CT评估正常通气猪肺射频与微波消融效果的研究

【摘要】目的：采用CT评估正常通气猪肺射频与微波消融的效果。方法：健康家猪6只,每侧肺各布置两个消融区,在CT引导下左肺行经皮射频消融,右肺行经皮微波消融,共消融10min,消融过程中每分钟进行1次CT扫描,获得不同时间点消融灶的图像。测量并比较各不同消融方法及不同时间点消融灶的最大纵径、最大横径、横截面积、体积和横纵径比。结果：时间与消融方式均会对消融灶的大小产生影响（P＜0.05）。在各个时间点上,微波消融灶的最大纵径、最大横径、横截面积、体积均大于射频。消融10min后,射频与微波消融灶的最大纵径分别为（4.23±0.35）cm、（5.34±0.39）cm,最大横径分别为（3.09±0.18）cm、（3.83±0.44）cm,消融灶横截面积S分别为（10.27±1.24）cm2和（16.15±2.79）cm2,体积V分别为（21.25±3.60）cm3和（41.96±12.02）cm3,差异均具有统计学意义（P＜0.001）。结论：微波和射频均是安全的微〖JP2〗创疗法,在正常通气肺组织中的消融范围及形状存在一定差异,了解其特性有利于两种技术的合理应用。     

应用64层螺旋CT探讨脾体积的简易估测方法

目的 运用64层螺旋CT测量成人正常脾体积(splenic volume,SP)及容积相关参数,探讨SP与生理参数的关系及SP的简易估测方法.资料与方法 对无明确脾疾病的120例受检者行64层螺旋CT腹部增强扫描,针对层厚2 mm、重组间隔2 mm的门静脉期图像进行分析.采用Siemens Volume体积测量软件测定脾的体积值,并测定脾上下径、左右径、前后径、厚度和最大截面积.对测量结果进行统计分析.结果 120例受检者的平均脾体积为(203±79)cm3.平均脾上下径、左右径、前后径、厚度和最大截面积分别为(9.0±1.7)cm、(9.1±1.0)cm、(9.5±1.9)cm、(3.8±0.7)cm和(35.6±9.5)cm2.体积与身高、体重存在较弱的正相关关系,与年龄间存在较弱的负相关关系.消除了体重因素的影响后,不同性别组间SP无显著差异.SP与脾上下径(r=0.7887,P＜0.01)及脾最大截面积(r=0.8641,P＜0.01)均具有很好的正相关性.简化的回归方程为:脾体积=0.616×脾上下径×脾最大截面积(t=109.7,r2=0.9906,P＜0.01).脾增大的诊断标准为SP＞358 cm3.结论 SP与各种生理参数间相关性不强,绝对体积值＞358 cm3可诊断为脾增大.通过测量CT像上脾上下径与最大横截面积,可以简单、迅速而较准确地估测SP.     

正常肝、脾体积与多种生理参数的相关性研究

目的 分析正常肝、脾体积,脾/肝体积比及其与性别、年龄、身高、体重、体重指数(body mass index,BMI)的相关性,为临床研究慢性肝病的肝、脾体积提供更有价值的定量指标.方法 收集正常志愿者或其他原因行上腹部CT检查的肝、脾正常者230例(男110例、女120例,年龄20～70岁,平均45.77岁),检查前测量其身高和体重并计算出BMI,采用GE LightSpeed 64 VCT XT机,以螺旋扫描方式行上腹部平扫及增强检查,然后在增强门脉期0.625 mm薄层扫描图像上,采用该CT机的容积测量软件对肝、脾体积进行定量研究,计算出脾/肝体积比,并与性别、年龄、身高、体重、BMI进行相关性分析.结果 本组研究对象的平均肝脏容积为(1 153.50±237.78)cm3,其中男(1 256.10±237.44)cm3、女(1 059.50±196.29)cm3;脾脏大小:(156.38±58.93) cm3,其中男(173.26±60.68)cm3、女(140.91±52.97)cm3;脾/肝体积比为0.136±0.047.不同性别之间的肝、脾容积大小均有统计学差异(P=0.000),脾/肝体积比则无显著差异(t=1.008,P=0.314).肝、脾大小及脾/肝体积比与年龄均无显著相关性.肝、脾体积与身高、体重及BMI的相关系数r分别为:0.438、0.662、0.524,0.308、0.333、0.321(均为P=0.000),表现为中度正相关;脾/肝体积比则与上述因素均无显著相关(P＞0.05).结论 临床研究肝、脾容积大小时,需充分考虑到性别、身高、体重等因素的影响;脾/肝体积比不受个体生理参数的影响,可作为一个评价肝储备功能和判断肝硬化程度的更有价值的定量指标.     

兰州地区成人脾脏容积多层螺旋CT测量

目的:探讨正常成人脾脏容积多层螺旋CT测量的方法和正常值,并研究脾脏容积与脾脏各径线长度及肋单元的相关性。方法:应用多层螺旋CT自带的Volume软件对400例正常成人脾容积进行测量。结果:400例检查者脾容积的平均值为(173.94±52.17)cm3,200例男性脾容积平均值为(184.99±51.01)cm3,200例女性脾容积平均值为(162.90±51.08)cm3。脾容积与肋单元相关系数r=0.32,与上下径相关系数r=0.62,与前后径相关系数r=0.64,与脾厚径相关系数r=0.52,P0.01。结论:多层螺旋CT脾容积测量方法简便,结果较其他方法更为准确。脾脏上下径、前后径和脾厚径与脾容积相关性较大,两项以上超过正常上限,可做为判断脾脏增大的初步指标。     

16层螺旋CT测量肝炎后肝硬化脾脏体积变化的研究

目的应用16层螺旋CT测量脾脏体积,探讨肝炎后肝硬化脾脏体积、脾/肝比与Child分级间的关系。资料与方法对90例经临床资料、实验室检查、B超及CT证实的肝炎后肝硬化患者,其中肝功能Child-Pugh A级38例,B级33例,C级19例及112例正常对照者行16层螺旋CT扫描,采用仪器自带体积测量软件测量肝、脾体积,并计算出脾脏与肝脏体积比值(脾/肝比)。结果正常人脾脏体积为(211.01±112.66)cm3,脾/肝比为0.17±0.09,脾脏体积与年龄、性别、身高、体重无明显相关关系。ChildA、B级脾脏体积分别为(1016.22±580.95)cm3、(1015.72±681.46)cm3,脾/肝比为1.01±0.62及1.04±0.64,均明显高于ChildC级(644.14±416.81)cm3及0.80±0.37。结论正常人脾脏体积与年龄、性别、身高、体重无明显相关关系。肝硬化患者脾脏体积及脾/肝比较正常人显著增高,ChildA、B级出现脾/肝比倒置(>1),ChildC级脾脏体积及脾/肝比反而有所下降。     

正常成人脾脏MSCT测量及脾大分度的方法研究

目的:探讨脾脏MSCT测量及脾大分度的简捷准确方法。方法:应用MSCT重建技术测量脾脏的体积,并与以往的肋单元计数法、脾门厚度测量法等进行比较。结果:测得正常脾脏体积为78.4⁴01.2cm3,平均为202.26cm3。脾脏体积与性别因素有关。结论:MSCT重建技术测量脾脏体积更准确、简捷。     

游走脾一例

患者女,25岁.发现腹部游走包块4年,腹痛3d于2012年3月2日就诊.体检:左中下腹可触及1个5 cm×8 cm大小包块,质韧,固定,无搏动,轻度压痛.腹部超声检查:左膈下未探及脾脏回声,左中下腹实质性低回声包块,形似脾脏,回声不均匀.CT平扫及增强扫描:左侧膈下未见正常脾脏影像,脾床被胃底占据,脾脏下移至左中下腹,体积略增大,大小约为10 cm×7 cm×4 cm,脾门朝向外上方,脾蒂冗长、扭转,呈漩涡状连于脾门.脾脏平扫密度欠均匀减低,CT值约为46 HU;增强后部分脾脏未见明显强化.胰腺尾部卷曲,与脾脏动静脉伴行向下扭转,平扫及增强扫描胰腺密度未见明显异常(图1～5).CT诊断:游走脾伴脾蒂扭转,脾梗死.     

集束电极射频治疗肺癌效果的CT评估

目的　CT评价集束电极射频治疗肺癌的近期疗效。方法　对 6 8例肺癌患者通过集束电极射频治疗用CT比较手术前后肿瘤大小和密度的变化。结果　 6 8例肺癌 70个病灶射频治疗术前、术后 30min和术后 6 0d进行CT复查。单点治疗组 :病灶的体积在术后 30min增大明显 ,在术后 6 0d缩小 ,治疗前后病灶最大径分别为 (4.15± 0 .97)cm ,(5 .5 4± 1.37)cm和 (2 .79± 0 .6 8)cm ,有显著性差异 (P <0 .0 5 )。多点治疗组 :病灶的体积在 30min增加不显著 ,在 6 0d缩小不明显 ,病灶最大径分别为 (8.0 6±1.91)cm ,(9.13± 1.78)cm和 (7.6 3± 2 .16 )cm ,无显著性差异 (P >0 .0 5 )。病灶CT值在术后 30min和术后 6 0d均减低 ,单点治疗组 :治疗前、治疗后 30min及 6 0d的密度值分别为 :(49.6± 6 .2 )Hu ,(40 .5±14.4)Hu和 (35 .2± 3.2 )Hu ;多点治疗组分别为 :(46 .7± 5 .3)Hu ,(37.4± 11.8)Hu ,(35 .1± 2 .3)Hu ,以上均有显著性差异 (P <0 .0 5 )。结论　CT可判定肺癌集束电极射频治疗前后病灶大小变化和密度变化 ,给肺癌射频治疗的预后提供重要参数 ,为重复治疗提供依据     

成人髋白发育不良的CT测量评价

目的　评价成人髋臼发育不良(acetabulardysplasia,AD)的CT测量诊断方法及临床意义。方法　对33例成人AD及210例正常成人髋关节CT图像进行对照测量研究。结果　AD组与正常成人组股骨头内间隙分别为(1003±232)mm和(706±127)mm,前后唇长度之和分别为(375±072)cm和(510±051)cm,前后唇长度之和与股骨头直径比值分别为090±014和112±010,顶唇长度分别为(331±046)cm和(454±038)cm,顶唇长度与股骨头直径比值分别为085±011和101±006,前唇头距分别为(632±183)mm和(410±133)mm,后唇头距分别为(502±145)mm和(360±080)mm,臼头距分别为(978±305)mm和(534±234)mm,股骨头覆盖率为(3364±856)%[男(5003±695)%、女(5360±702)%],Sharp角分别为(4688±611)°和(3575±360)°,两组间指标的差异具有显著性意义(P<001)。并提出了各项指标的正常值。认为“光头征”及托球征”为成人AD的直接CT征象。结论　CT测量诊断成人AD优于X线平片,能直接测量髋臼各唇的长度,了解髋臼各部分的发育状况,可作为一种常规检查方法。     

多层螺旋CT后处理测量肩胛盂径线的实验研究

目的探讨多层螺旋CT(MSCT)后处理测量肩胛盂径线的方法。方法收集成人肩胛骨干标本50个、成人肩关节防腐湿标本50个,用16层螺旋CT扫描仪扫描,行轴位厚层多平面重组(MPR)、薄层多平面重组测量肩胛盂扭转角,进行统计学处理。结果肩胛盂前后最大径厚层MPR测量值(2.45±0.27)cm,干标本薄层MPR测量值(2.44±0.26)cm,湿标本薄层MPR测量值(2.59±0.32)cm;轴位盂窝深度厚层MPR测量值(2.27±0.58)mm,薄层MPR测量值(2.34±0.68)mm;轴位盂窝后松质骨深度厚层MPR测量值(1.90±0.28)cm,薄层MPR测量值(1.92±0.28)cm;轴位盂窝后1 cm松质骨宽度厚层MPR测量值(1.08±0.23)cm,薄层MPR测量值(1.02±0.20)cm;盂上下最大径厚层MPR测量值(3.36±0.30)cm,薄层MPR测量值(3.39±0.28)cm;冠状位盂窝深度干标本厚层MPR测量值(4.35±0.65)mm,湿标本厚层MPR测量值(3.90±0.93)mm,薄层MPR测量值(4.53±0.79)mm;冠状位盂窝后松质骨深度薄层MPR测量值(1.97±0.29)cm;冠状位盂窝后1 cm松质骨宽度干标本薄层MPR测量值(3.67±0.58)cm,湿标本薄层MPR测量值(3.42±0.55)cm。结论多层螺旋CT多平面重组(MPR)测量肩胛盂径线是简单、快捷的方法。     

Determination of normal splenic volume on computed tomography in relation to age, gender and body habitus

The purpose of our study was to examine variations in normal splenic size in relation to age, gender and body habitus in vivo, and to determine normative data for splenic volume on CT. The width (W), length (L), thickness (Th), cross-sectional areas and volume (Vol) of the spleen were obtained from abdominal CT examinations of 140 patients who underwent CT for indications unrelated to splenic disease. Splenic volume did not vary significantly (–0.04 < r < 0.05, p > 0.10) with the patient's age, gender, height, weight, body mass index or the diameter of the first lumbar vertebra, the latter considered as representative of body habitus on CT. The mean value of the measured splenic volume (S Vol) was 214.6 cm³ with a range from 107.2 to 314.5 cm³. S Vol correlated well with all the linear and the maximal cross-sectional area measurements and could be calculated using the formula: S Vol = 30 + 0.58 (W × L × Th.). Employing the same formula splenic volume was reliably assessed in 47 patients with clinically evident splenomegaly. Quantitative assessment of splenic volume might be of value in assessing mild variations in splenic size, because splenomegaly is the most common manifestation of splenic involvement in many disorders. Received 29 January 1996; Revision received 24 June 1996; Accepted 15 July 1996     

Gender differences in knee joint cartilage thickness, volume and articular surface areas: assessment with quantitative three-dimensional MR imaging

Objective: To compare the cartilage thickness, volume, and articular surface areas of the knee joint between young healthy, non-athletic female and male individuals. Subjects and design. MR imaging was performed in 18 healthy subjects without local or systemic joint disease (9 female, age 22.3±2.4 years, and 9 male, age 22.2±1.9 years.), using a fat-suppressed FLASH 3D pulse sequence (TR=41 ms, TE=11 ms, FA=30°) with sagittal orien- tation and a spatial resolution of 2×0.31×0.31 mm³. After three- dimensional reconstruction and triangulation of the knee joint cartilage plates, the cartilage thickness (mean and maximal), volume, and size of the articular surface area were quantified, independent of the original section orientation. Results and conclusions: Women displayed smaller cartilage volumes than men, the percentage difference ranging from 19.9% in the patella, to 46.6% in the medial tibia. The gender differences of the cartilage thickness were smaller, ranging from 2.0% in the femoral trochlea to 13.3% in the medial tibia for the mean thickness, and from 4.3% in the medial femoral condyle to 18.3% in the medial tibia for the maximal cartilage thickness. The differences between the cartilage surface areas were similar to those of the volumes, with values ranging from 21.0% in the femur to 33.4% in the lateral tibia. Gender differences could be reduced for cartilage volume and surface area when normalized to body weight and body weight×body height. The study demonstrates significant gender differences in cartilage volume and surface area of men and women, which need to be taken into account when retrospectively estimating articular cartilage loss in patients with symptoms of degenerative joint disease. Differences in cartilage volume are primarily due to differences in joint surface areas (epiphyseal bone size), not to differences in cartilage thickness. Received: 19 June 2000 Revision requested: 4 August 2000 Revision received: 30 November 2000 Accepted: 6 December 2000     

Determination of splenomegaly by coronal oblique length on CT

Purpose

The aims of this study were (a) to determine whether a coronal oblique length (COL) > 12 cm, which is often used to detect splenomegaly (SM) on ultrasound, can be used as a marker of SM on computed tomography (CT), (b) to compare the diagnostic accuracy of COL with other unidimensional linear measurements (ULM) in identifying SM, (c) to determine which ULM most closely correlates with splenic volume (SVol) according to the splenic index on CT, (d) to assess the relationship between SVol and patient’s gender, age and body parameters (height, weight), and (e) to determine whether there is a difference between non-contrast-enhanced and contrast-enhanced CT images in identifying SM.

Materials and methods

The body parameters and ULM (width, length, thickness, COL) were obtained from patients who underwent CT for various indications from April 2016 to April 2017. SVol and body mass indexes were calculated for each patient.

Results

Of the 1078 patients [male/female = 526/552; 47.57 (mean) ± 19.21 (standard deviation) years], 392 patients had SM. The sensitivity, specificity, positive and negative predictive values of COL > 12 cm for diagnosing SM were 44.6, 95.6, 85.3 and 75.1%, respectively (p < 0.001). SVol correlated with all ULM (p < 0.001). In the non-SM group (n = 686), the mean SVol was 331.7 ± 92.2 cm³ and females had smaller spleens than males (p < 0.001). SVol showed correlation with gender, age and height (p < 0.001).

Conclusion

COL > 12 cm is not superior to other ULM for the detection of SM, but it is very successful in determining normal spleens. The unidimensional measurements and volume of the spleen should be calculated by taking gender and body parameters into account for different ethnic populations. Non-contrast-enhanced CT can also be used to detect SM.

     

A novel, simple method of functional spleen volume calculation by liver-spleen scan.

Spleen enlargement is commonly associated with portal hypertension from cirrhosis and may cause thrombocytopenia. Thus, accurate assessment of spleen size may be helpful in the clinical evaluation. Spleen length is not a precise estimate of spleen size because of the variation in spleen configuration, and spleen volumes measured by edging techniques can be tedious. We present a new method of measuring the functional spleen volume by liver-spleen scan (LSSs), validation experiments and some clinical data. METHODS: The method involves measurement of the total spleen counts by SPECT and dividing by a representative voxel concentration on a single frame to obtain the organ volume. Validation included phantom studies and clinical evaluation in 443 consecutive patients, including 216 with histologic assessments of chronic liver disease (CLD) and 11 healthy volunteers. RESULTS: A calibration factor determined from phantoms was used to convert the calculated volume (CV) to the "true" volume (V): V = CV (0.956) - 66.5 (r = 0.9991; P < 0.001). The volume calculations were validated in a second group of phantoms (r= 0.981; P < 0.0001). Spleen volumes were expressed as volume (cm3) and as volume per pound ideal body weight (IBW) (cm3/lb) (the conversion factor to convert cm3/lb IBW to cm3/kg IBW is 2.2). Clinical studies of reproducibility included demonstration of a significant (P < 0.0001) linear correlation between volumes calculated from repeat LSSs within 9 mo of the initial LSS in 11 healthy volunteers and 32 patients with CLD: y = 1.02x - 25; r = 0.968. The correlation with spleen volumes from autopsy or splenectomy was significant: y = 0.766x + 57; r = 0.845; P < 0.001. The normal spleen volume in 11 patients was 201 +/- 77 cm3 and 1.43 +/- 0.68 cm3/lb IBW (upper limits of normal: 335 cm3 or 2.5 cm3/lb IBW). In 443 consecutive LSSs over 15 mo, half of the patients had spleen volumes above the upper limits of healthy volunteers, and CLD was present in 90.9% of these patients. In 216 patients with histologically proven liver disease, a progressive increase in the percentage of spleen volumes above the upper limits of normal was noted from no fibrosis (10%) to mild to moderate fibrosis (36.7%) to early cirrhosis (52%) to advanced liver disease (75%). The correlation of spleen volume with platelet count was excellent (r = 0.7635; P < 0.005). CONCLUSION: This novel spleen volume measurement detects serious liver disease and correlates with splenic hyperfunction.     

Determination of splenomegaly by CT: is there a place for a single measurement?

OBJECTIVE: Our objective was to determine if there is a single parameter that can be used as a marker of splenomegaly using CT. MATERIALS AND METHODS: Splenic length, width, and thickness were measured in 249 CT scans and multidimensional indexes were obtained from the multiplication of these measurements. Volume was calculated by summing the volumes of multiple contiguous scans. The relationship of the spleen to the left liver lobe and inferior third of the left kidney was also evaluated. Linear equations were obtained to correlate each measurement to the splenic volume. RESULTS: The unidimensional measurements with best correlation to volume were splenic length (r = 0.81, p < 0.01) and width (r = 0.804, p < 0.01). Correlation was better for the multidimensional indexes (r = 0.95, p < 0.01). Using a previously described upper limit of normality for splenic volume of 314.5 cm3 in the linear regression equation obtained, a maximum spleen length of 9.76 cm was the upper limit of normality. The relation of the lowest point of the spleen to the inferior third of the kidney also showed that if the spleen reached or extended below this portion of the kidney, it could be used as evidence of splenomegaly (p < 0.005), although it had a low sensitivity. CONCLUSION: Splenic length and multidimensional indexes correlate well with splenic CT volume. A splenic length of 9.76 cm can be used to accurately diagnose splenomegaly and can replace multiple-measurement, time-consuming methods in the clinical routine.     

Contrast-enhanced MR imaging of diffuse and focal splenic disease with use of magnetic starch microspheres

The diagnostic value of magnetic starch microspheres (MSM), a new superparamagnetic contrast agent, was studied in experimental models of diffuse and focal splenic disease in rats by means of ex vivo relaxometry and in vivo magnetic resonance (MR) imaging. Owing to small differences in unenhanced T1 and T2 values between diffuse lymphoma and normal spleen, MR imaging failed to distinguish tumor-bearing animals from control animals by signal-to-noise ratios (SNRs) obtained with T1- and T2-weighted spin-echo sequences. One hour after injection of 20 μmol/kg MSM, lymphomatous spleen showed significantly (P <.001) reduced enhancement relative to normal splenic tissue. As a result, animals with diffuse lymphoma (SNR: 10.3 ± 1.7) could be easily differentiated from control animals (SNR: 5.5 ± 0.6) on T2-weighted (TR msec/TE msec = 2,000/45) images. In focal splenic disease, MSM produced normal enhancement of nontumorous splenic tissue, whereas relaxation times of tumors were not different before and after contrast agent injection. On T2-weighted images (2,000/45), the tumor-spleen contrast-to-noise ratio increased from (4.8 ± 1.6 to 21.8 ± 1.9 +354%), improving conspicuity of splenic tumors. The results show that MSM-enhanced MR imaging improves the detection of diffuse and focal splenic disease.     

Quantification of blood flow in the middle cerebral artery with phase-contrast MR imaging

The aim of this study was to assess blood flow in the middle cerebral artery (MCA) according to age, gender, and side. Eighty-eight subjects without carotid obstruction were measured for mean velocity, vessel area, and volume flow rates of both MCA with phase-contrast MR. A high-resolution sequence with a matrix of 300 × 512 and a double oblique localizing strategy was used for measurement. A mean velocity of 33 ± 6.8 cm/s, a mean vessel area of 6.2 ± 1.2 mm² and a mean flow rate of 121 ± 28 ml/min were measured in the MCA. Lower volume flow rates were seen in subjects aged over 50 years (p < 0.01). When comparing women with men, a lower vessel area (p < 0.05) of the MCA was counterbalanced by a higher velocity, resulting in no significant difference of the volume flow rate. No difference occurred between the right and the left side. Flow reduction occurs in the elderly. A lower vessel area of the MCA in women is compensated by a higher velocity. Received: 3 September 1999; Revised: 17 January 2000; Accepted: 23 February 2000     

MR assessment of pituitary gland morphology in healthy volunteers: age- and gender-related differences.

PURPOSE AND METHODS: High-field MR images at 1.5 T were used to characterize the effects of age and gender on pituitary size and shape in a sample of 71 adult volunteers (40 females), aged 21 to 82 years. FINDINGS: For all subjects, age was inversely correlated with pituitary height (r = -.43, P less than .0002) and cross-sectional area (r = -.35, P less than .0028). Age-specific gender differences were also present in pituitary height and area. A convex upper pituitary margin was more common in females (P = .002) and younger subjects (P = .009). CONCLUSIONS: This study confirms that aging is accompanied by gender-specific changes in pituitary size and shape, and provides normative data that may facilitate evaluation of the pituitary gland in neuroendocrine disorders.     

CT measurement of trunk muscle areas in patients with chronic low back pain

PURPOSE: The objective of this study was to determine the cross-sectional area changes of the paraspinal, isolated multifidus, quadratus lumborum, psoas, and the gluteus maximus muscles with CT in patients with chronic low back pain. MATERIALS AND METHODS: In this study, we evaluated 36 patients with chronic low back pain and 34 healthy volunteers. The mean age of the patients was 43.2 +/- 6.9 years (range, 30- 58 years) and the mean age of control group was 44.4 +/- 6.9 years (range, 31-61 years). We defined pain that lasts more then one year as chronic pain. Female patients were selected for standardization. All patients were housewives. None of the patients or controls engaged in physical activity other than routine housework. We used a visual analog scale and the Oswestry Pain Questionnaire for clinical evaluation. We made CT cross-sections of the paraspinal muscles at the upper and lower endplates of L4, and of the gluteus maximus at the head of the interfoveal level. RESULTS: In the patient group the multifidus, psoas, and quadratus lumborum cross-sectional areas were smaller than in the control group, and the P values were P = 0.002, P = 0.042, and P = 0.047, respectively, at the L4 endplate. At the L4 endplate level, cross-sectional areas of the multifidus and paravertebral muscles in the patient group were smaller than in the control group, and the difference was statistically significant (P = 0.001, P = 0.010, respectively). We did not find any significant difference between the patient and the control groups in gluteus maximus cross-sectional area. CONCLUSION: Chronic low back pain caused atrophy of the paraspinal, isolated multifidus, quadratus lumborum, psoas, and the gluteus maximus muscles to varying degrees, which was most prominent in the multifidus. Atrophy was noted in all of the studied muscles, except the gluteus maximus. The reliability of CT in measuring the cross-sectional areas of the back muscles was acceptable.