A comparison between dynamic pelvic magnetic resonance imaging and videoproctography in patients with constipation

PURPOSE: This study attempts to compare the diagnostic efficacy of dynamic pelvic magnetic resonance imaging with that of videoproctography for the presence of rectocele, sigmoidocele, and intussusception as well as the measurement of anorectal angle and perineal descent in constipated patients. METHODS: Patients volunteering for the study and fulfilling the criteria for videoproctography to evaluate constipation were also scheduled for dynamic pelvic magnetic resonance imaging. Patients undergoing videoproctography were placed in the left lateral decubitus position, after which 50 ml of liquid barium paste was introduced into the rectum. After this, approximately 100 ml of thick barium paste similar to stool in consistency was injected into the rectum, and the patient was instructed to defecate while video images were taken. For dynamic pelvic magnetic resonance imaging, air, to be used as contrast, was allowed to accumulate in the rectumvia examination with the patient in the prone position. A capsule was taped to the perineal skin immediately posterior to the anal orifice for marking. Sagittal and axial T1 images were obtained through the pelvis at 8-mm intervals with dynamic breathhold sagittal images of the anorectal region obtained at rest and during strain and squeeze maneuvers. Total acquisition time per maneuver was approximately 19 seconds. The tests were performed by different examiners blinded to the result of the other evaluation. The investigations were independently interpreted, findings compared, and patients questioned regarding their impression of dynamic pelvic magnetic resonance imaging and videoproctography. RESULTS: From June 1996 to April 1997, 22 patients (15 females) with a mean age of 68 (range, 21–85) years underwent both videoproctography and dynamic pelvic magnetic resonance imaging. Dynamic pelvic magnetic resonance imaging was only able to detect 1 of 12 (8.3 percent) anterior rectoceles and one of two (50 percent) posterior rectoceles identified by videoproctography. It failed to recognize any of the rectoanal intussusception (zero of four) but did show 9 of 12 (75 percent) sigmoidoceles. Significant discrepancy of measurement of the anorectal angle and perineal descent exists between the two studies, and dynamic pelvic magnetic resonance imaging was not able to detect any (0 of 11) of the patients with increased fixed perineal descent and only half (one of two) of the patients with increased dynamic perineal descent noted on videoproctography. All 22 patients preferred dynamic pelvic magnetic resonance imaging over videoproctography because of greater comfort. CONCLUSION: Occasionally, the increased cost of new technology can be justified by the enhanced diagnostic yield. The ability to avoid unnecessary surgery or, conversely, to continue to search for otherwise occult pathology that can be surgically corrected justifies routine application of these new tools. However, this study has shown that, despite a cost of approximately ten times more for dynamic pelvic magnetic resonance imaging than for videoproctography, no clinical changes were made. Thus, on the basis of this study, we cannot endorse the routine application of dynamic pelvic magnetic resonance imaging for the evaluation of constipated patients. In certain selected individuals, it may play a role, but further study is necessary to clarify its exact role.Supported in part by a generous educational grant from the Caporella family.     

血管壁磁共振成像在老年颈动脉粥样硬化患者术前评估中的应用

目的 探讨磁共振成像(MRI)对老年颈动脉粥样硬化患者术前评估的应用价值及序列优化.方法 70例老年缺血性脑血管疾病的患者,超声检查发现颈动脉分叉处有斑块,分别进行颈动脉MRI和数字减影血管造影(DSA)检查.颈动脉MRI检查序列包括平扫及增强T1加权(T1W1)、T2加权、质子加权(PDWI)和3D时间飞跃法MR血管成像(3D-TOF MRA).扫描完成后将图像分为两种序列组合,即5序列组合(上述5个序列)和2序列组合(T1WI和3D TOF)MRI图像.DSA检查摄取颅外段颈动脉常规正位及侧位图像.分析MRI与DSA之间、MRI不同序列组合之间对管腔狭窄和纤维帽破溃的检出差异.结果 70例患者中1例图像质量较差,余69例中除3支血管为支架置入术后,共135支血管.5序列及2序列MRI组合检测的平均管腔狭窄程度分别为(38.3±31.0)%和(38.5±30.9)%,差异无统计学意义(t=2.447,P＞0.05).DSA检测的平均血管狭窄程度为(35.1±31.8)%,以其作为金标准,MRI两种序列组合与金标准间具有很好的一致性(Kappa值0.773).两种序列组合分别检出36支血管具有溃疡斑块,差异无统计学意义;DSA检出16支血管具有溃疡斑块,MRI与DSA检出溃疡斑块的差异有统计学意义(χ2=12.0,P＜0.01).结论 MRI可以准确判断颈动脉的管腔狭窄程度并检出溃疡斑块的存在,通过对扫描序列的优化可以有效减少检查时间,是老年颈动脉粥样硬化患者术前评估的较好的检查手段.

Abstract：

Objective To study the value of carotid plaque magnetic resonance imaging (MRI) in pre-operation assessment in the elderly patients with carotid atherosclerosis and explore the possibility of minimizing the contrast weightings to gain sweeptime. Methods Totally 70 elderly patients with cerebral ischemia (average age of 68.8 years) underwent carotid MRI and digital subtraction angiography (DSA) due to the appearance of carotid plaque detected by ultrasound. Carotid plaque MRI was acquired with 3.0T MR scanner and 8 channel surface coil. The standard carotid plague MRI program included pre-and post-contrast T1 weighted imaging (T1WI), T2 weighted imaging, proton density weighted imaging and 3D time of flight MR angiography (3D TOF MRA). All these program were divided into two combinations: the 5-sequence MRI (all the sequences) and 2-sequence MRI (T1WI and TOF MRA). Digital subtraction angiography (DSA) in coronal and lateral views of carotid artery was performed with GE Advantx LCN+. The software SPSS 13.0 was used to statistically analyze the difference between MRI and DSA, and that of two sequence combinations was used in the detection of luminal stenosis and fibrous cap (FC) rupture. Results Totally 135 arteries were analyzed while 3 arteries in one patient were excluded due to the poor quality image and stent placement. The degree of luminal stenosis were (38.3±31.0)% and (38.5±30.9)%, respectively, detected by the two MRI sequence-combination with no significant difference (t=2.447, P＞0.05) and was (35.1±31.8)% by DSA. There was a good concordance between MRI and DSA in luminal stenosis detection (Kappa value: 0.773). No statistical difference was found between two MR sequence combinations in detecting FC rupture (both in 36 vessels). DSA detected FC rupture of 16 vessels, showing remarkably difference contrast to MRI(χ2=12.0, P＜0.01). Conclusions MRI can accurately detect the luminal stenosis and FC rupture. The short time scanning resulting from sequence optimization could make MRI much more suitable than DSA to do the pre-operation assessment for senile carotid atherosclerotic patients.     

有症状颈动脉狭窄患者颈动脉斑块的稳定性:高分辨率磁共振成像研究

目的 探讨高分辨率磁共振成像(high-resolution magnetic resonance inaging,HR-MRI)评价有症状颈动脉狭窄患者斑块稳定性的价值以及不稳定斑块和血管重度狭窄的危险因素.方法 纳入有症状颈动脉狭窄患者,通过HR-MRI评价有症状颈动脉狭窄患者颈动脉斑块成分判断斑块的稳定性.收集行颈动脉内膜切除术患者的颈动脉斑块进行病理学检查,比较术前HR-MRI与术后病 理学检查结果的一致性.收集所有患者的临床资料,分析颈动脉斑块稳定性和血管狭窄程度的危险因素.结果 共219例狭窄程度＞50％的有症状颈动脉狭窄患者接受HR-MRI检查.其中102例(46.6％)存在稳定斑块,117例(53.4％)患者存在不稳定斑块;118例(53.9％)中度狭窄,101例(46.1％)重度狭窄.35例患者接受颈动脉内膜切除术,其中19例(54.3％) HR-MRI显示斑块不稳定,20例(57.1％)病理学检查显示斑块不稳定,二者高度一致(κ =0.942,P＜0.001).不稳定斑块组男性(P=0.007)、高脂血症(P=0.013)、吸烟(P＜0.001)的患者构成比以及总胆固醇(P=0.001)、低密度脂蛋白胆固醇(P＜0.001)和空腹血糖(P=0.001)水平显著高于稳定斑块组.多变量logistw 回归分析显示,男性[优势比(odds ratio,OR)2.33,95％可信区间(confidence interval,CI) 1.08 ～ 5.04;P=0.032]、吸烟(OR 3.45,95％ CI 1.67～7.14;P=0.001)和空腹血糖水平较高(OR 1.26,95％ CI 1.07～1.48;P =0.006)是斑块不稳定的独立危险因素.中度狭窄组与重度狭窄组患者的所有资料均未显示出显著性差异.结论 HR-MRI能准确评估有症状颈动脉狭窄患者的斑块稳定性.性别、吸烟和空腹血糖增高是颈动脉不稳定斑块的独立危险因素.     

Head-to-head comparison between contrast-enhanced magnetic resonance imaging and dobutamine magnetic resonance imaging in men with ischemic cardiomyopathy

Contrast-enhanced magnetic resonance imaging (MRI) can predict functional recovery after revascularization. Segments with small, subendocardial scars have a large likelihood of recovery, and segments with transmural infarction have a small likelihood of recovery. Segments with an intermediate extent of infarction have an intermediate likelihood of recovery, and therefore, additional information is needed. Accordingly, the transmurality of infarction on contrast-enhanced MRI was compared with low-dose dobutamine MRI to further define viability in 48 patients. Regional contractile dysfunction was determined by cine MRI at rest (17-segment model), and contractile reserve was determined using low-dose dobutamine infusion. Contrast-enhanced MRI was performed to assess the extent of scar tissue. A total of 338 segments (41%) were dysfunctional, with 61% having contractile reserve. Most segments (approximately 75%) with small, subendocardial scars (hyperenhancement scores 1 or 2) had contractile reserve, whereas contractile reserve was not frequently (17%) observed in segments with transmural infarction (hyperenhancement score 4) (p <0.05). Of segments with an intermediate infarct transmurality (hyperenhancement score 3), contractile reserve was observed in 42%, whereas 58% did not have contractile reserve. In conclusion, the agreement between contrast-enhanced MRI and low-dose dobutamine MRI is large in the extremes (subendocardial scars and transmural scars), and contrast-enhanced MRI may be sufficient to assess the likelihood of the recovery of function after revascularization. However, 61% of segments with an intermediate extent of scar tissue on MRI have contractile reserve and 39% lack contractile reserve. In these segments, low-dose dobutamine MRI may be needed to optimally differentiate myocardium with large and small likelihoods of functional recovery after revascularization.     

A preliminary study on the application of high-resolution magnetic resonance vessel wall imaging in the evaluation of intracranial aneurysms

<正>Objective The present study ws to investigate the feasibility of use of high resolution magnetic resonance vessel wall imaging(HR-VWI)in evaluation of intracranial aneurysms.Methods We prospectively collected data from patients who had intracranial aneurysms and received HR-VWI scan before surgical treatment or conservative treatment.Aneurysms were divided into ruptured     

Relationship between mitral annular calcification and severity of carotid atherosclerosis in patients with symptomatic ischemic cerebrovascular disease

OBJECTIVES: Many studies have reported the association between mitral annular calcification (MAC) and stroke. MAC has been speculated to be a direct embolic source of stroke. Recently, the association between MAC and atherosclerosis in the coronary artery, aorta, and carotid artery has been reported. This prospective study investigated the association between MAC and severity of carotid atherosclerosis in patients with symptomatic ischemic cerebral disease to evaluate the association between MAC and atherosclerosis as a cause of stroke. METHODS: We studied 377 patients with ischemic cerebral disease (253 men, 124 women, mean age 68 +/- 11 years) who underwent echocardiography to determine the presence of MAC and carotid ultrasonography to determine the severity of carotid atherosclerosis. Plaque score was the sum of the maximum intimamedia thickness in the common carotid region, the bifurcation bulb region, and the internal carotid artery region, including both right and left arteries. RESULTS: MAC was found in 86 patients, and was more frequent in women, the elderly, and patients with diabetes or hyperlipidemia (p < 0.05). Plaque score was higher in patients with than without MAC (8.3 +/- 5.8 vs 5.2 +/- 5.2 mm, p < 0.001). Multivariate regression analysis identified MAC (r = 0.26, p < 0.0001), female sex (r = -0.12, p = 0.03), and age (r = 0.23, p < 0.0001) as independently associated with plaque score. CONCLUSIONS: MAC is independently associated with severity of carotid atherosclerosis in patients with symptomatic ischemic cerebral disease. This association suggests MAC may be indirectly related to cerebrovascular disease as a marker of the presence of progressive arteriosclerosis for thromboemboli causing stroke.     

磁共振灌注检查在老年颈动脉狭窄患者支架置入术中的应用

目的探讨磁共振灌注加权成像(perfusion-weighted imaging,PWI)检查在老年颈动脉狭窄患者支架置入术(carotid artery stenting,CAS)中的应用。方法选择15例年龄≥70岁的症状性颈动脉狭窄患者行CAS,在术前及术后72h分别行PWI检查,对比手术前后影像的改变,并与相关CT灌注成像研究结果进行对比。结果 15例患者全部成功实行CAS,术前PWI异常的患者在术后均有不同程度的改变,差异有统计学意义(P<0.01);术前PWI正常的患者在术后无变化。手术前后脑血流循环时间比较,差异有统计学意义(P<0.01)。结论 PWI检查在症状性颈动脉狭窄患者CAS前后有明显改变,其结果与相关CT灌注研究相符。     

Aortic root asymmetry in Marfan patients; evaluation by magnetic resonance imaging and comparison with standard echocardiography

Background: Patients with Marfan syndrome may develop aortic root dissection despite only mild aortic root dilation as shown by standard echocardiography, which may be due to aortic root asymmetry. Purpose of the present study was to investigate aortic root asymmetry by magnetic resonance (MR) imaging in patients with Marfan syndrome and to compare these measurements with standardly performed echocardiography. Methods: Eighty-seven Marfan patients (mean age 31 ± 8 years) underwent MR imaging. From this population, 15 patients (mean age 29 ± 3 years) were selected in whom both echocardiography and MR imaging had been performed within 3 months. With echocardiography, the aortic root was measured according to the recommendations of the American Society of Echocardiography. With MR imaging, a short axis view of the aortic root was obtained to measure distances between the noncoronary, right coronary and left coronary cusps and the aortic root area. Correlations between aortic root area and diameters were assessed, and 95% confidence intervals (95% CIs) calculated. Results: No difference in the standardly measured noncoronary to right coronary cusp diameter between MR imaging and echocardiography was shown (42 ± 6 mm). Largest aortic root diameter on the MR images was the right to left coronary cusp diameter (46 ± 7 mm, p < 0.02). For a given noncoronary to right coronary cusp diameter, 95% confidence intervals revealed a variation of –20 to +20% in the aortic root area. Conclusions: The majority of Marfan patients show asymmetric dilation of the aortic root by MR imaging. This phenomenon may go unnoticed when standard echocardiography is performed. The asymmetry of the aortic root might be of clinical importance in unexpected aortic root dissection.     

中老年人动脉粥样硬化斑块的磁共振成像

动脉粥样硬化斑块 (atheroscle roticplaque)是中老年人最常见的心血管疾病 ,目前磁共振成像 (mag neticresonanceimaging ,MRI)是显示动脉粥样硬化斑块最有前途的非创伤性检查方法。近年来动物实验和临床研究结果表明 ,MRI能显示主动脉、颈动脉甚至冠状动脉粥样硬化斑块的位置、厚度及其成分 ,并对治疗后疗效随访亦有较大帮助。1　动脉粥样硬化斑块的病理动脉粥样硬化是发生在中老年人主动脉、颈动脉及冠状动脉等血管壁上一种常见疾病[1] ,其病理成分包括 :①细胞外基质的结缔组织(胶原糖蛋白、纤维素及弹力纤维 ) ;②胆固醇结晶、胆固…     

老年患者股动脉和颈动脉及冠状动脉粥样硬化斑块稳定性的比较

目的　探讨股动脉、颈动脉、冠状动脉粥样硬化斑块的稳定性。方法　收集我院老年尸体解剖病例 15例 ,将所有病例的两侧股动脉、两侧颈动脉、左冠状动脉前降支进行连续取材 ,常规病理检查 ,部分节段行α 平滑肌肌动蛋白、CD6 8、bax染色。结果　股动脉粥样硬化斑块中的平滑肌细胞、巨噬细胞数量与颈动脉相近。与冠状动脉比较 ,股动脉粥样硬化斑块中的平滑肌细胞相对多 ,巨噬细胞相对少 ;bax在巨噬细胞的表达多 ,在平滑肌细胞的表达少。结论　平滑肌细胞、巨噬细胞数量的不同导致了 3种动脉粥样硬化斑块不同的稳定性。股动脉中的粥样硬化斑块较冠状动脉更稳定。     

Transesophageal magnetic resonance imaging of the aortic arch and descending thoracic aorta in patients with aortic atherosclerosis

OBJECTIVES

We sought to determine the feasibility and potential of transesophageal magnetic resonance imaging (TEMRI) for quantifying atherosclerotic plaque burden in the aortic arch and descending thoracic aorta in comparison with transesophageal echocardiography (TEE).

BACKGROUND

Improved morphologic assessment of atherosclerotic plaque features in vivo is of interest because of the potential for improved understanding of the pathophysiology of plaque vulnerability to rupture and progression to clinical events. Magnetic resonance imaging (MRI) is well suited for atherosclerotic plaque imaging. Performing MRI using a radio frequency (RF) receiver probe placed near the region of interest improves the signal-to-noise ratio (SNR).

METHODS

High-resolution images of the thoracic aortic wall were obtained by TEMRI in 22 subjects (8 normals, 14 with aortic atherosclerosis). In nine subjects, we compared aortic wall thickness and circumferential extent of atherosclerotic plaque measured by TEMRI versus TEE using a Bland-Altman analysis. Additional studies were performed in a human cadaver with pathology as an independent gold standard for assessment of atherosclerosis.

RESULTS

In clinical and experimental studies, we found similar measurements for aortic plaque thickness but a relative underestimation of circumferential extent of atherosclerosis by TEE (p = 0.001), due in large part to the lower SNR in the near field.

CONCLUSIONS

Using TEMRI allows for quantitative assessment of thoracic aortic atherosclerotic plaque burden. This technique provides good SNR in the near field, which makes it a promising approach for detailed characterization of aortic plaque burden.     

Thyroid volume measurement in patients prior to radioiodine therapy: comparison between three-dimensional magnetic resonance imaging and ultrasonography.

Because of its cost effectiveness, wide availability, and technical ease of application, ultrasonography is the reference method for determining the thyroid volume prior to radioiodine therapy. The goal of the study is a prospective assessment of the deviation between volumetric ultrasonography measurements in comparison to those performed with three-dimensional magnetic resonance imaging (MRI). To that end, 60 consecutive patients with multinodular toxic goiter (n = 28, 46.7%) or Graves' disease (n = 32, 53.3%) were included in the study. Ultrasonographic volumetry according to the well-known ellipsoid formula was performed by three different technicians. In addition, three-dimensional MRI scans of the neck area were acquired and evaluated by the ellipsoid formula as well as by a dedicated region-of-interest technique (MRI-ROI), which was used as standard of reference. While there was no significant difference between the ultrasonographic examinations of the three technicians, a highly significant mean deviation of 22.7% (10.4 mL) was found between the sonographic measurements and the MRI-ROI results (p < 0.01) that were underestimated in 80% of the cases. Correlation coefficients between the various volumetric approaches were highly significant, with values of at least 0.886 (p < 0.01). An additional analysis of volume-dependent subgroups revealed that thyroid volume had no significant influence on the results of ultrasonographic volumetry (p > 0.15). In conclusion, the study showed ultrasonography to be a reliable method of satisfactory accuracy that is appropriate for volumetric thyroid measurements. The findings indicate that the use of a correction factor higher than 0.52 in the ellipsoid formula is recommended to improve accuracy. However, further studies are necessary to confirm these findings.