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Principles of echo shifting with a train of observations was used to perform magnetic susceptibility-weighted magnetic resonance imaging with bolus-tracking in 14 patients with spondylotic myelopathy to assess changes in perfusion parameters of the spinal cord before and after decompression surgery for cervical spondylotic myelopathy. The mean transit time (MTT), bolus arrival time (T0), and time to peak (TTP) were obtained from regions of interest (ROIs) and assessed as the ratio between the spinal cord and the pons (MTT index = MTT(ROI)/MTT(pons), T0 index = T0(ROI)/T0(pons), TTP index = TTP(ROI)/TTP(pons)). The patients were divided into two groups according to percentage improvement on the Neurosurgical Cervical Spine Scale. The MTT index in patients with good recovery (> or =50%) was significantly reduced. The T0 index and TTP index showed no significant change in both groups. Reduction of MTT index may indicate improved perfusion of the spinal cord following surgery for cervical spondylotic myelopathy.

The use of intraoperative angiography to monitor graft patency was retrospectively reviewed in extracranial-intracranial bypass procedures. Forty-two patients underwent 43 extracranial-intracranial bypass procedures with the use of intraoperative angiography. Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass was performed in 41 patients (42 procedures) with ischemic cerebrovascular diseases, and vertebral artery-MCA bypass using radial artery graft for intentional ligation of the common carotid artery in one patient with nasopharyngeal carcinoma. Intraoperative angiography provided high-quality subtraction images in every case. There were no complications due to angiography. Graft occlusion was observed intraoperatively in three cases, but an additional procedure reopened the occluded graft in all three cases. Graft patency rate was 100% after surgery. Outcome was excellent in 40 patients and good in one patient who underwent STA-MCA bypass. Intraoperative angiography provides useful information regarding graft patency during bypass surgery. Intraoperative assessment prior to wound closure allows for the recognition and correction of technical failure and decreases the risk of postoperative complications.

Intraoperative angiography evaluation of the clippings of cerebral aneurysms was investigated in a series of 38 consecutive patients with unruptured cerebral aneurysms to determine any favorable impact on the outcome. Unexpected findings including major arterial occlusion or residual aneurysm were identified. Specific variables such as the size and site of aneurysm were analyzed to determine the impact on clinical outcome and the incidence of clip modification. There were 11 large and 27 small aneurysms in this series. Mortality and permanent morbidity after microsurgical clipping were 0.0% and 2.6%, respectively. Unexpected angiographic findings necessitating clip repositioning consisted of residual aneurysm in two cases and distal branch occlusion or parent vessel stenosis in four. The need for clip modification was significantly higher for large than for small aneurysms (p = 0.007), and the rate of clip adjustment increased with increasing aneurysm size (p = 0.008). Intraoperative assessment prior to wound closure allows for the recognition and correction of defects and decreases the risk of postoperative complications. Intraoperative angiography may become important in the microsurgical clipping of unruptured cerebral aneurysms, especially large aneurysms.

A 39-year-old male presented with a small pontine hemorrhage and subarachnoid hemorrhage. Angiography showed a small left pontine arteriovenous malformation (AVM) associated with a small aneurysm on the pedicle feeding the AVM. The pedicle aneurysm was occluded by microcoils. The AVM was then treated by proton-beam radiosurgery. Follow-up angiography 2 years later revealed that the AVM had disappeared completely without neurological deficit. The combination of embolization and proton-beam radiosurgery was curative in this patient with a pontine AVM associated with an aneurysm on the feeding artery, showing that these techniques can be used to treat inoperable vascular lesions safely.

Hemosiderinuria caused by intravascular hemolysis is a characteristic clinical feature of an acquired hemolytic disorder, paroxysmal nocturnal hemoglobinuria (PNH). We examined the deposition of hemosiderin (iron) in the kidneys of 6 patients with PNH using magnetic resonance imaging (MRI). Three patients with autoimmune hemolytic anemia (AIHA), a hemolytic disorder showing extravascular hemolysis, served as controls. In five of the six patients with PNH, a characteristic T2-weighted MRI of the kidneys, suggesting the deposition of iron (hemosiderin) predominantly in the renal cortex, was obtained. Hemosiderin-deposition was not revealed in the kidneys of any of the patients with AIHA. We conclude that MRI is a sensitive means of detecting hemosiderin deposited in the renal cortex of patients with PNH and that this feature is considerably specific for diseases showing intravascular hemolysis, as represented by PNH.

Synchrotron radiation is a broadspectrum intense X-ray beam. Selected X-ray wavelength was obtained by Bragg reflex. That is a monochromatic beam, which has a high spatial resolution, and has a K-edge discontinuity in attenuation coefficient, which, by energy subtraction, contributes to improve time resolution. An attempt to apply this method to intravenous coronary arteriography was performed in 7 anesthetized dogs. The beam was obtained by synchrotron radiation from accumulation ring, was reflected by silicon crystal, and was detected by 7 inch image intensifier system. Two-dimensional real time images were recorded on video tape. Phantom experiment was also performed. In dogs, coronary arteries were clearly distinguished by synchrotron radiation, especially at real time by video system. Phantom experiment suggested that coronary arteries could be visualized even over the visualized left ventricle. In conclusion, synchrotron radiation using two-dimensional real time images is expected to be useful in intravenous coronary arteriography in man.