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Purpose: To assess patient radiation doses during diagnostic and therapeutic neurointerventional procedures from multiple centers and propose dose reference level (RL).Materials and Methods: Consecutive neurointerventional procedures, performed in 22 hospitals from December 2020 to June 2021, were retrospectively studied. We collected data from a sample of 429 diagnostic and 731 therapeutic procedures. Parameters including dose-area product (DAP), cumulative air kerma (CAK), fluoroscopic time (FT), and total number of image frames (NI) were obtained. RL were calculated as the 3rd quartiles of the distribution.Results: Analysis of 1160 procedures from 22 hospitals confirmed the large variability in patient dose for similar procedures. RLs in terms of DAP, CAK, FT, and NI were 101.6 Gy·cm2, 711.3 mGy, 13.3 minutes, and 637 frames for cerebral angiography, 199.9 Gy·cm2, 3,458.7 mGy, 57.3 minutes, and 1,000 frames for aneurysm coiling, 225.1 Gy·cm2, 1,590 mGy, 44.7 minutes, and 800 frames for stroke thrombolysis, 412.3 Gy·cm2, 4,447.8 mGy, 99.3 minutes, and 1,621.3 frames for arteriovenous malformation (AVM) embolization, respectively. For all procedures, the results were comparable to most of those already published. Statistical analysis showed male and presence of procedural complications were significant factors in aneurysmal coiling. Male, number of passages, and procedural combined technique were significant factors in stroke thrombolysis. In AVM embolization, a significantly higher radiation dose was found in the definitive endovascular cure group.Conclusion: Various RLs introduced in this study promote the optimization of patient doses in diagnostic and therapeutic interventional neuroradiology procedures. Proposed 3rd quartile DAP (Gy·cm2) values were 101.6 for diagnostic cerebral angiography, 199.9 for aneurysm coiling, 225.1 for stroke thrombolysis, and 412.3 for AVM embolization. Continual evolution of practices and technologies requires regular updates of RLs.

Purpose To assess patient radiation doses during cerebral angiography and embolization of intracranial aneurysms across multi-centers and propose a diagnostic reference level (DRL). Materials and Methods We studied a sample of 490 diagnostic and 371 therapeutic procedures for intracranial aneurysms, which were performed at 23 hospitals in Korea in 2015. Parameters including dose-area product (DAP), cumulative air kerma (CAK), fluoroscopic time and total angiographic image frames were obtained and analyzed. Results Total mean DAP, CAK, fluoroscopy time, and total angiographic image frames were 106.2 ± 66.4 Gy-cm2, 697.1 ± 473.7 mGy, 9.7 ± 6.5 minutes, 241.5 ± 116.6 frames for diagnostic procedures, 218.8 ± 164.3 Gy-cm2, 3365.7 ± 2205.8 mGy, 51.5 ± 31.1 minutes, 443.5 ± 270.7 frames for therapeutic procedures, respectively. For diagnostic procedure, the third quartiles for DRLs were 144.2 Gy-cm2 for DAP, 921.1 mGy for CAK, 12.2 minutes for fluoroscopy times and 286.5 for number of image frames, respectively. For therapeutic procedures, the third quartiles for DRLs were 271.0 Gy-cm2 for DAP, 4471.3 mGy for CAK, 64.7 minutes for fluoroscopy times and 567.3 for number of image frames, respectively. On average, rotational angiography was used 1.5 ± 0.7 times/session (range, 0-4; n=490) for diagnostic procedures and 1.6 ± 1.2 times/session (range, 0-4; n=368) for therapeutic procedures, respectively. Conclusion Radiation dose as measured by DAP, fluoroscopy time and image frames were lower in our patients compared to another study regarding cerebral angiography, and DAP was lower with fewer angiographic image frames for therapeutic procedures. Proposed DRLs can be used for quality assurance and patient safety in diagnostic and therapeutic procedures.

Metabolic encephalopathy is a critical condition that can be challenging to diagnose. Imaging provides early clues to confirm clinical suspicions and plays an important role in the diagnosis, assessment of the response to therapy, and prognosis prediction. Diffusion-weighted imaging is a sensitive technique used to evaluate metabolic encephalopathy at an early stage. Metabolic encephalopathies often involve the deep regions of the gray matter because they have high energy requirements and are susceptible to metabolic disturbances. Understanding the imaging patterns of various metabolic encephalopathies can help narrow the differential diagnosis and improve the prognosis of patients by initiating proper treatment regimen early.

Metronidazole-induced encephalopathy is a rare neurologic adverse effect of an antibiotic drug ‘metronidazole’. Although it is usually reversible with immediate cessation of the drug, it can also be fatal when used continuously. Here, we present a 72- year-old female who was on metronidazole for a total of 46 consecutive days. Her initial MRI on the 22nd day of medication use revealed a typical involvement of the cerebellar dentate nuclei, corpus callosum splenium, and periaqueductal midbrain, suggesting metronidazole-induced encephalopathy. However, she continued the medication for another 24 days, until she revisited our emergency department with mental status change. Her consecutive MRI showed diffuse cerebral and brainstem involvement, as well as a more prominent involvement of the dentate nuclei and splenium. We present this case to highlight that it is possible for metronidazole-induced toxic encephalopathy to worsen without immediate withdrawal of the offending drug.

Cerebral hyperperfusion syndrome (CHS) is serious complication after carotid artery stenting (CAS) caused by decreased cerebral vasoreactivity (CVR) due to long standing hypoperfusion of the brain. We hypothesized that partial dilatation of carotid stenosis would allow the recovery of CVR, and prevent CHS when definitive angioplasty with stent is performed afterward. In this study, we aimed to evaluate the safety and efficacy of staged CAS in patients with severe carotid artery stenosis with evident hemodynamic compromise in regard to preventing hyperperfusion syndrome. From January 2005 to February 2016, 53 patients with 55 severe carotid artery stenosis lesions showing decreased CVR and/or cerebral basal flow at the perfusion studies underwent staged CAS in three institutes. The procedure consisted of initial partial balloon angioplasty (BA), recovery period, and delayed definitive stenting (DS). We analyzed immediate results, complications, recoil and CHS related to staged CAS. We experienced no symptomatic manifestation of CHS except self-limited headache after the procedures. The median of intervals between BA and DS stages were 10 days. There was no case of severe recoil during the interval between BA and DS stage. Where perfusion imaging data was available, hyperperfusion was present in three and one patients after BA and DS stage, respectively, with no clinical symptom of CHS. In conclusion, staged CAS was feasible in patients with severe carotid artery stenosis and hemodynamic compromise, without inducing severe complication of CHS such as intracranial hemorrhage.

Posterior reversible encephalopathy syndrome (PRES) is characterized by clinical symptoms that are associated with bilateral and symmetric vasogenic edema in the parietal and occipital lobes. However, this is rarely present with predominant involvement of the brain stem and cerebellum (variant).To evaluate which clinical or magnetic resonance imaging (MRI) findings can help to predict the prognosis of variant and classical type of PRES and whether or not there is difference between two types of PRES.We retrospectively evaluated MRI and clinical findings from 49 patients with PRES. These patients were divided into two groups. In group I, patients had atypical distribution of lesions. In group II, patients had typical distribution of lesions. Follow-up MRI was performed on 26 patients. We assessed the MRI features, clinical data, and the patients' outcomes.The mean blood pressure (BP) was significantly higher in group I (195.52/121.09 mmHg and 156.78/99.53 mmHg for groups I and II, respectively). The other factors assessed were not significantly different between the two groups. Lesions in 24 of 26 patients reversed upon follow-up. Sequelae were observed in 11 patients (group I, 7; group II, 4). However, there were no significant differences between the two groups. Except for those patients who died, seven of the nine patients with sequelae upon follow-up imaging had hemorrhage or irreversibility of lesions.Even though BP influences the involvement of the brain stem, involvement of the brain stem is not influential on the prognosis. It seems that the influential factor to prognosis is the reversibility of lesions and hemorrhage.

Moyamoya disease is a rare cerebrovascular disorder that is characterized by progressive stenosis of the distal portion of the internal carotid artery and its main branches. Here the authors present the first case of spontaneous recanalization of an occluded middle cerebral artery in a woman with moyamoya who had not undergone surgical or endovascular treatment. Although the exact mechanisms remain unclear, spontaneous recanalization in moyamoya could be considered a possible phenomenon. Thus, the neurosurgeons should always pay attention to the pathological variety of dynamic changes in the cerebrovascular structure in moyamoya.

Primary germ cell tumor (GCT) in the pineal region is very rare among all primary intracranial neoplasms. Here, we present the 18F-FDG PET/CT findings of a pineal mixed GCT in a 14-year-old boy. PET/CT showed little uptake of 18F-FDG in the mass in the pineal region, whereas MR imaging showed contra

Background and Purpose YKL-40 is associated with various neurological disorders. However, circulatory YKL-40 levels early after onset of acute ischemic stroke (AIS) have not been systematically assessed. We aimed to identify the temporal changes and clinical usefulness of measuring serum YKL-40 immediately following AIS. Methods Serum YKL-40 and C-reactive protein (CRP) levels were monitored over time in AIS patients (n = 105) and compared with those of stroke-free controls (n = 34). Infarct volume and stroke severity (National Institutes of Health Stroke Scale; NIHSS) were measured within 48 hours of symptom onset, and functional outcome (modified Rankin Scale; mRS) was measured 3 months after AIS. Results Within 12 hours of symptom onset, levels of YKL-40 (251 vs. 41 ng/mL) and CRP (1.50 vs. 0.96 µg/mL) were elevated in AIS patients compared to controls. The power of YKL-40 for discriminating AIS patients from controls was superior to that of CRP (area under the curve 0.84 vs. 0.64) and YKL-40 (r = 0.26, P

Haemangioblastoma is a slow-growing, highly vascular tumour and typically occurs in the cerebellum but can also occur in the brainstem and spinal cord. Because of their hypervascularity and location, cerebellar haemangioblastomas can be difficult to remove. The purpose of preoperative embolization of haemangioblastomas is to decrease the intraoperative blood loss and to facilitate excision. However, the safety and efficacy of this procedure remain controversial. Here, we report the case of a man with cerebellar haemangioblastoma who underwent preoperative embolization with Onyx. The tumour was completely removed with minimal tumour bleeding. There was no complication related to embolization.

Uremic encephalopathy is a well-known disease with typical MR findings including bilateral vasogenic or cytotoxic edema at the cerebral cortex or basal ganglia. Involvement of the basal ganglia has been very rarely reported, typically occurring in uremic-diabetic patients. We recently treated a patient who had non-diabetic uremic encephalopathy with an atypical lesion distribution involving the supratentorial white matter, without cortical or basal ganglia involvement. To the best of our knowledge, this is only the second reported case of non-diabetic uremic encephalopathy with atypical MR findings.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary microangiopathy caused by mutations in the Notch3 gene located on chromosome 19, leading to 4 cardinal features with aura, cerebrovascular ischemic events, mood disturbances, and dementia. Acetazolamide (ACZ) has been promoted as a drug to determine cerebral hemodynamics, including cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in patients with cerebrovascular disease. In CADASIL patients with small-vessel disease, ACZ may be possible to increase CBF. We present that reduced CBF was dramatically improved after administration of ACZ on Tc-99m ECD brain perfusion SPECT in a CADASIL patient.

Approximately 1--5% of the spinal schwannomas arise in the sacrum and frequently grow to a considerable size before becoming symptomatic; hence, the term “giant sacral schwannoma” refers to tumors extending into the vertebral body and the extraspinal space (1). Most schwannomas are solid or heterogeneous solid tumors, but they can rarely undergo cystic degeneration, xanthomatous change, or hemorrhage (2). A completely cystic appearance with only thin peripheral wall enhancement is extremely rare. A few cases of solitary cystic schwannomas arising from the spine have been previously reported (3-8). To the best of our knowledge, there is only one previous reported case of a giant solitary cystic schwannoma of the sacrum. Here, we describe a rare case of a totally cystic giant sacral schwannoma presenting as lumbar back pain. Institutional review board approval was obtained.

A subarachnoid hemorrhage (SAH) is caused by rupture of an intracranial aneurysm. SAHs have significant morbidity and mortality worldwide. Since the 1970s, clipping of intracranial aneurysms has been the standard treatment for SAHs. In the 1990s, a detachable platinum coil device was introduced. This device led to the development of endovascular techniques and reduced the risk of further rupture without a craniotomy. Thus, endovascular coiling has become widely used in patients with ruptured and unruptured intracranial aneurysms (UIAs). Regardless of the treatment technique (clipping or endovascular coiling), the goal of occluding aneurysms is the prevention of rebleeding in ruptured aneurysms and rupture in UIAs. These two treatment techniques have advantages and disadvantages. The question of which technique is more effective in patients with intracranial aneurysms remains controversial. The objective of this article is to provide a comprehensive review of the effect of coiling versus clipping of intracranial aneurysms.

Purpose: To evaluate high cortical signal intensity and chronologic changes for diffusion-weighted MR imaging (DWI) in sporadic Creutzfeldt-Jakob disease. Materials and Methods: We retrospectively analyzed the DWI results of 16 patients with probable CJD (according to WHO criteria) and evaluated the distribution, extent and bilaterality of the lesions in the cortex, basal ganglia and thalamus. We also reviewed the chronologic changes of the lesions by evaluating the followup MR examination results in 8 of 16 patients. Results: Cortical abnormalities were present in 15 (94%) of 16 patients. Isolated cortical involvement was present in 6 patients (40%), while the combined involvement of the cortex and basal ganglia was present in 9 patients (60%). The distribution of the lesions was bilateral in 12 patients and predominantly on the right side in 8 patients. Upon follow-up MR imaging, the cortical lesions showed progress in terms of extent and signal intensity. Basal ganglia abnormalities were present in 9 of 15 patients. Moreover, 4 of 6 patients who had no abnormal signal intensity in the basal ganglia on the initial MR imaging results, showed abnormally high signal intensity upon follow-up MR imaging. Conclusion: The characteristically high cortical signal intensities on DWI in an elderly patient with rapidly progressive dementia should point to the diagnosis of early phase CJD and might be useful for the differential diagnosis.

We report the case of a 16-year-old boy with a solid pancreatic mass which proved to be a nonfunctioning, malignant pancreatic neuroendocrine tumor (PNET). In pediatric patients, malignant pancreatic tumors are rare, especially malignant PNET. When dynamic contrast enhanced MRI showed a well enhancing solid pancreatic tumor on arterial and delayed phases and combined with malignant features, such as vascular invasion, invasion of adjascent organs, and lymphadenopathy, we should include malignant pancreatic neuroendocrine tumor in the differential diagnosis of childhood pancreatic tumors.

Granular cell tumors (GCTs) are uncommon benign neurogenic tumors that can be found at any site in the body including the tongue, skin, subcutaneous tissue, breast, gastrointestinal, and urogenital systems. We report here the CT and ultrasonographic findings of a case of granular cell tumor that occurred in the abdominal wall of a 44-year-old woman.

Ganglion cell tumors of the central nervous system (CNS) are uncommon. There have been few reports in the literature about ganglion cell tumors that arise from the spinal cord, pineal gland, cerebral hemisphere or cerebellum. We recently experienced a case of ganglioneuroblastoma that developed from the hypothalamus in 4-year-old boy. To the best of our knowledge, this is the first reported case of ganglioneuroblastoma in the hypothalamus. We report on this case and we present the neuroimaging and pathologic findings.

Most cerebral sparganosis lesions are located in the white matter of the cerebral hemisphere. A few cases of cerebral sparganosis where the sparganum have migrated into the contralateral cerebral hemisphere have been reported. We report a case of cerebral sparganosis where the sparganum migrated from the white matter of the left frontal lobe to the ipsilateral cerebellar hemisphere after failure of surgical removal of the worm.

Choriocarcinoma is one of the most common malignancies associated with pregnancy. The characteristics of this malignancy include abnormal growth of the trophoblastic tissue, direct invasion of adjacent organs, and distant metastasis; however, it rarely presents extragonadally. Recently, we have experienced a case of primary hepatic choriocarcinoma in a middle-aged-man, which was characterized by a solitary large hepatic mass with central necrosis and hemorrhaging, as well as metastases to the lung and lymph nodes along the hepatoduodenal ligament. We report this case with a review of the literature.

Profound hypoglycemia results in significant brain injury because glucose is essential for normal brain functioning. We present here a case of transient neonatal hypoglycemia with diffuse brain injury. Magnetic resonance imaging was performed 2 days after onset, and this revealed bilateral regions of restricted diffusion in the parietal, occipital, frontal and temporal lobes. On the T1-weighted images, the regions showed indistinct gray matter-white matter differentiation. There were subtle high signal intensity lesions along the corresponding regions of the FLAIR and T2-weighted images.

Kallman syndrome is characterised by hypogonadotrophic hypogonadism and anosmia. T1 weighted MR coronal images show the bilateral absence or hypoplasia of olfactory bulbs, tracts, and sulci. We report the MR findings of Kallmann syndrome and revew the literature.

Spinal cord transection in children may occur following severe trauma such as a motor vehicle accident, and often without evidence of underlying skeletal injury. We report one case which showed cervical cord transection, where no evidence of underlying skeletal injury was seen on MR imaging, four weeks after trauma. When a neurologic defidit is present despite normal routine plain radiographs, further MR imaging is warranted to exclude a cord transection, as demonstrated in our patient.