光谱CT肺动脉成像定性诊断肺动脉栓塞及定量评估肺组织灌注

目的 观察光谱CT肺动脉成像(SCTPA)定性诊断肺动脉栓塞(PE)和定量评估肺组织灌注的价值。方法 回顾性分析37例临床诊断PE患者的CTPA资料,观察常规CTPA及SCTPA后处理图像,后者包括40 keV虚拟单能量图(VMI_{40 keV})、碘密度图(IDI)与有效原子序数(Z-eff)图的融合图及电子密度图(EDI);记录2种图像中肺段动脉、肺亚段及以下动脉内的栓子数量和位置,对比其中相应肺灌注缺损区与对侧相应正常肺实质区常规CT值、碘密度(ID)、Z-eff及电子密度(ED)的差异;针对差异有统计学意义的sCTPA参数绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评估其区分PE肺灌注缺损区与正常肺实质的效能。结果 37例中,仅以常规CTPA检出37个栓子,其中26个位于肺段动脉、11 个位于肺亚段及以下动脉;之后结合SCTPA后处理图像额外检出1个肺段动脉和2个肺亚段以下动脉内栓子。全部40个栓子对应肺灌注缺损区常规CT值高于、ID及Z-eff均低于对侧正常肺实质区(P均<0.01),而ED与正常肺实质区差异无统计学意义(P=0.54)。以常规CT值区分肺灌注缺损区与正常肺实质区的敏感度、特异度分别为42.50%及87.50%,以ID及Z-eff区分的敏感度分别为95.00%、97.50%,特异度均为100%。ID及Z-eff的AUC均为0.99,均高于常规CT值(0.65,Z=5.56、5.53,P均<0.01),而 ID与Z-eff的AUC差异无统计学意义(Z=0.71,P=0.48)。结论 利用SCTPA可提高PE检出率及定量评估肺组织灌注;根据ID及Z-eff可有效区分肺灌注缺损区与正常肺实质。     

肺动脉CTA漏诊亚段肺栓塞原因分析

目的 探讨CTPA漏诊亚段肺栓塞（SSPE）的常见原因。方法 对临床确诊肺栓塞（PE）的91例患者的影像学资料进行回顾性分析,计算首诊CTPA、复诊CTPA及经查看肺通气/灌注（V/Q）显像结果后复诊CTPA对SSPE的检出率,并与V/Q显像结果进行比较。结果 91例PE患者中,3 494支亚段肺动脉显示清楚。肺V/Q显像对SSPE的检出率为19.00%（664/3 494）,首诊CTPA的检出率为11.99%（419/3 494）,差异有统计学意义（χ²=65.59,P<0.01）;复诊CTPA检出率为13.62%（476/3 494）,低于肺V/Q显像（χ²=37.05,P<0.01）;查看肺V/Q显像结果后,复诊CTPA对SSPE的检出率为15.83%（553/3 494）,与肺V/Q显像比较差异有统计学意义（χ²=12.26,P<0.01）。结论 CTPA漏诊SSPE的原因主要包括亚段肺动脉观察困难、诊断水平较低和对慢性PE诊断困难。提高阅片医师注意力和针对性,并联合肺V/Q显像,可提高CTPA对SSPE的检出率。     

第二代双源CT双能量成像对肺栓塞的诊断价值研究

目的：探讨西门子第二代双源CT（Somatom Definition Flash）双能量成像对肺动脉栓塞的诊断价值。方法：回顾性研究42位临床疑诊肺栓塞行双能量肺血管成像（DE-CTPA）扫描的患者的资料,利用工作站双能量软件Lung PBV（肺灌注）、Lung Vessels（肺血管）进行彩色编码成像。2名胸部影像医师结合DE-CTPA与软件提供的信息做出诊断。结果：根据临床及CT结果,其中32例（76.2%,32/42）存在肺动脉栓塞,28例在CTPA上表现为肺动脉充盈缺损, 4例在CTPA上未见异常征象,而双能量成像上表现为亚段或以下水平灌注或充盈缺损。双能量Lung PBV测得32例48个栓塞肺区CT强化值（35.6±12.1） HU,低于非栓塞区域所测得的CT强化值（44.5±10.6） HU,t=-2.336,P=0.027。结论：双能量Lung PBV与Lung Vessels软件能显示肺栓塞所致的灌注及充盈缺损,结合CTPA能提高肺栓塞的检出率,特别是外周性肺动脉栓塞。     

CT肺动脉成像联合下肢静脉成像评估肺动脉栓塞与下肢深静脉血栓的相关性

目的探讨应用CT肺动脉成像(CTPA)联合下肢静脉成像(CTV)技术,分析肺动脉栓塞(PE)与下肢深静脉血栓(DVT)关系的价值.方法 回顾性分析374例因怀疑下肢深静脉血栓而接受CTPA联合下肢CTV检查的患者资料,分别评估左下肢、右下肢、双下肢DVT并发PE的风险,分析PE与下肢DVT的相关性.结果 共检出下肢DVT 288例,PE 155例;下肢DVT合并PE共145例.共检出DVT病变血管321条,左下肢DVT的发生率(211/321,65.73%)明显高于右下肢(110/321,34.27%),差异有统计学意义(χ²=71.783,P<0.001).50.35%(145/288)的下肢DVT患者合并PE,左下肢、右下肢、双下肢DVT合并PE患者分别占44.38%(79/178)、58.44%(45/77)、63.64%(21/33),差异有统计学意义(χ²=6.883,P=0.032).93.55%(145/155)的PE患者合并下肢DVT,PE合并左下肢、右下肢、双下肢DVT的患者分别占50.97%(79/155)、29.03%(45/155)、13.55%(21/155),差异无统计学意义(χ²=13.025,P>0.05).PE与DVT呈正相关(r=0.8).结论 PE的发生与下肢DVT呈正相关,应用CTPA联合下肢CTV诊断下肢DVT可同时判断是否合并PE,有利于及时合理治疗,减低PE病死率.     

双源CT一站式扫描诊断急性肺栓塞与深静脉血栓

目的 评价双源CT(DSCT)一站式扫描对急性肺栓塞(PE)及深静脉血栓(DVT)的诊断价值。方法 采用DSCT对56例临床疑诊急性PE患者先行肺动脉成像(CTPA),间隔120~180 s后再行深静脉成像(CTV)。利用MPR和MIP观察PE和DVT分布情况。56例中,12例于CTPA检查发现PE后接受DSA检查。以血管节段为单位,记录双源CT和DSA对PE和DVT的诊断结果,并与DSA检查结果进行比较。结果 12例PE患者中发现DVT 11例,CTPA对肺段及亚段动脉PE的检出率明显高于DSA(χ²=8.34、92.65,P均<0.01),对肺叶动脉及以上级别血管PE的检出率与DSA差异无统计学意义(P均>0.05)。CTV对DVT的检出率与DSA相比差异无统计学意义(χ²=0.667,P=0.414)。以DSA为金标准,CTV评价DVT的敏感度、特异度、准确率分别为92.16%(47/51)、96.49%(55/57)、94.44%(102/108)。结论 双源CT一站式扫描可同时准确地诊断急性PE及DVT。     

MSCT与MR肺动脉成像对肺动脉栓塞的诊断价值

目的：比较多层螺旋CT肺动脉成像（MSCT pulmonary angiography,MSCTPA）及磁共振肺动脉成像（MR pulmonary angiography,MRPA）对肺动脉栓塞（Pulmonary embolism,PE）的诊断价值。方法：对50例拟诊为PE的患者,42例采用双源CT行肺动脉成像,观察肺动脉栓子的部位、数目、形态等直接征象,观察肺叶继发改变;8例行1.5T MRPA,其中3例补充行三维增强磁共振肺动脉成像（3D-CE-MRPA）检查,观察肺动脉栓子的特点。结果：42例中,MSCTPA共发现栓子657支,其中段以上栓子481支,包括中心型栓子176支、附壁型259支、完全阻塞型46支。间接征象包括马赛克征、肺梗死、胸腔积液、肺动脉增粗等。8例MRPA共诊断左、右肺动脉栓塞9支,叶肺动脉栓塞19支。非增强MR成像对肺段动脉栓塞诊断受到限制。3例行3D-CE-MRPA的患者中,段及以上及大部亚段肺动脉栓塞显示清楚。结论：MSCTPA能够方便、快捷、清楚地显示肺动脉栓子;MRI平扫可以发现肺叶动脉以上的栓子,肺段动脉栓子部分可见;3D-CE-MRPA可以发现肺段及大部分亚段肺动脉栓子,诊断效能接近CTPA。     

SPECT/CT肺灌注显像评价肺动脉球囊扩张成形术治疗慢性血栓栓塞性肺动脉高压效果

目的 以SPECT/CT肺灌注显像评价肺动脉球囊扩张成形术（BPA）治疗慢性血栓栓塞性肺动脉高压（CTEPH）的疗效。方法 对18例CTEPH患者分别于BPA前及其后1~3个月内行SPECT/CT肺灌注显像，以经导管肺动脉造影为标准，评价BPA前、后SPECT/CT探测肺段灌注缺损及灌注改善情况。结果 SPECT/CT肺灌注显像在BPA前探测肺段灌注缺损的敏感度、特异度、准确率、阳性预测值（PPV）及阴性预测值（NPV）分别为90.42%（302/334）、99.05%（418/422）、95.24%（720/756）、98.69%（302/306）及92.89%（418/450）；BPA后探测灌注改善的敏感度、特异度、准确率、PPV和NPV分别为77.78%（56/72）、80.00%（24/30）、78.43%（80/102）、90.32%（56/62）及60.00%（24/40）。结论 SPECT/CT肺灌注显像用于评价BPA治疗CTEPH后肺段灌注及改善具有较好临床价值。     

双源螺旋CT三种扫描模式肺动脉造影诊断肺栓塞

目的 比较双源螺旋CT双能量模式（DE）、单能量模式（SE）和单能量低kV（SE_LOW）3种模式下CT肺动脉造影（CTPA）图像质量、辐射剂量和肺动脉栓子分布的差异。方法 将130例临床疑诊肺动脉栓塞（PE）而接受CTPA患者随机分为DE组（43例）、SE组（42例）和SE_LOW组（45例）;评价图像质量,分析主观评分的观察者间一致性;比较3组扫描长度、扫描时间、剂量长度乘积（DLP）、容积CT剂量指数（CTDIvol）和有效剂量（ED）,以及各组非PE患者肺动脉干及各段肺动脉CT值、平均肺动脉信号噪声比（SNR）和对比噪声比（CNR）、肺动脉与邻近血管（各段肺静脉及上腔静脉、主动脉）相对密度比及肺动脉栓子分布的差异。结果 各组图像质量主观评分均以2、3级为主,未见0级病例。DE组检查时间长于SE组和SE_LOW组（P均<0.05）,SE_LOW组ED显著低于DE组和SE组（P均<0.001）,后2组差异无统计学意义（P<0.05）。SE_LOW组非PE患者肺动脉CT值高于DE组和SE组（P均<0.05）,后2组之间差异无统计学意义（P>0.05）;SE_LOW组SNR和CNR均高于SE组（P均<0.05）,DE组与SE组差异均无统计学意义（P>0.05）。3组肺动脉与邻近血管相对密度比差异均无统计学意义（P均>0.05）。对47例PE共检出262个栓子,包括DE组17例112个、SE组11例64个及SE_LOW组19例86个;使用DE Vessels&PBV亚组对肺段以下肺栓子的检出率高于不使用亚组（P<0.05）。结论 SE_LOW CTPA的 SNR和CNR较高,辐射剂量较低,能满足诊断PE需求;DE CTPA对诊断肺段以下PE具有重要价值。     

CT诊断肺动脉高压Meta分析

目的 采用Meta分析评价CT在肺动脉高压中的诊断价值。方法 通过检索Pubmed、Elsevier和中国期刊网数据库(CNKI),获得相关中、英文文献,采用QUADAS-2工具对纳入的研究进行质量评价。采用Meta-disc 1.40软件对纳入的文献进行异质性检验,根据随机效应模型,汇总敏感度、特异度,并绘制综合受试者工作特征(SROC)曲线,计算曲线下面积。结果 共12篇文献符合要求,纳入其中8篇文献、均以肺动脉直径/升主动脉直径>1或≥1作为肺动脉高压的诊断标准,纳入对象共计1111例。Deeks漏斗图分析提示各文献间无明显发表偏倚(P=0.501)。汇总后的敏感度、特异度分别为74%(95%可信区间:70%~77%)、81%(95%可信区间:76%~85%),SROC曲线下面积为0.8535。结论 CT检查肺动脉直径/主动脉直径诊断肺动脉高压具有一定的临床应用价值。     

CTPA在诊断肺动脉血栓栓塞症中的临床价值研究

目的 探讨螺旋CT肺动脉造影(Computed tomography pulmonary angiography,CTPA)在诊断肺动脉血栓栓塞症(PTE)中的临床应用价值.方法 回顾性分析2006年7月至2008年10月经CTPA诊断的8例肺动脉血栓栓塞患者的CT征像.结果 8例经CTPA确诊的PIE病例,共累及86支肺动脉(51.1%).受累肺动脉位于右肺56支(65.1%),肺段动脉受累58支(67.4%).栓子形态包括完全充盈缺损16支,中心充盈缺损18支,偏心性部分充盈缺损39支,附壁充盈缺损13支.PE的间接征象主要包括肺动脉高压、肺梗死灶形成、胸腔积液和支气管动脉扩张等.结论 螺旋CT进行CTPA检查具有快捷、无创、安全等特点,是诊断肺动脉血栓栓塞症(FIE)的首选检查.     

双源双能量CT诊断周围型肺动脉栓塞的价值

目的 探讨双源双能量CT对周围型肺动脉栓塞的诊断价值.方法 从临床怀疑肺动脉栓塞(PE)并行双源双能量CT肺动脉成像的患者中选择周围型PE患者36例(98个栓子)纳入本研究.运用Syngo.via工作站对双源双能量CT扫描数据进行CT肺动脉血管成像(CTPA)和CT双能量Lung Analysis后处理.记录PE的栓塞...     

Chinese multi-center study of lung scintigraphy and CT pulmonary angiography for the diagnosis of pulmonary embolism

To evaluate diagnostic value of the PISA-PED and PIOPED II criteria for lung scintigraphy and compare it with CT pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE). Five hundred and forty-four consecutive patients with suspected PE were enrolled. All patients underwent lung ventilation/perfusion (V/P) scan, chest radiography, and CTPA. Two readers used the PIOPED II criteria, and 2 used the PISA-PED criteria for the interpretation of lung scintigraphy. CTPA scans were interpreted by two experienced radiologists. Lung scintigraphy and CTPA were categorized as PE present, absent or non-diagnostic. PE was present in 321 of 544 patients. Using PIOPED II criteria, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 85.1, 82.5, 88.1, and 78.4% respectively for V/P scan. Using PISA-PED criteria, sensitivity, specificity, PPV, and NPV were 86.0, 81.2, 86.8, and 80.1% respectively, and none was non-diagnostic. Sensitivity, specificity, PPV, and NPV were 81.7, 93.4, 94.9, and 77.3%, respectively for CTPA. PISA-PED interpretation has similar diagnostic accuracy to PIOPED II interpretation, does not have non-diagnostic scan, with lower cost and radiation, thus should be considered as a choice for patients with suspected PE.     

Ordering CT pulmonary angiography to exclude pulmonary embolism: defense versus evidence in the emergency room

Purpose

To identify reasons for ordering computed tomography pulmonary angiography (CTPA), to identify the frequency of reasons for CTPA reflecting defensive behavior and evidence-based behavior, and to identify the impact of defensive medicine and of training about diagnosing pulmonary embolism (PE) on positive results of CTPA.

Methods

Physicians in the emergency department of a tertiary care hospital completed a questionnaire before CTPA after being trained about diagnosing PE and completing questionnaires.

Results

Nine hundred patients received a CTPA during 3?years. For 328 CTPAs performed during the 1-year study period, 140 (43?%) questionnaires were completed. The most frequent reasons for ordering a CTPA were to confirm/rule out PE (93?%), elevated D-dimers (66?%), fear of missing PE (55?%), and Wells/simplified revised Geneva score (53?%). A positive answer for “fear of missing PE” was inversely associated with positive CTPA (OR 0.36, 95?% CI 0.14–0.92, p?=?0.033), and “Wells/simplified revised Geneva score” was associated with positive CTPA (OR 3.28, 95?% CI 1.24–8.68, p?=?0.017). The proportion of positive CTPA was higher if a questionnaire was completed, compared to the 2-year comparison period (26.4 vs. 14.5?%, OR 2.12, 95?% CI 1.36–3.29, p?p?=?0.067).

Conclusion

Reasons for CTPA reflecting defensive behavior—such as “fear of missing PE”—were frequent, and were associated with a decreased odds of positive CTPA. Defensive behavior might be modifiable by training in using guidelines.     

Computed tomography pulmonary angiography in the diagnosis of acute pulmonary embolism in the emergency department

This study was undertaken to evaluate the use of computed tomography pulmonary angiography (CTPA) in patients with pulmonary embolism (PE) who were followed in the emergency department (ED). The files and computer records of 850 patients older than 16 years of age who were seen in the Hacettepe University Hospital ED between April 10, 2001, and December 1, 2005, and who required CTPA for PE prediagnosis and/or another diagnosis, were studied retrospectively. PE was identified by CTPA in 9.4% of 416 women and in 5.8% of 434 men. A significant difference (P< .05) was noted in the women and men in whom PE was detected. The mean age of the patients was 58.13±17.88 y (range, 16–100 y). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for clinical susceptibility to PE among patients who underwent CTPA were assessed at 95.3%, 48.2%, 13%, and 99.2%, respectively. CTPA was done for different reasons: aortic aneurysm dissection (n=1), cough distinctive diagnosis (n=1), dyspnea distinctive diagnosis (n=6), chest pain distinctive diagnosis (n=3), PE prediagnosis (n=51), and other reasons (n=2). Also, sensitivity, specificity, PPV, and NPV were found to be 95.4%, 16.2%, 14.4%, and 96%, respectively, for D-dimer. CTPA, which is accessible on a 24-h basis in the ED, is a valuable tool for the diagnosis of PE.     

计算机辅助检测技术辅助低年资医师诊断急性肺栓塞的诊断效能

目的 评价计算机辅助检测(CAD)技术提高低年资医师在CT肺血管造影(CTPA)检查中诊断急性肺栓塞能力的价值.方法 连续收集2010年7-12月间接受CTPA检查的可疑肺栓塞或下肢深静脉血栓患者.以3名高年资放射科医师做出的一致性诊断作为参考标准,另由2名缺乏经验的低年资医师(低年资医师组)共同记录栓子的位置、数目.3个月后,此2名低年资医师借助CAD(低年资医师+CAD组)对患者重新进行评估.分别从患者数和栓子数两方面比较低年资医师组和低年资医师+CAD组诊断急性肺栓塞的差异.结果 共267例患者纳入研究.高年资医师诊断急性肺栓塞患者81例,检出栓子555个.低年资医师组检出患者67例,栓子493个,在肺动脉各级(肺动脉主干、叶、段、亚段)的敏感度分别为100％(26/26)、98.63％ (72/73)、89.76％ (228/254)和82.67％(167/202),特异度分别为100％(775/775)、99.80％(1526/1529) 、99.55％(5063/5086)和99.50％ (10426/10478);低年资医师+CAD组检出患者75例,栓子523个,在肺动脉各级的敏感度分别为100％(26/26)、100％(73/73)、92.12％(234/254)和94.06％(190/202),特异度分别为100％(775/775)、99.74％(1525/1529)、99.47％(5059/5086)和99.32％(10407/10478).结论 借助于CAD,低年资医师诊断肺栓塞的准确性得到显著提高,尤其是对于检出亚段肺动脉栓子.     

A novel ECG parameter for diagnosis of acute pulmonary embolism: RS time: RS time in acute pulmonary embolism

ObjectivesPulmonary embolism (PE) is one of the leading causes of cardiovascular mortality worldwide. Electrocardiography (ECG) may provide useful information for patients with acute PE. In this study, we aimed to investigate the diagnostic value of the QRS duration and RS time in inferolateral leads in patients admitted to the emergency department, and pre-diagnosed with acute PE.MethodsWe retrospectively enrolled 136 consecutive patients, admitted to the emergency department, pre-diagnosed with the clinical suspicion of acute PE, and underwent computerized tomographic pulmonary angiography (CTPA) to confirm the PE diagnosis. The study subjects were divided into two groups according to the presence or absence of PE, and the independent predictors of PE were investigated.ResultsSixty-eight patients (50%) had PE. Patients with PE had a longer RS time. Among the ECG parameters, only RS time was an independent predictor of PE (OR: 1.397, 95% CI: 1.171–1.667; p < 0.001). The ROC curve analyses revealed that the cut-off value of RS time for predicting acute PE was 64.20 ms with a sensitivity of 85.3% and a specificity of 79.4% (AUC: 0.846, 95%CI: 0.749–0.944; p < 0.001). In the correlation analyses; the RS time was correlated with RV end-diastolic diameter (r = 0.422; p < 0.001), RV/left ventricle (LV) ratio (r = 0.622; p < 0.001), and systolic pulmonary artery pressure (SPAP) (r = 0.508; p < 0.001).ConclusionAs a novel ECG parameter, RS time could be measured for each patient. A longer RS time can be a very useful index for diagnosing acute PE as well as for estimating the RV end-diastolic diameter and SPAP.     

Assessing 2 d-dimer age-adjustment strategies to optimize computed tomographic use in ED evaluation of pulmonary embolism

Study ObjectiveValidate the sensitivity and specificity of 2 age adjustment strategies for d-dimer values in identifying patients at risk for pulmonary embolism (PE) compared with traditional d-dimer cutoff value (500 ng/mL) to decrease inappropriate computed tomography pulmonary angiography (CTPA) use.MethodsThis institutional review board–approved, Health Insurance Portability and Accountability Act-compliant retrospective study included all adult emergency department patients evaluated for PE over a 32-month period (1/1/11–8/30/13). Only patients undergoing CTPA and d-dimer testing were included. We used a validated natural language processing algorithm to parse CTPA radiology reports and determine the presence of acute PE. Outcome measures were sensitivity and specificity of 2 age-adjusted d-dimer cutoffs compared with the traditional cutoff. We used χ² tests with proportional analyses to assess differences in traditional and age-adjusted (age × 10 ng/mL) d-dimer cutoffs, adjusting both by decade and by year.ResultsA total 3063 patients with suspected PE were evaluated by CTPA during the study period, and 1055 (34%) also received d-dimer testing. The specificity of age-adjusted d-dimer values was similar or higher for each age group studied compared with traditional cutoff, without significantly compromising sensitivity. Overall, had decade age-adjusted cutoffs been used, 37 CTPAs could have been avoided (19.6% of 189 patients aged > 60 years with Wells score ≤ 4); had yearly age-adjusted cutoffs been used, 52 CTPAs (18.2% of 286 patients aged > 50 years with Wells score ≤ 4) could have been avoided.ConclusionEach age-adjusted d-dimer cutoff strategy for the evaluation of PE was associated with increased specificity and statistically insignificant decreased sensitivity when compared with the traditional d-dimer cutoff value.     

Increasing use of CTPA for the investigation of suspected pulmonary embolism

Objectives: Pulmonary embolism (PE) is a frequently suspected life-threatening condition that often presents with non-specific signs and symptoms. There is concern that increased availability of computerized tomography pulmonary angiogram (CTPA) is resulting in overuse in the diagnostic workup of patients presenting with cardio-respiratory symptoms. We therefore aimed to determine whether use of CTPA was increasing over time within our institution, with a consequent decrease in the diagnostic yield of PE. Furthermore, we investigated the frequency of alternative (non-PE) pathological findings revealed by CTPA.

Methods: All patients who underwent CTPA in the first 15 days of eight consecutive years were enrolled retrospectively. Radiology reports and online medical records were examined. In addition, the rates of incidental PE from patients undergoing CT chest for non-suspected PE indications were also examined.

Results: An increasing use of CTPA was confirmed (p = 0.04). Despite this, the diagnostic yield of PE also increased (p = 0.03). Similarly, increasing numbers of patients underwent CT chest for non-PE indications, but in this group the rate of incidental PE remained static (~3.4%). In CPTA investigations that were negative for PE, common alternative findings were consolidation, pleural effusion and emphysema, with only 16.7% showing no abnormality.

Conclusion: Although CTPA use is increasing, so is the diagnostic yield of PE. In contrast, the rate of incidental PE in those undergoing a CT chest scan for non-PE diagnosis remains relatively low and stable. This suggests that our observed increased use of CTPA is clinically appropriate.