Application of cone beam computed tomography in the diagnosis of root fractures / 口腔疾病防治

@#Cone beam computed tomography (CBCT) has been widely used in various fields of dentistry. The diagnosis of root fractures, especially vertical root fractures (VRFs) with CBCT images, has been a research hotspot since then. Research on this area mainly includes the following five aspects: ① the diagnostic efficiency of CBCT images for root fractures; ② the influence of scanning parameters on the diagnostic accuracy of CBCT images in root fractures, such as scanning field of view, spatial resolution, tube current and tube voltage; ③ whether the application of image postprocessing techniques, especially metal artifact reduction (MAR), can improve the diagnostic accuracy of root fractures after root canal treatment and/or there is a post core in the root canal; ④ establishment and validation of clinical diagnosis model for vertical root fracture; and ⑤ application of artificial intelligence technology and contrast agent in root canals for the diagnosis of CBCT image in root fractures. Compared with periapical radiographs, CBCT images can improve the diagnostic accuracy of root fractures in nonendodontic treated teeth; however, for teeth that have undergone endodontic treatment, the diagnosis of VRF must be combined with clinical signs. Vertical bone resorption in the buccolingual (palatal) direction is a characteristic indicator of VRF. The width of the VRF is an important factor affecting the diagnostic accuracy, but the voxel size used in CBCT scanning is not a necessary factor affecting its diagnostic accuracy; the fracture direction does not affect the diagnostic accuracy of the VRF. Image postprocessing techniques, especially MAR, cannot improve the diagnostic accuracy of VRF and may also reduce the diagnostic efficiency, so they are not recommended for clinical application.

The Effect of Metallic Dental Restorations and Implants in Causing Patient Discomfort and Artefacts During Magnetic Resonance Imaging of the Head and Neck

Context: Patients with metallic dental objects in their oral cavity are often associated with discomfort or artefacts during magnetic resonance imaging (MRI) of the head and neck. Aim: This study was conducted to evaluate the effects of metallic dental objects in causing patient discomfort and artefacts during MRI of the head and neck region. Design: This is an observational study including 538 participants from various specialized MRI centres in Kozhikode. Methods and Material: MRI records of 538 participants who underwent head and neck MRI as a part of their medical treatment were collected. With the help of questionnaire and clinical examination, the type of metallic dental object in the patient’s oral cavity was identified. After examining the MRI images, four categories of artefacts were established. In MRI brain, artefacts in three different sequences were also studied. Statistical Analysis Used: The significance of the difference between proportions was analysed by the Chi?square test. Results: Artefacts were found in 65 cases with metallic dental objects but none of the participants had experienced any kind of discomfort. The artefact formation significantly depended on the type of metallic dental restoration in the patient’s oral cavity. Orthodontic braces and titanium bone plate created severe artefacts in head and neck MRI making interpretation almost impossible. In the MRI brain, diffusion?weighted imaging is most sensitive to artefact followed by fluid?attenuated inversion recovery. Conclusions: Artefacts were found in 65 cases with metallic dental restorations but none of the participants had experienced any kind of discomfort.

Merits and pitfalls of normal saline rehydrated air-dried cervical smears over conventional wet.fixed PAP smears: A comparative study

Background: Cervical Papanicolaou (PAP) smear is the simplest, minimal invasive, and excellent screening method to reduce the female morbidity and mortality due to cervical carcinoma. Immediate alcohol fixation of the cervical smears is required to preserve nuclear details, delay in alcohol fixation leads to air drying artifacts. Rehydrating of the air-dried cervical pap smear with normal saline can help to overcome these artifacts and also have its own advantages. Aims: This study was design to evaluate the effects, merits and pitfalls of normal saline Rehydrated Air-Dried Cervical PAP Smears (RADPS) compared with the Conventional Papanicolaou Smear (C-PAPS). Settings and Design: Comparative study. Methods and Material: Prospectively paired cervical smears of 100 women, who presented to the outpatient department of gynecology of our institute, were prepared. Alcohol fixed smears were labelled as conventional Papanicolaou smear (C-PAPS) and air-dried smears labelled as rehydrated air-dried PAP smears (RADPS). Eight cytomorphological parameters were considered for comparison and analyzed. Statistical analysis used: Chisquare (?2)/Fisher exact test. Results: Clear background with red blood cells (RBC) lysis was noted in 93% of RADPS and 54% of C-PAPS. Cytolysis was observed more in C-PAPS (18%) than in RADPS (08%). Air-drying artifacts observed in 30% of C-PAPS and 08% of RADPS. Cytoplasmic staining (92% of RADPS and 85% of C-PAPS) was superior in RADPS. Cell border, nuclear chromatin, and border were also better appreciated on RADPS as compared to C-PAPS. Statistically significant difference was observed with 3 parameters, i.e., air-drying artifacts, RBC background, and distinct cell borders. Conclusion: Rehydration of air-dried smears can be adopted in regular practice, as an alternative or coupled with conventional wet fixation method to overcome the commonly faced problems of air-drying artifacts, especially in rural screening programs.

Improved ability of demonstrating ocular masses on 3.0 T MR scanner using PROPELLER: a multi-center study / 中华放射学杂志

Objective:To investigate the value of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) in improving ability of demonstrating ocular masses on 3.0 T MR scanner.Methods:This study was a multi-center prospective study involving 6 centers. From July 2018 to January 2020, totally 413 patients with ocular masses from 6 centers were prospectively enrolled, and all of them underwent T 1WI and T 2WI, PROPELLER T 1 FLAIR and T 2WI, and contrast-enhanced scans. The signal intensity of eyelid, vitreous body, lacrimal gland, intraorbital segment of optic nerve, and orbital masses of eyelid, intraocular, lacrimal gland and retrobulbar were measured by two radiologists, and the signal to noise ratio (SNR) and contrast noise ratio (CNR) were calculated. The 5-point scoring method was used to evaluate the motion artefacts, tumor edges and the relationship between the tumor and adjacent structures, and the overall score of image quality was calculated. Paired t-test or Wilcoxon signed rank test was used to compare the image quality between PROPELLER and non-PROPELLER images. Results:The SNR and CNR of PROPELLER T 2WI were higher than those of non-PROPELLER T 2WI (all P<0.001). The SNR and CNR of PROPELLER T 1 FLAIR were lower than those of non-PROPELLER T 1WI (all P<0.05). The scores of artefacts and overall image quality in PROPELLER images were higher than those in non-PROPELLER images (all P<0.001). The tumor edge and the relationship between the tumor and adjacent structures scores of eyelid, intraocular, and lacrimal gland masses in PROPELLER images were higher than those in non-PROPELLER images (all P<0.001),while compared to non-PROPELLER images, retro-global masses in PROPELLER images showed no significant differences (all P>0.05). Conclusion:PROPELLER can reduce ocular motion artefacts, effectively improve image quality and ability of demonstrating anterior (eyelid, intraocular, and lacrimal gland) masses.

Metal Artefact Reduction with Different Transverse Angles of Metal Placement and Gantry Tilt Angulation in Spine CT Imaging

Abstract@#Introduction: Computed tomography (CT) has been widely used for postoperative spine assessment. However, the effectiveness of CT is limited by the presence of multiple artefacts surrounding metal implants. An artefact causes degradation of image quality and obscures the interpretation of spine CT images by a radiologist. The purpose of this study was to evaluate the optimum angle of gantry tilt and metal rod placement which produced the least metal artefact on CT images. Methods: A customised phantom was developed with different transverse angles of metal placement. The transverse angles of metal placement inside the phantom varied at 20°, 30°, 40° and 45°. The phantom was scanned with CT scanner at 0° axial scan angle. It was followed by acquisitions at different gantry tilt angles ranging from −12° to 20°. Quantitative and qualitative assessment by determining the signal-to-noise ratios (SNRs) of the CT images was performed. Results: The severity of the metal streak artefact increased as the metal insertion angles became wider up to 45° due to the widespread of streaking area. The severity of artefacts was reduced with the increment of the gantry tilt angle, which was observed in images acquired at 20°. Conclusion: For the gantry tilt angulation technique, the optimum gantry angle for metal artefact reduction is at the widest angle, which is +20° angulation. Although the gantry tilt technique did not eliminate the metal artefacts, it enabled a significant reduction of metal artefacts and improved image quality.

Pulse Sequence Single Shot Fast Spin Echo for Reducing Motion Artefact on MRI of the Brain

Abstract@# This research was motivated by the increase of brain MRI examinations in emergency medicine. In an emergency, patients are often uncooperative, and they raise motion artefact on the image. Therefore, fast scanning techniques such as pulse Sequence Single Shot Fast Spin Echo (SS-FSE) is required to reduce the artefact. This study was conducted to determine the effectiveness of using SS-FSE technique to minimize motion artefact. Methods: This study was an observational analytic with prospective methods. Scanning was conducted to 16 normal patients (volunteers). Two neuro radiologists retrospectively and independently reviewed all images. Observations used standard diagnostic of brain MR Image by evaluating the anatomical and morphological structure. Results: Based on the results of the analysis of each organ that was assessed, it was obtained that the average of the image for overall organs on the brain; 76% looks sharp, 21% looks moderate (minimum blurred), and 3% looks blurred. Conclusion: SS-FSE technique affects reducing motion artefact due to object movement in MRI brain. The overall image SS-FSE produced has good image quality.

Consistency and percentage agreement of preoperative surface marking of subcutaneous foreign body by colour comet tail artefact with its intra-operative positional findings – A prospective study

Background: Exact surface localization of foreign body is vital prior to its surgical removal. Preoperative localization errors lead to excessive soft tissue exploration, prolonged surgery, increased morbidity and post-surgical complications. Sarkar KN, Mandal SK, Kabiraj P, Mallik R, Gupta DK, Sarkar M. Consistency and percentage agreement of preoperative surface marking of subcutaneous foreign body by colour comet tail artefact with its intra-operative positional findings - A prospective study. IAIM, 2016; 3(6): 32-41. Page 33 Aim: Determination of percentage agreement of preoperative surface marking of subcutaneous foreign body by colour comet tail artefact with its intra-operative positional findings. Materials and methods: Prospective observational study was conducted on 100 patients over duration of eight months from September 2015 to April 2016 at our institution. Preoperative surface marking of foreign body was done using Ultrasound machine PHILIPS HD7 (2.0.1) with 7 MHz linear transducer, Excel mark premium black stamp ink 2oz, Acco smooth steel wire paper clip, Trade mark 45 cm wooden measuring scale and Apsara glass marking pencil. Percentage agreement of preoperative surface marking of subcutaneous foreign body by colour comet tail artefact with its intraoperative positional findings was studied in 100 patients prospectively. All analysis was done by using IBM SSPS statistics 24 and MS Excel. Results: The color tail artifact technique showed percentage agreement of 93.5% for accurate surface marking of vertical line within ≤ 5 mm of actual location and percentage agreement of 92.5% for surface marking of horizontal line within ≤ 5 mm of actual location. Conclusions: Blind surgical procedures of foreign body removal have been replaced by real time ultrasound guided removal under strict sterile conditions in most of the affluent nations. However in developing nations and semi urban places where there is limited and underrated sterilization and disinfection technique, real time ultrasound procedures for foreign body removal remains a challenging option. This study shall suffice to the needs of developing nations and semi urban places with precise preoperative surface localization, advantages of minimal surgical exploration, minimal local tissue injury, reduced patient’s morbidity and no real time ultrasound associated nosocomial infection. The study shall also be helpful with special emphasis to those underserved villages where surgeons still rely on blind foreign body removal procedures, causing massive tissue exploration, increased hospital stay, increased cost of treatment, failure of removal and increased patients morbidity.

Electrocardiographic artefacts mimicking atrial tachycardia resulted in unnecessary diagnostic and therapeutic measures

Electrocardiographic (ECG) artefacts may closely simulate both supraventricular and ventricular tachycardias. We describe a case initially diagnosed as rapid atrial fibrillation, based on 12-lead surface ECG (especially the limb leads) and monitor tracing. The arrhythmia was resistant to beta blockers. Because of the at times apparently regular rhythm, an esophageal ECG recording was performed, and adenosine was administered. When the presumed atrial fibrillation terminated after sodium pentothal was administered while preparing for electrical cardioversion, the oesophageal ECG recordings and the ECGs during adenosine administration were reviewed. An ECG artefact diagnosis was suspected, and then confirmed, during relapse of the "arrhythmia," with simple palpation of the radial pulse and cardiac auscultation.

Non Cerebral Activity in Patients of Schizophrenia: EEG Study.

Non Cerebral Activities (NCA) can mimic almost any kind of cerebral electrical activity and lead to serious misinterpretation if artefact periods remain in the recording. We focused on NCA detection in EEG of Patients with Schizophrenia. Out of 35 schizophrenia patients the presence of muscle and eye blink artefacts were higher in there percentages i.e. 86% and 92%. Fifteen patients (42.8%) reported as EEG of doubtful significance, which is higher in psychiatric patient’s then general population of epileptics.

Heat induced morphological changes in the brain.

In severe conflagration the terminal state of the body often does not reflect the condition at the time of death. Some-times death might have occurred before any heat reaches the body and the death might have been caused by inhalation of smoke. It is difficult or rather impossible for the forensic expert to determine the extent of ante-mortem damage caused by flames. The classical distinction of “red flare or vital reaction” are usually absent in such cases. Destruction of the victim by fire is one of the oldest methods used by murderers to conceal their crime, and hence every death by burning require the most meticulous medico-legal scrutiny. Here we report an unusual cases of heat induced morphological changes in brain in a 60 years male, who was addicted to alcohol and smoking and found burnt on his bed in a locked room from inside. Typical vital reaction was not appreciable anywhere on the body so as to frame the opinion in favour in ante-mortem burns but on of dissection of skull certain unusual gross pathological finding was observed which helped in framing the opinion in favour of “Death due to accidental antemortem flame burns”.

Postmortem burns: An artefact due to transportation.

An artefact is any change caused or feature introduced in a body after death (accidentally or physiologically unrelated finding to the natural state of the body) that is likely to lead to misinterpretation of medico legally significant ante mortem findings. Artefacts due to burns are usually attributed to prolonged exposure of flame (in cases of death due to burns), Or else due to attempts made to burn a body after homicide with the object of concealing the crime. Post mortem artefact due to burns in the present case, its implication and proposed mechanism are discussed in detail due to rarity of its kind.