Neuroimaging for Early Diagnosis of Alzheimer's Disease: a Review.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disease that primarily affects people above the age of 60 all around the world. As of now, the cause is unknown and there is no effective cure. The pathological changes of AD have occurred many years before the onset of the disease, and current treatment techniques can only delay the progression of the disease. Because disease-modifying therapies may be most beneficial in the early stages of AD, the clinical significance of an early diagnosis is emphasized. So far, a variety of imaging technologies and related biomarkers have been used to identify and monitor AD, but there are many imaging technologies; finding the most effective imaging technology can assist medical personnel in interpreting the early stages of AD and can also improve patient treatment opportunities. This is, therefore, the main purpose and back-ground of this study. METHODS: PubMed and other repositories were used in this study to conduct a literature search with various keywords, and relevant articles were reviewed. In this review, different neuroimaging techniques are reviewed which are considered advanced tools to help establish the diagnosis, and in addition, the diagnostic utility, advantages, and limitations of contemporary AD imaging techniques are discussed. RESULTS: The results of the literature review and synthesis show that the prevalence of several in vivo biomarkers helps distinguish affected individuals from healthy controls in the early stages of the disease. Additionally, each current imaging method has its advantages and disadvantages, so no single imaging method is the best diagnostic modality. CONCLUSIONS: This article also reviews and draws conclusions on better ways to use the imaging techniques to improve the likelihood of an early diagnosis of AD. It is suggested that future research could focus on expanding the use of imaging technologies and on identifying novel biomarkers manifesting the earliest stages of AD pathology.

Grey matter alterations in generalized anxiety disorder: A voxel-wise meta-analysis of voxel-based morphometry studies.

OBJECTIVE: Grey matter, a crucial component of the brain, has been found altered in generalized anxiety disorder (GAD) of several voxel-based morphometry studies. The conclusive and consistent grey matter alterations in GAD have not been confirmed. METHOD: Eleven voxel-based morphometry studies of GAD patients were included in the current systematic review and meta-analysis. The linear model of anxiety severity scores was applied to explore the relationship of grey matter alterations and anxiety severity. The subgroup analysis of adult GAD and adolescent GAD was also performed. RESULTS: Significantly modest grey matter alterations in the left superior temporal gyrus of patients with GAD were found. The anxiety severity score was significantly correlated with grey matter alterations in the right insula, lenticular nucleus, putamen and striatum. The subgroup analysis of adult GAD and adolescent GAD all failed to show significant grey matter alterations. However, in the adult GAD subgroup, anxiety severity score was significantly correlated with grey matter alterations in the right insula. CONCLUSION: GAD might have the modest grey matter alterations in the left superior temporal gyrus. Anxiety severity might be related to the grey matter alterations in the limbic regions, such as the right insula, lenticular nucleus, putamen and striatum. This kind of correlation might be related to the effects of adult GAD. Future studies with adequate sample sizes and sophisticated GAD categories will be needed.

Monorail snare technique for retrieval of stretched coil.

Coil stretching is a recognized complication during cerebral aneurysm embolization.1, 3- 5 For over a decade, the microsnare has proven effective in retrieving migrated coils.1- 5 Fiorella et al. unveiled the "Monorail Snare Technique" in 2005, offering a specialized approach to stretched coil recovery.1 However, to gain a complete understanding of this technique, more than just textual descriptions are necessary; a thorough, practical demonstration is essential. In our technical video (video 1), we illustrated an episode of coil stretching during aneurysm embolization, where the "Monorail Snare Technique" was successfully employed to retrieve a stretched coil. Our video emphasizes the meticulous preparation and modification of the microsnare, showcasing enhanced steps to mitigate the potential blood backflow triggered by the exclusive use of one-arm hemostasis valve during the "Monorail Snare Technique."1, 5 This pivotal adjustment substantially lowers the threat of thromboembolic events. We highlighted essential precautions to ensure the procedure's safety and efficacy.4, 5.

Radiographical presentations of inadvertent subdural placement of an epidural catheter for successful labor analgesia: A case report.

RATIONALE: Lumbar epidural analgesia is the gold standard for labor pain control. However, misplacement of epidural catheters into the subdural space may inadvertently happen. Unrecognized subdural administration of local anesthetics could result in serious consequences, including high spinal and brainstem blocks. This case report describes a case where subdural epidural catheter placement was recognized early but labor pain was adequately managed by dosage titration of subdural analgesia. PATIENT CONCERNS: This case report describes a 29-year-old primiparous pregnant woman who was admitted to our obstetric unit for labor induction at the gestational age of 38 weeks. An epidural catheter was inserted via the L2-3 intervertebral space using the standard loss of resistance to air technique. DIAGNOSES: The parturient experienced weakness in the lower extremities and numbness in the upper extremities within 15 minutes after administration of 5 mL of 2% v/v lidocaine as a loading dose and systolic blood pressure also dropped by 25%. INTERVENTIONS: The dose regimen (a mixture of 0.1% ropivacaine and 4 µg/mL fentanyl) for patient-controlled analgesia was given with bolus doses of 0.1 mL per demand and lockout intervals of 20 minutes. The analgesic effects were adequately maintained below the T8 dermatome for more than 12 hours without hypotensive episodes or obvious signs of neurological deficits. Computed tomographic myelography was performed by instillation of a nonionic iodinated contrast medium via the epidural catheter on postpartum day 2 for imaging confirmation of catheter placement in the extradural space. LESSONS: Early recognition that epidural catheters for neuraxial analgesia have been inserted into the subdural space is important for the prevention of high spinal blocks. Subdural analgesia could still be achieved by careful clinical assessment and titration of low analgesic doses. This report also presents important and clear serial computed tomographic images of catheter placement in the thoracic-lumbar subdural spaces and the extent of volume spread in the subdural space following administration of contrast medium.

Coil embolization of distal vascular lesion using a 1.5 Fr Marathon microcatheter and 'free-running' technique.

In distal vascular lesions, such as the distal anterior inferior cerebellar artery or posterior inferior cerebellar artery (PICA) dissecting aneurysm, and dural arteriovenous fistula (dAVF) and arteriovenous malformation (AVM), super-selective catheterization and embolization using liquid agents, such as NBCA or Onyx liquid embolic system, is the preferred treatment.1 2 We used a flow-directed 1.5 Fr Marathon microcatheter (Medtronic, Minneapolis, MN, USA) for embolization because commonly used detachable coil-compatible microcatheters can be too short or rigid for superselection.3-6 We designed an in vitro coil compatibility test for the Marathon microcatheter and developed a 'free-running' technique (video 1). Using this technique, we trapped the distal PICA dissecting aneurysm and embolized the fistula points of dAVF precisely and safely without affecting adjacent normal structures, which can occur when applying liquid embolizing agents.1-3 After reviewing the case, we determined that this technique can also potentially be applied for implementing the pressure cooker technique7 and combining the management of AVM.4neurintsurg;jnis-2023-020893v1/V1F1V1Video 1Free-running technique via 1.5 Fr Marathon microcatheter.

Treatment, Outcome, and Relapse of Spontaneous and Nonspontaneous Cerebrospinal Fluid Leak.

Cerebrospinal fluid (CSF) leak can be spontaneous or nonspontaneous. The management options include conservative treatments, blood patch, and surgical repairs. We compared clinical symptoms, image findings, management options, hospitalization, and relapse rates among different causes of CSF leaks. Eighty-one patients were recruited: 20 with spontaneous and 61 with nonspontaneous CSF leaks. Nonspontaneous causes included lumbar puncture, surgery, and trauma. Surgery sites comprised sphenoid, spine, skull base, and calvaria. Spontaneous CSF leak came from the sphenoid or spine. Age, gender, body mass index, initial symptoms, hospitalization, treatment courses, and recurrence rates showed no difference between the groups. The spontaneous group had higher CSF accumulations on their MRIs. MRI pachymeninge enhancement showed the highest sensitivity (78.6%) for intracranial hypotension. Meningitis occurred in 1/3 of sphenoid, skull base, and calvarian surgeries. Earlier reoperation was correlated with shorter hospitalization (r = 0.651), but the recurrence rates were similar. Longer intervals between surgery and CSF leak encouraged reoperation. Among the spontaneous spine and lumbar puncture-related CSF leaks, 57.1% of them responded to 4 days of conservative treatment. Among the trauma-related CSF leaks, 90.9% of them required surgical repair. The demographic data and symptoms were similar in various groups of CSF leak. The symptom onset durations and treatment strategies were different. However, the recurrence rates were similar.

Transvenous embolization of a direct carotid-cavernous fistula through the pterygoid plexus approach.

We present a transvenous embolization technique for a direct carotid-cavernous fistula through the pterygoid plexus to the cavernous sinus which only 2 cases have been previously reported in the English literature. This method is appropriate when transarterial techniques or other attempts at transvenous access have failed due to vessel tortuosity, hypoplasia, stenosis, or occlusion. A middle-aged female patient presented with progressive left exophthalmos with conjunctiva chemosis and bruit after sustaining a falling injury. Digital subtraction angiography revealed Barrow type A carotid-cavernous fistula. The drainage route passed through a distal thrombosed superior ophthalmic vein that ended deep in the orbit. No other patent venous sinuses connected to the cavernous sinus, except for a small tract of pterygoid plexus. After failure of transarterial approach and other methods of transvenous access, we attempted to superselectly access to the cavernous sinus by applying transpterygoid technique with embolization using detachable coils. The transpterygoid venous approach to accessing the cavernous sinus represents an alternative approach when other techniques fail.

Lhermitte-Duclos disease: A case report with radiologic-pathologic correlation.

Background: Lhermitte-Duclos disease (LDD) stems from the development of a rare benign lesion of uncertain pathogenesis that distorts the normal cerebellar laminar cytoarchitecture. We explored the lesion's appearance on conventional magnetic resonance imaging (MRI) combined with susceptibility-weighted imaging, diffusion-weighted imaging, perfusion imaging, or arterial spin labeling. Although many cases of LDD have been previously reported in the literature, the radiologic-pathologic correlation has been described in only a few of these cases. To the best of our knowledge, this is the first case report to provide detailed information about the radiologic-pathologic correlation of LDD. Case Report: A 48-year-old woman presented with left facial tics, occipital headache, and dizziness for 1 month. MRI revealed a left cerebellar lesion with hypointensity on T1-weighted images. On T2-weighted images, the mass was hyperintense with tigroid appearance due to alternating high and normal signal intensities. High signal intensity was noted on fluid-attenuated inversion recovery images. Magnetic resonance spectroscopy indicated decreased level of choline (Cho), N-acetyl aspartate, and myoinositol with elevated level of lactate on the affected side. The lesion showed a bright signal on diffusion-weighted images, whereas apparent diffusion coefficient mapping revealed no disturbance of diffusion. The pathology of the excised lesion was consistent with LDD. Conclusion: MRI with advanced techniques can provide not only preoperative diagnosis but also better pathologic correlation.

Quantitative flow measurement after placing a flow diverter for a distal internal carotid artery aneurysm.

OBJECTIVES: To evaluate the differences in arterial flow after flow diverter placement using quantitative flow measurements based on digital subtraction angiography (DSA). METHODS: Between November 2013 and November 2015, all patients who had flow diverters placed for distal internal carotid artery (ICA) aneurysms were reviewed. Patients in whom the stent was placed across the ostia of the ophthalmic artery (OphA) and anterior choroidal artery (AChA) were enrolled. Five regions of interest were selected: the proximal ICA (as a reference), terminal ICA, middle cerebral artery (MCA), anterior cerebral artery (ACA), OphA, and AChA. The values of the peak, time-to-peak (TTP), and area under the curve (AUC) were analyzed using a quantitative DSA technique. RESULTS: The study enrolled 13 patients. The quantitative flow analysis showed improved flow in the terminal ICA (peak and AUC, p=0.036 and p=0.04, respectively), MCA (AUC, p=0.023), and ACA (AUC, p=0.006), and decreased flow in the OphA (peak and AUC, p=0.013 and p=0.005, respectively) and AChA (peak and subtracted TTP, p=0.023 and p=0.050, respectively) after flow diverter placement. Larger aneurysm volume was significantly correlated with decreased OphA flow after the procedure (peak and AUC, p=0.049 and p=0.037, respectively). Larger aneurysm volume also had a marginal correlation with increased distal ICA flow after the procedure, but this did not reach significance (peak and AUC, p=0.195 and p=0.060, respectively). CONCLUSIONS: Without using extra contrast medium or radiation dosages, color-coded DSA enables quantitative monitoring of the cerebral circulation after flow-diverting treatment.

Spinal intraosseous epidural arteriovenous fistula with perimedullary drainage obliterated with Onyx embolization: case report.

The authors report an extremely rare case of spinal intraosseous epidural arteriovenous fistula (AVF) with perimedullary vein reflux causing symptoms of myelopathy. The intraosseous fistula tracts were completely obliterated with Onyx embolic agent, resulting in a total resolution of symptoms. The unique features of this case include the rare location of the fistula in the vertebral body and the association of the fistula with a compressive fracture. Imaging studies confirmed these hemodynamic findings and provided clarity and direct evidence regarding the association of epidural AVF formation with the vertebral compressive fracture. The authors also propose a possible disease evolution based on the previously adduced reflux-impending mechanism.

Acute spontaneous subdural hematoma caused by skull metastasis of hepatocellular carcinoma: case report.

BACKGROUND: Skull and intracranial metastases from hepatocellular carcinoma (HCC) have seldom been reported. A skull metastasis of HCC with a tumor bleeding resulting in spontaneous subdural hematoma (SDH) is extremely unusual. We report the first case of acute spontaneous SDH in a 69-year-old woman who presented with acute onset of headache, because of tumor bleeding caused by skull metastasis of HCC. CASE PRESENTATION: A 69-year-old woman was referred to our hospital because of progressive headache, nausea, and vomiting for 3 days. Brain computed tomography (CT) performed in the emergency department (ED) revealed a left temporal SDH with a slight mass effect and a small left temporal bone erosion. Tri-phasic abdominal CT demonstrated a large right lobe liver tumor compatible with HCC. She experienced progressive deterioration of consciousness in the intensive care unit. Follow-up CT showed an enlargement of the SDH. An emergency craniotomy for hematoma evacuation and removal of skull tumor was performed. She regained consciousness and had no neurological deficits during the postoperative course. Pathological examination of the skull specimen indicated metastasis of a HCC. CONCLUSION: Patients with acute SDH without a history of head injury are rarely encountered in the ED. Metastatic carcinoma with bleeding should be included as a differential diagnosis for acute spontaneous SDH. Before an operation for SDH, the possibility of metastatic lesion of the skull should be considered in the surgical planning and the origin of malignancy should be sought.

Complex coil assisted single coil embolization for small intracranial aneurysm.

The purpose of the technical note is to introduce the complex coil assisted coil embolization method in the treatment of intracranial small aneurysm, in order to enhance the safety of the procedure. The first microcatheter was navigated into the aneurysm sac and the ultrasoft coil was used as the embolization coil. If the embolizations coil could not stay within the aneurysm sac smoothly, such as coil herniation into parent artery during the delivery process. The second microcatheter would be navigated to the aneurysm level in the parent artery. Another complex coil was delivered within the parent artery via the second microcatheter to provide the neck bridge effect in order to enhance the stability of embolization coil. Besides, the protection coil will not disturb the parent artery flow. While the embolization coil was put into the aneurysm sac smoothly under the help of complex protective coil, the protective coil was then withdrawn gently. We use the most magnified view, dual-plane approach simultaneously to observe the stability of embolization coil. The embolization coil would be detached without any evidence of coil motion or vibration. The new method could provide the physiological protective method, without leaving any protective device such as stent within the parent artery.

Iatrogenic and fatal arterial air embolism during the CT scan.

Systemic and fatal arterial air embolism during the computed tomography (CT) scan is rarely reported in English-based literature. Iatrogenic air embolism happening during the CT scan is often related to the injector, usually venous air embolism and asymptomatic. We report one fatal and extensive systemic arterial air embolism because of one error that happened during a brain CT scan. The mechanism is different from the reported cases in the literature. The possible mechanism and pathogenesis are well discussed to alert clinicians and prevent the recurrence of such complication.

Preoperative embolization of carotid body tumor by direct percutaneous intratumoral injection of N-butyl cyanoacrylate glue assisted with balloon protection technique.

Substantial intraoperative bleeding during surgical removal of carotid body tumor may be a major problem in the management of these highly vascularized tumors. Traditional preoperative embolization via a transarterial access has proved effective but is often limited by complex vascular anatomy and small feeding vessels that is difficult to catheterize. We report two cases of carotid body tumor treated with direct puncture and intratumoral injection of N-butyl cyanoacrylate glue (NBCA) assisted with balloon protection technique for preoperative devascularization. The result was impressive and minimal bleeding loss during surgery was observed.

Percutaneous direct puncture embolization for superficial craniofacial arteriovenous malformation.

SUMMARY: Endovascular embolization for craniofacial arteriovenous malformation has been used as preoperative adjuvant devascularization or as definitive therapy. However, because the vascular network is complex, embolization via arterial access may be ineffective, risky, incomplete or technically difficult. The purpose of this report is to describe our experience of percutaneous direct venous pouch puncture embolization. Four patients with craniofacial AVMs were treated with direct puncture embolization via injection of NBCA. After the selective transarterial angiogram, the lesions were directly punctured in the venous pouch under a road map angiogram. A glue mixture was injected, and post-embolization angiograms revealed that in all patients, the lesions had been completely obliterated without complication. Percutaneous direct puncture embolization is an effective, time saving and safe technique for the superficial craniofacial AVM with prominent venous pouch.

"Waffle cone"technique for intra/extra-aneurysmal stent placement for the treatment of complex and wide-necked bifurcation aneurysm.

SUMMARY: Endovascular treatment of intracranial aneurysms by coiling has become an accepted alternative to surgical clipping (1). In cases of wide-necked and sidewall aneurysms, selective embolization is difficult because of the risk of coil protrusion into the parent vessel. The use of three-dimensional coils, stents (2), and balloon remodeling have all aided the attempt to adequately manage such lesions. However, compared with sidewall aneurysms, bifurcation aneurysms are more challenging from an endovascular standpoint. Because of their specific anatomy and hemodynamics, the tendency to recur and rerupture is higher. Several authors have reported successful treatment of these complex and wide-necked bifurcation aneurysms by using Yconfigured dual stent-assisted coil embolization (3,4), the double microcatheter technique (5), a more compliant balloon remodeling technique (6), the TriSpan neck-bridge device (7), or the waffle cone technique (8).We describe two cases of widenecked bifurcation aneurysms in which the waffle cone technique was used for coil embolization. The waffle cone technique was first described in 2006; however, the small number of published cases and the lack of follow-up prevent one from assessing this technique's durability and the probability of recanalization.We report the cases of two patients harboring unruptured wide-necked bifurcation aneurysms that were treated and followed-up for six months.

Nasal NK/T-cell lymphoma: computed tomography and magnetic resonance imaging findings.

BACKGROUND: Primary nasal natural killer (NK)/T-cell lymphoma is the most common cellular subtype seen in nasal lymphomas. It is rare in the Western population but occurs more frequently in Asia, South America, and Mexico. The purpose of this study was to describe the computed tomography (CT) and magnetic resonance (MR) imaging findings of primary nasal NK/T-cell lymphoma. METHODS: During the period between January 1990 and June 2006, the CT (n=24) and MR (n=6) images of 24 patients with biopsy-proved nasal NK/T-cell lymphoma were reviewed retrospectively. Both CT and MR images were evaluated for site and extent of disease and for pattern of involvement of adjacent areas. RESULTS: The most common symptoms at presentation were nasal obstruction, nasal discharge, and epistaxis. There was involvement of the unilateral nasal cavity in 16, bilateral nasal cavity including nasal septum in 5 and nasal choana in 3. Sites of extension outside the nasal cavity included tumor extension into paranasal sinuses (n=15), nasopharynx (n=5), nasal labial fold (n=3), oropharynx (n=2), infratemporal fossa (n=2), other subcutaneous soft tissue of the face (n=2) and anterior cranial fossa base (n=1). Bony destruction was demonstrated in 18 cases, involving the sinus bony wall (n=15), nasal turbinate (n=10), lamina papyracea (n=6), orbital floor (n=3), and hard palate (n=2). Regional lymphadenopathy was also detected in 3 patients with nasal NK/T-cell lymphoma. CONCLUSION: The CT and MR appearances of nasal NK/T-cell lymphoma are nonspecific, and the diagnosis requires histologic confirmation. However, the differential diagnosis of nasal NK/T-cell lymphoma should be included if the images present soft tissue of the nasal cavity with bony erosion or destruction; involvement of the orbital cavity, nasopharynx and infratemporal fossa; and subcutaneous or nasolabial fold soft tissue infiltration, especially in Asian populations.