Search

Cholangiocarcinoma (CC) is the most frequent malignant tumor of the biliary tract. The vast majority of cholangiocarcinomas are adenocarcinomas with a high proportion of fibrous stroma. Based on the macroscopic growth pattern, CC is classified as mass-forming, periductal infiltrating, or intraductal, with each type having its own characteristic imaging findings and prognostic outcome. The recently proposed pathological classification of cholangiocarcinoma into two types: perihilar large duct type and peripheral small duct and/or ductular type helps in better understanding of the morphology and the imaging appearances. Computed tomography (CT) and magnetic resonance imaging (MRI) remain the main tools of imaging. We aim to provide a comprehensive outline of the different subtypes and the rationale behind various imaging features of these subtypes. Cholangiocarcinoma is one of the more difficult tumors to treat and till date, surgery remains the only definitive curative treatment.

Each of the 3 morphological subtypes of cholangiocarcinoma has a different set of imaging differentials. Emulators of mass-forming cholangiocarcinoma include other primary and secondary hepatic malignancies, benign tumors and tumor-like mimics such as abscess, hemangioma and confluent hepatic fibrosis. Benign inflammatory biliary strictures constitute the major differential of periductal-infiltrative type and intraductal calculi are the main consideration for intraductal-growth type. CT and MRI are the standard imaging tools for characterization of cholangiocarcinoma and differentiating it from close mimics. Here we will describe the various tumoral and non-tumoral mimics of cholangiocarcinoma and discuss specific imaging features useful in differentiation.

OBJECTIVE. This study aims to compare the diagnostic accuracy of virtual unenhanced CT images derived from dual-source dual-energy contrast-enhanced CT with that of standard unenhanced CT images for evaluation of sialolithiasis. MATERIALS AND METHODS. All dual-energy CT studies of the neck performed during the preceding 5 years were reviewed for submandibular gland calculi. Only patients who had unenhanced CT and contrast-enhanced CT performed as part of the same evaluation were included in this study. This review yielded 30 patients. Virtual unenhanced CT images were derived from the dual-energy dataset and compared with the true unenhanced CT images by two separate radiologists who assessed the total number of calculi encountered, their location, the largest dimension, and the attenuation of the calculi. The radiation burden incurred for true unenhanced CT and virtual unenhanced CT and the total radiation burden were calculated. RESULTS. Our analysis revealed that measurements of stone size showed good interobserver agreement. The mean stone size was 7.9 ± 5.9 (SD) mm on virtual unenhanced CT and 8.4 ± 5.9 mm on true unenhanced CT (range, 2.0-31.8 mm); the difference was statistically insignificant. The mean stone attenuation differed considerably (p < 0.01) between the virtual and true unenhanced CT images (494.8 ± 187.5 HU and 924.4 ± 374.9 HU, respectively), but correlated well. The mean radiation dose for a dual-phase IV contrast-enhanced CT study was 23.13 mGy (volume CT dose index). The mean dose was 10.93 mGy for the true unenhanced CT phase, thereby suggesting a 47.25% reduction in administered radiation dose when a single-phase contrast-enhanced CT study with virtual unenhanced image reconstructions is performed. CONCLUSION. Virtual unenhanced CT images derived from dual-source dual-energy CT scans of the neck provide accurate assessment of sialolithiasis akin to that provided by conventional CT protocols but at only a fraction of the radiation dosage.

Calf pain or swelling is a common presentation to the emergency department. The differential diagnoses are wide. Deep vein thrombosis (DVT) is often the first diagnosis to be excluded given its potentially fatal complications. Musculoskeletal causes of calf pain or swelling such as Baker's cyst, muscle or tendon tear, soft tissue infection, and inflammation are not uncommon and can often be confidently diagnosed with ultrasonography (US). Familiarity with these conditions and the sonographic findings would be useful in making timely and correct diagnosis.

Radiologists typically spend long hours staring at the computer monitor. This unavoidable nature of our work can lead to detrimental effects on the eyes. Moreover, there is little awareness among radiologists with regards to such potential harm. Ocular hazards, such as computer vision syndrome, are increasingly becoming more relevant to the radiology community. In this article, we discuss the ocular occupational hazards faced by radiologists and suggestions that may help in minimizing such hazards.

Background In ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PPCI), current oral P2Y12 platelet inhibitors do not provide maximal platelet inhibition at the time of reperfusion. Furthermore, administration of cangrelor prior to reperfusion has been shown in pre-clinical studies to reduce myocardial infarct (MI) size. Therefore, we hypothesize that cangrelor administered prior to reperfusion in STEMI patients will reduce the incidence of microvascular obstruction (MVO) and limit MI size in STEMI patients treated with PPCI. Methods The platelet inhibition to target reperfusion injury (PITRI) trial, is a phase 2A, multi-center, double-blinded, randomized controlled trial, in which 210 STEMI patients will be randomized to receive either an intravenous (IV) bolus of cangrelor (30 μg/kg) followed by a 120-minute infusion (4 μg/kg/min) or matching saline placebo, initiated prior to reperfusion (NCT03102723). Results The study started in October 2017 and the anticipated end date would be July 2020. The primary end-point will be MI size quantified by cardiovascular magnetic resonance (CMR) on day 3 post-PPCI. Secondary endpoints will include markers of reperfusion, incidence of MVO, MI size, and adverse left ventricular remodeling at 6 months, and major adverse cardiac and cerebrovascular events. Summary The aim of the PITRI trial is to assess whether cangrelor administered prior to reperfusion would reduce acute MI size and MVO, as assessed by CMR.

International audience; Purpose: 4D flow magnetic resonance imaging (4D-MRI) allows time-resolved visualization of blood flow patterns, quantification of volumes, velocities, and advanced parameters, such as wall shear stress (WSS). As 4D-MRI enters the clinical arena, standardization and awareness of confounders are important. Our aim was to evaluate the equivalence of 4D flow-derived aortic hemodynamics in healthy volunteers using different sequences and field strengths.Methods: 4D-MRI was acquired in 10 healthy volunteers at 1.5T using three different prototype sequences, at 3T and at 7T (Siemens Healthineers). After evaluation of diagnostic quality in three segments (ascending-, descending aorta, aortic arch), peak velocity, flow volumes, and WSS were investigated. Equivalence limits for comparison of field strengths/sequences were based on the limits of Bland-Altman analyses of the intraobserver variability.Results: Non-diagnostic quality was found in 10/144 segments, 9/10 were obtained at 7T. Apart for the comparison of forward flow between sequence 1 and 3, the differences in measurements between field strengths/sequences exceeded the range of agreement. Significant differences were found between field strengths/sequences for forward flow (1.5T vs. 3T, 3T vs. 7T, sequence 1 vs. 3, 2 vs. 3 [P < .001]), WSS (1.5T vs. 3T [P < .05], sequence 1 vs. 2, 1 vs. 3, 2 vs. 3 [P < .001]), and peak velocity (1.5T vs. 7T, sequence 1 vs. 3 [P > .001]). All parameters at all field strengths/with all sequences correlated moderately to strongly (r ≥ 0.5).Conclusion: Data from all sequences could be acquired and resulting images showed sufficient quality for further analysis. However, the variability of the measurements of peak velocity, flow volumes, and WSS was higher when comparing field strengths/sequences as the equivalence limits defined by the intraobserver assessments.

A 44-year-old man presented with breathlessness and episodes of palpitations for the last one year. The imaging diagnosis of cardiac sarcoidosis was made based on chest radiography and cardiac magnetic resonance (MR) imaging findings, and was further confirmed by biopsy. Cardiac sarcoidosis is an uncommon entity, yet is potentially fatal with nonspecific clinical manifestations, including sudden cardiac death. Hence, it is important to diagnose and treat this entity at an early stage to improve morbidity and mortality. Cardiac MR imaging plays a pivotal role in facilitating diagnosis and monitoring therapeutic response. We describe the MR imaging features of cardiac sarcoidosis and discuss imaging features of other cardiomyopathies that may mimic cardiac sarcoidosis.

From conventional radiograph to magnetic resonance urography, imaging of urinary system has evolved with variety of investigations over the past several decades with each of them having advantages and limitations of their own. In the current era, computed tomography (CT) has emerged as a preferred investigations for evaluation of the urinary tract. There are various techniques involved in performing CT urography (CTU) with triple bolus technique (TB-CTU) currently drawing a special attention because of its low radiation exposure. This article aims to discuss the current techniques, indications, and clinical applications of CTU with illustrations.

Conductive hearing loss (CHL) is caused by the disruption of the sound conductive chain that, in turn, may be due to diseases of the external and middle ear. High-resolution computed tomography (CT) is the imaging modality of choice to evaluate CHL because of its excellent spatial resolution. Along with clinical and otoscopic findings, CT also helps in the diagnosis and preoperative planning. This pictorial review aims to illustrate the CT features of common conditions causing CHL that may arise from the external and middle ear, as well as highlights some of the key imaging features that are helpful in management.

Wunderlich syndrome is a rare entity characterised by spontaneous retroperitoneal haemorrhage with renal origin. We present a case of Wunderlich syndrome secondary to clotting dyscrasia in a 64-year-old woman. The patient experienced a second Wunderlich haemorrhagic event with metachronous pseudoaneurysm formation, which was likely secondary to the large subcapsular haematoma stripping the renal capsule and tearing the cortical arteries. Selective pseudoaneurysm embolisations were successfully performed on both occasions. This clinical entity, its imaging differential diagnoses and management are discussed.

Patients presenting with a painful swollen leg are not infrequently encountered at the emergency department and can pose a diagnostic dilemma for attending physicians. The potential causes of leg pain and swelling include trauma, infection, inflammation, and neurogenic, vascular, and iatrogenic conditions; with magnetic resonance imaging (MRI) being an important tool in evaluation. We describe the MRI features of various conditions causing painful swollen legs. We also discuss the differential diagnosis and the useful clinical and laboratory findings that radiologists should be aware of, in order to arrive at an accurate diagnosis.

A 64-year-old woman presented to the emergency department complaining of sudden onset of right side neck pain radiating to the right scapula and right sided weakness. There was no history of headache or similar episode in the past. No past history of diabetes mellitus, hypertension or cardiac disease was present. On physical examination, there was loss of power in right upper and lower limbs (right upper limb: 2/5 and right lower limb: 1/5). There was no loss of power in the left limb. Patient's blood pressure was 124/82 mmHg, heart rate of 90/minute and oxygen saturation was 99% on room air. There was no difference of blood pressure in the arms. Glasgow coma scale (GCS) was 15 and initial laboratory investigations were within normal limits. A 12-lead ECG showed no acute changes. Urgent non-enhanced computed tomography (CT) of the brain followed by a CT angiogram of neck and circle of Willis was performed as patient complained of severe neck pain. After discussion with the neurosurgeons, the patient underwent a Magnetic Resonance Imaging (MRI) of the whole spine.

A 56-year-old Chinese man presented with giddiness and vertigo. Subsequent chest radiography showed the classic scimitar sign of an abnormal pulmonary venous return. Further evaluation with non-contrast computed tomography substantiated the finding of a partial anomalous venous drainage pattern and identified an associated rare lung anomaly, horseshoe lung. The imaging findings of scimitar syndrome and its association with horseshoe lung are reviewed.

There are many other diseases affecting the lungs that are described briefly in this chapter. These can be encountered in the emergency department or can be discovered incidentally.

Large airways or the central airways are composed of trachea and bronchi. The human tracheobronchial tree has 23 generations with the lobar bronchi being the first generation. The proximal, approximately, 16 generations of bronchi have conductive function, while the distal airways take part in gas exchange with a transition zone between the two where the bronchioles have both functions (Fig. 2.1). The respiratory bronchiole, alveolar duct, and alveolar sac have pure gas exchange function. The measurements of the trachea are described in Table 2.1 [1, 2]. The tracheal wall is composed of multiple rigid C-shaped hyaline cartilages covering the anterolateral wall and a collapsible membrane in posterior wall composed of muscle (trachealis) and connective tissue. CT plays an essential role in the identification of lobar and segmental bronchi as well as fissures. This is important in preoperative localization of the endobronchial and parenchymal lesion. The right bronchus is wider, shorter, and more vertical than the left lung. This leads to higher chances of right endobronchial intubation. The right bronchus, after giving rise to upper lobe bronchus, continues as bronchus intermedius and bifurcates into longer right middle lobe bronchus and shorter right lower lobe bronchus. The left bronchus divides into an upper lobe and lower lobe bronchus and subsequently to their segmental bronchi. Lingular bronchus arises from the left upper lobe bronchus. The segmental bronchi help in localizing the bronchopulmonary segments (Table 2.2).

Energy efficiency in oil refineries is an effective measure to reduce greenhouse gas emissions and energy use. Research has focused on the application of heat integration in industries; however, little emphasis is given to the practical use of unreliable/unavailable data from the industries and its integration with the energy system. The study used temperature correction factors to produce a balanced heat exchanger network and study the use of excess heat for district heating. It also validated the proposed retrofits by analysing the impact of the retrofit on the area of all heat exchangers in the network. Finally, it evaluates the robustness of the results due to input temperatures and mass flow rates. A Pinch analysis of a section of plant was done before optimising the heat network. The thermodynamic ideal heating and cooling energy targets of the heat network were 74 MW, which exceeded the actual energy use by 20%. The pinch point was 254.7 °C at a global minimum temperature of 30 °C. Retrofits were proposed to reduce this inefficiency and amount of excess heat for district heating was quantified. The retrofits were simulated in PRO/II software to analyse its impact on the entire heat network. The best-case scenario had a net present value of 51 MDKK over 15 years, with avoided emissions equal to 11.4 KTonsCO2 eq./year. Uncertainty analysis, done through Monte Carlo simulation, found that the Energy Targets were quite robust against the defined uncertainties.

AIP Acute interstitial pneumonia COP Cryptogenic organizing pneumonia CTD Connective tissue disease CTD-ILD Connective tissue disease-related ILD DIP Desquamative interstitial pneumonia GGO Ground-glass opacity HP Hypersensitivity pneumonitis IIP Idiopathic interstitial pneumonia ILD Interstitial lung disease IPF Idiopathic pulmonary fibrosis LIP Lymphocytic interstitial pneumonia NSIP Nonspecific interstitial pneumonia OP Organizing pneumonia PPFE Pleuroparenchymal fibroelastosis RB Respiratory bronchiolitis UIP Usual interstitial pneumonia

Radiology investigations play an important role in the assessment of pulmonary artery. Imaging is utilized in the diagnosis of pulmonary embolism (PE) and in the evaluation of a patient with pulmonary artery hypertension (PAH). PE is the third most common cardiovascular disease after coronary artery disease and stroke. The precise incidence of PE is not well known, but European guidelines estimated the incidence from 0.5 to 1 in 1000 [1]. Acute PE is associated with mortality rates as high as 30% [1, 2]. The clinical presentation of acute PE is variable accounting for its underdiagnoses. Most of the patients present with sudden onset of dyspnea, while a significant proportion may present with chest pain indistinguishable from more common coronary artery disease [3]. A small subset of patients may present with nonspecific symptoms like cough, hemoptysis, or syncope. Since the majority of the PEs are due to deep venous thrombosis (DVT) in the legs, one must be aware of predisposing conditions for DVT and PE that include advanced age, overweight, coagulation disorders, underlying malignancy, hormone replacement therapy, and oral contraception.

Nodules by definition are lung opacities less than 3 cm in size [1]. Subcentimeter pulmonary nodules always pose a dilemma to reporting radiologist. Radiologist’s role doesn’t get over by just describing the number and size of the nodules. It is important to guide the referring physician and patient about the next course of action that may range from follow-up CT to percutaneous CT-guided intervention. In certain cases, CT can provide additional clues for the underlying diseases accounting for pulmonary nodules.

The imaging appearances of pulmonary pathologies can be classified into various patterns for the ease of description and to narrow down the differential diagnoses. Imaging pattern refers to a finding or multiple findings suggesting one or more specific conditions [1, 2]. Many characteristic signs have also been described in computed tomography (CT) and radiographs. Along with the clinical features, these signs help in localizing the lesion or in arriving at a diagnosis.

Mediastinal abnormalities are generally uncommon—the most frequently encountered abnormality being mediastinal masses. Chest radiograph still remains the initial investigation of choice in patients with mediastinal abnormalities. Rarely, a mediastinal mass may be identified in an asymptomatic patient on routine screening chest radiograph. Hence, the radiologist must be aware of the signs of identifying and localizing mediastinal masses. The signs may not be specific; hence a sign in isolation is inadequate in diagnosis. However, a combination of imaging signs helps in accurate localization of a mediastinal mass on a chest radiograph. The absence of a sign is equally important in localization of an abnormality. CT is the investigation of choice for further characterization, assessing the extent of disease, and staging of mediastinal masses. Similarly, mediastinitis and pneumomediastinum are initially evaluated by chest radiographs and usually followed by a CT examination.

The esophagus is a tubular structure measuring approximately 25 cm in length, connecting the pharynx and the stomach. Most of the esophagus lies in the thorax, with small cervical and intra-abdominal segments. The longest thoracic segment lies posterior to the trachea in the midline, until the tracheal bifurcation, after which it courses slightly left of the midline to cross the diaphragm via the diaphragmatic hiatus and forms the gastroesophageal junction. The abdominal esophagus lies posterior to the left lobe of the liver. The esophagus is therefore composed of a short cervical segment, a long thoracic segment, and a short abdominal segment [1, 2]. The esophageal wall consists of four layers: mucosa, submucosa, muscular layer, and external fibrous layer [3]. The upper third of the esophagus consists of striated muscles, gradually transitioning into completely unstriated muscles in the distal third. Columnar epithelium lines the distal third and gastroesophageal junction, with squamous epithelium lining the rest of the esophagus.

Computed tomography and magnetic resonance imaging are widely used for evaluation of patients with nasal masses, playing an integral role in their diagnosis and treatment. Inverted papilloma is a rare tumor of the sinonasal region that demonstrates characteristic imaging appearances. Preoperative diagnosis and precise tumor extent are essential for surgical planning as this tumor grows centrifugally and has high potential to recur following incomplete surgery. This pictorial review aims to illustrate the spectrum of imaging features of inverted papilloma and highlight the key features that are useful for making an accurate diagnosis of this condition. Common differential diagnoses are also discussed.

The rapid and mostly uncontrolled spread of the coronavirus disease 2019 pandemic over the past 4 months has overwhelmed many healthcare systems worldwide. In Singapore, while our public healthcare institutions were considered well prepared due to our prior experience with the SARS outbreak, there was an unexpected surge of infected patients over the recent 2 months to deal with. We describe our radiology department’s experience in modifying operational practices and implementing strict infection control measures aimed at minimizing disease transmission and mitigating the potential impact of possible staff infection. From the perspective of serving a medium-sized regional hospital and limited by physical and manpower constraints, our radiology department had to adapt quickly and modify our initial responses and practices as the disease scenario changed. We have also enumerated some guidelines for planning future radiology departments.

Introduction We aim to evaluate the frequency of use and changing practices for all out-of-hours interventional radiology (IR) procedures performed in a new hospital. Methods This is a 5 year retrospective review of all out-of-hours procedures performed by the Interventional Radiology team from July 2010 to June 2015. Number and category of procedures performed were identified from the RIS database. Results Of the 7140 procedures performed by IR over the 5 years, 764 were out-of-hours. The total number of out-of-hours cases performed annually by IR has increased by 240% from year 1 to year 5. The variety and distribution of out-of-hours work has shown a characteristic trend with rising requests for advanced procedures such as active haemorrhage control. Conclusion The rising number and complexity of cases for on-call IR further supports the need for a formal on-call rota, ideally 1:6, to provide a sustainable 24/7 service and optimize patient outcome in an acute hospital.

Purpose To evaluate the effect of changes in hematocrit level on myocardial extracellular volume (ECV) fraction, as quantified with cardiac magnetic resonance (MR) imaging in an animal model. Materials and Methods Thirteen adult male Sprague-Dawley rats underwent cardiac MR imaging before and after induction of anemia. MR imaging procedures, including unenhanced and contrast material-enhanced T1 mapping, were performed by using a saturation recovery Look-Locker sequence with a 9.4-T unit. An optimized T1 mapping sequence was established in the phantom study. Systolic function of the left ventricle (LV) was calculated from the cine images. Native and postcontrast T1 values of the LV myocardium at the midcavity level and LV blood pool, partition coefficients, and ECV were calculated. Histopathologic examination of the heart was performed after sacrifice. Intergroup comparison of variables was performed with the paired t test. Results The postanemia models exhibited lower hematocrit levels, postcontrast T1 values of the LV pool, and partition coefficients (mean, 45.7% ± 5.2 [standard deviation]; 563.8 msec ± 155.7; and 29.2 ± 3.5, respectively) than did the preanemia models (mean, 59.0% ± 4.1; 690.2 msec ± 109.7; and 38.2 ± 4.4, respectively) (P < .05 for all comparisons). There were no differences between the pre- and postanemia groups in terms of LV ejection fraction (mean, 72.7% ± 2.1 vs 73.2% ± 4.7; P = .78) and ECV (mean, 15.5% ± 2.0 vs 16.0% ± 1.9; P = .24). Conclusion Myocardial ECV measured with contrast-enhanced T1 mapping cardiac MR imaging did not significantly change despite changes in hematocrit level in anemic rat models. Extrapolation of this finding from animal models to human subjects suggests that ECV measured with MR imaging could be a robust parameter in anemic patients.