Effectiveness of intraoperative visual evoked potential in avoiding visual deterioration during endonasal transsphenoidal surgery for pituitary tumors.

Postoperative visual function is a major concern in transsphenoidal surgery (TSS). Although several reports have demonstrated the importance of visual evoked potential (VEP) monitoring during TSS, the usefulness of VEP monitoring have been controversial because of its reproducibility. Efficacy of VEP was analyzed in 20 consecutive cases of patients who underwent endoscopic endonasal TSS surgery. We adapted a high-power light-emitting diode stimulator with electroretinography using venous anesthesia. In addition, we used black shield patch and braided codes to obtain reproducible VEP amplitudes. Stable and reproducible VEP waveforms were obtained in 38 of 39 eyes (97.4%) before surgery. Fifteen eyes had deteriorated VEP amplitude during operation, and nine eyes had improved VEP amplitude at the end of surgery, and six eyes had not improved VEP amplitude. But no postoperative visual impairment was observed in all cases by temporary halting the surgical manipulation when the VEP was deteriorated. In conclusion, VEP monitoring could be a warning sign to avoid postoperative visual dysfunction. We recommend VEP as a routine monitoring in TSS.

Effects of Hemosiderosis on Epilepsy Following Subarachnoid Hemorrhage.

Epilepsy after aneurysmal subarachnoid hemorrhage (post-SAH epilepsy) is a critical complication that influences clinical and social prognoses. However, the underlying mechanisms remain unclear. We investigated the relationship between hemosiderosis and the incidence of post-SAH epilepsy. About 50 patients with aneurysmal SAH who were admitted to Sapporo Medical University and Oji General Hospital between April 2010 and June 2016 were enrolled in this retrospective study. Hemosiderosis detected by T2*-weighted magnetic resonance imaging(MRI) and the incidence of post-SAH epilepsy were retrospectively analyzed. Post-SAH epilepsy was defined as an unprovoked seizures occurring more than 1 week after the onset of SAH. Six patients (12%) developed post-SAH epilepsy. In all patients, hemosiderosis in the cortex or cerebral parenchyma was detected by T2*-weighted MRI. Statistical analyses revealed that hemosiderosis and the co-existence of intracerebral hemorrhage (ICH) related with post-SAH epilepsy (Fisher's exact test, univariate exact logistic regression analysis: P < 0.05). Post-SAH epilepsy was predicted by hemosiderosis and the co-existence of ICH. The present results suggest that hemosiderin is the principal cause of post-SAH epilepsy and may be a predictor of this critical complication.

Interdisciplinary Prevention and Management of Wound-Related Complications in Extracranial-to-Intracranial Bypass Surgery.

Extracranial-to-intracranial (EC-IC) bypass surgery may be necessary in patients with moyamoya disease and other ischemic conditions. However, there is a potential risk of wound-related complications in some cases. In this study, we report our approach to the prevention of wound-related complications in EC-IC bypass. Technical considerations and pitfalls of surgery are also discussed. This study included 89 patients with ischemic-onset moyamoya disease and atherosclerotic disease who underwent 108 superficial temporal artery (STA)-to-middle cerebral artery bypass procedures. Our study emphasized 3 major features. First, 3-dimensional simulation imaging was used to confirm STA anatomy. Second, the STA was meticulously dissected on the epigaleal layer to protect the galeal layer. Third, scalp skin ischemia was taken into consideration at each step until skin closure. There was no neurologic morbidity or mortality in this series. There were 2 cases of major wound-related complications requiring plastic surgical intervention, and 4 cases of minor complications that were treated conservatively. In major complication cases, the scalp defect was treated with pedicle flap reconstruction. In EC-IC bypass surgery, interdisciplinary management involving neurosurgery, plastic surgery, and radiology should reduce wound-related complications and achieve safe surgery.

Dural arteriovenous fistula at the anterior clinoid process draining directly into the superficial middle cerebral vein.

A 76-year-old man presented with subarachnoid hemorrhage. Selective angiography revealed a dural arteriovenous fistula (DAVF) at the right anterior clinoid process, draining into the superficial middle cerebral vein in a retrograde fashion. Two internal carotid artery aneurysms were also demonstrated at the origin of the posterior communicating artery and the anterior choroidal artery on the same side. The patient underwent craniotomy, and all lesions were treated simultaneously. Rupture of the anterior choroidal artery aneurysm was confirmed. DAVF draining directly into the superficial middle cerebral vein is extremely rare. The precise location of the shunt, the anatomical features, and venous drainage must be evaluated to consider treatment.

The number of microbleeds on gradient T2*-weighted magnetic resonance image at the onset of intracerebral hemorrhage.

OBJECTIVE: Deep intracerebral hematoma (ICH) is frequently associated with microbleed (MB) arising from degenerated MB. Increased numbers of MB are correlated with increased age, and we examined a possible relationship between MB number and ICH onset in younger patients. METHODS: Excluding patients with ICH and a history of ICH, we examined the number of MB and other risk factors in 195 patients with deep ICH (97 male, 98 female) consecutively admitted to our hospital. The patients were equally divided into 3 subgroups according to age (groups A, B, and C). Odds ratios were estimated from logistic regression analyses. RESULTS: The number (percentage) of MB in group A (< or =60 years old, n = 64) 5.0 +/- 9.6 (65.6%) was less than group B (61-69 years old, n = 63) 6.6 +/- 9.1 (79.4%) or group C (> or =70 years old, n = 68) 6.0 +/- 7.0 (86.8%). Multivariate analyses demonstrated that MB greater than or equal to 3 was significantly associated with higher age in group A versus B (odds ratio: 2.3; 95% confidence interval: 1.01-5.3; P = .046) and in group A versus C (odds ratio: 2.6; 95% confidence interval: 1.1-6.2; P =.030). CONCLUSIONS: Our findings suggest that risk factors for the development of ICH may differ with age, and younger patients with deep ICH have fewer MB.

Dynamics of dot-like hemosiderin spots on T2*-weighted MRIs associated with stroke recurrence.

BACKGROUND AND PURPOSE: Dot-like low-intensity spots (dot-like hemosiderin spots: dotHSs) on gradient echo T2*-weighted (-w) brain magnetic resonance imaging (MRIs) are frequently associated with cerebral small vessel disease (SVD), including deep intracerebral hemorrhages and lacunar infarctions. This study investigated how numbers of newly appeared dotHSs contribute to recurrent SVD. METHODS: We prospectively analyzed numbers of newly appeared dotHSs in 12 patients with prior SVD (8 males, 4 females; mean 67.6 +/- 10.7 years old) readmitted with recurring SVD between October 2001 and March 2003. Numbers of appeared dotHSs per year were counted on T2*-w MRI scans after SVD recurrence and compared to previous MRIs. Seventy-one outpatients (35 males, 36 females; mean 64.3 +/- 9.6 years old) with histories of intracerebral hemorrhages (ICH) that came to the hospital during the study period served as controls. The hazard ratio (HR) for recurrence was estimated from a multivariate logistic regression model, using the number of appeared dotHSs (per year) and other risk factors. RESULTS: Multivariate analyses revealed that an elevated rate of recurrence was found in patients with substantial numbers of appeared dotHSs (>or=5/year) (HR, 7.34; P= 0.0008). We also analyzed factors associated with the numbers of appeared dotHSs. A number of appeared dotHSs (>or=5/year) was significantly and independently associated with the initial number of dotHSs (>or=10) on T2*-w MRIs following the first SVD (HR, 18.6; P= 0.0001). CONCLUSIONS: Though a small sample size limited the power of our analyses, our findings suggest that a number of newly appeared dotHSs may be associated with SVD recurrence.

Hematoma size in deep intracerebral hemorrhage and its correlation with dot-like hemosiderin spots on gradient echo T2*-weighted MRI.

BACKGROUND AND PURPOSE: Dot-like low intensity spots (dot-like hemosiderin spots: dotHSs) on gradient echo T2*-weighted MRI have been histologically diagnosed to represent old cerebral microbleeds associated with microangiopathies. They have also been correlated to the fragility of small vessels and the tendency to bleed. Therefore, a substantial number of dotHSs might be associated with a large-sized, deep intracerebral hematoma (ICH). On the other hand, dotHSs may reflect old microbleeds that did not enlarge to symptomatic size. METHODS: To investigate how dotHSs are related to the size (maximal diameter) of primary deep ICH, we analyzed the diameter and the number of dotHSs in 151 patients with deep ICH not associated with subarachnoid hemorrhage or intraventricular hemorrhage (75 males and 76 females, age ranged from 37 to 90 [65.7 +/- 11.3 years old] who were consecutively admitted to Hakodate Municipal Hospital. The hazard ratio (HR) for a maximal diameter of deep ICH < or =2 cm was estimated, using the number of dotHSs and risk factors for stroke. RESULTS: The number of dotHSs associated with the diameter < or =2 cm was 9.2 +/- 11.5, significantly larger than that with the diameter > or =2 cm (4.7 +/- 7.0, P= .012). Multivariate analysis revealed that a maximal diameter of deep ICH of < or =2 cm was found in patients with dotHS (HR, 3.7; 95% confidence interval [CI], 1.4-10.1; P= .009). CONCLUSION: Though small sample size limited the power of our analyses, these findings suggest that the number of dotHSs may be associated with a small diameter of deep ICH.

Dotlike hemosiderin spots are associated with past hemorrhagic strokes in patients with lacunar infarcts.

BACKGROUND AND PURPOSE: Dotlike hemosiderin spots ongradient-echo T2(*)-weighted magnetic resonance imaging of the brain have been histologically diagnosed as old microbleeds associated with small vessel disease (SVD). The authors hypothesize that the presence of many dotHSs may be correlated with the fragility of small vessels and the recurrence of SVD, including lacunar infarction and deep intracerebral hemorrhage (ICH). METHODS: To investigate how dotHSs are related to past history of SVD, the number of subcortical or deep dotHSs was investigated in 146 patients with lacunar infarctions (95 men, 51 women, age 38 to 90 [66.6+/-9.4] years). They were divided into 2 subgroups according to history of deep ICHs or lacunar infarctions. The odds ratio (OR) for past history was estimated from logistic regression analyses with the number of subcortical or deep dotHSs as well as other factors. RESULTS: Of 146 patients with lacunar infarctions, 11 had past symptomatic ICHs and 19 had past symptomatic lacunar infarctions. An elevated rate of history of ICH was found for lacunar infarction patients with many deep dotHSs (>or=3; OR, 9.1; 95% confidence interval, 1.6-51, P=.015). However, history of lacunar infarction was not significantly associated with the number of subcortical or deep dotHSs. CONCLUSIONS: Our findings suggest that many deep dotHSs on T2(*)-weighted magnetic resonance imaging may be correlated with deep ICH-lacunar infarction type of SVD recurrence but not lacunar infarction-lacunar infarction type.

Dot-like hemosiderin spots on gradient echo T2*-weighted magnetic resonance imaging are associated with past history of small vessel disease in patients with intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Lipohyalinosis is considered an important cause of cerebral small vessel disease (SVD), including hypertensive intracerebral hematoma (ICH) and lacunar infarction. Dot-like low-intensity spots (dot-like hemosiderin spots [dotHSs]) on gradient-echo T2*-weighted (T2*-w) magnetic resonance imaging (MRI) have been histologically diagnosed as old microbleeds associated with microangiopathies (lipohyalinosis, amyloid angiopathy) and located in territories of perforating arteries (deep dotHSs) and subcortical regions (subcortical dotHSs). If dotHSs indicate the severity of lipohyalinosis, larger numbers of deep dotHSs may be associated with past history of SVD. METHODS: The number of dotHSs was investigated in 213 patients with deep ICH (106 men, 107 women, 37 to 94 years old, mean age = 65.8 +/- 11.2 years). Patients were divided into 2 subgroups according to past history of SVD. Odds ratio (OR) for the history was estimated from logistic regression analyses of the number of deep or subcortical dotHSs, as well as other factors. RESULTS: Of 213 patients, 36 had a past history of SVD (symptomatic deep ICH in 18, symptomatic lacunar infarction in 17, and both in 1). An increased rate of history of SVD was found for patients with subcortical dotHSs. The OR per 1 subcortical dotHS was 1.09 (95% confidence internal (CI), 1.03-1.17; P =.005), and per deep dotHS, the OR was 1.07 (95% CI, 1.00-1.13; P =.039). CONCLUSIONS: The findings suggest that deep and subcortical dotHSs on T2*-w MRI may indicate the severity of microangiopathy and may predict recurrence of SVD in patients with deep ICH.

Association between a black band on the inner membrane of a chronic subdural hematoma on T2*-weighted magnetic resonance images and enlargement of the hematoma.

OBJECT: The cause and indication for enlargement of chronic subdural hematomas (CSDHs) have remained unresolved. The authors observed a black band on the inner membrane of a CSDH on T2*-weighted magnetic resonance (MR) images obtained in patients with symptoms. After surgical treatment, the band disappeared. The T2*-weighted sequence of MR imaging is an excellent diagnostic tool for detecting ferromagnetic substances, but it is rarely performed in cases of a CSDH. The authors speculate that the black band may be associated with the development of CSDH. METHODS: To investigate how the black band observed on T2*-weighted MR images contributes to the development of a CSDH, 59 lesions in 50 patients with CSDH (41 men and nine women, mean age 70 +/- 11 years [range 48-93 years]) were investigated prospectively. The incidence of black bands on the first T2*-weighted MR image obtained in patients with symptomatic CSDH was 97% (31 of 32 CSDHs), which was significantly higher than that associated with asymptomatic CSDH (11% [three of 27 CSDHs], p < 0.001). The black bands associated with symptomatic CSDH disappeared soon after surgical treatment in 31 CSDHs and became fainter in another. In two instances the CSDH recurred with reappearance of the band. Twenty-four of 27 asymptomatic CSDHs had no accompanying black band. Follow-up MR images demonstrated a later formation of bands in two of 24 asymptomatic CSDHs that enlarged to symptomatic size. Logistic regression analysis revealed that the heterogeneity and thickness of the CSDH on computerized tomography scans were independently and significantly associated with the black band. CONCLUSIONS: The dynamics of the black band may depend on the enlargement or shrinkage of the CSDH.

Detection of hemosiderin deposition by T2*-weighted MRI after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) is very difficult to diagnose several months after its onset. We thus investigated subarachnoid hemosiderin deposition well after SAH by T2*-weighted MRI, a sensitive method for hemosiderin detection. METHODS: To investigate how hemosiderin deposition as confirmed by T2*-weighted MRI contributes to the determination of prior SAH and how the extent of hemosiderin deposition is associated with a number of clinical factors, we retrospectively analyzed 58 patients >3 months after SAH associated with ruptured aneurysms. We also investigated 209 healthy volunteers as controls. RESULTS: T2*-weighted MRI demonstrated subarachnoid hemosiderin deposition in 72.4% of the SAH patients, whereas no deposition was seen in the healthy volunteer group. The hemosiderin was preferentially deposited in the subarachnoid space near a ruptured aneurysm. Odds ratios (ORs) were estimated from logistic regression analyses correlating hemosiderin deposition with other factors. Age (>or=54 years) (OR, 5.1; 95% CI, 1.03 to 25.0; P=0.046), Fisher grade 3 on initial CT (OR, 8.0; 95% CI, 1.26 to 50.4; P=0.027), and Karnofsky Scale score

Dynamics of dotlike hemosiderin spots associated with intracerebral hemorrhage.

The authors observed dotlike, low-intensity spots in T2*-weighted magnetic resonance imaging (MRI), subsequently diagnosed histologically as previous microbleeds associated with lipofibrohyalinosis, amyloid angiopathy, and small vessel disease. The nature of dotlike hemosiderin spots (dotHSs), however, is still unknown. This case report seeks to demonstrate the dynamics of dotHSs associated with an intracerebral hematoma (ICH). T2*-weighted MRI of a 72-year-old man with a history of hypertension demonstrated 4 dotHSs 24 months after a left putaminal hemorrhage. Follow-up T2*-weighted MRI 40 months after the acute event demonstrated the asymptomatic formation of 3 more dotHSs, even with good control of blood pressure. Fifty months after the stroke, T2*-weighted MRI showed that 2 of the new dotHSs had become fainter, whereas the hemosiderin associated with the ICH scar remained detectable. To the authors' knowledge, this is the first description of dotHS dynamics associated with ICH.

[Dynamic changes in magnetic resonance diffusion-weighted and fluid-attenuated images of cerebral fat embolism: a case report].

Cerebral fat embolism (CFE) is serious complication of a long-bone fracture. We reported magnetic resonance (MR) diffusion-weighted (DWI) and fluid attenuated inversion recovery (FLAIR) images in a patient suffered with CFE. A 26-year-old man with a right femoral bone fracture lapsed into a semicoma eight hours later. Eighteen hours after the depressed consciousness, DWI and FLAIR images on MR imaging showed multiple high-intensity spots in corona radiata, basal ganglia, thalamus, corpus callosum, brain stem and cerebellum. Thereby, he was diagnosed as CFE. These multiple lesions were more detectable on FLAIR images than DWI, particularly in posterior fossa. Eight days after the onset, follow-up DWI, FLAIR, and T 2-weighted MR image (T 2 WI) showed most of the lesions disappeared or shrunk. The resolution of the lesions suggests that most of the lesions were brain edema as a result of the unique pathophysiological condition of CFE. The remained lesions were diagnosed as cerebral infarctions. The consciousness of the patient improved alert. Three months later, follow-up MRI showed almost complete resolution of the abnormal intensities. Follow up DWI and FLAIR images observed in the patient indicated that many small lesions occurs throughout the whole brain without a preferential region, and many of the lesions can subside or attenuate in CFE.

[A case of a ruptured pseudoaneurysm arising from the distal part of the posterior inferior cerebellar artery].

We report a rare case of a pseudoaneurysm arising from the distal part of the posterior inferior cerebellar artery (PICA) and which was associated with intraventricular hemorrhages. A 48-year-old female had sudden onset of severe headache and vomiting, and was admitted in a semicomatous state to our hospital. Initial CT scan showed ventricular hematomas resulting in acute hydrocephalus, but no obvious parenchymal or subarachnoid hemorrhage. Ventricular drainage was carried out. Subsequently, cerebral angiography was performed, but neither, an aneurysm nor other vascular abnormality was detected. 50 days after admission, MRI revealed a homogenous and well-circumscribed hypointense mass (12 mm in diameter) in the right cerebellar tonsil, suggesting the presence of hemosiderin. 60 days after the onset, the second angiography showed an aneurysmal shadow arising from the distal part of the PICA. An aneurysmal clipping was performed via the suboccipital approach. A thrombosed aneurysm was identified in the right tonsil. At the time of the operation, we confirmed that the part of the PICA around the aneurysm was intact with neither branching nor discoloration. Histological examination revealed that elastic fiber was not identified in the aneurysmal wall, and the aneurysm was diagnosed as a pseudoaneurysm. Histories of trauma or infection, which may have induced the cerebral pseudoaneurysm, were not obtained by interview.