Pituitary-Targeted Dynamic Contrast-Enhanced Multisection CT for Detecting MR Imaging-Occult Functional Pituitary Microadenoma.

BACKGROUND AND PURPOSE: Although resection of a tumor by trans-sphenoidal surgery is considered the criterion standard for successful surgical treatment of functional pituitary microadenoma, MR imaging occasionally fails to visualize and identify the tumor and supplementary imaging modalities are necessary. We tested the possibility of dynamic contrast-enhanced multisection CT of the pituitary gland accompanying image reconstruction of contrast agent dynamics to identify the localizations of microadenomas and compared the diagnostic performance with conventional pituitary-targeted MR imaging. MATERIALS AND METHODS: Twenty-eight patients with surgically confirmed functional pituitary microadenomas (including growth hormone-, adrenocorticotropic hormone-, and prolactin-secreting adenomas) who underwent pituitary-targeted dynamic contrast-enhanced multisection CT were retrospectively investigated. We undertook image reconstruction of the dynamics of the contrast agent around the pituitary gland in a voxelwise manner, visualizing any abnormality and enabling qualification of contrast dynamics within the tumor. RESULTS: Fifteen cases were correctly diagnosed by MR imaging, while dynamic contrast-enhanced multisection CT correctly diagnosed 26 cases. The accuracy of localization was markedly better for adrenocorticotropic hormone-secreting microadenomas, increasing from 32% on MR imaging to 85% by dynamic contrast-enhanced multisection CT. Compared with the normal pituitary gland, adrenocorticotropic hormone-secreting adenoma showed the least difference in contrast enhancement of the different functional microadenomas. Images acquired at 45-60 seconds after contrast agent injection showed the largest difference in contrast enhancement between an adenoma and the normal pituitary gland. CONCLUSIONS: Dynamic contrast-enhanced multisection CT combined with image reconstruction of the contrast-enhanced dynamics holds promise in detecting MR imaging-occult pituitary microadenomas.

Incidence of growth and rupture of unruptured intracranial aneurysms followed by serial MRA.

BACKGROUND: The natural history, including growth and rupture, of unruptured intracranial aneurysms (UIAs) remains unknown. Here, we present the results of serial magnetic resonance angiography (MRA) follow-up study in 111 patients with 136 UIAs. METHOD: A total of 111 patients with 136 UIAs were followed annually over the past 12 years, using 1.5-Tesla MRA. Follow-up was ended when UIAs were treated surgically, or the patients died of subarachnoid hemorrhage or other causes. Various factors influencing aneurysm rupture or growth were examined statistically. RESULTS: Aneurysm rupture and growth occurred in six and 13 of the 111 patients, respectively. Annual rupture rate was 1.8 % per year and annual growth rate was 3.9 % per year. Aneurysm size was the sole factor influencing rupture(H.R. 1.214, 95 % CI, 1.078-1.368) and multiplicity was the sole factor influencing aneurysm growth (H.R. 5.174, 95 % CI 1.81-14.80). CONCLUSIONS: Serial MRA study showed that the incidence of UIA growth was twice as high as that of UIA rupture. As four patients showed aneurysm rupture or growth within 1 year, further investigations are necessary to determine the optimum interval of radiological investigation and to identify which UIAs grow or rupture within a short time.

Stimulation of primary motor cortex for intractable deafferentation pain.

To treat intractable deafferentation pains, we prefer stimulation of the primary motor cortex (M1). The methods of stimulation we utilize are electrical stimulation and repetitive transcranial magnetic stimulation (rTMS). In our department, we first attempt rTMS, and if this rTMS is effective, we recommend the patient to undergo procedures for motor cortex stimulation (MCS). A 90% intensity of resting motor threshold setting is used for rTMS treatment. In this study ten trains of 5 Hz rTMS for 10 seconds (50 seconds resting interval) were applied to the M1, S1, pre-motor and supplementary motor areas. Only M1 stimulation was effective for pain reduction in 10 of 20 patients (50%). Twenty-nine MCS procedures were performed by subdural implantation of electrodes, and in the case of hand or face pain, electrodes were implanted within the central sulcus (11 cases), because the main part of M1 is located in the central sulcus in humans. The success rate of MCS was around 63%, and seemed to be higher in cases of pain with spinal cord and peripheral origins, while it was lower in cases of post-stroke pain.

A neuroendoscopic approach to the aqueduct via the fourth ventricle combined with suboccipital craniectomy.

OBJECTIVES: We have tried to approach the aqueduct less invasively with the endoscope in combination with a small suboccipital craniectomy, especially for lesions of the aqueduct close to the fourth ventricle. METHODS: The patient is placed in the prone position and a small suboccipital craniectomy is performed. After elevating the bilateral tonsils with retractors, the sheath of the endoscope is inserted from a small skin incision made on the posterior midline of the neck, far from the craniectomy site. The skin incision for endoscopic insertion is planned on the linear extension connecting the aqueduct and the foramen of Magendi on the craniocervical MRI. A rigid endoscope is inserted through the fourth ventricle to the aqueduct for exploration and surgical manipulation. RESULTS: Two cases with hydrocephalus due to aqueductal stenosis, with gait disturbance were operated. After exploration of the aqueduct via the fourth ventricle, endoscopic aqueductal plasty was performed. The postoperative courses were uneventful. The patients' symptoms disappeared. CONCLUSIONS: This approach can be applied for less invasive endoscopic exploration and surgery around the aqueduct close to the fourth ventricle with a rigid endoscope, without overflexion of the neck, or a large craniectomy, or overretraction of the tonsils, or incision of the inferior vermis.

Intraoperative three-dimensional reconstruction of power Doppler vascular images.

We have developed a simple method for reconstructing a three-dimensional (3D) image in the operating room from sequentially scanned intraoperative two-dimensional (2D) power Doppler images using a personal computer and commercially available software. During three operations, 2 for cerebral aneurysm and 1 for cerebral tumor, intracranial vessel images were digitally transferred to a personal computer by freehand scanning over the dura mater or surface of the brain with a 7.5-MHz linear probe. A series of 2D images were converted to a smaller file, and 3D image was reconstructed with volume-rendering software. It took about 15 minutes to reconstruct of the initial 3D image. In the cases of cerebral aneurysm, the vessels connected to the lesion or running nearby were easily identified on the image. In the tumor case, the anatomical relation between the vascular structures and the tumor was clear. This simple 3D reconstruction method provides spatial information about intracranial vascular structures that is useful in intraoperative surgical planning.

Cerebral aneurysm associated with an anomalous hyperplastic anterior choroidal artery.

An unruptured internal carotid artery (ICA) aneurysm arising at the origin of a hyperplastic anomalous AchoA was identified together with a second unruptured middle cerebral artery aneurysm during angiography performed to investigate a striatal and intraventricular haemorrhage in a 55-years-old woman. The anomalous hyperplastic AchoA supplied the left temporal and occipital lobes, and the aneurysm arose proximal to its origin. The patient underwent clipping of the aneurysms, and intra-operative observation revealed that several perforating branches arose directly from the ICA between the AchoA and the ICA bifurcation.

[Cigarette smoking increases the risk of developing a cerebral aneurysm and of subarachnoid hemorrhage].

Despite recent advances in diagnostic and therapeutic techniques, subarachnoid hemorrhage (SAH) is still a serious condition associated with high mortality and morbidity. There are no effective treatments other than surgical intervention. However, another option for decreasing the occurrence of SAH may be prevention of aneurysms formation and of their rupture by controlling risk factors. Cigarette smoking has been recently shown to be one of the major risk factors for SAH. We investigated whether cigarette smoking increased the risk of developing cerebral aneurysms and of SAH. Degree of smoking was investigated in 182 patients with SAH and in 123 patients with an unruptured cerebral aneurysm incidentally detected during investigation of other diseases. Sixty-nine patients with other diseases who were shown to be free of cerebral aneurysms through MR angiography served as controls. Smoking significantly increased the risk of both aneurysm formation and SAH; The odds ratio for SAH was 2.4, and for unruptured cerebral aneurysm 1.7. Smoking especially increased the occurrence of SAH in women and in youngsters. However, smoking did not influence the occurrence of cerebral vasospasm and multiplicity of aneurysms. These data suggest the importance of avoiding smoking to prevent the occurrence of cerebral aneurysms and of SAH.

Combined transfrontal and endonasal endoscopic surgery of epidural abscess following frontal sinusitis. A case report.

A large epidural abscess secondary to frontal sinusitis in a previously healthy 19-year-old man was successfully treated with a small eyebrow incision using combined transfrontal and endonasal endoscopic technique. The abscess was resolved with concomitant pneumatization of the paranasal sinuses. The present case illustrates the promising use of endoscopy in the merging fields of neurosurgery and otorhinolaryngology.