Magnetic resonance angiography of hypoplastic A1 segment of anterior cerebral artery at 3.0-Tesla in Andhra Pradesh population of India

Evaluation of the Frequency of Migraine and CVA Patients Based on Circle of Willis Morphological Variations in MRA Images

Background

The Circle of Willis (CoW) forms a critical collateral route for the compensation pathway at the basal cistern of the brain. This study aims to determine if migraine headaches and cerebrovascular accidents (CVAs) are associated with the prevalence and patterns of CoW arterial variations seen in the three-dimensional time-of-flight magnetic resonance angiography technique in patients.

Materials and Methods

A cross-sectional study was undertaken by a systemic search of electronic databases in the Imaging Center, Abadan's Taleghani Hospital, Iran, from March 2020 to March 2022. Data on the prevalence of variations in patients who presented for screening for migraine and CVA were extracted and analyzed with Student t-test and the Chi-square method.

Results

Findings show complete CoW has been visible in 20.19% of our patients. The anterior part of the CoW was almost intact in all patients. The posterior part of CoW was mostly bilaterally hypoplastic (31.73%) or bilateral aplastic (29.81%) and in some rare cases unilaterally varied. In migraine patients, CoW was rarely in its classic form (15%) and was varied bilaterally in 72.5% of the cases. In CVA patients, CoW was in its complete vascular structure in 23.08% and bilaterally varied in 46.15% of all cases.

Conclusions

Overall, migraine and CVA are associated with anatomical variations in the posterior portions of the CoW. Further larger prospective trials are needed to determine the true prevalence of CoW variations and their pathological significance.

Operative Strategies for Aplastic Circle of Willis Arteries on CTA in Meningioma Surgery: A Case Report

BACKGROUND AND IMPORTANCE

Meningiomas frequently involve critical neurovascular structures. Preoperative imaging with computed tomography angiography (CTA) can help understand the relationship of tumor with neurovascular structures. Although CTA was useful in preoperative planning and less invasive, we present a unique case in which it mistakenly represents a hypoplastic anterior cerebral artery as aplastic and thus displays poor sensitivity in the Circle of Willis.

CLINICAL PRESENTATION

A 66-year-old woman presented with new onset seizures and MRI demonstrated a sphenoid wing meningioma with tumor involvement of the internal carotid artery and right M1 artery. On preoperative CTA, a right A1 artery was not appreciated. However, a hypoplastic right A1 artery was identified during careful dissection guided by micro-Doppler and found to be encased within the tumor. All arteries were preserved, and a near-total resection was achieved with a small remnant of tumor at the supraclinoid internal carotid artery.

CONCLUSION

Although CTAs can be useful in understanding vascular anatomy and its association with tumors, they are not ideal for providing information about hypoplastic arterial segments. Seemingly aplastic arteries on CTA may very well be present, albeit hypoplastic. While we recognize the usefulness of a less invasive modality of CTA to help guide surgical strategy, we underscore recognizing this potential pitfall and recommend the use of the microvascular Doppler during careful dissection when working within tumor in the location of a seemingly aplastic artery.

Incidence of hypoplastic posterior communicating artery and fetal posterior cerebral artery in Andhra population of India: a retrospective 3-Tesla magnetic resonance angiographic study

The posterior communicating arteries (PCoA) are important component of collateral circulation between the anterior and posterior part of circle of Willis (CW). The hypoplasia or aplasia of PCoA will reflect on prognosis of the neurological diseases. Precise studies of the incidence of hypoplastic PCoA in Andhra Pradesh population of India are hitherto unreported, since the present study was undertaken. Two hundred and thirty one magnetic resonance angiography (MRA) images were analyzed to identify the hypoplasia of PCoA and presence of fetal type of posterior cerebral artery (f-PCA) in patients with different neurological symptoms. All the patients underwent 3.0T MRI exposure. The results were statistically analysed. A total of 63 (27.3%) PCoA hypoplasia and 13 cases with f-PCA (5.6%) cases were identified. The hypoplastic PCoA was noted more in males than females (P<0.05) and right side hypoplasia was common than the left (P<0.04); bilateral hypoplasia of PCoA was seen in 37 cases out of 63 and is significant. The hypoplastic cases of the present study also were associated with variations of anterior cerebral arteries and one case was having vertebral artery hypoplasia. Incidence of PCoA as unilateral or bilateral with other associated anomalies of CW is more prone to develop stroke, migraine and cognitive dysfunction. Knowledge of these variations in the PCoA plays a pivotal role in diagnoses of neurological disorders and in neurovascular surgeries and angiographic point of view.