能幫翻 MRA(血管磁震照影)的論文嗎?

懂MRA的請幫忙翻譯一下或介紹有合適的翻譯軟體?

Contrast-Enhanced Carotid Magnetic Resonance Angiography:

Comparison of Single-Dose and Double-Dose of Gadolinium

Using the Randomly Segmented Central k-Space

Ordering Technique

Yu-Chun Lin, RT; Shu-Hang Ng, MD; Jian-Chuan Chen, MS;

Alex Mun-Ching Wong, MD; Yau-Yau Wai, MD

Background: The aim of this study was to evaluate whether the single dose of gadolinium

is sufficient for contrast-enhanced magnetic resonance angiography (MRA)

of carotid arteries with the use of newly developed randomly segmented central

k-space ordering technique called contrast-enhanced timing-robust

angiography (CENTRA).

Methods: A total of 44 patients underwent carotid MRA in a 1.5T MR scanner using a

fluoroscopically monitored, manually triggered, CENTRA pulse sequence.

Patients were randomly assigned into two groups according to the dose of

contrast medium (gadolinium chelate) administered: group 1 referred to

those who received double doses (0.2 mmol/kg) and group 2 received single

doses (0.1 mmol/kg). The contrast-to-noise (CNR) ratios of the seven regions

of interest were calculated. The delineation of nine vascular regions and the

degree of venous overlay were evaluated by two blinded readers on a fivepoint

scale.

Results: For quantitative evaluation, the CNRs at the brachiocephalic artery were

greater in patients in group 1 than that in group 2 (p = 0.015), while the differences

did not differ between the two groups for the remaining regions of

interest (p > 0.05). For qualitative evaluation, there were no significant differences

between the two groups in delineation of nine vascular regions and

venous overlaying (p > 0.05).

Conclusion: With the use of the CENTRA technique, carotid MRA may be performed

using a single dose of gadolinium and the image quality is comparable to that

of the standard double dose protocol.

(Chang Gung Med J 2005;28:485-91)

Key words: magnetic resonance image (MRI), MR angiography (MRA), carotid artery.

From the Department of Diagnostic Radiology, Chang Gung Memorial Hospital Taipei; Department of Medical Imaging and

Radiological Sciences, Chang Gung University, Taoyuan.

Received: Oct. 28, 2004; Accepted: May 12, 2005

Address for reprints: Dr. Yau-Yau Wai, Department of Diagnostic Radiology, Chang Gung Memorial Hospital, No. 5, Fushing St.,

Gueishan Shiang, Taoyuan, Taiwan 333, R.O.C. Tel.: 886-3-3281200 ext. 2575; Fax: 886-3-3971936; E-mail:

yauwaiwu@ms4.hinet.net

Magnetic resonance angiography (MRA) has

emerged as a useful technique for assessing

carotid circulation. It is noninvasive and has the

advantage of providing images similar to conven-

Original Article 485

Chang Gung Med J Vol. 28 No. 7

July 2005

Yu-Chun Lin, et al

Contrast-enhanced carotid MRA

486

tional angiography.(1) In contrast to time-of-flight

MRA,(2-5) which does not require the administration

of contrast medium, contrast-enhanced MRA takes

less time perform and its high accuracy in revealing

carotid artery stenosis has been well recognized.(1,6-9)

In contrast-enhanced MRA, the time of contrast

material injection and the timing of image acquisition

are crucial to obtain optimal arterial contrast and

to avoid overlaying by the internal jugular veins. In

order to obtain a high quality MRA, double doses of

contrast medium are recommended to keep the

intravascular concentration of contrast medium high

and constant during the data acquisition.(10,11)

However, proper timing of contrast enhancement is

still crucial and has limited the success of contrastenhanced

MRA.

A new MR technique of randomly segmented

central k-space ordering has been developed. It is

also called contrast-enhanced time-robust angiography

(CENTRA).(12) This technique samples the central

phase-encoding view during the early arterial

phase when the pulse sequence is triggered by the

arrival of contrast material in the selected area, so it

makes contrast-enhanced MRA more robust in timing.

This is a modified centric k-space ordering technique

which is different from the elliptic centric view

ordering.(13) It has been shown that the CENTRA

technique with the administration of double doses of

contrast medium provides high spatial resolution,

wide anatomic coverage and effective venous overlying

avoidance in carotid vessels.(12) Theoretically, the

more accurate timing of acquisition with such a dedicated

k-space filling design may allow the use of a

lower dosage of the contrast medium. Gadolinium is

an expensive contrast medium for MRI, if the dosage

can be reduced, it would help cut the costs of the

MRI examination. The aim of this study was to

determine the feasibility of the CENTRA technique

using a single dose of gadolinium in assessing the

extracranial carotid and vertebral artery system.

METHODS

From June through August 2004, 44 consecutive

patients (25 men, 19 women; age range, 40-78 years;

mean age, 61.3 9.1 years) with suggested cerebrovascular

disease were referred for MR angiographic

evaluation of the extracranial carotid and

vertebral arteries. The patients’ average weight was

71.8 9.3 kg (range, 54-86 kg). All patients were

initially evaluated using duplex ultrasonography

(US) for the carotid circulation. Table 1 shows the

basic characteristics and US findings of the patients.

MR imaging was performed using a 1.5T MR

scanner (Intera; Philips Medical System, Best, the

Netherlands) with a maximal achievable gradient

amplitude of 30 mT/m, a rise time of 0.2 msec, and a

slew rate of 150 T/m/sec. A commercially available

phased-array coil (Synergy head and neck coil;

Philips Medical Systems, Netherlands) that can

cover the regions of the head, neck, and upper chest

was used. Before positioning the patient, a 20-gauge

intravenous catheter was positioned in the antecubital

vein.

Each patient was randomly assigned into one of

the two groups regarding the amount of gadolinium

chelate injection (Omniscan; Nycomed, Oslo,

Norway): group 1 (n = 22) received double doses of

gadolinium of 0.2 mmol/kg and group 2 (n = 22)

received single doses of 0.1 mmol/kg. Contrast

medium was injected at a rate of 2 ml/sec, followed

by flushing with 10 ml of saline solution at the same

rate using an MR-compatible power injector

(Optistar; Mallinckrodt Inc., Ohio, USA). Contrastenhanced

three-dimensional (3D) MRA was trigged

by two-dimensional real-time MR fluoroscopy in the

coronal plane.(14) When the MR fluoroscopy revealed

the arrival of the bolus of contrast material in the left

atrium, the angiographic pulse sequence was started

with a delay of 4 seconds. The protocol of the MR

fluoroscopy was as the following: a TR/TE/Flip

angle = 3.4 ms/1.0 ms/40°, a field of view of 450

Table 1. Basic Characteristics of the Study Population

Group 1 (N = 22) Group 2 (N = 22)

0.2 mmol/kg 0.1 mmol/kg p value*

Age (year) 62.8 9.4 59.8 8.7 0.29

Body weight (kg) 72.3 8.9 71.3 9.4 0.74

Heart rate (beat/min) 74.6 6.4 71.9 7.3 0.20

Average total dose of gadolinium (ml) 28.9 3.6 14.3 1.9

Duplex ultrasonography findings

Normal 11 (50%) 12 (55%)

Mild or moderate stenosis† 9 (41%) 7 (31%)

Severe stenosis or occlusion† 2 (9%) 3 (14%)

* Two-sample t-test

† Stenosis or occlusions were suspected in one or more than one vessels of

supraaortic arteries.

Chang Gung Med J Vol. 28 No. 7

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Yu-Chun Lin, et al

Contrast-enhanced carotid MRA

487

mm, a section thickness of 10 mm, and an image

acquisition rate of 1 second.

The angiographic MR sequence was performed

using a technique of randomly segmented central kspace

ordering known as CENTRA. The parameters

of CENTRA were as follows: a 3D gradient-echo

sequence with 4.6/1.67, a flip angle of 40°, a rectangular

field of view of 50%, an image matrix of 416

416 on a 300-mm field of view with 120 partition

of 0.7 mm. Total acquisition time was 58 seconds. A

single subtracted 3D imaging was calculated by subtracting

the unenhanced set from the enhanced set.

Maximum intensity projection reconstructions of the

subtracted images were generated from single partitions

(nine projections at 20° increments within a

180° rotation). All the studies were performed by the

single MR imaging technician.

For the quantitative evaluation, the mean signal

intensity of the vessel lumen (SIV) in the seven

regions of interest, including the brachiocephalic

artery, bilateral carotid bifurcations (right and left),

bilateral intracranial internal carotid arteries, and

bilateral vertebral arteries, and of their surrounding

tissue (SIB), were measured (Fig. 1). Image noise

( ) was measured as the standard deviation from the

signal intensity of the air surrounding the patient.

The contrast-to-noise ratio (CNR) of each region of

interest was calculated using the following formula:

CNR = (SIV - SIB)/ .

For the qualitative assessment, the images were

reviewed in a blinded fashion by two investigators

who separately reviewed MR images in a randomized

order for scoring the delineation of nine vascular

regions (brachiocephalic artery, common carotid

arteries, internal carotid arteries, external carotid

arteries, vertebral arteries, basilar artery, middle cerebral

arteries, anterior cerebral arteries and posterior

cerebral arteries) and the degree of venous overlay.

The rating scale for delineation of the nine vascular

regions was as follows: (1) excellent delineation of

the arterial lumen and sharp edge; (2) good delineation

of the arterial lumen with a mild blurring of

the edge; (3) fair delineation of the arterial lumen

with noticeable blurring of the edge; (4) poor delineation

of the arterial lumen with a major edge blurring;

and (5) not assessable. The rating scale for

venous overlay was as follows: (1) internal jugular

vein not visible; (2) internal jugular vein barely visible;

(3) noticeable signal intensity in internal jugular

vein; (4) comparable signal intensity in internal jugular

vein and internal carotid artery; and (5) greater

signal intensity in internal jugular vein than in internal

carotid artery.

Statistical analyses were performed using Excel

software (Microsoft, Seattle, Wash, USA) using the

Fig. 1 Maximum intensity projection image of the carotid

MR angiography with the CENTRA technique, showing the

seven regions of interest (the black blank circle) at the brachiocephalic

artery, bilateral carotid artery bifurcations, bilateral

intracranial internal carotid arteries, and bilateral vertebral

arteries.

Chang Gung Med J Vol. 28 No. 7

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Yu-Chun Lin, et al

Contrast-enhanced carotid MRA

488

two-tailed Student t test. A p value less than 0.05

was considered a statistically significant difference.

All the values were presented as means SDs. The

degree of agreement between observers was determined

using the statistic. Agreement was classified

as moderate ( = 0.40-0.69), good ( = 0.70-

0.89), or excellent ( = 0.90-1.00).

RESULTS

All of our patients tolerated the procedures well.

There were no significant differences in age, body

weight and heart rate between the two groups of

patients (p > 0.05). The procedure lasted approximately

30 minutes for each patient, including all the

routine MR imaging and MRA examinations.

Quantitative assessment results of the CNRs of the

seven regions are shown in Table 2. For the brachiocephalic

artery, the CNRs in group 1 were significantly

higher than those in group 2 (p = 0.015). For

bilateral carotid bifurcations, bilateral intracranial

internal carotid arteries and bilateral vertebral arteries,

there were no statistically significant differences

in CNR between these two groups (p > 0.05).

The qualitative rating for the delineation of nine

vessels and the venous overlapping of the two groups

are summarized in Table 3. The brachiocephalic

artery, common carotid arteries, internal carotid

arteries, external carotid arteries, vertebral arteries

were visible on all studies. Parts of the vessels were

not visible during the scoring because of severe

stenosis or occlusion. The basilar artery was visible

in 41 (93%) of 44 patients. The middle cerebral

arteries were visible in 80 (91%) of the 88 readings.

The anterior cerebral arteries were visible in 76

(86%) of the 88 readings. The posterior cerebral

arteries were visible in 82 (93%) of the 88 readings.

The internal jugular vein was not seen or was just

barely visible in 66 (75%) of the 88 readings. There

were no statistically significant differences between

these two groups (p > 0.05) for such qualitative evaluations.

Interobserver agreements for all evaluations

were good or excellent, ( range, 0.84 - 0.95).

DISCUSSION

Contrast-enhanced MRA is increasingly been

used in imaging of carotid arteries in the past few

years.(6-8,15,16) Intravenous injection of contrast material

in a bolus manner generates a stronger signal in the

patent vessels with better background suppression in

a shorter examination time than other injection techniques.

However, overlapping of the jugular vein on

the carotid bifurcation has been one of the main

drawbacks. Recently, the centric k-space ordering

technique has remarkably improved the quality of

contrast-enhanced MRA of the carotid arteries,

resulting in high spatial resolution and sufficient

venous suppression.(13,17) In conventional elliptic centric

view ordering technique, the samples in the

phase-encoding direction are reordered so that the

data in the center of k-space is acquired first. It is

crucial with this technique that the first views correspond

with the bolus peak. Therefore, timing of the

Table 2. CNRs of the 7 Regions of Interests with 2 Different Doses of

Gadolinium Injected

CNR

ROI Group 1 Group 2 p-value

(0.2 mmol/kg) (0.1 mmol/kg)

Brachiocephalic artery 91.36 6.64 86.82 5.12 0.015

Left CCA 87.68 6.68 89.82 7.88 0.338

Right CCA 87.27 5.51 89.05 7.93 0.394

Left intracranial internal

carotid artery 89.36 5.76 87.14 4.81 0.171

Right intracranial internal

carotid artery 90.45 8.31 88.50 7.75 0.424

Left vertebral artery 87.68 7.18 84.77 7.45 0.194

Right vertebral artery 87.25 7.89 85.18 8.13 0.392

Abbreviation: CNR: contrast to noise ratio; ROI: region of interest;

CCA: common carotid artery.

Table 3. Comparison of Mean Scores of Qualitative Evaluations in 2 Groups

Score

Group 1 Group 2 p-value

(0.2 mmol/kg) (0.1 mmol/kg)

Arteries visualized

Brachiocephalic (N = 44) 2.2 0.7 2.5 0.8 0.069

Common carotid (N = 88) 1.7 0.7 1.6 0.7 0.534

Internal carotid (N = 88) 1.8 0.6 2.0 0.7 0.318

External carotid (N = 88) 2.0 0.9 2.2 1.0 0.248

Vertebral (N = 88) 2.7 0.9 2.4 0.8 0.123

Basilar (N = 41) 2.5 0.7 2.3 0.8 0.255

Middle cerebral (N = 80) 2.6 0.7 2.8 0.9 0.277

Anterior cerebral (N = 76) 3.2 0.8 3.6 1.1 0.099

Posterior cerebral (N = 82) 3.5 0.9 3.7 1.0 0.242

Venous overlay (N = 44) 2.2 0.9 1.9 0.8 0.090

Chang Gung Med J Vol. 28 No. 7

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Yu-Chun Lin, et al

Contrast-enhanced carotid MRA

489

contrast medium bolus peak is critical, however, spatial

resolution and coverage are still limited.

In this study, we used the CENTRA technique to

solve the main weakness of the conventional elliptic

centric view ordering technique. The CENTRA

acquires data randomly in the central sector during

the full arterial phase, so the first view does not have

to correspond with the bolus peak. After data has

been acquired in the contrast-determining central

disk of the k-space, the acquisition data can extend

well beyond the actual arterial passage of the bolus,

with preservation of arterial phase image contrast.

Since the available acquisition time is longer, there is

sufficient time for sampling data for high imaging

matrices. In our patients, we used the acquisition

time of 58 seconds that yielded matrix sizes of 416

416. This gives higher spatial resolution compared

with conventional elliptic ordering technique

(176 256 matrix at 20 seconds acquisition

time).(17,18)

To our knowledge, few researchers(12,13,19) have

addressed the influence of the gadolinium dosage on

image quality of carotid MRA with the central kspace

ordering techniques. Most of the available

clinical studies reported the promising results of

carotid MRA with a fixed volume of gadolinium

ranging between 20-25 ml.(6,15,20,21) Luccichenti et al.(19)

used the elliptically ordered sequence to perform

MRA and claimed that optimal image quality would

be obtained with gadolinium doses greater than 0.16

mmol/kg of bodyweight in the carotid vessels. The

CENTRA technique application was first investigated

by Willnek et al.(12) They concluded that the CENTRA

was a robust technique for contrast-enhanced

3D MRA and yielded high-quality diagnostic images

in patients suggested of having cerebrovascular disease.

In their study, double doses (0.2 mmol/kg) of

gadolinium injection were used.

Our results showed that the image quality of

MR angiography in carotid arteries using the CENTRA

technique with a single dose (0.1 mmol/kg) of

gadolinium was comparable with that obtained using

double doses (0.2 mmol/kg) both quantitatively and

qualitatively. The CNR of brachiocephalic artery in

the double dose group was higher than that in the

single dose group. This may be due to the widened

lumen of the brachiocephalic artery, resulting in the

reduction in intravascular concentration of gadolinium

in the single-dose group during data acquisition.

However, this did not affect the delineation of the

brachiocephalic artery since there were no significant

differences between the two groups in qualitative

evaluation of this vessel.

In addition, we used fluoroscopic monitoring of

contrast arrival at the carotid arteries to trigger image

acquisition so that the arterial phase can be selectively

imaged and the venous overlapping can be

reduced. The triggering method can provide a comprehensive

evaluation of the carotid arteries including

all vessel segments from the aortic arch to the

circle of Willis.(20,22) However, the success of this

technique relies on the experience of the operator.

Therefore, in our study, all the scans were performed

by a single technician in order to avoid such interoperator

variation. Our results showed no significant

differences between the two groups in the evaluation

of the venous overlapping. Further studies are

required to investigate the reliability of the fluoroscopic

triggering technique among different operators.

The accuracy of contrast-enhanced MRA for the

evaluation of carotid artery disease has been corroborated

by several investigators.(6,19,22) In our study, however,

we compared the imaging quality of two groups

using different doses of contrast medium but we did

not assess their corresponding accuracy in disease

evaluation. This was because none of our patients

underwent catheter angiography. Further clinical

studies are required to assess the diagnostic accuracy

of the CENTRA technique with the reduced dosage

of contrast medium injection.

In conclusion, the results of this study suggests

that with the use of the CENTRA technique, contrast-

enhanced MRA of carotid arteries using single

dose contrast medium may provide comparable

image quality to that using double doses.

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5 Answers

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  • 必可
    Lv 5
    2 decades ago
    Favorite Answer

    http://www.systransoft.com/index.html

    這個翻譯軟體還不錯用~~

    ================================

    翻譯結果, 請參考:

    對比改進的頸動脈磁共振血管學:

    唯一藥量釓比較和雙重藥量

    使用任意地被分割的中央k 空間

    定貨的技術

    于春林, RT; Shu 垂懸Ng, MD; Jian-Chuan 陳, 女士;

    亞歷克斯用力嚼的Wong, MD; Yau-Yau Wai, MD

    背景: 這項研究的目標將評估是否釓唯一藥量

    是充足的為對比改進的磁共振血管學(MRA)

    頸動脈以對最近被開發的任意地被分割的中央的用途

    k 空間定貨的技術叫對比改進的時間健壯

    血管學(中心) 。

    方法: 一共計44 名患者接受了頸動脈MRA 在1.5T 先生掃描器使用a

    fluoroscopically 監測, 手工觸發, 中心脈衝序列。

    患者任意地被分配了入二個小組根據藥量

    對比媒介(釓螯合) 執行了: 小組1 提到了

    那些接受雙重藥量(0.2 mmol/kg) 並且小組2 接受唯一

    藥量(0.1 mmol/kg) 。七個地區的對比對噪聲(CNR) 比率

    利益被計算了。九個血管地區的描述和

    程度多血脈性的覆蓋物由二個盲人讀者評估了在fivepoint

    標度。

    結果: 為定量評估, CNRs 在brachiocephalic 動脈是

    偉大在患者在小組1 比那在小組2 (p = 0.015), 當區別

    沒有不同在二個小組之間為殘餘的地區

    興趣(p > 0.05) 。為定性評估, 沒有重大區別

    在二個小組之間在九個血管地區的描述和

    多血脈性覆蓋(p > 0.05) 。

    結論: 以對中心技術的用途, 頸動脈MRA 也許執行

    使用釓和圖像唯一藥量質量與那是可比較的

    標準雙重藥量協議。

    (Chang Gung Med J 2005;28:485-91)

    關鍵詞: 磁共振圖像(MRI), 血管學(MRA), 頸動脈先生。

    從診斷放射科的部門, Chang Gung 紀念醫院臺北; 醫療想像的部門和

    放射學科學, Chang Gung 大學, Taoyuan 。

    接受: 2004 年10月28,; 接受: 2005 年5月12 日

    地址為重印: Yau-Yau Wai, 診斷放射科, Chang Gung 紀念醫院, 第5 的部門博士, Fushing St.,

    Gueishan Shiang, Taoyuan, 臺灣333, R.O.C 。Tel.: 886-3-3281200 ext 。2575; 電傳: 886-3-3971936; 電子郵件:

    yauwaiwu@ms4.hinet.net

    磁共振血管學(MRA) 有

    湧現作為估計的一個有用的技術

    頸動脈循環。它是非侵入性的和有

    提供圖像好處相似與conven-

    原始的文章485

    Chang Gung Med J 卷28 第7

    2005 年7月

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    486

    tional angiography.(1) 與時間飛行對比

    不要求管理的MRA, (25)

    對比媒介, 對比改進的MRA 作為

    較少時間執行和它的高準確性在顯露

    頸動脈狹窄是很好recognized.(1,6-9)

    在對比改進的MRA, 對比的時期

    物質射入和圖像承購時間

    是關鍵獲得優選的動脈對比和

    避免覆蓋由內部頸部的靜脈。在

    命令獲得高質量MRA, 雙重藥量

    對比媒介被推薦保持

    對比媒介的血管內的集中高

    並且常數在資料acquisition.(10,11) 期間

    但是, 對比改進適當的時間是

    關鍵和限制了成功contrastenhanced

    MRA 。

    一個新先生技術任意地分割

    中央k 空間定貨被開發了。它是

    並且叫的對比改進的時間健壯血管學

    (CENTRA).(12) 這個技術抽樣中央

    階段內碼看法在早期動脈期間

    階段當脈衝序列由觸發

    到來對比材料在選擇的區域, 如此它

    牌子對比提高了MRA 健壯在時間。

    這是一個修改過的中心k 空間定貨的技術

    哪些是與橢圓中心看法不同

    ordering.(13) 它被顯示了中心

    技術以雙重藥量的管理

    對比媒介提供高空間決議,

    寬解剖覆蓋面和有效多血脈性躺在上面

    退避在頸動脈vessels.(12) 理論上,

    承購更加準確的時間與這樣熱忱

    k 空間裝填設計也許允許對a 的用途

    降低對比媒介的劑量。釓是

    一個昂貴的對比媒介為MRI, 如果劑量

    可能被減少, 它會幫助切開費用的

    MRI 考試。這項研究的目標是

    確定中心技術的可行性

    使用釓唯一藥量在估計

    extracranial 頸動脈和椎骨動脈系統。

    方法

    從6月通過2004 年8月, 44 連貫

    患者(25 個人, 19 名婦女; 年齡範圍, 40-78 年;

    平均年齡, 61.3 9.1 年) 與建議的腦血管

    疾病被提到了為先生angiographic

    評估extracranial 頸動脈和

    椎骨動脈。患者的平均重量是

    71.8 9.3 公斤(範圍, 54-86 公斤) 。所有患者是

    最初地評估使用雙重ultrasonography

    (美國) 為頸動脈循環。表1 顯示

    基本的特徵和患者的美國研究結果。

    想像先生執行了使用1.5T 先生

    掃描器(Intera; Philips 醫療系統, 最佳,

    荷蘭) 以一個最大的可達成的梯度

    高度30 mT/m, 0.2 毫秒的日出時間, 和a

    150 T/m/sec 的沼澤率。一商業可利用

    phased-array 卷(共同作用頭和脖子卷;

    能的Philips 醫療系統, 荷蘭)

    報道頭、脖子, 和上部胸口的地區

    被使用了。在安置患者之前, 20 測量

    靜脈內導尿管被安置了在antecubital

    靜脈。

    各名患者任意地被分配了入一

    二個小組關於相當數量釓

    螯合射入(Omniscan; Nycomed, 奧斯陸,

    挪威): 編組1 (n = 22) 被接受的雙重藥量

    釓0.2 mmol/kg 和小組2 (n = 22)

    0.1 mmol/kg 被接受的唯一藥量。對比

    媒介被注射了以2 ml/sec 的率, 被跟隨

    由注滿以10 機器語言鹽解答在同樣

    率使用一個先生兼容力量注射器

    (Optistar; Mallinckrodt Inc., 俄亥俄, 美國) 。Contrastenhanced

    三維(3D) MRA 是trigged

    由二維實時先生fluoroscopy 在

    花冠plane.(14) 當先生fluoroscopy 顯露

    對比材料一小團的到來在左邊

    心房, angiographic 脈衝序列開始了

    以4 秒延遲。先生的協議

    fluoroscopy 是作為以下: TR/TE/Flip

    角度= 3.4 ms/1.0 ms/40., 視野450

    表1 。研究人口的基本的特徵

    小組1 (N = 22) 小組2 (N = 22)

    0.2 mmol/kg 0.1 mmol/kg p 價值*

    年齡(年) 62.8 9.4 59.8 8.7 0.29

    體重(公斤) 72.3 8.9 71.3 9.4 0.74

    心率(beat/min) 74.6 6.4 71.9 7.3 0.20

    釓(機器語言) 平均總藥量28.9 3.6 14.3 1.9

    雙重ultrasonography 研究結果

    法線11 (50%) 12 (55%)

    溫和或適度狹窄? 9 (41%) 7 (31%)

    嚴厲狹窄或鎖柱? 2 (9%) 3 (14%)

    * 二樣品t 測試

    ? 狹窄或鎖柱被懷疑在一個或更多比一個船

    supraaortic 動脈。

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    毫米、10 毫米的部分厚度, 和圖像

    承購率的1 秒。

    angiographic 先生序列執行了

    使用任意地被分割的中央kspace 技術

    定貨以中心著名。參量

    中心是如下: 3D 梯度echo

    序列與4.6/1.67, 40. 輕碰角度, 長方形

    視野50%, 圖像矩陣416

    416 在300 毫米視野與120 分開

    0.7 毫米。總承購時間是58 秒。A

    唯一被減去的3D 想像由減去計算了

    unenhanced 集合從改進的集合。

    最大強度投射重建

    被減去的圖像引起了從唯一分開

    (九投射在20. 增加在a 之內

    180. 自轉) 。所有研究由進行了

    唯一先生想像技術員。

    為定量評估, 卑鄙信號

    船流明的強度(SIV) 在七

    地區利益, 包括brachiocephalic

    動脈, 雙邊頸動脈叉路(正確和左),

    雙邊顱內的內部頸動脈, 和

    雙邊椎骨動脈, 和¥L們圍攏

    組織(SIB), 被測量了(圖1) 。圖像噪聲

    () 被測量了作為標準偏差從

    發信號空氣的強度圍攏患者。

    對比對噪聲比率(CNR) 各個區域

    興趣被計算了使用以下慣例:

    CNR = (SIV - SIB)/ 。

    為定性評估, 圖像是

    回顧盲目的時尚由二位調查員

    誰分開地回顧了圖像先生在被隨機化

    指令為計分描述九血管

    地區(brachiocephalic 動脈, 共同頸動脈

    動脈, 內部頸動脈, 外在頸動脈

    動脈, 椎骨動脈, 基部的動脈, 中間大腦

    動脈、先前大腦動脈和後部

    大腦動脈) 和程度多血脈性的覆蓋物。

    等級量表為描述九血管

    地區是如下: (1) 優秀描述

    動脈流明和鋒利的邊緣; (2) 好描述

    動脈流明以一溫和弄髒

    邊緣; (3) 動脈流明的公正的描述

    以引人注目弄髒邊緣; (4) 粗劣的描述

    動脈流明以一主要邊緣弄髒;

    並且(5) 不可評價。等級量表為

    多血脈性的覆蓋物是如下: (1) 內部頸靜脈

    靜脈不可看見; (2) 內部頸部的靜脈幾乎沒有可看見;

    (3) 引人注目的信號強度在內部頸靜脈裡

    靜脈; (4) 可比較的信號強度在內部頸靜脈裡

    靜脈和內部頸動脈; 並且(5) 更加偉大

    信號強度在內部頸部的靜脈裡比在內部

    頸動脈。

    統計分析執行了使用擅長

    軟體(微軟, 西雅圖, 華盛頓州, 美國) 使用

    圖1 最大強度投射圖像的頸動脈

    血管學以中心技術, 顯示先生

    七個地區利益(黑空白的圈子) 在brachiocephalic

    動脈, 雙邊頸動脈叉路, 雙邊

    顱內的內部頸動脈, 和雙邊椎骨

    動脈。

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    two-tailed 學生t 測試。p 價值少於0.05

    被認為一個統計地重大區別。

    所有價值被提出了作為手段SDs 。

    程度協議在觀察員之間是堅定的

    使用統計。協議被分類了

    像適度(= 0.40-0.69), 好(= 0.70-

    0.89), 或優秀(= 0.90-1.00) 。

    結果

    所有我們的患者很好容忍了規程。

    沒有在年齡上的重大區別, 身體

    重量和心率在二個小組之間

    患者(p > 0.05) 。做法近似地持續了

    30 分鐘為各名患者, 包括所有

    定期想像先生和MRA 考試。

    CNRs 的定量評估結果

    七個地區被顯示在表2 。為brachiocephalic

    動脈, CNRs 在小組1 極大是

    更加高級比那些在小組2 (p = 0.015) 。為

    雙邊頸動脈叉路, 雙邊顱內

    內部頸動脈和雙邊椎骨動脈,

    沒有統計地重大區別

    在CNR 在這兩個小組之間(p > 0.05) 。

    定性規定值為描述九

    船和多血脈性重疊二個小組

    被總結在表3 。brachiocephalic

    動脈, 共同的頸動脈, 內部頸動脈

    動脈, 外在頸動脈, 椎骨動脈

    是可看見的在所有研究。船的零件是

    不可看見在計分期間由於嚴厲

    狹窄或鎖柱。基部的動脈是可看見的

    在41 (93%) 44 名患者中。中部大腦

    動脈是可看見的在80 (91%) 88 讀書中。

    先前大腦動脈是可看見的在76

    (86%) 88 讀書。後部大腦

    動脈是可看見的在82 (93%) 88 讀書中。

    內部頸部的靜脈沒被看見或是正義的

    幾乎沒有可看見在66 (75%) 88 讀書中。那裡

    之間不是統計地重大區別

    這兩個小組(p > 0.05) 為這樣定性評估。

    Interobserver 協議為所有評估

    好或優秀, (範圍, 0.84 - 0.95) 。

    討論

    對比改進的MRA 越來越是

    使用在頸動脈想像在過去幾個

    years.(6-8,15,16) 對比材料的靜脈內射入

    在一小團方式引起一個更強的信號在

    專利船以更好的背景鎮壓

    更短的考試時光比其它射入技術。

    但是, 重疊頸部的靜脈

    頸動脈叉路是一個扼要

    缺點。最近, 中心k 空間定貨

    技術卓越地改進了質量

    頸動脈的對比改進的MRA,

    造成高空間決議和充足

    多血脈性suppression.(13,17) 在常規橢圓中心

    觀看定貨的技術, 樣品在

    階段內碼方向被重新安排以便

    資料在k 空間的中心首先被獲取。它是

    關鍵以這個技術, 第一看法對應

    以一小團峰頂。所以, 計時

    表2 。7 地區的CNRs 利益以2 不同藥量

    釓注射了

    CNR

    ROI 編組1 個小組2 p 價值

    (0.2 mmol/kg) (0.1 mmol/kg)

    Brachiocephalic 動脈91.36 6.64 86.82 5.12 0.015

    左CCA 87.68 6.68 89.82 7.88 0.338

    正確的CCA 87.27 5.51 89.05 7.93 0.394

    左顱內內部

    頸動脈89.36 5.76 87.14 4.81 0.171

    正確顱內內部

    頸動脈90.45 8.31 88.50 7.75 0.424

    左椎骨動脈87.68 7.18 84.77 7.45 0.194

    正確的椎骨動脈87.25 7.89 85.18 8.13 0.392

    簡稱: CNR: 對比吵鬧比率; ROI: 區域利益;

    CCA: 共同的頸動脈。

    表3 。定性評估卑鄙比分比較在2 個小組中

    比分

    小組1 個小組2 p 價值

    (0.2 mmol/kg) (0.1 mmol/kg)

    動脈形象化

    Brachiocephalic (N = 44) 2.2 0.7 2.5 0.8 0.069

    共同頸動脈(N = 88) 1.7 0.7 1.6 0.7 0.534

    內部頸動脈(N = 88) 1.8 0.6 2.0 0.7 0.318

    外在頸動脈(N = 88) 2.0 0.9 2.2 1.0 0.248

    椎骨(N = 88) 2.7 0.9 2.4 0.8 0.123

    基部(N = 41) 2.5 0.7 2.3 0.8 0.255

    中間大腦(N = 80) 2.6 0.7 2.8 0.9 0.277

    先前大腦(N = 76) 3.2 0.8 3.6 1.1 0.099

    後部大腦(N = 82) 3.5 0.9 3.7 1.0 0.242

    多血脈性的覆蓋物(N = 44) 2.2 0.9 1.9 0.8 0.090

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    對比媒介一小團峰頂是重要, 然而, 空間的

    決議和覆蓋面仍然被限制。

    在這項研究, 我們使用了中心技術

    解決主要弱點常規橢圓

    中心看法定貨的技術。中心

    任意地獲取資料在中央區段在期間

    充分的動脈階段, 因此第一看法沒有

    對應以一小團峰頂。在資料以後有

    被獲取在對比確定的中央

    k 空間的盤, 承購資料可能延伸

    很好在一小團的實際動脈段落之外,

    以動脈階段圖像對比的保存。

    從可利用的承購時間是長的, 那裡是

    充足的時刻為採樣資料為高想像

    矩陣。在我們的患者, 我們使用了承購

    產生矩陣大小的416 58 秒的時期

    416. 這給更高的空間決議被比較

    以常規橢圓定貨的技術

    (176 256 矩陣在20 秒承購

    time).(17,18)

    據我們所知, 少量researchers(12,13,19) 有

    演講了釓劑量的影響

    頸動脈MRA 的圖像質量以中央kspace

    定貨的技術。多數可利用

    臨床研究報告了有為的結果

    頸動脈MRA 以釓的固定的容量

    排列在20-25 ml.(6,15,20,21) Luccichenti 和al.(19) 之間

    使用省略地被定□的序列執行

    MRA 和聲稱優選的圖像質量會

    被獲得以釓藥量大於0.16

    體重mmol/kg 在頸動脈船。

    中心技術應用第一次被調查了

    由Willnek 和al.(12) 他們認為, 中心

    是對比提高的一個健壯技術

    3D MRA 和產生的優質診斷圖像

    在患者被建議有腦血管的疾病。

    在他們的研究中, 雙重藥量(0.2 mmol/kg)

    釓射入被使用了。

    我們的結果顯示了那圖像質量

    血管學先生在頸動脈使用中心

    技術以唯一藥量(0.1 mmol/kg)

    釓是可相比較和那被獲得使用

    雙重藥量(0.2 mmol/kg) 定量地兩個和

    定性地。brachiocephalic 動脈CNR

    雙重藥量小組比那高級在

    藥量小組。這也許歸結於被加寬

    brachiocephalic 動脈的流明, 造成

    對釓的血管內的集中的減少

    在single-dose 小組在資料採集期間。

    但是, 這沒有影響描述

    brachiocephalic 動脈因為沒有重大的

    區別在二個小組之間在定性

    這艘船的評估。

    另外, 我們使用了fluoroscopic 監視

    對比到來在頸動脈觸發圖像

    承購以便動脈階段可能有選擇性地是

    印象和多血脈性重疊可能是

    減少。觸發的方法可能提供全面

    頸動脈的評估包括

    所有船段從大動脈曲拱對

    圈子Willis.(20,22) 然而, 這的成功

    技術依靠操作員的經驗。

    所以, 在我們的研究, 所有掃瞄執行了

    由一位唯一技術員為了避免這樣的interoperator

    變異。我們的結果沒有顯示重大

    區別在二個小組之間在評估

    多血脈性重疊。進一步研究是

    要求調查可靠性fluoroscopic

    觸發技術在不同的操作員之中。

    對比改進的MRA 準確性為

    頸動脈疾病的評估被確認了

    由幾investigators.(6,19,22) 在我們的研究中, 然而,

    我們比較了二個小組的想像質量

    使用對比媒介不同的藥量但我們

    不估計他們對應的準確性在疾病

    評估。這是因為無我們的患者

    接受了導尿管血管學。進一步臨床

    研究必需估計診斷準確性

    中心技術以被減少的劑量

    對比媒介射入。

    總而言之, 這項研究的結果建議

    那以對中心技術的用途, 對比

    頸動脈改進的MRA 使用唯一

    藥量對比媒介也許提供可比較

    圖像質量對那使用雙重藥量。

    參考

    1. Borisch I, 墊鐵M, Butz B, Zorger N, Draganski B,

    Hoelscher T, Bogdahn U, 鏈接J. Preoperative 評估

    頸動脈狹窄: 比較contrastenhanced

    sonography 先生血管學和雙重與

    數字式減法血管學。AJNR 上午J Neuroradiol

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  • 1 decade ago

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