腰椎间盘退变的MR定量分析:MRS和T1ρ成像技术

目的 探讨MRS和T1ρ成像技术定量评估腰椎间盘的退变程度的应用价值。方法 收集腰痛患者64例,按年龄分为<30岁组（10例）、30~39岁组（12例）、40~49岁组（11例）、50~59岁组（15例）、>59岁组（16例）。对每例患者选取2个腰椎间盘进行MRS扫描,获得髓核氮-乙酰氨基峰下面积（N-acetyl）、水峰下面积（Water）,及N-acetyl/Water值;并行T1ρ成像,分别测量髓核及纤维环T1ρ值。比较不同Pfirrmann分级及年龄组间MRS及T1ρ定量分析结果的差异,并分析Pfirrmann分级和年龄与T1ρ和MRS定量分析结果的相关性。结果 64例患者共128个椎间盘中,Pfirrmann Ⅱ级61个,Ⅲ级40个,Ⅳ级23个,Ⅴ级4个。不同Pfirrmann分级椎间盘间及不同年龄组间,髓核T1ρ、N-acetyl、Water及N-acetyl/Water值差异均有统计学意义（P均<0.01）,纤维环T1ρ值差异无统计学意义（P>0.05）。N-acetyl、N-acetyl/Water、髓核T1ρ值,随Pfirrmann分级增加、患者年龄增大,均呈下降趋势。结论 MRS和T1ρ成像技术均可用于腰椎间盘退变的定量评估,且与Pfirrmann分级具有良好的相关性。     

MR体素内不相干运动弥散加权成像评估腰椎间盘退变程度

目的 观察MR体素内不相干运动-弥散加权成像（IVIM-DWI）定量评估腰椎间盘退变程度的价值。方法 对90例下腰痛患者采集共450个腰椎间盘常规MRI及IVIM-DWI，评估各椎间盘Pfirrmann分级，比较不同Pfirrmann分级椎间盘之间IVIM-DWI定量参数表观弥散系数（ADC）、慢速弥散系数（D）、快速弥散系数（D^*）及灌注分数（f）的差异；采用有序logistic回归分析及受试者工作特征（ROC）曲线评价IVIM-DWI定量参数诊断腰椎间盘退变Pfirrmann分级的效能。结果 450个椎间盘中，21个PfirrmannⅠ级，168个Ⅱ级，152个Ⅲ级，87个Ⅳ级，22个Ⅴ级。PfirrmannⅠ与Ⅱ级之间髓核ADC、D值及前纤维环ADC，Ⅱ与Ⅲ级间髓核ADC、D和f值及前、后纤维环ADC、D值，Ⅲ与Ⅳ级间髓核ADC、D、f值、前纤维环ADC、D值及后纤维环ADC，Ⅳ与Ⅴ级间髓核ADC、D值及后纤维环D值差异均有统计学意义（P均<0.05）；相邻Pfirrmann分级间其余IVIM-DWI定量参数差异均无统计学意义（P均>0.05）。髓核ADC（OR=1.879）及D值（OR=2.212）均为腰椎间盘退变Pfirrmann分级的相关因素（P均<0.001）。髓核ADC及D值评估Pfirrmann分级的曲线下面积为0.80~0.92。结论 IVIM-DWI可有效定量评估椎间盘退变程度。     

能谱CT基物质成像定量、定性评估腰椎间盘退变

目的 探讨能谱CT基物质成像定量、定性评估腰椎间盘退变的价值。方法 对82例腰腿痛患者采集腰椎能谱CT和MRI,获取74 keV CT、水 和CS(水)基物质图;根据Pfirrmann分级(PG)标准基于MRI行椎间盘分级,比较不同PG级别腰椎间盘髓核(NP)及纤维环(AF)的CT值、水(CS)及CS(水)浓度,分析其与PG的关系。基于水(CS)和CS(水)伪彩色图对腰椎间盘进行视觉分型,比较不同分型之间PG级别分布及其与PG的相关性。结果 共纳入250个腰椎间盘,其中 PG Ⅰ级22个、Ⅱ级49个、Ⅲ级83个、Ⅳ级96个。不同PG级别椎间盘之间,前AF、NP及后AF的CT值及水(CS)及CS(水)浓度总体差异均有统计学意义(P均<0.001),其CT值均与PG呈负相关(r_s=－0.504、－0.399、－0.258,P均<0.001),水(CS)浓度均与PG呈正相关(r_s=0.476、0.753、0.324,P均<0.001)而CS(水)浓度均与PG呈负相关(r_s=－0.486、－0.760、－0.329,P均<0.001)。不同视觉分型椎间盘间PG级别差异均有统计学意义(P均<0.001),且视觉分型与PG级别均呈正相关(r_s均≥0.700,P均<0.001)。结论 能谱CT基物质成像可用于定量、定性评估腰椎间盘退变。     

MRI表观弥散系数与腰椎间盘退变分级的相关性

目的 探讨腰椎间盘髓核弥散能力与其退变程度、解剖水平的相关性。方法 收集符合纳入标准的慢性下腰痛患者42例,行腰椎MRI,扫描序列为矢状位T1W、T2W及轴位T2W、DTI,椎间盘按Pfirrmann分级。测量不同退变分级及不同解剖水平各椎间盘髓核相对ADC值并进行比较,分析椎间盘退变分级、解剖水平与ADC值的相关性。结果 210个椎间盘(L_1-2~L₅-S₁各42个),Pfirrmann分级Ⅱ~Ⅴ级分别为73个、95个、38个、4个。所有椎间盘相对ADC值平均为0.45±0.10,Ⅱ~Ⅴ级分别为0.48±0.08、0.45±0.10、0.42±0.09、0.23±0.15;L_1-2~L₅-S₁分别为0.44±0.08、0.45±0.08、0.45±0.10、0.45±0.11、0.45±0.12。不同退变分级椎间盘的ADC值差异有统计学意义(P<0.01);两两比较,除Ⅲ级与Ⅳ级两组总体无差异(P＞0.05)外,其他各级之间差异均有统计学意义(P<0.05)。椎间盘ADC值与Pfirrmann退变分级具有相关性(r=-0.25,P<0.05)。结论 DTI可定量评价椎间盘退变。     

超短回波时间MRI用于腰椎间盘软骨终板成像

目的 探讨超短回波时间（UTE）MR序列及常规序列在腰椎间盘软骨终板损伤中的应用价值。方法 对87名志愿者行MR常规序列及UTE序列腰椎成像,分析UTE序列显示的腰椎间盘软骨终板损伤与椎体Modic改变、Pfirrmann椎间盘退变分级之间的相关性。结果 UTE序列成像中,椎体软骨终板显示为非钙化性软骨终板及钙化性软骨终板。L₁~S₁各节段软骨终板损伤与椎体Modic改变分型、Pfirrmann椎间盘退变分级均呈正相关（P均<0.001）。结论 与MR常规序列比较,UTE序列成像可以清楚显示腰椎间盘软骨终板分层及其损伤,且软骨终板损伤与腰椎退变存在一定关系。     

椎间盘源性下腰部疼痛患者腰椎间盘MRI高信号区发生特点

目的 探讨椎间盘源性下腰部疼痛(LBP)患者腰椎间盘MRI高信号区(HIZ)发生特点与规律。方法 对72例椎间盘源性LBP患者(LBP组)、30例无LBP病史患者(对照组)行1.5T腰椎MRI, 评价所有节段腰椎间盘退变程度及HIZ, 并对采集数据进行统计学分析。结果 两组患者HIZ均发生于Ⅲ-Ⅴ级退变椎间盘, 以L_3-4、L_4-5、L₅-S₁腰椎间盘最易受累。LBP组HIZ阳性34例, 共累及99个腰椎间盘, 25例为多发HIZ(HIZ累及≥2个腰椎间盘);对照组HIZ阳性11例, 共累及21个腰椎间盘, 4例为多发HIZ。两组患者椎间盘HIZ发生率(LBP组:99/360, 27.50%;对照组:21/150, 14.00%)、多发HIZ患者数差异均有统计学意义(χ ²=10.725、5.010, P=0.001、0.025)。结论 HIZ是Ⅲ级以上椎间盘退变的表现, 并不是椎间盘源性LBP的特异性征象, 但LBP患者椎间盘HIZ发生率增高, 多椎间盘受累对提示椎间盘源性LBP诊断有重要意义。     

MR体素内不相干运动弥散加权成像及T2 mapping评估腰椎间盘退行性变

目的 观察MR体素内不相干运动弥散加权成像(IVIM-DWI)及T2 mapping技术评估腰椎间盘退行性变(IVDD)的价值。方法 前瞻性纳入19例下腰部疼痛患者和31名健康志愿者,采集L1~S1椎体矢状位T2WI、T2 mapping及IVIM-DWI;根据Pfirrmann标准进行IVDD分级,观察不同分级及不同层面椎间盘T2值及其对应上、下位椎体IVIM参数的差异,并进行相关性分析,评价其诊断价值。结果 不同Pfirrmann分级椎间盘之间,前纤维环(AAF)、髓核(NP)和后纤维环(PAF)T2值差异及对应下位椎体表观弥散系数(ADC)差异均有统计学意义(P均＜0.05),不同层面椎间盘NP、PAF的T2值差异均有统计学意义(P均＜0.05)。椎间盘PAF的T2值与其上、下位椎体ADC呈正相关(r=0.128、P=0.043,r=0.148、P=0.019);椎间盘Pfirrmann分级与AAF、NP及PAF的T2值均呈负相关(r=－0.187、P=0.003,r=－0.579、P＜0.001,r=－0.401、P＜0.001),与其上、下位椎体慢ADC(ADC_slow)均呈正相关(r=0.196、 P=0.002,r=0.126、P=0.046);椎间盘层面位置(L_1-2→L₅-S₁)与NP及PAF的T2值均呈负相关(r=－0.183、P=0.004,r=－0.356、P＜0.001),而与其上、下位椎体ADC_slow呈正相关(r=0.196、P=0.003,r=0.126、P=0.026)。结论 IVIM-DWI及T2 mapping技术用于评估IVDD具有一定潜在价值,以椎间盘T2值及其对应下位椎体ADC的价值较高。     

3.0T磁共振T2* mapping成像诊断腰椎间盘退变

目的 评价T2^* mapping成像技术在诊断腰椎间盘退变中的临床应用价值。方法 对12例下腰痛患者(症状组)及12名无症状志愿者 (对照组)行腰椎间盘MR扫描,在L₁-S₁共120个椎间盘放置ROI,测量相应的T2^*值,并按Pfirrmann标准对常规 T2WI显示的椎间盘进行分级,分析并比较症状组和对照组腰椎间盘内T2^*值的差异,对T2^*值与椎间盘分级间的相关性采用Spearman相关分析。结果 症状组椎间盘Pfirrmann分级平均得分高于对照组(t=5.04,P<0.05)。症状组腰椎间盘平均T2^*值为(76.90±33.10)ms,低于对照组[(116.00±71.60)ms,P<0.05]。症状组和对照组T2^*值均与Pfirrmann分级呈负相关(r=-0.84、-0.76,P均<0.05)。结论 T2^* mapping成像技术能为影像学量化诊断腰椎间盘退变提供依据。     

双能量CT虚拟去钙成像评估腰椎间盘退变

目的 分析双能量CT（DECT）虚拟去钙（VNCa）成像评估腰椎间盘退变（IDD）的可行性。方法 回顾性分析37例接受腰椎DECT和MR检查的慢性腰痛患者,根据改良Pfirrmann分级（mPG）标准对MRI所示椎间盘进行分级,评估IDD程度;对DECT数据行后处理,获得线性融合CT图像（相当于常规CT）和VNCa灰度图及彩色编码图。于常规CT和VNCa灰度图上测量腰椎间盘髓核的CT值,分析其与mPG的相关性。根据VNCa彩色编码图中椎间盘髓核和纤维环衰减程度对椎间盘进行视觉分型,比较不同分型间mPG差异,并分析VNCa视觉分型与mPG的关系。结果 共纳入168个腰椎间盘,包括12个mPG 1级、39个2级、47个3级、50个4级和20个5级及以上,51个VNCa视觉分型Ⅰ型、51个Ⅱ型和66个Ⅲ型。在VNCa灰度图上,各mPG分级髓核CT值差异均有统计学意义（P均<0.001）。常规CT上,mPG 2级与3级、4级与5级及以上之间髓核CT值差异均无统计学意义（P=0.173、0.083）,其余各mPG分级间髓核CT值差异均有统计学意义（P均<0.05）。常规CT和VNCa灰度图中,髓核CT值与mPG分级均呈正相关（r=0.504、0.745,P均<0.001）。VNCa视觉分型与mPG分级呈正相关（r=0.900,P<0.001）,不同VNCa分型间mPG分级差异有统计学意义（H=82.610,P<0.001）。结论 DECT-VNCa成像可用于评估腰椎间盘IDD。     

腰椎间盘退变的磁共振T2 map定量研究

目的 探讨T2 map成像定量评价早期腰椎间盘退变的价值。方法 对46名受试者行腰椎MR矢状位T2WI及正中矢状位T2 map成像,根据Pfirrmann标准将L₁-S₁椎间盘分级,并测量髓核及纤维环前后缘T2值。分别比较各级髓核和纤维环前后缘T2值,对髓核和纤维环前后缘T2值与年龄、退变分级的相关性进行分析。采用单因素方差分析和Pearson相关分析。结果 共计测量229个椎间盘:①各分级腰椎间盘髓核T2值随分级增高而减小,除Ⅳ级与Ⅴ级,余各级间差异均有统计学意义(P<0.05);②各分级腰椎间盘纤维环前缘T2值呈上升趋势,除Ⅰ级、Ⅱ级与Ⅳ级,余各级间差异均无统计学意义(P＞0.05);③腰椎间盘髓核T2值与受试者年龄呈显著负相关(P<0.01),纤维环前、后缘T2值与受试者年龄无明显相关性(P＞0.01)。结论 基于T2 map成像定量测定腰椎间盘髓核T2值的变化是一种无创评价椎间盘早期退变的方法。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

手转胎头术失败的原因与分娩结局临床分析

目的 探讨手转胎头术失败的原因与分娩结局.方法 选择2008年1月至2010年12月于我院住院分娩的持续性枕横位、枕后位产妇198例,根据行手转胎头术后结果分为成功组126例、失败组72例.比较两组分娩结局,对比分析失败原因.结果 失败组胎儿体质量≥3500 g的发生率[76.4％(55/72)]明显高于成功组[31.7％(40/126)],差异有统计学意义(x2=30.177,P=0.001)、失败组宫缩乏力发生率[58.3％(42/72)]高于成功组[38.1％ (48/126)],差异有统计学意义(x2=7.569,P=0.006)、失败组骨盆临界或轻度狭窄发生率[38.9％ (28/72)]高于成功组[23.8％(30/126)],差异有统计学意义(x2 =5.030,P=0.002)、失败组手转胎头时机不当(宫口开大＜6 cm、胎头位于坐骨棘上及宫口开大8～10 cm、胎头位于坐骨棘下≥2 cm)发生率[61.1％(44/72)]高于成功组[38.9％(49/126)],差异有统计学意义(x2=9.084,P=0.003).失败组母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率高于成功组(x2 =9.586,P=0.002、x2=9.334,P=0.002、x2=5.910,P=0.015、x2=5.240,P=0.022)、失败组剖宫产发生率[72.2％(52/72)]明显高于成功组[34.1 ％(43/126),x2=26.641,P=0.001)].结论 手转胎头术能使难产变顺产,降低剖宫产率,减少母儿并发症,但须积极预防、处理导致手转胎头术失败的原因,对矫正失败后继续矫正及试产应慎重.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.     

Evidence-Based Pain Management and Palliative Care in Issue Four for 2009 of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly. Issue 4 for 2009 contains 4027 complete reviews, 1906 protocols for reviews in production, and 11447 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 600,000 randomized controlled trials, and 12,200 cited papers in the Cochrane methodology register. The health technology assessment database contains over 7500 citations. This edition of the Library contains 90 new reviews, of which 19 have potential relevance for practitioners in pain and palliative medicine.     

Wie zuverlässig sind Angaben zu nichtentzündlichen ausgedehnten Schmerzen?

ZusammenfassungFragestellung Es wurde geprüft, wie sich der Differenziertheitsgrad zweier Schmerzmessmethoden auf Angaben zur Ausgedehntheit klinischer Schmerzen auswirkt. Zugleich wurde der Referenzzeitraum variiert, über den die Patienten berichten sollten.Methode Erfasst wurde der Einfluss zu Lasten der Befragungsdifferenziertheit durch den Vergleich zweier Körperschema-Bildvorlagen. Drei Referenzzeiträume (Schmerz aktuell, letzte Woche, letztes halbes Jahr) wurden vorgegeben.Ergebnisse Patienten mit ausgedehnten Schmerzen gaben bei differenzierter Befragung um so mehr Schmerzen an, je weiter die Schmerzen zurück lagen und je größer der Berichtszeitraum war. Patienten mit gelenknahen Schmerzen gaben bei hoch differenzierter Befragung weniger ausgedehnte Schmerzen in der Vergangenheit an als bei globaler Einschätzung. Patienten mit Rückenschmerzen berichteten bei differenzierter Befragung zum aktuellen Schmerz über weniger ausgedehnte Schmerzen als bei globaler Befragung.Schlussfolgerung Die Angaben zur Schmerzausdehnung variieren vor allem bei Patienten mit ausgedehnten Schmerzen in Abhängigkeit von der Differenziertheit der Befragung. In diesen Fällen ist die Wahrscheinlichkeit erhöht, dass sich die Beschwerdesymptomatik zumindest teilweise erst in der Reaktion auf die situativen Befragungsbedingungen konstituiert und daher nicht auf andere Befragungsbedingungen generalisiert werden kann.