Value of multiplanar reconstruction Value of multiplanar reconstruction in MSCT in demonstrating thein MSCT in demonstrating the

relationship between solitary pulmorelationship between solitary pulmonary nodule and bronchusnary nodule and bronchus

Yun Cui, Da-qing Ma,Wei-hua LiuYun Cui, Da-qing Ma,Wei-hua Liu

Clinical Imaging 2009 Clinical Imaging 2009 ；； 33: 15–2133: 15–21

VocabularyVocabulary Nodule Nodule n. n. 1.1. 小瘤小瘤 ;; 小结 小结 2.(2.( 藻藻 )) 节节 ;(;( 菌菌 )) 瘤 瘤 3.3. 结核结核 Bronchus Bronchus n. n. 支气管支气管 Order Order 等级等级 ,, 阶层阶层 ; ; 顺序顺序 ,, 次序次序 Bronchi Bronchi 英英 ['brɑnkai]['brɑnkai] 美美 ['brɑnka ]ɪ['brɑnka ]ɪ (bronchus(bronchus 的复数的复数 )) 支气管支气管 bronchial bronchial 英英 ['br ki l]ɔŋ ə['br ki l]ɔŋ ə 美美 ['brɑ k l] a. ŋ ɪə['brɑ k l] a. ŋ ɪə 支气管的支气管的 Pneumonia Pneumonia 英英 [nju:'m unj ]ə ə[nju:'m unj ]ə ə 美美 [nju'monj ]ə[nju'monj ]ə abscess abscess 英英 ['æbsis]['æbsis] 美美 ['æbs s] n. ɪ['æbs s] n. ɪ 脓疮脓疮 Hemangioma Hemangioma 英英 [hi:,mænd i:' um ]ʒ ə ə[hi:,mænd i:' um ]ʒ ə ə 美美 [hi,mænd 'om ]ʒɪ ə[hi,mænd 'om ]ʒɪ ə n.n. 血管瘤血管瘤 Aspergilloma Aspergilloma 曲霉肿曲霉肿

LumenLumen n. n. 1. 1. 【物】流明【物】流明 2. 2. 【解】内腔【解】内腔 Obliterate Obliterate 英 英 [ 'blit reit]ə ə[ 'blit reit]ə ə 美 美 [ 'bl t ,ret] ə ɪ ə[ 'bl t ,ret] ə ɪ ə vt. 1. vt. 1. 擦掉擦掉 ...... 的痕迹的痕迹 ;; 冲刷；消灭 冲刷；消灭 2. 2. 忘掉忘掉 ,, 忘却忘却 dislocate dislocate 英 英 ['disl keit]ə['disl keit]ə 美 美 ['d sl ,ket]ɪ ə['d sl ,ket]ɪ ə vt. 1. vt. 1. 使移动位置使移动位置 ;; 使脱臼 使脱臼 2. 2. 弄乱弄乱 DilationDilation n. n. 扩张扩张 ;; 扩大部分扩大部分 Converge Converge 英 英 [k n'v :d ]ə ə ʒ[k n'v :d ]ə ə ʒ 美 美 [k n'v d ] ə ɝ ʒ[k n'v d ] ə ɝ ʒ vi. 1. vi. 1. 会合会合 ;; 趋于会合趋于会合 [(+on/toward)][(+on/toward)] 2. 2. 聚集聚集 ;; 趋于同样结果 趋于同样结果 [(+on)][(+on)] 3. 3. 【数】收敛【数】收敛 vt. 1. vt. 1. 使向一点会合使向一点会合 ;; 使聚集使聚集

sequestration sequestration 英英 [sikwe'strei n]ʃə[sikwe'strei n]ʃə 美美 [s kw 'stre n] ɪ ɛ ʃə[s kw 'stre n] ɪ ɛ ʃə n. 1. n. 1. 扣押扣押 ,, 没收没收 ,, 接收 接收 2. 2. 隔离隔离 Distomiasis Distomiasis 双盘吸虫病双盘吸虫病 notch notch 英 英 [n t ]ɔ ʃ[n t ]ɔ ʃ 美美 [nɑt ] ʃ[nɑt ] ʃ n. 1. n. 1. 刻痕刻痕 ;; 槽口槽口 ,, 凹口 凹口 2. 2. 等等 ,, 级 级 3.3. 峡谷峡谷 ,, 山峡山峡 Spinous Spinous 英 英 ['spain s]ə['spain s]ə 美 美 ['spa n s]a.ɪ ə['spa n s]a.ɪ ə 刺状的刺状的 Taper Taper 英 英 [‘teip ]ə[‘teip ]ə 美 美 [’tep ] n. ɚ[’tep ] n. ɚ

1. 1. 逐渐变得尖细 逐渐变得尖细 2. 2. 逐渐减少逐渐减少 ;; 逐渐变弱 逐渐变弱 3. 3. 锥形物锥形物 ;;尖塔尖塔 [C][C]

Bifurcation Bifurcation 英 英 [,baif :'kei n]ə ʃə[,baif :'kei n]ə ʃə 美 美 [,ba f 'ke n] ɪ ɚ ʃə[,ba f 'ke n] ɪ ɚ ʃən. n. 分叉分叉 ;; 分枝分枝 ;; 分歧分歧

Bifurcate Bifurcate 英 英 ['baif :keit]ə['baif :keit]ə 美 美 ['ba f ,ket] ɪ ɚ['ba f ,ket] ɪ ɚ vt. 1. vt. 1. 使分枝使分枝 ;; 使分叉 使分叉 vi. vi. 分枝分枝 ;; 分叉 分叉 a. a. 分叉的分叉的

IntroductionIntroduction

To our knowledge, At present, with the appliTo our knowledge, At present, with the application of thin-section scanning using multislcation of thin-section scanning using multislice spiral computed tomography (MSCT), the ice spiral computed tomography (MSCT), the lower-order bronchi can be observed clearly.lower-order bronchi can be observed clearly.

Furthermore, multiplanar recon-struction Furthermore, multiplanar recon-struction (MPR) of MSCT postprocessing enables the b(MPR) of MSCT postprocessing enables the bronchi that can not be shown on axial imageronchi that can not be shown on axial images to be demonstrated continuously and wholls to be demonstrated continuously and wholly from various angles and increases visualizy from various angles and increases visualization of the SPN–bronchus relation-ation of the SPN–bronchus relation-

ship (Fig.1).ship (Fig.1).

Fig.1Fig.1(A) Axial image showing a nodule in the left upper l(A) Axial image showing a nodule in the left upper lobe,but no nodule–bronchus relationship is visualiobe,but no nodule–bronchus relationship is visuali

zed.zed.(B) Same case. A bronchus leading to the nodule is s(B) Same case. A bronchus leading to the nodule is s

hown after the performance of MPR (arrow).hown after the performance of MPR (arrow).

The purpose of our study was to investThe purpose of our study was to investigate the value of MPR in MSCT in demigate the value of MPR in MSCT in demonstrating the SPN–bronchus relationsonstrating the SPN–bronchus relationship for differentiating malignant from hip for differentiating malignant from benign SPNs.benign SPNs.

Materials and methodsMaterials and methods

We collected 148 SPN cases confirmed by operWe collected 148 SPN cases confirmed by operation, bronchoscopy, drug treatment, and folloation, bronchoscopy, drug treatment, and follow-up between September 2006 and September w-up between September 2006 and September 2007.2007.

The patients (103 males and 45 females) rangeThe patients (103 males and 45 females) ranged in age from 18 to 80 years (average, 56 years).d in age from 18 to 80 years (average, 56 years).

The greatest diameter of the nodules, as measuThe greatest diameter of the nodules, as measured on CT scans, ranged from 1.1 to 4.0 cm (avred on CT scans, ranged from 1.1 to 4.0 cm (average, 2.6 cm).erage, 2.6 cm).

ResultsResults

3.1 Bronchi shown on axial and M3.1 Bronchi shown on axial and MPR imagesPR images

The SPN–bronchus relationship was positive iThe SPN–bronchus relationship was positive in 43 of 148 cases (29%) on axial images, and in n 43 of 148 cases (29%) on axial images, and in up to 95 cases (64%) on MPR images.up to 95 cases (64%) on MPR images.

It suggests that MPR can elevate the visualizatIt suggests that MPR can elevate the visualization of bronchi and can show the bronchial steion of bronchi and can show the bronchial stereo-structure continuously and wholly from vreo-structure continuously and wholly from various angles.arious angles.

The 95 cases included 62 malignant nodules aThe 95 cases included 62 malignant nodules and 33 benign nodules.nd 33 benign nodules.

Malignant nodules consisted of Malignant nodules consisted of adenocarcinoadenocarcinomama (AC; n=33), (AC; n=33), squamous carcinomasquamous carcinoma (SC; n=1 (SC; n=16), 6), bronchioal-veolar carcinomabronchioal-veolar carcinoma (BAC; n=3), (BAC; n=3), cacarcinosarcomarcinosarcoma (n=2), (n=2), adenosquamous carcinoadenosquamous carcinomama (AdCa; n=1), (AdCa; n=1), small-cell carcinomasmall-cell carcinoma (SCC;n= (SCC;n=1; Fig.2), and 1; Fig.2), and metastatic tumormetastatic tumor (MT; n=6). (MT; n=6).

Benign nodules consisted of Benign nodules consisted of tuberculomatuberculoma (n=1 (n=14), chronic 4), chronic pneumoniapneumonia (n=6), globular pneum (n=6), globular pneumonia (n=5), lung onia (n=5), lung abscessabscess (n=2), (n=2), sclerosing hemsclerosing hemangiomaangioma (n=2), inflammation (n=2), inflammation pseudonomapseudonoma (n= (n=1), 1), aspergillomaaspergilloma (n=1), pulmonary (n=1), pulmonary sequestratiosequestrationn (n=1), and pulmonary (n=1), and pulmonary distomiasisdistomiasis (n=1). (n=1).

With this CT protocol, the bronchi relaWith this CT protocol, the bronchi related to the nodules of the 95 cases were ted to the nodules of the 95 cases were mainly of fourth to sixth orders.mainly of fourth to sixth orders.

There was no significant difference beThere was no significant difference between malignant and benign nodules.tween malignant and benign nodules.

Fig.2Fig.2SCC in the right upper lobe.The bronchus is SCC in the right upper lobe.The bronchus is

obstructed by the tumor(arrow).obstructed by the tumor(arrow).

3.2 Nodule size and occurrence of 3.2 Nodule size and occurrence of the SPN–bronchus relationshipthe SPN–bronchus relationship

The results of our study showed that thThe results of our study showed that the bronchi were visualized in all nodulee bronchi were visualized in all nodules greater than 3 cm, in 87% of nodules s greater than 3 cm, in 87% of nodules less than 3 cm and greater than 2 cm, aless than 3 cm and greater than 2 cm, and in 37%of nodules less than 2 cm ( Tnd in 37%of nodules less than 2 cm ( Table 1).able 1).

It indicates that nodule size is a signifiIt indicates that nodule size is a significant factor for determining whether it cant factor for determining whether it has the bronchus sign or not.has the bronchus sign or not.

Fig.3 Fig.3 Tuberculoma in the right upper lobe. A broTuberculoma in the right upper lobe. A bro

nchus leading to the tuberculoma is seen (arnchus leading to the tuberculoma is seen (arrow).row).

Fig.4Fig.4Tuberculoma in the right upper lobe.The twTuberculoma in the right upper lobe.The twisted bronchus with a thickened wall (arrowisted bronchus with a thickened wall (arrow

s).s).

Fig.5Fig.5Moderately differentiated AC in the left loweModerately differentiated AC in the left lower lobe. At the site of the bronchus entering tr lobe. At the site of the bronchus entering the nodule, the tumor is associated with the he nodule, the tumor is associated with the

notch (arrow).notch (arrow).

Fig.6Fig.6Poorly differentiated AC in the left upper loPoorly differentiated AC in the left upper lobe.The bronchus is connected with the spinbe.The bronchus is connected with the spin

ous process of the tumor (arrow).ous process of the tumor (arrow).

3.3 Morphologic characteristics of 3.3 Morphologic characteristics of the SPN–bronchus relationshipthe SPN–bronchus relationship

We classified the SPN–bronchus relationship into four tWe classified the SPN–bronchus relationship into four typesypes

based on the classification made by Tsuboi and Choi etabased on the classification made by Tsuboi and Choi etal:l:

Type I (bronchus cut off at the edge of SPN), Type I (bronchus cut off at the edge of SPN), Type II (bronchus cut off in the SPN) (Table 2), Type II (bronchus cut off in the SPN) (Table 2), Type III (bronchus running through the whole SPN), Type III (bronchus running through the whole SPN), Type IV (bronchus running at the periphery of the SPN).Type IV (bronchus running at the periphery of the SPN). Each type was then classified into several subtypes.Each type was then classified into several subtypes. Many SPNs showed more than one type of SPN–bronchMany SPNs showed more than one type of SPN–bronch

us relationship.us relationship. No significant difference was observed between malignNo significant difference was observed between malign

ant and benign nodules in each type.ant and benign nodules in each type.

3.4 SPN–bronchus relationship an3.4 SPN–bronchus relationship and type of lung cancerd type of lung cancer

AC showed all four types of SPN–bronchus rAC showed all four types of SPN–bronchus relationship.elationship.

SC showed Type I,Type II,and Type IV patterSC showed Type I,Type II,and Type IV patterns,but no Type III pattern.ns,but no Type III pattern.

There was no significant difference between There was no significant difference between SC and AC in Type I, Type II,and Type IV patSC and AC in Type I, Type II,and Type IV patterns.terns.

Type III pattern was more common in AC buType III pattern was more common in AC but was not observed in SC ( P< .05).t was not observed in SC ( P< .05).

MT (n=6) most often had a Type I pattern (5 MT (n=6) most often had a Type I pattern (5 of 6) (Table 3).of 6) (Table 3).

3.5 SPN–bronchus relationship an3.5 SPN–bronchus relationship and degree of differentiation of lung d degree of differentiation of lung

cancercancer The degrees of differentiation of 38 AC and SC were The degrees of differentiation of 38 AC and SC were

confirmed (Table 4).confirmed (Table 4). We analyzed the appearance of the bronchus and foWe analyzed the appearance of the bronchus and fo

und that the bronchus'connection with the spinous und that the bronchus'connection with the spinous process of the SPN was more frequently seen in pooprocess of the SPN was more frequently seen in poorly differentiated lung cancer than in moderately dirly differentiated lung cancer than in moderately differentiated lung cancer, and that Type III pattern fferentiated lung cancer, and that Type III pattern was more common in moderately differentiated lunwas more common in moderately differentiated lung cancer than in poorly differentiated lung cancer ( g cancer than in poorly differentiated lung cancer ( P< .05).P< .05).

No statistical significance was shown between modNo statistical significance was shown between moderately and poorly differentiated lung cancers in oterately and poorly differentiated lung cancers in other patterns.her patterns.

In malignant SPN, tumor cells proliferate and invade In malignant SPN, tumor cells proliferate and invade the surrounding lung parenchyma continuously ( Fig.the surrounding lung parenchyma continuously ( Fig.7).7).

As a result, the adjacent bronchi are commonly obstrAs a result, the adjacent bronchi are commonly obstructed with tapered narrowing or flat ends ( Fig.8).ucted with tapered narrowing or flat ends ( Fig.8).

A bronchus obstructed abruptly can also occur in beA bronchus obstructed abruptly can also occur in benign SPNs, especially in tuberculoma, and there is ofnign SPNs, especially in tuberculoma, and there is often a capsule around the tuberculoma that can be coten a capsule around the tuberculoma that can be confluent with the bronchus.nfluent with the bronchus.

Different parts of a malignant nodule usually grow at Different parts of a malignant nodule usually grow at different speeds.different speeds.

Therefore, at the site of a bronchus entering the nodTherefore, at the site of a bronchus entering the nodule, the nodule can associate with the notch because ule, the nodule can associate with the notch because of a speed relatively slower growing than those in otof a speed relatively slower growing than those in other sites due to blockage by the bronchus. her sites due to blockage by the bronchus.

In addition, at the tumor–bronchus interface, thIn addition, at the tumor–bronchus interface, the nodule can also associate with the spinous proe nodule can also associate with the spinous process due to the tumor cells growing along with pcess due to the tumor cells growing along with peribronchial tissue and having a faster-growing eribronchial tissue and having a faster-growing speed.speed.

Besides, in benign SPN, especially in tuberculoBesides, in benign SPN, especially in tuberculoma, caseous content can be discharged through ma, caseous content can be discharged through the bronchus to thicken the bronchial wall, whicthe bronchus to thicken the bronchial wall, which may be associated with the bronchus being twih may be associated with the bronchus being twisted .sted .

Benign SPN cannot invade the parenchyma, so tBenign SPN cannot invade the parenchyma, so the bronchus in or around the nodules is usually he bronchus in or around the nodules is usually patent (Fig.9) or compressed,with an intact and patent (Fig.9) or compressed,with an intact and regular wall.regular wall.

However, in malignant SPN, the tumor However, in malignant SPN, the tumor cells always infiltrate the mucosa or sucells always infiltrate the mucosa or submucosa of the bronchus, resulting in bmucosa of the bronchus, resulting in a thickened wall and an irregularly nara thickened wall and an irregularly narrowed lumen (Figs.10–14).rowed lumen (Figs.10–14).

In lung cancer, there is often fibrous dIn lung cancer, there is often fibrous degeneration, resulting in the bronchial egeneration, resulting in the bronchial lumen being dilated and in the bronchlumen being dilated and in the bronchus converging with it (Fig.15).us converging with it (Fig.15).

Fig.8Fig.8Moderately differentiated AC in the left lobe.Moderately differentiated AC in the left lobe.The bronchus is cut off with a tapered narroThe bronchus is cut off with a tapered narro

wing after entering the tumor (arrow).wing after entering the tumor (arrow).

Fig.9Fig.9Inflammation pseudonoma in the right loweInflammation pseudonoma in the right lower lobe.The bronchus in the nodule runs natur lobe.The bronchus in the nodule runs naturally with a regular wall and lumen (arrow).rally with a regular wall and lumen (arrow).

Fig.10Fig.10Moderately differentiated AC in the right upModerately differentiated AC in the right upper lobe.The bronchi in the tumor run rigidlper lobe.The bronchi in the tumor run rigidl

y (arrow).y (arrow).

Fig.11Fig.11Moderately differentiated AC in the right loModerately differentiated AC in the right lower lobe.The bronchus in the tumor is irregwer lobe.The bronchus in the tumor is irreg

ularly narrowed (arrow)ularly narrowed (arrow)

Fig.12Fig.12Moderately differentiated AC in the right miModerately differentiated AC in the right middle lobe.The bronchial lumen beside the tuddle lobe.The bronchial lumen beside the tu

mor is irregularly narrowed (arrow)mor is irregularly narrowed (arrow)

Fig.14Fig.14Moderately differentiated SC in the left uppeModerately differentiated SC in the left upper lobe.The bronchus beside the tumor is invar lobe.The bronchus beside the tumor is inva

ded with an obliterated lumen (arrow).ded with an obliterated lumen (arrow).

Fig.15Fig.15Moderately differentiated AC in the right upModerately differentiated AC in the right upper lobe.The bronchi converging at the tumper lobe.The bronchi converging at the tum

or are seen (arrows).or are seen (arrows).

conclusionconclusion MPR can increase the demonstration oMPR can increase the demonstration o

f the SPN–bronchus relationship.f the SPN–bronchus relationship. The SPN–bronchus relation-ship is valThe SPN–bronchus relation-ship is val

uable in determining the nature and thuable in determining the nature and the degree of differentiation of SPN.e degree of differentiation of SPN.