Radiographers' assessment of referrals for CT and MR imaging using a web-based data collection tool

IntroductionThere is limited research related to the radiographers' role in assessing of radiology referrals to justify imaging. This study investigated radiographers' compliance with guidelines in the assessment of CT and MRI referrals and factors that influenced their performance.MethodsThis research was facilitated by the EFRS Research Hub at ECR 2019. Five radiology referral scenarios for CT and/or MRI were distributed to radiographers, as determined by their scope of practice, who volunteered at the Research Hub. A web-based data collection tool was used. The radiographers were required to determine the appropriateness of each referral, highlight any concerns and recommend suitable investigations if applicable. Linear regression analysis was used to determine whether postgraduate qualification, grade/role of the radiographer and use of guidelines influenced the radiographers' performance in assessing the referrals.ResultsParticipants originated from 24 countries (n = 51 CT, n = 40 MRI), the majority originating from the UK, Ireland, Italy, Spain, Norway and Austria. Responses consistent with guidelines were 58% and 57% for CT and MRI, respectively. Possession of an MSc qualification in CT was a significant factor of influence for a higher consistency with guidelines (p = 0.02) in CT. Employment as a radiographer in a lead professional role and/or educator was a significant factor of influence for a higher consistency with guidelines in MRI (p = 0.01).ConclusionA total of 58% for CT and 57% for MRI of the radiographers' responses complied with guidelines. Factors such as postgraduate education and leading professional roles are associated with better performance.Implications for practiceConsidering qualifications, experience and managerial role is vital before radiographers are delegated task of justifying CT and MR Imaging.     

源自大脑CT灌注数据的非时变重建的高质量CT血管成像

目的提出一个简单且稳定的,由CT灌注数据重建出高质量CT血管影像的成像技术,并与当前使用的CT血管成像技术进行对比。材料与方法本研究为包括连续25例脑卒中病人在内的回顾性研究,经学术审查委员会批准,通过用先前时间滤过的时间敏感技术由CT灌注数据产生     

MR-based attenuation correction for torso-PET/MR imaging: pitfalls in mapping MR to CT data

PURPOSE: MR-based attenuation correction (AC) will become an integral part of combined PET/MR systems. Here, we propose a toolbox to validate MR-AC of clinical PET/MRI data sets. METHODS: Torso scans of ten patients were acquired on a combined PET/CT and on a 1.5-T MRI system. MR-based attenuation data were derived from the CT following MR-CT image co-registration and subsequent histogram matching. PET images were reconstructed after CT- (PET(CT)) and MR-based AC (PET(MRI)). Lesion-to-background (L/B) ratios were estimated on PET(CT) and PET(MRI). RESULTS: MR-CT histogram matching leads to a mean voxel intensity difference in the CT- and MR-based attenuation images of 12% (max). Mean differences between PET(MRI) and PET(CT) were 19% (max). L/B ratios were similar except for the lung where local misregistration and intensity transformation leads to a biased PET(MRI). CONCLUSION: Our toolbox can be used to study pitfalls in MR-AC. We found that co-registration accuracy and pixel value transformation determine the accuracy of PET(MRI).     

CT imaging of colitis

Computed tomography (CT) is widely used to assess patients with nonspecific abdominal pain or who are suspected of having colitis. The authors recommend multidetector CT with oral, rectal, and intravenous contrast material and thin sections, which can accurately demonstrate inflammatory changes in the colonic wall and help assess the extent of disease. In most cases, the final diagnosis of the type of colitis is based on clinical and laboratory data and colonoscopic and biopsy findings, but specific CT features help narrow the differential diagnosis. Ulcerative colitis is distinguished from granulomatous colitis (Crohn disease) in terms of location of involvement, extent and appearance of colonic wall thickening, and type of complications. Ulcerative colitis and Crohn disease (granulomatous colitis) are rarely associated with ascites, which is often seen in infectious, ischemic, and pseudomembranous colitis. Pseudomembranous colitis also demonstrates marked wall thickening and, occasionally, skip areas but is associated with broad-spectrum antibiotic treatment or chemotherapy. Neutropenic colitis is characterized by right-sided colonic and ileal involvement, whereas ischemic colitis is characterized by vascular distribution pattern and history. Diverticulitis is a focal asymmetric process with fascial thickening and inflamed diverticula. Dilatation of a thick-walled appendix with increased enhancement and adjacent stranding suggests appendicitis, but inflammatory changes may extend to the cecum and terminal ileum. Epiploic appendagitis is a focal rim-enhancing area next to the colon, usually without any substantial colonic wall thickening.     

The use of flat-panel detectors for CT imaging

Clinical CT has reached a very high performance level by now. The introduction of spiral scanning and of multirow detectors have allowed to image even large body sections in very short time and with isotropic, high spatial resolution of better than 1 mm. For further improvements with respect to detector technology the use of flat-panel detectors (FPD), which have been developed for radiographic applications, is currently under investigation. In this article we discuss the general demands on CT detectors and specifically the suitability of FPDs with respect to CT imaging. FPDs offer excellent performance for the imaging of high-contrast structures with high spatial resolution.Low-contrast resolution and dose efficiency, however, do not yet reach the level of performance of dedicated CT detectors; temporal resolution is also limited. FPDs appear primarily suited for special applications in CT as for example 3D angiography or intraoperative imaging which also allows for improvements in workflow. For standard diagnostic CT they are not to be recommended at present, last but not least for dose reasons. The respective technical developments will have to be reassessed constantly in the future. The development of detector systems which are equally suited for radiography and CT constitutes an attractive goal.     

Functional imaging in CT

Fast data acquisition imaging technologies such as modern computed tomography (CT) allow contrast agents to be used as tracers and nuclear medicine methodology may be used to derive a variety of functional/physiological information from dynamic CT.

This article describes the theoretical basis and some practical applications of this idea including the measurement of perfusion, capillary permeability, vascular volumes, renal function and tumour responses to therapy.     

CT冠状动脉成像在冠心病诊断中的应用

目的:研究CT冠状动脉成像在冠心病早期诊断冠状动脉狭窄定性定量判读的作用。方法:对34例临床未发生急性冠脉综合征的冠心病患者,先后进行冠状动脉造影、128排双源CT冠状动脉成像。以冠状动脉造影为"金标准",计算CT冠状动脉成像敏感性、特异性、阳性预测值、阴性预测值。结果:①与冠状动脉造影相比,CT冠状动脉成像的敏感性为68%,特异性为97%,阳性预测值为89%,阴性预测值为90%。②CT冠状动脉成像有65个血管段图像质量差,约占12%,造成图像质量差的原因主要为钙化,心跳、呼吸伪影,少部分为管腔显示不良。结论:冠心病早期诊断中,CT冠状动脉成像可用作冠状动脉造影前筛选,CT冠状动脉成像阴性的患者不必行冠状动脉造影检查;CT冠状动脉成像阳性的患者,可行冠状动脉造影进一步确认病变。     

Quantification of knee joint fluid volume by MR imaging and CT using three-dimensional data processing

A noninvasive, quantitative technique to estimate joint fluid volume using three-dimensional (3D) processing of magnetic resonance (MR) imaging and CT data was evaluated. The mean accuracy error of this 3D approach with MR imaging, performed on five fresh cadaver knees, was -2.4 +/- 5.1% SD when volume estimates were based on heavily T2-weighted transverse images. A considerably higher mean accuracy error of -12.5 +/- 16.9% SD was found when the 3D approach with CT was used (four fresh cadaver knees), probably because of the small attenuation differences between articular soft-tissue structures and joint fluid. A mean precision error of 4.9 +/- 2.3% SD was found when two radiologists independently evaluated in vivo MR imaging studies of 12 knees with joint effusion. Because of the low CT accuracy, no in vivo studies were performed using CT. Thus, this preliminary study shows that quantification of joint fluid volume with 3D data processing offers more accuracy with MR imaging than with CT. The 3D approach with MR imaging provides a potential tool for clinical studies.     

Functional imaging in CT

Fast data acquisition imaging technologies such as modern computed tomography (CT) allow contrast agents to be used as tracers and nuclear medicine methodology may be used to derive a variety of functional/physiological information from dynamic CT.This article describes the theoretical basis and some practical applications of this idea including the measurement of perfusion, capillary permeability, vascular volumes, renal function and tumour responses to therapy.     

CT imaging of angiogenesis.

Tumor angiogenesis has significant implications in the diagnosis and treatment of various solid tumors. With the advent of fast, multi-slice CT scanners, CT imaging techniques capable of qualitative and quantitative analysis of tumor angiogenesis have been the subject of extensive investigation in the past 2 decades. The fundamental bases for CT imaging of angiogenesis are both the transport by blood flow of intravenously administered iodinated contrast material to tissue and the exchange by diffusion of these contrast molecules between the intravascular space and the extravascular interstitial space. With current fast CT scanners both tissue and vascular enhancement can be measured and traced over time at small time intervals to allow detailed modeling of the distribution of contrast agent in tissue. Both compartmental and distributed parameter models for contrast transport and exchange have been developed to quantify from the CT data the following angiogenesis related parameters: tissue blood flow, blood volume, mean transit time, contrast arrival time, capillary permeability surface area product and hepatic arterial fraction in case of the liver. This review addresses the following aspects of CT imaging of angiogenesis: 1) basic concepts related to the understanding of both compartmental and distributed parameter models; 2) comparison between both types of models; 3) practical issues with respect to the measurement of the arterial input function, which is required for the solution of both types of models; and, 4) illustration of the application of a distributed parameter model, the Johnson and Wilson model, in a number of experimental studies.     

Multiple-image in-room CT imaging guidance for interventional procedures

This HIPAA-compliant study was approved by the institutional review board; informed consent was not required. The purpose of this study was to retrospectively compare room use time for interventional procedures performed with multiple-image multi-detector row computed tomographic (CT) fluoroscopy (n=196) and single-image spiral CT fluoroscopy (n=175). There was no statistically significant difference in age, sex, or procedural type between the two groups. The median room use time was 90 minutes (interquartile range, 65-120 minutes) for the single-image technique and 75 minutes (interquartile range, 60-105 minutes) for the multiple-image technique. A two-sample t test with equal variance assumption on the log-transformed data showed a statistically significant difference in log time (P<.001) between the two groups. This time savings could potentially have a substantial clinical effect on resource use and patient throughput.     

CT imaging with ultra-high-resolution: Opportunities for cardiovascular imaging in clinical practice

Cardiovascular computed tomography (CT) angiography has become an established alternative to invasive catheter angiography. However, imaging artifacts due to partial volume effects with current systems hinder accurate evaluation of calcified or stented segments. Increased spatial resolution may allow to overcome these barriers to precise delineation of vascular disease. Recent developments in CT hardware and reconstruction have enabled CT angiography with ultra-high spatial resolution (UHRCT). In this review we aim to describe the methods to achieve greater spatial resolution in CT that are either in clinical or preclinical stage. In addition, we provide an overview of the available clinical evidence including diagnostic accuracy studies supporting improved vascular assessment with this technology. The benefits that can be gleaned from the initial experiences with UHRCT are promising. Using UHRCT, more patients may receive non-invasive characterization of coronary atherosclerosis by overcoming the limitations of current CT spatial resolution in visualizing and quantifying calcified, stented or small diameter segments. UHRCT may potentially impact existing management pathways as well as contribute to better understanding of the underlying pathophysiology of both macro- and microvascular disease.     

Feasibility study of CT perfusion imaging for prostate carcinoma

Objective

The aim of this feasibility study was to obtain initial data with which to assess the efficiency of perfusion CT imaging (CTpI) and to compare this with magnetic resonance imaging (MRI) in the diagnosis of prostate carcinoma.

Materials and methods

This prospective study involved 25 patients with prostate carcinoma undergoing MRI and CTpI. All analyses were performed on T2-weighted images (T2WI), apparent diffusion coefficient (ADC) maps, diffusion-weighted images (DWI) and CTp images. We compared the performance of T2WI combined with DWI and CTp alone. The study was approved by the local ethics committee, and written informed consent was obtained from all patients.

Results

Tumours were present in 87 areas according to the histopathological results. The diagnostic performance of the T2WI+DWI+CTpI combination was significantly better than that of T2WI alone for prostate carcinoma (P?Conclusion CTp may be a valuable tool for detecting prostate carcinoma and may be preferred in cases where MRI is contraindicated. If this technique is combined with T2WI and DWI, its diagnostic value is enhanced.

Key Points

? Perfusion CT is a helpful technique for prostate carcinoma diagnosis. ? Colour maps allow easy and rapid visual assessment of the functional changes. ? Colour maps of prostate carcinoma provide information about in vivo tumoral vascularity. ? CTp images may be added into routine radiological examinations. ? CTp provides guidance for histopathological correlation if biopsy is scheduled.     

Diagnostic value of CT perfusion imaging for parotid neoplasms

Objectives:

To assess the value of CT perfusion imaging in the differentiation of different histological categorization of benign tumours from malignant tumours in patients with parotid neoplasms.

Methods:

CT perfusion was successfully performed in 62 patients with parotid neoplasms whose diagnoses were confirmed by surgery or biopsy. The software generated a tissue time–density curve (TDC) and measured blood volume, blood flow, mean transit time and capillary permeability surface product. One-way ANOVA and receiver operating characteristic curves were used to analyse the difference and diagnostic efficacies of all perfusion data between each one of the benign tumours and malignancies. Statistical significance was assigned at the 5% level.

Results:

Pleomorphic adenomas mainly had a gradually ascending TDC. Warthin tumours showed a fast ascent followed by a fast descent. The TDC of basal cell adenomas had a fast ascension followed by a plateau, then a gradual descent. Malignant tumours mainly showed a rapidly ascending curve with a stable plateau. Significant differences were observed in blood flow, blood volume and mean transit time between pleomorphic adenomas and malignant tumours (p < 0.05) as well as in blood flow and blood volume between the Warthin tumours, the basal cell adenomas and the malignant tumours (p < 0.05). Differences in permeability surface between the basal cell adenomas and malignant tumours were significant (p < 0.01).

Conclusion:

CT perfusion of parotid gland could provide TDC and perfusion data, which were useful in the differentiation of different histological benign tumours and malignant tumours in the parotid gland.     

肾上腺淋巴瘤的CT 表现

目的：分析肾上腺淋巴瘤的C T表现,以熟悉对该病的认识。方法对20例经手术病理或穿刺活检证实的肾上腺淋巴瘤病例进行回顾性分析,男性15例,女性5例,年龄30～80岁,中位年龄65岁。所有病例均行C T 平扫、增强扫描,观察病变的C T表现并与临床和病理对照。结果20例肾上腺淋巴瘤病例中,双侧的18例,单侧的2例;病灶呈椭圆形25个,三角形的12个,肾上腺漫增厚的1个。肿瘤直径4．1～10．7cm ,平均6．3cm。动态增强动脉期轻度强化,门脉期中度强化,其中均匀强化30个病灶,不均均强化8个病灶。结论肾上腺淋巴瘤有特征性的C T表现,C T检查有助于与肾上腺其他肿瘤鉴别。     

Fidelity of three-dimensional CT imaging for detecting fracture gaps

Simulated femoral neck fractures with varying amounts of distraction were studied using four modifications in a volumetric, three-dimensional CT reconstruction program to allow an objective comparison of volumetric versus surface (thresholded) rendering. Binary classification caused spurious fusion of gaps less than 2.0 mm or, at settings preserving these gaps, produced false holes in adjacent bone. Fracture gaps were visible to 0.0 mm using volumetric CT image rendering technique.