Type 2 proatlantal intersegmental artery associated with persistent trigeminal artery diagnosed by MR angiography

Purpose

The type 2 proatlantal intersegmental artery (PIA) is a rare anastomosis between the external carotid artery (ECA) and vertebral artery (VA) that passes through the foramen magnum. The persistent trigeminal artery (TA) is the most common anastomosis between the internal carotid artery (ICA) and basilar artery. The purpose of this paper is to present the first case of a type 2 PIA associated with an ipsilateral persistent TA diagnosed using magnetic resonance (MR) angiography, and we briefly discuss the embryology of this rare anomaly.

Methods

An 83-year-old man with cerebral infarctions underwent cerebral MR imaging, and head and neck MR angiography using a 1.5?T imager. MR angiography was obtained using the standard non-contrast three-dimensional time-of-flight technique.

Results

MR angiography showed aplasia of the proximal left VA and a large anastomotic artery between the left ECA and distal left VA that passed through the foramen magnum, indicative of a type 2 PIA. This patient also had an anastomosis between the precavernous segment of the left ICA and midbasilar artery via a lateral course, indicative of a lateral-type persistent TA.

Conclusion

We present the first case of type 2 PIA associated with ipsilateral lateral-type persistent TA diagnosed by MR angiography. MR angiography should be performed including the carotid bifurcation to find more frequently extracranial arterial variations, including type 2 PIAs.     

Variation of the origin of the left common carotid artery diagnosed by CT angiography

Introduction

The left common carotid artery (LCCA) is usually a second branch of the aortic arch that arises between the brachiocephalic trunk (BCT) and left subclavian artery; relatively frequently, it also arises from or shares a common origin with the BCT. In patients with LCCA of anomalous origin, transfemoral catheterization into the LCCA is sometimes difficult, and transbrachial or transradial approach may be recommended. We evaluated the prevalence of these variations on computed tomography (CT) angiography.

Methods

We retrospectively reviewed CT angiographic images of 2,357 patients obtained using either of two 64-slice multidetector CT scanners. All patients were Japanese and underwent scanning from the aortic arch to the intracranial region; most had or were suspected of having cerebrovascular diseases.

Results

We evaluated CT angiographic images of 2,352 patients after excluding four patients with LCCA occluded at its origin. The LCCA arose from the BCT in 141 patients (6.0 %) and had a common origin with the BCT in 130 patients (5.5 %). We found 11 aberrant right subclavian artery (0.47 %), and four of the 11 patients (36 %) had LCCA of common origin with the right common carotid artery, forming a bicarotid trunk (prevalence: 0.17 %).

Conclusions

The total prevalence of variations of LCCA origin diagnosed by CT angiography was 11.7 %.     

Developmental anomalies of the distal vertebral artery and posterior inferior cerebellar artery: diagnosis by CT angiography and literature review

Purpose

The aim of this study was to identify variations in the anatomy of the distal vertebral artery (VA) and posterior inferior cerebellar artery (PICA) with computed tomography (CT) angiography.

Methods

CT angiography was performed at two hospitals. And the results were analyzed for VA anomalies.

Results

Seven of the 3067 patients who received brain CT angiography in first hospital had seven intracranial VA fenestrations. Twelve of 546 patients who received CT angiography of intracranial and extracranial vessels in second hospital had 16 anatomical variations of the V3 segment. Two fenestrations of the V3 segment, three C1 origins of the PICA, seven aberrant VAs with an intradural course at the C2 level without a normal VA, and four aberrant VAs with an intradural course at the C2 level with a normal VA were observed. Seventeen of the 314 patients who received cervical CT angiography in second hospital had 21 anatomical variations of the VA. Two fenestrations of the V3 segment, six C1 origins of the PICA, three C2 origins of the PICA, one VA origin of the occipital artery, one fenestration of the V4 segment, five aberrant VAs with an intradural course at the C2 level without a normal VA, and three aberrant VAs with an intradural course at the C2 level with a normal VA were observed.

Conclusions

A certain number of anatomical variants of the distal VA and PICA may reflect variations in size and connections of the lateral or posterior spinal artery.

     

Rare saccular aneurysm in a medial type persistent trigeminal artery trunk and literature review

Purpose

We report an extremely rare case of saccular aneurysm in the left medial type persistent trigeminal artery (PTA) trunk and discuss its clinical importance.

Materials and methods

A 77-year-old woman who had symptom suggestive of vertebrobasilar insufficiency underwent cerebral magnetic resonance (MR) imaging and non-contrast three dimensional time-of-flight MR angiography (3D TOF MRA) using a 3 T scanner.

Results

3D TOF MRA images revealed a left medial type PTA originated from the left internal carotid artery C5 portion, through cavernous sinus and connected to the basilar artery with a saccular aneurysm in the mid portion of its trunk. The basilar artery (BA) under the union was hypoplastic. The bilateral posterior communicating arteries were absent.

Conclusion

To our knowledge, this is the first report of a medial type PTA associated with a saccular aneurysm in the PTA trunk. Being aware of this is crucial in clinical, because they can influence surgical and interventional procedures.     

Anatomical variations in branching pattern of arcus aorta: 64-slice CTA appearance

Purpose

To review the 64-slice CTA (computed tomography angiography) appearance of anatomical variations in branching pattern of the arcus aorta, and to determine their prevalence in 1001 cases.

Materials and methods

1001 cases that underwent carotid CTA (performed by a 64-slice scanner) were included in the study.

Results

Seven types of aortic arch were found. In 853 cases (853/1001, 85.2 %) classical branching pattern of arcus aorta (three branches; TB, LCC, LS) was observed. Variations were present in 147 cases (147/1001, 14.7 %). One case (1/1001, 0.1 %) had right aortic arch. The most frequent variation was origination of LCC from TB (arch with 2 branches, TB with LCC and LS) which was observed in 78 cases (78/1001, 7.8 %). Origination of LV directly from the aortic arch (four branches; TB, LCC, LV, LS or TB, LCC, LS, LV) was observed in 51 cases (51/1001, 5.1 %). In two cases (2/1001, 0.2 %) truncus bicaroticus (3 branches; RS, common trunk for carotids, LS) was present. In seven cases (7/1001, 0.7 %) aortic arch had four branches in the order of RCC, RS, LCC and LS. In one case (1/1001, 0.1 %) left truncus brachiocephalicus (three branches; RS, RCC, LTB) was present. Seven cases (7/1001, 0.7 %) had aberrant RS (RCC, LCC, LS, RS).

Conclusion

Variations in branching pattern of arcus aorta are not rare and being aware of them before surgical and interventional procedures of this region is important. CTA can depict the anatomical features of the aortic arch and is valuable as a road map.     

Display with 64-detector MDCT angiography of cerebral vascular variations

Purpose

The aim of this study was to assess the cerebral variations and observe their frequency in the patients who have undergone angiographies with the state of the art 64-slice multidetector computed tomography (MDCT) angiography technique due to various reasons.

Methods

500 patients (253 women, 247 men) who had CT scan in the period of April 2008 to March 2010 at Dicle University Medicine Faculty Hospital Radiology Unit were surveyed in this study. Patients who had CT scan with brain CT angio protocol were evaluated using multiplanar, maximum intensity projection (MIP) and volume rendering (VR) images in work station.

Results

773 variations were totally detected among 500 patients. Variations were categorized as Willis polygon, fenestration and other variations. Frequent variations were detected at Willis polygon and posterior communicating artery (PCOA) hypoplasia was detected as the prevalent variation.

Conclusions

In the present study, we have demonstrated that cerebral vascular variations are frequent and that these variations can be detected in a non-invasive manner using the MDCT angiography. The results obtained from our study may serve as preoperative guidelines for the units performing surgical procedures.     

Persistent dorsal ophthalmic artery and ophthalmic artery arising from the middle meningeal artery diagnosed by MR angiography at 3 T

Introduction

A persistent dorsal ophthalmic artery (OA) is a rare variation that originates from the cavernous segment of the internal carotid artery (ICA) and enters the orbit via the superior orbital fissure (SOF). Occasionally, the OA also arises from the middle meningeal artery (MMA) and enters the orbit via the SOF. These two major variations of the OA have not been well described by magnetic resonance (MR) angiography. We evaluated their prevalence on MR angiography at 3 T.

Methods

We retrospectively reviewed our database of MR angiographic images obtained using a 3 T imager. Of images of 846 patients, we evaluated those of 826 patients (1,652 OAs) with special attention to OA origin and its course into the orbit. We excluded images of the 20 because quality was insufficient to assess.

Results

We found 7 (0.42 %) persistent dorsal OAs among 1,652 OAs (right/left, 6/1; male/female, 3/4). Twenty-four (1.45 %) OAs arose from the MMA (right/left/bilateral, 11/5/4; male/female, 10/10), three of which also demonstrated a small normally branching OA. In one patient, we observed both right persistent dorsal OA and left OA arising from the MMA.

Conclusions

Per OA, the prevalence of persistent dorsal OA was 0.42 % and of OA arising from the MMA, 1.45 %, with a tendency toward right-side predominance. OA arising from the MMA can be seen bilaterally; preprocedural knowledge of this variation is important because of the danger associated with endovascular procedures of the external carotid system when the OA arises from the MMA.     

Variations of renal arteries on 64 slice Multidetector Computed Tomography

Introduction

The incidence of accessory renal arteries is very high. Multidetector Computed Tomography (MDCT) is a minimally invasive alternative to conventional angiography in preoperative evaluation. The aim of this study was to document the incidence of accessory renal arteries and the level of origin of main renal arteries from abdominal aorta.

Analysis of the dynamic relationships between the lingual artery and lingual markers in patients with obstructive sleep apnea

Purpose

To determine the relationships between the lingual artery and the lingual markers in tongue resting and extended positions in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) for the clinical application of functional tongue surgery.

Method

Computed tomography angiography (CTA) of the lingual artery was performed on 30 OSAHS patients using a 16-slice spiral CT scanner. The anatomical relationships between the lingual artery and the lingual markers were analyzed with the tongue in resting and extended positions using the CTA images.

Results

The course of the lingual artery resembled the configuration of the Big Dipper constellation when the tongue was in a resting position. When the tongue was in a full-extended position, the majority of the lingual artery moved forward and upward with the hyoid and formed a “√” fashion. The positions of the tip of the greater horn of the hyoid changed with the tongue positions. While the relationship between the main lingual artery and the tip of the greater horn of the hyoid, as well as the distances between bilateral lingual arteries, remained constant in both tongue positions.

Conclusions

In conditions of dynamic tongue movement, the tip of the great horn of the hyoid and the lingual midline are constant anatomical markers to indicate the course of the lingual artery.     

Duplicate origin and fenestration of the middle cerebral artery on MR angiography

Introduction

Duplicate origin of the middle cerebral artery (MCA) is rare and has been misdiagnosed or confused as fenestration of the proximal M1 segment of the MCA. The condition is not a true fenestration and occurs when two MCA branches arise separately from the terminal segment of the internal carotid artery, and fuse to form an arterial ring. We researched our institutional records to determine the prevalence of such cases and investigated its characteristic features on magnetic resonance (MR) angiography.

Methods

To isolate these cases, we retrospectively reviewed cranial MR angiographic images of 3,491 patients obtained on either of two 1.5-tesla scanners at our institution from April 1, 2007 through December 31, 2009.

Results

We found four cases of duplicate origin of the MCA, two cases each on the right and the left (3 men, one woman), representing a prevalence of 0.11%. All four arterial rings were small and mimicked fenestration of the proximal M1 segment. During the same period, we found three MCA fenestrations, two at the proximal M1 segment and one at the middle M1 segment. Total prevalence of duplicate origin and fenestration was 0.20%.

Conclusions

In our institution, we observed 0.11% prevalence of duplicate origin of the MCA on MR angiography, and all were small and mimicked fenestration. Clinically, an important difference between duplicate origin and fenestration of the MCA is the potential collateral circulation available from the inferior branch in the case of saddle embolism occlusion of only the superior branch when there is duplicate origin of the MCA.     

Persistent primitive olfactory artery: CT angiographic diagnosis and literature review for classification and clinical significance

Objectives

The aim of this study was to investigate the incidence of a persistent primitive olfactory artery (POA) and to review the literatures focusing on the classification and clinical significance of this variant.

Design

To identify cases with persistent POA, we reviewed the records of computed tomography (CT) angiography performed on 3,067 patients in our institution from January 1, 2011 to August 31, 2013. Literatures on the incidence and classification of a persistent POA were reviewed.

Results

Among these patients, eight were diagnosed with a persistent POA (five men, three women, aged 44–82 years), an incidence of 0.26 %. Six persistent POAs terminated as a distal anterior cerebral artery (ACA) and two as a distal middle cerebral artery. Previous studies applied similar definitions for the classification of persistent POA; however, there has been confusion on the definition of variant 2.

Conclusion

In our institution, the incidence of persistent POA seen on CT angiography was 0.26 %. An artery with its embryological course along the olfactory bulb should be classified as a persistent POA and differentiated from dural artery from ACA.     

Visualization of the ophthalmic artery by phase-contrast magnetic resonance angiography: a pilot study

Objective

This study aimed at investigating whether phase-contrast (PC) magnetic resonance (MR) angiography is useful for visualizing the ophthalmic artery (OA).

Methods

This prospective study enrolled 196 consecutive outpatients who underwent three-dimensional PC MR angiography. The basal image parallel to the anteroposterior dimension of the OA was extracted for analysis from the imaging data.

Results

The 99 male and 97 female subjects were aged from 10?years to 80?years (mean 47.9?years). The OAs were supplied only by the external carotid system or in combination with the internal carotid artery (ICA) in 18 subjects (9.2?%). The bilateral OAs were symmetrical in 12?%, asymmetrical in 87?%, and unidentified in 1?%. The contour of the proximal segment of the OAs could be classified into straight, curved, and tortuous types. The ICA–OA angle defined by the angle between the approximate line of the proximal OA and the vertical line was also variable. The first bend of the OA corresponded to the anastomosis site with the external carotid system. The proximal medial bend was the origin of the posterior ethmoidal artery, and the distal medial bend was the origin of the anterior ethmoidal artery.

Conclusions

According to the results the OA not only possesses three characteristic bends, but also shows prominent individual variability and commonly shows bilateral asymmetry. The contour of the OA may be regulated by the anchor effect at the bend sites. PC MR Angiography is useful for visualizing the main trunk of the OA.     

Morphological analysis of the vertebral and basilar arteries in the Chinese population provides greater diagnostic accuracy of vertebrobasilar dolichoectasia and reveals gender differences

Purpose

Previous studies suggest that cerebral artery diameter and position differ with both gender and ethnicity, making diagnosis of vertebrobasilar dolichoectasia (VBD) difficult. Thus, the current study investigated the morphology and potential gender differences of the vertebral (VA) and basilar arteries (BA) in the Chinese population. The data collected also enabled some criteria to be suggested for the diagnosis of VBD by MRI.

Methods

A total of 200 healthy participants who underwent magnetic resonance imaging (MRI) were enrolled. The diameters of the BA and VA were measured using high resolution MRI and the height of the basilar artery bifurcation and the position of the basilar artery were also analyzed. The 95?% confident intervals (CI) of vessel diameter were calculated.

Results

The diameters of each artery measured, significantly differed with gender (p?Conclusions There are significant gender differences in the diameter of both the VA and BA, indicating that gender needs to be considered in the diagnosis of VBD. These results also provide much needed quantitative data for the diagnosis of VBD in Chinese people.     

Anatomical and CT angiographic study of superior gluteal neurovascular pedicle: implications for hip surgery

Purpose

To identify the site of incision with the lowest risk of injury of the superior gluteal neurovascular pedicle in the total hip arthroplasty with Hardinge’s direct lateral approach.

Methods

Eight fresh donated bodies were dissected and the branches of the superior gluteal nerve (SGN) and superior gluteal artery (SGA) were dissected. The distance between the SGA and the apex of greater trochanter (GT) was also evaluated in vivo in 29 patients by CT angiography.

Results

We observed 12 spray pattern and 4 transverse neural trunk pattern of the SGN. In all cases the nerve runs inferiorly to the artery, with a mean distance of 0.5 cm. At the CT angiography the average distance between the main branch of SGA and the GT was 5.2 cm, indicating a mean distance of 4.7 cm from the SGN to the GT. Terminal branches of SGA are found until 2.7 cm from GT.

Conclusions

This study analyzed the relationships between superior gluteal neurovascular pedicle and the GT in vivo (considering also the muscular tone), showing that during direct lateral access a safe area of 4.7 cm exists from the GT to the SGN and of 3.5 cm to its lower rami.     

A1 segment hypoplasia accompanied by AcomA aneurysms assessed with magnetic resonance angiography

Purpose

This study is to evaluate the use of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) at 3.0 T for the detection and classification of A1 segment hypoplasia based on a large case series and investigates the potential links with AcomA aneurysm occurrence.

Methods

Between January 2009 and June 2012, 8,013 patients underwent MRA examination at 3.0 T in our hospital. MRA was performed using 3D-TOF with volume rendering technique. The presence and location of A1 segment hypoplasia and AcomA aneurysm was reviewed.

Results

Among the 8,013 patients examined, 138 patients were identified with AcomA aneurysms. 425 patients were defined with A1 segment hypoplasia, among whom 303 right-sided A1 hypoplasia and 122 left-sided A1 hypoplasia. 60 of these 425 patients were confirmed with AcomA aneurysms, among them were 49 right-sided A1 hypoplasia. The prevalence of AcomA aneurysm with A1 segment hypoplasia was 14.1 %, which was much higher compared with that (1.0 %) of AcomA aneurysm without A1 segment hypoplasia (P < 0.001).

Conclusions

The incidence of right-sided A1 segment hypoplasia either accompanied with AcomA aneurysm or not was much greater than that of left-sided. Intracranial AcomA aneurysm development appeared to be associated with A1 segment hypoplasia.     

Positional relationships among the celiac trunk, superior mesenteric artery, and renal artery observed from the intravascular space

Purpose

To clarify the positional relationships among the celiac trunk (CT), the superior mesenteric artery (SMA), and the renal artery (RA) observed from the intravascular space to facilitate angiography.

Methods

After excluding six cadavers in which anatomic variation was found in the CT or SMA and four cadavers in which a curvature of 5° or more was observed in the aorta from 30 Japanese donor cadavers, we used the abdominal aortas of the remaining 20 cadavers as specimens. We made an incision in the maximum longitudinal diameter of the left RA (Lt. RA) and acquired an image of the intravascular space using a digital camera. The distance between the inferior borders of each vessel was used as the hypotenuse of a right-angled triangle. Lines parallel to the longitudinal diameter of the aorta and those parallel to the transverse diameter of the right-angled triangle were measured by a computer and expressed as relative distance indexes using the transverse diameter of the aorta at the Lt. RA level as a reference point.

Results

The transverse diameter of the aorta was 20.1 ± 2.9 mm, and the relative distance indexes for longitudinal/transverse lines between each vessel were 1.61/0.35 between Lt. RA and CT, 0.84/0.48 between Lt. RA and SMA, and 0.78/0.13 between CT and SMA. The angle between the transverse axis of the abdominal aorta and the linear line connecting CT and SMA was 80.2° ± 9.4°. The branching point of CT in relation to SMA was located at the upper left in 80 % (n = 16), on the same line in 15 % (n = 3), and at the upper right in 5 % (n = 1) of the subjects.

Conclusions

The relative distance indexes determined in this study will facilitate navigation during catheter insertion, particularly for those with little angiography experience, and thus reduce patient risk.     

An anatomic study of the inferior oblique nerve with high-resolution magnetic resonance imaging

Objective

To investigate anatomic features of the inferior oblique nerve (IObN) by high-resolution magnetic resonance (MR) imaging and cadaveric dissection.

Methods

This study enrolled 100 consecutive outpatients, who underwent 3.0 T MR imaging equipped by the 32-channel head coil. The T2-weighted imaging data of IObN were extracted for analysis and compared with the findings of microsurgical dissection in 14 orbits.

Results

50 male and 50 female subjects allotted to the imaging study were aged from 11 to 78 years. In 94 % sides, the IObN was found to separate from the inferior rectus muscle (IRM) at the level just behind to the posterior pole of the bulb. At the midpoint of the IObN part coursing along the orbital floor and above or adjacent to the infraorbital nerve and artery complex, the mean distance from the lateral margin of the IRM was 1.0 mm on the right and 0.9 mm on the left. The IObN showed upward direction change just below the belly of the inferior oblique muscle and innervated to it at the equator level in 78 sides on the right and 89 on the left. Dissected specimens revealed the consistent morphological findings of the IObN.

Conclusions

The IObN seems to be a relatively consistent structure. Anatomic information on the IObN and surrounding structures that are provided by high-resolution MR imaging can be a help for safe surgery.     

Persistent trigeminal artery: a cross-sectional study based on over 3 years conventional angiography,CT angiography and MR angiography images

Purpose

The trigeminal artery is one of the four primitive anastomosis established between the internal carotid artery and the vertebrobasilar system that regresses at the sixth week of embryonic development. Its persistence in adult life (PTA) is usually found incidentally. The aim of this study is to determine its prevalence, main characteristics and clinical significance.

Methods

A cross-sectional study was performed over the last 3 years, 2012–2014, to analyze images performed on conventional angiography, CT angiography and MR angiography of patients who attended the Neuroradiology Department of the Hospital Universitario Doce de Octubre in Madrid, Spain, to control their underlying pathology.

Results

Nine cases of PTA were found (prevalence 0.37 %, two men, seven women; three right, six left; age range 13–88 years). Eight PTA emerged from the cavernous ICA and one from the petrous segment. Six cases were lateral or petrosal type and one was medial or sphenoidal type. The whole PTAs anastomosed the BA, six at the middle third and three at the distal third. Weon et al.’s type 3 was predominant. CVD incidence was 55.6 % and aneurysm incidence was 22 %.

Conclusions

PTA prevalence was similar to those previously reported, being commonly left-sided, Salas et al.’s lateral or petrosal type, Weon et al.’s type 3 and with no gender predominance. CVD and aneurysms incidence in the presence of a PTA were higher than in general population. Its anatomical relations make it essential to consider its presence and directional blood flow when planning endovascular and neurosurgical treatments.

     

Role of ovarian artery-to-uterine artery anastomoses in uterine artery embolization: initial anatomic and radiologic studies

Purpose

To explore the anatomic features of normal human ovarian artery-to-uterine artery anastomoses and their impact on uterine artery embolization (UAE).

Methods

Using slice computed tomography (CT) scanning and vascular casting; models of the uterine arterial vascular network were constructed using five sets of uterus, bilateral adnexa and vagina from normal adult females. The anatomy and characteristics of these models were then studied.

Results

Both the casting specimen and the CT-reconstructed model showed the ovarian artery-to-uterine artery anastomoses clearly. Each was composed of the ovarian branch of the uterine artery and the ovarian branch of the ovarian artery. All 10 ovarian artery-to-uterine artery anastomoses were formed by direct connection between the ovarian branch of the uterine artery and the ovarian branch of the ovarian artery.

Conclusions

Thin slice CT scanning combined with vascular casting is a useful method to study the small arterial network. The anastomoses between the ovarian branch of the uterine artery and the ovarian branch of the ovarian artery were formed mainly by direct connection. The implications of the ovarian artery-to-uterine artery anastomoses on UAE are unclear; further function assessments are needed.