Insights into Imaging

In this century, medical imaging is at the heart of medical practice. Besides providing fast and accurate diagnosis, advances in radiology equipment offer new and previously non-existing options for treatment guidance with quite low morbidity, resulting in the improvement of health outcomes and quality of life for the patients. Although rapid technological development created new medical imaging modalities and methods, the same progress speed resulted in accelerated technical and functional obsolescence of the same medical imaging equipment, consequently creating a need for renewal. Older equipment has a high risk of failures and breakdowns, which might cause delays in diagnosis and treatment of the patient, and safety problems both for the patient and the medical staff. The European Society of Radiology is promoting the use of up-to-date equipment, especially in the context of the EuroSafe Imaging Campaign, as the use of up-to-date equipment will improve quality and safety in medical imaging. Every healthcare institution or authority should have a plan for medical imaging equipment upgrade or renewal. This plan should look forward a minimum of 5 years, with annual updates. Teaching points • Radiological equipment has a definite life cycle span, resulting in unavoidable breakdown and decrease or loss of image quality which renders equipment useless after a certain time period. • Equipment older than 10 years is no longer state-of-the art equipment and replacement is essential. Operating costs of older equipment will be high when compared with new equipment, and sometimes maintenance will be impossible if no spare parts are available. • Older equipment has a high risk of failure and breakdown, causing delays in diagnosis and treatment of the patient and safety problems both for the patient and the medical staff. • Every healthcare institution or authority should have a plan for medical imaging equipment upgrade or replacement. This plan should look forward a minimum of 5 years, with annual updating.

Intra-arterial digital subtraction angiography (DSA), magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) are imaging modalities used for diagnostic work-up of non-traumatic subarachnoid haemorrhage. The aim of our study was to compare the cost-effectiveness of MRA, DSA and CTA in the first year after the bleed. A decision model was used to calculate costs and benefits (in quality-adjusted life-years [QALYs]) that accrued to cohorts of 1,000 patients. Costs and characteristics of diagnostic tests, therapy, patients’ quality of life and associated costs were respected. The diagnostic strategy with highest QALYs and lowest costs was considered most cost-effective. DSA was the most effective diagnostic option, yielding on average 0.6039 QALYs (95 % CI, 0.5761–0.6327) per patient, followed by CTA 0.5983 QALYs (95 % CI, 0.5704–0.6278) and MRA 0.5947 QALYs (95 % CI, 0.5674–0.6237). Cost was lowest for DSA (39,808 €; 95 % CI, 37,182–42,663), followed by CTA (40,748 €; 95 % CI, 37,937–43,831) and MRA (41,814 €; 95 % CI, 38,730–45,146). A strategy of CTA followed by DSA if CTA was negative or coiling deemed not feasible, was as effective as DSA alone at average costs of 39,767€ (95 % CI, 36,903–42,402). A combined strategy of CTA and DSA was found to be the most cost-effective diagnostic approach. • We defined a standard model for cost-effectiveness analysis in diagnostic imaging. • Comparing total 1-year health costs and benefits, CTA is superior to MRA. • A strategy of combining CTA and DSA was found to be the most cost-effective diagnostic approach.

Pattern recognition is a key tool that enables radiologists to evoke certain diagnoses based on a radiologic appearance. In Shakespeare’s Hamlet, Polonius tells his son Laertes to dress well because “apparel oft proclaims the man”; this phrase is now expressed in modern parlance as “the clothes maketh the man”. Similarly in radiology, appearances are everything, and in the case of radiologic signs, occasionally “the clothes maketh the sign”. The radiologic signs described in this pictorial review resemble items of clothing, fabric types, headwear, or accessories and are found in the musculoskeletal, pulmonary, gastrointestinal, and genitourinary systems. These “clothing signs” serve as a useful visual trigger to help radiologists to identify particular disease entities. • Pattern recognition enables radiologists to evoke a diagnosis based on radiologic appearance. • The radiologic signs described in this review resemble clothing, fabric, or accessories. • These “clothing signs” serve as visual triggers that evoke particular disease entities.

Fibromuscular dysplasia (FMD) is an idiopathic, segmentary, non-inflammatory and non-atherosclerotic disease that can affect all layers of both small- and medium-calibre arteries. The prevalence of FMD is estimated between 4 and 6 % in the renal arteries and between 0.3 and 3 % in the cervico-encephalic arteries. FMD most frequently affects the renal, carotid and vertebral arteries, but it can theoretically affect any artery. Radiologists play an important role in the diagnosis of FMD, and good knowledge of FMD’s signs will certainly help reduce the delay between the first symptoms and diagnosis. The common string-of-beads aspect is well known, but less common presentations also have to be considered. These less common imaging findings include vascular loops, fusiform vascular ectasia, arterial dissection, aneurysm and subarachnoid haemorrhage. These radiologic presentations should be known by radiologists in order to diagnose possible FMD, particularly when present in young females or when associated with personal or familial hypertension, to reduce the delay between the onset of the first symptom and the final diagnosis. The patients have to be referred to specialised FMD centres for dedicated management. • Fibromuscular dysplasia is not a rare disease. • Radiologists should recognise less common presentations to orient specific management. • Vascular loops, fusiform vascular ectasia and a “string-of-beads” aspect are typical presentations. • Arterial dissection, aneurysm and subarachnoid haemorrhage are less typical radiologic presentations.

The prognosis of hepatocellular carcinoma (HCC) is still poor largely due to the high incidence of recurrence. We aimed to develop and validate predictive models of early postoperative recurrence for HCC using clinical and gadoxetic acid-enhanced magnetic resonance (MR) imaging-based findings. In this retrospective case-control study, 209 HCC patients, who underwent gadoxetic acid-enhanced MR imaging before curative-intent resection, were enrolled. Boruta algorithm and backward stepwise selection with Akaike information criterion (AIC) were used for variables selection Random forest, Gradient-Boosted decision tree and logistic regression model analysis were used for model development. The area under the receiver operating characteristic curve (AUC), calibration plots, and decision curve analysis were used to evaluate model’s performance. One random forest model with Boruta algorithm (RF-Boruta) was developed consisting of preoperative serum ALT and AFP levels and six MRI findings, while preoperative serum AST and AFP levels and four MRI findings were included in one logistic regression model with backward stepwise selection method (Logistic-AIC).The two predictive models demonstrated good discrimination performance in both the training set (RF-Boruta: AUC, 0.820; Logistic-AIC: AUC, 0.853), internal validation set (RF-Boruta: AUC, 0.857, Logistic-AIC: AUC, 0.812) and external validation set(RF-Boruta: AUC, 0.805, Logistic-AIC: AUC, 0.789). Besides, in both the internal validation and external validation sets, the RF-Boruta model outperformed Barcelona Clinic Liver Cancer (BCLC) stage (p < 0.05). The RF-Boruta and Logistic-AIC models with good prediction performance for early postoperative recurrence may lead to optimal and comprehensive treatment approaches, and further improve the prognosis of HCC after resection.

The olfactory pathway is composed of peripheral sinonasal and central sensorineural components. The wide variety of different pathologies that can affect the olfactory pathway reflect this complex anatomical relationship. Localising olfactory pathology can present a challenge to the reporting radiologist. This imaging review will illustrate the normal anatomy of the olfactory system and describe a systematic approach to considering olfactory dysfunction. Key concepts in image interpretation will be demonstrated using examples of olfactory pathway pathologies.

The number of diagnostic imaging examinations being undertaken in the UK is rising. Due to the expensive nature of producing these examinations and the risks associated with exposing living tissue to the ionising radiation used by many of the imaging techniques, this growth comes with both a financial and a human cost. In a time of limited resources, it is important that we are able to maximise the benefits which we extract from these resources. Therefore, a broad search of the current literature was undertaken to assess our current understanding of the nature of benefit available from diagnostic radiological images. Two broad categories of benefit were identified: primary benefit (n = 470) and secondary benefit (n = 49). Primary benefits are those which are related to the justification for undertaking the imaging, e.g., abnormality detection, to assist in diagnosis or staging, or acting as an aid to clinical decision making, or intervention. Secondary benefits are those that are not related to the justification for imaging, e.g., to promote patient engagement and understanding or to facilitate communication. Existing work considering primary benefits is comprehensive. Secondary benefit, however, is less well recognised and may not be reliably realised. Use of the image to realise these benefits has far-reaching potential. Particularly, there may be underexplored benefits which access to the images may provide to patients. This represents a gap in existing research which should be addressed.

Cholangiocarcinoma (CCA) is an aggressive and lethal malignancy with limited therapeutic options. Despite recent advances in diagnostic imaging for CCA, the early diagnosis of CCA and evaluation of tumor invasion into the bile duct and its surrounding tissues remain challenging. Most patients with CCA are diagnosed at an advanced stage, at which treatment options are limited. Molecular imaging is a promising diagnostic method for noninvasive imaging of biological events at the cellular and molecular level in vivo. Molecular imaging plays a key role in the early diagnosis, staging, and treatment-related evaluation and management of cancer. This review will describe different methods for molecular imaging of CCA, including nuclear medicine, magnetic resonance imaging, optical imaging, and multimodal imaging. The main challenges and future directions in this field are also discussed.

To investigate the anogenital distance in patients with and without testicular microlithiasis (TML). A total of 101 patients underwent a conventional standard clinical B-mode scrotal ultrasonography and scrotal MRI. The patients were divided into two groups: patients with TML and non-TML. The latter served as control group. The anogenital distance was measured by a straight line from center of the anus to the posterior base of scrotum using MRI. In the TML group, mean AGD was 5.4 (± 1.07) cm (range 29–79 mm), and in non-TML 5.9 (± 1.03) cm (range 35–85 mm) (p = 0.04). MRI is a useful tool to measure the AGD. It is easy to perform without any discomfort to patients. We found AGD to be lower in patients with TML.