Left Posterior Cerebral Artery Research Articles

Recovery of orthographic processing after stroke: A longitudinal fMRI study

An intact orthographic processing system is critical for normal reading and spelling. Here we investigate the neural changes associated with impairment and subsequent recovery of the orthographic lexical processing system in an individual with an ischemic left posterior cerebral artery (PCA) stroke. This work describes a longitudinal case study of a patient, whose initials are MMY, with impairments in orthographic lexical processing for reading and spelling at stroke onset, and who recovered these skills within 1 year post stroke. We tested the hypothesis that this acute impairment to reading and spelling would be associated with a selective loss of neural activation in the left fusiform gyrus (FG), and that subsequent recovery would be associated with a gain of neural activation in this region. MMY's case provided a unique opportunity to assess the selectivity of neural changes because she demonstrated a behavioral recovery of naming as well; i.e., if there is neural recovery for reading and spelling, but not naming, then these neural changes are selective to the recovery of orthographic processing. To test our hypothesis, we examined longitudinal behavioral and functional magnetic resonance imaging (fMRI) data of reading, spelling, and visual object naming acquired acutely, 3 weeks, 5 months, and one year post stroke. In confirmation of our hypothesis, the loss and subsequent gain of orthographic lexical processing was associated with up-regulation of neural activation in areas previously associated with orthographic lexical processing: i.e., the left mid-FG and inferior frontal junction (IFJ). Furthermore, these neural changes were found to be selective to orthographic processing, as they were observed for reading and spelling, but not for visual object naming within the left mid-FG. This work shows that left PCA stroke can temporarily and selectively disrupt the orthographic lexical processing system, not only in the posterior region adjacent to the stroke, but also in relatively distant frontal orthographic processing regions.

Anatomical variations of circle of Willis - a cadaveric study

Background: The circle of Willis (CW) is a vascular network formed at the base of skull in the interpeduncular fossa. Its anterior part is formed by the anterior cerebral artery, from either side. Anterior communicating artery connects the right and left anterior cerebral arteries. Posteriorly, the basilar artery divides into right and left posterior cerebral arteries and each join to ipsilateral internal carotid artery through a posterior communicating artery. Anterior communicating artery and posterior communicating arteries are important component of circle of Willis, acts as collateral channel to stabilize blood flow. In the present study, anatomical variations in the circle of Willis were noted.Methods: 75 apparently normal formalin fixed brain specimens were collected from human cadavers. 55 Normal anatomical pattern and 20 variations of circle of Willis were studied. The Circles of Willis arteries were then colored, photographed, numbered and the abnormalities, if any, were noted.Results: Twenty variations were noted. The most common variation observed is in the anterior communicating artery followed by some other variations like the Posterior communicating arteries, Anterior cerebral artery and posterior cerebral artery (PCA) was found in 20 specimens.Conclusions: Knowledge on of variations in the formation of Circle of Willis, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in the neurovascular procedures.

Successful delayed coiling of a ruptured growing distal posterior cerebral artery mycotic aneurysm

Intracranial infectious aneurysm (IIA) is a rare form of cerebrovascular malformation for which obliteration may be undertaken after rupture or non-response to targeted antibiotic therapy. We discuss the case of a 19-year-old man who presented with acute neurologic decline (Glasgow Coma Scale of 8) and endocarditis. CT images demonstrated subarachnoid haemorrhage, hydrocephalus and a mycotic aneurysm on the left posterior cerebral artery. Conservative management was initially decided due to the high risk of stroke and hemianopia. However, it was then escalated to endovascular treatment because of increased size of the aneurysm on surveillance scans.

A Comparative Investigation on the Performance of Different Micro Mixers: Toward Cerebral Microvascular Analysis

In this study, a novel fluidic concept was presented to resemble the cerebral microvascular in four types to assess its complexity by using centrifugal platform. The setup consisted of a microstructured disk with a round mixing chamber rotating on a macroscopic drive unit. The left and right internal carotid arteries (L.ICA and R.ICA) and basilar artery (BA) are two isolated vascular system supplying circle of Willis (CoW). The left and right middle cerebral arteries (L.MCA and R.MCA), left and right anterior cerebral arteries (L.ACA and R.ACA), and finally left and right posterior cerebral arteries (L.PCA and R.PCA) constitute efferent arteries of CoW. In this study, cerebral microvascular was investigated by microfluidics approach. The results revealed that a more complex mixing chamber provides normal pixel percentage distribution with respect to the other ones. The outcomes of this study may have implications not only for perception of the intracranial vascular hemodynamic in healthy circumstance, but also for diagnosing the diseases in the blood circulatory system of the human body.

Symptomatic Neonatal Arterial Ischemic Stroke With Prenatal and Postnatal Neuroimaging.

The authors report a girl born at term via planned cesarean delivery. Three days earlier, an antenatal magnetic resonance imaging study, showing no cerebral lesions in the fetus, was performed. Ten minutes after delivery, signs of progressive respiratory failure developed and the infant was transferred to the intensive care unit. On the next day, a computed tomography (CT) scan showed acute ischemic lesions in the areas of the left middle and posterior cerebral arteries. The exact mechanism of stroke remained unidentified. It is possible that emboli occluded the left middle cerebral artery and left posterior cerebral artery. At the age of 1 year and 4 months, the patient demonstrated a slight right-sided hemiparesis more pronounced in the hand. To our knowledge, there are no prior published case studies reporting a healthy fetal brain, which then undergoes an acute neonatal arterial infarction near or during birth following an elective cesarean delivery.

Study of Variant Posterior Cerebral Circulation and its Clinical Relevance

The cerebral blood flow is divided into an anterior circulation and a posterior circulation connected to each other in the form of a circle called Circle of Willis (CW). It is formed by the unification of the internal carotid (ICA) and vertebrobasilar systems Posteriorly, the basilar artery, formed by the left and right vertebral arteries, branches into a left and right posterior cerebral artery (PCA), forming the posterior circulation. The internal carotid system lies anteriorly and is joined to the posterior circulation by posterior communicating (PCoA) arteries. The internal carotid artery divides into anterior and middle cerebral artery. The two anterior cerebral arteries are joined to each other by an anterior communicating artery. The posterior cerebral artery before it joins the posterior communicating artery that means its proximal part is named as the pre communicating part (P1) and the distal part as the post communicating part (P2). In the adult P1 has a diameter larger than the PCoA so that the occipital lobe gets its blood supply mainly via the vertebrobasilar system whereas in the fetus the diameter of the ipsilateral precommunicating (P1) segment of PCA is less than the diameter of PCoA, so that the blood supply to [1] the occipital lobe is mainly via the internal carotid arteries. In some persons, there is a transitional configuration in which the PCoA is equal in diameter to the P1 segment of the PCA. These variations can cause complications if thrombotic material present in atherosclerotic plaques of ICA gets dislodged into PCA through a PCoA which has a larger diameter. In the present study, the configuration of posterior cerebral circulation and its clinical relevance was studied in 40 human brains in the department of anatomy at KJSMC. Adult Type PCA was found in 60% of the specimens studied, Fetal Type PCA was found in 12.5% of the specimens, Transitional Type PCA was found in 25% of the specimens and a combination of Adult and Transitional Type was found in 2.5% of the specimens.

COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF A RARE ANOMALY OF BRACHIOCEPHALIC ARTERIES

After presentation of focal neurologic symptoms due to acute or chronic ischemic brain disease all patients should undergo complex examination in order to identify the source that changed hemodynamics and define management strategy. We present a clinical case of multiple aortic and brachiocephalic arteries anomalies in patient with complaints for dizziness and hearing noise. Computed tomography revealed right aortic arch with anomaly of brachiocephalic vessels branching, hypoplasia of left common carotid artery, agenesis of left internal carotid artery with «adult” type of collateral supply, hypoplasia of left vertebral artery, fusiform aneurysm of left posterior cerebral artery and also right internal carotid artery tortuosity in extracranial segment. Perfusion computer tomography showed symmetric cerebral flow. Computed tomography enables to assess different vascular changes in patients with brachiocephalic arteries anomalies and therefor to optimize treatment strategy.

Duplicate origin and extremely long P1 segment of the posterior cerebral artery diagnosed by MR angiography.

We present what we believe is the first report of a patient with an anomalous artery arising from the distal basilar artery and fusing with the mid-portion of an extremely long P1 segment of the left posterior cerebral artery that was diagnosed on magnetic resonance (MR) angiography. Careful review of MR angiographic images is important to detect rare arterial variations, and partial maximum-intensity-projection images aid their identification on MR angiography.

Study of posterior cerebral artery in human cadaveric brain

Objective. Basilar artery (BA) terminates in right and left posterior cerebral arteries (PCAs). Each PCA supplies respective occipital lobe of the cerebrum. The present study is designed to know the morphology, morphometry, branching pattern, and symmetry of PCA. Methods. The study included 340 PCAs dissected from 170 human cadaveric brains. Results. Morphological variations of P1 segment included, aplasia (2.35%), hypoplasia (5.29%), duplication (2.35%), fenestration (1.17%), and common trunk shared with SCA (1.76%). Morphological variations of origin of P2 segment included direct origin of it from BA (1.17%) and ICA (2.35%). Unusually, two P2 segments, each arising separately from BA and ICA, were observed in 1.17%. Unilateral two P2 segments from CW were found in 0.58%. Morphological variations of course of P2 were duplication (0.58%), fenestration (0.58%), and aneurysm (1.76%). Unilateral P2 either adult or fetal was seen in 4.71%. The group II branching pattern was found to be most common. Asymmetry of P2 was 40%. Morphometry of P2 revealed mean length of 52 mm and mean diameter of 2.7 mm. Conclusion. The present study provides the complete anatomical description of PCA regarding morphology, morphometry, symmetry, and its branching pattern. Awareness of these variations is likely to be useful in cerebrovascular procedures.

Imaging network level language recovery after left PCA stroke.

Purpose: The neural mechanisms that support aphasia recovery are not yet fully understood. Our goal was to evaluate longitudinal changes in naming recovery in participants with posterior cerebral artery (PCA) stroke using a case-by-case analysis.Methods: Using task based and resting state functional magnetic resonance imaging (fMRI) and detailed language testing, we longitudinally studied the recovery of the naming network in four participants with PCA stroke with naming deficits at the acute (0 week), sub acute (3–5 weeks), and chronic time point (5–7 months) post stroke. Behavioral and imaging analyses (task related and resting state functional connectivity) were carried out to elucidate longitudinal changes in naming recovery.Results: Behavioral and imaging analysis revealed that an improvement in naming accuracy from the acute to the chronic stage was reflected by increased connectivity within and between left and right hemisphere “language” regions. One participant who had persistent moderate naming deficit showed weak and decreasing connectivity longitudinally within and between left and right hemisphere language regions.Conclusions: These findings emphasize a network view of aphasia recovery, and show that the degree of inter- and intra- hemispheric balance between the language-specific regions is necessary for optimal recovery of naming, at least in participants with PCA stroke.

Fetal-Type Variants of the Posterior Cerebral Artery and Concurrent Infarction in the Major Arterial Territories of the Cerebral Hemisphere

Fetal-type or fetal posterior cerebral artery (FPCA) is a variant of cerebrovascular anatomy in which the distal posterior cerebral artery (PCA) territory is perfused by a branch of the internal carotid artery (ICA). In the presence of FPCA, thromboembolism in the anterior circulation may result in paradoxical PCA territory infarction with or without concomitant infarction in the territories of the middle (MCA) or the anterior (ACA) cerebral artery. We describe 2 cases of FPCA and concurrent acute infarction in the PCA and ICA territories—right PCA and MCA in Patient 1 and left PCA, MCA, and ACA in Patient 2. Noninvasive angiography detected a left FPCA in both patients. While FPCA was clearly the mechanism of paradoxical infarction in Patient 2, it turned out to be an incidental finding in Patient 1 when evidence of a classic right PCA was uncovered from an old computed tomography scan image. Differences in anatomical details of the FPCA in each patient suggest that the 2 FPCAs are developmentally different. The FPCA of Patient 1 appeared to be an extension of the embryonic left posterior communicating artery (PcomA). Patient 2 had 2 PCAs on the left (PCA duplication), classic bilateral PCAs, and PcomAs, and absent left anterior choroidal artery (AchoA), suggesting developmental AchoA-to-FPCA transformation on the left. These 2 cases underscore the variable anatomy, clinical significance, and embryological origins of FPCA variants.

Hemodynamic Alterations for Various Stent Configurations in Idealized Wide-neck Basilar Tip Aneurysm

Stent-assisted coiling technology is widely used in the treatment of intracranial aneurysms. However, differences among various stent configurations have not been fully characterized. This study investigates the hemodynamic effects for various stent configurations. Computational fluid dynamics simulations were performed on an idealized wide-neck basilar tip aneurysm model, which was constructed from digital subtraction angiography images with a virtual stenting technique. The orifice of the aneurysm was tilted toward the left posterior cerebral artery (PCA). The right half-Y configuration caused only a small change in the overall intra-aneurysmal flow pattern compared with the pattern produced without a stent. Percentage of hemodynamic changes were all compared to the untreated aneurysm. The values of wall shear stress (WSS) and flow velocity showed reductions of 16.36 and 3.22 %, respectively. Although the Y configuration showed relatively obvious decreases of 56.27 and 33.55 % in WSS and flow velocity, respetively, the left half-Y configuration, which is usually deployed as the first stent clinically, produced a more obvious flow reduction than those of the right half-Y and Y configurations. Consistent decreases in the velocity and WSS were observed. WSS and flow velocity showed reductions of 58.39 and 41.76 %, respectively. The cross-bar configuration showed the highest WSS and flow velocity reductions (58.42 and 46.49 %, respectively). The right half-Y configuration had relative more impacts on the WSS of the right PCoA than the left half-Y configuration. For the Y and cross-bar configurations, the WSS of the right PCA obviously decreased. The overall pressure change was less than 1 % for the various configurations, with the Y configuration having the highest pressure increase (0.728 %). Simulation results demonstrate obvious differences among the various stent configurations in a wide-neck basilar tip aneurysm.

Combined Microneurosurgical and Endovascular Management of Grade V Occipital Arteriovenous Malformation: Sequential Delayed Embolization Holds the Key!

A 26-year-old previously healthy woman presented with complaints of sudden-onset headache, decreased level of consciousness, right hemiparesis, and hemianopia. Computed tomography (CT) of the head showed a leftsided parietal hematoma (►Fig. 1). CT angiography showed a complex arteriovenous malformation (AVM) with a venous varix in the center of the hematoma. Cerebral angiogram revealed a grade V AVM in the left parieto-occipital region measuring 6 4 cm and supplied by left posterior cerebral artery (PCA) and middle cerebral artery (MCA) and draining into superior sagittal sinus (SSS) and straight sinus via internal occipital vein/vein of Galen (►Fig. 2). Elective sequential endovascular embolization of the nidus was planned over 3 months in four settings. The aim of partial embolization over weeks was to occlude deep feeders and reduce the nidus to allow definitive treatment, either surgical resection or radiosurgery. Gradual flow reduction should also help prevent normal perfusion pressure breakthrough (NPPB) that might happen due to sudden hemodynamic changes during rapid occlusion of large, highflow AVMs. The treatment plan was developed in a way that each embolization would occlude less than 40% of the arterial feeders and nidus penetration would be limited. MCA feeders were embolized first, followed by the PCA feeders. Onyx (Covidien; Irvine, California, United States) was used in all sessions. It is composed of EVOH (ethylene vinyl alcohol) copolymer dissolved in DMSO (dimethyl sulfoxide), and suspended micronized tantalum powder to provide contrast for visualization under fluoroscopy. Standard technique was used with Apollo catheters with Mirage guidewires (Covidien; Irvine, California, United States) and Onyx 18 and 34 was injected into the nidus. The choice between 18 and 34 was based on flow characteristics observed during the superselective angiograms. At the end of last session of embolization, only small superficial cortical MCA and PCA feeders were left patent (►Fig. 3). The little flow lead to the decision to surgically excise the nidus. The patient underwent left-sided occipital craniotomy and excision of the nidus without complications (►Fig. 4). Postoperative angiogram showed complete resection (►Fig. 5).

The Posterior Limb of the Internal Capsule as the Subcortical Transitional Zone of the Anterior and Posterior Circulations: Insights from Human 7T MRI

Background: In patients with cerebral infarction, identifying the distribution of infarction and the relevant artery is essential for ascertaining the underlying vascular pathophysiological mechanisms and preventing subsequent stroke. However, visualization of the basal perforating arteries (BPAs) has had limited success, and simultaneous viewing of background anatomical structures has only rarely been attempted in living human brains. Our study aimed at identifying the BPAs with 7T MRI and evaluating their distribution in the subcortical structures, thereby showing the clinical significance of the technique. Methods: Twenty healthy subjects and 1 patient with cerebral infarction involving the posterior limb of the internal capsule (ICpost) and thalamus underwent 3-dimensional fast spoiled gradient-echo sequence as time-of-flight magnetic resonance angiography (MRA) at 7T with a submillimeter resolution. The MRA was modified to detect inflow signals from BPAs, while preserving the background anatomical signals. BPA stems and branches in the subcortical structures and their origins were identified on images, using partial maximum intensity projection in 3 dimensions. Results: A branch of the left posterior cerebral artery (PCA) in the patient ran through both the infarcted thalamus and ICpost and was clearly the relevant artery. In 40 intact hemispheres in healthy subjects, 571 stems and 1,421 branches of BPAs were detected in the subcortical structures. No significant differences in the numbers of stems and branches were observed between the intact hemispheres. The numbers deviated even less across subjects. The distribution analysis showed that the subcortical structures of the telencephalon, such as the caudate nucleus, anterior limb of the internal capsule, and lenticular nucleus, were predominantly supplied by BPAs from the anterior circulation. In contrast, the thalamus, belonging to the diencephalon, was mostly fed by BPAs from the posterior circulation. However, compared with other subcortical structures, the ICpost, which marks the anatomical boundary between the telencephalon and the diencephalon, was supplied by BPAs with significantly more diverse origins. These BPAs originated from the internal carotid artery (23.1%), middle cerebral artery (38.5%), PCA (17.3%), and the posterior communicating artery (21.1%). Conclusions: The modified MRI method allowed the detection of the relevant BPA within the infarcted area in the stroke survivor as well as the BPAs in the subcortical structures of living human brains. Based on in vivo BPA distribution analyses, the ICpost is the transitional zone of the anterior and posterior cerebral circulations.

Abstract TP93: Early Morphological Changes in Cerebral Arteries of Cerebral Aneurysm Rupture Model Rats

Introduction: To study the pathomechanisms of cerebral aneurysms, we developed a rat model of cerebral aneurysm rupture. In order, the ruptured aneurysms were located at the P1 segment of the left posterior cerebral artery, on the anterior cerebral artery (ACA), the right internal carotid artery (ICA), the right middle cerebral artery (MCA), and the anterior communicating artery (AcomA). We investigated the early morphological changes in these arteries that preceded aneurysm formation. Methods: We subjected 10-week-old Sprague-Dawley rats to bilateral ovariectomy and modified carotid artery ligation. They were fed a high salt diet. Two weeks later, the bilateral posterior renal arteries were ligated. Vascular corrosion casts were created 2 weeks after renal artery ligation (n=11) and the morphological features were compared on casts from these- and sham rats (n=3) using a scanning electron microscope. Results: The diameter of the left- was larger than of the right P1 in all rats with hypertension and estrogen deficiency. Endothelial changes were predominantly seen in the AcomA and the left P1. In 5 rats we observed small protrusions without loss of endothelial imprints suggesting local loss of internal elastic lamina in the left P1 where ruptured aneurysms were frequently formed. No aneurysms formed at the right ACA-olfactory artery (OA) bifurcation within 2 weeks after aneurysm induction. None of these changes were found in the controls. As ACA-OA aneurysms were frequently seen at 3 months but never ruptured, the pathophysiology of such, and of aneurysms formed at other sites may be different. Conclusion: We first demonstrate the initial morphological changes that occurred as early as two weeks after aneurysm induction in rats. Early intervention for hypertension and endothelial damage may be beneficial in the management of cerebral aneurysms.

Progressive Deconstruction of a Distal Posterior Cerebral Artery Aneurysm Using Competitive Flow Diversion.

Progressive deconstruction is an endovascular technique for aneurysm treatment that utilizes flow diverting stents to promote progressive thrombosis by diverting blood flow away from the aneurysm's parent vessel. While the aneurysm thromboses, collateral blood vessels develop over time to avoid infarction that can often accompany acute parent vessel occlusion. We report a 37-year-old woman with a left distal posterior cerebral artery aneurysm that was successfully treated with this strategy. The concept and rationale of progressive deconstruction are discussed in detail.

Abstract 18462: Hickam's Dictum Revisited: A Multifactorial Etiology of Stroke in a Patient With Rheumatic Mitral Stenosis and Atrial Septal Aneurysm

A 64-year-old gentleman with rheumatic mitral stenosis (MS), coronary artery disease, and active tobacco abuse was admitted with a left posterior cerebral artery (PCA) territory ischemic cerebrovascular accident (CVA). He presented with confusion, headaches, and alexia with stable vital signs. He denied rest or exertional dyspnea. Physical exam revealed right homonymous hemianopia, mild right upper extremity dysmetria, decreased right facial sensation, and mild prosopagnosia. Initial neuroimaging confirmed an evolving left hemispheric infarct. Laboratory testing showed unremarkable inflammatory markers. Computed tomographic (CTA) and magnetic resonance angiography (MRA) of the head and neck confirmed left PCA territory acute or subacute infarction with occlusion of the left P2 segment. 12-lead electrocardiogram demonstrated normal sinus rhythm. Occult atrial fibrillation was not seen. Transthoracic echocardiogram (TTE) showed no evidence of right-to-left interatrial shunt. Moderate left atrial (LA) dilation, posterior mitral leaflet tip calcification, and a resting mean mitral gradient of 20 millimeters of mercury (mmHg) suggested severe mitral stenosis. Given the discrepancy between the patient’s symptoms and the TTE findings, transesophageal echocardiogram (TEE) was performed (Figure). The patient’s left PCA territory infarct was ascribed to multifactorial cardioembolic etiologies: 1) Atrial septal aneurysm (ASA) 2) Rheumatic MS and 3) Aortic arch atheroma. Anticoagulation was recommended and initiated 14 days after his CVA to minimize risk of hemorrhagic transformation. High-dose atorvastatin and aspirin were instituted. He progressed well through rehabilitation, demonstrating steady neurological improvement. The case underscores the importance of pursuing further investigation when discrepancies exist between clinical and objective data. ASA is an uncommon but under-recognized risk factor for cardioembolic stroke.

Geometrical characteristics after Y-stenting of the basilar bifurcation.

We aimed to investigate the angular changes after Y-stenting of the basilar bifurcation aneurysms. A total of 19 patients (age range, 27-80 years; mean age, 52.5 years) underwent Y-stent coiling for basilar bifurcation aneurysm. Three vascular angles (α, β1, β2) were measured in the anteroposterior plane. β1 and β2 represented the angles between the basilar artery and the proximal P1 segments of the right and left posterior cerebral arteries, respectively. α represented the complementary angle between the β1 and β2 angles. Angles were measured before and after stent deployment. Diameters of the basilar artery and P2 segment of the posterior cerebral artery were measured at both sides. Correlation between vascular diameter and angular change of the basilar bifurcation was investigated. Statistically significant α, β1, and β2 angle changes were found after stent deployment (P < 0.001). There was no statistically significant relationship between the diameter of the basilar artery and the α, β1, β2 angle changes (P > 0.05). There was no statistically significant relationship between the diameter of the posterior cerebral artery and the β angle change (P > 0.05). We found a statistically significant inverse correlation between pre-stent β angle and post-stent angle change (right side, P = 0.008; left side, P < 0.001). Y-stenting narrows the effective neck and straightens the vascular bifurcation angle. Most of the angular remodeling occurs on the side that had a more acute angle before stent deployment.

Study of Posterior Cerebral Artery in Human Cadaveric Brain.

Objective. Basilar artery (BA) terminates in right and left posterior cerebral arteries (PCAs). Each PCA supplies respective occipital lobe of the cerebrum. The present study is designed to know the morphology, morphometry, branching pattern, and symmetry of PCA. Methods. The study included 340 PCAs dissected from 170 human cadaveric brains. Results. Morphological variations of P1 segment included, aplasia (2.35%), hypoplasia (5.29%), duplication (2.35%), fenestration (1.17%), and common trunk shared with SCA (1.76%). Morphological variations of origin of P2 segment included direct origin of it from BA (1.17%) and ICA (2.35%). Unusually, two P2 segments, each arising separately from BA and ICA, were observed in 1.17%. Unilateral two P2 segments from CW were found in 0.58%. Morphological variations of course of P2 were duplication (0.58%), fenestration (0.58%), and aneurysm (1.76%). Unilateral P2 either adult or fetal was seen in 4.71%. The group II branching pattern was found to be most common. Asymmetry of P2 was 40%. Morphometry of P2 revealed mean length of 52 mm and mean diameter of 2.7 mm. Conclusion. The present study provides the complete anatomical description of PCA regarding morphology, morphometry, symmetry, and its branching pattern. Awareness of these variations is likely to be useful in cerebrovascular procedures.

Diagnostic TCD for intracranial stenosis in acute stroke patients: experience from a tertiary care stroke center in Karachi, Pakistan.

BackgroundStroke is a common cause of morbidity and mortality around the world. Intracranial large artery atherosclerosis (ICAD) is a frequent etiology of stroke in the South Asian population. There is a need for widely available screening tools to identify patients that are at high risk of stroke due to ICAD for aggressive risk management. This study describes the experience of using the transcranial Doppler (TCD) as a screening tool for this purpose at a tertiary care hospital in a developing country.Methods86 Patients admitted with stroke due to ICAD underwent TCD for six arteries (Right and left middle cerebral arteries, right and left anterior cerebral arteries, right and left posterior cerebral arteries) in addition to the magnetic resonance angiography (MRA) that is done routinely at the stroke center. Arteries were labeled with either <50 or >50% stenosis by TCD using two separate criteria. These findings were compared with those from the MRA which was used as the gold standard. The proportion of patients that had complete exams (all six arteries insonated by TCD) was reported. The success rate of each TCD criteria in detecting arteries with >50% stenosis was also calculated.ResultsThere was an attempt to visualize 516 arteries (86 patients with 6 arteries each) of which 375 (72.7%) were successfully insonated. 38 of the 86 (55.8%) patients had complete examinations. MRA reported 43 (8.3%) arteries as stenosed >50%. The TCD did not categorize any artery as stenosed using either criterion and hence failed to classify any stenosed artery correctly. The positive predictive and sensitivity was 0 for this study and the negative predictive value was 93.3%.ConclusionsThis study indicates the poor sensitivity of TCD to be a reliable screening tool for the presence of ICAD in the South Asian population in a real life clinical setting.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1289-3) contains supplementary material, which is available to authorized users.