Visualization of Lenticulostriate Arteries on CT Angiography Using Ultra-High-Resolution CT Compared with Conventional-Detector CT.

BACKGROUND AND PURPOSE: The newly developed ultra-high-resolution CT is equipped with a 0.25-mm detector, which has one-half the conventional section thickness, one-half the in-plane detector element width, and one-half the reconstructed pixel width compared with conventional-detector CT. Thus, the ultra-high-resolution CT scanner should provide better image quality for microvasculature than the conventional-detector CT scanners. This study aimed to determine whether ultra-high-resolution CT produces superior-quality images of the lenticulostriate arteries compared with conventional-detector CT. MATERIALS AND METHODS: From February 2017 to June 2017, thirteen patients with aneurysms (4 men, 9 women; mean age, 61.2 years) who underwent head CTA with both ultra-high-resolution CT and conventional-detector CT were enrolled. Two board-certified radiologists determined the number of all lenticulostriate arteries on the CTA coronal images of the MCA M1 segment reconstructed from 512 matrixes on conventional-detector CT and 1024 matrixes on ultra-high-resolution CT. RESULTS: There were statistically more lenticulostriate arteries identified on ultra-high-resolution CT (average, 2.85 ± 0.83; 95% CI, 2.509-3.183) than on conventional-detector CT (average, 2.17 ± 0.76; 95% CI, 1.866-2.480) (P = .009) in 16 of the total 26 MCA M1 segments. CONCLUSIONS: Improvements in lenticulostriate artery visualization were the result of the combined package of the ultra-high-resolution CT scanner plus the ultra-high-resolution scanning protocol, which includes higher radiation doses with lower than the national diagnostic reference levels and stronger adaptive iterative dose-reduction processing. This package for ultra-high-resolution CT is a simple, noninvasive, and easily accessible method to evaluate microvasculature such as the lenticulostriate arteries.

Percutaneous angioplasty and stenting of subclavian arteries before surgical coronary revascularization in a patient with an aberrant right subclavian artery.

An aberrant right subclavian artery occurs in less than 2% of the population. An associated stenosis of the subclavian artery carries a risk of subclavian-coronary steal in patients who undergo coronary revascularization. We report on the case of a 54-year-old man admitted to our hospital for a coronary artery bypass graft (CABG). Angiographic examination revealed bilateral subclavian-artery stenosis with an aberrant right subclavian artery, anomalous origin of the right vertebral artery from the right common carotid artery, and left vertebral-artery occlusion. The patient underwent successful bilateral subclavian angioplasty and stenting.

Augmentation of hepatic glucose uptake by a positive glucose gradient between hepatoportal and central nervous systems.

To determine the role of the glucose gradient between the hepatoportal system (HPS) and the central nervous system (CNS) in regulating hepatic glucose uptake, experiments were conducted with seven conscious dogs using a hepatic venous catheterization technique. With the infusion of somatostatin (0.8 microg x kg(-1) x min(-1)), glucagon (0.65 ng x kg(-1) x min(-1)), and insulin (27 pmol x kg(-1) x min(-1)), arterial glucose levels could be maintained at 8 mmol/l by adjusting the intravenous glucose infusion (G(inf)) according to the following three periods: 1) peripheral glucose infusion period (PE), G(inf) alone; 2) portal glucose infusion period (PO), G(inf) plus constant glucose infusion into the portal vein (GIR(PV), 55.6 micromol x kg(-1) x min(-1)); 3) portal and brain glucose infusion period (PO+CNS), G(inf) and GIR(PV) plus additional glucose infusion into the unilateral carotid and vertebral arteries to abolish the positive glucose gradient between HPS and CNS. Arterial plasma glucose levels were clamped during the three periods (8.1 +/- 0.1, PE; 8.2 +/- 0.1, PO; 8.2 +/- 0.1 mmol/l, PO+CNS). During PO, when a positive glucose gradient was promoted between HPS and CNS, the net hepatic glucose balance (NHGB) determined by the difference between hepatic glucose inflow and outflow was significantly lower than that of PE (-41.5 +/- 5.3, PO vs. -7.5 +/- 3.4 micromol x kg(-1) x min(-1), PE; P < 0.01). However, this decrease in the NHGB significantly increased during PO+CNS, when the glucose gradient between HPS and CNS was minimized, compared with PO (-21.7 +/- 3.2 micromol x kg(-1) x min(-1), P < 0.05). We conclude that a positive glucose gradient between HPS and CNS is an important regulatory factor of hepatic glucose uptake, but other factors also play important roles because minimizing the glucose gradient between HPS and CNS diminished the net hepatic glucose uptake by 50%.

The maze-making and solving technique for coil embolization of large and giant aneurysms.

BACKGROUND AND PURPOSE: Despite major progress in treating aneurysms by coil embolization, the complete occlusion of aneurysms of >10 mm in diameter (large/giant aneurysms) remains challenging. We present a novel endovascular treatment method for large and giant cerebral aneurysms called the "maze-making and solving" technique and compare the short-term follow-up results of this technique with those of conventional coil embolization. MATERIALS AND METHODS: Eight patients (65 ± 11.5 years of age, 7 women) with large/giant unruptured nonthrombosed cerebral aneurysm (mean largest aneurysm dimension, 19 ± 4.4 mm) were treated by the maze-making and solving technique, a combination of the double-catheter technique and various assisted techniques. The coil-packing attenuation, postoperative courses, and recurrence rate of this maze group were compared with 30 previous cases (conventional group, 65.4 ± 13.0 years of age; 22 women; mean largest aneurysm dimension, 13.4 ± 3.8 mm). RESULTS: Four maze group cases were Raymond class 1; and 4 were class 2 as indicated by immediate postsurgical angiography. No perioperative deaths or major strokes occurred. Mean packing attenuation of the maze group was significantly higher than that of the conventional group (37.4 ± 5.9% versus 26.2 ± 5.6%). Follow-up angiography performed at 11.3 ± 5.4 months revealed no recurrence in the maze group compared with 39.2% in the conventional group. CONCLUSIONS: The maze-making and solving technique achieves high coil-packing attenuation for efficient embolization of large and giant cerebral aneurysms with a low risk of recurrence.

Important role of the hepatic vagus nerve in glucose uptake and production by the liver.

We examined the role of the hepatic vagus nerve in hepatic and peripheral glucose metabolism. To assess endogenous glucose production (EGP), hepatic uptake of first-pass glucose infused intraportally (HGU), and the metabolic clearance rate of glucose (MCR), rats were subjected to hepatic vagotomy (HV, n = 7) or sham operation (SH, n = 8), after 10 days, they were then subjected to a euglycemic-hyperinsulinemic clamp together with a portal glucose load in the 24-hour fasting state. Metabolic parameters were determined by the dual-tracer method using stable isotopes. During the experiment, [6,6-2H2]glucose was continuously infused into the peripheral vein. To maintain euglycemia (4.5 mmol/L), insulin (54 pmol x kg(-1) x min(-1)) and glucose were infused peripherally after the 90-minute tracer equilibration and 30-minute basal periods, and glucose containing 5% enriched [U-13C]glucose was infused intraportally (50 micromol x kg(-1) x min(-1)) for 120 minutes (clamp period). EGP was significantly higher in HV rats versus SH rats during the basal period (64.3 +/- 7.6 v 43.6 +/- 5.3 micromol x kg(-1) x min(-1), P < .005)) and was comparable to EGP in SH rats during the clamp period (9.3 +/- 21.5 v 1.1 +/- 11.7 micromol x kg(-1) x min(-1)). HGU was reduced in HV rats compared with SH rats during portal glucose infusion (5.9 +/- 2.4 v 10.1 +/- 3.2 micromol x kg(-1) x min(-1)). The MCR in HV rats was significantly higher than in SH rats in the basal period (11.0 +/- 2.0 v 7.9 +/- 0.8 mL x kg(-1) x min(-1), P < .01)) and was comparable to the MCR in SH rats during the clamp period (41.9 +/- 10.0 and 36.6 +/- 5.7 mL x kg(-1) x min(-1)). We conclude that innervation of the hepatic vagus nerve is important for the regulation of hepatic glucose production in the postabsorptive state and HGU in the postprandial state.

Increased hepatic glucose production and decreased hepatic glucose uptake at the prediabetic phase in the Otsuka Long-Evans Tokushima fatty rat model.

To investigate the time course of the hepatic glucose metabolism in non-insulin-dependent diabetes (NIDDM), we measured hepatic glucose production (HGP) and first-pass uptake of portal glucose infusion by the liver (HGU) using dual-tracer methods in a NIDDM model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats, and in normal controls, Long-Evans Tokushima Otsuka (LETO) rats, at 8, 14, and 28 weeks of age (n = 5, respectively). The fasting plasma glucose level in OLETF rats was significantly higher than in LETO rats at 28 weeks of age (8.9 +/- 1.7 v 6.3 +/- 0.4 mmol/L, P < .01), while there was no significant difference at 8 and 14 weeks. Hyperinsulinemia in OLETF rats appeared at > or = 8 weeks of age. Basal HGP was significantly higher in OLETF than in LETO rats at 8 and 28 weeks (8 weeks, 12.7 +/- 1.7 v 9.4 +/- 1.8 mg x kg(-1) x min(-1), P < .05; 28 weeks, 10.9 +/- 1.6 v 7.1 +/- 1.3 mg x kg(-1) x min(-1), P < .01). At 14 weeks, basal HGP was not significantly different between OLETF and LETO rats. However, at all study points, HGU during a portal glucose infusion was significantly lower in OLETF than in LETO rats (8 weeks, 0.9 +/- 0.2 v 2.3 +/- 0.5, P < .01; 14 weeks, 0.8 +/- 0.3 v 1.4 +/- 0.3, P < .05; 28 weeks, 0.7 +/- 0.2 v 1.4 +/- 0.3 mg x kg(-1) x min(-1), P < .01). Fasting plasma free fatty acid (FFA) levels were not significantly different between OLETF and LETO, except at 8 weeks. Suppression of plasma FFA levels by endogenous insulin during a portal glucose infusion was impaired in OLETF rats compared with LETO rats. In summary, this study demonstrates that derangement of hepatic glucose handling, such as increased basal HGP and decreased HGU, is observed in obese NIDDM model OLETF rats at the prediabetic phase when hyperglycemia is still not apparent. Furthermore, these derangements may be accompanied by impaired lipid metabolism.

Immediately detachable coil for aneurysm treatment.

We developed an endovascular coil that is instantly detached by high-frequency electrical current. By applying the electrical current, a polyvinyl alcohol junction between the coil and the delivery wire is disrupted by heat within a second. This detachment system was shown to be reliable in the treatment of experimental aneurysms.

Characteristics of ethylene vinyl alcohol copolymer (EVAL) mixtures.

PURPOSE: To determine physical characteristics of mixtures of ethylene vinyl alcohol copolymer (EVAL) and metrizamide dissolved in dimethyl sulfoxide, liquid materials developed for embolization of arteriovenous malformations. METHODS: EVAL and dimethyl sulfoxide were mixed in various proportions and sterilized. The viscosity and density of each mixture was measured. Precipitation times were determined by dropping the mixtures into saline or human blood. The mixtures were filtered and the filtrates weighed. RESULTS: Densities and viscosities of the various mixtures differed significantly, proportionally to the concentration of EVAL. Precipitation times also differed significantly, in inverse proportion to the concentration of EVAL. Temperature and aqueous solution did not affect precipitation times significantly. The weight of the filtrate significantly increased with time but was constant for each precipitation time. Temperature significantly affected filtrate weight; aqueous solution did not. CONCLUSIONS: Because of their different physical properties, the various EVAL mixtures are suited to embolizing different types of arteriovenous malformations.

Changes in major phospholipids of mitochondria during postischemic reperfusion in rat brain.

Major mitochondrial phospholipids were examined in rat brain after 30 minutes of reperfusion following 30- or 60-minute periods of ischemia to examine their changes and explore their relationship to mitochondrial dysfunction during postischemic reperfusion. The amount of phospholipids and the percentage of polyunsaturated fatty acid chains, which tended to decrease during 30 minutes of ischemia, recovered after reperfusion. However, after ischemia lasting for 60 minutes, these parameters did not recover but decreased further, suggesting progressive disruption of phospholipids by phospholipase A2 after reperfusion. These changes were particularly notable in cardiolipin, which is contained specifically in mitochondria. The changes were also closely associated with mitochondrial respiration and respiratory enzyme (cytochrome c oxidase and F0F1-adenosine triphosphatase) activities, which have been known to correlate with the amount of cardiolipin. These results suggest that phospholipid metabolism in mitochondrial membranes is an important factor bearing on the integrity of energy metabolism during postischemic reperfusion.

Selection and combination of various endovascular techniques in the treatment of giant aneurysms.

Between April, 1989, and January, 1991, a total of 19 cases of giant aneurysm were treated by the endovascular approach. The patients included seven males and 12 females aged 15 to 72 years. Detachable balloons, occlusion coils, and ethylene vinyl alcohol copolymer liquid were used as embolic materials. In seven cases, thrombosis of the aneurysmal sac and/or base was achieved while sparing the parent arterial flow, complete obliteration of the aneurysm was achieved in four of these. Of these four patients, the thrombotic material was a detachable balloon in two, a combination of a detachable balloon and coils in one, and occlusion liquid in one. In the other three cases, complete occlusion was not achieved; one aneurysm was occluded with a detachable balloon and two with coils. In 11 patients, the parent artery was occluded either by trapping or by proximal arterial occlusion, and all patients showed complete occlusion of the aneurysms. In one patient, a combined bypass procedure and parent artery occlusion was performed. Among the 19 cases in this series there were four transient ischemic attacks, one reversible ischemic neurological deficit, and one death due to aneurysmal rupture during the procedure. Two patients died in the follow-up period, one from pneumonia 2 months postoperatively and the other from acute cardiac failure 2 weeks following surgery. Both deaths were unrelated to the endovascular procedure. It is concluded that the endovascular treatment of giant aneurysms remains difficult because of the large and irregular shape of the aneurysmal base and thrombus in the aneurysmal sac. The proper selection and combination of the available endovascular techniques is therefore of critical importance.

Surgical extirpation of the posterior hippocampal arteriovenous malformation.

BACKGROUND: Surgical extirpation of medial temporal (AVMs) arteriovenous malformations has been one of the most challenging issues in neurosurgery. Yasargil classified mediobasal AVM into four subtypes: amygdala, anterior hippocampal, middle hippocampal, and posterior hippocampal lesions. The lesions around the trigone extending forward to the temporal horn, and medially adjacent to the midbrain, can be referred to as posterior hippocampal AVMs. The therapeutic indications and operative approaches for these lesions remain controversial. METHODS: Nine patients underwent surgical resection for AVMs of the posterior hippocampus using a laterobasal approach. RESULTS: In four patients, AVMs were located chiefly within the lateral ventricle, and the lesions were resected using a laterobasal approach through the occipitotemporal sulcus, or through a hematoma cavity within the fusiform gyrus. Clinical improvement followed the procedure in three of four patients. In the remaining five patients, the nidi were located chiefly within the ambient cistern, extending upward to the basal ganglia. Contralateral hemiparesis occurred in three patients. Two patients showed marked improvement following an initial decline in neurologic status. CONCLUSIONS: A laterobasal transventricular approach is suitable for ventricular AVMs, whereas only limited exposure can be afforded through a transventricular, transchoroidal fissure route for the AVMs within the ambient cistern. For these lesions, a conventional subtemporal approach to the tentorial incisura is preferable.

Delayed thrombus propagation after parent artery clipping for giant fusiform aneurysms of the circle of Willis.

BACKGROUND: Obliteration of a giant fusiform aneurysm without significant therapeutic morbidity is extremely difficult. Ischemic complications have been often reported. METHODS: Two patients with giant fusiform aneurysms of the circle of Willis are presented. Both patients underwent proximal parent artery clipping after a bypass procedure. Balloon occlusion tests confirmed both patients' ability to tolerate flow reduction after proximal clipping. RESULTS: Although both patients awoke from anesthesia without neurologic deficit, they developed contralateral hemiparesis several hours after the operation as a result of a small infarct in the basal ganglia. These ischemic events might be attributed to the delayed thrombosis involving the orifice of the distal perforating arteries. CONCLUSIONS: In the treatment for giant fusiform aneurysms of the circle of Willis, special attention should be paid not only to flow reduction, but also to delayed thrombus propagation that may not be predicted by preoperative balloon occlusion testing.

Congenital subclavian steal syndrome with anomaly of the aortic arch.

A case of congenital subclavian steal syndrome associated with an anomalous right-sided aorta is reported. A 41-year-old man complaining of vertigo and a loss of consciousness was admitted. Physical examination revealed a blood pressure differential between the arms that was 20 mm Hg less in the left. Aortography showed a right aortic arch from which arose the right subclavian and both common carotid arteries. The left subclavian artery did not opacify. Right vertebral angiography showed retrograde filling of the left vertebral. A left carotid-subclavian bypass was performed. Postoperatively, the patient is symptom free with equalized blood pressure.

Endovascular coil embolization of a recurrent giant internal carotid artery aneurysm via the posterior communicating artery after cervical carotid ligation: case report.

The case of a 29-year-old man with a giant fusiform aneurysm of the left internal carotid artery (ICA) is presented. The aneurysm, treated by cervical ICA ligation and extracranial-intracranial bypass, recurred 4 years later owing to recruitment of the posterior communicating artery (PCoA). Because of the previous bypass surgery a direct surgical approach was excluded. After an initial failure with balloon embolization, the aneurysm was embolized successfully with occlusive platinum microcoils through the microcatheter navigated into the aneurysm via the enlarged PCoA. Endovascular coil embolization may be useful in the treatment of cerebral aneurysms not amenable to direct surgery or balloon embolization.

Surgical treatment of pericentral arteriovenous malformation.

Surgical treatment of pericentral arteriovenous malformation (AVM) near the central sulcus is discussed. Thirty-four patients with pericentral AVM were treated and they can be classified into four subtypes: operculofrontal AVM (nine cases); dorsolateral AVM (nine cases); parasagittal AVM (11 cases); and giant AVM involving sensorimotor cortices (five cases). In all surgically treated patients with operculofrontal AVM or dorsolateral AVM, nidi were totally removed and permanent morbidity was 6%. On the other hand, complete obliteration was usually difficult for parasagittal AVMs. Among six patients with surgically-treated parasagittal AVM, transient paralysis was found in three (50%) and permanent morbidity was observed in one (17%). Among four patients with parasagittal AVM who were treated by embolization therapy alone, transient paralysis was found in three (75%) and permanent morbidity was recognized in two cases (50%).

Dolichoectasia of the middle cerebral artery--Case report.

A 59-year-old female with a previous history of head injury presented with mild occipitalgia due to dolichoectasia of the middle cerebral artery (MCA). Initial examination by computed tomography and angiography using the usual projections suggested a terminal internal carotid artery saccular aneurysm. However, angiography by the reverse Waters view excluded a saccular aneurysm. Superselective angiography using a microcatheter revealed the complex tortuous course of the MCA due to dolichoectasia. She was discharged and has remained asymptomatic. Superselective angiography is extremely useful for the diagnosis of dolichoectasia localized in the MCA.

Large and giant middle to lower basilar trunk aneurysms treated by surgical and interventional neuroradiological methods.

Treatment of large and giant aneurysms of the basilar artery remains difficult and controversial. Three large or giant aneurysms of the lower basilar artery were treated with a combination of surgical and interventional neuroradiological procedures. All patients underwent the balloon occlusion test with hypotensive challenge (blood pressure reduced to 70% of the control value). The third patient did not tolerate the test. In the first patient, both vertebral arteries were occluded through a craniotomy. In the second patient, both the aneurysm and the basilar artery were occluded by detached balloons. In the third patient, one vertebral artery was occluded by surgical clipping and the other by detached helical coils and fiber coils. In spite of anti-coagulation and anti-platelet therapy, postoperative thrombotic or embolic ischemia occurred in the second and third patients. Fibrinolytic therapy promptly corrected the ischemic symptoms, but the second patient developed hemorrhagic complications at the craniotomy area 2 hours later. At follow-up examination, the first patient had only 8th cranial nerve paresis, the second patient who had a hemorrhagic complication was bed-ridden, and the third patient had no deficit. Interventional occlusion requires a longer segment of the parent artery compared to surgical occlusion of the parent artery and might cause occlusion of the perforating arteries. However, selected use of various coils can occlude only a short segment of the parent artery. Thus, the postoperative management of thromboembolic ischemia after the occlusion of the parent artery is easier using the interventional technique.

Circulatory arrest with profound hypothermia during the surgical treatment of large internal carotid artery aneurysm--case report.

A 43-year-old male presented with a cerebral aneurysm manifesting as right facial paresthesia, without neurological deficit. Angiography revealed a large aneurysm (22 mm) of the left internal carotid artery. Intravascular treatment using placement of a detachable coil was attempted, but the coil did not stay in the aneurysmal cavity and the procedure was abandoned. The patient did not tolerate the transient balloon occlusion test of the left internal carotid artery. Therefore, the aneurysm was clipped through an open craniotomy with profound hypothermia (20 degrees C) with cardiac arrest (24 minutes). The aneurysmal dome was collapsed, allowing easy dissection of the posterior communicating artery. The closed chest method was used during the extracorporeal cardiopulmonary bypass. Postoperative angiography revealed complete neck clipping with preservation of carotid blood flow. The patient recovered well and resumed his employment. Circulatory arrest with hypothermia provides several benefits for the surgical treatment of large and giant aneurysms.

Usefulness of non-detachable balloons in endovascular treatment for cerebral aneurysms.

An endovascular non-detachable balloon technique was used to treat 14 patients with cerebral aneurysms. Eight patients presented with subarachnoid hemorrhage, and six others presented with headache or mass effect. Six aneurysms were located in the anterior circulation and eight in the posterior circulation. Seven aneurysms were giant, three were large, and four were small. All target aneurysms or vessels were occluded successfully. Parent vessel was successfully spared in seven cases. There were no procedural complications related to the non-detachable nature of the balloon used. Follow-up angiography detected refilling of aneurysms in three of 11 patients, two with small ruptured aneurysms that bled again following partial deflation or balloon movement. The other aneurysms tested remained occluded, as demonstrated on follow-up angiograms, for up to 15 months. Outcomes were good to excellent in 10 patients, poor in one, and three died. Non-detachable balloons might be preferred for treatment of certain types of cerebral aneurysms including those where intraaneurysmal maneuvers might be considered dangerous, for example, with recent bleeding or intraluminal fresh clots; where precise placement of the balloon is required, for example, in the vicinity of perforators or collaterals emerging near the neck; and where detachment could be dangerous or difficult in broad neck and fusiform aneurysms or in tortuous parent vessels.

Improved provocative test for the embolization of arteriovenous malformations--technical note.

A modified provocative test to assess the safety of embolization of cerebral and spinal arteriovenous malformations is described. The modified test uses successive amobarbital and lidocaine injections to elicit any possible neurological deficit, both mixed with radiopaque material to visualize the distribution of the anesthetic in the vessels. The modified provocative test caused no false negative results in 11 patients tested, compared to six of 27 patients with the unmodified method.