Atrial dimension reference values in healthy participants using the biplane/monoplane method for clinical and research use

AIM

To provide reference values of the dimensions of the left and right atrium (RA) obtained using the biplane and monoplane methods, respectively, on two- and four-chamber views, which represent the standard projections acquired in clinical practice, and correlation with body surface area (BSA), age, and gender.

MATERIALS AND METHODS

Healthy volunteers, M:F = 1:1, including five participants per gender and age decile from 20 to 70 years, who underwent cardiovascular magnetic resonance imaging (CMR) were enrolled prospectively. Normal atrial reference values were calculated for male and female subpopulations and stratified by age. Atrial areas and volumes were assessed both as absolute values and indexed to BSA. Differences among genders and correlation with age were assessed. Intra- and interobserver reproducibility were assessed in a subpopulation.

RESULTS

Fifty participants (mean age 43.3 ± 14 years, 25 men) were evaluated. Image analysis took <1 minute for each subject (mean time 30 ± 5 seconds). Intra- and interobserver reproducibility were excellent (ICC >0.85 for all datasets). RA areas were significantly higher in males (p=0.0001). The left atrial (LA) surface did not show significant differences among genders. Atrial areas normalised to BSA did not show significant gender differences. Both right and left absolute atrial volumes turned out to be significantly higher in males (p=0.0001 and p=0.0047, respectively), and normalised to BSA remained significantly different only for the RA (p=0.0006). Neither atrial volume nor areas showed significant correlation with age.

CONCLUSIONS

The monoplane method is a fast and reproducible technique to assess atrial dimensions. Absolute atrial dimensions show significant variations among genders. Gender-specific reference ranges for atrial dimensions are recommended.

Radiomics: a new tool to differentiate adrenocortical adenoma from carcinoma

Background

The main challenge in the management of indeterminate incidentally discovered adrenal tumours is to differentiate benign from malignant lesions. In the absence of clear signs of invasion or metastases, imaging techniques do not always precisely define the nature of the mass. The present pilot study aimed to determine whether radiomics may predict malignancy in adrenocortical tumours.

Methods

CT images in unenhanced, arterial, and venous phases from 19 patients who had undergone resection of adrenocortical tumours and a cohort who had undergone surveillance for at least 5 years for incidentalomas were reviewed. A volume of interest was drawn for each lesion using dedicated software, and, for each phase, first-order (histogram) and second-order (grey-level colour matrix and run-length matrix) radiological features were extracted. Data were revised by an unsupervised machine learning approach using the K-means clustering technique.

Results

Of operated patients, nine had non-functional adenoma and 10 carcinoma. There were 11 patients in the surveillance group. Two first-order features in unenhanced CT and one in arterial CT, and 14 second-order parameters in unenhanced and venous CT and 10 second-order features in arterial CT, were able to differentiate adrenocortical carcinoma from adenoma (P < 0.050). After excluding two malignant outliers, the unsupervised machine learning approach correctly predicted malignancy in seven of eight adrenocortical carcinomas in all phases.

Conclusion

Radiomics with CT texture analysis was able to discriminate malignant from benign adrenocortical tumours, even by an unsupervised machine learning approach, in nearly all patients.

FRI0214 PERSISTENT LOW-GRADE FDG-PET VASCULAR INFLAMMATION IN REMITTED LVV-GCA PATIENTS IS ASSOCIATED TO A SIGNIFICANT HIGH RISK OF RELAPSE

Background:

Persistent low-grade vascular inflammation in giant cell arteritis (GCA) with large vessel involvement (LVV) treated patients could represent the expression of persistent subclinical disease activity or post-inflammatory vascular remodelling. Whether these findings have any impact on future vascular outcomes is still an unmet need.

Objectives:

To evaluate the frequency and evolution of FDG-PET low-grade vascular inflammation in remitted LVV-GCA patients.

Methods:

We included all consecutive patients classified as GCA with LVV involvement, with a minimum disease duration of 12 months and clinically remitted, who underwent to at least one PET/MR scan between January 2015 and January 2020. For each scan vessel’s metabolic activity was assessed using the Meller’s grading1. Low-grade inflammation was defined as Meller 1 and 2 (inferior or equal to liver), as reported in previous studies. Demographic and clinical data, as well as disease remission or flares, were recorded and compared to vascular metabolic activity.

Results:

In total 88 PET scans were performed in 54 LVV-GCA patients, predominantly female (77.8%), aged 68[7,8] years, with a regular BMI (23.9[2.8]) and with a long-standing disease (27[32.6] months). A subsequent PET/MR scan was available in 34 patients (median time between the two scans 9[6.3] months).

At first PET examination, low-grade metabolic activity was reported in 68,5% of the cases, while complete remission in 15% and high metabolic activity in 25%. Comparing patients with low-grade vascular inflammation to those with complete remission (Meller 0), they had lower disease duration (28[25.9] vs 73[68] months, but without significance) and they were treated with higher daily prednisone dosage (5[3.8] vs 0[2.2], p=0.042). No significant differences were noted in age, acute phase reactants and type of treatment. Moreover, when compared to those with high metabolic activity (Meller 3), the latter had only significantly higher CRP levels (8.3[13.8] vs 4.1[3.9], p=0.03) and lower disease duration (19[20.6] vs 28[25.9] months, but without significance). While no significant differences were noted in age and type of treatment (both glucocorticoids and immunosuppressants).

Among all patients with low-grade vascular inflammation, 81% of them underwent to steroids or immunosuppressants tapering due to clinical remission. At the subsequent PET examination, a worsening of metabolic activity (Meller 3) was found in 4/20 patients, with 1 clinical flare. While in 14/20 patients the subsequent PET revealed a persistent metabolic activity. Only in 2/20 there was a complete metabolic remission. Change or increase of the treatment regimen led to an improvement (Meller 0 or 1) in all the cases. Low-grade metabolic activity was associated with a significant increased risk of worsening/flare at the subsequent PET examination (RR 5.29[1.87-16.11], p=0.002).

Conclusion:

Low-grade vascular inflammation at PET examination is a common feature in remitted patients. It is associated with older age, lower disease duration and clinical remission. Treatment tapering is associated with an increased risk of worsening/flare. Further research is urgently needed to address this issue.

References:

[1]J. Meller et al., “Early diagnosis and follow-up of aortitis with [(18)F]FDG PET and MRI.,” Eur. J. Nucl. Med. Mol. Imaging, vol. 30, no. 5, pp. 730–6, May 2003.

Disclosure of Interests:

Roberto Padoan: None declared, Alessandro Tomelleri: None declared, Mara Felicetti: None declared, Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Elena Baldissera Speakers bureau: Novartis, Pfizer, Roche, Alpha Sigma, Sanofi, Filippo Crimì: None declared, Pietro Zucchetta: None declared, Diego Cecchin: None declared, Maria Picchio: None declared, Lorenzo Dagna Grant/research support from: Abbvie, BMS, Celgene, Janssen, MSD, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, SG, SOBI, Consultant of: Abbvie, Amgen, Biogen, BMS, Celltrion, Novartis, Pfizer, Roche, SG, and SOBI, Andrea Doria Consultant of: GSK, Pfizer, Abbvie, Novartis, Ely Lilly, Speakers bureau: UCB pharma, GSK, Pfizer, Janssen, Abbvie, Novartis, Ely Lilly, BMS, Franco Schiavon: None declared