Ultrasonography monitoring with Superb Microvascular Imaging during cerebrovascular surgery.

INTRODUCTION: Ultrasonography (US) is used as a real-time dynamic imaging modality during neurosurgery. A novel Doppler US technique, Superb Microvascular Imaging (SMI), can be used to visualize low-velocity flow of small vessels at high resolution with high frame rates. We visualized vessel flow using this US SMI technique and contrast agent during cerebrovascular surgery. METHODS: Forty-three patients with an unruptured cerebral aneurysm (control), ischemic and hemorrhagic moyamoya disease, carotid artery stenosis, hemangioblastoma, severe stenosis of the middle cerebral artery, venous angioma, and intracerebral hemorrhage (ICH) underwent neurosurgery with US SMI monitoring using a contrast agent. The diameter, length, and number of penetrating vessels were analyzed in patients with an unruptured cerebral aneurysm (control), moyamoya disease, and ICH. RESULTS: Diameter and length of cerebral penetrating vessels were significantly increased in patients with moyamoya disease and ICH compared to control patients. The number of penetrating vessels was increased in moyamoya disease patients compared to control and ICH patients. In hemorrhagic moyamoya disease, flow in the penetrating vessels originated from a deep periventricular point and extended to the cerebral surface. Pulsatile cerebral aneurysms during clipping surgery and carotid artery stenosis during carotid endarterectomy were easily identified by SMI. Drastically increased vessel flow in patients with a hemangioblastoma or a venous angioma was observed. CONCLUSION: Using the US SMI technique and contrast agent, we obtained useful flow information of the vascular disease structure and intracerebral deep small vessels during cerebrovascular surgery. Further quantitative analysis will be informative and helpful for cerebrovascular surgery.

Neurosurgical intraoperative ultrasonography using contrast enhanced superb microvascular imaging -vessel density and appearance time of the contrast agent.

BACKGROUND: Ultrasonography (US) provides real-time information on structures within the skull during neurosurgical operations. Superb microvascular imaging (SMI) is the latest imaging technique for detecting very low-velocity flow with minimal motion artifacts, and we have reported on this technique for intraoperative US monitoring. We combined SMI with administration of contrast agent to obtain detailed information during neurosurgical operations. MATERIALS AND METHODS: Twenty patients diagnosed with brain tumor (10 meningiomas, 5 glioblastomas, 2 hemangioblastomas, 1 schwannoma, 1 malignant lymphoma, 1 brain abscess) underwent neurosurgery under US with SMI and contrast agent techniques. Vessel density and appearance time following contrast administration were analyzed. RESULTS: Flow in numerous vessels was not visualized by SMI alone, but appeared following injection of contrast agent in all cases. Flow in tumors was drastically enhanced by contrast agent in schwannoma, hemangioblastoma and meningioma, compared to normal brain tissue. Flows in the dilated and bent vessels of glioblastoma were also enhanced, although flow in hypoechoic lymphoma remained inconspicuous. The characteristics of tumor vessels were clearly visualized and tumor borders were demonstrated by the difference between tumor flow and brain flow, by the increased tumor vessel density and decreased appearance time of contrast agent compared to normal brain vessels. CONCLUSIONS: The combination of SMI and contrast agent techniques for intraoperative US monitoring could provide innovative flow images of tumor and normal brain. The neurosurgeon obtains information about tumor flow and tumor borderline before tumor resection.

Endoscopic ultrasound imaging with high flow mode for endonasal transsphenoidal pituitary surgery.

Intraoperative ultrasound during transsphenoidal surgery (TSS) for pituitary tumors has been reported. In reports of endonasal ultrasound (US), Doppler US vessel images were informative and effective in endoscopic TSS. We performed endoscopic US imaging with high flow mode, which is a novel technology, to visualize small vessels during endonasal endoscopic TSS. Six patients (five with pituitary adenomas and one with Rathoke's cleft cyst) underwent endoscopic US-assisted TSS. A small endoscopic US probe (Olympus, BF-UC260FW; diameter, 6.9 mm) was inserted transsphenoidally to the sellar floor and into the sella turcica, and endoscopic US monitoring was performed. By rotating the endoscopic US probe, the internal carotid artery, anterior cerebral artery, middle cerebral artery, various small vessels, optic nerve, and residual tumor were clearly visualized on the endoscopic US images. Real-time animated vessel images around the tumor could be generated when needed during TSS. The tumors were removed without leakage of cerebrospinal fluid in the six patients, and their visual acuity was restored. Endoscopic US with high flow mode can visualize not only main cerebral arteries but also intracranial small vessels on B-mode US images. Pituitary tumors were clearly recognized and removed safely and precisely by monitoring the cerebral artery and its small branches as landmarks.

Intralateral and Perilateral Ventricular Arteries on Original Axial Magnetic Resonance Angiography in Adult Moyamoya Disease.

BACKGROUND: Patients with moyamoya disease often develop cerebral infarction and hemorrhage, but the ischemic and hemorrhagic subtypes are difficult to diagnose prior to disease onset. We aimed to differentiate the ischemic and hemorrhagic subtypes of moyamoya disease by analyzing the intralateral and perilateral ventricular arteries on the original axial magnetic resonance angiography (MRA) images. METHODS: We retrospectively analyzed the intralateral and perilateral ventricular arteries on the original axial time-of-flight (TOF)-MRA images of 18 patients with hemorrhagic moyamoya disease, 25 patients with ischemic moyamoya disease, and 22 control patients with unruptured aneurysms. RESULTS: There were significantly more intralateral and perilateral ventricular arteries on the original axial MRA images in the patients with hemorrhagic moyamoya disease (6.3 ± 2.7) than in those with ischemic moyamoya disease (0.8 ± 0.9) and those with unruptured aneurysms (0.4 ± 0.8). CONCLUSION: The intralateral and perilateral ventricular arteries on the original axial TOF-MRA images might suggest the hemorrhagic type of moyamoya disease prior to onset.

Ultrasonographic superb microvascular imaging for emergency surgery of intracerebral hemorrhage.

Ultrasonography (US) has been used as a reliable imaging modality, providing real-time information during neurosurgical operations. One recent innovative US technique, superb microvascular imaging (SMI), visualizes small vessels and flow, which are not detected with standard US with doppler. We apply SMI to intraoperative US monitoring in emergency surgery for intracerebral hemorrhage (ICH). Eleven consecutive patients with ICH underwent endoscopic emergency surgery under US monitoring with SMI. After performing a small craniotomy, US images were obtained using SMI, a fusion technique, and a contrast agent technique, with the probe on the brain surface during surgery. Fusion images were obtained with the probe on the head before craniotomy in some patients. Animated US images with SMI could differentiate hematoma containing no vessels from brain tissue, and flow images using SMI and contrast agent techniques clarified the borderlines. Animated fusion images of intraoperative US and preoperative CT provided information on the extent of hematoma and residual hematoma during emergency surgery. We made various fusion CT images showing intracranial hematoma with US probes and decided on the skin incision line before beginning surgery, as if we were using a neuronavigation system. US with SMI, contrast agent, and fusion techniques provide information on the extent of intracranial hematoma and residual hematoma with no vessels and no flow. Monitoring by US and fusion CT images is useful for ICH surgery as a next-generation neuronavigator.

Clinical significance of the coexistence of carotid artery plaque and white matter disease in patients with symptomatic cerebral infarction.

OBJECTIVES: Symptomatic cerebral infarction (CI) can occur in patients without main cerebral artery stenosis or occlusion. This study investigated the unique features of carotid artery plaque and white matter disease (WMD) in patients with symptomatic CI and transient ischemic attack (TIA) but without stenosis or occlusion of a main cerebral artery. PATIENTS AND METHODS: We studied 647 patients who underwent both carotid ultrasound examination and brain magnetic resonance images. Plaque score (PS), plaque number, maximal plaque intima-media thickness and grades of WMD were examined. Subjects were divided into four groups, the CI group, TIA group, myocardial infarction (MI) group and risk factor (RF) group. Plaque and WMD were analyzed in cerebral ischemia group (CI and TIA), compared to non-cerebral ischemia groups and to a high PS group and a high WMD grade group from the RF group. RESULTS: Both of each value of plaque and grades of WMD in the cerebral ischemia group were significantly higher than those in other groups. Grades of WMD in the cerebral ischemia group were significantly higher than those in the high PS group, although there was no significant difference of the each value of plaque between the two groups. The each value of plaque in the cerebral ischemia group was also significantly higher than those in the high WMD grade group, although there was no significant difference of grade of WMD between the two groups. CONCLUSION: Simultaneous increases in carotid artery plaque and WMD are associated with symptomatic CI, which is not caused by stenosis or occlusion of a main cerebral artery.

Cochlear Nerve Action Potential Monitoring for Preserving Function of an Unseen Cochlear Nerve in Vestibular Schwannoma Surgery.

BACKGROUND: Intraoperative monitoring of cochlear nerve action potential (CNAP) has been used in patients with small vestibular schwannoma (<15 mm) to preserve cochlear nerve function. We performed surgery for a larger vestibular schwannoma under CNAP monitoring with the aim of preserving cochlear nerve function, and compared the data with findings from 10 patients with hemifacial spasm who underwent microvascular decompression surgery. CASE DESCRIPTION: We report the case of a patient with a 26-mm vestibular schwannoma and normal hearing function who underwent neurosurgery under electrophysiological monitoring of the facial and cochlear nerves. Amplitudes of evoked facial muscle responses were maintained at approximately 70% during the operation. The latency of wave V on brainstem auditory evoked potential (BAEP) increased by 0.5 ms, and amplitude was maintained at approximately 70% of the value at the beginning of the operation. Latencies of P1, N1, and P2 on CNAP did not change intraoperatively. These latencies were comparable to those of 10 normal patients with hemifacial spasm. CNAP monitoring proved very useful in confirming the location of the cochlear nerve in the operative field and preserving cochlear nerve function. Both facial nerve function and hearing acuity were completely preserved after tumor removal, and wave V latency on BAEP returned to normal and was maintained in the normal range for at least 2 years. CONCLUSIONS: CNAP monitoring is extremely useful for preserving the function of the unseen cochlear nerve during vestibular schwannoma surgery.

Improvement of neurovascular function and cognitive impairment after STA-MCA anastomosis.

OBJECTIVE: In patients with severe steno-occlusive disease of a main cerebral artery, decreased cerebrovascular reserve (CVR) and cognitive impairment without causative focal lesions on magnetic resonance imaging have been reported. We examined ipsilateral and contralateral CVR and cognition before and after superficial temporal artery-middle cerebral artery (MCA) anastomosis operation in patients with internal carotid artery (ICA) or MCA occlusion. METHODS: In 30 patients with ICA or MCA occlusion, cognitive impairment, and decreased CVR, we examined cognition, CVR, leukoaraiosis grades, and blood data. Data from 15 patients who underwent anastomosis were compared to that in 15 patients who did not undergo anastomosis, and to bilateral data already reported on 65 patients with severe steno-occlusive disease. RESULTS: Cerebral blood flow, CVR, and cognition improved after anastomosis compared to before, and compared to patients without anastomosis; improved values were maintained for 5years. CVR recovered after anastomosis, matching the linear relationship between ipsilateral and contralateral CVR seen in the 65 patients. CONCLUSION: The postoperative improvement in cognition and synchronized recovery on the regression line between CVR of the ipsilateral occlusion and contralateral sides may suggest that the CVR is widespread and nonselectively related to cognitive function.

Ultrasonography Monitoring with Superb Microvascular Imaging Technique in Brain Tumor Surgery.

BACKGROUND: Neuronavigation based on preoperative magnetic resonance imaging has been developed as a useful tool to improve visibility of the surgical site in the operative field. Ultrasonography (US) monitoring has also been used as a reliable imaging technique, providing real-time information during neurosurgical operations. We combined the latest innovative imaging technique for detecting very low-flow components, Superb Microvascular Imaging (SMI), with US monitoring during brain tumor surgery. CASE DESCRIPTION: Fifteen patients diagnosed with brain tumor (8 malignant and 7 benign) underwent neurosurgery with US monitoring using an Aplio 400/500 US system with the new SMI technique (imaging frequency, 10-12 MHz; frame rate, 28-31 Hz). Features of the SMI images in the gray scale mode include 1) visualization of low-velocity flow with minimal motion artifact, 2) high resolution of images, and 3) high frame rates. The tumors, tumor vessels, compressed and shifted healthy vessels, and cistern were clearly visualized on the SMI images in the gray scale mode, detailing the characteristics of healthy brain tissue (vertically penetrating, fine, straight vessels), glioblastoma (rounding, dilating, and bending vessels), low-grade glioma (fine and straight vessels), meningioma (many large and branching vessels), and lymphoma (less vascular, low echoic tumor) and demonstrating the tumor-defined border. We also performed biopsies under US monitoring with SMI. CONCLUSIONS: We combined SMI technique with US monitoring during brain tumor surgery and observed healthy and tumor vessels. Further research is important for the development of a more precise and reliable neurosurgery.

Collateral Flow and White Matter Disease in Patients with Internal Carotid Artery Occlusion.

BACKGROUND: When an internal carotid artery (ICA) occludes, a patient may develop cerebral infarction (CI). We investigated whether CI caused by ICA occlusion (ICAO) is associated with collateral flow through the anterior and posterior communicating arteries (ACoA and PCoA). METHODS: In 100 patients with ICAO, we investigated CI and white matter disease by performing an MRI and the anatomy of the ACoA and PCoA were investigated by performing magnetic resonance angiography. All patients were divided into the symptomatic CI group or the no-CI group. The collateral flow pathway was estimated by the anterior cerebral artery (ACA)-PCoA score and the collateral flow volume after ICAO was estimated by the middle cerebral artery (MCA) flow score, based on how well the MCA was visualized. RESULTS: Of 100 patients with ICAO, the symptomatic CI group included 36 patients. ACA-PCoA score and white matter disease grades were significantly higher in the CI group (indicating poor collateral flow). More than 80% of patients with an ACA-PCoA score of 4 (poor collateral) experienced symptomatic CI. Thirty-one symptomatic CI patients (86%) had an MCA flow score of 1 or 2 (decreased MCA flow). CONCLUSION: The ACA-PCoA score and white matter disease grade may suggest an increased risk of CI following ICAO.

Our method of povidone-iodine ointment and gauze dressings reduced catheter-related infection in serious cases.

In experiment 1, we evaluated our method of catheter care at subclavian vein insertion sites for the control of catheter-related infections in seriously ill neurosurgical patients who needed prolonged catheter placement, compared with an older method. In our method, the insertion site was prepared with 10% povidone-iodine solution, followed by application of 10% povidone-iodine ointment, and covered with sterile gauze and a transparent polyurethane dressing. The older method was based on 1996 guidelines for the prevention of intravascular device-related infections. Catheter colonization and mortality were both found to be significantly reduced with our method (p = 0.0214, p = 0.0379, respectively). In experiment 2, we evaluated whether a regimen of catheter care with 10% povidone-iodine ointment was more effective than that without povidone-iodine ointment for the prevention of infections. This suggested effectiveness of 10% povidone-iodine ointment for reduction of infection. Our method of catheter care was useful even in seriously ill neurosurgical patients.

Povidone-iodine ointment and gauze dressings associated with reduced catheter-related infection in seriously ill neurosurgical patients.

Povidone-iodine ointment and gauze covered by transparent dressings were compared with transparent dressings alone in historical controls (both changed twice weekly) in neurosurgical patients needing catheter placement for prolonged periods. Colonization and bloodstream infection were both reduced with the new method (P < .01 and P = .062, respectively).

Spontaneous resolution of nontraumatic bilateral intracranial vertebral artery dissections.

A 49-year-old man presented with nontraumatic bilateral intracranial vertebral artery dissections without subarachnoid hemorrhage manifesting as Wallenberg's syndrome on the right. Magnetic resonance imaging revealed an infarct in the right dorsolateral aspect of the medulla oblongata. Antiplatelet therapy was administered. Vertebral angiography performed on the 9th hospital day (Day 9) revealed pearl and string sign in the right vertebral artery and narrowing of the left vertebral artery. Second angiography performed on Day 25 showed no change, but third angiography performed on Day 74 revealed spontaneous resolution of the bilateral vertebral artery dissections. Magnetic resonance angiography performed on Day 250 showed no evidence of dissection. However, magnetic resonance imaging revealed a small infarct in the splenium of the corpus callosum. Spontaneous resolution of stenotic dissections of the bilateral vertebral arteries is extremely unusual. Serial cerebral angiography and magnetic resonance angiography are very important for monitoring the time course of changes in patients with vertebral artery dissections.

Expression of Pit-1 and growth hormone-releasing hormone receptor mRNA in human pituitary adenomas: difference among functioning, silent, and other nonfunctioning adenomas.

We analyzed the expression of Pit-1 and growth hormone-releasing hormone receptor (GHRH-R) mRNA in various types of functioning and nonfunctioning adenomas using a quantitative reverse transcriptase polymerase chain reaction (RT-PCR) method. Among clinically nonfunctioning adenomas, tumors considered as silent adenomas were reclassified on a pathologic basis. Competitive RT-PCR showed that the levels of Pit-1 and GHRH-R mRNA expression in silent somatotroph adenomas and silent prolactinomas were similar to those in the corresponding functioning adenomas. In silent thyrotroph adenomas, both mRNAs showed high levels of expression that were similar to those in functioning and silent somatotroph adenomas. The results suggest that the cause of the silence in these tumors seems to be in the downstream to transcription of Pit-1 gene in the signaling pathway leading to hormone secretion. Competitive RT-PCR assay could distinguish silent adenomas of the Pit-1 group from the other nonfunctioning adenomas in the expression levels of Pit-1 and GHRH-R mRNAs. In the future, precise diagnosis of various adenomas may become possible by assaying transcription factors such as steroidogenic factor-1 and thyrotroph embryonic factor, which are thought to be related to adenohypophyseal cytodifferentiation.

GH and PRL-Producing Pituitary Adenoma with Neuron-Like Differentiation.

A pituitary adenoma with neuron-like differentiation in the sella turcica is reported. Sections of the tumor showed a mixture of adenoma cells, ganglionic cells, and neuropil-like structures by light microscopy. Both pituitary adenoma cells and large cells recognized as ganglionic cells by H&E were strongly immunoreactive for both growth hormone (GH) and prolactin (PRL), which indicated that these large cells had properties similar to those of pituitary adenoma cells. Furthermore, electron microscopy (EM) revealed characteristic low electron-dense secretory granules as well as GH-type large electron-dense secretory granules in adenoma cells, neuropils, and swollen bulbs of neuronal endings, which indicated that these three populations may be of the same origin. Furthermore, we could not find typical cell bodies of ganglionic cells by EM. These results are consistent with a hypothesis that attempts to explain the origin of the neuronal components by the neuronal differentiation of adenoma cells. Thus, the best designation of our tumor may be "pituitary adenoma with neuron-like differentiation."

An Atypical Acidophil Cell Line Tumor Showing Focal Differentiation Toward Both Growth Hormone and Prolactin Cells.

We report a case of giant pituitary adenoma in a child. Computerized tomography (CT) scan revealed a suprasellar extension tumor mass with hydrocephalus. There was no clinical evidence of acromegaly, gigantism, and other hormonal symptoms. Endocrinologic studies showed within normal value of serum growth hormone (GH: 4.2 ng/mL) and slightly increased levels of prolactin (PRL: 78 ng/mL) and other pituitary hormone values were within normal range. On suppression test by bromocryptin, both GH and PRL levels were reduced. Histopathological findings revealed that the tumor consisted of predominantly chromophobic and partly eosinophilic adenoma cells. Immunohistochemical staining detected GH and PRL in a small number of distinctly different adenoma cells, respectively. Nonradioactive in situ hybridization (ISH) also showed GH and PRL mRNA expression in identical immunopositive cells. Electron microscopy (EM) demonstrated adenoma cells with moderate or small numbers of two types of dense granules and without fibrous body which are characteristic of sparsely granulated GH-cell adenomas. The adenoma does not fit into any classification but may be an atypical acidophil cell line tumor showing focal differentiation toward both GH and PRL cells.

Mixed growth hormone cell- prolactin cell pituitary adenoma with acromegaly: α-subunit most growth hormone cells.

A 51 -year-old woman with mixed growth hormone (GH) cell-prolactin (PRL) cell pituitary adenoma is presented. She had clinical signs due to hypersecretion of GH and PRL. Resected tissue was studied immunohistochemically and morphologically. The serial sections revealed that GH and α-subunit were co-localized in most cells, while GH and PRL were localized in different cells.