Thrombus discrimination with electron density: potential implications for non-contrast computed tomography imaging.

The potential clinical usefulness of electron density (ED) imaging, that can be directly estimated using dual-layer spectral computed tomography (CT), has been poorly investigated. We explored whether ED imaging might improve thrombus identification compared to conventional imaging in vitro. We evaluated mechanical thrombectomy material obtained from patients with acute ischemic stroke (AIS) treated in a tertiary level stroke center and immediately fixed in 10% neutral buffered formalin and stored in polystyrene test tubes. The test tubes were immersed in a bucket of water for evaluation by spectral CT, along with scattered control tubes. All images were obtained using a dual-layer detector CT scanner. Each tube was assessed using multiparametric side-by-side view of conventional CT (120 kVp), low monoenergetic imaging (40 keV), and ED images. Fifty-eight polystyrene tubes were analyzed, comprising 52 tubes with thrombectomy material of at least 1 mm2 size obtained from 52 AIS patients, and six control tubes filled with formalin. ED imaging identified accurately the presence of material in all tubes, whereas 2 (3%) of the tubes containing thrombus were not identified by conventional CT, leading to a very good agreement between observers for the presence of material using conventional CT and ED imaging (kappa =0.84, P<0.001). Using ED imaging, thrombus material showed a mean density of 108.8±2.9 percent ED relative to water (%EDW), water had a mean density of 100.0±0.3 %EDW, and formalin a mean density of 103.5±1.2 %EDW. Compared to conventional imaging and 40 keV monoenergetic, ED imaging had a significantly higher signal-to-noise ratio (conventional 10.4±7.0, vs. 40 keV 11.5±8.4, vs. ED 490.0±304.5, P<0.001) and contrast-to-noise ratio (CNR) (conventional 4.3±4.3, vs. 40 keV 5.7±11.2, vs. ED 37.8±29.1, P<0.001). In this in-vitro study, we demonstrated improved visualization of thrombus with ED imaging compared to conventional imaging and low monoenergetic imaging, with a significant increase in CNR.

Extended CT Void Analysis in FDM Additive Manufacturing Components.

Additive manufacturing (AM) is the term for a number of processes for joining materials to build physical components from a digital 3D model. AM has multiple advantages over other construction techniques, such as freeform, customization, and waste reduction. However, AM components have been evaluated by destructive and non-destructive testing and have shown mechanical issues, such as reduced resistance, anisotropy and voids. The build direction affects the mechanical properties of the built part, including voids of different characteristics. The aim of this work is an extended analysis of void shape by means of X-ray computed tomography (CT) applied to fused deposition modeling (FDM) samples. Furthermore, a relation between the tensile mechanical properties and digital void measurements is established. The results of this work demonstrate that void characteristics such as quantity, size, sphericity and compactness show no obvious variations between the samples. However, the angle between the main void axis and the mechanical load axis α shows a relation for FDM components: when its mean value µ(α) is around 80 (degrees) the yield strength and Young's modulus are reduced. These results lead to the formulation of a novel criterion that predicts the mechanical behavior of AM components.

Renal Imaging: Core Curriculum 2019.

Renal imaging has become a fundamental part of clinical care for patients with kidney disease. Imaging strategies for the kidney have been evolving during the past hundred years and have been even more rapidly changing during the past couple of decades due to the development of modern computed tomographic techniques, magnetic resonance imaging, and more sophisticated ultrasonographic techniques, such as contrast-enhanced ultrasonography. Applying the correct radiologic study for the clinical situation maximizes the diagnostic accuracy of the imaging, and a judicious choice between techniques helps limit radiation dose and potential adverse events. This Core Curriculum outlines the imaging modalities currently in use in radiology departments and is divided into 3 sections: (1) a review of the development of renal imaging and an outline of modalities available to the nephrologist, (2) imaging strategies for select clinical situations, and (3) a discussion of some potential adverse events from imaging, including effects of iodinated contrast on kidney function, risks of gadolinium-based contrast agents in kidney failure, and potential risks of imaging techniques that use ionizing radiation.

Evaluation and Correlation between craniofacial bone densities and C1 and C2 cervical vertebrae using multislice computed tomography / Avaliação e Correlação entre as densidades ósseas craniofaciais e vértebras cervicais C1 e C2 por meio de tomografia computadorizada multislice

Objective: To evaluate the use of computed tomography (CT) as an osteoporosis screening tool, evaluating the relation between the bone mineral density (BMD) from maxilla and mandible with the cervical vertebrae, using the Hounsfield units (HU). Material and Methods: It was included in this study a convenience sample of 118 multislice CT examinations from patients who underwent maxilla, mandible and cervical vertebrae (C1 and C2) simultaneously scans. For each patient, the following regions on both sides of head CT scans were assessed in sagittal slice: above maxillary central and lateral incisors apexes; maxillary tuberosity; mandible head; mandible body endosteum; mandible body trabeculae and vertebrae C1 and C2. HU were measured in each area using a 0.5 cm region of interest (ROI) positioned in the center of the slice. Results: It was verified that there is a correlation between the BMD of the C1 and C2 vertebrae and the anterior region of the maxilla. It was not found correlation between the vertebrae, C1 and C2, and the other structures analyzed. Conclusions: This study showed that this method can be a good screening tool to diagnosis of osteoporosis, when evaluated the correlation between C1 and C2 vertebrae and anterior region of maxilla. More studies are necessary to evaluate the possibility of using CT as an osteoporosis screening tool. (AU)

Objetivos: Avaliar o uso da tomografia computadorizada como ferramenta de rastreamento da osteoporose, avaliando a relação entre a densidade mineral óssea da maxila e mandíbula com as vértebras cervicais, utilizando as unidades de Hounsfield. Material e métodos: Neste estudo foram incluidos uma amostra de 118 pacientes submetidos à exames de tomografia computadorizada multislice que apresentavam as estruturas anatomicas da maxila, mandibula e as vértebras cervicais (C1 e C2) simultaneamente. Para cada paciente, as seguintes regiões dos dois lados da tomografia computadorizada da cabeça foram avaliadas em corte sagital: acima dos ápices dos incisivos centrais e laterais superiores; tuberosidade maxilar; cabeça da mandíbula; endósteo do corpo da mandíbula; trabéculas do corpo da mandíbula e vértebras C1 e C2. As unidades de Hounsfield foram medidas em cada área usando uma região de interesse de 0,5 cm (ROI) posicionada no centro do corte. Resultados: Verificou-se uma correlação positiva entre a densidade mineral óssea das vértebras C1 e C2 e a região anterior da maxila. Não foram encontradas correlação entre as vértebras C1 e C2 e as demais estruturas analisadas. Conclusão: Este estudo mostrou que esse método pode ser uma ferramenta de triagem para o diagnóstico de osteoporose, quando avaliada a correlação entre as vértebras C1 e C2 e a região anterior da maxila. Mais estudos são necessários para avaliar a possibilidade do uso da tomografia computadorizada como ferramenta de rastreamento da osteoporose. (AU)

Imaging of pulmonary hypertension: an update.

Pulmonary hypertension (PH) is characterized by elevated pulmonary arterial pressure caused by a broad spectrum of congenital and acquired disease processes, which are currently divided into five groups based on the 2013 WHO classification. Imaging plays an important role in the evaluation and management of PH, including diagnosis, establishing etiology, quantification, prognostication and assessment of response to therapy. Multiple imaging modalities are available, including radiographs, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, echocardiography and invasive catheter angiography (ICA), each with their own advantages and disadvantages. In this article, we review the comprehensive role of imaging in the evaluation of PH.

Tracheal growth assessment in mongrel puppies (dogs) through multidetector CT.

The aim of this study was to describe the tracheal growth pattern and its zoometric relationship in related medium-sized mongrel puppies through adulthood. Fourteen puppies were studied. CT monitoring was performed monthly, starting in the 1st month of life through the 7th month and subsequently at the 9th and 12th months. Additionally, six zoometric measurements were performed. Dorsoventral (DV) and transverse (TV) diameters and the luminal area from C1 to T2 were obtained. The global tracheal growth pattern revealed an increase up to 13 times its initial size, reaching a plateau phase during the last trimester. The relationship between the DV and the TV internal diameters of the tracheal lumen did not change during growth. As previously reported, the cranial tracheal area was wider, while the caudal part gradually decreased towards T1-T2; this consideration is important since the more distal an endotracheal tube is inserted, the greater the risk that injury may occur. The linear correlation between the zoometric measurements and the tracheal ring areas was positive. This study provides evidence for the evaluation of the morphometry of the canine trachea during physiological growth using helicoidal CT as a non-invasive, accurate tool.

Cardiac Imaging in Systemic Diseases: What the Clinician should Know.

IMPORTANCE: Systemic diseases that affect the cardiovascular system constitute a diagnostic and therapeutic challenge for all specialists involved; imaging tools along with clinical suspicion play an essential role in their evaluation. These entities share neurological, immunological, renal, hematologic, oncologic, infectious and endocrine processes, all of which may have associated cardiac involvement. OBSERVATIONS: Recent advances in cardiac ultrasound, Computed Tomography (CT), cardiac Magnetic Resonance (CMR) and nuclear scintigraphy have impacted the management of these conditions when involving the heart since they provide valuable anatomical and functional information while avoiding the use of invasive techniques. For this review, bibliographic sources were gathered from diverse databases, including PubMed, Cochrane, EBSCO and Google Scholar, concentrating on English language publications dealing with the clinical use of these tools. CONCLUSION: Clinical suspicion should always guide the use of imaging since in many instances, these techniques only play a supportive role rather than representing a diagnostic gold standard. Early diagnosis is critical due to the fact that cardiac manifestations are commonly a late phenomenon.

Myocardial CT perfusion imaging for ischemia detection.

Coronary computed tomography angiography (CCTA) plays an important role in many specific scenarios such as in symptomatic patients with intermediate pretest of coronary artery disease (CAD), as well as in the triage of patients with acute chest pain with TIMI risk ≤2. However, it cannot detect the presence of associated ischemia, which is critical for clinical decision making among patients with moderate to severe stenosis. Although functional information can be obtained with different non-invasive tools, cardiac CT is the unique modality that can perform a comprehensive evaluation of coronary anatomy plus the functional significance of lesions. Myocardial CT perfusion (CTP) can be performed with different approaches such as static and dynamic CTP. In addition, static CTP can be performed using single energy CT (SECT) or dual energy CT (DECT). In this review, we will discuss the technical parameters and the available clinical evidence of static CTP using both SECT and DECT.

Imaging findings of adrenal primitive neuroectodermal tumors: a series of seven cases.

OBJECTIVE: To explore the imaging features of adrenal primitive neuroectodermal tumors (PNETs). MATERIALS AND METHODS: This retrospective study included seven patients with surgically and pathologically confirmed adrenal PNETs. Among them, six underwent computed tomography (CT) scans, and one underwent magnetic resonance imaging. The imaging findings, including size, shape, margin, hemorrhage, calcification, cystic degeneration, regional lymph nodes involvement, tumor thrombus formation and enhancement pattern, were retrospectively analyzed. RESULTS: Among the seven adrenal PNET patients, six were male, and one was female. The median age was 26 years (range 2-56 years). The disease generally presented with either insidious symptoms (n = 4) or non-specific symptoms, including right flank pain (n = 1) and left upper abdominal discomfort (n = 2). On the pre-enhanced CT images, the tumor usually appeared as a well-defined, rounded or oval, heterogeneous mass without calcification. Certain tissue characteristics, such as cystic degeneration (n = 5), capsule (n = 4) and hemorrhage (n = 2), were observed. Regional lymph node involvement was observed in three cases, and renal vein thrombus was observed in one case. All cases showed mild heterogeneous enhancement of the tumor on the enhanced CT images. CONCLUSION: An adrenal PNET commonly presents as a relatively large, well-defined, heterogeneous mass with cystic degeneration, necrosis and a characteristic mild contrast-enhancement pattern on multiphase enhanced images. PNET should be considered when the diagnosis of common tumors is not favored by signs on images. CLINICAL TRIAL REGISTRATION STATEMENT: This study was approved by the medical ethics committee of Xiangya Hospital, Central South University. The approval number is 201512538.

Imaging for pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers worldwide due to its aggressiveness and the challenge to early diagnosis. Complete surgical resection is the only curative option, but fewer than 20% of patients have potentially resectable disease at the time of the diagnosis. Radiologists can assess whether PDAC is resectable, borderline resectable, locally advanced or metastatic based on current imaging tests. This review will outline the role of imaging in both the diagnosis and staging of PDAC, with the goal of assisting the multidisciplinary team in tailoring the best treatment for patients.

Tomographic evaluation of Hill-Sachs lesions: is there a correlation between different methods of measurement?

BACKGROUND: Several methods are currently available to evaluate and quantify the glenoid or humeral bone loss; however, none is universally accepted, particularly in the case of Hill-Sachs (HS) lesions. PURPOSE: To establish whether there is correlation among different methods of measuring HS lesions, and to investigate the correlation between glenoid bone loss and the various HS lesion measurements and to assess the inter-observer reliability of such measurements. MATERIAL AND METHODS: We assessed computed tomography (CT) or arthro-CT scans taken from individuals with recurrent anterior glenohumeral dislocation. The scans were independently assessed by two examiners. The parameters assessed were as follows: HS lesion width and depth on the axial and coronal planes, articular arc loss on the axial plane, and percentage of glenoid bone loss on the sagittal plane. RESULTS: Scans from 50 shoulders were assessed. The percentage of articular arc loss and HS lesion width on the axial plane were the only measurements that exhibited strong correlation (r = 0.83; P < 0.001). The values of the correlation coefficient corresponding to HS lesion depth on the coronal plane were the lowest. Most of the measurements exhibited moderate correlation. The inter-examiner reliability was good relative to all measurements except for HS lesion width and depth on the coronal plane, for which it was moderate. CONCLUSION: The measurements of articular arc loss and HS lesion width on the axial plane exhibited strong correlation. The inter-examiner reliability relative to articular arc loss, HS lesion width and depth on the axial plane, and glenoid bone loss was good.

Are the unenhanced and excretory CT phases necessary for the evaluation of acute pyelonephritis?

Background The most widely accepted computed tomography (CT) protocol for diagnosis of acute pyelonephritis (APN) includes at least a pre- and post-contrast scan, which may expose patients to higher doses of ionizing radiation. Purpose To establish the accuracy, reproducibility, and degree of confidence in CT diagnosis of acute pyelonephritis (APN) and urolithiasis using only images obtained during the nephrographic phase. Material and Methods A retrospective study of 100 consecutive patients (88 women; age range, 19-70 years) with clinical and laboratory suspicion of APN and who underwent triphasic abdominal CT scans (non-contrast, nephrographic, and excretory phases) was performed. Two readers first evaluated independently only the nephrographic phase of scans, and, in a second session, the entire study. The diagnostic reference standard was settled by a third experienced radiologist who reviewed all triphasic scans and clinical data. Results The accuracy of only nephrographic phase for diagnosis of APN and urolithiasis was in the range of 90.3-91.78% and 96.27-99.25%, respectively. There was no significant difference in comparison with the triphasic reading (z: -0.4 - 0.2; P = 0.34-0.83). The average degree of confidence for APN also showed no significant variation for both readers ( P = 0.4 and 0.08). Almost perfect inter-observer agreements for the diagnosis of APN (k = 0.86, P < 0.001) and for urolithiasis (k = 0.84, P < 0.001) were observed when considering only the nephrographic phase. Conclusion CT assessment of APN and urolithiasis can be accurately performed using only the late nephrographic phase, with consequent dose reduction.

Neuroimaging of epilepsy.

Imaging is pivotal in the evaluation and management of patients with seizure disorders. Elegant structural neuroimaging with magnetic resonance imaging (MRI) may assist in determining the etiology of focal epilepsy and demonstrating the anatomical changes associated with seizure activity. The high diagnostic yield of MRI to identify the common pathological findings in individuals with focal seizures including mesial temporal sclerosis, vascular anomalies, low-grade glial neoplasms and malformations of cortical development has been demonstrated. Positron emission tomography (PET) is the most commonly performed interictal functional neuroimaging technique that may reveal a focal hypometabolic region concordant with seizure onset. Single photon emission computed tomography (SPECT) studies may assist performance of ictal neuroimaging in patients with pharmacoresistant focal epilepsy being considered for neurosurgical treatment. This chapter highlights neuroimaging developments and innovations, and provides a comprehensive overview of the imaging strategies used to improve the care and management of people with epilepsy.

MRI evaluation of complex renal cysts using the Bosniak classification: a comparison to CT.

PURPOSE: The purpose of this study was to compare the ability of magnetic resonance imaging (MRI) and computed tomography (CT) to discriminate between benign and malignant cystic renal lesions utilizing the Bosniak classification. MATERIALS AND METHODS: We retrospectively searched our Radiological Information System using renal/kidney cysts as entries. The search retrieved 2929 patients and 525 complex renal cysts. After exclusions, 42 complex cysts, from 37 patients, with CT and MRI, up to six months apart, were included. Surgery and pathology report and follow-up of at least 24 months were used as a standard of reference. RESULTS: The mean age of patients was 51.4 years, ranging from 11 to 82 years old. Twenty-nine lesions were classified as Bosniak I, II or II-F by CT and/or MRI and 13 as Bosniak III or IV, by one of the methods. The interobserver agreement for Bosniak classification for CT was 0.87 and 0.93 for MRI. Fifteen lesions had higher Bosniak categories on MRI, included six with change in management. Only two lesions had a higher category on CT, one with change in management. The frequency of malignancy for Bosniak III was 50 % (2/4) for CT and 20% for MRI (1/5), as Bosniak upgrades by MRI resulted in surgery for benign lesions. Both methods had 100 % frequency of malignancy for category 4. CONCLUSION: MRI led to category migration and management change of complex renal cysts in a significant proportion of cases, likely due to its superior soft tissue and contrast resolution. The impact of MRI on detection and outcomes of malignant complex renal cysts still requires further investigation.

Infección del tracto genital superior femenino: revisión pictográfica por tomografía computada según clasificación clínica / Infection of the female upper genital tract: pictorial review by computed tomography according to clinical classification

La infección del tracto genital superior (ITGS) femenino o enfermedad inflamatoria pélvica (EIP) comprende una serie de condiciones inflamatorias del tracto reproductivo femenino. La presentación clínica es variada y la mayoría se presenta como un dolor abdominal de cuadrantes inferiores o dolor pélvico, pudiendo ser incluso difuso y muchas veces manifestarse como un dolor abdominal agudo de difícil diagnóstico. Las formas de presentación clínica y el compromiso anatómico son variados. En 1982 Monif diseñó una clasificación que se basa en el compromiso anatómico de las estructuras afectadas, desde una infección localizada como salpingitis, hasta cuadros más graves con riesgo vital como un absceso tubo oválico (ATO) roto. Las imágenes junto a la clínica forman un pilar fundamental para el diagnóstico y así definir una conducta terapéutica. En el siguiente artículo se presenta una serie de casos con sus principales hallazgos a la tomografía computada (TC) clasificados por los estadios de Monif.

Abstract: Upper genital tract infection (UGTI) or female pelvic inflammatory disease (PID) comprises a number of inflammatory conditions of the female reproductive tract. The clinical presentation is varied and most occur as a lower quadrant abdominal pain or pelvic pain, and may even be diffuse and often manifest as an acute abdominal pain difficult to diagnose. The clinical presentation and anatomic involvement are varied. In 1982 Monif designed a classification based on the anatomical commitment of the affected structures, from a localized infection such as salpingitis, to more serious conditions such as life-threatening ruptured tubo-ovarian abscess (TOA). Images together with case history form a fundamental basis for the diagnosis and so define therapeutic management. In the following article a series of cases are presented with their main findings to the computed tomography (CT) classified according to Monifs staging.

Reconstruction algorithms influence the follow-up variability in the longitudinal CT emphysema index measurements.

OBJECTIVE: We wanted to compare the variability in the longitudinal emphysema index (EI) measurements that were computed with standard and high resolution (HR) reconstruction algorithms (RAs). MATERIALS AND METHODS: We performed a retrospective review of 475 patients who underwent CT for surveillance of lung nodules. From this cohort, 50 patients (28 male) were included in the study. For these patients, the baseline and follow-up scans were acquired on the same multidetector CT scanner and using the same acquisition protocol. The CT scans were reconstructed with HR and standard RAs. We determined the difference in the EI between CT1 and CT2 for the HR and standard RAs, and we compared the variance of these differences. RESULTS: The mean of the variation of the total lung volume was 0.14 L (standard deviation [SD] = 0.13 L) for the standard RA and 0.16 L (SD = 0.15 L) for the HR RA. These differences were not significant. For the standard RA, the mean variation was 0.13% (SD = 0.44%) for EI -970 and 0.4% (SD = 0.88%) for EI -950; for the HR RA, the mean variation was 1.9% (SD = 2.2%) for EI -970 and 3.6% (SD = 3.7%) for EI -950. These differences were significant. CONCLUSION: Using an HR RA appears to increase the variability of the CT measurements of the EI.

Masas mesentericas: evaluación por tomografia computada / Mesenteric masses: computed tomography assessment

The mesentery is a frequent site for abdominal diseases, since it constitutes the intestinal scaffolding and pathway for many structures. Nowadays, computed tomography (CT) is the imaging modality of choice for evaluating mesenteric masses and their origin. An isolated mesenteric mass (primary) is an unexpected and rare tomographic finding in the context of patients with nonspecific clinical signs. The identification of a primary mesenteric mass requires an effort to exelude the possibility of being a secondary source. Thus, knowledge of the spectrum of mesenteric disease (neoplastic, infectious, inflammatory, vascular, traumatic, congenital) and its computed tomographic appearance is the key for proper diagnosis and treatment.

El mesenterio es un sitio frecuente de enfermedades abdominales, ya que constituye el soporte intestinal y una vía de paso para muchas estructuras. Hoy en día, la tomografía computada (TC) es la modalidad de imagen de elección para evaluar las masas mesentéricas y su origen. Una masa aislada (primaria) es un hallazgo tomográfico raro e inesperado de encontrar en el contexto de pacientes con signos clínicos inespecíficos. La identificación de una masa mesentérica primaria requiere un esfuerzo para descartar la posibilidad de un origen secundario. Así pues, el conocimiento del espectro de la enfermedad mesentérica (neoplásicas, infecciosas, inflamatorias, vasculares, traumáticas y congénitas procesos) y su apariencia tomográfica es clave para el diagnóstico y el tratamiento adecuado.

Utilidad de la tomografía computarizada helicoidal en el diagnóstico temprano del cáncer de pulmón / Advantage of helicoid computerized tomography in early diagnosis of lung cancer

Lung cancer is the most lethal malignant neoplasm worldwide. Screening programs using sputum cytology and chest radiography that have been carried out along these past decades have failed to demonstrate any reduction of the mortality rate due to lung cancer. Nowadays, advances in new forms of technology (low-dose CT) have resuscitated the expectant interest in screening programs. This technique has been shown to have a higher sensitivity for small pulmonary nodules, which is the most common presentation of early lung cancer. Preliminary results of early lung cancer detection programs based on low-dose CT are promising: a high proportion of early non-symptomatic, resectable cancers has been demonstrated in asymptomatic smokers. Nevertheless, well-designed, collaborative studies are needed before obtaining definitive conclusions and making general recommendations to screen individuals at high risk

El cáncer de pulmón es la neoplasia con mayor índice de mortalidad en todo el mundo. Los programas de detección temprana de cáncer de pulmón que se realizaron en la década del '70 empleando radiografía simple de tórax y citología de esputo no demostraron una reducción significativa de la mortalidad específica por esta enfermedad. Los avances tecnológicos (tomografía computarizada helicoidal de baja dosis de radiación) han hecho resurgir el interés por los programas de detección sistemática y los resultados obtenidos hasta la fecha son esperanzadores: en fumadores asintomáticos esta técnica permite detectar una proporción alta de tumores resecables en estadio temprano. Sin embargo, es necesario que se desarrollen programas bien diseñados, basados en la colaboración multidisciplinaria, antes de recomendar el cribado del cáncer de pulmón mediante tomografía computarizada torácica de baja dosis de radiación a la población general