Κυριακή, 5 Μαΐου 2019

La radiologia medica

National guidelines for dental diagnostic imaging in the developmental age


Radiologists' recommendations for additional imaging (RAI) in the inpatient setting

Abstract

Objective

The aim of our study was to measure the rate of radiologists' additional recommended imaging examinations (RAI) at a hospital-based inpatient setting and to estimate the influence on RAI of clinical variables.

Materials and methods

This retrospective study was approved by the institutional review board. Inpatients CT and US examinations interpreted by fifteen radiologists between October and December 2016 were studied. Information about RAI from radiology report texts was extracted manually. The analytic data set included the interpreting radiologists' years of experience, patient age, patient gender, radiologist gender, ordering service and "clinical question to be answered" as collected from the radiology request forms.

Results

Of the 1996 US and CT examinations performed between October and December 2016 in the inpatient setting, 34% (683 examinations) had a radiologists' RAI. The largest proportion of RAI was for chest CT, followed by PET-CT, abdominal CT and abdominal MRI. Patient age and gender had no impact on RAI. Radiologists' years of experience were inversely correlated to RAI. "Pneumonia" showed the highest rate of RAI due to follow-up of lung nodules.

Conclusion

A high percentage of RAI resulted from CT and US radiologists' reports. The largest proportion of RAI was for chest CT, followed by PET-CT, abdominal CT, and abdominal MRI. Radiologists' years of experience play an important role in the number of the requested RAI. Further studies with a larger cohort of radiologists are needed to confirm the role of radiologists' experience in RAI. Also, follow-up studies are warranted to assess the number of RAI that are actually acted upon by the referring physicians.



MRI findings and utility of DWI in the evaluation of solid parathyroid lesions

Abstract

Purpose

To evaluate the MRI findings of solid parathyroid lesions and to elaborate on a possible improvement of MRI detection of parathyroid lesions by the use of additional DWI.

Materials and methods

MRI and DWI properties of pathologically proven 20 solid parathyroid lesions were retrospectively reviewed. Mean ADC values (b50 + b400 + b800/3) of parathyroid lesions were compared with that of normal appearing thyroid parenchyma (TP), sternocleidomastoid muscle (SCM) and jugulodigastric lymph nodes (JDLN).

Results

Of lesions, 4 were parathyroid hyperplasia, 13 parathyroid adenoma and 3 parathyroid adenocarcinoma. All parathyroid lesions were very bright on fat-saturated T2W images. Parathyroid hyperplasia and adenoma were small sized, homogenous, well-defined and low on T1W, high on T2W and avidly enhancing. Parathyroid carcinoma was large sized, ill-defined and very heterogeneous on MRI including DWI. Means ADC values of parathyroid hyperplasia, adenoma, and adenocarcinoma, TP, SCM and JDLN were measured as 2.3 ± 0.14 × 10−3, 1.7 ± 0.45 × 10−3, 1.5 ± 1.48 × 10−3, 0.87 ± 0.40 × 10−3, 0.55 ± 0.21 × 10−3 and 0.96 ± 0.33 × 10−3 mm2/s, respectively. All parathyroid lesions had high diffusion properties comparing other soft tissue structures of head and neck region. By increasing strength (b value) of diffusion tensor on DWI, solid parathyroid lesions still kept their brightness comparing other soft tissue structures of head and neck region because of their high T2 properties.

Conclusion

Solid parathyroid lesions had higher diffusion properties comparing other soft tissues structures of head and neck region. This feature makes them easily differentiate from nearby structures on fat-saturated T2W and DWI.



Dynamic contrast-enhanced magnetic resonance imaging in locally advanced rectal cancer: role of perfusion parameters in the assessment of response to treatment

Abstract

Purpose

To correlate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters to tumor grading and to assess their reliability in predicting pathological complete response (pCR) before neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC).

Materials and methods

Forty patients (24 male; mean age, 67.3 ± 8.1 years) with histologically proven LARC who had undergone 3-Tesla DCE-MRI before (MRI_1) and after CRT (MRI_2) between August 2015 and February 2016 were included in this retrospective study. DCE-MRI parameters at MRI_1 and MRI_2 were extracted by two board certified radiologists in consensus reading with Olea Sphere 2.3 software using the extended Tofts model. Based on DCE-MRI results, patients were divided in complete responders (CR) and non-complete responders (nCR) and the perfusion parameters were correlated to tumor grading and pCR.

Results

Wash-out and Kep at MRI_1 showed significant correlation with LARC grading (P = 0.004 and 0.01, respectively). Ve showed a significant increase between MRI_1 (0.47 ± 0.27) and MRI_2 (0.63 ± 0.23; P = 0.007). Ktransmeasured at MRI_1 was significantly higher in CR (0.66 ± 0.48) compared to nCR (0.53 ± 0.34, P = 0.02).

Conclusion

Wash-out and Kep measured before CRT correlate with LARC grading. Ve changes during CRT, while Ktrans measured before CRT may predict the response to therapy. Therefore, DCE-MRI parameters can predict tumor aggressiveness and CRT efficacy, playing a role as imaging biomarkers in patients with LARC.



Overcoming metallic artefacts from orthopaedic wrist volar plating on a low-field MRI scanner

Abstract

Purpose

To quantitatively compare the artefact reduction between standard and metallic artefact reduction (MAR) fast spin echo (FSE) T2 sequences in a low-field magnetic resonance imaging (MRI) scanner (0.3 T) in patients with titanium volar wrist plating.

Materials and methods

Sixteen patients with fractures of the distal radius, treated with titanium volar wrist plating and screws, were examined using a dedicated 0.3 T MRI scanner. Coronal standard FSE T2, FSE T2 high bandwidth (HiBW) and FSE T2 view angle tilting (VAT) sequences were performed. Metallic artefact volume, consisting of both "black" and "bright" artefacts, was calculated for each sequence. Quantitative differences were compared using repeated measures ANOVA test (P < 0.05).

Results

FSE T2 HiBW and FSE T2 VAT showed a significant reduction in artefact volume compared to the standard sequence. Differences between the artefact volume of the standard FSE T2, HiBW and VAT sequences were statistically significant for both the "black" and "bright" artefacts (P < 0.0001). Differences between the 1.5 HiBW and VAT sequences were statistically significant (black P < 0.0001, bright P < 0.0302).

Conclusions

MAR sequences significantly reduced metallic artefacts in vivo using a 0.3 T MRI scanner.



Role of pretreatment 18F-FDG PET/CT parameters in predicting outcome of non-endemic EBV DNA-related nasopharyngeal cancer (NPC) patients treated with IMRT and chemotherapy

Abstract

Purpose

To evaluate the prognostic role of pretreatment 18F-FDG PET/CT metabolic parameters in non-endemic Epstein–Barr Virus (EBV DNA)-related nasopharyngeal cancer (NPC) patients treated with curative intensity-modulated radiation therapy (IMRT) with or without chemotherapy (CHT).

Materials/methods

We retrospectively reviewed clinical data of 160 consecutive non-metastatic NPC patients who received IMRT with or without CHT. Forty-nine out of 160 patients that underwent whole body 18F-FDG PET/CT at our institution for disease staging with a minimum follow-up to 12 months were included in this study. We evaluated the relationship between maximum and mean standardized uptake values (SUVmax and SUVmean, respectively), metabolic tumor volume and total lesion glycolysis (TLG) of primary tumor and cervical lymph nodes with disease-free survival (DFS) and overall survival (OS). We also investigated the prognostic role of clinical variables such as age, disease stage, plasma EBV DNA load (copies/ml), gross tumor volume of primary tumor and lymph nodes.

Results

Median follow-up was 55 months. Two- and 5-year OS were 95.8% and 90.5%, respectively, while DFS was 83.4% at both time points. SUVmax of primary tumor ≥ 18.8 g/ml and primary tumor TLG ≥ 203.1 g were significant prognostic factors of worse OS. Furthermore, stages IVB and EBV DNA load ≥ 3493 copies/ml were significantly associated with lower DFS. No correlation was found between PET parameters and plasma EBV DNA load.

Conclusion

Even in a limited series, our data suggested that SUVmax, SUVmean and TLG of primary tumor could predict a poor outcome in NPC patients also in non-endemic area hypothesizing their use for refinement of prognostication.



Diagnostic efficacy of model-based iterative reconstruction algorithm in an assessment of coronary artery in comparison with standard hybrid-Iterative reconstruction algorithm: dose reduction and image quality

Abstract

Purpose

To evaluate the image quality and radiation dose exposure of low-dose coronary CTA (cCTA) study, reconstructed with the new model-based iterative reconstruction algorithm (IMR), compared with standard hybrid-iterative reconstruction (iDose4) cCTA in patients with suspected coronary artery disease.

Materials and methods

Ninety-eight patients with an indication for coronary CT study were prospectively enrolled. Fifty-two patients (study group) underwent 256-MDCT low-dose cCTA (80 kV; automated-mAs; 60 mL of CM, 350 mgL/mL) with prospective ECG-triggering acquisition and IMR. A control group of 46 patients underwent 256-MDCT standard prospective ECG-gated protocol (100 kV; automated-mAs; 70 mL of CM, 400 mgL/mL; iDose4). Subjective and objective image quality (attenuation value, SD, SNR and CNR) were evaluated by two radiologists subjectively. Radiation dose exposure was quantified as DLP, CTDIvol and ED.

Results

Mean values of mAs were significantly lower for IMR-cCTA (167 ± 62 mAs) compared to iDose-cCTA (278 ± 55 mAs), p < 0.001. With a significant reduction of 38% in radiation dose exposure (DLP: IMR-cCTA 91.7 ± 26 mGy cm vs. iDose-cCTA 148.6 ± 35 mGy cm; p value < 0.001), despite the use of different CM, we found higher mean attenuation values of the coronary arteries in IMR group compared to iDose4 (mean density in LAD: 491HU IMR-cCTA vs. 443HU iDose-cCTA; p = 0.03). We observed a significant higher value of SNR and CNR in study group due to a lower noise level. Qualitative analysis did not reveal any significant differences between the two groups (p = 0.23).

Conclusions

Low-dose cCTA study combined with IMR reconstruction allows to correctly evaluate coronary arteries disease, offering high-quality images and significant radiation dose exposure reduction (38%), as compared to standard cCTA protocol.



Evaluation of US and MRI techniques for carotid stenosis: a novel phantom approach

Abstract

Carotid atherosclerosis is very important in the pathogenesis of cerebral ischemia. Ultrasonography (US) and magnetic resonance imaging (MRI) are the predominant noninvasive techniques capable to identify the presence and stage of intra-plaque hemorrage. In this work, we propose a novel dedicated phantom that can be used for both US and MRI scanners to evaluate carotid atherosclerotic lesions. The phantom consists of a polymethyl metacrylate (PMMA) diagonally crossed by a PMMA hollow cylinder simulating a blood vessel. To simulate a stenosis, we inserted a plastic hollow tube inside the cylinder. Quantitative image analysis, based on accuracy measurements, was performed on two US and two MRI scanners. The accuracy measurements have highlighted the use of the 3.0 T MRI scanner to characterize the vessel stenosis. However, no significant difference between US and MRI techniques was found in Fisher exact test and inter-rater agreement. The concordance correlation coefficient showed a moderate agreement between some methods. Agreement between 3.0 T and other methods results poor, and this could be due to the fact that the 3.0 T has a better resolution compared to a US and MR 1.5 T. These methods seem to have similar efficacies for the evaluation of vessel stenosis, legitimizing the use of the developed phantom as a versatile and reproducible instrument that could be used during quality controls programs.



Lumbosacral transitional vertebra in the young men population with low back pain: anatomical considerations and degenerations (transitional vertebra types in the young men population with low back pain)

Abstract

Introduction

To evaluate the prevalence of subtypes of congenital lumbosacral transition vertebra (LSTV) in young male populations with low back pain (LBP) and their relationship to lumbar disc and facet degeneration.

Materials and methods

1875 patients (male, aged; 18–40 years) with LBP were investigated retrospectively. Standard lumbar MRI protocol of sagittal, and axial T1 weighted images (WI) and T2 WI and coronal short tau inversion recovery (STIR) T2 WI were obtained. Castellvi classification of LSTV were used for subtyping. The level and above the level of LSTV were evaluated for the lumbar disc space and facet degeneration based on grading methods which compares subtype groups with each other.

Results

Prevalence of LSTV was 32% (600 of 1875). The most frequent LSTV types were type I (dysplastic enlarged transverse process; 66.5%) and type II (pseudoarticulation; 21.8%). Eight percent of the patients were type III (fusion) and 3.6% patients type IV (one transverse process fused and one with pseudoarticulation). The most commonly detected LSTV types were type I + II (88%) and all bilateral LSTV types were seen much more than unilateral types (bilateral versus unilateral 63.2%, 33.2%). The LSTV type I highly correlated with the disc degeneration and facet arthrosis. But the groups with higher grade of disc degeneration were type IV and III.

Conclusion

In young male patients with LBP, LSTV was found to be high in frequency and mostly occurred to be subtype I. LSTV type I and associated disk and facet degeneration were found to be remarkable in this group. Coronal T2 STIR images are useful in showing lumbosacral region anomalies and variants, and should be included in the routine lumbar MRI protocol.



Evaluation of CSF flow metrics in patients with communicating hydrocephalus and idiopathic intracranial hypertension

Abstract

Purpose

To search for CSF dynamics of idiopathic intracranial hypertension (IIH) and communicating hydrocephalus and any correlation between MRI findings, CSF metrics and CSF opening pressure in IIH.

Materials and methods

Healthy subjects (30) and subjects with IIH (29) and high-pressure communicating hydrocephalus (43) were enrolled. Nonparametric Kruskal–Wallis test (p = 0.05) was used to compare three groups, Mann–Whitney U test with Bonferroni correction to compare two groups (p = 0.016). Correlation of MRI findings of IIH with CSF metrics and CSF opening pressure was analyzed by Spearman's Rank correlation coefficient (p = 0.05).

Results

In IIH, no correlation between MRI findings and aqueductal stroke volume (ASV) but statistically significantly CSF opening pressure in the presence of transverse sinus compression was noted. Comparing with healthy subjects, ASV was nonsignificantly lower and standardized diastolic and sum and difference of systolic and diastolic flow durations were statistically significantly lower. Comparing with hydrocephalus, the width of prepontine cistern (PPC)/the width of aqueductus sylvii (AS) was significantly higher and other CSF metrics with standardized systolic and sum of systolic and diastolic flow durations were significantly lower. In hydrocephalus, ASV and peak velocities were significantly higher. Compared with normal group, PPC/AS and reverse/forward flow duration were significantly lower and other CSF metrics were significantly higher.

Conclusion

In hydrocephalus, significant increase in ASV and peak velocities were noted. In IIH, CSF opening pressure was statistically significantly high in the presence of transverse sinus compression and standardized diastolic flow durations were statistically significantly short that are probably effects of increased impedance of CSF flow against increased intracranial pressure and unchanged or even decreased intraventricular CSF volume.



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