Transcutaneous colour Doppler sonography of lung consolidations: review and pictorial essay. Part 1: pathophysiologic and colour Doppler sonographic basics of pulmonary vascularity

Anatomically, the lung is characterised by a dual blood supply. The existence of a systemic bronchial arterial supply to the lung in addition to the pulmonary arteries was first described by Galen in the second century. From angiographic studies it is known that pulmonary lesions of different aetiologies are characterised by differences in arterial supply. Colour Doppler sonography makes it possible to classify pulmonary arteries by location, flow direction, and quantitative spectral curve analysis. This article will review pathophysiological and colour Doppler sonographic basics of pulmonary vascularity.     

Three-dimensional power Doppler vascular sampling: a new method for predicting ovarian cancer in vascularized complex adnexal masses.

OBJECTIVE: The purpose of this study was to explore the role of a new concept ("vascular sampling") as a third step to discriminate benign and malignant lesions in B-mode and color Doppler sonographically suggestive adnexal masses. METHODS: Forty-five women (mean age, 52.3 years; range, 17-82 years) with the diagnosis of complex adnexal masses on B-mode sonography were evaluated using 3-dimensional power Doppler sonography. Four women had bilateral masses. After a morphologic reevaluation was done, color pulsed Doppler sonography was used to obtain flow velocity waveforms, and velocimetric indices were calculated (resistive index, pulsatility index, and peak systolic velocity). Thereafter, 3-dimensional power Doppler sonography was used to assess vascularization of highly suggestive areas (gross papillary projections, solid areas, and thick septations), meaning a focused assessment ("sampling") of a suggestive area of the tumor. With a virtual organ computer-aided analysis program, vascular indices (vascularization index, flow index, and vascular flow index) were automatically calculated. A definitive histologic diagnosis was obtained in each case. RESULTS: Forty masses (82%) were malignant and 9 (18%) were benign. Morphologic evaluation revealed 10 (20%) unilocular solid masses, 20 (41%) multilocular solid masses, and 19 (39%) mostly solid masses. Blood flow was found in all cases. Median vascularization index (15.5% versus 8.2%; P = .002), flow index (33.6 versus 20.8; P = .007), and vascular flow index (5.2 versus 2.3; P = .001) were significantly higher in malignant tumors. No differences were found in resistive index (0.43 versus 0.45; P = .770), pulsatility index (0.62 versus 0.65; P = .694), and peak systolic velocity (15.6 versus 12 cm/s; P = .162). CONCLUSIONS: Three-dimensional power Doppler vascular sampling seems to be a promising tool for predicting ovarian cancer in vascularized complex adnexal masses. It could be better than conventional color pulsed Doppler imaging.     

Effects of hypertension and antihypertensive treatment on retrobulbar circulation detected on Doppler sonography.

OBJECTIVE: To study the effect of antihypertensive drugs in essential hypertension and in the central retinal, posterior ciliary, and ophthalmic arteries by using Doppler sonography. METHODS: Thirty patients with essential hypertension and 32 control subjects were enrolled in the study. The pulsatility and resistive indices were evaluated in the central retinal, posterior ciliary, and ophthalmic arteries before and 2 months after treatment with antihypertensive drugs as well as in the control group. The pulsatility and resistive index values for each artery in each group were compared statistically. RESULTS: There were significant differences in the retrobulbar pulsatility and resistive index values in each artery among the patients with initially diagnosed hypertension and the control group (P < .05). There were significant reductions in the resistive and pulsatility index values of the posterior ciliary and ophthalmic arteries after treatment (P < .05). For the ophthalmic artery, posttreatment pulsatility and resistive index values did not reach the level of flow measured in the control subjects. CONCLUSIONS: The alteration of Doppler parameters of medication-free patients with hypertension may result from a peripheral vasospasm in the retrobulbar circulation, and the improvement in the Doppler parameters with oral antihypertensive drugs may indicate the importance of early diagnosis in ameliorating hypertension-induced retrobulbar circulation changes.     

Power Doppler imaging and evaluation of the resistive index in focal nodular hyperplasia of the liver

Focal lesions of the liver represent a significant diagnostic problem for various imaging modalities. The aim of this study was to assess the value of power Doppler sonography versus conventional color Doppler imaging in the depiction of hypervascular focal nodular hyperplasia (FNH) of the liver and to investigate the resistive index (RI) in the lesions' feeding arteries. Eighteen histologically proved FNHs in 14 patients were evaluated by gray-scale ultrasound, conventional color Doppler, and power Doppler sonography. With conventional color Doppler, a feeding arterial vessel could be depicted in only 4/18 lesions and hypervascularization was detected in 6/18 lesions. Power Doppler was more sensitive in detecting feeding arteries (16/18) within hypervascular lesions (15/18). RI values in the feeding arteries (mean = 0.51) significantly differed from those in the main hepatic artery or its intraparenchymal branches (mean = 0.68) in the same patient. The mean RI-difference was 0.19, suggesting hemodynamically significant arteriovenous shunting. Power Doppler sonography significantly increases sensitivity in the diagnosis of focal nodular hyperplasia of the liver and reliably permits the distinction of these lesions from hepatocellular carcinomas. Received: 17 January 1996/Accepted after revision: 8 May 1996     

Normal uterine arterial blood flow in postmenopausal women assessed by transvaginal color Doppler ultrasonography.

We used transvaginal color Doppler sonography to study uterine artery blood flow velocity waveforms in 345 normal postmenopausal women who had never been on hormone replacement therapy. Our objective was to establish the standard baseline flow values for normal postmenopausal women. The mean pulsatility index was 3.38 +/- 1.04 and the mean resistive index was 0.93 +/- 0.09. There was a positive correlation between arterial blood flow impedance and number of years since menopause. We believe that these levels may become important screening parameters for the detection of endometrial carcinoma in postmenopausal women.     

Transcranial color Doppler imaging of brain arteriovenous malformations in adults

This study was performed to investigate the utility of transcranial color Doppler sonography in evaluating adult cerebral arteriovenous malformations. Twelve patients with such malformations underwent sonography. Spectral Doppler sonographic assessment included peak systolic velocity, end diastolic velocity, and resistive index within the intracranial and extracranial vessels. Color Doppler sonography was used to visualize the site of shunting. Paired and unpaired Student's t-tests were used to determine significance of spectral findings. The nidus was seen in eight of 10 pial malformations. The nidi in two patients were located in the parietal region and not visualized. When compared with the corresponding contralateral artery, feeding arteries (identified in all 10 of the pial lesions) demonstrated diminished resistive indices (P = 0.09). Similarly, the end diastolic velocity was increased in all feeding arteries (P = 0.03). When compared with published normal values, the peak systolic and end diastolic velocities were significantly elevated and the resistive indices were low (P < 0.0003). Transcranial color Doppler sonography depicted the nidi of pial arteriovenous malformations in 80% of cases. Feeding arteries demonstrated abnormal peak systolic velocity, end diastolic velocity, and resistive index in all cases when compared with published values. Transcranial color Doppler sonography is not a good screening tool due to limited acoustical window, but it may be useful for noninvasive study of the physiology of arteriovenous malformations as they are treated.     

Color Doppler sonographic assessment of placental circulation in the first trimester of normal pregnancy.

Our aim was to study placental circulation during the first trimester of normal pregnancy. For this purpose, 108 single pregnancies from 4 to 15 gestational weeks were evaluated through conventional Doppler ultrasonography. The flow velocity waveforms from the retrochorionic arteries (spiral-radial arteries) and the umbilical artery were assessed using the peak systolic velocity, resistive index, and pulsatility index). Intervillous flow velocity waveform was evaluated from the maximum velocity. The earliest color signal from the retrochorionic circulation was registered at 4.5 weeks along with gestational sac visualization. The venous Doppler signal from the intervillous space and the Doppler signal from the umbilical artery were recorded with an embryo visible from the end of week 5 onward. The retrochorionic, intervillous, and umbilical peak systolic velocities increase, whereas the resistive and pulsatility indices decrease progressively during early pregnancy with a significant correlation with gestational age. Similarly, intervillous maximum velocity gradually increases throughout the first trimester of pregnancy. Despite some methodologic problems related to Doppler technology and the vessels studied color Doppler sonography appears to be an adequate tool to assess the physiologic changes in the placental circulation during early pregnancy.     

Complex adnexal mass in pregnancy: predictive value of color Doppler sonography.

We sought to establish color Doppler sonographic criteria specific to benign and malignant neoplasms in pregnant patients for parameters already reported for complex adnexal masses in nongravid patients. Thirty-four patients with complex adnexal masses were evaluated during the second trimester with transabdominal sonography and transvaginal color Doppler sonography. The lowest pulsatility index obtained was chosen to be indicative of histologic type. A pulsatility index of less than 1.0 in a morphologically suspect area was taken to be suggestive of malignancy. Prospective diagnoses made by color Doppler sonography were compared with actual histologic diagnosis. Three malignant ovarian lesions and five tumors of low malignant potential were identified correctly, with a sensitivity of 0.89 and a mean pulsatility index of 0.71 (range, 0.44 to 1.3). The mean pulsatility index for benign masses was 1.21 (range, 0.4 to 2.8) (P = 0.03). The negative predictive value of a pulsatility index greater than 1.0 was 0.93. The positive predictive value and false-positive rate for a pulsatility index less than 1.0, however, were 0.42 and 0.48, respectively. Low impedance was associated with malignant ovarian masses detected during pregnancy. A considerable overlap in blood flow patterns, however, may cause incorrect assignment of malignant potential to some benign lesions.     

Color Doppler US pulmonary artery vessel signal: a sign for predicting the benign lesions

The lung cancer blood supply originates from the bronchial artery. If vessel signals within pulmonary lesions can be confirmed to be those of the pulmonary artery, color Doppler ultrasound (US) should be able to predict and differentiate benign lesions from lung cancers. Two hundred sixty-four patients with abutting thoracic lesions (including 125 lung cancers and 139 benign lesions) underwent color Doppler US examinations. A pulsatile flow, with the vessel signal length on sonographic appearance > or =1 cm demonstrated by color Doppler US, was arbitrarily defined as a pulmonary artery vessel signal. Of the 264 thoracic lesions, 73 (58%) lung cancers and 107 (77%) benign lesions had detectable color Doppler US pulsatile flow vessel signals. Analyzing the pulsatile flow vessel signals, the color Doppler US pulmonary artery vessel signal was present in 74 (53%) benign lesions, but was found in only two (2%) lung cancers of a specific alveolar cell carcinoma with lobar consolidation. Using the pulmonary artery vessel signal, color Doppler US can be valuable in predicting and differentiating benign lesions from lung cancers (p < 0.0001, sensitivity = 0.53, specificity = 0.98 and positive likelihood ratio 26.5). In conclusion, color Doppler US pulmonary artery vessel signal sign is useful in predicting and differentiating benign lesions from lung cancers.     

Transvaginal gray scale and color Doppler sonography in primary ovarian cancer and metastatic tumors to the ovary.

OBJECTIVE: To compare gray scale and color Doppler features of primary and metastatic ovarian carcinomas. METHODS: Clinical, sonographic (gray scale and color Doppler), and histopathologic data of 143 patients with primary (n = 127 adnexal masses) and metastatic (n = 34 adnexal masses) ovarian cancer were reviewed. Morphologic gray scale parameters assessed were bilaterality, tumor volume, echogenicity, and presence of septa, papillary projections, or solid areas. Color Doppler parameters were presence of blood flow, tumor blood flow location (central versus peripheral), subjective impression of blood flow amount (scanty, moderate, or abundant), lowest resistive index, lowest pulsatility index, and maximal peak systolic velocity (centimeters per second). RESULTS: No statistical differences were found in bilaterality, tumor volume, presence of septa, papillary projections or solid areas, presence of blood flow, tumor blood flow location, subjective impression of blood flow amount, lowest resistive index, lowest pulsatility index, and maximal peak systolic velocity. Metastatic carcinomas were more frequently purely solid tumors (47% versus 26%; P = .001; likelihood ratio, 2.4; 95% confidence interval, 1.2-4.7). CONCLUSIONS: The presence of a purely solid tumor indicates a higher probability of metastatic carcinoma than primary ovarian cancer. However, with the use of gray scale and color Doppler sonography, it is difficult to differentiate primary ovarian carcinomas from metastatic tumors to the ovary.     

Bronchioloalveolar carcinoma: sonographic pattern of 'pneumonia'.

BACKGROUND: the sonographic pattern of bacterial pneumonia is predominantly well known and characterized by an air bronchogram, a marked vascularity on color Doppler sonography, and a high-impedance arterial flow pattern on Doppler spectral analysis. METHODS: in a retrospective study the sonographic findings in seven patients with peripheral BAC on X-ray examination were evaluated in relation to number, size, margins, echomorphology and sonographic arterial flow patterns of the lesions. RESULTS: the following sonomorphologic characteristics were found: multiple foci (n=4), single foci (n=3), smooth margins (n=5), irregular margins (n=2) and maximal diameter of size (range 5-15 cm). The echomorphology of the lesions was homogenously hypoechoic (n=1) or showed airbronchograms (n=6). Color Doppler sonography revealed a vascular tree pattern (n=5) or a marked presence of blood vessels (n=2). Doppler flow spectral analysis of arteries in investigated patients (n=5) demonstrates a high impedance (triphasic) flow pattern in four patients and a low impedance (monophasic) flow pattern in one patient. CONCLUSIONS: these findings indicate that BAC frequently shows a sonographic pattern of 'pneumonia'.     

肉芽肿性小叶性乳腺炎的灰阶及彩色多普勒超声显像

目的回顾性分析肉芽肿性小叶性乳腺炎的灰阶和彩色多普勒超声表现，力求为这种少见的疾病提供诊断依据。方法12例手术病理证实的患者全部经过超声检查，先用二维观察肿块的部位、形态、大小等，再用彩色多普勒血流成像（CDFI）探测，按照Adler半定量方法进行血流分级，用频谱多普勒测量血管最高流速（PSV）、阻力指数（RI）、搏动指数（PI）。结果灰阶超声可分三型：（1）不规则低回声肿块，5例。（2）低回声结节，4例。（3）混合回声型，3例。CDFI探查，大部分病例病灶内血流较丰富；频谱测量，PSV8～22cm／s，平均（15±6）cm／s；P10．8～1．6，平均1．2±0．3；R10．51～0．79，平均0．65±0．14，测值范围较宽，无特异性。结论灰阶超声对肉芽肿性小叶性乳腺炎的诊断起着重要的作用，彩色血流显示较丰富，频谱分析未见明显的特异性。     

子宫动脉栓塞术治疗子宫肌瘤的早期血流动力学变化

目的探讨子宫肌瘤子宫动脉栓塞(UAE)后的血流动力学变化。方法选择30例子宫肌瘤经腹部彩色多普勒和MR诊断的患者予双侧子宫动脉栓塞(UAE),分别于栓塞前1周内和栓塞后7天、1个月予彩色多普勒超声检查,测量双侧子宫动脉血流量(BFV),搏动指数(PI)、阻力指数(RI)和平均流速(Vm),并用能量图(CDE)观察血流情况。结果2组病例栓塞前与栓塞后7天、1个月比较,BFV、PI、RI、Vm均明显减少,P＜0.01;栓塞后7天和1个月子宫肌层和肌瘤周边血流明显减少或未见显示。结论UAE治疗在早期对病灶血流的阻断是持续存在的,从而保证了栓塞治疗的疗效。     

Hemodynamic factors affecting uterine artery Doppler waveform pulsatility in sheep.

Quantitative analysis of vascular resistance from the Doppler time-velocity waveform relies on measuring arterial pulsatility. However, input pressure waveform pulsatility, impedance, and resistance have all been found to effect artery flow waveform pulsatility in circulatory mathematic models and in umbilical sheep preparations in vivo. The present study used an in vivo sheep preparation to determine that embolization of the uteroplacental circulation and maternal angiotensin II administration caused changes in the uterine Doppler time-velocity waveform pulsatility that were dependent on input pressure waveform pulsatility, fundamental impedance, and resistance changes. Uteroplacental vascular embolization increased vascular resistance and the uterine artery Doppler waveform resistive index; the mean component of flow (mean pressure/resistance) decreased. Decreased uterine artery Doppler resistive index occurred despite angiotensin II-induced vasoconstriction and increased vascular resistance because the pulse component of flow (pulse pressure/impedance) decreased.     

The characterization of flow signals from tubal and ovarian arteries using intraoperative continuous wave Doppler.

Ovarian vascular Doppler is a promising screening test for early ovarian cancer detection. However, disagreements on flow indices used, flow signal shapes and ovarian vessel localization cause continuing controversy. We aimed at clarifying some of this confusion by directly measuring the adnexal arterial blood flow during laparotomy. A 10-MHz continuous Doppler probe was used to examine adnexal vessels in 24 patients undergoing laparotomy for benign gynecological pathology. Resistance (RI) and pulsatility (PI) indices were calculated for each vessel and the shape of the flow signals was noted. The tubal arteries showed a low-velocity flow pattern with relatively high end-diastolic flow when compared to the ovarian artery signals obtained from the infundibulopelvic ligament.The mean RIs for the tubal artery and ovarian artery in the infundibulopelvic ligament were 0.59 +/- 0.02 and 0.73 +/- 0.02, respectively. The mean PIs for the tubal and ovarian artery in the infundibulopelvic ligament were 1.11 +/- 0.09 and 1.53 +/- 0.1, respectively. The tubal artery showed a significantly lower RI and PI when compared to the ipsilateral ovarian artery at the infundibulopelvic ligament (p < 0.001 and p = 0.002, respectively) and its hilar branches (p = 0.03 for RI and p = 0.03 for PI). We conclude that tubal artery flow signals, which are measured directly for the first time in this study, are characteristic and are distinct from the ovarian artery signals. Tubal artery signals might be erroneously picked up during transvaginal color Doppler sonography of the ovaries, especially in the presence of conditions causing a decreased impedance to blood flow in the pelvis, such as ovarian tumors. Recognizing the flow signal from the tubal artery may help in differentiating ovarian and tubal vessels detected during color Doppler sonography.     

Alterations in segmentary branch pulmonary artery blood flow velocimetry in fetuses of diabetic mothers.

OBJECTIVE: To evaluate pulmonary blood flow in fetuses of diabetic mothers by measuring changes in fetal segmentary pulmonary artery blood flow velocimetry throughout pregnancy. METHODS: Thirty-eight women with pregestational diabetes between weeks 18 and 38 were compared with 99 women with singleton low-risk gestations as controls. Flow velocity waveforms at the proximal middle and distal segments of the right pulmonary artery were obtained with power and color Doppler sonography in all fetuses. The pulsatility index of each segment was compared between the 2 groups. The mean value and 95% confidence interval for each segment were determined in correlation with gestational age for both groups. RESULTS: The highest mean pulsatility indices were obtained in the proximal segment of the pulmonary artery and were 2.25 in the diabetes group and 2.36 in controls. The mean pulsatility indices were significantly decreased in the middle and distal segments to 1.59 and 1.10 in the diabetes group and to 1.57 and 1.02 in controls (P < .05). There were no significant differences in pulsatility indices measured at the proximal and middle segments between the study and control groups. However, the mean pulsatility index +/- SD measured at the distal segment in the diabetic group was 9% higher than in controls (1.10 +/- 0.13 versus 1.02 +/- 0.12; P = .01). The mean pulsatility index (in the study and control groups) in each arterial segment did not change significantly throughout gestation (P > .1). CONCLUSIONS:. In human fetuses throughout gestation, the pulmonary circulation maintains stable vascular resistance in both diabetic and normal pregnancies. However, in all gestations, the pulsatility index in each segment of the pulmonary artery is unique and reflects the proximity to the heart and the impedance at each location. The significantly higher pulsatility index in the diabetes group might be related to alterations in the microcirculation of diabetic patients.     

Validity of pulsatility and resistance indices in classification of adnexal tumors with transvaginal color Doppler ultrasound.

Transvaginal pulsed color Doppler ultrasound was used to examine 72 patients with a pelvic mass preoperatively. Tumor morphology was assessed, prominent areas of vascularization within the tumor were observed and the pulsatility index and the resistance index of tumor and uterine arteries were measured. Flow velocity waveforms with low pulsatility are considered to reflect neovascularization. The ultrasound diagnoses were compared with histopathological or cytological diagnoses. There were 61 benign, eight malignant and three borderline cases. In 75% of the malignant and 23% of the benign tumors, an intratumoral flow with a low pulsatility was detectable. The mean pulsatility index of tumor blood vessels was 1.2 in benign, 0.7 in malignant and 0.6 in borderline neoplasms. The corresponding mean resistance index values were 0.6, 0.5 and 0.5. The differences were not significant and the overlap between the malignant and benign lesions was large. The pulsatility index and resistance index of uterine arteries were significantly decreased in malignant tumors. The results show that, using a cut-off resistance index value of 0.6, the sensitivity and specificity of color Doppler in the detection of malignant and potentially malignant tumors were 82% and 72%, respectively. However, a practical cut-off level for either pulsatility or resistance indices, that could assist in differentiating between malignant or benign lesions, does not seem to exist.     

Color Doppler sonographic signs of respiration-dependent hepatofugal portal flow

PURPOSE: The role of respiration in modulating blood flow in the portal vein is unclear. The aim of this study was to investigate the phenomenon of respiration-dependent periodic hepatofugal portal venous blood flow as detected on color Doppler sonography. METHODS: Within 1 year, we identified 13 patients with respiration-dependent reversal of blood flow in the portal vein that was diagnosed on color Doppler sonography. This phenomenon was investigated by color Doppler sonographic examination of the portal venous flow during both mid-inspiration breath-holding and a respiratory cycle including deep inspiration; evaluation of hepatic vein Doppler waveforms as normal (triphasic) or decreased (flattened); and echocardiographic examination to determine the presence or absence of tricuspid regurgitation. RESULTS: The patients' median age was 53 years (range, 26-87 years). Seven of the 13 patients had heart disease (tricuspid regurgitation) with or without liver disease, 3 had liver disease without heart disease, and 3 had other diseases with no evidence of heart or liver disease. On Doppler sonography, 10 of the 13 patients had increased portal venous pulsatility (7 of the 10 had tricuspid regurgitation; the other 3 did not); the remaining 3 patients had neither increased pulsatility nor tricuspid regurgitation. Sonographic follow-up within 4 weeks in 4 of the 13 patients revealed loss of the respiration-dependent hepatofugal portal flow. CONCLUSIONS: Respiration-dependent hepatofugal portal flow is a rare finding associated with periodic portal hypertension in patients with right heart insufficiency and liver disease. Its clinical significance is unclear. Among our patients, its occurrence was predominantly associated with an increased venous pulsatility index due to tricuspid regurgitation or venous outflow obstruction. Further study is needed to investigate whether periodic respiration-dependent hepatofugal portal flow is predictive of the occurrence of continuous flow reversal.     

A sign of arteriogenic insufficiency on penile Doppler sonography: retrograde flow in penile cavernosal-spongiosal communications.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic usefulness of determining retrograde flow in the penile cavernosal-spongiosal communications (CSCs) with Doppler sonography. METHODS: Thirty-two consecutive men with erectile dysfunction (mean age, 40 years; range, 19-61 years) underwent penile color Doppler sonography. All patients were evaluated for flow direction in the CSCs. RESULTS: Eight of the 32 patients had normal Doppler sonographic findings; 8 had signs of veno-occlusive dysfunction; and 16 had arterial insufficiency. Doppler sonographic examinations of the patients with normal Doppler sonographic findings (100%) and veno-occlusive dysfunction (100%) showed a normal direction of flow in the CSCs. Thirteen of the 16 patients with arterial insufficiency had a normal direction of flow in the CSCs; however, reversal of the flow direction in the CSCs (from the urethral artery back to the cavernosal artery) was observed in the remaining 3 patients. CONCLUSIONS: Investigating the direction of flow in the cavernosal artery, CSCs, and urethral artery is not time-consuming and may help establish an accurate diagnosis of arteriogenic impotence, especially in patients with borderline peak systolic flow velocity values.     

多发性大动脉炎颈动脉病变的彩超特征

目的：研究多发性大动脉炎(TA)颈动脉病变的超声特征。方法：TA患者30例。彩超检查颈总、内、外动脉，观察颈动脉病变分布，测量颈总动脉内膜中层厚度；彩色血流显像(CFI)及脉冲多普勒(PD)分析颈动脉血流变化。结果：30例患者中53支颈总动脉受累，平均内膜中层厚度2．4mm。TA颈动脉病变多累及颈总动脉近端，较少直接累及颈内外动脉，但35支颈内和31支颈外动脉内仍表现为血流异常，出现低搏动性血流。23支(23／60，38％)颈外动脉血流反向，近端颈总动脉均有严重狭窄或闭塞。4支病变颈总动脉出现壁内动脉，提示TA处于活动期。结论：彩超可发现TA颈动脉病变较多特征，对诊断TA有重要作用。