S. Kan

Radiological study of symptomatic Rathke's cleft cysts.

We investigated the relationship between radiological findings and the nature of the cyst fluid and histological findings of six Rathkes cleft cysts. The results show that the majority (five of six cases) of symptomatic Rathkes cleft cysts exhibit no enlargement of the sella turcica on plain x-rays, which may be helpful in differentiating cystic pituitary adenoma in the radiological diagnostic process. Three cases with large cysts showing high-intensity T1-weighted magnetic resonance images harbored abundances of cholesterol crystal and hemosiderin pigment in the cyst walls. The high signal intensity in magnetic resonance images of Rathkes cleft cysts may be explained by hemorrhage and a deposition of cholesterol crystal and may be considered in certain cases of Rathkes cleft cyst, especially when they are large.

MR Imaging of IgG4-Related Disease in the Head and Neck and Brain

Autoimmune pancreatitis, sclerosing cholangitis and sialoadenitis, retroperitoneal and mediastinal fibrosis, and insterstitial pneumonia are all IgG-4 related disorders. This short article discusses the head and neck manifestations of this disease: orbital pseudotumor and lacrimal gland, cranial nerve, and pituitary involvement. Intracranially, the dura may be also affected. All of these lesions were contrast-enhancing and T2 dark, findings to be kept in mind so that one can suggest their etiology. SUMMARY: IgG4-related disease is characterized by histologic fibrosis with IgG4-positive plasma cell infiltration. Our study evaluated MR imaging features of IgG4-related disease in the head and neck and brain. Images from 15 patients were retrospectively evaluated for the location, signal intensity, and enhancement patterns of lesions. Lacrimal gland enlargement was observed in 8 cases. Other lesions included orbital pseudotumor in 5, pituitary enlargement in 5, and cranial nerve enlargement in 7; the infraorbital nerve was involved in 4. All lesions were hypointense on T2-weighted images, which is typical for IgG4-related lesions. Multiple sites were involved in the head and neck and brain in 11 patients. The diagnosis of IgG4-related disease should be considered in a patient presenting with T2 hypointense lacrimal gland, pituitary, or cranial nerve enlargement, or a T2 hypointense orbital mass, especially if multiple sites in the head and neck are involved in the presence of elevated serum IgG4.

Rerupture of cerebral aneurysms during angiography – a retrospective study of 13 patients with subarachnoid hemorrhage

SummaryObjective, background. Cerebral angiography, performed within 24 hr of aneurysmal rupture, carries an increased risk of rebleeding. We have investigated the rerupture rate during angiography procedures under deep general anesthesia and the factors that contribute to rebleeding.Methods. We divided 69 patients who had experienced aneurysmal rerupture into 2 groups. Group I (n = 13) suffered rebleeding during cerebral angiography and group II (n = 56) who rebled at a different time. We assessed the effects on rebleeding of the (1) time between the first insult and angiography, (2) WFNS clinical grade on admission, (3) blood pressure during angiography, (4) age and sex, (5) Fisher classification on admission, (6) aneurysmal site, and (7) Glasgow outcome score (GOS).Results. Factors that had a statistically relevant effect on rebleeding during cerebral angiography (Group I) were the performance of angiography within 3 hr of the initial insult, the admission grade, and the aneurysmal site. Especially, the rerupture events during cerebral angiography were concentrated within 3 hr of the initial insult; the rate was 23.9% when angiograms were obtained within 3 hr of onset. Group I patients manifested a worse clinical grade and middle cerebral artery (MCA) aneurysms were prevalent in this group. However, there was no significant difference between the 2 groups with respect to blood pressure, age, sex, Fisher classification, and GOS.Conclusions. Cerebral angiography at ultra-early timing (within 3 hr of the insult) carries a high risk of aneurysmal rerupture, even if the procedure is performed under deep anesthesia and normotensive blood pressure. Cerebral angiography during that period should be avoided.

The effect of encephalo-myo-synangiosis on abnormal collateral vessels in childhood Moyamoya disease

Abstract Child patients with Moyamoya disease initially present with ischemic symptoms. However, the long-term risk of intracranial hemorrhage for childhood Moyamoya disease is unknown. Hemodynamic overload to the fragile collateral vessels has been considered to cause hemorrhage. We reviewed angiograms to evaluate the effect of encephalo-myo-synangiosis (EMS) on abnormally dilated collateral vessels in 13 child patients with Moyamoya disease. EMS was performed on 24 sides in 13 patients ranging from 5 to 14 years of age. Post-operative angiography (6-88 months after surgery) revealed good revascularizations through EMS (larger than one-third of the middle cerebral artery (MCA) distribution) in 18 sides (75%) and smaller revascularizations in 6 sides (25%). In cases with a good revascularization through EMS, reduction of the abnormal collateral vessels was observed not only in the basal Moyamoya vessels (94% of sides) but also in the medullary arteries derived from the choroidal arteries (62% of sides), which are considered to cause intraventricular hemorrhages in adult patients. It is suggested that EMS may reduce the hemodynamic load on dilated collateral vessels and, subsequently, the long-term risk of intracranial hemorrhage in childhood Moyamoya disease. [Neurol Res 2000; 22: 341-346]

Efficacy of the stump pressure ratio as a guide to the safety of permanent occlusion of the internal carotid artery

To determine whether the absolute value for the stump pressure might be a useful index of symmetrical cerebral blood flow (CBF), and to examine correlations with the stump pressure ratio (initial mean stump pressure/preocclusion mean arterial pressure), fifty candidates for ICA injury or permanent occlusion were evaluated preoperatively. Each was continuously monitored for mean stump pressure and arterial pressure before, during (for a total of 20 min), and after balloon test occlusion. During the occlusion, CBF was measured by 99 m Tc-hexamethyl-propyleneamine oxime (99 m Tc-HMPAO) single photon emission computed tomography (SPECT). The stump pressure and the stump pressure ratio were then compared with the results of 99 m Tc-HMPAO SPECT. Patients who failed to tolerate even brief periods of carotid occlusion and showed asymmetric decreases in CBF on SPECT were divided into high and moderate risk groups. Those with no significant changes in CBF on the occluded site formed the minimum risk group. Mean stump pressure was over 50 mmHg in 10 of a total of 25 patients in the high and moderate risk groups, and below 50 mmHg in 5 of the 25 patients in the minimum risk group. The stump pressure ratio did not exceed 56% in any but two patients in the high and moderate risk groups, and values were at least 60% in all patients of the minimum risk group. Decrease of CBF in two moderate risk group cases was localized in the posterior circulation. Difference in symmetrical CBF between the stump pressure ratio vs. the absolute value of mean stump pressure were statistically significant (p < 0.01, Fishers Exact Test). Maintenance of a stump pressure ratio of 60% or more during test occlusion may be a more useful index for a good collateral circulation than any absolute value for mean stump pressure.

Stump pressure as a guide to the safety of permanent occlusion of the internal carotid artery

SummaryDoes the absolute value of the stump pressure (post-occlusion back pressure) become a useful index of a good collateral circulation?The authors continuously monitored the mean arterial pressure before, during and after 20-minute balloon test occlusion in 24 patients. The stump pressure was then compared with the results of99 mTc-hexa-methyl propyleneamine (99 mTc-HMPAO) single photon emission computed tomography (SPECT) performed after 20 minutes of test occlusion.Patients who failed to tolerate even brief periods of carotid occlusion and showed asymmetric decreases in cerebral blood flow (CBF) on SPECT were divided into high and moderate risk groups. Those with no significant change in CBF on the occluded side formed the minimum risk group.Mean stump pressure was over 50 mmHg in three of a total of 13 patients in the high and moderate risk groups, and below 50 mmHg in two of the 11 patients in the minimum risk group. The ratios of the initial mean stump pressure to the pre-occlusion mean arterial pressure (%) and of the final mean stump pressure at the end of occlusion to the post-opening mean arterial pressure (%) did not exceed 58% in any patient in the high and moderate risk groups, and were at least 60% in all patients of the minimum risk group.Maintenance of a mean stump pressure of 60% or more of the mean systemic pressure during test occlusion may be a more useful index of a good collateral circulation than the absolute value of mean stump pressure.

Outcomes analysis of ruptured distal anterior cerebral artery aneurysms treated by endosaccular embolization and surgical clipping.

Although endovascular surgery is now widely used to treat intracranial aneurysms, no comparative studies of clipping versus endovascular surgery to address distal ACA aneurysms at the same institution are available. We compared the results of these treatment modalities to address distal ACA aneurysms at our institution. We treated 68 patients with ruptured distal ACA aneurysms (endovascular surgery, n=13; clipping surgery, n=55). We performed a retrospective comparison of the treatment outcomes. To study the efficacy of endovascular surgery we classified all our cases into three types: type A were small-necked aneurysms, type B were wide-necked aneurysms on the parent artery, and type C were aneurysms in which the A3 portion of the ACA arose from the aneurysmal dome near the neck. Intraoperative hemorrhage occurred in 7.7% of aneurysms treated by endovascular surgery and in 34.5% treated by clipping surgery. In 7.7% of the endovascularly-treated aneurysms we noted coil migration during embolization surgery; venous infarction due to cortical vein injury occurred in 7.3% of clipped aneurysms. Of the endovascularly-treated aneurysms, 7.7% manifested post-embolization hemorrhage; 23.1% manifested coil compaction. In clipping surgery, postoperative rerupture occurred in 1.8% of the aneurysms; one patient presented with postoperative acute epidural hematoma. Clip dislocation was noted in 1.8% of aneurysms. Angiography was indicative of post-treatment vasospasm in 7.7% of aneurysms treated endovascularly and in 50.9% of the clipped aneurysms. The clinical outcome showed no significant difference between endovascular surgery and clipping surgery.

Direct-puncture approach to the extraconal portion of the superior ophthalmic vein for carotid cavernous fistulae

IntroductionThe transvenous approach via the superior ophthalmic vein (SOV) is an available approach for carotid cavernous fistula (CCF), especially in the event that there is no other suitable approach route to the fistula. Surgical exposure of the peripheral roots of the SOV is commonly used; however, often, the SOV is often not accessible because of anatomical problems and/or complications. In this paper, we present and discuss our original direct-puncture approach to the extraconal portion of the SOV.MethodsAn attempt on three patients with traumatic CCF failed with the transarterial approach and the conventional venous approach via the inferior petrosal sinus; therefore, the patients were treated with the direct-puncture approach to the extraconal portion of the SOV using two-dimensional digital subtraction angiography with local anesthesia.ResultsAll cases that had tortuous and partially stenotic division of the SOV were treated successfully with this approach and without complications.ConclusionThis approach will become an alternate approach, especially when the peripheral roots of the SOV are focally narrowed and tortuous, making it impossible to insert a catheter.

The value of long-term clinical follow-up for cases of spontaneous carotid cavernous fistula.

Summary To clarify the value of clinical long-term follow-up with radiological examination, ranging from 12 to 63 months (average: 35 months), 18 consecutive patients suffering from spontaneous carotid cavernous fistula (CCF), were studied prospectively.Five aged patients without aggressive symptoms were treated conservatively, and the other 13 underwent transarterial embolization. The radiological follow-up was primarily by magnetic resonance angiography (MRA), performed from 2 to 6 times (average: 4.1 times) during the follow-up period.In three cases, CCFs persisted, but the other fifteen (83%) demonstrated complete cure as defined by long-term follow-up MRA. The three patients with persistent CCFs were comparatively young, less than 60 years old, had no atherosclerotic factors and demonstrated multiple venous drainage routes with cortical venous drainage on angiography. In two of them, the symptoms completely disappeared, and the other had only mild chemosis. However, surprisingly, in two, MRA revealed residual CCF with drainage into only cortical veins through the sphenoparietal sinus, this radiological finding being well known to signify danger. During the follow-up period, central retinal vein thrombosis occurred in two cases. The common point in these cases was that the superior ophthalmic vein was the only venous drainage route. This is also a point requiring care. We therefore emphasize the importance of careful long-term radiological follow-up for spontaneous CCF patients even when their symptoms improve or disappear. MRA is particularly suitable for this purpose and applicable in the out-patient clinic because of its non-invasive nature.

Subcortical Cerebral Hemorrhage with Reference to Vascular Malformations and Hypertension as Causes of Hemorrhage

The authors have reviewed 80 cases of subcortical cerebral hemorrhage, in all of which intraoperative examinations during craniotomy or autopsies were performed. Cases involving trauma and aneurysm were excluded from the study. The diagnosis of subcortical hemorrhage was made by plain computed tomography in all cases. The most common cause of hemorrhage was vascular malformation (68%; 56 cases), in 20 (36%) of which angiographically occult vascular malformations were noted. Hypertension was present in 23 (29%) of 80 cases but was the cause of hemorrhage in only 9 cases (11%). Hypertension was present in 6 (30%) of 20 angiographically occult vascular malformations, all of which were in patients under 65 years. In 12 (75%) of 16 cases of angiographically occult vascular malformations, prolonged high-dose delayed-contrast computed tomography and magnetic resonance imaging were able to provide definite diagnostic information. We recommend that patients with subcortical cerebral hemorrhage, especially those under age 65, with or without hypertension, be carefully examined by prolonged high-dose delayed contrast computed tomography and magnetic resonance imaging for the presence of angiographically occult vascular malformations causing hemorrhage.