Cranial Computed Tomography Scan Research Articles

Reversible intracranial contrast medium accumulation after embolization of unruptured cerebral aneurysms and its association with transient neurological deficits: A single center experience.

Use of iodine-containing contrast medium (CM) is obligatory for endovascular treatment (EVT) of cerebral aneurysms. After EVT, intracranial density increases (DIs) can be detected in cranial computed tomography (CT). Those DI can correspond to subarachnoid hemorrhage (SAH), infarction or reversible CM accumulation (RCMA). The latter can be mistaken for hemorrhage, especially if they are accompanied by neurological deficits. To analyze postinterventional DI after EVT of unruptured cerebral aneurysms and associated clinical symptoms and to identify risk factors for the occurrence of RCMA. For differentiation of DI, we compared CT scans following EVT and additionally 24 h ± 5 h later. Diagnosis of RCMA was based on marked regression of DI on follow-up scans. We analyzed continuous variables (age, duration of intervention and anesthesia, aneurysm diameter, amount of CM and renal function) and categorial variables (gender, aneurysm location, devices for EVT, antiplatelet therapy [APT] and associated neurological deficits) to identify risk factors for the occurrence of RCMA. We studied 58 patients (44 female, mean age 59.5 [range 39-81]) who underwent EVT for a total of 68 cerebral aneurysms in 62 therapy sessions over a 3-year period without periprocedural complications. Postinterventional DI occurred after 17 therapy sessions. All 17 DI turned out to be RCMA in the follow-up imaging. Two patients who had no DI on initial postinterventional CT showed new SAH on follow-up CT. Infarctions were not observed. Transient neurological deficits occurred in eight patients (12.9%) and were associated with RCMA (P = 0.010). Postinterventional RCMA was associated with the duration of EVT (P = 0.038) and with APT (acetylsalicylic acid [ASA] + clopidogrel: P =0.040; ASA alone: P =0.011). RCMA is common after EVT of unruptured cerebral aneurysms and often accompanied by transient neurological deficits. Long procedure duration and APT appear to predispose to the occurrence of RCMA.

Computed Tomographic Assessment of the Pattern of Head Injuries in a Developing Country: A Retrospective Review in a University Teaching Hospital in Nigeria

Abstract Background: Globally, head injury (HI) constitutes a major cause of morbidity and mortality. In many developing countries, there is inadequate access to diagnostic computed tomography computed tomography (CT) scan for assessment of suspected cases of HI. This study was aimed at assessing the pattern of HI presentations in a referral health facility in a developing country setting. Materials and Methods: Retrospective review of CT scans done for suspected cases of HI seen for 12 months in a Nigerian University teaching hospital. Chi-square and Fisher’s exact tests were used to identify factors associated with the severity of HI. Results: Seventy-nine cases of HI were seen. Most subjects were males (75, 94.9%) and within 21–30 years (31.6%). Majority of subjects (76.0%) had moderate-to-severe forms of HI. Road traffic accident (RTA) was the most common cause of HI (59, 74.7%). The most common pathology was hematoma (60, 75.9%) and was commonly in single locations (36, 60.0%). Skull fracture was the second-most common pathology (42, 53.2%) and was commonly in multiple locations. RTA, skull fracture, and multiple hematomas were associated with moderate-to-severe forms of HI. Conclusion: RTA was the most common cause of HI in the hospital. The incidence of HI was higher in males than females, who were largely in the most productive age group. The most common abnormalities were hematoma and skull fractures, and they were associated with severe forms of HI, thus, justifying the need for the availability and use of cranial CT scan in head trauma.

Intracranial physiological calcifications: A computed tomography study

AbstractBackground and aimIntracranial calcifications (ICs) occur when metals such as calcium or iron accumulate in blood vessels, glands or other structures related to the brain. They can be physiological or pathological. Currently, the most sensitive method for imaging IC is cranial computed tomography (CT). The aim of this retrospective study was to evaluate physiological ICs and the co-existence of them by CT.Patients and methods1,000 cranial CT scans of patients were retrospectively evaluated. Pineal calcification, choroid plexus calcification, habenular calcification, petroclinoid ligament calcification, basal ganglia calcification, falx cerebri and tentorium cerebelli calcification were evaluated and recorded.ResultsOf 1,000 patients, 65.7% had IC. The incidence of ICs in different sites were as follows: pineal calcification (37.7%), choroid plexus calcification (52.1%), habenular calcification (33.5%), petroclinoid calcification (21.8%), basal ganglia calcification (0.6%), falx cerebri calcification (6.2%) and tentorium cerebelli calcification (0.2%). The incidence and co-existence of calcifications were significantly higher in females than in males (P < 0.05). Pineal, choroid plexus, petroclinoid ligament calcifications were significantly higher in females than in males (P < 0.05). The incidence and co-existence of calcifications increased with age. Tentorium Cerebelli calcification did not differ significantly between age groups (P > 0.05).ConclusionsICs may be a common finding and encountered incidentally on CT scans which is gold standard to evaluate them. It is important to distinguish physiological calcifications from pathological ones, in the differentiation of pathological lesions with calcifications.

Fracture of the Petrous Carotid Canal

A 23-year-old male motorcyclist experienced blunt head trauma with loss of consciousness, headache and vomiting, epistaxis and right otorrhagia after a collision with a motor vehicle. Fractures involving the right parietal and temporal bones, as well as acute subdural and subarachnoid hemorrhage were identified on a cranial and facial CT scan. On independent evaluation of the imaging study, a subtle but distinct fracture line in the skull base involving the petrous carotid canal was identified. (Figure 1) The patient subsequently underwent CT angiography to evaluate for any injury to the internal carotid artery. In this examination, good opacification of the internal carotid arteries and their branches was noted, with no evident aneurysm, arteriovenous malformation or arteriovenous fistula formation.
 In patients with temporal bone fractures, the most commonly encountered complications are: tympano-ossicular injury causing conductive hearing loss, cochlear or vestibular injury causing sensorineural hearing loss or vertigo, facial nerve trauma causing facial paralysis, and fractures of the tegmen or posterior cranial fossa plate causing cerebrospinal fluid leaks.1 On the other hand, injury to the intratemporal portion of the internal carotid artery has been described as a rare complication and as such may be overlooked.1 However, its potentially devastating and life-threatening sequelae necessitates a purposeful and intentional evaluation for its presence. These sequelae include brain ischemia from arterial dissection or complete vascular occlusion, exsanguinating epistaxis or otorrhagia from carotid pseudoaneurysms, and the formation of carotid-cavernous fistulas.2 The incidence of involvement of the carotid canal in skull base fractures has been reported to be around 24%, with around 11% of this group developing internal carotid artery injuries.3 As such, the presence of fractures involving the petrous carotid canal is an indication for CT or MR angiography to further evaluate the internal carotid artery.4

Rectal dural metastasis masquerading as chronic subdural hematoma: illustrative case.

Intracranial dural metastasis causing subdural hematoma formation is a rare clinical entity associated with significant morbidity and mortality. A 61-year-old female patient known to have rectal signet ring cell carcinoma presented with cranial computed tomography scan findings of bilateral subdural hematoma. She underwent evacuation of the hematoma with dural biopsy, which showed tumor emboli consistent with colorectal origin. There was an early recurrence of the subdural collection, and an emergency subdural-peritoneal shunt insertion was done; however, there was no sustained clinical improvement. This work reports the first case of rectal dural metastasis presenting as chronic subdural hematoma and discusses the clinical course and current literature. The cases described in these studies are consistent with the clinical course of our patient; that is, evacuation of the subdural hematoma provided temporary clinical improvement and re-accumulation occurred within 3 days. The authors recommend maintaining a high index of suspicion in this select group of patients, including prompt discussion about treatment plans with the patient's family.

Pediatric Sinogenic Subdural Empyema: Case Report and Operative Technique

Intracranial complications of sinusitis in the pediatric age are rare but potentially life threatening. They usually occur with nonspecific symptoms such as headache, fever, nausea and vomiting rather than a classic neurological presentation, but they may evolve in few hours, leading to significant morbidity with permanent brain damage and sometimes to death. For this reason, early diagnosis and prompt treatment are essential. Our case demonstrates a sinogenic subdural empyema in an immunocompetent young boy who reached our Emergency Department due to a continuous right-sided headache, unresponsive to pain relievers. The clinical history and the diagnostic process are described: at first, laboratory exams, neurologic and otolaryngological assessment were performed, together with a cranial CT scan showing an inflammatory involvement of the right frontal, ethmoidal and maxillary sinuses. Intravenous antibiotic therapy was initiated. After a few hours the patient showed a sudden worsening of his clinical conditions: he was drowsy with left lower extremity hyposthenia and ipsilateral deep tendon reflexes absence. Considering the patient’s aggravated clinical presentation an emergent MRI with contrast enhancement was conducted, showing left midline shift, a widening of the liquor space on the right frontal and parietal convexity and noticeable meningeal enhancement after contrast injection. After a Neurosurgical and ENT evaluation the patient was taken to the operating room for a combined craniotomy and trans-nasal endoscopic drainage of the empyema. We present the surgical procedure with a pictorial step-by-step description. After the surgical procedure the patient’s condition gradually improved. He regained full neurological function, was accompanied by a rehabilitation team on recovering full force on the left extremities. At discharge the patient had no apparent neurological deficits. Subdural empyema is a rare but severe complication of pediatric sinusitis. Early diagnosis with combined medical and surgical therapies play a key role to reduce morbidity and mortality.

Teaching Neuro Images : Morgagni-Stewart-Morel

A 30-year-old woman presented with a 4-year history of slowly progressive memory loss, frontal headache, vertigo, depression, and seizures (normal EEG), and earlier history of endocrine disease (diabetes mellitus, obesity, hirsutism, and hypothyroidism). Sagittal cranial T1-weighted MRI, CT scan, and x-ray showed bilateral thickening of the inner table of the frontal bone (figure).1 Her paternal family history suggests X-linked disease. Her endocrine dysfunctions and neuropsychiatric symptoms are interpreted as components of Morgagni-Stewart-Morel syndrome and may correlate with the severity of the frontal hyperostosis and the cortical atrophy.2 Attention to this clinical–radiologic correlation may help neurologists make correct diagnoses.

Sudden and Unexpected Seizure during Emergency Cesarean Section in a Nonhypertensive Hypothyroid Primigravida

A 29-year-old primigravida parturient at term with a known case of hypothyroidism for the past 1 year was taken for emergency cesarean section in view of fetal distress. The patient's medical history showed a history of galactorrhea, for which magnetic resonance imaging of the brain and the routine blood investigations were normal. The parturient was posted for emergency cesarean section due to fetal distress. There was no significant comorbid illness or illicit drug intake. All the basic investigations including the thyroid-stimulating hormone were normal. Spinal anesthesia with 2.0 ml of 0.5% hyperbaric bupivacaine to achieve a level of T6 was performed. After the delivery of the fetus, there was a sudden seizure occurred, and the mother lost her consciousness. The hemodynamics remained stable. The patient was given oxygen, 2 mg of intravenous midazolam, and magnesium sulfate by the Pritchard regimen. The newborn's Apgar scores were normal. She had no recollection of the seizure attack after regaining consciousness and normal spontaneous respiration which occurred in a few minutes. Breastfeeding was recommended. To avoid another seizure episode, the Pritchard regimen was followed. The recovery period was uneventful. A cranial computed tomography scan of the brain was also performed, which revealed no abnormalities. Serum electrolytes were within the normal range when tested again. This case is being reported to raise awareness of seizures in nonhypertensive patients.

Cervical body composition on radiotherapy planning computed tomography scans predicts overall survival in glioblastoma patients

Background and purposeGlioblastoma (GBM) patients face a strongly unfavorable prognosis despite multimodal therapy regimens. However, individualized mortality prediction remains imprecise. Harnessing routine radiation planning cranial computed tomography (CT) scans, we assessed cervical body composition measures as novel biomarkers for overall survival (OS) in GBM patients. Materials and methodsWe performed threshold-based semi-automated quantification of muscle and subcutaneous fat cross-sectional area (CSA) at the levels of the first and second cervical vertebral body. First, we tested this method’s validity by correlating cervical measures to established abdominal body composition in an open-source whole-body CT cohort. We then identified consecutive patients undergoing radiation planning for recent GBM diagnosis at our institution from 2010 to 2020 and quantified cervical body composition on radiation planning CT scans. Finally, we performed univariable and multivariable time-to-event analyses, adjusting for age, sex, body mass index, comorbidities, performance status, extent of surgical resection, extent of tumor at diagnosis, and MGMT methylation. ResultsCervical body composition measurements were well-correlated with established abdominal markers (Spearman’s rho greater than 0.68 in all cases). Subsequently, we included 324 GBM patients in our study cohort (median age 63 years, 60.8% male). 293 (90.4%) patients died during follow-up. Median survival time was 13 months. Patients with below-average muscle CSA or above-average fat CSA demonstrated shorter survival. In multivariable analyses, continuous cervical muscle measurements remained independently associated with OS. ConclusionThis exploratory study establishes novel cervical body composition measures routinely available on cranial radiation planning CT scans and confirms their association with OS in patients diagnosed with GBM.

Comparison of structural occipital and iliac bone grafts for instrumented atlantoaxial fusions in pediatric patients: Radiologic research and clinical outcomes.

Structural autografts harvested from the iliac bone have been used in atlantoaxial fusion; they have been the gold standard for years. However, emerging occipital bone grafts have the advantage of avoiding donor-site morbidity and complications. Thus, we compared the clinical outcomes of structural autografts from the occipital bone or iliac crest and discussed the clinical significance of occipital bone grafts in pediatric patients. Pediatric patients who underwent posterior fusion using occipital bone grafts (OBG) or iliac bone grafts (IBG) between 2017 and 2021 were included in this study. Data on clinical outcomes, including operation time, estimated blood loss, length of hospitalization, complications, fusion rate, and fusion time, were collected and analyzed. Additionally, 300 pediatric patients who underwent cranial computed tomography scans were included in the bone thickness evaluation procedure. The central and edge thicknesses of the harvested areas were recorded and analyzed. Thirty-nine patients were included in this study. There were no significant differences in patient characteristics between the OBG and IBG groups. Patients in both groups achieved a 100% fusion rate; however, the fusion time in the OBG group was significantly longer than that in the IBG group. Estimated blood loss, operation time, and length of hospitalization were significantly lower in the OBG group than those in the IBG group. The surgery-related complication rate was lower, but not significantly, in the OBG group than that in the IBG group. For occipital bone thickness evaluation, a significant difference in the central part of the harvesting area was found between the young and old groups, with no significant sex differences. The use of OBG for atlantoaxial fusion is acceptable for pediatric patients with atlantoaxial dislocation, avoiding donor-site morbidity and complications.

The cognitive consequences of the COVID-19 infection and behavioral variant frontotemporal dementia: Is there a link?

IntroductionFrontotemporal dementia behavioral variant (bvFTD) is the most common subtype of frontotemporal dementia, characterized by early and often severely disabling alterations in personality and social conduct that carry a huge impact on the patient, family, and society.ObjectivesThe aim of the study was to correlate the clinical data collected from our patient with relevant literature and discuss the diagnosis of bvFTD in the context of the COVID-19 pandemic.MethodsCase report and a systematic review of the literature.ResultsThe middle-aged female patient we examined presented an array of psychiatric symptoms, including cognitive, behavioral, and personality changes that emerged in two months after a mild form of SARS-CoV-2 infection. Objectively, a cranial CT scan displayed frontal and anterior temporal lobe atrophy. The rapid and severe decline of the patient’s mental faculties throughout the last year, along with the circumstances in which the pathology developed, raised a question about the etiological factors that contributed to this early-onset dementia.ConclusionsAlthough diagnostic criteria are useful, frontotemporal dementia may be difficult to differentiate from other conditions because there are no disease-specific biomarkers. Correlations between the COVID-19 infection and the fulminant bvFTD symptoms remain unclear and require further investigations.Disclosure of InterestNone Declared

Differences in mastoid pneumatization between Asians and Caucasians

BackgroundAnatomical differences of the mastoid pneumatization in Asian and Caucasian patients must be considered when performing the retrosigmoid craniotomy since it may have implications to avoid specific complications such as cerebrospinal fluid infections or fistula. MethodsWe selected cranial CT scans of 120 Asian and 120 Caucasian patients, who were treated at the Mitsui Memorial Hospital (Japan) and at the Heidelberg University Hospital (Germany). Mastoid pneumatization was classified according to the relationship of the mastoid air cells (MAC) to the sigmoid sinus (Type I – III). The risk of mastoid air cell opening through craniotomy increases from Type I to III. Comparative analyses between gender and ethnicities were performed using the Chi2 Test and the independent T-Test and considered significant if p < 0.05. ResultIn Caucasians, Type III pneumatization was significantly overrepresented compared to Type II or I, compared to the Asian cohort (Type III:II:I in Caucasians = 60 %:26 %:14 %; in Asians = 28 %:43 %:29 %). Importantly, we found significant differences in pneumatization types between Caucasians and Asians in both gender subgroups (m: Type III 60 % vs 35 %; Type II 30 % vs 36.7 %; Type I 10 % vs 28.3 %, p = 0.008; f: Type III 60 % vs 23.3 %, Type II 21.7 % vs 48.3 %, Type III 18.3 % vs 28.3 %, p < 0.001; Chi2 Test). ConclusionCaucasian patients are more prone to the opening of the mastoid air cells than Asian patients when performing a retrosigmoid craniotomy due to differences in the degree of mastoid pneumatization. This may help to avoid complications such as postoperative infections or cerebrospinal-fluid fistula.

Intracranial aneurysms - a battle against time

Introduction: Intracranial aneurysms consist in abnormal dilatation of the cerebral arteries, most frequently asymptomatic, with symptoms appearing in the case of aneurysm rupture. From an imaging point of view, a cranial CT scan shows the subarachnoid haemorrhage caused by aneurysm rupture and the “gold standard” for aneurysm diagnosis is cerebral angiography.&#x0D; Case presentation: A 49 years-old female, Ukrainian refugee, presented with a unique comitial crisis and chronic headache. Following an MRI performed in Kiev, it was decided to perform a bilateral carotid and vertebral angiography in our clinic. Clinical and imagistic results showed a giant left middle cerebral artery aneurysm. Postoperative, the patient had a favourable neurological recovery, with no neurological deficits. Additionally, control angiography and CT scan highlight complete occlusion of the aneurysm and no complications.&#x0D; Conclusions: Cerebral aneurysms represent a high-risk vascular condition that needs a CT scan and angiography to be precisely diagnosed, surgical clipping should be performed as soon as possible.

Surface regularity: A new factor for predicting the expansion of intracerebral hemorrhage?

BackgroundThe radiology features of CT can be used to predict the development of hemorrhage. Purpose: To explore the relationship between regularity and the expansion of hematoma by using a novel factor: surface regulation. Methods: This is a retrospective study, where 213 patients (71 females, 33.3 %) are retrospectively analyzed. The inclusion criteria are as follows. The diagnosis of spontaneous supratentorial hemorrhage, admission CT scan and a cranial CT scan obtained within 9 h are required, with other potential causes of intracerebral hemorrhage excluded during hospitalization. The exclusion criteria are as follows. Any patients having operative treatment before the cranial CT scan are excluded. Then, they are divided into the hematoma expansion group based on expanded hematoma (relative growth ≥ 33 % or absolute growth ≥ 6 ml) and the non-hematoma expansion group. After other factors are balanced through a 1:2 PS match, 82 samples (31 females, 37.8 %) are modeled to calculate their surface area and volume by using 3D Slicer and their surface regularity [SR=6√πvolume√surfacearea3]. Results: The mean ± SD SR value of Group-HE is calculated to be 0.557 ± 0.131, while that of Group-NHE is calculated to be 0.631 ± 0.101. The effect of surface regulation on the expansion of intracerebral hemorrhage hematoma is found to be statistically significant (OR 0.004, 95 %CI 0.00–0.27, P = 0.011). Conclusions: There is a link between surface regularity and hematoma expansion during the early stages of intracerebral hemorrhage.

Glossopharyngeal Neuralgia following Coronavirus Disease 2019 Infection

Abstract Glossopharyngeal neuralgia is a rare and painful syndrome that affects the sensory distribution of the glossopharyngeal nerve. Coronavirus disease 2019 (COVID-19) was first discovered in the Wuhan province of China in November 2019 and was declared a pandemic by the World Health Organization in early 2020. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus strain that was responsible for COVID-19, may affect the central nervous system and cause neurological manifestations. We report a case of a 46-year-old female presenting with pain in her right ear and pharynx on swallowing, coughing, and sneezing. On physical examination, normocephaly, normal hearing, no oropharyngeal lesions, and bilaterally normal tonsils were observed. On neurologic examination, her speech was fluent without any abnormalities and testing revealed COVID-19 positivity. Cranial computed tomography scan, brain and spinal magnetic resonance imaging (MRI), cranial magnetic resonance angiogram, and soft-tissue neck MRI with and without contrast were unremarkable. Carbamazepine was initiated for neuropathic pain with success. Heightened awareness and early recognition of neurological complications related to SARS-CoV-2 infection may improve the prognosis. Monitoring the long-term nervous system complications of SARS-CoV-2 infection, including psychological and neurocognitive domains, is also necessary.

Cerebral infarct induced by severe leptospirosis-a case report and literature review

BackgroundAlthough most leptospirosis is mild, the severe form can cause multiple complications, with a fatality rate of over 50% even with ICU support. The clinical manifestations of leptospirosis vary depending on organs and tissues involved. Both cerebral artery and coronary artery can be damaged by leptospirosis. Although cerebral arteritis induced by leptospirosis has been reported, cerebral infarction caused by leptospirosis is rarely reported.Case presentationWe report the case of a 79-year-old man admitted to intensive care unit (ICU) because of 3 days duration of fever, bloody sputum and dyspnea. Five days before he was admitted to hospital, he had harvested rice in flooded fields. After admission, leptospira interrogans DNA sequence was identified in bronchoalveolar lavage fluid (BALF) by next-generation sequencing (NGS). Microscopic agglutination test (MAT) showed the serum antibody of Mini serovars was 1,600 and Hebdomadis serovars was 800. On the eighth day of admission, the patient noted left hemiplegia. Cranial CT scan revealed low-density shadow in the right basal ganglia, so cerebral infarction was diagnosed. The patient’s condition rapidly deteriorated and he died on the eleventh day of admission despite penicillin treatment, invasive mechanical ventilation and continuous renal replacement support.ConclusionNeurologic leptospirosis manifested as cerebral occlusion, although rare, might be deadly and should not be ignored.

Prognostic values of optic nerve sheath diameter for comatose patients with acute stroke: An observational study.

Optic nerve sheath diameter (ONSD) measurement is one of the non-invasive methods recommended for increased intracranial pressure (ICP) monitoring. This study aimed to evaluate the roles of optic nerve sheath diameter (ONSD) and ONSD/eyeball transverse diameter (ETD) ratio in predicting prognosis of death in comatose patients with acute stroke during their hospitalization. A total of 67 comatose patients with acute stroke were retrospectively recruited. The ONSD and ETD were measured by cranial computed tomography (CT) scan. All patients underwent cranial CT scan within 24 h after coma onset. Patients were divided into death group and survival group according to their survival status at discharge. The differences of the ONSD and ONSD/ETD ratio between the two groups and their prognostic values were compared. The ONSD and ONSD/ETD ratio were 6.07 ± 0.72 mm and 0.27 ± 0.03 in the comatose patients, respectively. The ONSD was significantly greater in the death group than that in the survival group (6.32 ± 0.67 mm vs 5.65 ± 0.62 mm, t = 4.078, P < 0.0001). The ONSD/ETD ratio was significantly higher in the death group than that in the survival group (0.28 ± 0.03 vs 0.25 ± 0.02, t = 4.625, P < 0.0001). The area under the receiver operating characteristic curve was 0.760 (95%CI: 0.637-0.882, P < 0.0001) for the ONSD and 0.808 (95%CI: 0.696-0.920, P < 0.0001) for the ONSD/ETD ratio. The mortality increased in comatose patients with acute stroke when the ONSD was > 5.7 mm or the ONSD/ETD ratio was > 0.25. Both indexes could be used as prognostic tools for comatose patients with acute stroke. The ONSD/ETD ratio was more stable than the ONSD alone, which would be preferred in clinical practice.

Numerical and experimental evaluation of low-intensity transcranial focused ultrasound wave propagation using human skulls for brain neuromodulation.

Low-intensity transcranial focused ultrasound (tFUS) has gained considerable attention as a promising noninvasive neuromodulatory technique for human brains. However, the complex morphology of the skull hinders scholars from precisely predicting the acoustic energy transmitted and the region of the brain impacted during the sonication. This is due to the fact that different ultrasound frequencies and skull morphology variations greatly affect wave propagation through the skull. Although the acoustic properties of human skull have been studied for tFUS applications, such as tumor ablation using a multielement phased array, there is no consensus about how to choose a single-element focused ultrasound (FUS) transducer with a suitable frequency for neuromodulation. There are interests in exploring the magnitude and dimension of tFUS beam through human parietal bone for modulating specific brain lobes. Herein, we aim to investigate the wave propagation of tFUS on human skulls to understand and address the concerns above. Both experimental measurements and numerical modeling were conducted to investigate the transmission efficiency and beam pattern of tFUS on five human skulls (C3 and C4 regions) using single-element FUS transducers with six different frequencies (150-1500kHz). The degassed skull was placed in a water tank, and a calibrated hydrophone was utilized to measure acoustic pressure past it. The cranial computed tomography scan data of each skull were obtained to derive a high-resolution acoustic model (grid point spacing: 0.25mm) in simulations. Meanwhile, we modified the power-law exponent of acoustic attenuation coefficient to validate numerical modeling and enabled it to be served as a prediction tool, based on the experimental measurements. The transmission efficiency and -6dB beamwidth were evaluated and compared for various frequencies. An exponential decrease in transmission efficiency and a logarithmic decrease of -6dB beamwidth with an increase in ultrasound frequency were observed. It is found that a >750kHz ultrasound leads to a relatively lower tFUS transmission efficiency (<5%), whereas a <350kHz ultrasound contributes to a relatively broader beamwidth (>5mm). Based on these observations, we further analyzed the dependence of tFUS wave propagation on FUS transducer aperture size. We successfully studied tFUS wave propagation through human skulls at different frequencies experimentally and numerically. The findings have important implications to predict tFUS wave propagation for ultrasound neuromodulation in clinical applications, and guide researchers to develop advanced ultrasound transducers as neural interfaces.

The Complete and Two-Turn Cochlear Duct Length Among Filipinos

&#x0D; &#x0D; &#x0D; &#x0D; ABSTRACTObjective: This study aims to measure the complete and two-turn cochlear duct lengths in a Filipino population using archived CT scan images.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Methods: &#x0D; Design: Retrospective Review of Records&#x0D; Setting:Tertiary Government Training Hospital&#x0D; Participants: CT Scan Images of 255 patients&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Cochlear images of patients who underwent cranial, facial, orbital, paranasal sinus and temporal bone CT scans from January 2019 to December 2019 were analyzed. Coronal oblique images from 3D multiplanar reconstructions were obtained and a single linear measurement (‘A’ value) was used as the spiral coefficient to calculate the complete cochlear duct length (CDL) and two- turn length (2TL).&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Results: A total of 510 cochlear images were obtained from the CT scan images of 255 subjects (143 males, 112 females aged 1 to 81 years; mean age = 47 years). The mean ‘A’ value was 8.81 mm (SD = 0.20). The mean complete cochlear duct length was 32.68 mm (31.01 mm – 35.50 mm; SD = 0.834) while the mean two-turn cochlear duct length was 29.61 mm (28.14 mm – 32.08 mm; SD = 0.732). The complete and two-turn cochlear duct lengths in males were found to be significantly longer than in females (p = .001). No significant difference was found between cochlear measurements for left and right ears.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Conclusion: The mean complete cochlear duct length among Filipinos in our study measures 32.68 mm while the mean two-turn cochlear duct length measures 29.61mm. Both complete and two-turn cochlear duct lengths were longer among Filipino males than among females.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Hearing Loss from S. Suis Meningitis In A Middle-Aged Couple

Hearing Loss from S. Suis Meningitis In A Middle-Aged Couple