtained from 33 Takayasu's arteritis (TAK) patients and 14 giant cell arteritis (GCA) patients, and from 60 age-matched normal controls (NCs). Disease activity was assessed using 18F-FDG PET/CT and clinical indices including NIH/Kerr criteria and ITAS. Among TAK patients with active disease at baseline, clinical records and serum samples from 11 TAK patients were available for the longitudinal study. IL-6 and sIL-6R serum levels were evaluated using commercial ELISA kits. RESULTS: IL-6 and sIL-6R serum levels were significantly higher in both GCA and TAK patients compared to NCs. IL-6 levels in TAK patients were significantly increased irrespective of disease phase, while a significant increase in sIL-6R concentrations was only found in TAK patients with active disease. Conversely, in GCA, IL-6 levels were significantly raised only in patients with active diseases, whereas sIL-6R levels appeared to be significantly higher irrespective of disease activity. Longitudinal analysis showed that levels of sIL-6R in TAK patients were significantly higher only at baseline, compared to NCs, whereas IL-6 levels were found to be significantly increased at each follow-up time point. CONCLUSIONS: These overall results might suggest a role for sIL-6R as a potential biomarker for disease activity in TAK patients, whereas in GCA, modifications of IL-6 might better identify patients with active disease.

PET and PET/CT with 68gallium-labeled somatostatin analogues in Non GEP-NETs Tumors.

Somatostatin (SST) is a 28-amino-acid cyclic neuropeptide mainly secreted by neurons and endocrine cells. A major interest for SST receptors (SSTR) as target for in vivo diagnostic and therapeutic purposes was born since a series of stable synthetic SST-analouges PET became available, being the native somatostatin non feasible for clinical use due to the very low metabolic stability. The rationale for the employment of SST-analogues to image cancer is both based on the expression of SSTR by tumor and on the high affinity of these compounds for SSTR. The primary indication of SST-analogues imaging is for neuroendocrine tumors (NETs), which usually express a high density of SSTR, so they can be effectively targeted and visualized with radiolabeled SST-analogues in vivo. Particularly, SST-analogues imaging has been widely employed in gastroenteropancreatic (GEP) NETs. Nevertheless, a variety of tumors other than NETs expresses SSTR thus SST-analogues imaging can also be used in these tumors, particularly if treatment with radiolabeled therapeutic SST-analouges PET is being considered. The aim of this paper is to provide a concise overview of the role of positron emission tomography/computed tomography (PET/CT) with (68)Ga-radiolabeled SST-analouges PET in tumors other than GEP-NETs.

Takayasu arteritis and large-vessel giant cell arteritis in Italian population. Comprehensive analysis from a single institutional cohort of 184 cases.

OBJECTIVE: To compare clinical and imaging characteristics in patients with Takayasu arteritis (TAK) and large vessel-giant cell arteritis (LV-GCA) in an Italian population. METHODS: We conducted a retrospective monocenter study comparing characteristics and outcomes of a cohort of 59 patients with TAK and a cohort of 127 patients with LV-GCA diagnosed between 1996 and 2016. Most of them (92%) were followed up for at least 24 months at Reggio Emilia Hospital (Italy). We also reviewed the literature discussing the results of the published manuscripts comparing LV-GCA to TAK RESULTS: LV-GCA patients had a higher prevalence of males (p = 0.003), and more frequently presented with cranial symptoms (p = 0.001), fever ≥38 °C (p = 0.007), polymyalgia rheumatica (p = 0.001), and hypertension (p = 0.001), and they had higher ESR levels at diagnosis (p = 0.0001). Differently, TAK patients had longer delay to diagnosis from the beginning of symptoms (p = 0.048), they presented more frequently with loss of pulses of large arteries (p = 0.0001), vascular bruits (p = 0.001), limb claudication (p = 0.003), myocardial infarction/angina (p = 0.03), and hypertension induced by renal artery stenosis (p = 0.001). Regarding treatment, TAK patients received a higher total and at 1 year cumulative prednisone doses (p = 0.0001 and p = 0.001, respectively), they had a longer duration of prednisone therapy (p = 0.008), and received during follow-up more frequently traditional immunosuppressants (p = 0.0001) and biological agents (p = 0.0001). Flares were more frequently observed in TAK patient (p = 0.001), while no differences were observed for long-term remission. New vascular procedures during the follow-up were more frequently performed in TAK patients (p = 0.0001). Regarding imaging at diagnosis, TAK patients had more frequently vascular stenosis/occlusion (p = 0.0001) and a higher number of vessels with structural damage per person (p = 0.0001), while LV-GCA patients had a higher number of inflamed vessels per person (p = 0.0001). Comparing the involved vascular districts at diagnosis for the presence of vessel inflammation and/or arterial damage, patients with LV-GCA had a more frequent involvement of thoracic and abdominal aorta (p = 0.024 and p = 0.007, respectively), and axillary, iliac and femoral arteries (p = 0.018, p = 0.002, and p = 0.0001. respectively), while in TAK patients, brachiocephalic, celiac, mesenteric and renal arteries were more frequently involved (p = 0.011, p = 0.019, p = 0.019, and p = 0.005, respectively). At imaging arterial damage at diagnosis was more frequently observed in TAK patients, specifically at common carotid, brachiocephalic, and subclavian arteries (p = 0.0001, p = 0.006, p = 0.0001, respectively) and descending aorta (p = 0.022). Regarding imaging during the follow-up, TAK patients developed more frequently new vascular stenosis/occlusion (p = 0.0001) and new vascular thickening (p = 0.002), no differences were observed for the development of new dilatation/aneurysm between the two vasculitides. CONCLUSION: Patients with TAK and LV-GCA show a number of similarities and also differences. Indeed, it is unclear whether they are part of the same disease spectrum or they are different conditions. As more information regarding the pathogenesis and etiology becomes known, answers to these questions are like to be forthcoming.

Quantitative dopamine transporter imaging assessment in Parkinson's disease patients carrying GBA gene mutations compared with idiopathic PD patients: A case-control study.

BACKGROUND: Genetic risk factors impact around 15% of Parkinson's disease (PD) patients and at least 23 variants have been identified including Glucocerebrosidase (GBA) gene variants. Using different clinical and instrumental qualitative-based data, various studies have been published on GBA-PD cohorts which suggested possible differences in dopaminergic nigrostriatal denervation pattern, particularly in caudate and putamen nuclei. METHODS: This retrospective study included two consecutive homogenous cohorts of GBA-PD and idiopathic (I-PD) patients. Each consecutive GBA-PD patient has been matched with a 1:1 pairing method with a consecutive I-PD subject according to age, age at disease onset, sex, Hoehn & Yahr (H&Y) staging scale and comorbidity level (CCI). Semiquantitative volumetric data by the DaTQUANTTM software integrated in the DaTSCAN exam performed at time of the diagnosis (SPECT imaging performed according to current guidelines of I-123 FPCIT SPECT imaging) were extrapolated. Bilateral specific binding ratios (SBR) at putamen and caudate levels were calculated, using the occipital lobes uptake. The Mann-Whitney test was performed to compare the two cohorts while the Spearman's test was used to find correlations between motor and volumetric data in each group. Bonferroni correction was used to account for multiple comparisons. RESULTS: Two cohorts of 25 patients each (GBA-PD and I-PD), were included. By comparing GBA-PD and I-PD patients, lower SBR values were found in the most affected anterior putamen and left caudate of the GBA-PD cohort. Furthermore, in the GBA-PD cohort the SBR of the most affected posterior putamen negatively correlated with the H&Y scale. However, none of these differences or correlations remained significant after Bonferroni correction for multiple comparisons. CONCLUSIONS: We observed differences in SBR values in GBA-PD patients compared with I-PD. However, these differences were no longer significant after Bonferroni multiple comparisons correction highlighting the need for larger, longitudinal studies.

Vessel inflammation and morphological changes in patients with large vessel vasculitis: a retrospective study.

OBJECTIVE: The aim was to identify any association between imaging signs of vessel wall inflammation (positron emission tomography-CT (PET-CT) score and CT/MR wall thickening) and synchronous and subsequent vascular damage (stenoses/dilations) in patients with large vessel vasculitis (LVV). METHODS: Consecutive patients with LVV referred to a tertiary centre in 2007-2020 with baseline PET-CT and morphological imaging (CT/MR angiography) performed within 3 months were included. All available PET-CT and CT/MR scans were reviewed to assess PET-CT uptake (4-point semi-quantitative score), wall thickening, stenoses and dilations for 15 vascular segments. The associations of baseline PET score and CT/MR wall thickening with synchronous and incident stenoses/dilations at CT/MR performed 6-30 months from baseline were evaluated in per-segment and per-patient analyses. Respective areas under the receiver operating characteristic curve (AUC) were calculated. RESULTS: We included 100 patients with LVV (median age: 48 years, 22% males). Baseline PET score and wall thickening were strongly associated (Cuzick non-parametric test for trend across order groups (NPtrend) <0.001). The association with synchronous stenoses/dilations was weak for PET score (NPtrend=0.01) and strong for wall thickening (p<0.001). In per-patient analyses, sensitivity/specificity for ≥1 synchronous stenoses/dilations were 44%/67% for PET score ≥2 and 66.7%/60.5% for wall thickening. Subsequent CTs/MRs were available in 28 patients, with seven incident stenoses/dilations. Baseline PET score was strongly associated with incident stenoses/dilations (p=0.001), while baseline wall thickening was not (p=0.708), with AUCs for incident stenoses/dilations of 0.80 for PET score and 0.52 for wall thickening. CONCLUSION: PET score and wall thickening are strongly associated, but only baseline PET score is a good predictor of incident vessel wall damage in LVV.

An easy and practical guide for imaging infection/inflammation by [18F]FDG PET/CT.

AIM: The aim of this mini-review was to summarize the role of positron emission tomography/computed tomography (PET/CT) with 18Fluorine-fluorodeoxyglucose ([18F]FDG) in inflammatory and infective processes, based on the published scientific evidence. METHODS: We analysed clinical indications, patient preparation, image acquisition protocols, image interpretation, pitfalls and how to make the report of cardio-vascular diseases, musculoskeletal diseases and other inflammatory and infective systemic diseases.Results of this analysis are shown in practical tables, easy to understand for daily routine consultation. CONCLUSIONS: Despite [18F]FDG is currently used in several inflammatory and infective diseases, standardized interpretation criteria are still needed in most cases. It is, therefore, foreseen the execution of multicentre clinical studies that, by adopting the same acquisition and interpretation criteria, may contribute to the standardization of this imaging modality.

Prognostic Impact of Muscle Quantity and Quality and Fat Distribution in Diffuse Large B-Cell Lymphoma Patients.

Baseline CT scans of 116 patients (48% female, median 64 years) with diffuse large B-cell lymphoma (DLBCL) were retrospectively reviewed to investigate the prognostic role of sarcopenia and fat compartment distributions on overall survival (OS), progression-free survival (PFS), and early therapy termination. Skeletal muscle index (SMI), skeletal muscle density (SMD), and intermuscular adipose tissue (IMAT) were quantified at the level of the third lumbar vertebra (L3) and proximal thigh (PT). Low L3-SMD, but not low L3-SMI, was associated with early therapy termination (p = 0.028), shorter OS (HR = 6.29; 95% CI = 2.17-18.26; p < 0.001), and shorter PFS (HR = 2.42; 95% CI = 1.26-4.65; p = 0.008). After correction for sex, International Prognostic Index (IPI), BMI, and R-CHOP therapy (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), low L3-SMD remained associated with poor OS (HR = 3.54; 95% CI = 1.10-11.40; p = 0.034) but not with PFS. Increased PT-IMAT was prognostic for poor OS and PFS after correction for sex, IPI, BMI, and R-CHOP therapy (HR = 1.35; CI = 1.03-1.7; p = 0.03, and HR = 1.30; CI = 1.04-1.64; p = 0.024, respectively). Reduced muscle quality (SMD) and increased intermuscular fat (IMAT), rather than low muscle quantity (SMI), are associated with poor prognosis in DLBCL, when measured at the L3 level, and particularly at the level of the proximal thigh. The proximal thigh represents a novel radiological landmark to study body composition.

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation.

AIM: The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [18F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections. METHODS: In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [18F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [18F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020. RESULTS: Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication. CONCLUSIONS: Currently, [18F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

Correlation of microvascular fractal dimension with positron emission tomography [(11)C]-methionine uptake in glioblastoma multiforme: preliminary findings.

Neuroradiological and metabolic imaging is a fundamental diagnostic procedure in the assessment of patients with primary and metastatic brain tumors. The correlation between objective parameters capable of quantifying the neoplastic angioarchitecture and imaging data may improve our understanding of the underlying physiopathology and make it possible to evaluate treatment efficacy in brain tumors. Only a few studies have so far correlated the quantitative parameters measuring the neovascularity of brain tumors with the metabolic profiles measured by means of amino acid uptake in positron emission tomography (PET) scans. Fractal geometry offers new mathematical tools for the description and quantification of complex anatomical systems, including microvascularity. In this study, we evaluated the microvascular network complexity of six cases of human glioblastoma multiforme quantifying the surface fractal dimension on CD34 immunostained specimens. The microvascular fractal dimension was estimated by applying the box-counting algorithm. As the fractal dimension depends on the density, size and shape of the vessels, and their distribution pattern, we defined it as an index of the whole complexity of microvascular architecture and compared it with the uptake of (11)C-methionine (MET) assessed by PET. The different fractal dimension values observed showed that the same histological category of brain tumor had different microvascular network architectures. Fractal dimension ranged between 1.19 and 1.77 (mean: 1.415+/-0.225), and the uptake of (11)C-methionine ranged between 1.30 and 5.30. A statistically significant direct correlation between the microvascular fractal dimension and the uptake of (11)C-methionine (p=0.02) was found. Our preliminary findings indicate that that vascularity (estimated on the histologic specimens by means of the fractal dimension) and (11)C-methionine uptake (assessed by PET) closely correlate in glioblastoma multiforme and that microvascular fractal dimension can be a useful parameter to objectively describe and quantify the geometrical complexity of the microangioarchitecture in glioblastoma multiforme.

Radiotherapy Planning and Molecular Imaging in Lung Cancer.

INTRODUCTION: In patients suitable for radical chemoradiotherapy for lung cancer, 18F-FDGPET/ CT is a proposed management to improve the accuracy of high dose radiotherapy. However, there is a high rate of locoregional failure in patients with locally advanced non-small cell lung cancer (NSCLC), probably due to the fact that standard dosing may not be effective in all patients. The aim of the present review was to address some criticisms associated with the radiotherapy image-guided in NSCLC. MATERIALS AND METHODS: A systematic literature search was conducted. Only published articles that met the following criteria were included: articles, only original papers, radiopharmaceutical ([18F]FDG and any tracer other than [18F]FDG), target, only specific for lung cancer radiotherapy planning, and experimental design (eventually "in vitro" studies were excluded). Peer-reviewed indexed journals, regardless of publication status (published, ahead of print, in press, etc.) were included. Reviews, case reports, abstracts, editorials, poster presentations, and publications in languages other than English were excluded. The decision to include or exclude an article was made by consensus and any disagreement was resolved through discussion. RESULTS: Hundred eligible full-text articles were assessed. Diverse information is now available in the literature about the role of FDG and new alternative radiopharmaceuticals for the planning of radiotherapy in NSCLC. In particular, the role of alternative technologies for the segmentation of FDG uptake is essential, although indeterminate for RT planning. The pros and cons of the available techniques have been extensively reported. CONCLUSION: PET/CT has a central place in the planning of radiotherapy for lung cancer and, in particular, for NSCLC assuming a substantial role in the delineation of tumor volume. The development of new radiopharmaceuticals can help overcome the problems related to the disadvantage of FDG to accumulate also in activated inflammatory cells, thus improving tumor characterization and providing new prognostic biomarkers.

Significance of inflammation restricted to adventitial/periadventitial tissue on temporal artery biopsy.

OBJECTIVE: To evaluate the characteristics and significance of inflammation restricted (RI) to the adventitial and/or periadventitial tissue on temporal artery biopsy (TAB). METHODS: We studied a retrospective cohort of 80 patients with RI, extending our earlier series of 39 patients. For comparison purposes, we collected the same data from 254 patients with transmural inflammation (TMI) and 81 TAB-negative patients. A review of the literature was also performed. RESULTS: A final diagnosis of giant cells arteritis (GCA) and/or polymyalgia rheumatica (PMR) was observed in 86% of patients with RI. Compared to TMI, GCA diagnosis was significantly less frequently observed in patients with RI and in those TAB-negative (p < 0.0001), while cranial manifestations were significantly less frequent (p = 0.001) and ESR and CRP values at diagnosis significantly reduced (p < 0.0001). PMR, permanent visual loss, and large vessel involvement at diagnosis were equally present in the 3 subgroups. The median duration of prednisone therapy, the cumulative prednisone dosages, and the relapse and long-term remission rates were similar between patients with GCA-RI and those with TMI. The positive likelihood ratios (LRs) of pathological evidence of RI at TAB for GCA or GCA/PMR diagnoses were 0.88 (CI, 0.61-1.27) and 1.15 (CI, 0.67-1.99), while that of inflammation limited to adventitia was 1.37 (CI, 0.59-3.19) and 3.77 (CI, 0.53-26.72). In the literature review, the positive LR of RI for GCA diagnosis was 0.92 (CI, 0.68-1.25). CONCLUSION: A large part of the patients with RI have GCA/PMR, however, the diagnostic value of RI for GCA diagnosis is not relevant.

Relapses and long-term remission in large vessel giant cell arteritis in northern Italy: Characteristics and predictors in a long-term follow-up study.

OBJECTIVE: To evaluate characteristics and predictors of relapses and long-term remission in an Italian cohort of patients with large-vessel (LV) giant cell arteritis (GCA). METHODS: We evaluated 87 consecutive patients with LV-GCA followed up at the Rheumatology Unit of Reggio Emilia Hospital (Italy) for at least 2 years. Patients with relapses and long-term remission were compared to those without. A group of 34 patients with biopsy proven GCA without LV vasculitis (LVV) at diagnosis was considered for comparison. PATIENTS: 37 patients (42.5%) experienced one or more relapses. Nineteen (37.2%) of the 51 relapses were experienced during the first year after diagnosis. The majority of relapses occurred with doses of prednisone (PDN) ≤ 10 mg/day (74.5%). Polymyalgia rheumatica (PMR) (41.2%) and worsening at imaging of LVV (39.2%) were the most frequently observed relapsing manifestations. The total cumulative prednisone dose was significantly higher (p < 0.0001) and the total duration of PDN treatment longer (p < 0.0001) in relapsing patients compared to those without relapses. Relapsing patients had at diagnosis more frequently fever ≥ 38°C (p = 0.03) and visual manifestations (p = 0.03), and less frequently long-term remission (p = 0.002). In the multivariate model fever ≥ 38°C (HR 2.30, 95%CI:1.11-4.78) and total cumulative PDN dose (HR 1.18, 95%CI: 1.08-1.30) were significantly associated with an increased risk of relapses, while aortic arch involvement at imaging at diagnosis (HR 0.26, 95%CI: 0.11-0.59) and long-term remission (HR 0.27, 95%CI: 0.11-0.65) with a reduced risk. 35/84 patients (41.6%) experienced long-term remission. PMR and disease relapses were less frequently observed (p = 0.04 and p = 0.002, respectively), and the total cumulative prednisone dose was lower (p < 0.001) in patients with long-term remission compared to those without. In the multivariate model the presence of relapses (HR 0.21, 95%CI: 0.07-0.62) and the total cumulative PDN dose (HR 0.85, 95%CI: 0.77-0.95) were significantly negatively associated with long-term remission. CONCLUSION: In our cohort of patients with LV GCA we identified predictors of a relapsing course and long-term remission, which were observed in around half of the patients.