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Abstract This study aimed to assess the effect of the MAR tool on the expression of artefacts in different regions of a tooth restored with different types of metal posts. Alveolar sockets (anterior, and posterior region) of a mandible and an unirradicular tooth were used. Cone beam computed tomography scans of the tooth without a metal post, and with cobalt-chromium (Co-Cr), nickel-chromium (Ni-Cr), or silver-palladium (Ag-Pd) were individually obtained, with 2 MAR conditions: disabled, and enabled. In an axial reconstruction, lines of interest (LOIs) were set around the canal: 4 in oblique (mesiobuccal, distobuccal, mesiolingual, distolingual) directions, and 4 in orthogonal (mesial, distal, buccal, lingual) directions. Beam-hardening artefacts expression was determined by calculating the difference in the mean of gray values (DMGV) between the experimental and control groups for each LOI. There was no significant difference in the DMGV values between "without MAR" and "with MAR" for any LOI, in neither anterior nor posterior mandible (p>0.05), for the Ni-Cr and Co-Cr groups. For the Ag-Pd, significant differences in the DMGV values were observed between "without MAR" and "with MAR" for most LOIs (p<0.05), mainly in oblique directions in the anterior region, and mesio-distal direction in the posterior region. MAR acted mostly in hypodense artefacts (negative DMGV). The effectiveness of the MAR tool of the OP300 CBCT unit varied according to the post material tested. It was effective in reducing the expression of artefacts raised by the Ag-Pd post, mainly in the tooth regions affected by hypodense artefacts, regardless of the mandibular region.
Resumo O objetivo nesse estudo foi avaliar o efeito da ferramenta de redução de artefato (FRA) na expressão de artefatos em diferentes regiões de um dente restaurado com diferentes tipos de pinos metálicos. Foram usados alvéolos (regiões anterior e posterior) de uma mandíbula e um dente unirradicular. Imagens de tomografia computadorizada de feixe cônico do dente sem pino metálico intracanal e com pinos de cobalto-cromo (Co-Cr), níquel-cromo (Ni-Cr) ou prata-paládio (Ag-Pd) foram individualmente obtidas, com 2 condições de FRA: desativada e ativada. Em uma reconstrução axial, linhas de interesse (LOIs) foram definidas ao redor do canal: 4 em direções oblíquas (mésio-vestibular, disto-vestibular, mésio-lingual e disto-lingual) e 4 em direções ortogonais (mesial, distal, vestibular e lingual). A expressão dos artefatos de endurecimento do feixe foi determinada pelo cálculo da diferença na média dos valores de cinza (DMVC) entre os grupos experimental e controle para cada LOI. Não houve diferença significativa nos valores de DMVC entre as condições "sem FRA" e "com FRA" para nenhuma das LOIs, nem na região anterior nem na região posterior da mandíbula (p>0,05), para os grupos Ni-Cr e Co-Cr. Para o Ag-Pd, diferenças significativas nos valores de DMVC foram observadas entre "sem FRA" e "com FRA" para a maioria das LOIs (p<0,05), principalmente nas direções oblíquas na região anterior, e na direção mesio-distal na região posterior. A FRA atuou principalmente em artefatos hipodensos (DMVC negativos). A eficácia da FRA disponível no aparelho de TCFC OP300 variou de acordo com o material do pino testado. Ela foi efetiva na redução da expressão de artefatos originados por pinos de Ag-Pd, principalmente nas regiões do dente afetadas por artefatos hipodensos, independentemente da região mandibular.
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ABSTRACT Optical coherence tomography is often used for detection of glaucoma as well as to monitor progression. This paper reviews the most common types of artifacts on the optical coherence tomography report that may be confused with glaucomatous damage. We mainly focus on anatomy-related artifacts in which the retinal layer segmentation and thickness measurements are correct. In such cases, the probability maps (also known as deviation maps) show abnormal (red and yellow) regions, which may mislead the clinician to assume disease is present. This is due to the anatomic variability of the individual, and the normative database must be taken into account.
RESUMO A tomografia de coerência óptica é frequentemente usada para detectar glaucoma, bem como para monitorar a progressão. Este artigo analisa os tipos mais comuns de artefatos no relatório de tomografia de coerência óptica que podem ser confundidos com danos glaucomatosos. Nós nos concentramos principalmente nos artefatos relacionados à anatomia em que a segmentação da camada da retina e as medidas de espessura estão corretas. Nesses casos, os mapas de probabilidade (também conhecidos como mapas de desvio) mostram regiões anormais (vermelho e amarelo), o que pode induzir o clínico em erro ao supor que a doença está presente. Isto se deve à variabilidade anatômica do indivíduo, e o banco de dados normativo deve ser levado em conta.
Subject(s)
Humans , Glaucoma/diagnostic imaging , Artifacts , Tomography, Optical Coherence/methods , Posture , Retina/diagnostic imaging , Torsion Abnormality , Head Movements , Diagnostic Errors , Eye Movements , Fovea Centralis , Nerve Fibers/pathologyABSTRACT
ABSTRACT: New microcirculatory imaging techniques allowed direct observation of microcirculation at the bedside. This study presents a new device that assists the operator with the unprecedented Hands Free technique. To this end, a replica of Handheld Vital Microscopy was developed to simulate the method of capturing the image in the sublingual area, the most used site to assess microcirculation in critically ill patients. We achieved a reduction in the displacement of micros cope replica with a Hands Free method. The immediate consequence is an increase in the stability of HVM replica by 75 times, or more, over the current 4 seconds, during its contact with the sublingual tissue. The device also offers better control of th e pressure of the tip of the HVM replica over the sublingual area. The results demonstrated that the Hands Free technique, operating in the same sublingual area for 900 seconds, should allow for future research aimed at therapeutic maneuvers in patients with serious illnesses.
RESUMEN: Las nuevas técnicas de imagen microcirculatoria permitieron la observación directa de la microcirculación junto a la cama del paciente. Este estudio sin precedentes presenta un nuevo dispositivo que ayuda al operador con la técnica manos libres. Con este fin, se desarrolló una réplica de la Microscopía Vital Portátil para simular el método de captura de la imagen en el área sublingual, el sitio más utilizado para evaluar la microcirculación en pacientes críticos. Logramos una reducción en el desplazamiento de la réplica del microscopio con el método de manos libres. La consecuencia inmediata es un aumento en la estabilidad de la réplica de HVM en 75 veces, o más, durante los 4 segundos actuales, durante su contacto con el tejido sublingual. El dispositivo también ofrece un mejor control de la presión de la punta de la réplica de HVM sobre el área sublingual. Los resultados demostraron que la técnica de manos libres, que opera en la misma área sublingual durante 900 segundos, debería permitir futuras investigaciones destinadas a maniobras terapéuticas en pacientes con enfermedades graves.
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@#Any metallic object within the CT scanning field can produce metal artefacts, which will degrade the diagnostic image quality. Previous methods described for quantifying this kind of artefacts were complicated and difficult to reproduce. The purpose of this study was to introduce a new rapid method for quantifying the artefacts produced in craniofacial CT images. This is an in-vitro experimental study. Four different compositions of orthodontic brackets were bonded consecutively in the tooth surfaces of a cadaveric skull head. All scans were performed by a single operator using the same CT machine followed by a standard scanning protocol. Artefact intensity for all data sets was quantified by following a modified method with a freely available open-source software ImageJ. All datasets were duplicated where metal artefacts were quantified according to the previous conventional method. Statistical analysis included independent samples t-test for validation and intraclass correlation coefficient (ICC) with a 95% confidence interval for both intra- and inter-examiner reliability. The modified method of measuring artefact score exhibited excellent intra (0.997–0.941) and inter-rater (0.996–0.905) reliability. In addition, no significant difference (p = 0.072) of mean artefact score was noted between the groups measured by the modified method and the conventional method. This modified method for measuring the artefact intensity is valid and reliable.
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Background: An enormous number of artefacts are encountered in magnetic resonance imaging (MRI) which jeopardize the image quality. A comprehensive knowledge of the sources and the remedial measures needed is pivotal to enhance and optimize the image quality in magnetic resonance imaging (MRI). Objectives: The primary objectives of the study were to identify different MRI artefacts, to find the reason/cause of these artefacts and to find methods for correction of these artefacts. Materials and methods: This was a prospective study which included all the patients that were referred to our department for various MRI examinations. The study was carried at 1.5 tesla Magnetom Avanto Siemens, Germany. All the MRI examinations were performed by trained technologist in presence of an experienced radiologist. The MR images acquired were studied for the presence of any artefacts during the performance of MRI examination, the MR parameters at which the artefacts appeared and subsequently the remedial measures undertaken. Results: A total of 209 patients comprising 95 females and 114 males, referred to our department for MRI examinations of various body parts were studied. The commonest artefact observed was motion artefact in 43 (20.6%) patients followed by susceptibility artefact and aliasing artefact. Less common artefacts observed were chemical shift artefact, herring bone artefact, Gibb’s artefact, Moiré fringe artefact, zipper artefact and magic angle phenomenon. Arshed Hussain Parry, Abdul Haseeb Wani, Abdul Momin Jan, Tariq Ahmad Gojwari. Artefacts in magnetic resonance imaging (MRI) and their remedies. IAIM, 2019; 6(4): 122-130. Page 123 Conclusion: Thorough understanding of the sources of magnetic resonance imaging (MRI) artefacts and the mechanism of their production enables
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The incidence of prostate cancer has been gradually increasing in the world. Checking the serum prostate-specific antigen (PSA) level and a digital rectal examination (DRE) are the gold standards for prostate cancer screening. Prostate gland is divided into four zones, the peripheral zone (PZ), transitional zone and central zone and anterior nonglandular fibromuscular stroma. Prostate is divided into minimum 16 and optionally 27 regions of interest as per European consensus meeting. Until recently, most professionals have been skeptical that magnetic resonance imaging (MRI) could be used on a widespread basis to diagnose or stage prostate cancer with any degree of reliability, and therefore help with making treatment decisions. The aim of the present study was to study diagnostic value of mpMRI of prostate in cases of raised PSA but with negative biopsy. The present study was carried out in the post graduate department of Radiodiagnosis and imaging Govt. Medical College Srinagar over a period of one year from May 2016 to April 2017. All patients with negative prostatic biopsy were evaluated on Siemens 3 tesla MRI scanner. All patients underwent initial T1W scanning to look for any evidence of hemorrhage and patients having hemorrhage due to previous biopsy were also excluded from study or their study was deferred until hemorrhagic artifacts disappear. After proper case selection patients were subjected to detail Multiparametric MRI (mpMRI) for prostate 6-8 weeks period was given from previous biopsy time to MRI study and cases with hemorrhage on T1 weighted sequence were either excluded from study or their study was deferred till resolution of Aijaz Ahmad Hakeem, Irshad Mohiuddin, Tanvir Iqbal. Multi-parametric 3-Tesla MRI evaluation of prostate in cases with negative prostatic biopsy with raised PSA levels - A tertiary care hospital study. IAIM, 2018; 5(6): 5-13. Page 6 haemorrhage. The conclusion of the present study was that Mp-MRI prior to repeat biopsies can improve the detection rate of clinically significant PCa and allow for a more accuracy in prostate disease diagnosis.
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Diagnostic errors can occur when physicians rely solely on computer electrocardiogram interpretation. Cardiologists often receive referrals for computer misdiagnoses of atrial fibrillation. Patients may have been inappropriately anticoagulated for pseudo atrial fibrillation. Anticoagulation carries significant risks, and such errors may carry a high cost. Have we become overreliant on machines and technology? In this article, we illustrate three such cases and briefly discuss how we can reduce these errors.
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Objetivo: Establecer la utilidad de la resonancia magnética (RM) en pacientes con reemplazo total de rodilla (RTR) dolorosa tras la aplicación de un protocolo optimizado y determinar en qué medida estos hallazgos modifican la conducta terapéutica. Materiales y métodos: Se analizaron con protocolo optimizado las RM de 15 pacientes con RTR dolorosa, realizadas entre marzo de 2013 y febrero de 2014. La evaluación fue hecha por un especialista en musculoesquelético y los hallazgos fueron registrados. Resultados: De nuestra población, el 74% eran mujeres y la media de edad fue de 74 +/ - 7 años. Se identificaron posibles causas de dolor en el 80% de los casos y se modificó la conducta médica en el 33%. Se encontró líquido articular en el 93% y signos de sinovitis en el 33%. Los tendones rotuliano, cuadricipital y poplíteo se vieron correctamente en el 77%, 92% y 69%, respectivamente; mientras que los ligamentos colaterales medial y lateral fueron visibles en el 46% y 54%, respectivamente. Discusión: Si bien hay publicaciones con diferentes prevalencias de sinovitis y demás hallazgos, la mayoría ha demostrado que la RM de rodilla con un protocolo optimizado permite generar cambios en la conducta terapéutica. A su vez, el método siempre ha visualizado los ligamentos y tendones de la rodilla con un éxito similar al de nuestro trabajo. Conclusión: Aun careciendo de softwares comerciales específicos que reduzcan el artificio metálico, la aplicación de un protocolo optimizado logra identificar hallazgos que guían el tratamiento y permite evaluar las estructuras ligamentarias.
Objective: To establish the usefulness of magnetic resonance (MR) in patients with total knee replacement (TKR) pain after applying an optimised protocol, and to determinate which of the findings influence medical decision. Materials and methods: Fifteen patients suffering knee pain after TKR were studied using an optimised MR examination protocol from March 2013 to February 2014. The MR was interpreted by a musculoskeletal radiologist and findings were registered. Results: Out of the 15 patients, 74% were female. Mean age was 74 +/ - 7 years. The cause of pain was identified in 80% of the cases, and the medical decision was changed in 33%. Increased intra-articular fluid was seen in 93%, and signs of synovitis in 33%. The patellar, quadricipital, and popliteal tendons were correctly assessed in 77%, 92%, and 69% of patients, respectively, while the tibial and the fibula collateral ligaments were correctly assessed in 46% and 54% of patients, respectively. Discussion: Despite other articles showing a different prevalence of synovitis and MR findings, most of them showed that an optimised protocol impacted on clinical care. Also, most of the adjacent anatomical structures were successfully observed, as in our case. Conclusion: Even in the absence of metal reduction tailored sequences, an optimised protocol manages to diagnose conditions that alter clinical decisions and allows the identification of adjacent anatomical structures.
Subject(s)
Humans , Male , Female , Magnetic Resonance Spectroscopy , Arthroplasty, Replacement, Knee , Knee Prosthesis , Retrospective Studies , Knee/diagnostic imagingABSTRACT
Background: Supraglottic airway devices (SADs) are routinely being used in Magnetic Resonance Imaging (MRI) suite but there is a lacuna in the literature regarding their in vivo comparison. The study was planned to compare two of the commonly used SADs, cLMA and i-gel in children undergoing MRI. Methods: A prospective randomized study conducted in a tertiary care teaching hospital. 50 ASA I or II children (aged 12 to 48 months) scheduled for MRI brain were included. Patients were randomly assigned to cLMA or i-gel group (25 patients in each group). We assessed a number of attempts, insertion time, oropharyngeal leak, MRI artifacts and post-procedure complications. Results: Time taken for insertion in i-gel group was significantly lower as compared to cLMA group (p=0.006). Artefacts were observed in all the patients in cLMA group and none in i-gel group, which was extremely significant statistically. Conclusion: i-gel is superior to cLMA for MRI as it does not have any ferromagnetic constituent.
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Hay una gran variedad de artefactos en imágenes que se producen por la interacción entre los equipos y el paciente. Reconocerlos es importante, ya que pueden inducir informes erróneos o encubrir una patología. Por ello, una vez detectados, es necesario emplear técnicas para su eliminación. Describimos los artefactos más frecuentes en tomografía computada y resonancia magnética.
A wide variety of artefacts are observed in diagnostic imaging. They are caused by the interaction between the equipment and the patients. To recognise them is important, because they can induce pitfalls in the reports or mask some disease. Once they have been detected, it is necessary to apply techniques in order to elimínate them. A description is presented of the most common artefacts in computed tomography and magnetic resonance imaging.
Subject(s)
Humans , Male , Female , Magnetic Resonance Spectroscopy , Tomography, X-Ray Computed , Artifacts , Diagnostic Imaging , Diagnostic Techniques and ProceduresABSTRACT
We report on a case of amniotic fluid embolism with air embolism during the labor of multigravida. The patient complained about sudden dyspnea during labor. She turned pale, got disturbed and broke out in a cold sweat. Blood pressure was unmeasurable; peripheral pulse could not be felt. Immediately intensive CPR was performed. The condition of the patient got worse after a short time of improvement. The patient died after about 9 hours. Amniotic fluid contents could be found in the victim 's pulmonary microvasculature. The cause of death was ruled as an amniotic fluid embolism. However, Air embolism was detected during the autopsy. We considered that postmortem air embolism was produced by external cardiac compression. External cardiac compression (ECC) with respiratory care is usually done during emergency conditions. However, ECC produce many artefacts such as sternal or rib fracture, direct cardiac injury, pulmonary injury, fat embolism, liver injury so on. Air embolism is rare artefact. The mechanism of air passing from the venous to systemic circulation in our case remains speculative. However, intense ECC itself with its underlying thoracic pump mechanism has to be considered as contributing to the transport of air from the venous to the arterial side of circulation. In situation of CPR was performed, It must be differentiated from the antemortem air embolism by thorough history taking.