Critical Anatomical Areas Research Articles

A 3D-Planned Inward Fragmentation Technique for the Removal of Impacted Mandibular Third Molars: A Case Series.

Background/Objectives: The extraction of impacted mandibular third molars (M3Ms) carries significant risks, especially regarding the inferior alveolar nerve (IAN). This study aimed to evaluate the effectiveness of a 3D-planned inward fragmentation technique (3Dp-IFT) to improve surgical outcomes, reduce complications, and preserve bone structure in cases involving complex M3M impactions. Methods: Twenty-three patients aged between 18 and 36 years requiring M3M removal were included. Preoperative planning involved the use of cone-beam computed tomography (CBCT) for precise localization of the furcation area, followed by the creation of a 3D navigation template using PlastyCAD software version 1.7. The surgical procedure was performed under local anesthesia, with meticulous endoscopic assistance to ensure accurate access and minimize trauma. Postoperative outcomes, such as bone loss, pain, swelling, and mouth opening range, were carefully measured. The data were systematically organized and analyzed descriptively using Microsoft Excel. Results: No disturbances to the IAN or lingual nerve were observed. The mean buccal bone loss was 2.2 mm, with a standard deviation of 1.2 mm. Postoperative pain and swelling were generally low, with significant reductions within the first week. The use of the 3D navigation template significantly improved surgical access, enhancing safety and minimizing complications. Conclusions: The 3Dp-IFT technique represents a significant advancement in the minimally invasive removal of M3M by allowing precise access to critical anatomical areas while minimizing bone loss and postoperative complications. This approach is particularly beneficial for complex cases involving M3M near the IAN, thereby improving surgical safety and patient outcomes.

RobMedNAS: searching robust neural network architectures for medical image synthesis

Investigating U-Net model robustness in medical image synthesis against adversarial perturbations, this study introduces RobMedNAS, a neural architecture search strategy for identifying resilient U-Net configurations. Through retrospective analysis of synthesized CT from MRI data, employing Dice coefficient and mean absolute error metrics across critical anatomical areas, the study evaluates traditional U-Net models and RobMedNAS-optimized models under adversarial attacks. Findings demonstrate RobMedNAS’s efficacy in enhancing U-Net resilience without compromising on accuracy, proposing a novel pathway for robust medical image processing.

Study on Lattice Radiotherapy Treatments (LRT) for Head and Neck Bulky Tumors

Lattice radiotherapy (LRT) exploits various effects of radiation, such as the bystander effect and the abscopal effect, and consists on the administration of high dose fraction in small areas with large tumor masses, helping to solve the problem of treating bulky disease, especially if it is located in a critical anatomical area. The optimization of LRT treatment plans is challenging due to the difficulty to generate spots of high dose within the tumor with consequent high gradient. This study compares the plan dosimetry and delivery time of two delivery techniques VMAT and CyberKnife for LRT treatments of bulky head and neck lesions. Six patients with giant head and neck tumors who received LRT at our institution were included in this study. Target and OARs were contoured following international guidelines; to allow easy identification of the desired high gradient zones, an artificial geometrical lattice structure with spherical vertices was arranged inside the target volume (GTV), and the vertices of the lattice representing the high dose boost volumes (GTVboost) were delineated. The GTVboost and GTV were prescribed to receive 12 Gy and 3 Gy, respectively in a single fraction. Separate VMAT and CyberKnife LRT plans were optimized for each patient with lattice vertex of 0.5 diameter and center-to-center distances of 1.5 cm (LRT1.5) and 3 cm (LRT3). The dose heterogeneity was measured as the peak-to-valley dose ratio (PVDR), with the traditional definition being replaced by the D10/D90 ratio, where D10 and D90 represent the doses covering 10% and 90% of the GTV, respectively. For each plan generated, the treatment delivery time, the monitor units (MU), and the PVDR were assessed. Pre-treatment plan verifications were performed with ArcCheck array and Gafchromics film for VMAT and CyberKnife, respectively, using gamma analysis criteria of 3%-3mm. The mean PVDR obtained for VMAT LRT plans were 2.0 and 2.6 for LRT1.5 and LRT3, respectively, and 3.2 and 4.7, respectively for CyberKnife LRT plans. For each pre-treatment plan dose verification, the gamma passing rate (GPR) was higher than 95.0 %; CyberKnife delivery time and MU were more than 10 times higher than that of VMAT, nevertheless, VMAT had a lower PVDR. The detailed results are shown in the table below. CyberKnife LRT has a strong ability to place the peak dose within the target, generating a higher peak-to-valley dose ratio, however its use is partially invalidated by the long beam delivery times and the resulting high MU number; the use of the VMAT LRT technique allows clinically adequate dosimetry with acceptable delivery times.

Effective reduction of scatter radiation for operator and assistant during coronary procedures with a suspended radiation protection system in a per-procedure live-dosimetry analysis

Abstract Background Interventional cardiologists (IC) are exposed to the highest doses of radiation compared to all other medical specialties. Although head and eyes are exposed to a significant dose of scatter radiation (SCR), precise per-procedure data is sparse. Recently, the EU guidelines for maximum eye lens SCR doses have been reduced from 150 mSv to 20 mSv per year. A ceiling suspended operator radiation protection system has shown additional benefits for SCR protection in radiologic interventional procedures. Purpose To study the impact of the ZG system on IC and sterile assistant (SA) SCR exposure when used in addition to the current standard of X-ray protection (SXP) in unselected all-comers cardiologic procedures. Methods IC and SA were equipped with Unfors RaySafe i3 live-dosimeters at prespecified locations. 181 consecutive cardiac procedures were recorded, in which either both IC and SA were using SXP (lead apron, thyroid shield) or the IC was using the ZG system and the SA was wearing SXP. In all procedures a suspended lead shield, patient lead cover and an adjustable lead side-shield were present. Diagnostic angiographies (DA) and interventions (PCI) were grouped separately. Within both groups, the IC's and SA's SCR doses were compared. Results SCR doses were recorded in 100 DA and 81 PCI procedures. Compared to SXP, the use of the ZG device reduced the average SCR doses per procedure of the IC recorded at the left lateral head from 5.18±1.11 μSv to 0.60±0.07 μSv in DA (−88%; n=49/49, p<0.0001) and from 19.64±3.36 μSv to 1.05±0.28 μSv for PCI (−95%; n=54/23, p=0.0006). The IC's average frontal dose at eye level was reduced from 1.38±0.33 μSv to 0.36±0.04 μSv in DA (−74%; n=50/50, p=0.0033) and from 3.33±0.53 μSv to 0.88±0.20 μSv in PCI (−74%; n=55/25, p=0.0031). Consistently, the dose recorded immediately under the IC's left shoulder were reduced from 34.14±7.79 μSv to 1.59±0.32 μSv in DA (−95%; n=39/40, p=0.0001) and from 71.77±10.77 μSv to 3.95±0.83 μSv in PCI (−94%; n=44/23, p=0.0001). Furthermore, when the IC used the ZG system, the average SCR dose recorded at the SA's head was reduced from 4.32±0.98 μSv to 2.11±0.28 μSv in DA (−51%, n=45/49, p=0.027) and from 18.55±2.69 μSv to 6.93±1.93 μSv in PCI (−63%, n=54/24, p=0.0078). With the exception of the IC frontal dose, all SCR dose effects remained significant after correction for total radiation time (μSv/s) and dose-area product (μSv/Gy·cm2). Procedure duration, contrast use and patient radiation dose were not affected by ZG use. Conclusions In a representative all-comers cohort of cardiac procedures, the ZG X-ray protection system demonstrated an impressive potential for SCR reduction in critical anatomical areas - even in a state-of-the-art cath-lab inventory with multiple SCR reduction measures already in place. Remarkably, the protective effect also included the sterile assistant at the table wearing SXP. Funding Acknowledgement Type of funding sources: None.

Lattice or Oxygen-Guided Radiotherapy: What If They Converge? Possible Future Directions in the Era of Immunotherapy

Simple SummaryOxygen-guided radiotherapy is a new modality for cancer irradiation. Spatially Fractionated Radiation Therapy allows the treatment of hypoxic tumor areas with high radiation doses. Radiotherapy enhances immunotherapy effectiveness. Abscopal and bystander effects are important radiobiological issues. The aim of this paper was to analyze the recent development of a particular kind of radiation therapy that is based on high-dose delivery in small areas within large tumor masses. We performed a narrative review of the radiobiological rationale behind a potential benefit by using these techniques combined with immunotherapy and employing personalized target definition according to hypoxic areas.Palliative radiotherapy has a great role in the treatment of large tumor masses. However, treating a bulky disease could be difficult, especially in critical anatomical areas. In daily clinical practice, short course hypofractionated radiotherapy is delivered in order to control the symptomatic disease. Radiation fields generally encompass the entire tumor mass, which is homogeneously irradiated. Recent technological advances enable delivering a higher radiation dose in small areas within a large mass. This goal, previously achieved thanks to the GRID approach, is now achievable using the newest concept of LATTICE radiotherapy (LT-RT). This kind of treatment allows exploiting various radiation effects, such as bystander and abscopal effects. These events may be enhanced by the concomitant use of immunotherapy, with the latter being ever more successfully delivered in cancer patients. Moreover, a critical issue in the treatment of large masses is the inhomogeneous intratumoral distribution of well-oxygenated and hypo-oxygenated areas. It is well known that hypoxic areas are more resistant to the killing effect of radiation, hence the need to target them with higher aggressive doses. This concept introduces the “oxygen-guided radiation therapy” (OGRT), which means looking for suitable hypoxic markers to implement in PET/CT and Magnetic Resonance Imaging. Future treatment strategies are likely to involve combinations of LT-RT, OGRT, and immunotherapy. In this paper, we review the radiobiological rationale behind a potential benefit of LT-RT and OGRT, and we summarize the results reported in the few clinical trials published so far regarding these issues. Lastly, we suggest what future perspectives may emerge by combining immunotherapy with LT-RT/OGRT.

Ultrasound guided fine needle aspiration cytology of intra-abdominal masses in a tertiary center of Bihar, India

Ultrasonography (USG)-guided fine needle aspiration cytology (FNAC) has become an indispensable component of diagnosis of abdominal masses especially the pancreato-biliary system. It allows the real time visualization of the needle tip as it passes through the tissue planes into the target area. Under USG guidance, needle can access smaller lesions and also lesions in critical anatomical areas. The study involved 50 cases with clinically or ultrasonographically diagnosed of abdominal masses conducted in the department of pathology, Patna Medical College, Patna, India. Among total 50 patients in the study, 33 (66%) were female and 17 (34%) were male. The age ranged from 4 to 75 years. The most common site of FNAC was Gall bladder, being 38/50 (76%). Among the total 50 cases, 28 (56%) were malignant, 17 (34%) were benign and 5 (10%) were inconclusive. The most common age group was 51 to 60 years constituting 15/50 (30%) cases. Out of these 15 cases, 13 were malignant and 2 were benign. The most common malignancy seen, was carcinoma of Gall bladder, predominantly in females living in Gangetic belt (people living near the river Ganga) of Bihar, were the Arsenic content of soil is said to be very high. USG-guided FNAC procedure involves the presence of both a pathologist and a radiologist, thereby facilitating the exact mass to be hit by the needle for FNAC and appropriate handling of aspirated material for routine and ancillary tests. Real time USG is a simple, cost-effective imaging modality, has an advantage over computed tomography (CT) in guiding non-axial needle trajectories and allowing the procedure to be accomplished more quickly than CT.

Neurotoxicidad cognitiva inducida por la radioterapia cerebral en adultos

Cognitive toxicity induced by cranial radiation is one of the most important limitations of radiation therapy and has a significant impact on brain tumor survivors' quality of life. This review comprehends an up to date of recent studies including complete neuropsychological battery and/or advanced neuroimaging techniques. These studies identified critical anatomical and/or functional brain areas related to radiation-induced brain injury, thus improving clinical and radiological diagnosis. Pathophysiological mechanisms underlying cognitive toxicity are complex and involve different cell lines and molecules. Although there is no currently therapeutic strategy that has a demonstrated efficacy, several studies including sparing of hippocampus or the use of memantine are quite promising. A better knowledge of the characteristics of cognitive toxicity induced by cranial radiation, will help us to identify patients who will benefit from treatment and also to examine new therapeutic targets in order to improve patients' quality of life.

Three-dimensional conformal radiation therapy for the osteoarthritis of knee joint: the radiobiological background, dose distribution analysis

Osteoarthritis (OA) is the most frequent rheumatological pathology of the joints. Standard medical treatment does not always allow to stop the pain syndrome. The alternative method of pain treatment causes by OA is orthovoltage X-ray therapy (OVRT). It was used from 1970. The maximum dose by OVRT lies on the skin surface. Based on the modern methods of diagnosis, choosing the appropriate radiation energy, it is possible to reduce the amount of irradiation of the knee joint.The purpose. Is to present the technique of radiation planning in patients with gonarthritis and compare it with OVRT by dosimetry criteria.Materials and methods. Comparison of dose distribution plans of the orthovoltage beam was carried out according to the two-dimensional axial plan in the area of the isocenter for the energy of 200 kV from two tangential fields and a megavoltage energy beam of 6 MeV for a three-dimensional conformal radiation therapy using 3-and 6-fields isocentric irradiation techniques. To describe amounts of radiation were applied to the CTV (clinical target volume) and PTV (planning target volume). To estimate the volume distribution of the dose, bones forming the knee joint were contoured separately. The indent on the PTV was 3 mm.Results. The application of the 6-fields technique allows achieving 95% dose distribution at 93% of the volume, and 90% of the planned dose of 45 SGR covers 97% of the PTV. The average dose on the skin and the neurovascular bundle are of 150 and 240 cGy, respectively. The average radiation dose per course in critical anatomical areas is 280 cGy and 150 cGy. It can be considered that the target coverage for the compared methods is similar as for OVRT, and for 3D conformal radiation therapy plans for dose distribution of the orthogonal beam in the axial plane in comparison with dose distributions for conformal radiation techniques.Conclusion. The technique of three-dimensional conformal radiation therapy of the knee joint in OA with progressive pain syndrome can potentially lead to an increase in the analgesic effect due to greater coverage with a dose of bone elements of the joint, which are a potential source of pain. Three-dimensional conformal radiotherapy megavoltage beam allows reducing the radiation load on the skin in 2.5 times, which can reduce the frequency of delayed adverse effects.

Sinonasal Neoplasia - Clinicopathological Profile And Importance of Computed Tomography.

Nasal cavity and Paranasal sinus malignancies are very rare, in which maxillary sinus is the commonest, followed by ethmoid, frontal and sphenoid sinus. Computed Tomography (CT) & Magnetic Resonance Imaging (MRI) play a key role in diagnosis, staging and management of paranasal sinuses and nasal pathologies. Multiplanar imaging in CT helps better imaging of critical anatomical areas. Aim of our study was to study the incidence, clinical features, CT features and its importance in the management of sinonasal neoplasms. This prospective study was carried out in a tertiary care hospital of MP, India. Consecutive 40 histologically proven cases of sinonasal neoplasia who visited the Department of Otorhinolaryngology and Radiotherapy are included in our study. Demography and clinical features were recorded. Cases of nasal and paranasal sinus masses diagnosed on CT attending ENT and Radiotherapy OPD or admitted in the Radiotherapy ward forms the material of this study. This included patients of both sexes and all ages. Histopathological examination was asked to confirm the diagnosis made on CT. There were total 40 cases of sinonasal neoplasia among which 24 were benign. Almost all the benign cases were seen in the age group <40 y with mean age of 20 y and most of the malignant cases were seen in the age group above 40 y with mean age of 55 y. In our study we found male preponderance with male female ratio of 4:1 in both benign and malignant conditions. The commonest presenting symptoms of the patients with sinonasal masses in our study was nasal obstruction (75%) and nasal discharge (67.5%) followed by nasal mass (65%), epistaxis (62.5%) and headache (60%). Angiofibroma and papilloma were the commonest benign lesions. Commonest malignant lesion was squamous cell carcinoma. Of the malignant Sinonasal tumours studied in our series, maxillary sinus was involved in 13, ethmoid sinuses and nasal cavity in 10 cases each, and frontal sinuses in 2 cases. Contrast enhanced computed tomography with multiplanar reconstruction is an excellent modality for imaging sinonasal masses. CT can define the character of the sinonasal mass, thus differentiating benign from malignant. CT helps better imaging of critical anatomical areas and helpful in planning treatment procedures such as surgery and radiotherapy.

Treatment of anterior crossbite and its influence on gingival recession

Several etiological factors for gingival recession have been discussed in the literature, and the vestibular region of the mandibular incisors is a critical anatomical area for the emergence of this condition. Anterior crossbite is an important factor, because the trauma from occlusion between the incisors generates an imbalance in the distribution of forces, causing changes in the periodontium and making the area more susceptible to mechanical trauma during brushing and to plaque formation. In view of these aspects, the objective of this paper was to demonstrate the influence of early treatment of anterior crossbite on the gingival margin level and risk of gingival recession in the region of the incisors. A case of anterior crossbite treated during the mixed dentition phase was used as an example. After orthodontic therapy with the use of a removable appliance with a finger spring, we noticed improvement in periodontal health and esthetics as the tooth was reattached at its base bone.

Transorbital stab injury with retained knife: a narrow escape.

Transorbital penetrating injuries are unusual but may cause severe brain damage if cranium is entered. These kinds of injuries are dangerous as the walls of orbit are very thin, hence easily broken by the otherwise innocent objects. Because of the very critical anatomical area involved, these injuries pose a serious challenge to the physicians who first receive them as well as the treating team. These may present as trivial trauma or may be occult and are often associated with serious complications and delayed sequel. Prompt evaluation by utilizing best diagnostic modality available and timely interference to remove them are the key aspects to avoid damage to vital organs surrounding the injury and to minimize the late complications. We report a case of transorbital assault with a 13 centimeter long knife which got broken from the handle and the blade was retained. The interesting aspect is that there was no neurological deficit on presentation or after removal.

Diffuse Malignant Peritoneal Mesothelioma: Failure Analysis Following Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy (HIPEC)

Improved survival has been reported for diffuse malignant peritoneal mesothelioma (DMPM) treated by cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). The issue of treatment failure has never been extensively addressed. The present study assessed the failure pattern, management, and outcome of progressive DMPM following comprehensive treatment. Clinical data on 70 patients with DMPM undergoing cytoreduction and HIPEC were prospectively collected; after a median follow-up of 43 months, disease progression occurred in 38 patients. Progressive disease distribution in 13 abdominopelvic regions was analyzed. In 28 patients undergoing adequate cytoreduction (residual tumor < or =2.5 mm), clinicopathological factors correlating to disease progression in each region were investigated. Median time to progression was 9 months [95% confidence interval (CI) 1.6-35.9]. Median survival from progression was 8 months (95% CI 4-16.2). The failure pattern was categorized as peritoneal progression (n = 31), liver metastases (n = 1), abdominal lymph-node involvement (n = 2), pleural seeding (n = 4). Small bowel was the single site most commonly involved (n = 27). Residual tumor < or =2.5 mm (versus no visible) was the only independent risk factor for disease progression in epigastric region (P = 0.047), upper ileum (P = 0.029), upper jejunum (P = 0.034), and lower jejunum (P = 0.002). Progressive disease was treated with second HIPEC in 3 patients, debulking in 4, systemic chemotherapy in 16, and supportive care in 15. At multivariate analysis, time to progression <9 months (P = 0.009), poor performance status (P = 0.005), and supportive care (P = 0.003) correlated to reduced survival from progression. We conclude that minimal residual disease, compared with macroscopically complete cytoreduction, correlated to failure in critical anatomical areas, suggesting the need for maximal cytoreductive surgical efforts. In selected patients, aggressive management of progressive disease seems worthwhile.

Studying the human brain anatomical network via diffusion-weighted MRI and Graph Theory

Our goal is to study the human brain anatomical network. For this, the anatomical connection probabilities (ACP) between 90 cortical and subcortical brain gray matter areas are estimated from diffusion-weighted Magnetic Resonance Imaging (DW-MRI) techniques. The ACP between any two areas gives the probability that those areas are connected at least by a single nervous fiber. Then, the brain is modeled as a non-directed weighted graph with continuous arc weights given by the ACP matrix. Based on this approach, complex networks properties such as small-world attributes, efficiency, degree distribution, vulnerability, betweenness centrality and motifs composition are studied. The analysis was carried out for 20 right-handed healthy subjects (mean age: 31.10, S.D.: 7.43). According to the results, all networks have small-world and broad-scale characteristics. Additionally, human brain anatomical networks present bigger local efficiency and smaller global efficiency than the corresponding random networks. In a vulnerability and betweenness centrality analysis, the most indispensable and critical anatomical areas were identified: putamens, precuneus, insulas, superior parietals and superior frontals. Interestingly, some areas have a negative vulnerability (e.g. superior temporal poles, pallidums, supramarginals and hechls), which suggest that even at the cost of losing in global anatomical efficiency, these structures were maintained through the evolutionary processes due to their important functions. Finally, symmetrical characteristic building blocks (motifs) of size 3 and 4 were calculated, obtaining that motifs of size 4 are the expanded version of motif of size 3. These results are in agreement with previous anatomical studies in the cat and macaque cerebral cortex.

Human thoracic anatomy based on computed tomography for development of a totally implantable left ventricular assist system.

Human thoracic anatomy was studied using computed tomography (CT) for the development of a totally implantable electrohydraulic left ventricular system [Nimbus, Inc., and The Cleveland Clinic Foundation (CCF)]. To obtain statistical dimensional information for the chest wall, apex of the heart, and aorta, routine calibrated CT scans of 18 men and 17 women were analyzed. A special radiopaque vest was worn by the patient just prior to the scanning and X-ray procedures, so that each transverse scan could be assigned to a specific chest level after combination with a standard vertical referencing system set on the patient's radiogram. A polar coordinate system and direct measurement of transverse distances from the vertical column to points on the chest wall were employed to define collectively the shape and size of the intrathoracic surface of the chest wall. Locations of the aorta and apex were described by measuring their normalized distances from the midline and vertical column to the intrathoracic surface of the lateral and anterior chest wall. The radius of curvature of the intrathoracic wall lateral to the left ventricle was determined to be approximately 10.4 cm for the average adult male chest. The present CCF intrathoracic pump with this curvature fits fairly well in both the average and individual thoraxes of these adult males. The location of the aorta, particularly of the descending aorta, was used to determine the optimal outlet design. The most critical anatomical area was the apex location. For adult males, an average distance of 2.8 cm from the apex to the internal chest wall was found. Because of this small dimension, careful design of the inflow port is being performed to avoid anatomical mismatch.

The Pivotal Role of Grammar in Correcting Writing Disabilities

Neurological research supports the hypotheses that (a) there is a critical anatomical area essential to the processing of grammatical information, and (b) the processing of grammatically organized information is distinct from the processing of information that is not grammatically organized. Research on the acquisition of language demonstrates that children can easily learn context-free grammatical structures, and that children universally generate nonoccurring utterances. On the basis of this research, a prototype for instructing writing-disabled students is developed.