多层螺旋CT肺结节和血管的关系

1、Multi-detector spiral CT study of the relationshipsbetween pulmonary ground-glass nodules and blood vesselsEur Radiol (2013) 23:32713277AbstractObjective : To investigate the relationships between pulmo-nary ground-glass nodules (GGN) and blood vessels and their diagnostic values in differentiating

2、GGNs.Conclusion : Different GGNs have different relationships with vessels. Understanding and recognising characteristic GGN-vessel relationships may help identify which GGNs are more likely to be malignant.Key Points Multi-detector CT offers new information about ground- glass nodules. Different ty

3、pes of ground-glass nodules have different relationships with vessels.This may help identify which ground-glass nodules are likely to be malignant.Introduction With the extensive acceptance of low-dose multi-detector spiral CT in lung cancer screening , the number of detected GGNs or focal ground-gl

4、ass opacities (fGGOs) has dramatically increased. GGNs can result from neoplasms, such as pulmonary adenocarcinoma, or benign diseases, such as focal fibrosis, inflammation or alveolar haemorrhage.In addition, pre-invasive abnormalities, including atypical adenomatous hyperplasia (AAH) and adenocarc

5、inoma in situ (AIS). It has been reported that the proportion of malignancy in GGNs is higher than in solid pulmonary nodules (SPNs) and the majority of malignant GGNs are adenocarcinoma . Due to imaging resemblance, however, it is extremely challenging to differentiate malignant GGNs from the afore

6、mentioned benign counterparts. Accurate differential diagnosis of GGNs will assist physicians to make treatment decisions and improve treatment outcomes and prognosis. Several investigators have suggested that analysis of relationships between SPNs and surrounding vessels can help predict the likeli

7、hood of malignancy in such nodules. The relationship between GGNs and blood vessels remains unknown. Whether this relationship can be utilised to facilitate the diagnosis of malignant GGNs is a worthy of investigation. Materials and methods PatientsThe imaging data of patients with pulmonary GGNs re

8、ceiving thin-section multi-detector CT examination at our hospital in January 2011 through November 2012 were retrospectively reviewed.All lesions were solitary and most of them(104/108) surgically resected within 2 weeks after CT scanning. Inclusion criteriaThe GGN size was less than 3cm in the lar

9、gest dimension. ground-glass opacity (GGO) comprised more than 50 % of the area of the lesion on CT. -An area of over 50 % GGO was set as the cutoff value to exclude solid/semi-solid lesions. -Although solid nodules frequently had GGO components around their margin, probably representing surrounding

10、 oedema or merely poor aeration of the surrounding lung tissues due to compression or retraction by nodules, these nodules had already been well investigated using CT and therefore were not the study objects Ultimately, 108 patients were enrolled into this study, including 38 males and 70 females wi

11、th mean age of 58.1812.89 years (range, 22 to 79 years). 43 patients were asymptomatic, 28 had respiratory symptoms, and 37 had lung cancer risk factors, such as smoking and family history. According to pathological findings, GGNs were divided into three groups:Benign disease group (10 cases), inclu

12、ding four nodules diagnosed with a combination of clinical symptoms and imaging presentations (nodules disappeared or gradually reduced in size on multiple follow-up CT imaging) and six nodules confirmed by pathological examination (1 case of sclerosing haemangioma and 5 cases of chronic inflammatio

13、n).(2) Preinvasive disease group (24 cases), including 7 AAHs and 17 AISs.(3) the invasive adenocarcinoma group (74 cases), confirmed pathologically, there were 39 non-mucinous minimally invasive adenocarcinomas (MIA) and 35 invasive adenocarcinomas (IAC; specifically, 13 lepidic predominant adenoca

14、rcinomas; 19 acinus-predominant adenocarcinomas; 2 papillary-predominant adenocarcinomas and 1 solid predominant with mucin粘蛋白 production).CT imaging analysisprotocol parameters: 0.625-mm section width with a 0.625-mm reconstruction interval, pitch of 0.984, 120 kV and 250 mA. All images were review

15、ed with a high-resolution , 2,0481,560pixel ,standard lung window (ww , 1,500 HU; wl, -500 HU) and mediastinal window (ww, 350 HU; wl, 50 HU)GGNs can be further subdivided into mixed ground-glass nodules (mGGNs) and pure ground-glass nodules (pGGNs) . The percentage of the GGO component was calculat

16、ed as follows: (DGGO-D)/ DGGO 100, where DGGO is the largest diameter of the entire lesion and D is the largest diameter of the solid component within the lesion.Blood vessel analysis was performed in terms of vascular morphology and vascular relationships with GGN lesions.the diameter of pulmonary

17、vessels gradually decreases from the hilum toward the periphery. If the diameter of the vascular segment within lesions was larger than the proximal segment or lesion vessels were apparently wider than other vessels at the same branch level, the vessel was deemed as abnormal vascular broadening.The

18、vessels were considered to be distorted or rigid if traveling astray from the expected normal course.Multiple supplying vessels, with different originating sources, converging toward a lesion, were probably indicative of an increased blood circulation within. To further clarify affiliations of suppl

19、ying vessels, we traced vascular courses slice-wise backward to major vessels in the hilum . The relationships between the GGNs and supplying blood vessels were analysed in axial images, MPR images CPR images. the GGN-vessel relationships were categorized into four types according to imaging feature

20、s: type I (pass-by), vessels passed by GGNs without detectable supplying branches to lesions.type I type II (pass-through), vessels passed through the lesions without obvious morphological changes in traveling path or size . type III (distorted/dilated), vessels within lesions were tortuous or rigid

21、 without an increase in amount type IV (complicated), more complicated vasculature other than described in the aforementioned types within GGNs, for instance, coexistence of irregular vascular dilation and vascular convergence from multiple supplying vessels.Pathological analysisThe pathological dia

22、gnosis and categorisation of AAH, AIS, MIA and IAC were made based on the new pulmonary adenocarcinoma classification, 2011 edition . GGNs were resected by video-assisted thoracoscopy or thoracotomy surgery. All histological preparations and analyses were performed by two senior pathologists. In the

23、 case of disagreements, a consensus was reached after mutual discussion and/or consultation with a third pathologist.Statistical analysisSPSS 16.0 for Windows, SPSS, Chicago, IllIndependent t test was used to compare different pathological groups (benign diseases, preinvasive diseases and invasive a

24、denocarcinoma) of GGN.Correlations between pathological findings of GGNs and GGN-vessel relationships were examined using Spearmans rank test.GGN-vessel relationships between MIA and IAC diseases were compared using Pearsons chi-squared test.When there was an expected value 1 or a pretest probabilit

25、y close to the test level, Fishers exact test was used instead. Statistical results were considered significant when the P value was less than 0.05.Results Size variation of GGN lesionsThe average GGN size in the benign group, preinvasive group and adenocarcinomas group was 8.12.5 mm, 9.35.6 mm and

26、14.86.0 mm, respectively. No significant differences existed between the preinvasive group and the benign group (t = 0.64,p=0.53). However, there were significant differences between benign and preinvasive groups and the invasive adenocarcinoma group (t = 6.31,p=0.00; t = 3.98,p=0.00). Correlations

27、between GGN-vessel relationships and pathological findings Of 108 GGNs, type I, II, III and IV GGN vessell relationships were observed in 9, 58, 21 and 20 cases, respectively.the type II GGN-vessel relationship was the dominant relationship in each pathological group, seen in 9 benign (90.0 %), 16 p

28、reinvasive (66.7 %) and 33 invasive (44.6 %) GGN cases. compared with the low incidence of type III and IV relationships in benign and preinvasive groups the combined incidence of type III (25.7 %) and IV (25.7 %) relationships in the invasive adenocarcinoma group reached 51.3 %. MIA could present f

29、our types, with type II as the major type (48.7 %). The combination of type II and IV comprised about 80 % of the MIA subgroup; for IAC, type II and III had the same proportion of 40 %, hence the combination of 80 %. Statistical studies showed no difference in type II but a significant difference wa

30、s found in type III and IV between MIA and IAC lesions (p =0.02).The vessel(s) traveling through GGN could be artery(ies) (category A), vein(s) (category B), or artery(ies) and vein(s)(category C). There were no significant differences and correlations between vascular categories and GGN groups(p =0

31、.50 and 0.96, respectively) .A further examination of the correlation between vascular categories and GGNs with type III and IV relationships did not generate any significant results (p =0.70).Discussion Solitary pulmonary nodules (SPNs) are common findings in CT examinations and can be divided into

32、 two groups based on density variation: solid nodules and GGNs.In 2011, the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society proposed a new classification for lung adenocarcinomas.In the new classification system, the term bro

33、nchioloalveolar carcinoma (BAC) is no longer used. The former BAC concept applicable to multiple categories in the new classification system, such as AIS, MIA and the mucinous subtype of adenocarcinoma. Both AIS and AAH lesions are classified as preinvasive adenocarcinoma under the new classificatio

34、n system Early stage lung cancers often present as GGNs in CT images; thus, it is important to be familiar with the characteristics of GGNs with malignant potential, as timely surgical resection will improve patient survival and quality of life, and for patients with benign GGNs, unnecessary surgica

35、l procedures can be avoided.Clinical data have shown that nodule size is an independent predictive factor of malignancy, with size increasing the likelihood of malignancy increasing , consistent with our results that the mean sizes of GGNs in benign, preinvasive and adenocarcinoma groups were 8.1 mm

36、, 9.3 mm and 14.7 mm.Clinical experience has demonstrated that some common imaging features of malignant nodules, such as pleural indentation, spiculation and lobulation, are seldom seen in very early stage malignant GGNs. This demands further investigation of this particular abnormal imaging findin

37、g to minimise misdiagnosis. In the management of GGNs in our patients, clinical guidelines from the Fleischner Society and National Comprehensive Cancer Network (NCCN) were referenced .Each individual case was discussed by a multidisciplinary team, including diagnostic radiologists, thoracic surgeon

38、s and pathologists, to generate consequent management strategies.All patients received adequate follow-up observation with/without supportive or antiinflammatory treatment, which explained the fact that four GGNs disappeared prior to the next scheduled CT examination. Except for these four cases wit

39、hout biopsy, nodular lesions in the remaining 104 patients were surgically removed because of the continuous increase in size and/or mass on follow-up imaging studies. Considering the dramatically increasing incidence of lung cancer in China, patients and physicians are very alert to it and the trea

40、tment might be more aggressive than in Western countries.Tumour biology studies have revealed that vasculature remodelling or neoangiogenesis is one of the initiating events occurring in the early stage of tumour development. Therefore, analysis of GGNs and related blood supplying vessels could prov

41、ide information on GGN differentiation. Small blood vessels and the relationships between vessels and lesions can be readily revealed and evaluated in CT images acquired with modern multi-detector scanners, especially when imaging data are post-processed using advanced computer techniques, including

42、 MPR and CPR. Many studies have demonstrated that relationships between SPNs and vessels, especially the vascular convergence sign (VCS), are valuable for estimation of the malignancy potential of SPNsSome studies indicated that disease progression from AAH, AIS, MIA to IAC is a complicated, polygen

43、e-involved dynamic process. MIA or IAC may gradually develop from AAH and AIS . Interstitial fibre hyperplasia within lesions is the main contributing factor to type III and IV vascular morphological changes.the formation mechanism of VCS, leading to the conclusion that the course of adjacent vessel

44、s is subject to lesions, especially when diseases infiltrate the bronchiovascular bundle and interlobular septaAs a result , involved vessels might appear distorted, rigid or concentrated towards the lesion. Thus, it is reasonable to postulate假设 that the vascular convergence sign commonly seen in SP

45、Ns.Actually, the type IV GGN-vessel relationship resemblesVCS to some degree. The invasive adenocarcinoma group is composed of two subgroups, MIA and IAC. Subgroup analysis showed MIA and IAC had different patterns of GGN-vessel relationships.Type III vascular morphological changes were observed mor

46、e often in the IAC than MIA subgroup, indicating that with increasing malignancy, fibre hyperplasia stimulated by malignant tissues may become more severe, and subsequently impacts on vasculature become aggravated. Further more， tumour metabolism is faster than in normal tissues; therefore, the bloo

47、d supply demanded by tumours is much higher than in normal tissues.These mechanisms indirectly lead to vessel proliferation and irregular luminal dilation.Some studies have shown that endogenous and/or extrinsic tumor angiogenesis and neovascularisation could be the driving factors of vascular abnormalities observed in malignant early stage.As a CT imaging sign, VCS describes a relationship between