Presurgical Planning Research Articles

Radiographic imaging in relation to the mandibular third molar: a survey among oral surgeons in Sweden

ObjectivesTo query the experience of oral surgeons concerning referral routines and preferences for radiographic imaging modality before surgical removal of mandibular third molars and investigate factors that influence imaging modality preferences.Materials and methodsMembers of the Swedish Association of Oral and Maxillofacial Surgeons (n = 280) were invited to participate in a web-based digital survey concerning their experiences and use of three imaging modalities in pre-surgical assessment of mandibular third molar removal. The survey comprised multiple-choice questions and four cases depicted in images; respondents reported whether they would supplement the cases with other images and, if so, from which modality.ResultsThe response rate was 64%. Panoramic radiographs were most commonly used in pre-surgical planning (response options: always or often), significant difference between professions (p = 0.039), and considered to facilitate treatment planning (87%), as was CBCT (82%); for 51%, CBCT reduced post-operative complications. Preferred modality for localizing the mandibular canal was fairly evenly distributed and for non-complex case, significant difference between subgroups of OMFS surgeons was found (p = 0.003) as to preference for intraoral radiographs.ConclusionsA majority of respondents received a report within 2 weeks of their referral for CBCT and would read the report and view the images before surgery. Image modality preference differed depending on case complexity, with a greater perceived need for CBCT. Profession and practical experience affected choice.Clinical relevanceChoice of imaging modality in mandibular third molar assessment is also important from dose delivery and social economy standpoints.

Rhinoplasty Pre-Surgery Models by Using Low-Dose Computed Tomography, Magnetic Resonance Imaging, and 3D Printing.

Rhinoplasty and surgical reconstruction of cartilaginous structures still remain a great challenge today. This study aims to identify an imaging strategy in order to merge the information from CT scans and magnetic resonance imaging (MRI) acquisitions and build a 3D printed model true to the patient’s anatomy, for better surgical planning. Using MRI, information can be obtained about the cartilage structures of which the nose is composed. Ten rhinoplasty candidate patients underwent both a low-dose protocol CT scan and a specific MRI for characterization of nasal structures. Bone and soft tissue segmentations were performed in CT, while cartilage segmentations were extrapolated from MRI and validated by both an expert radiologist and surgeon. Subsequently, a 3D model was produced in materials and colors reproducing the density of the three main structures (bone, soft tissue, and cartilage), useful for pre-surgical evaluation. This study has highlighted that the optimization of a CT and MR dedicated protocol has allowed to reduce the CT radiation dose up to 60% compared to standard acquisitions with the same machine, and MR acquisition time of about 20%. Patient-tailored 3D models and pre-surgical planning have reduced the mean operative time by 20 minutes.

CT-angiography and Doppler ultrasonography in the evaluation of carotid artery stenosis: a comparative study

Abstract Background and purpose Management of carotid artery stenosis is primarily based on the degree of luminal narrowing. The aim of this study is to compare the results of carotid doppler ultrasound (US) and CT angiography (CTA) for grading of carotid stenosis and for plaque characterization in symptomatic patients. Methods This is a cross sectional study with a total number of 35 consecutive patients having 70 carotid arteries for comparison. Grading of carotid stenosis was based on the NASCET criteria for CTA and the carotid consensus panel criteria for US. Each investigator was blinded to the results of the other modality. Results The majority of patients were aged from 60 to 69 years with male to female ratio of 3:2. Males were more commonly affected than females. The most common presenting symptom was recent stroke. Risk factors included; diabetes mellites and hypertension. Atherosclerotic ischemic heart disease was a present association. The carotid bulb and proximal ICA were the most common location for carotid plaques. Kappa analysis with 95 % confidence intervals (CIs) was utilized to determine US – CTA agreement. Both modalities showed overall good agreement (kappa = 0.63) and the concordance was better for moderate and higher grades of stenosis than for non-significant stenosis. The disagreement did not exceed one grade difference in our study sample. There was also good agreement as regards plaque morphology, while CTA was more sensitive than US in the detection of calcifications and plaque ulceration. Conclusion Doppler ultrasound when performed by an experienced sonographer can be used as a reliable first line modality for carotid stenosis grading and to categorize patients as medical and potentially surgical cases. CTA can be used as a confirmatory method for patients with borderline stenosis, for presurgical planning and for patients with suspected stenosis of the intracerebral circulation.

Utility of ECG-Gated CTA for Detecting and Classifying Coronary Artery Involvement in Patients With Type A Aortic Dissection and Sinus of Valsalva Involvement.

BACKGROUND. Extension of type A aortic dissection (TAAD) from the sinus of Valsalva (SV) into the coronary arteries is associated with a poor prognosis and requires direct coronary repair or coronary artery bypass grafting (CABG) depending on the extent of involvement. OBJECTIVE. The purpose of this study was to assess the diagnostic performance of ECG-gated aortic CTA with surgical findings as the reference for detection and classification of coronary artery involvement in patients with TAAD involving the SV. METHODS. This retrospective study included 112 patients who underwent preoperative ECG-gated aortic CTA that showed TAAD with SV involvement. Two radiologists independently reviewed CTA images for right coronary artery (RCA) and left coronary artery (LCA) involvement. Involvement was classified according to a previously described system as type A (coronary ostial dissection), B (dissection with coronary false channel), or C (complete detachment from aortic root with dissection encircling the coronary artery). The diagnostic performance of CTA was calculated with surgical findings as the reference; interreader agreement was assessed; and surgical interventions were summarized. RESULTS. At surgery, the RCA was uninvolved in 33 patients and had type A involvement in 45, type B involvement in 19, and type C involvement in 15 patients. The LCA was uninvolved in 70 patients and had type A involvement in 34 patients, type B involvement in eight patients, and type C involvement in no patient. For the two readers, sensitivity in making the diagnosis in the RCA was 86.7% and 91.1% for type A, 79.0% and 89.5% for type B, 86.7% and 93.3% for type C, and 97.5% and 98.7% for any involvement. Sensitivity for the LCA was 85.3% and 91.2% for type A, 87.5% and 100% for type B, and 100% for any involvement. Specificity for the RCA was 94.0% and 97.0% for type A, 95.7% and 96.7% for type B, 96.9% and 96.9% for type C, and 93.9% and 97.0% for any involvement. Specificity for the LCA was 96.2% and 98.7% for type A, 96.2% and 97.1% for type B, and 97.1% and 98.6% for any involvement. Interreader agreement for types of involvement ranged from a kappa value of 0.85 to 0.96. The most common interventions were aortic repair for SV involvement alone (55.7-63.6%), coronary artery repair for types A and B involvement (53.3-87.5%), and CABG for type C involvement (86.7%). CONCLUSION. ECG-gated CTA has high diagnostic performance in the detection and classification of coronary involvement in TAAD with SV involvement. CLINICAL IMPACT. CTA findings may help guide presurgical planning for patients with TAAD.

Presurgical Planning with Open-Source Horos Software for Superficial Brain Arteriovenous Malformations

Surgical planning for treating brain arteriovenous malformations (bAVMs) is challenging because it entails visualizing 3-dimensional (3D) relationships between the nidus, its feeding and en passage arteries, and draining veins. Surgical experience in developing the capacity to mentally visualize pathological bAVM angioarchitecture could be complemented by this software, and thus potentially lower the steep learning curve for understanding complex bAVM angioarchitecture. We evaluated the clinical application of freely available online 3D reconstruction software in facilitating visualization of AVM angioarchitecture for presurgical planning. Preoperative Digital Imaging and Communications in Medicine magnetic resonance imaging/magnetic resonance angiography images of 56 superficial bAVMs from 2013 to 2018 were processed using open-source software Horos. 3D rendered images were compared with the surgical view to evaluate software accuracy and determine its value as a preoperative tool. 3D reconstructed images were compared with intraoperative recordings. A useful image identifying both the main feeding artery and draining vein was achieved in 35 of 56 cases (62.5%). Reconstructions of small AVMs (nidus ≤2 cm) and those located within the temporal or cerebellar cortex were less useful due to soft tissue artifacts. Frontal and parietal lobe lesions had significantly higher rates of identifying feeding arteries and draining veins (P < 0.05). Presurgical planning for resection of superficial bAVMs using Horos software allows for a comprehensive 3D analysis of the bAVM angioarchitecture. This technique is most useful for frontal and parietal lobe lesions, and aids the surgeon in formulating an optimal surgical strategy. The 3D reconstruction of the brain surface offers a surgical map not influenced by brain shift.

A systematic review of the clinical value and applications of three-dimensional virtual reconstructions in renal tumors.

Three-dimensional (3D) virtual reconstruction (VR) in the medical sciences has emerged as a novel, exciting and effective tool, with promising results for patients, trainees, and even experienced surgeons. The purpose of this review is to summarize the information on the clinical value and applications of 3D VR in renal tumors published in the last ten years. A literary search of PubMed-MEDLINE databases was performed to identify studies reporting the clinical application and usefulness of 3D VR models in renal tumors. Thirty-seven studies were found to meet the selection criteria and were included in the analysis. Most studies have provided a quantitative assessment focused on the accuracy of 3D VR models in replication of anatomy and renal tumor, on measuring 3D tumor volume and on the clinical value and utility of 3D VR in pre-surgical planning and simulation of renal procedures, with significant reductions of intraoperative complications. Fourteen studies provided a qualitative assessment of the usefulness of 3D VR models, with results showing an improved patient understanding of renal anatomy and pathology, improved undergraduate and postgraduate urology education. Moreover, 3D printing technology is a novel technique, and we are currently in the dynamic era, expanding into new surgical nephron-sparing procedures and the development of printed kidneys for transplantation.

Evaluation and Comparison of Self-Made and Commercial Calibration Markers for Radiographic Magnification Correction in Veterinary Digital Radiography.

Magnification error is always present in radiography and calibration is necessary, if high accuracy is required in pre-surgical planning. The goal of this study was to verify the use of self-made markers and calibration techniques and to establish guidelines for magnification correction. We evaluated and compared spherical and linear markers of different sizes with focus on practicability, accuracy and precision. Markers were placed on foam pads or attached to flexible arms. Vertical marker deviation of 1 cm from the anatomical reference point corresponded to ∼1% of magnification error in our setting. Marker placement along the horizontal plane showed no significant magnification in the periphery of the radiograph. All markers showed good accuracy and the commercial spherical marker with a flexible segment arm had the best results regarding practicability. Our study suggests that marker type is not solely responsible for usability and accuracy but also the type of fixation. In the absence of a calibration marker, calculation of the magnification factor using a measurement tape during radiography is equally reliable. Use of a fixed averaged calculated calibration factor showed poor agreement compared with the marker calibration, probably due to variability in size of the animals. In conclusion, if precision matters, use of a calibration marker, which could be purchased or self-made, is advised.

Early Experience With Virtual and Synchronized Augmented Reality Platform for Preoperative Planning and Intraoperative Navigation: A Case Series.

BACKGROUNDVirtual reality (VR) allows for presurgical planning. Intraoperatively, augmented reality (AR) enables integration of segmented anatomic information with neuronavigation into the microsurgical scene to provide guidance without workflow disruption. Combining VR and AR solutions may help guide microsurgical technique to improve safety, efficiency, and ergonomics.OBJECTIVETo describe a VR/AR platform that provides VR planning and intraoperative guidance via microscope ocular injection of a comprehensive AR overlay of patient-specific 360°/3D anatomic model aligned and synchronized with neuronavigation.METHODSCustom 360° models from preoperative imaging of 49 patients were utilized for preoperative planning using a VR-based surgical rehearsal platform. Each model was imported to SyncAR, the platform's intraoperative counterpart, which was coregistered with Medtronic StealthStation S8 and Zeiss or Leica microscope. The model was injected into the microscope oculars and referenced throughout by adjusting overlay opacity. For anatomic shifts or misalignment, the overlay was reregistered via manual realignment with known landmarks.RESULTSNo SyncAR-related complications occurred. SyncAR contributed positively to the 3D understanding of patient-specific anatomy and ability to operate. Preoperative planning and intraoperative AR with 360° models allowed for more precise craniotomy planning and execution. SyncAR was useful for guiding dissection, identifying critical structures including hidden anatomy, understanding regional anatomy, and facilitating resection. Manual realignment was performed in 48/49 surgeries. Gross total resection was achieved in 34/40 surgeries. All aneurysm clipping and microvascular decompression procedures were completed without complications.CONCLUSIONSyncAR combined with VR planning has potential to enhance surgical performance by providing critical information in a user-friendly, continuously available, heads-up display format.

Radiographic template used to facilitate the alignment of digital scans to computed tomography scans with extensive beam hardening artifacts

Endosteal dental implants have shown to be an excellent long-term resource for the treatment of edentulism. 1 Malo P. de Araujo Nobre M. Lopes A. The use of computer-guided flapless implant surgery and four implants placed in immediate function to support a fixed denture: preliminary results after a mean follow-up period of thirteen months. J Prosthet Dent. 2007; 97: S26-S34 Abstract Full Text Full Text PDF PubMed Scopus (144) Google Scholar For decades, restorative-driven implant placement has been considered the norm for patient care, 2 Van Assche N. Vercruyssen M. Coucke W. Teughels W. Jacobs R. Quirynen M. Accuracy of computer-aided implant placement. Clin Oral Implants Res. 2012; 23 Suppl 6: 112-123 Crossref PubMed Scopus (169) Google Scholar ,3 Garber D.A. The esthetic dental implant: letting restoration be the guide. J Am Dent Assoc. 1995; 126: 319-325 Abstract Full Text PDF PubMed Scopus (103) Google Scholar and careful presurgical planning by using accurate diagnostic elements is widely recognized as a requirement for predictable, esthetic, and functional implant placement. 3 Garber D.A. The esthetic dental implant: letting restoration be the guide. J Am Dent Assoc. 1995; 126: 319-325 Abstract Full Text PDF PubMed Scopus (103) Google Scholar

V04-03 A GUIDE TO UTILIZING IRIS, A SEGMENTED 3D MODEL, TO IMPROVE SURGICAL PLANNING AND PATIENT OUTCOMES DURING ROBOTIC PARTIAL NEPHRECTOMY

INTRODUCTION AND OBJECTIVE:IRIS is an interactive, three-dimensional (3D) anatomical model system designed to assist surgeons with pre-surgical planning and provide a reference intraoperatively. Ge...

Real-time augmented reality application in presurgical planning and lesion scalp localization by a smartphone.

A smartphone augmented reality (AR) application (app) was explored for clinical use in presurgical planning and lesion scalp localization. We programmed an AR App on a smartphone. The accuracy of the AR app was tested on a 3D-printed head model, using the Euclidean distance of displacement of virtual objects. For clinical validation, 14 patients with brain tumors were included in the study. Preoperative MRI images were used to generate 3D models for AR contents. The 3D models were then transferred to the smartphone AR app. Tumor scalp localization was marked, and a surgical corridor was planned on the patient's head by viewing AR images on the smartphone screen. Standard neuronavigation was applied to evaluate the accuracy of the smartphone. Max-margin distance (MMD) and area overlap ratio (AOR) were measured to quantitatively validate the clinical accuracy of the smartphone AR technique. In model validation, the total mean Euclidean distance of virtual object displacement using the smartphone AR app was 4.7 ± 2.3mm. In clinical validation, the mean duration of AR app usage was 168.5 ± 73.9s. The total mean MMD was 6.7 ± 3.7mm, and total mean AOR was 79%. The smartphone AR app provides a new way of experience to observe intracranial anatomy in situ, and it makes surgical planning more intuitive and efficient. Localization accuracy is satisfactory with lesions larger than 15mm.

Patient-specific simulation of stent-graft deployment in type B aortic dissection: model development and validation

Thoracic endovascular aortic repair (TEVAR) has been accepted as the mainstream treatment for type B aortic dissection, but post-TEVAR biomechanical-related complications are still a major drawback. Unfortunately, the stent-graft (SG) configuration after implantation and biomechanical interactions between the SG and local aorta are usually unknown prior to a TEVAR procedure. The ability to obtain such information via personalised computational simulation would greatly assist clinicians in pre-surgical planning. In this study, a virtual SG deployment simulation framework was developed for the treatment for a complicated aortic dissection case. It incorporates patient-specific anatomical information based on pre-TEVAR CT angiographic images, details of the SG design and the mechanical properties of the stent wire, graft and dissected aorta. Hyperelastic material parameters for the aortic wall were determined based on uniaxial tensile testing performed on aortic tissue samples taken from type B aortic dissection patients. Pre-stress conditions of the aortic wall and the action of blood pressure were also accounted for. The simulated post-TEVAR configuration was compared with follow-up CT scans, demonstrating good agreement with mean deviations of 5.8% in local open area and 4.6 mm in stent strut position. Deployment of the SG increased the maximum principal stress by 24.30 kPa in the narrowed true lumen but reduced the stress by 31.38 kPa in the entry tear region where there was an aneurysmal expansion. Comparisons of simulation results with different levels of model complexity suggested that pre-stress of the aortic wall and blood pressure inside the SG should be included in order to accurately predict the deformation of the deployed SG.

Computed tomography in tetralogy of Fallot: pre- and postoperative imaging evaluation.

Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart disease (CHD) and the most frequent complex CHD encountered in adulthood. Although children with TOF share four characteristic features (subaortic ventricular septal defect, overriding aorta, right ventricular hypertrophy, pulmonary stenosis), the clinical spectrum and course are in fact greatly heterogeneous. Echocardiography remains the mainstay for diagnosis, presurgical planning and postoperative follow-up. However, with continued technological advances, CT now plays an increasing role in TOF evaluation and management, helping to minimize routine invasive catheter angiography. Preoperatively, CT is uniquely suited to assess associated pulmonary arterial, aortic and coronary anomalies as well as extra-cardiovascular structures and is particularly helpful for delineating complex anatomy in the TOF subtypes of absent pulmonary valve and pulmonary atresia with major aortopulmonary collaterals. Postoperatively, CT is useful for identifying surgical complications and for long-term monitoring including volumetry quantification, especially in children for whom MRI is contraindicated or limited by implanted devices such as pacemakers and stents. In this article, we review key clinical features and considerations in the pre- and postoperative TOF patient and the burgeoning role of CT for facilitating accurate diagnosis and personalized intervention.

Orthodontists' criteria for prescribing cone-beam computed tomography-a multi-country survey.

This study aimed to describe and compare CBCT imaging prescription in clinical practice among orthodontists from five countries in Europe and America. Additionally, it investigated factors associated with the prescribing and the use of guidelines for CBCT imaging. A cross-sectional survey was carried out using an online questionnaire sent to all registered orthodontists in Belgium, Brazil, Canada, Romania, and the United States of America (USA). The data were analyzed by descriptive statistics, bivariate tests, and Poisson regression. The final sample consisted of 1284 participants. CBCT was prescribed by 84.4% of the participants for selected cases (84.9%), mainly for impacted teeth (92.4%), presurgical planning (54.1%), and root resorption (51.9%). High cost was most frequently the limiting factor for CBCT prescription (55.4%). Only 45.2% of those who were using CBCT imaging reported adhering to guidelines. CBCT imaging prescription was associated with the orthodontists' countries (p < .009, except for Belgium, p = .068), while the use of guidelines was associated with the respondents' country and additional training on CBCT imaging (p < .001). Orthodontists refer patients for CBCT for selected indications (impacted teeth, root resorption, presurgical planning, dentofacial deformities, as suggested by the international guidelines, and also for upper airway and temporomandibular joint evaluation). Many do not adhere to specific guidelines. There are substantial variations between the countries about the orthodontists' referral for CBCT and guideline usage, irrespective of gender. CBCT prescription may be limited by financial barriers, adhering to specific guidelines and prior CBCT training. CBCT prescription among orthodontists must be based on prescription criteria and current guidelines. It is advised to improve CBCT education and training to enhance CBCT selection, referral, analysis, and interpretation in orthodontic practice.

The role of CT and MRI scans in maxillary sinus augmentation surgery

Diagnostic imaging has a primary role in presurgical planning. Computerized tomography has become a standard for assessing the feasibility of implant surgery. Three- dimensional diagnostic assessments have a decisive value in presurgical treatment planning, especially in situations in which the alveolar process has pronounced resorption, and therefore insufficient bone volume for placing endosseous implants. These situations, which once limited the placement of implants in the posterior maxilla, can now be overcome via maxillary sinus augmentation procedures. In these cases, diagnostic imaging, in particular using CT scans, plays a vital role in providing reliable and necessary information. MR imaging reveals to be ideal imaging in diagnosing maxillary sinus augmentation.

In Vivo Super-Resolution Track-Density Imaging for Thalamic Nuclei Identification.

The development of novel techniques for the in vivo, non-invasive visualization and identification of thalamic nuclei has represented a major challenge for human neuroimaging research in the last decades. Thalamic nuclei have important implications in various key aspects of brain physiology and many of them show selective alterations in various neurologic and psychiatric disorders. In addition, both surgical stimulation and ablation of specific thalamic nuclei have been proven to be useful for the treatment of different neuropsychiatric diseases. The present work aimed at describing a novel protocol for histologically guided delineation of thalamic nuclei based on short-tracks track-density imaging (stTDI), which is an advanced imaging technique exploiting high angular resolution diffusion tractography to obtain super-resolved white matter maps. We demonstrated that this approach can identify up to 13 distinct thalamic nuclei bilaterally with very high inter-subject (ICC: 0.996, 95% CI: 0.993-0.998) and inter-rater (ICC:0.981; 95% CI:0.963-0.989) reliability, and that both subject-based and group-level thalamic parcellation show a fair share of similarity to a recent standard-space histological thalamic atlas. Finally, we showed that stTDI-derived thalamic maps can be successfully employed to study structural and functional connectivity of the thalamus and may have potential implications both for basic and translational research, as well as for presurgical planning purposes.

Improving Patient Education of Facial Fractures Using 3-Dimensional Computed Tomography.

Advances in 3-dimensional modeling have revolutionized presurgical planning for maxillofacial reconstruction, yet little is known about how this technology may affect patient education. This study was designed to evaluate the efficacy of 2-dimensional computed tomography versus 3-dimensional computed tomography for patient education in maxillofacial reconstruction. Crossover study. General otolaryngology outpatients from a tertiary referral center were recruited. A single computed tomography data set of a zygomaticomaxillary complex fracture was used to generate 2 educational video tutorials: one in a 2-dimensional format and one in a 3-dimensional format. The tutorials were embedded into the QualtricsXM platform. Participants were randomly assigned into 2 groups. Group 1 viewed the 2-dimensional tutorial, took a self-assessment survey, took an information recall survey, viewed the 3-dimensional tutorial, and finally took a tutorial comparison survey. Group 2 followed the same sequence but viewed the 3-dimensional tutorial followed by the 2-dimensional tutorial. Group 2 participants (viewing the 3-dimensional tutorial first) scored better on the self-assessment survey than their counterparts in group 1 did (P = .023). Group 2 also scored better on the recall survey (P = .042). Of all participants, 61% preferred the 3-dimensional tutorial, and 31% preferred the use of both tutorials together in the comparison survey. Three-dimensional patient educational tutorial regarding a zygomaticomaxillary complex fracture resulted in better knowledge retention and was preferred over the 2-dimensional format.

Comparison of compressional and elastic wave simulations for patient-specific planning prior to transcranial photoacoustic-guided neurosurgery.

.Significance: Simulations have the potential to be a powerful tool when planning the placement of photoacoustic imaging system components for surgical guidance. While elastic simulations (which include both compressional and shear waves) are expected to more accurately represent the physical transcranial acoustic wave propagation process, these simulations are more time-consuming and memory-intensive than the compressional-wave-only simulations that our group previously used to identify optimal acoustic windows for transcranial photoacoustic imaging.Aim: We present qualitative and quantitative comparisons of compressional and elastic wave simulations to determine which option is more suitable for preoperative surgical planning.Approach: Compressional and elastic photoacoustic k-Wave simulations were performed based on a computed tomography volume of a human cadaver head. Photoacoustic sources were placed in the locations of the internal carotid arteries and likely positions of neurosurgical instrument tips. Transducers received signals from three previously identified optimal acoustic windows (i.e., the ocular, nasal, and temporal regions). Target detectability, image-based target size estimates, and target-to-instrument distances were measured using the generalized contrast-to-noise ratio (gCNR), resolution, and relative source distances, respectively, for each simulation method.Results: The gCNR was equivalent between compressional and elastic simulations. The areas of the contours of point spread functions utilized to measure resolution differed by 0.33 to . Target-to-instrument distance measurements were within 1.24 mm of the true distances.Conclusions: These results indicate that it is likely sufficient to utilize the less time-consuming, less memory-intensive compressional wave simulations for presurgical planning.

SPECTRUM OF MAGNETIC RESONANCE IMAGING FINDINGS IN RHINO-ORBITO-CEREBRAL MUCORMYCOSIS PATIENTS DURING SECOND WAVE OF COVID-19 INFECTION IN A TERTIARY CARE HOSPITAL – A PROSPECTIVE STUDY.

Introduction- Mucormycosis is a lethal intrusive opportunistic fungal infection with increased morbidity and mortality. Its most common form is Rhino-Orbital-Cerebral Mucormycosis (ROCM). It has been described more in immunosuppressed people and currently in patients with recent history of/ concomitant Covid-19 infection. Magnetic Resonance Imaging (MRI) has been used to delineate extent of infection and spread and preoperative planning. MRI shows varied T1 and T2 signal intensity lesions with nonenhancement in necrosed tissues and extension of infection into adjacent structures. This prospective study aimed at delineating the spectrum of MRI findings in ROCM patients. Methods and results- A prospective study of 31 patients with ROCM was done in Department of Radiology, Superspeciality hospital, Gajra Raja Medical College, Gwalior in May and June 2021 during second wave of COVID-19 pandemic. We found that 64.5% patients in study group had previously / recently diagnosed diabetes mellitus and 77.4% cases had recently treated or concomitant COVID-19 infection. All the patients had sinonasal involvement at the time of imaging. The other areas of involvement were orbit and its contents, some of adjacent soft tissues, cavernous sinus and cerebral parenchyma, hard palate and cavernous ICA in order of frequency. Conclusion- ROCM is a grave infection which readily causes perivascular, perineural and soft tissue infiltration within a short span of time, hence most of the patients in this study had extension beyond the sinuses at the time of imaging. MRI is an essential tool for early identification of extrasinus extension of disease, detection of intracranial and vascular complications and presurgical planning.

Prevalence of bifid and trifid mandibular canals with unusual patterns of nerve branching using cone beam computed tomography.

Lack of knowledge concerning the inferior alveolar canal anatomical variations had proven to increase the incidence of surgical complications, so the study aimed to assess the configuration and prevalence of bifid and trifid mandibular canals using cone beam CT in Egyptian subpopulation. Cone beam CT scans of 278 patients (530 hemi-mandibles) were included in the study, in which bifid and trifid mandibular canals or any other branching patterns were recorded and evaluated. Bifid canals were categorized following Naitoh classification, and the diameter of the main mandibular and accessory canals was measured. Bifid canals were detected in 181 canals (34%) while trifid canals in 46 canals (8.7%). Upon classifying the bifid canals, 78 canals showed forward type, 40 retromolar type, 33 dental type, and 7 canals showed buccolingual type. Two special bifid canals subtypes were reported in 23 canals and nine distinct patterns of trifid canals were reported in our study. In addition, unusual patterns of canal branching were reported in 5 cases. The mean diameter of the accessory canals was 1.18 ± .54mm and the main canal was 3.98 ± 1.31mm. This study reported a high prevalence (54%) of canal branching, which reinforces the importance of cone beam CT in pre-surgical planning.