Liver Biliary Function Evaluation on a 1.5T Magnetic Resonance Imaging Scan by T1 Reduction Rate Assessment Using Variable-Flip-Angle Sequences.

OBJECTIVE: Magnetic resonance (MR) relaxometry is an absolute and reproducible quantitative method, compared with signal intensity for the evaluation of liver biliary function. This is obtainable by the T1 reduction rate (T1RR), as it carries a smaller systematic error than the pre/post contrast agent T1 measurement. We aimed to develop and test an MR T1 relaxometry tool tailored for the evaluation of liver T1RR after gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid administration on 1.5T MR. METHODS: In vitro/vivo (liver) T1RR values with two 3D FLASH variable-flip-angle sequences were calculated by a MATLAB algorithm. In vitro measurements were done by 2 physicists, in consensus. The prospective in vivo study was approved by the local ethical committee and performed on 13 normal/26 cirrhotic livers. A supplemental test in 5 normal/5 cirrhotic livers, out of the studied series, was done to compare the results of our method (without B1 inhomogeneity correction) and those of a standardized commercial tool (with B1 inhomogeneity correction). All in vivo evaluations were performed by 2 radiologists with 7 years of experience in abdominal imaging. Open-source Java-based software ImageJ was used to draw the free-hand regions of interest on liver section and for the measurement of hepatic T1RR values. The T1RR values of each group of patients were compared to assess statistically significant differences. All statistical analyses were performed with IBM-SPSS Statistics. In vivo evaluations, the intrareader and interreader reliability was assessed by intraclass correlation coefficient. RESULTS: Our method showed good accuracy in evaluating in vitro T1RR with a maximum percentage error of 9% (constant at various time points) with T1 values in the 200- to 1400-millisecond range. In vivo, a high concordance between the T1RR evaluated with the proposed method and that calculated from the standardized commercial software was verified ( P < 0.05). The median T1RRs were 74.8, 67.9, and 52.1 for the normal liver, Child-Pugh A, and Child-Pugh B cirrhotic groups, respectively. A very good agreement was found, both within intrareader and interreader reliability, with intraclass correlation coefficient values ranging from 0.88 to 0.95 and from 0.85 to 0.90, respectively. CONCLUSIONS: The proposed method allowed accurate reliable in vitro/vivo T1RR assessment evaluation of the liver biliary function after gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid administration.

Advanced and traditional chest MRI sequence for the clinical assessment of systemic sclerosis related interstitial lung disease, compared to CT: disease extent analysis and correlations with pulmonary function tests.

BACKGROUND: MRI is a radiation-free emerging alternative to CT in systemic sclerosis related interstitial lung disease (SSc-ILD) assessment. We aimed to compare a T2 radial TSE and a PD UTE MRI sequence with CT in SSc-ILD extent evaluation and correlations with pulmonary function tests (PFT). MATERIAL AND METHODS: 29 SSc-ILD patients underwent CT, MRI and PFT. ILD extent was visually assessed. Lin's concordance correlation coefficients (CCC) and Kruskal Wallis test (p-value < 0.05) were computed for inter-method comparison. Patients were divided in limited and extended disease, defining extended ILD with two methods: (A) ILD>30% or 10%20% or 20% with FVC%<70%. MRI Sensitivity, Specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and Accuracy were assessed. Pearson correlation coefficients r (p-value<0.025) were computed between ILD extents and PFT (FVC% and DLCO%). RESULTS: Median ILD extents were 11%, 11%, 10% on CT, radial TSE and UTE, respectively. CCC between CT and MRI was 0.95 for both sequences (Kruskal-Wallis p-value=0.64). Sensitivity, Specificity, PPV, NPV and Accuracy in identifying extended disease were: (A) 87.5 %, 100 %, 100 %, 95.5 and 96.6 % with radial TSE and 87.5 %, 95.2 %, 87.5 %, 95.2 and 93.1 % with UTE; (B) 86.7 %, 86.4 %, 66.7 %, 95.0 % and 86.2 % for both sequences. Pearson r of CT, radial TSE and UTE ILD extents with FVC were -0.66, -0.60 and -0.68 with FVC, -0.59, -0.56 and -0.57 with DLCO, respectively (p<0.002). CONCLUSIONS: MRI sequences may have similar accuracy to CT to determine SSc-ILD extent and severity, with analogous correlations with PFT.

Magnetic resonance imaging in naso-oropharyngeal carcinoma: role of texture analysis in the assessment of response to radiochemotherapy, a preliminary study.

OBJECTIVE: Identifying MRI texture parameters able to distinguish inflammation, fibrosis, and residual cancer in patients with naso-oropharynx carcinoma after radiochemotherapy (RT-CHT). MATERIAL AND METHODS: In this single-centre, observational, retrospective study, texture analysis was performed on ADC maps and post-gadolinium T1 images of patients with histological diagnosis of naso-oropharyngeal carcinoma treated with RT-CHT. An initial cohort of 99 patients was selected; 57 of them were later excluded. The final cohort of 42 patients was divided into 3 groups (inflammation, fibrosis, and residual cancer) according to MRI, 18F-FDG-PET/CT performed 3-4 months after RT-CHT, and biopsy. Pre-RT-CHT lesions and the corresponding anatomic area post-RT-CHT were segmented with 3D slicer software from which 107 textural features were derived. T-Student and Wilcoxon signed-rank tests were performed, and features with p-value < 0.01 were considered statistically significant. Cut-off values-obtained by ROC curves-to discriminate post-RT-CHT non-tumoural changes from residual cancer were calculated for the parameters statistically associated to the diseased status at follow-up. RESULTS: Two features-Energy and Grey Level Non-Uniformity-were statistically significant on T1 images in the comparison between 'positive' (residual cancer) and 'negative' patients (inflammation and fibrosis). Energy was also found to be statistically significant in both patients with fibrosis and residual cancer. Grey Level Non-Uniformity was significant in the differentiation between residual cancer and inflammation. Five features were statistically significant on ADC maps in the differentiation between 'positive' and 'negative' patients. The reduction in values of such features between pre- and post-RT-CHT was correlated with a good response to therapy. CONCLUSIONS: Texture analysis on post-gadolinium T1 images and ADC maps can differentiate residual cancer from fibrosis and inflammation in early follow-up of naso-oropharyngeal carcinoma treated with RT-CHT.

Ultrashort Echo-Time Magnetic Resonance Imaging Sequence in the Assessment of Systemic Sclerosis-Interstitial Lung Disease.

PURPOSE: To test respiratory-triggered ultrashort echo-time (UTE) Spiral VIBE-MRI sequence in systemic sclerosis-interstitial lung disease assessment compared with computed tomography (CT). MATERIAL AND METHODS: Fifty four SSc patients underwent chest CT and UTE (1.5 T). Two radiologists, independently and in consensus, verified ILD presence/absence and performed a semiquantitative analysis (sQA) of ILD, ground-glass opacities (GGO), reticulations and honeycombing (HC) extents on both scans. A CT software quantitative texture analysis (QA) was also performed. For ILD detection, intra-/inter-reader agreements were computed with Cohen K coefficient. UTE sensitivity and specificity were assessed. For extent assessments, intra-/inter-reader agreements and UTE performance against CT were computed by Lin's concordance coefficient (CCC). RESULTS: Three UTE were discarded for low quality, 51 subjects were included in the study. Of them, 42 QA segmentations were accepted. ILD was diagnosed in 39/51 CT. UTE intra-/inter-reader K in ILD diagnosis were 0.56 and 0.26. UTE showed 92.8% sensitivity and 75.0% specificity. ILD, GGO, and reticulation extents were 14.8%, 7.7%, and 7.1% on CT sQA and 13.0%, 11.2%, and 1.6% on CT QA. HC was <1% and not further considered. UTE intra-/inter-reader CCC were 0.92 and 0.89 for ILD extent and 0.84 and 0.79 for GGO extent. UTE RET extent intra-/inter-reader CCC were 0.22 and 0.18. UTE ILD and GGO extents CCC against CT sQA and QA were ≥0.93 and ≥0.88, respectively. RET extent CCC were 0.35 and 0.22 against sQA and QA, respectively. CONCLUSION: UTE Spiral VIBE-MRI sequence is reliable in assessing ILD and GGO extents in systemic sclerosis-interstitial lung disease patients.

A critical evaluation of computed tomography-derived depth of invasion in the preoperative assessment of oral cancer staging.

BACKGROUND: Depth of invasion (DOI) has been introduced into the latest TNM classification of oral squamous cell carcinoma (OSCC). Despite its primarily pathological definition (pDOI), a preoperative evaluation of a radiological DOI (rDOI) would be useful but a standard and practical definition is lacking. The primary aim of this study is to measure the rDOI by computed tomography (CT) and compare it to the pDOI in a cohort of OSCC patients. Then, we analyze the utility and reliability of rDOI in the preoperative setting. METHODS: 58 cases of OSCC operated at our Institution from 2016 to 2019 were included. After accounting for plane-specific shrinkage factors and for different oral subsites, we have compared pDOI and rDOI for each spatial plane by paired difference test and correlation coefficient. Radiological accuracy and survival analysis were also determined to identify rDOI's clinical value. RESULTS: For lateral tongue, pDOI was more strongly related with axial rDOI (P < 0.01); for hard palate, the best plane was the sagittal one (P < 0.01); in floor of mouth (FOM) lesions, the strongest correlation was with coronal rDOI (P < 0.01), as well as for cheek buccal mucosa; sagittal scans seem to be the best to evaluate dorsum of the tongue and retromolar trigone; gingiva (P < 0.01) was most correctly evaluated in the coronal plane. Overall accuracy of rDOI restaging was 75.41%. Disease-free survival seems to be worse as rDOI increases. CONCLUSIONS: We suggest that with a standardized imaging protocol patients could be better classified according to CT-derived DOI.

Spirometric assessment of emphysema presence and severity as measured by quantitative CT and CT-based radiomics in COPD.

BACKGROUND: The mechanisms underlying airflow obstruction in COPD cannot be distinguished by standard spirometry. We ascertain whether mathematical modeling of airway biomechanical properties, as assessed from spirometry, could provide estimates of emphysema presence and severity, as quantified by computed tomography (CT) metrics and CT-based radiomics. METHODS: We quantified presence and severity of emphysema by standard CT metrics (VIDA) and co-registration analysis (ImbioLDA) of inspiratory-expiratory CT in 194 COPD patients who underwent pulmonary function testing. According to percentages of low attenuation area below - 950 Hounsfield Units (%LAA-950insp) patients were classified as having no emphysema (NE) with %LAA-950insp < 6, moderate emphysema (ME) with %LAA-950insp ≥ 6 and < 14, and severe emphysema (SE) with %LAA-950insp ≥ 14. We also obtained stratified clusters of emphysema CT features by an automated unsupervised radiomics approach (CALIPER). An emphysema severity index (ESI), derived from mathematical modeling of the maximum expiratory flow-volume curve descending limb, was compared with pulmonary function data and the three CT classifications of emphysema presence and severity as derived from CT metrics and radiomics. RESULTS: ESI mean values and pulmonary function data differed significantly in the subgroups with different emphysema degree classified by VIDA, ImbioLDA and CALIPER (p < 0.001 by ANOVA). ESI differentiated NE from ME/SE CT-classified patients (sensitivity 0.80, specificity 0.85, AUC 0.86) and SE from ME CT-classified patients (sensitivity 0.82, specificity 0.87, AUC 0.88). CONCLUSIONS: Presence and severity of emphysema in patients with COPD, as quantified by CT metrics and radiomics can be estimated by mathematical modeling of airway function as derived from standard spirometry.

Age estimation by assessment of pulp chamber volume: a Bayesian network for the evaluation of dental evidence.

PURPOSE: The present study aimed to investigate the performance of a Bayesian method in the evaluation of dental age-related evidence collected by means of a geometrical approximation procedure of the pulp chamber volume. Measurement of this volume was based on three-dimensional cone beam computed tomography images. METHODS: The Bayesian method was applied by means of a probabilistic graphical model, namely a Bayesian network. Performance of that method was investigated in terms of accuracy and bias of the decisional outcomes. Influence of an informed elicitation of the prior belief of chronological age was also studied by means of a sensitivity analysis. RESULTS: Outcomes in terms of accuracy were adequate with standard requirements for forensic adult age estimation. Findings also indicated that the Bayesian method does not show a particular tendency towards under- or overestimation of the age variable. Outcomes of the sensitivity analysis showed that results on estimation are improved with a ration elicitation of the prior probabilities of age.

Head and neck effective dose and quantitative assessment of image quality: a study to compare cone beam CT and multislice spiral CT.

OBJECTIVES: To evaluate the effective dose and image quality of horizontal CBCT in comparison with multislice spiral CT (MSCT) in scans of the head, cervical spine, ear and dental arches. METHODS: A head and neck Alderson-Rando® phantom (The Phantom Laboratory, Salem, NY) equipped with 74 thermoluminescence dosemeters was exposed according to 5 different scans in CBCT and 4 different scans in MSCT. Spatial and contrast resolutions, in terms of modulation transfer function and contrast-to-noise ratio (CNR), were measured to obtain a quantitative assessment of image quality. RESULTS: The CBCT effective dose was 248, 249, 361, 565 and 688 µSv in the cervical spine, head, ear, dental arches with small field of view and dental arches with medium field of view, respectively. The MSCT effective dose was 3409, 1892, 660 and 812 µSv in the cervical spine, head, ear and dental arches, respectively. The modulation transfer function was 0.895 vs 0.347, 0.895 vs 0.275, 0.875 vs 0.342 and 0.961 vs 0.352 for CBCT vs MSCT in the cervical spine, head, ear and dental arches, respectively. Head and cervical spine MSCT showed greater CNR than CBCT, whereas CNR of the ear and dental arches showed comparable values. CONCLUSIONS: CBCT was preferable to MSCT for the ear and dental arches volumetric imaging due to its lower radiation dose and significantly higher spatial resolution. In the case of cervical spine and head imaging, MSCT should be generally recommended if a high contrast resolution is required, despite the greater radiation exposure.