85 research outputs found
A new physeteroid cetacean from the Lower Miocene of southern Italy: CT imaging, retrodeformation, systematics and palaeobiology of a sperm whale from the Pietra leccese
Herein we describe a new finding of a medium-sized sperm whale from the Burdigalian (Lower Miocene) of the Pietra leccese formation (southern Italy) on the basis of a partly prepared specimen that includes a partial cranium, seven detached teeth, the fragmentary right mandible and two partial vertebral bodies. Because of the overall compression of the specimen, we carried out a retro deformation of a 3D model of the cranium obtained via CT-scanning. The combined analysis of the original specimen and the retrodeformed model has allowed us to recognise that the studied specimen constitutes a new physeteroid taxon: Angelocetus cursiensis n. gen. n. sp., a longirostrine sperm whale characterised by a sideward projected supracranial basin, as evidenced by the overall displacement of its posteriormost margin. Based on a phylogenetic analysis, A. cursiensis n. gen. n. sp. is determined to be a crown physeteroid that does not belong to either the Physeteridae or the Kogiidae. The wide temporal fossa, elongated rostrum and slender teeth, as well as the skull dimensions (estimated bizygomatic width c. 550 mm) suggest a diet based on medium to large-sized bony fish that were likely captured by a raptorial pierce feeding strategy (as for most of the coeval Burdigalian physeteroids). Despite a seemingly low ecomorphological disparity, the high degree of taxonomic diversity of the Burdigalian physeteroids suggests that this time span represents a crucial phase for the evolutionary history of sperm whales
Average absorbed breast dose (2ABD): an easy radiation dose index for digital breast tomosynthesis
Background: To propose a practical and simple method to individually evaluate the average absorbed dose for digital breast tomosynthesis. Methods: The method is based on the estimate of incident air kerma (ka,i) on the breast surface. An analytical model was developed to calculate the ka,i from the tube voltage, tube load, breast thickness, x-ray tube yield, and anode-filter combination. A homogeneous phantom was employed to simulate the breast in experimental measurements and to assess the dose-depth relationship. The ka,i values were employed to calculate the “average absorbed breast dose” (2ABD) index. Four mammographic units were used to develop and test our method under many conditions close to clinical settings. The average glandular dose (AGD) calculated following the method described by Dance et al., and the 2ABD computed through our method (i.e., from the exposure parameters) were compared in a number of conditions. Results: A good agreement was obtained between the ka,i computed through our model and that measured under different clinical conditions: discrepancies < 6% were found in all conditions. 2ABD matches with a good accuracy the AGD for a 100% glandular-breast: the minimum, maximum, and mean differences were < 0.1%, 7%, and 2.4%, respectively; the discrepancies increase with decreasing breast glandularity. Conclusions: The proposed model, based on only few exposure parameters, represents a simple way to individually calculate an index, 2ABD, which can be interpreted as the average absorbed dose in a homogeneous phantom, approximating a 100% glandular breast. The method could be easily implemented in any mammographic device performing DBT
A New SteatoScore in the Evaluation of Non-Alcoholic Liver Disease in Oncologic Patients
PurposeThe aims of this study were to evaluate the reproducibility of a new multi-parametric steatoscore (new SteatoScore) in oncologic patients with non-alcoholic fatty liver disease (NAFLD) and to compare it with computed tomography (CT). Materials and MethodsFifty-one (31 men, 20 women) oncologic patients, with a mean age and weight of 63.9 years and 78.33 kg, respectively, were retrospectively enrolled in the study. Patients underwent ultrasound (US) and computed tomography (CT) examinations as part of their oncologic follow-up protocol. US examinations were performed by using a 3.5-MHz convex probe. During the US examination, three standardized clips were obtained in each patient. Two operators performed all measurements, one of whom repeated the processing twice in 1 year. Hepatic/renal ratio (HR), attenuation rate (AR), diaphragm visualization (DV), hepatic/portal vein ratio (HPV), and portal vein wall visualization (PVW) were acquired and calculated by using Matlab and inserted in a multi-parametric algorithm called new SteatoScore. On unenhanced CT scan, hepatic attenuation (HA), liver-spleen difference (L-S), and liver/spleen ratio (L/S) were measured by placement of a region of interest (ROI) within liver and spleen parenchyma, avoiding areas with vessels and biliary ducts. ResultsThe intra-observer variability was greater than the inter-observer one, with intraclass correlation coefficient (ICC) values of 0.94 and 0.97, respectively. Correlation between single US and CT parameters provided an agreement in no case exceeding 50%. New SteatoScore showed high reproducibility, and high coefficient of correlation with L-S (R = -0.64; p < 0.0001) and L/S (R = -0.62; p < 0.0001) at CT. ConclusionNew SteatoScore has a high reproducibility and shows a good correlation with unenhanced CT in evaluation of oncologic patients with NAFLD
Incorporating dose–volume histogram parameters of swallowing organs at risk in a videofluoroscopy-based predictive model of radiation-induced dysphagia after head and neck cancer intensity-modulated radiation therapy
Purpose: To develop a videofluoroscopy-based predictive model of radiation-induced dysphagia (RID) by incorporating DVH parameters of swallowing organs at risk (SWOARs) in a machine learning analysis. Methods: Videofluoroscopy (VF) was performed to assess the penetration-aspiration score (P/A) at baseline and at 6 and 12 months after RT. An RID predictive model was developed using dose to nine SWOARs and P/A-VF data at 6 and 12 months after treatment. A total of 72 dosimetric features for each patient were extracted from DVH and analyzed with linear support vector machine classification (SVC), logistic regression classification (LRC), and random forest classification (RFC). Results: 38 patients were evaluable. The relevance of SWOARs DVH features emerged both at 6 months (AUC 0.82 with SVC; 0.80 with LRC; and 0.83 with RFC) and at 12 months (AUC 0.85 with SVC; 0.82 with LRC; and 0.94 with RFC). The SWOARs and the corresponding features with the highest relevance at 6 months resulted as the base of tongue (V65 and Dmean), the superior (Dmean) and medium constrictor muscle (V45, V55; V65; Dmp; Dmean; Dmax and Dmin), and the parotid glands (Dmean and Dmp). On the contrary, the features with the highest relevance at 12 months were the medium (V55; Dmin and Dmean) and inferior constrictor muscles (V55, V65 Dmin and Dmax), the glottis (V55 and Dmax), the cricopharyngeal muscle (Dmax), and the cervical esophagus (Dmax). Conclusion: We trained and cross-validated an RID predictive model with high discriminative ability at both 6 and 12 months after RT. We expect to improve the predictive power of this model by enlarging the number of training datasets
Clinical utility of dual energy computed tomography in gout: Current concepts and applications
Summary. Gout is the most common inflammatory arthritis and is increasing in prevalence and incidence in many countries worldwide. Dual Energy Computed Tomography (DECT) has a high diagnostic accuracy in established gout, but its diagnostic sensitivity is low in subjects with recent-onset gout. A meta-analysis of 17 studies showed a pooled sensitivity and specificity of 0.85 and 0.88, respectively. DECT is a useful diagnostic tool for patients with contraindications for joint aspiration or for those who refuse joint aspiration. This article aims to give an up to date review and summary of existing literature on the role and accuracy of DECT in the imaging of gout. (www.actabiomedica.it)
Advanced diagnostic imaging and intervention in tendon diseases
Degenerative tendon pathology represents one of the most frequent and disabling musculoskeletal disorders. Diagnostic radiology plays a fundamental role in the clinical evaluation of tendon pathologies. Moreover, several minimally invasive treatments can be performed under imaging guidance to treat tendon disorders, maximizing the efficacy and reducing procedural complications. In this review article we describe the most relevant diagnostic features of conventional and advanced US and MRI imaging in tendon disorders, along with the main options for image-guided intervention. (www.actabiomedica.it)
Evaluation of Dosimetric Properties in Full Field Digital Mammography (FFDM) - Development of a New Dose Index
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Baseline computed-tomography (CT)-evaluated sarcopenia predicts toxicity from first-line chemotherapy in metastatic gastric cancer (mGC) patients
Introduction: The impact of sarcopenia as a predictor of poor prognosis and its association with chemotherapy toxicity have been explored in different cancer types but remain controversial in mGC. Our aim was to explore the correlation between sarcopenia, evaluated at baseline CT scan, and toxicity and efficacy of first-line therapy.
Methods: We retrospectively analyzed pre-treatment CT scans from 78 mGC patients treated with first-line doublet chemotherapy comprising oxaliplatin and 5-fluorouracil/leucovorin or capecitabine (trastuzumab was administered in case of HER2-positive disease). Sarcopenia was defined according to previously published criteria (Martin L et al. J Clin Oncol 2013) by the use of the skeletal muscle index (SMI) and body mass index (BMI), according to gender-specific cut-off values. SMI was calculated as follows: cross-sectional skeletal muscle area (SMA) measured at the level of the third lumbar vertebra / (height)2 (m2). Toxicities were graded according to NCI CTCAE v.4.0. Association between the presence of sarcopenia and different adverse events was evaluated by Chi-square test. Correlation with response rate (RR, evaluated according to RECIST criteria 1.1), progression-free survival (PFS) and overall survival (OS) was assessed by the use of the log-rank test.
Results: Sarcopenia was evident in 34 (44%) patients. We observed a significant association between the presence of sarcopenia at baseline assessment and a higher risk of severe (i.e. grade 3-4) neutropenia (38% versus 18%; p = 0.048) and a higher risk of any grade mucosal toxicities (56% versus 34%; p = 0.045). None of the other investigated clinical factors (comprising age, gender, performance status, sites of metastases and previous surgery on primary tumor) was associated with the risk of toxicity. Neither sarcopenia nor the other evaluated clinical parameters were associated with outcome as measured by RR, PFS, and OS: the only exception was performance status, which was confirmed a major prognostic determinant in terms of PFS and OS.
Conclusion: Our experience identified sarcopenia as a potential determinant of the risk of hematologic and mucosal toxicities from first-line platinum plus fluoropyrimidine chemotherapy in mGC patients. Sarcopenia was apparently not associated with benefit from treatment and survival, but larger studies are needed to address this issue. Strategies aiming at improving the nutritional status of mGC patients are warranted to optimize the risk-to-benefit ratio of available treatments
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