Chest PET/MRI in Solid Cancers: Comparing the Diagnostic Performance of a Free-Breathing 3D-T1-GRE Stack-of-Stars Volume Interpolated Breath-Hold Examination (StarVIBE) Acquisition With That of a 3D-T1-GRE Volume Interpolated Breath-Hold Examination (VIBE) for Chest Staging During Whole-Body PET/MRI

BACKGROUND

Whole-body positron emission tomography/magnetic resonance imaging (WB-PET/MRI) is increasingly used in oncology. However, chest staging remains challenging.

PURPOSE

To compare the diagnostic performance of a free-breathing 3D-T1-GRE stack-of-stars volume interpolated breath-hold examination (StarVIBE) with that of a 3D-T1-GRE volume interpolated breath-hold examination (VIBE) during WB-PET/MRI for chest staging.

STUDY TYPE

Retrospective, cohort study.

POPULATION

One hundred and twenty-three patients were referred for initial staging of solid cancer, 46 of whom had pulmonary nodules and 14 had pulmonary metastasis.

FIELD STRENGTH/SEQUENCE

Free-breathing 3D-T1-GRE stack-of-stars (StarVIBE) and Cartesian 3D-T1-GRE VIBE at 3.0 T.

ASSESSMENT

Image quality was assessed using a 4-point scale and using the signal-to-noise ratio (SNR) of lung parenchyma and contrast-to-noise ratio (CNR) of pulmonary nodules. Diagnostic performances of both sequences were determined by three independent radiologists for detection of pulmonary nodules, lymph node involvement, and bone metastases using chest CT, pathology, and follow-up as reference standards.

STATISTICAL TESTS

Paired Student's t-test; chi-squared; Fisher's exact test. A P value <0.05 was considered statistically significant.

RESULTS

StarVIBE quality was judged as better in 34% of cases and at least equivalent to VIBE in 89% of cases, with significantly higher quality scores (4 [4-4] vs. 3 [3-4], respectively). SNR and CNR values were significantly higher with StarVIBE (8 ± 1.3 and 9.7 ± 4.6, respectively) than with VIBE (1.8 ± 0.2 and 5.5 ± 3.3, respectively). Compared to VIBE, StarVIBE showed significantly higher sensitivity (73% [95% CI 62-82] vs. 44% [95% CI 33-55], respectively) and specificity (95% [95% CI 88-99] vs. 67% [95% CI 56-77]) for pulmonary nodules detection and significantly higher sensitivity (100% [95% CI 89-100] vs. 67% [95% CI 48-82], respectively) for detection of lymph node involvement. Sensitivities for bone metastases detection were not significantly different (100% [95% CI 88-100] vs. 82% [95% CI 63-94], P = 0.054).

DATA CONCLUSION

Owing to improved SNR and CNR and spatial resolution, a free-breathing 3D stack-of-stars T1-GRE sequence improves chest staging in comparison with standard 3D-T1-GRE VIBE and may be integrated in WB-PET/MRI acquisitions for initial staging of solid cancer.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Impact of the 18F-FDG-PET/MRI on Metastatic Staging in Patients with Hepatocellular Carcinoma: Initial Results from 104 Patients

Optimal HCC therapeutic management relies on accurate tumor staging. Our aim was to assess the impact of ¹⁸F-FDG-WB-PET/MRI on HCC metastatic staging, compared with the standard of care CT-CAP/liver MRI combination, in patients with HCC referred on a curative intent or before transarterial radioembolization. One hundred and four consecutive patients followed for HCC were retrospectively included. The WB-PET/MRI was compared with the standard of care CT-CAP/liver MRI combination for HCC metastatic staging, with pathology, followup, and multidisciplinary board assessment as a reference standard. Thirty metastases were identified within 14 metastatic sites in 11 patients. The sensitivity of WB-PET/MRI for metastatic sites and metastatic patients was significantly higher than that of the CT-CAP/liver MRI combination (respectively 100% vs. 43%, p = 0.002; and 100% vs. 45%, p = 0.01). Metastatic sites missed by CT-CAP were bone (n = 5) and distant lymph node (n = 3) in BCLC C patients. For the remaining 93 nonmetastatic patients, three BCLC A patients identified as potentially metastatic on the CT-CAP/liver MRI combination were correctly ruled out with the WB-PET/MRI without significant increase in specificity (100% vs. 97%; p = 0.25). The WB-PET/MRI may improve HCC metastatic staging and could be performed as a “one-stop-shop” examination for HCC staging with a significant impact on therapeutic management in about 10% of patients especially in locally advanced HCC.

18F-sodium fluoride PET/MRI myocardial imaging in patients with suspected cardiac amyloidosis

BACKGROUND

We evaluated the diagnostic performance of 18F-NaF PET/MRI in patients with suspected cardiac amyloidosis (CA).

METHODS

Twenty-seven consecutive patients underwent myocardial PET 1 hour after injection of 4 MBq/kg 18F-NaF with simultaneous MRI including cine-MRI, T1 and T2 mapping, first-pass and late gadolinium enhancement (LGE). 18F-NaF uptake was measured visually and semi-quantitatively by calculating myocardium-to-blood pool (M/B) ratios. CA was confirmed histologically.

RESULTS

Transthyretin (TTR)-CA was diagnosed in 16 patients, light-chain (AL)-CA in 7, and no-CA in 4. Visual interpretation of 18F-NaF images revealed a relative increase in myocardial uptake in only 3 patients, all with TTR CA, and a relative decrease in 13, including 7 AL CA, 3 no-CA, and 3 TTR CA. M/B ratios were significantly higher in TTR CA (1.00 ± 0.12) than in AL CA (0.81 ± 0.06, P = 0.001) or in no-CA (0.73 ± 0.16, P = 0.006). The optimal M/B cut-off to distinguish TTR CA from AL CA was ≥ 0.90 (Fischer, P = 0.0005). By comparison, classification of patients using 99mTc-HMDP heart-to-mediastinum ratios with the previously published cut-off ≥ 1.21 reached higher significance (P < 0.0001). Among MRI parameters, myocardial T1, LGE score, and extracellular volume were higher in CA than in no-CA patients, 1409 ± 76 vs 1278 ± 35 ms (P = 0.004), 10.35 ± 5.30 vs 3.50 ± 3.42 (P = 0.03), and 46 ± 10 vs 33 ± 8 % (P = 0.01), respectively.

CONCLUSION

18F-NaF PET/MRI shows good diagnostic performance when semi-quantification is used. However, contrast is low and visual interpretation may be challenging in routine. PET/MRI could constitute a one-stop-shop evaluation of amyloid load and cardiac function in patients needing rapid work-up.

Clinical impact of dual-tracer FDOPA and FDG PET/CT for the evaluation of patients with parkinsonian syndromes

Parkinsonian syndromes include typical cases of idiopathic Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) associated with cognitive and vegetative disorders, which are more challenging to diagnose. The aim of this study was to assess -the value of dual-tracer imaging 6-fluoro-(18F)-L-DOPA (FDOPA) and fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), performed in routine patients demonstrating extrapyramidal signs and cognitive complains, for the diagnosis and management of parkinsonian syndromes.We retrospectively included 143 consecutive patients who underwent both FDOPA PET/CT (for the evaluation of parkinsonism) and FDG PET/CT (for the evaluation of cognitive complaints) in the same institution. The suspected clinical diagnosis before imaging and the final post-imaging diagnosis were collected by a dedicated questionnaire.FDOPA was pathological in 90.2% of cases, including 74.1% of PD, 3.5% of parkinsonian dementia and 7% of APS. FDG was normal or near normal in 58.7% of patients. A pattern of diffuse cortical hypometabolism was observed in the remaining patients, more frequently in APS than in PD patients (P = .001). Importantly, in 7.7% of cases dual-tracer PET/CT allowed to decide between several diagnostic hypotheses and led to a new diagnosis in 14.0%. Therefore, the management of these patients was modified, with clinical re-evaluation in a specialized unit and a control of neuropsychological tests and imaging.Dual-tracer PET/CT imaging may be a precious help in the diagnosis and management of parkinsonian syndromes.

FRI0439 PET-CT IN THE ASSESSMENT OF OSTEOARTICULAR INFECTIONS ASSOCIATED WITH INFECTIVE ENDOCARDITIS

Background:

Five to eleven percent of infective endocarditis (IE) are associated with a musculoskeletal infection. Thanks to its good sensitivity, the use of PET-CT in this pathology makes it possible to confirm the diagnosis by seeking valvular hypermetabolism but also by mapping distant septic foci.

Objectives:

The main objective of our study was to assess the prevalence of osteoarticular fixation (OAF) with PET-CT, symptomatic or not, in patients with IE. The secondary objectives were to determine predictive factors for osteoarticular infections such as the type of valve damage (native or prosthetic) and germ.

Methods:

This study was carried out on the basis of a prospective cohort of patients admitted in the department of cardiology in Henri Mondor Hospital for IE suspicion between August 2015 and July 2019. Demographic, clinical, bacteriological, imaging and therapeutic data have been collected. Patients matching Duke’s modified criteria according to ESC 2015 (Duke + IE) and / or a cardiac fixation according to standard whole-body PET-CT were included in the analysis. All of the PET-CT scans were reviewed by a nuclear medicine specialist to confirm whether or not there was a heart condition and to look for septic-looking OAF.

Results:

From this cohort, we included 90 IE Duke + patients and 42 patients with cardiac PET-CT fixation (including 31 IE Duke +). In the IE Duke + group, we found OAF in 18 patients (20%), 39% of whom were asymptomatic. There were 9 spondylodiscitis (4 on the cervical level, 7 on the thoracic level, and 2 on the lumbar level), 5 glenohumeral arthritis, 2 coxofemoral arthritis, 1 sternoclavicular arthritis and 1 sacroiliac arthritis. The IE affected the aortic valve in 50% of the cases and the mitral valve in 22%. In other cases, the infection involved the internal automatic defibrillator (ICD) or the pacemaker. The valves were prosthetic in 73% of the cases. The bacterial ecology was mainly represented by Enterococcus faecalis (39%) then staphylococcus aureus (17%) against 14% and 13% respectively in the entire IE Duke + group. In the group with cardiac PET-CT fixation, OAF was found in 10 patients (40%), 70% of whom were asymptomatic. Among them, there were 5 spondylodiscitis (2 cervico- thoracic and 3 exclusively thoracic), 2 glenohumeral arthritis (20%), 2 coxofemoral arthritis and 1 sternoclavicular arthritis. The IE affected the aortic valve in 60% of the cases, mitral in 30% of the cases and it was an infection on ICD in 10% of the cases. The main germs found were Enterococcus faecalis (30% of cases) and Staphylococcus epidermidis (20% of cases).

Conclusion:

In patients with IE, PET-CT seems to be interesting in detection of osteoarticular infections, and consequently, could impact the diagnosis and the treatment modalities. In our cohort, 1 patient in 5 had an OAF and nearly 40% of them were asymptomatic. The overrepresentation of enterococcus is consistent with recent data in the literature

References:

[1]Dahl A, Iversen K, Tonder N, Hoest N, Arpi M, Dalsgaard M, et al. Prevalence of Infective Endocarditis in Enterococcus faecalis Bacteremia. J Am Coll Cardiol. 16 juill 2019;74(2):193‑201.

Disclosure of Interests:

Benjamin HUGUES: None declared, Bérivan EMSEN: None declared, Julien TERNACLE: None declared, Raphaëlle HUGUET: None declared, Antonio FIORE: None declared, Raphaëlle LEPEULE: None declared, Xavier Chevalier: None declared, Mukedaisi ABULIZI: None declared, Florent Eymard Consultant of: Regenlab

Predictive value of brain 18F-FDG PET/CT in macrophagic myofasciitis?: A case report

RATIONALE

Although several functional studies have demonstrated that positron emission tomography/computed tomography with F-fluorodeoxyglucose (F-FDG PET/CT) appears to be efficient to identify a cerebral substrate in patients with known macrophagic myofasciitis (MMF), the predictive value of this imaging technique for MMF remains unclear.

PATIENT CONCERNS

We presented data and images of a 46-year-old woman.

DIAGNOSES

The patient was referred to our center for suspected MMF due to diffuse arthromyalgias and cognitive disorder (involving an impairment of visual selective attention and a weakness in executive functions revealed by neuropsychological assessment) which occurred few years after last vaccine injections.

INTERVENTIONS

After a first negative deltoid muscle biopsy, a brain F-FDG PET/CT was performed and revealed the known spatial pattern of a cerebral glucose hypometabolism involving occipital cortex, medial temporal areas, and cerebellum.

OUTCOMES

Given the clinical suspicion of MMF and brain F-FDG PET/CT findings, a 2nd deltoid muscle biopsy was performed and confirmed the diagnosis of MMF with typical histopathological features.

LESSONS

This case highlights the predictive value of brain F-FDG PET/CT as a noninvasive imaging tool for MMF diagnosis, even when muscle biopsy result comes back negative.

Determination of self-attenuation correction factor for lichen samples by using gamma-ray spectrometry

In this study, we determine the self attenuation correction factor for lichen samples collected from Erzurum, a city located in the eastern region of Turkey by using gamma-ray spectrometry. The self attenuation correction factor is calculated for 17 lichen samples with densities ranging from 0.683 g/cm3 to 0.886 g/cm3. The transmission method has been used to obtain self-attenuation correction factors. Self attenuation correction factor versus energy fit curve is presented. It is observed that self attenuation correction factor changes with density. At lower energies the self-attenuation correction factor has higher values. At higher energies it has smaller values and tends to become stable.

Evaluation of antioxidant and cytotoxic effects of olivetoric and physodic acid in cultured human amnion fibroblasts

It is known that lichens are utilized for the treatment of many diseases including ulcer, diabetes, and cancer for many years. Secondary metabolites in the structure of the lichens provide various activity properties for them. In the present study, cytotoxic and oxidative effects of main constituents of Pseudevernia furfuracea (L.) Zopf (Parmeliaceae), olivetoric acid (OA), and physodic acid (PA) were investigated on cultured human amnion fibroblasts (HAFs). OA and PA were isolated from P. furfuracea using column chromatography and their structures were determined by proton nuclear magnetic resonance and carbon-13 nuclear magnetic resonance. HAFs were incubated during 48 h in the presence of OA and PA, at different concentrations from 6.25 mg/L to 200 mg/L. OA showed higher cytotoxicity than PA. In fact, median inhibitory concentration values of OA and PA were 571.27 and 3373.69 mg/L, respectively. The lower concentrations (<50 mg/L) of OA and PA did not cause oxidative stress and genotoxicity; furthermore, they supported anti-oxidative capacity of HAFs. Therefore, all these data suggested that both tested metabolites, especially PA might be developed as natural health medicine to protect human body against oxidative stress and genotoxicity. As far as we know, this is the first report on the cytotoxic and anti-oxidative activities of OA and PA on HAFs.