Radiologia最新文献

Irreversible Electroporation (IRE) is a non-thermal tumor ablation technique. High-voltage electrical pulses are applied between pairs of electrodes inserted around and/or inside a tumor. The generated electric current induces the creation of nanopores in the cell membrane, triggering apoptosis. As a result, IRE can be safely used in areas near delicate vascular structures where other thermal ablation methods are contraindicated.

Currently, IRE has demonstrated to be a successful ablation technique for pancreatic, renal, and liver tumors and is widely used as a focal therapeutic option for prostate cancer.

The need for specific anesthetic management and accurate parallel placement of multiple electrodes entails a high level of complexity and great expertise from the interventional team is required. Nevertheless, IRE is a very promising technique with a remarkable systemic immunological capability and may impact on distant metastases (abscopal effect).

Prosthetic valve obstruction is a rare but potentially lethal complication. The most frequent causes are thrombus and pannus formation, in the absence of infectious data. Diagnosis is not always easy using cardiac CT scanning and in 46%–85% of cases thrombus and pannus coexist, complicating the diagnosis. A rapid diagnosis is essential to avoid a fatal outcome of this pathology whose mortality, despite correct treatment, is high.

The international literature on university teaching, has insisted on the need to combine a double component in the professional profile of teachers: content knowledge and pedagogical content knowledge.

Regarding the content, the area of knowledge of radiology and physical medicine is made up of different medical specialties, among which are radiodiagnosis, nuclear medicine, radiation oncology, physical medicine and rehabilitation. On the other hand, the pedagogical content knowledge is framed by framework that the Bologna Declaration (1999).

Focusing on radiodiagnosis, the ideal candidates must be professionals in this medical specialty, vocational teachers and people who find in the undergraduate teaching process an opportunity to transmit their knowledge, experiences and values in an entertaining and understandable way for students who are incorporated into medical knowledge.

Objective

To describe the magnetic resonance imaging (MRI) findings for the most common inflammatory and immune-mediated diseases that involve the brainstem.

Conclusion

Inflammatory lesions involving the brainstem are associated with a wide range of autoimmune, infectious, and paraneoplastic syndromes, making the differential diagnosis complex. Being familiar with these entities, their clinical characteristics, and their manifestations on MRI, especially the number of lesions, their shape and extension, and their appearance in different sequences, is useful for orienting the radiological diagnosis.

The fluid-attenuated inversion recovery (FLAIR) sequence forms part of the vast majority of current diagnostic protocols for brain MRI. This sequence enables the suppression of the signal from cerebrospinal fluid, facilitating the detection of disease involving the subarachnoid space. The causes of hyperintensity in the arachnoid space in this sequence can be divided into two main categories: hyperintensity due to disease and hyperintensity due to artifacts. Hyperintensity due to tumors, inflammation, vascular disease, or hypercellularity of the cerebrospinal fluid or hematic contents is well known. However, numerous other non-pathological conditions, mainly due to artifacts, that are also associated with this finding are a potential source of diagnostic errors.

Introduction

Response evaluation of hepatocellular carcinoma (HCC) currently is based on arterial phase enhancement which doesn’t take into microstructural changes in the tumor after trans-arterial chemoembolization (TACE).

Aim

This prospective study was conducted to assess the feasibility and efficacy of intravascular incoherent motion imaging (IVIM) in response evaluation of HCC after TACE.

39 cirrhotic patients with 48 HCC underwent MR imaging 1 week within and 6weeks after TACE. IVIM parameters like Dslow (true diffusion), Dfast (pseudodiffusion), perfusion fraction and ADC were measured prior to and postTACE. The pre and post TACE values in LR-TR (LIRADS – treatment response) nonviable and viable lesions were compared using paired t-tests. ROC curve analysis was done to calculate sensitivity and specificity and propose cut-off values.

Result

Non-viable lesions showed a significant increase in Dslow (1.208 ± 0.581 vs 1.560 ± 0.494, P-value −.0207) and ADC (1.37 ± 0.53 vs 1.65 ± 0.4287, P value .016) after TACE. There was also significant decrease in Dfast (33.7 ± 10.4 vs 23.75 ± 12.13, P value .0005) and f (19.92 ± 10.54 vs 12.9 ± 10.41, P value .012) values after TACE in non-viable lesions compared to viable lesions. The change in true diffusion had the highest AUC (0.741) among IVIM parameters with greater than 0.075 increase between preTACE and postTACE values having a sensitivity and specificity of 81.8% and 60% respectively for complete response.

Conclusion

IVIM imaging is feasible to assess the response in HCC after TACE. True diffusion is more sensitive and specific than apparent diffusion in evaluating the response.

Background and objective

To determine the operational characteristics of salivary gland ultrasound (SGU) in the diagnosis of Sjögren’s syndrome (SS) in a population of colombian patients with dry symptoms.

Materials and methods

Study of diagnostic tests in patients with dry symptoms who consecutively attended the rheumatology consultation (2018–2020). Sociodemographic and clinical data were obtained through a survey, paraclinical and ophthalmological tests, minor salivary gland biopsy, unstimulated salivary flow and SGU (score 0–6 based on De Vita) were done. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values (Stata 15®) were calculated. The receiver operating characteristics (ROC) curve was developed.

Results

102 patients were included (34 SS and 68 non-SS), mean age 55.69 (±11.93) years, 94% women. Positive ultrasound (score of 2 or more) was more frequent in the SS group, (70.6% vs. 22.1%, P < 0.0001). The sensitivity was the same for grade 2 and 3 (70.59%), with a higher specificity (89.71%) for grade 3 (PPV 77.42% NPV 85.92). The ROC curve from the sum of the glands by means of ultrasound was better than those of the independent glands. The ROC curve of the ultrasound presented a greater area under the curve (0.72 [0.61−0.82]) than that of the histological analysis (focus score) (0.68 [0.59−0.78]), P = 0.0252.

Conclusion

Salivary gland ultrasound is a useful and reliable method for the classification of SS. Its use could be considered in the future within the SS classification criteria.

The universally accepted system for the transmission of scientific knowledge in the field of medicine has long been grounded in scientific publications. Social networks can be a useful alternative or complementary method of transmitting this knowledge.

Social networks (e.g., Twitter, Instagram, Facebook, LinkedIn, YouTube, and TikTok) generate educational contents that enable quality training, despite their informality. Each of these networks has strengths and weaknesses that users should know about.

These platforms are free and allow for real-time discussion. They make it easy to incorporate content and to contact experts or access sources of knowledge directly. Aware of their influence, publishers have incorporated metrics to measure the impact of their articles in social networks (Altmetrics).

These networks should be incorporated into departmental training programs immediately. Nevertheless, navigating through social networks is complex, and the hashtag-based system of searching is inefficient, limiting their use in education.

Despite the informality of the knowledge generated on social networks, the importance of these networks as a source of knowledge is growing. Radiology departments must design a strategy for using social networks for education rather than for propaganda, creating well-organized focal groups that search for contents through systematic, filtered review of information, digital repositories, and review sessions and for sharing this knowledge both inside and outside the department. Departments must also implement a strategy for communicating through these networks.

Objectives

To evaluate the relation between the coronary calcium score and the posterior choice of kilovoltage according to radiologists’ criteria in a standard coronary CT angiography protocol to rule out coronary disease.

To quantify the reduction in ionizing radiation after linking kilovoltage to patients’ body mass index in a low-dose protocol with iterative model reconstruction.

To evaluate the image quality and diagnostic performance of the low-dose protocol.

Material and methods

We compared anthropometric characteristics, calcium score, kilovoltage levels, size-specific dose estimates (SSDE), and the dose-length product (DLP) between a group of 50 patients who were prospectively recruited to undergo coronary CT angiography with a low-dose protocol and a historical group of 50 patients who underwent coronary CT angiography with the standard protocol. We correlated these parameters, the number of coronary segments that could not be evaluated with and without temporal padding, the attenuation, and the signal-to-noise ratio in the ascending aorta in the low-dose protocol with excellent imaging quality according to a semiquantitative scale. To calculate the diagnostic performance per patient, we used 24-month clinical follow-up including all tests as the gold standard.

Results

In the standard protocol, the presence of coronary calcium correlated with the selection of high kilovoltage (p = 0.02); this correlation was not found in the low-dose protocol (p = 0.47). Median values of SSDE and DLP were significantly (p < 0.001) lower and less dispersed in the low-dose protocol [9.22 mGy (IQR 7.84–12.1 mGy) vs. 26.5 mGy (IQR 21.3–36.3 mGy) in the standard protocol] and [97 mGy cm (IQR 78–134 mGy cm) vs. 253 mGy cm (IQR 216–404 mGy cm) in the standard protocol], respectively.

The overall quality of the images obtained with the low-dose protocol was considered good or excellent in 96% of the studies. The parameters associated with image quality in a multivariable model (C statistic = 0.792) were heart rate (estimated coefficient, −0,12 [95% confidence interval: −0.2, −0.04]; p < 0.01) and the SSDE (estimated coefficient, −0,26 [95% confidence interval: −0.51, −0.01]; p < 0.05).

The CAD-RADS modifier for a not fully evaluable or diagnostic study was used on two occasions (4%); the final measures for the diagnosis of coronary disease were sensitivity 100%, specificity 94%, and efficacy 94%.

Conclusions

In the standard protocol, the radiologist selects higher kilovoltage for CT angiography studies for patients whose previous calcium score indicates the presence of coronary calcium. In the low-dose protocol, linking kilovoltage with body mass index enables the dose of radiation to be reduced by 65% while obtaining excellent or good image quality in 96% of studies and excellent diagnostic performan