When Does Pcom Do Background Checks Sdn

BMC Ear Olfactory organ Throat Disord. 2006; half dozen: v.

The posterior communicating arteries in the patients with sudden deafness: evaluation with magnetic resonance imaging (MRA)

Yoshito Tsushima

^aneDepartment of Diagnostic Radiology and Nuclear Medicine, Gunma Academy Hospital, 3-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan

^twoDepartment of Radiology, Motojima Full general Hospital, 3–viii Nishi-Honcho, Ohta, Gunma 373-0033 Japan

Ayako Taketomi-Takahashi

¹Section of Diagnostic Radiology and Nuclear Medicine, Gunma University Hospital, three-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan

^twoDepartment of Radiology, Motojima General Infirmary, three–viii Nishi-Honcho, Ohta, Gunma 373-0033 Japan

Keigo Endo

¹Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Hospital, iii-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan

²Section of Radiology, Motojima Full general Hospital, 3–8 Nishi-Honcho, Ohta, Gunma 373-0033 Japan

Received 2005 Aug 4; Accepted 2006 Mar 21.

Abstract

Groundwork

A strong association was suggested betwixt a non-functioning posterior communicating avenue (Pcom) of the circle of Willis and sudden deafness (SD). The purpose of this written report was to determine the rate of depiction of Pcom on magnetic resonance angiography (MRA) in patients with SD.

Methods

Sixteen patients with SD (47.7 +/- 13.3 years; range, 24 – 76 years; 9 males) were evaluated with intracranial MRA equally well as magnetic resonance imaging (MRI) of the caput. The depiction of Pcom on MRA was correlated with the laterality of SD. One hundred twenty-eight controls (49.1 +/- 8.iv years; range, 22 – 66 years; 87 male) were selected from neurologically normal subjects who underwent MR examinations as a part of an annual medical bank check-up in our hospital.

Results

Four (25%) of sixteen SD patients had bilateral Pcom on MRA, four patients had unilateral Pcom and 8 patients had bilaterally absent-minded Pcom These results were not significantly unlike from the controls (p = 0.96). In six (37.five %) of 16 SD patients, the ipsilateral Pcom was nowadays on MRA, and 104 (40.6%) of 256 Pcom were present in 128 normal controls (p = 0.81).

Conclusion

Since there was no link between the occurrence of SD and the absenteeism of the ipsilateral Pcom, our results cannot support the hypothesis that the absence of Pcom may be a gamble cistron for the occurrence of SD.

Background

Sudden deafness (SD) accounts for approximately one% of all cases of sensorineural hearing loss, and almost cases of spontaneous SD have no identifiable crusade [1]. Numerous clinical and laboratory investigations have attempted to place the case of this disorder, and although the suggested causes include circulatory disorders, viral infections, and labyrinthine trauma, there is no definitive proof.

Recently, De Felice et al. [ii] took ultrasonographic doppler menstruation measurements of the extracranial carotid and vertebrobasilar systems and independent audiological measurements in SD patients, and suggested a potent association between a non-performance posterior communicating artery (Pcom) of the circle of Willis and SD. Although the mechanisms for the observed association remain unknown, their observations may be consistent with a circulatory pathogenesis of idiopathic SD.

We performed magnetic resonance imaging (MRI) with and without contrast fabric and magnetic resonance angiography (MRA) of the circle of Willis in 16 patients with SD and 48 controls subjects matched for age and sex in gild to make up one's mind the possible correlation between the absenteeism of Pcom and SD.

Methods

In our hospital all patients with SD undergo enhanced MRI of the head and MRA of the circle of Willis in order to depict possible etiology of SD, in item cerebellopontine angle tumors. During a catamenia of one year, sixteen patients with unilateral SD (mean +/- standard deviation, 47.7 +/- 13.3 years; range, 24 – 76 years; nine males) were evaluated with intracranial MRI and MRA, and all of these patients were included in this study. Past definition, SD is rapid (over a period of upwardly to 3 days) sensorineural hearing loss. Hearing loss was divers equally a hearing level loss of 30 dB or more than in at least iii contiguous audiometric frequencies. One patient was diabetic, but none of the xvi patients were hypertensive. There was no evidence of cranial nervus abnormalities except for the eighth nervus, and general physical examinations were otherwise normal. No patients had any history of trauma, intense noise exposure, or recent viral illness, which may result in sensorineural hearing loss. Three patients had vertigo and one had tinnitus. These medical evaluations were all performed in the otorhinolaryngology department of our hospital.

All subjects were studied on the same 1.0-T MR scanner (Magnex^®, Shimadzu, Kyoto, Japan), including axial T1-weighted spin repeat (SE; TR = 450 ms, TE = 15 ms), and proton-density-weighted and T2-weighted fast SE (TR = 4000 ms, TE = 20 and 100 ms, echo railroad train length = 8). The matrix was 256*192 and the section thickness was 5 mm with a gap of two.5 mm. MRA was likewise performed using time-of-flight technique (TR = 40 ms, TE = 9 ms, flip angle = 20°), and 16 projections of the MRA of the circle of Willis were created by a maximum-intensity projection (MIP) algorithm around the caput-to-foot centrality and right-to-left axis. Coronal and axial T1-weighted images with contrast enhancement (TE = 450 ms, TE = 15 ms) were also obtained in all subjects past intravenous administration of Gd-DTPA (Magnevist^®, Nihon Schering, Osaka, Nihon). The matrix was 256*192 and a section thickness was iii mm with a gap of 1 mm. All MR images were interpreted by a lath-certified diagnostic radiologist, and all MR abnormalities were recorded. MRA findings were also recorded, and the particular attention was paid for the presence of the Pcom.

The command subjects consisted of 128 patients (49.ane +/- eight.four years; range, 22 – 66 years; 87 male) in whom no important abnormal findings were observed on MRI and MRA. They were selected from subjects who underwent MR examinations, which were performed during the same menses of the SD subjects, as a function of an almanac medical cheque-upward in our hospital. They were neurologically healthy, no cochlear or vestibular symptoms were nowadays, and normal standard pure tone audiometry was inside normal limits. The protocol of MRI and MRA examinations was the aforementioned as that for SD patients, although no enhanced T1-weighted images were obtained.

Student t exam and Fisher's verbal examination were employed for statistical analyses, and a p value of 0.05 or less was considered pregnant. In our infirmary, no approving of the ethics committee was necessary for this kind of a retrospective study. The Declaration of Helsinki principles was followed.

Results

4 (25%) of sixteen SD patients had bilateral Pcom on MRA, four patients had a unilateral Pcom and 8 patients had a bilaterally absent Pcom (Figure 1). These results were not significantly dissimilar from that of the controls (p = 0.96; Table one). Correlation between the presence of the Pcom and the side of SD is shown in Table 2. In half-dozen (37.5 %) of 16 SD patients, the ipsilateral Pcom was present on MRA, and 104 (40.vi%) of 256 Pcom were nowadays in 128 normal controls (p = 0.81).

Table 1

Posterior communicating artery (Pcom) in SD patients and controls. There was no association betwixt the type of subject and the type of Pcom (p = 0.96, Fisher's verbal test).

	Posterior communicating artery (Pcom)
	Bilaterally present	Unilaterally present	Bilaterally absent	Full

SD patients	4 (25%)	4 (25%)	8 (l%)	16
Controls	35 (27.three%)	34 (26.6%)	59 (46.1%)	128

Full	39	38	67	144

Tabular array 2

Ipsilateral posterior communicating artery (Pcom) in SD patients and controls. At that place was no association betwixt the type of subject and the presence of ipsilateral Pcom (p = 0.81, Fisher's verbal test).

	Ipsilateral Posterior communicating avenue (Pcom)
	Nowadays	Absent	Total
SD patients	half-dozen (37.five%)	ten (62.5%)	xvi
Controls	104 (40.6%)	152 (59.four%)	256 *

* Two hundreds fifty-vi Pcom in 128 command subjects.

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MRA of a 47-year-old male person patient with right SD. The right Pcom was absent, simply the left i (pointer) is clearly demonstrated.

In the SD patients and controls, no vascular abnormalities, such as aneurysm and arterial stenosis, were observed on MRA. In i patient with SD, a small arachinoid cyst in the eye cranial fossa was demonstrated on MRI. Otherwise, on MRI with and without contrast enhancement, no abnormal findings, such every bit tumor, infarction and degenerative diseases, were observed in either the SD patients or controls. At that place was no differences between the SD patients and control subjects in age (p = 0.69) and sexual activity (p = 0.35).

Discussion

Pcom is a potential collateral pathway through which adequate distribution of cerebral blood menstruation tin be maintained in case of impaired of decreased menstruation through 1 of more of its proximal feeding vessels, and a small or absent ipsilateral Pcom is a risk cistron for ischemic cognitive infarction in patients with internal carotid artery occlusion [3,4]. It has been also reported that the symptom complex of vertebrobasilar insufficiency can be correlated with the absence of Pcom [5]. From the viewpoint of a circulatory pathogenesis of SD, the absence of Pcom might also contribute to the occurrence of SD [2]. All the same, our electric current information did non demonstrate any correlation between an absent Pcom and the development of SD, and thus failed to support the hypothesis that the absence of Pcom may be a take a chance factor for the occurrence of SD.

According to normal reference values for the presence of the anatomic variants of the circle of Willis on MRA using 1.5-T unit [4], the prevalence of an entirely complete configuration of the circumvolve of Willis is just 54%. Hoksbergen et al. [six] compared MRA findings to transcranial colour duplex sonography, and ended that if Pcom tin can exist visualized by MRA, information technology can be assumed with a high level of confidence that collateral flow is possible. In our written report, the prevalence of the presence of ipsilateral Pcom in SD patients was 37.5%, and this prevalence was not significantly dissimilar compared to the normal controls (twoscore.6%).

Since our MR unit of measurement was 1.0-T, the spatial resolution may be slightly lower than a 1.5-T unit of measurement. Therefore, some very small Pcoms might not be depicted on MRA, possibly resulting in a college fake negative rate. In a previous report using 1.5-T MR system [6], the posterior collateral pathway was judged nonfunctional on MRA in 31% of all cases, and this prevalence was slightly lower compared to our results (59.four%). However, even if Pcoms with a very minor bore were depicted on MRA, the overall consequence in our study would not change.

Our examined population was Japanese and De Felice et al. [2] studied a Caucasian population. This deviation may exist the reason for the unlike results, simply to our knowledge, there have been no reports showing racial differences of Willis anatomy.

In spite of our results, circulatory disorders may notwithstanding be a possible cause of SD. If only a pocket-size percentage of SD is due to circulatory disorders, it would not exist surprising that no statistically significant departure in the absence of Pcom can be observed. More detailed analyses with a large number of SD patients are encouraged to elucidate the possible circulatory pathogenesis of SD.

Conclusion

Since there was no link between the occurrence of SD and the invisible Pcom on MRA, our results cannot back up the hypothesis that the absenteeism of Pcom may be a adventure factor for the occurrence of SD.

List of abbreviations

MIP: maximum-intensity projection

MR: magnetic resonance

MRA: magnetic resonance (MR) angiography

MRI: magnetic resonance (MR) imaging

Pcom: posterior communicating artery

SD: sudden deafness

SE: spin echo

TE: echo time

TR: repetition time

Competing interests

The author(s) declare that they accept no competing interests.

Authors' contributions

YT participated in the pattern of the study and performed the statistical analysis. KE conceived of the written report, and participated in its blueprint and coordination and helped to draft the manuscript. Both authors read and approved the final manuscript.

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