Microwave ablation followed by cTACE in 5-cm HCC lesions: does a single-session approach affect liver function?

PURPOSE: Microwave ablation (MWA) and conventional transarterial chemoembolization (cTACE) are locoregional treatments commonly performed in very early, early and intermediate stages of hepatocellular carcinoma (HCC). Despite combined locoregional approaches have shown encouraging results in obtaining complete tumor necrosis, their application in a single session is poorly described. Our aim was to evaluate the safety and efficacy of single-session MWA and cTACE treatment in 5-cm HCCs and its influence on liver function. MATERIALS AND METHODS: All 5-cm HCCs treated by MWA and cTACE performed in a single-session in our Interventional Radiology unit between January 2020 and December 2022 were retrospectively recorded and analyzed. Patients with poor or missing pre- and post-treatment imaging were excluded. Technical success, clinical success, and complications rate were examined as primary endpoints. Pre- and post-treatment liver function laboratory parameters were also evaluated. RESULTS: A total of 15 lesions (mean lesion diameter, 5.0 ± 1.4 cm) in 15 patients (11 men; mean age, 67.1 ± 8.9 years) were retrospectively evaluated. Technical and clinical success were 100% and 73%, respectively. Four (27%) cases of partial response and no cases of progressive or stable disease were recorded. AST and ALT values have found to be significantly higher in post-treatment laboratory tests. No other significant differences between pre- and post-treatment laboratory values were registered. AST and ALT pre- and post-treatment higher differences (ΔAST and ΔALT) were significantly associated with a lower clinical success rate. CONCLUSION: MWA and cTACE single-session approach is safe and effective for 5-cm HCCs, without significant liver function impairment. A post-treatment increase in AST and ALT values may be a predictor for clinical failure.

The prominent role of percutaneous transarterial embolization in the treatment of anterior abdominal wall hematomas: the results of three high volume tertiary referral centers.

PURPOSE: Percutaneous transarterial embolization (PTE) represents a fast, safe and effective option for life-threatening anterior abdominal wall hematomas (AWHs) and those unresponsive to conservative treatment. Our study aims to assess cumulative results of safety, technical and clinical success of PTE performed in three high-volume tertiary referral centers and to evaluate the efficacy of the different embolic materials employed. MATERIALS AND METHODS: A consecutive series of 124 patients (72.8 ± 14.4 years) with AWHs of different etiology submitted to PTE were retrospectively collected and analyzed. Clinical success, defined as absence of recurrent bleeding within 96 h from PTE, was considered as primary endpoint. The results of the comparison of three groups based on embolic agent employed were also analyzed. RESULTS: Spontaneous AWHs accounted for 62.1%, iatrogenic for 21.8% and post-traumatic for 16.1% of cases. SARS-CoV-19 infection was present in 22.6% of patients. The most commonly embolized vessels were epigastric inferior artery (n = 127) and superior epigastric artery (n = 25). Technical and clinical success were 97.6 and 87.1%, respectively. Angiographic signs of active bleeding were detected in 85.5% of cases. Four (4%) major complications were reported. The comparison of the three groups of embolic agents (mechanical, particulate/fluid and combined) showed no statistically significant differences in terms of clinical success. SARS-CoV-2 infection was found to be an independent factor for recurrent bleeding and poor 30-day survival. CONCLUSION: PTE performed with all the embolic agent employed in our centers is a safe and effective tool in the treatment of life-threatening anterior AWH of each origin.

Cornerstones of CT urography: a shared document by the Italian board of urogenital radiology.

CT urography is a single term used to refer to different scanning protocols that can be applied for a number of clinical indications. If, on the one hand, this highlights the role of the radiologist in deciding the most suitable technique to perform according to the patient's needs, on the other hand, a certain confusion may arise due to the different technical and clinical variables that have to be taken into account. This has been well demonstrated by a previous work based on an online questionnaire administered to a population of Italian radiologists that brought out similarities as well as differences across the national country. Defining precise guidelines for each clinical scenario, although desirable, is a difficult task to accomplish, if not even unfeasible. According to the prementioned survey, five relevant topics concerning CT urography have been identified: definition and clinical indications, opacification of the excretory system, techniques, post-processing reconstructions, and radiation dose and utility of dual-energy CT. The aim of this work is to deepen and share knowledge about these main points in order to assist the radiology in the daily practice. Moreover, a synopsis of recommendations agreed by the Italian board of genitourinary imaging is provided.

Anatomical Variations of Anterior Ethmoidal Foramen and Cribriform Plate: Relations With Sex.

ABSTRACT: Position of anterior ethmoidal artery and height of lateral lamella of cribriform plate (LLCP) represent critical variants in endoscopy.In 200 maxillofacial computed tomography scans of patients the position of anterior ethmoidal foramen (AEF) in relation to ethmoid roof was recorded. The height of LLCP was measured and classified according to Keros classification.Differences in AEF position and distribution of Keros types, and LLCP height according to sex were assessed through chi-square test (P < 0.05) and 1-way analysis of covariance (ANCOVA) test, respectively (P < 0.05). Differences in LLCP height according to different AEF position were assessed through Mann-Whitney test (P < 0.05).No differences were observed in prevalence of AEF exposure according to sex (P > 0.05); LLCP height was higher in males than in females, with a higher frequency of Keros type 3 (P < 0.05). Moreover, subjects with AEF exposure had a significantly higher LLCP height (P < 0.01).Results highlighted innovative data useful for improving the knowledge of these sensitive variants.

2D shear wave elastography in evaluation of prognostic factors in breast cancer.

PURPOSE: To evaluate the reproducibility of the 2D shear wave elastography (2D-SWE) method and to identify the prognostic factors of breast lesions. METHODS: In this prospective study, 44 female patients were consecutively included from January 2020 to September 2021. All patients showing visible masses at B-mode ultrasound underwent to clinical evaluation, followed by qualitative and quantitative 2D-SWE by two different operators with over 15-year and 2-year experience, respectively. Subsequently, patients underwent to surgical treatment after core needle biopsy. Reproducibility of qualitative and quantitative 2D-SWE was evaluated by Cohen's kappa and intraclass correlation coefficient (ICC). Clinical, imaging, and histopathological data and 2D-SWE evaluations were analysed with Spearman's rank correlation test. RESULTS: The mean age of the patients was 55 years ± 12. The mean histological and ultrasound tumour size of were 23.1 mm ± 13.2 and 17.2 mm ± 10.2, respectively. The interobserver agreement showed a good reproducibility limited to the qualitative evaluation colour maps (Cohen's kappa = 0.603) and to the quantitative evaluation E ratio (ICC = 0.771). Correlation analysis between the ultrasound and 2D-SWE values and the clinical-pathological parameters showed a significant relationship between E ratio and Elston-Ellis grading (P < 0.030) and between tumour size and Elston-Ellis grading (P < 0.041). CONCLUSION: The 2D-SWE has shown good reproducibility among operators with different experience. It could be a promising tool in the evaluation of some prognostic factors in ultrasound visible breast cancer.

Temporal Bone Pneumatization: Relationship With Sex and Variants of the Ethmoid and Sphenoid Bone.

ABSTRACT: Pneumatization variants of the temporal bone have a crucial importance in several surgical interventions. However, very few data are known about possible correlation with other pneumatization variants.Pneumatization of glenoid fossa, petrous apex, and infralabyrinthine portion of temporal bone was assessed in 200 computed tomography scans, equally divided between males and females (18-92 years). Pneumatization variants of the ethmoid (concha bullosa, agger nasi, pneumatized crista galli) and the sphenoid sinuses (pneumatized pterygoid processes, anterior clinoid processes, dorsum sellae, volume) were recorded as well.Differences in prevalence of each pneumatization type according to sex and side, among different portions of the temporal bone, and between temporal bone and the pneumatized variants of the ethmoid bone and sphenoid sinuses, were assessed through chi-square test (P < 0.05). Differences in sphenoid volume among different pneumatization degrees of the temporal bone were assessed through 1-way analysis of covariance test (P < 0.05).Pneumatization of the petrous apex and the infralabyrinthine portion was significantly more frequent in males than in females, whereas pneumatization of the glenoid fossa was more often observed on the right side (P < 0.05). Variants of the temporal bone are all related one with each other in males, whereas in females only the relationship between pneumatized petrous apex and infralabyrinthine portion was found. Moreover, in females the pneumatized petrous apex was related with pneumatized anterior clinoid process, and the pneumatized infralabyrinthine portion was related with the sphenoid sinus volume.Results may be useful for predicting these important variants in planning surgical interventions of the cranial base.

Radiomic analysis of the optic nerve at the first episode of acute optic neuritis: an indicator of optic nerve pathology and a predictor of visual recovery?

OBJECTIVE: Retinal nerve fiber layer thickness (RNFL) is a biomarker of neuroaxonal loss and index of visual function in multiple sclerosis (MS). We aimed to assess the correlation between radiomic features and RNFL, visual acuity (VA) at patients' presentation, visual outcome (VO), and clinical diagnosis. METHODS: We reviewed imaging and clinical data of 25 patients with a first episode of optic neuritis (ON) (14 females, 11 males; 5 bilateral ON; 7 left ON; 13 right ON). All patients underwent a complete ophthalmological assessment, including visual acuity and RNFL, neurological evaluation, orbits MRI. Segmentation of the optic nerves was performed through 3D slicer open software to get radiomics analysis. All patients underwent a complete neuro-ophthalmological follow-up at 6 months to assess the VO, classified as: complete recovery, partial recovery, deficit persistence/relapse, or visual worsening and were diagnosed as MS or clinically isolated syndrome. RESULTS: We observed significant correlations between radiomic features and RNFL and between radiomic features and VA. Regression model analysis identified 1 radiomic feature with significant association with VO (Gray Level non-uniformity Normalized, p = 0.004) and 6 radiomic features with significant correlation with diagnosis (High Gray Level Zone Emphasis, p < 0.001; Entropy, p < 0.001, for T1 segmentation; Mean Absolute Deviation, p < 0.001; Coarseness < 0.001; Small Area Low Gray Level Emphasis, p < 0.001; Contrast, p = 0.008, for STIR segmentation). CONCLUSION: Orbits MRI analysis at the first episode of ON has the potential to assess the visual function and VO in ON patients, and predict MS development.

Third-generation iterative reconstruction on a dual-source, high-pitch, low-dose chest CT protocol with tin filter for spectral shaping at 100 kV: a study on a small series of COVID-19 patients.

OBJECTIVES: To investigate the role of third-generation iterative reconstruction (ADMIRE) in dual-source, high-pitch chest CT protocol with spectral shaping at 100 kVp in Coronavirus disease 2019 (COVID-19). METHODS: Confirmed COVID-19 inpatients undergoing to unenhanced chest CT were scanned with a dual-energy acquisition (DECT, 90/150Sn kV) and a dual-source, high-pitch acquisition with tin-filtered 100 kVp (LDCT). On the DECT with ADMIRE 3 (DECT3) were evaluated the pulmonary findings and their extension (25-point score). Two radiologists in consensus evaluated with 5-point scales the overall image quality, the anatomical structures, and the elementary findings on LDCT reconstructed with filtered backprojection (LDCT0), with ADMIRE 3 (LDCT3) and 5 (LDCT5), and on DECT3. The signal-to-noise ratio (SNR), the body mass index, the exposure times, and the radiation doses were recorded. RESULTS: Seventy-five patients (57 M/18F; median age: 63 y.o.) were included, with median pulmonary extension of 13/25 points. The imaging findings were detected in proportion comparable to the available literature. The ADMIRE significantly improved the SNR in LDCT (p < 0.00001) with almost no significant differences in overweight patients. The LDCT had median effective dose of 0.39 mSv and acquisition time of 0.71 s with significantly less motion artifacts than DECT (p < 0.00001). The DECT3 and LDCT3 provided the best image quality and depiction of pulmonary anatomy and imaging findings, with significant differences among all the series (p < 0.00001). CONCLUSION: The LDCT with spectral shaping and ADMIRE3 provided acceptable image quality in the evaluation of patients with COVID-19, with significantly reduced radiation dose and motion artifacts.

CT angiography of lower extremities from anatomy to traumatic and nontraumatic lesions: a pictorial review.

After the introduction and the quick improvement of multidetector computed tomography technology, computed tomographic angiography (CTA) has become the imaging examination of choice for the first assessment of patients affected by lower extremities acute disorders. The widespread availability of CT equipment, the high temporal and spatial resolution with post-processing reformation possibilities represent the main advantages of this technique, which can reliably identify different findings related to arterial vessel pathology, such as occlusion, dissection, active bleeding, and pseudoaneurysm. Radiologists should know the anatomy, the acquisition protocols, and the CTA appearances of the different vascular lesions. The right interpretation of CTA findings is essential to establish the best treatment management of each patient.

Volumetric analysis of Non-contrast Magnetic Resonance Lymphangiography in patients affected by lower extremities primary lymphedema.

AIM: Since the response to conservative and surgical treatments in lymphedema is based only on clinical evaluation, we want to propose a new technique for the volume calculation of lower extremities affected by lymphedema. MATERIALS AND METHODS: Ten female patients affected by primary LE of the lower limbs (mean age 33 ± 5 years; age range 16-42) underwent NCMRL in September 2019. Acquisition protocol included a STIR sequence (FOV 460 × 504 mm; matrix 315 × 384 pixel; voxel size 1.1 × 1.1 × 1.0 mm; TR 3000 ms; TE 254 ms; TI 160 ms). Two readers independently performed a manual segmentation with ITK-SNAP open-source software to assess the volume of the lower limbs. The agreement for volumetric segmentation between the two operators was assessed through intraclass correlation coefficient (ICC). RESULTS: Mean segmentation time was 5 ± 0.3 min. ICC demonstrated excellent intra-examiner agreements for both readers 1 (ICC = 0.9991, p < 0.0001) and 2 (ICC = 0.9989, p < 0.0001). Inter-reader agreement was excellent (ICC = 0.9991, p < 0.0001). CONCLUSIONS: Manual segmentation with ITK-SNAP of NCMRL examinations in patients affected by primary lower limb LE represents a reproducible procedure for an objective evaluation of volumes, useful for follow-up.

CT examination and 3D analysis of Egyptian animal mummies.

AIM: To report our experience on CT investigation of animal mummies, focusing on the practical and radiological aspects of the study, the acquisition parameters and the different reconstruction techniques. MATERIALS AND METHODS: Thirteen mummies underwent CT examination on the same CT scanner (Siemens sensation) with the following acquisition parameters: 120 kV; 140 mAs; slice thickness: 1 mm; reconstruction interval: 0.7 mm; and rotation time: 0.75 s. All datasets were reconstructed with both bone and soft tissue algorithms and archived on our picture archiving and communication system using their catalogue number as an identifier. Images were then transferred on IntelliSpace Portal (Philips Healthcare) for post-processing multiplanar and 3D reconstructions. The acquired data were submitted to anthropological analysis. RESULTS: CT enabled the identification of the bundles content: four cats with complete skeleton, one upper part of a cat mummy, one lower part of a cat mummy, one cat head with four cervical vertebrae, two crocodiles, two raptors, skeletons from one or more snakes and one mummy with dog appearance, containing long bones. All cats and hawks showed cervical fractures; in one cat, the skull was collapsed inwards, and in another cat, the head was turned backwards; one cat presented a skeleton more radiopaque than normal with evidence of cracks related to the use of the resins for mummification that were poured directly over the corpse. CONCLUSIONS: CT is a valuable noninvasive technique to study Egyptian mummies, enabling in-depth analysis while preserving the integrity of the mummy bundles, ensuring protection of a valuable archaeological resource.

Proposal of a low-dose, long-pitch, dual-source chest CT protocol on third-generation dual-source CT using a tin filter for spectral shaping at 100 kVp for CoronaVirus Disease 2019 (COVID-19) patients: a feasibility study.

AIM: To subjectively and objectively evaluate the feasibility and diagnostic reliability of a low-dose, long-pitch dual-source chest CT protocol on third-generation dual-source CT (DSCT) with spectral shaping at 100Sn kVp for COVID-19 patients. MATERIALS AND METHODS: Patients with COVID-19 and positive swab-test undergoing to a chest CT on third-generation DSCT were included. The imaging protocol included a dual-energy acquisition (HD-DECT, 90/150Sn kVp) and fast, low-dose, long-pitch CT, dual-source scan at 100Sn kVp (LDCT). Subjective (Likert Scales) and objective (signal-to-noise and contrast-to-noise ratios, SNR and CNR) analyses were performed; radiation dose and acquisition times were recorded. Nonparametric tests were used. RESULTS: The median radiation dose was lower for LDCT than HD-DECT (Effective dose, ED: 0.28 mSv vs. 3.28 mSv, p = 0.016). LDCT had median acquisition time of 0.62 s (vs 2.02 s, p = 0.016). SNR and CNR were significantly different in several thoracic structures between HD-DECT and LDCT, with exception of lung parenchyma. Qualitative analysis demonstrated significant reduction in motion artifacts (p = 0.031) with comparable diagnostic reliability between HD-DECT and LDCT. CONCLUSIONS: Ultra-low-dose, dual-source, fast CT protocol provides highly diagnostic images for COVID-19 with potential for reduction in dose and motion artifacts.

Sphenoid sinuses: pneumatisation and anatomical variants-what the radiologist needs to know and report to avoid intraoperative complications.

PURPOSE: Sphenoid sinuses are pneumatised structures, placed in the body of the sphenoid bone, with highly variable morphology. The strict relationships with vascular and nervous structures determine the importance of their anatomical variants in otorhinolaryngology and neurosurgery; a precise understanding of the complex anatomy and anatomic variations of these structures is pivotal for radiological diagnosis of paranasal sinuses pathology and for surgical planning, to avoid potential complications. Our aim is to describe the anatomical variants of sphenoid sinuses, and to help general radiologists and specialists in endoscopic surgery in becoming familiar with these sensitive anatomical structures. METHODS: A literature search of PubMed and Embase (Elsevier) databases was performed using the keywords "sphenoid sinus" and "anatomy, "sphenoid sinus" and "anatomic variants", "sphenoid sinus", and "anatomic variations". RESULTS: We described the anatomical variants of the sphenoid sinuses anatomy, according to their size, shape, degree of pneumatisation, protrusion of anatomical structures into their lumen, superimposition of ethmoid cells (Onodi cells), and presence of accessory septations CONCLUSION: The information provided by this study may help in the identification and description of the anatomical variations of the sphenoid sinuses and their relationship to neurovascular structures.

MRI of acute optic neuritis (ON) at the first episode: Can we predict the visual outcome and the development of multiple sclerosis (MS)?

AIM: Our aim was to assess MRI findings in the acute phase of ON and their correlation with visual acuity at presentation, visual outcome (VO) and MS development, to analyze a possible correlation between lesions number and diagnosis, and to assess correlation between orbits MRI and OCT. MATERIALS AND METHODS: We retrospectively studied 37 patients, who presented to our Emergency Department with an ON first episode from January 2015 to January 2017. Patients underwent immediately a complete neuro-ophthalmological evaluation, blood test, CSF analysis. MRI of brain, orbits, cervical spine was executed within 7 days from ON onset. Brain MRI was classified as: normal, non-specific, suspected demyelination, lesions with dissemination in space and time. Optic nerves findings were localized in three sites (intra-orbital, canalicular and chiasmal) and classified as: normal, STIR- alteration, altered contrast enhancement. Patients underwent neuro-ophthalmological follow-up and MRI at 6 months to assess VO (complete recovery, partial recovery, deficit persistence). Another follow-up at 1 year was performed to identify MS or clinically isolated syndrome (CIS). RESULTS: 64.8% patients received a diagnosis of MS; 35% of CIS. Lesions of the optic nerve were found in 65.8%. We observed statistically significant correlation between brain MRI pattern and diagnosis and between lesions number and diagnosis. We observed a statistically significant correlation between orbital MRI pattern and optical coherence tomography (OCT) results. MRI brain findings correlate with development of MS. MRI brain features and lesions number can predict the risk of MS conversion.

Dual-energy CT: theoretical principles and clinical applications.

The physical principles of dual-energy computed tomography (DECT) are as old as computed tomography (CT) itself. To understand the strengths and the limits of this technology, a brief overview of theoretical basis of DECT will be provided. Specific attention will be focused on the interaction of X-rays with matter, on the principles of attenuation of X-rays in CT toward the intrinsic limits of conventional CT, on the material decomposition algorithms (two- and three-basis-material decomposition algorithms) and on effective Rho-Z methods. The progresses in material decomposition algorithms, in computational power of computers and in CT hardware, lead to the development of different technological solutions for DECT in clinical practice. The clinical applications of DECT are briefly reviewed in relation to the specific algorithms.

Percutaneous management of bone metastases: state of the art, interventional strategies and joint position statement of the Italian College of MSK Radiology (ICoMSKR) and the Italian College of Interventional Radiology (ICIR).

Interventional radiology provides local management of bone metastases (BM) with a palliative intent in most cases, or with a curative intent in selected patients. Its role has rapidly expanded in the last decade, offering new treatment solutions often in combination with surgery, radiation therapy and medical treatments. The aim of the present paper is to increase awareness, acceptance and adoption of interventional radiology procedures for the treatment of BM; and to present the joint position of the Italian College of Musculoskeletal Radiology and the Italian College of Interventional Radiology.

Present role and future perspectives of interventional radiology in the treatment of painful bone lesions.

Interventional radiology has experienced an exponential growth in the last years. Nowadays it is possible to treat painful benign lesions or metastases with optimal results in terms of pain management and disease control. Among the benign lesions, osteoid osteoma is the most frequently treated with minimal invasive techniques and the results are excellent. Another lesion, traditionally treated with surgery (osteoblastoma) represent today another field of application. In the oncological field, metastases are, numerically, the most diffuse indications for treatment. Research carried out during the last decades has provided the interventional radiologist with a great variety of techniques of ablation and devices for monitoring the sensitive structures close to the target lesion. New ablation techniques and monitoring devices contribute to the achievement of significantly increasing rates of effectiveness and safety of interventional radiology procedures.

Hypoxia and tumor angiogenesis in the era of hepatocellular carcinoma transarterial loco-regional treatments.

This review focuses upon interactions and potential therapeutic targets in the 'vicious cycle' between hypoxia and neoangiogenesis following treatment of hepatocellular carcinoma with transarterial loco-regional therapies. Biomarkers correlated with angiogenesis have been studied by many authors as prognostic determinants following transarterial intrahepatic therapy. According to these results future therapies directed toward specific factors related to angiogenesis could play a significant role in preventing local tumor recurrence and remote metastasis.

The role of computed tomography (CT) in predicting diplopia in orbital blowout fractures (BOFs).

PURPOSE: The management of orbital blowout fractures (BOFs) is controversial: the evaluation of diplopia is the most important criterion for planning whether to undertake surgery. Our aim was to determine CT findings that may suggest the presence of diplopia when patients with BOFs cannot be adequately examined to plan an orbital repair. METHOD AND MATERIALS: We retrospectively evaluated CT of all patients presented to our Emergency Department for blunt craniofacial trauma (N = 3334) from January 2014 to March 2016, selecting patients with CT-demonstrated BOFs. The following CT variables were assessed: fracture location, fracture multifocality, bone fragments displacement, extraocular muscles (EOM) thickening, EOM entrapment, EOM displacement, EOM hooking, intraconal and extraconal emphysema, intraconal and extraconal hematoma, and fat herniation. All patients underwent Hess-Lancaster test, to establish the presence of diplopia. After performing group comparison with Pearson χ2 test, we derived our prediction model by using logistic regression, with diplopia as the prediction and CT variables as predictors. RESULTS: We observed 299 patients with BOFs, 46 (15.4%) with a Hess Lancaster test-proven diplopia. The CT variables with statistically significant difference between the group with diplopia and the group without diplopia were as follows: floor fracture (p = .014), bone fragments displacement (p = .001), multifocality (p = .005), EOM thickening (p = .001), EOM entrapment (p < .001), EOM displacement (p < .001), fat herniation (p = .003). The CT variables with significance as predictors of diplopia at multivariate analysis were as follows: orbital floor fracture (p value 0.015; odds ratio 2.871, 95% confidence interval of odds ratio 0.223-6.738), EOM displacement (p value 0.001; odds ratio 10.693, 95% confidence interval of odds ratio 3.761-30.401), EOM entrapment (p value 0.001; odds ratio 11.510, 95% confidence interval of odds ratio 3.059-43.306). CONCLUSION: The presence of diplopia can be suggested on the basis of CT findings after an orbital trauma.

Overuse of computed tomography for minor head injury in young patients: an analysis of promoting factors.

AIM: To assess the amount of computed tomography (CT) scans for minor head injury (MHI) performed in young patients in our emergency department (ED), not indicated by National Institute for Health and Clinical Excellence (NICE) and Canadian Computed Tomography Head Rules (CCHR), and to analyze factors contributing to unnecessary examinations. Secondary objectives were to calculate the effective dose, to establish the number of positive CT and to analyze which of the risk factors are correlated with positivity at CT; finally, to calculate sensitivity and specificity of NICE and CCHR in our population. MATERIALS AND METHODS: We retrospectively evaluated 493 CT scans of patients aged 18-45 years, collecting the following parameters from ED medical records: patient demographics, risk factors indicating the need of brain imaging, trauma mechanism, specialty and seniority of the referring physician. For each CT, the effective dose and the negativity/positivity were assessed. RESULTS: 357/493 (72%) and 347/493 (70%) examinations were not in line with the CCHR and NICE guidelines, respectively. No statistically significant difference between physician specialty (p = 0.29 for CCHR; p = 0.24 for NICE), nor between physician seniority and the amount of inappropriate examinations (p = 0.93 for CCHR, p = 0.97 for NICE) was found but CT scans requested by ED physicians were less inappropriate [p = 0.28, odds ratio (OR) 0.562, CI (95%) 0.336-0.939]. There was no statistically significant correlation between patient age and over-referral (p = 0.74 for NICE, p = 0.93 for CCHR). According to NICE, low speed motor vehicle accident (p = 0.009), motor vehicle accident with high energy impact (p < 0.01) and domestic injuries (p = 0.002) were associated with a higher rate of unwarranted CT; according to CCHR only motor vehicle accident with high energy impact showed a significant correlation with unwarranted CT scan (p < 0.001, OR 44.650, CI 33.123-1469.854). 2% of CT was positive. Multivariate analysis demonstrated that factors significantly associated with CT scan positivity included signs of suspected skull fracture (p < 0.001, OR 20.430, CI 2.727-153.052) and motor vehicle accident with high energy impact (p < 0.001, OR 220.650, CI 33.123-1469.854). In our series, CCHR showed sensitivity of 100%, specificity of 74%; NICE showed sensitivity of 100%, specificity of 72%. CONCLUSION: We observed an important overuse of head CT scans in MHI; the main promoting factor for inappropriate was injury mechanism. 2% of head CT were positive, correlating with signs of suspected skull fracture and motor vehicle accident with high energy impact.