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E8. Bronchoscopic biopsy of isolated, peripheral lung lesions underendobronchial ultrasound (EBUS) and electromagnetic guidance
E8. Bronchoscopic biopsy of isolated, peripheral lung lesions under endobronchial ultrasound (EBUS) and electromagnetic guidance Helnnch
D. B e c k e r
Thoraxklmlk at Heidelberg University School of Medicine, Heidelberg, Germanv
Background: Ltmg cancer IS a leading cause of death More than 15qU""~ solitary pulmonary nodules are reported annuallv in the US The poportlon of peripheral nodules is increasing The presence of peripheral lesions frequently leads to biopsy and diagnostic tests Unfortunately, conventional bronchoscopy under fluoroscopic guidance is unreliable m obtaining biopsies from lesions m the periphery of the lung, especially ff those lesions are less than 2 cm in diameter and w h e n thev are hidden behind the heart, infiltrates, or pleural effusion Bronchoscopy under CT fluoroscopic guidance produced a 7qO,, success However, the drawbacks are considerable radiation exposure to patient and staff and the necessltv of finding CT time for the procedure I f a biopsy is not obtained, more lnVaslve methods, such as transthoraclc needle biopsy, wldeoasslsted thoracoscopy, or diagnostic thoracotomv can be used, but thev have a greater risk of complications In addition almost h a l f of the resected lesions are benign, and in screening programs, this proportion m a v be a b o ~ 9qO,, Thus the increased risk of complications from more mvaslve techniques must be weighed against the probability of finding benign lesions This is whv new technologies for diagnosing those lesions are desirable Endobronchial Ultrasound (EBUS): For this purpose we investigated the application of miniaturized ultrasonic transducers (C)l.vmpus Co, Tokyo, Japan) that were constructed for exploration of the central alrwavs W h e n thev are inserted into the periphery of the lung, a typical irregular snowstorm hke image is obtained. In contrast, w h e n a peripheral solid lesion is reached it can be differentiated from the surrounding lung tissue bv its darker internal echo structure Thus bv directing peripheral biopsies w i t h the help of E B U S we could improve results to 7qO,, as compared to current approximately 5qO,, bv fluoroscopic guidance Especially m lesions smaller than 3 cm EBUS was significantly superior This has been confirmed bv other investigators W h e n the probe is inserted v i a a catheter that is left m place as extended working channel, results of biopsies can be further improved B v analyzing the distributions of grey scale signals within the lesion even the nature, whether benign or malignant, can be accuratelv predicted in over 9qO,, Thus E B U S has become a valuable tool m directing bronchoscoplc diagnostic procedures for diagnosing peripheral lesions of the lung However, ultrasound technolog2v is demanding, and the ultrasound probes can not be a c t l ~ l v steered bevond
the visible parts of the alrwavs Given these limitations, an advanced technology ldeallv 1) would provide realtime Imaging that is independent of fluoroscopic visibility: 2) would be able to track the location of the biopsy probe as it approaches the peripheral lesion: and 3) would allow the biopsy probe to be navigated within the periphery of the lung, A new, electromagnetic guidance svstem using virtual bronchoscopy and three-dimensional (3D) CT images, m combination w i t h a steerable probe appears to meet these three ideal criteria
The Electromagnetic Navigation System (SuperDimension Bronchial System / SDBS): l A n ~l~ctromagn~ttc board is positioned under the upper end of the bronchoscopy table and creates a week magnetic field around the patient's chest 2 A retractable s~nsor prob~ (locatable guide, LG I, 1 m m m diameter and 8 m m long, on the tip of a flexible metal cable is the m a r e feature of the svstem Inside the electromagnetic field, its position, as well as motion can be displayed on a monitor m real time and superimposed on previously acquired CT Imams A n added feature is the 30~" steerabllltv of its tip provided bv 4 wires controlled bv a rotating -knob and a lever on the proximal handle A socket at the handle provides the electronic connection to the computer 3 The retractable sensor probe is inserted through afl~ r~b/e catlz~t~r, 13q~cm long and 1 9 m m in diameter, that serves as an extended working channel (EWC) 4 The computer software allows the bronchoscoplst to observe a graphic depiction of the sensor probe's position and pre-reglstered anatomical landmarks that are superimposed on the reconstructed 3-D CT images of the patient's anatomv A n additional feature is the '~tlp-vlew", which gives information on where to turn the rotating -knob on the handle to guide the probe to the targeted lesion After successful animal experiments and preliminary clinical results we investigated the svstem in two prospective studies In the first studv applicability and safetv where the goals Using the SDBS m 3q~ patients we could obtain a definite diagnosis in 69°,, without major side effects The second studv concerned the accuracv of the SDBS as compared to Imaging bv the flexible endoscope Deviation was 2 4 m m on average and was considered close enough to gain approval of the svstem bv the F D A The time we needed
was approximately 3 m m for planning, 2 m m for registration with the SDBS during bronchoscopy, and navigation to the target added 7 r a m Conclusion: E B U S and electromagnetic navigation in our experience are safe procedures and help improving the results of bronchoscoplc biopsies in peripheral lesions of the lung; On the basis of our experience, the SDBS svstem
has alreadv been improved, and further refinements are on the wav such as leaving an electronic track towards the lesion during planning We expect that the SDBS navigation svstem and EBUS w i l l be valuable tools in bronchoscoplc diagnosis of peripheral lesions of the lung and that thev m a v also support the treatment of these lesions through the endobronchlal route
D. B e c k e r
Thoraxklmlk at Heidelberg University School of Medicine, Heidelberg, Germanv
Background: Ltmg cancer IS a leading cause of death More than 15qU""~ solitary pulmonary nodules are reported annuallv in the US The poportlon of peripheral nodules is increasing The presence of peripheral lesions frequently leads to biopsy and diagnostic tests Unfortunately, conventional bronchoscopy under fluoroscopic guidance is unreliable m obtaining biopsies from lesions m the periphery of the lung, especially ff those lesions are less than 2 cm in diameter and w h e n thev are hidden behind the heart, infiltrates, or pleural effusion Bronchoscopy under CT fluoroscopic guidance produced a 7qO,, success However, the drawbacks are considerable radiation exposure to patient and staff and the necessltv of finding CT time for the procedure I f a biopsy is not obtained, more lnVaslve methods, such as transthoraclc needle biopsy, wldeoasslsted thoracoscopy, or diagnostic thoracotomv can be used, but thev have a greater risk of complications In addition almost h a l f of the resected lesions are benign, and in screening programs, this proportion m a v be a b o ~ 9qO,, Thus the increased risk of complications from more mvaslve techniques must be weighed against the probability of finding benign lesions This is whv new technologies for diagnosing those lesions are desirable Endobronchial Ultrasound (EBUS): For this purpose we investigated the application of miniaturized ultrasonic transducers (C)l.vmpus Co, Tokyo, Japan) that were constructed for exploration of the central alrwavs W h e n thev are inserted into the periphery of the lung, a typical irregular snowstorm hke image is obtained. In contrast, w h e n a peripheral solid lesion is reached it can be differentiated from the surrounding lung tissue bv its darker internal echo structure Thus bv directing peripheral biopsies w i t h the help of E B U S we could improve results to 7qO,, as compared to current approximately 5qO,, bv fluoroscopic guidance Especially m lesions smaller than 3 cm EBUS was significantly superior This has been confirmed bv other investigators W h e n the probe is inserted v i a a catheter that is left m place as extended working channel, results of biopsies can be further improved B v analyzing the distributions of grey scale signals within the lesion even the nature, whether benign or malignant, can be accuratelv predicted in over 9qO,, Thus E B U S has become a valuable tool m directing bronchoscoplc diagnostic procedures for diagnosing peripheral lesions of the lung However, ultrasound technolog2v is demanding, and the ultrasound probes can not be a c t l ~ l v steered bevond
the visible parts of the alrwavs Given these limitations, an advanced technology ldeallv 1) would provide realtime Imaging that is independent of fluoroscopic visibility: 2) would be able to track the location of the biopsy probe as it approaches the peripheral lesion: and 3) would allow the biopsy probe to be navigated within the periphery of the lung, A new, electromagnetic guidance svstem using virtual bronchoscopy and three-dimensional (3D) CT images, m combination w i t h a steerable probe appears to meet these three ideal criteria
The Electromagnetic Navigation System (SuperDimension Bronchial System / SDBS): l A n ~l~ctromagn~ttc board is positioned under the upper end of the bronchoscopy table and creates a week magnetic field around the patient's chest 2 A retractable s~nsor prob~ (locatable guide, LG I, 1 m m m diameter and 8 m m long, on the tip of a flexible metal cable is the m a r e feature of the svstem Inside the electromagnetic field, its position, as well as motion can be displayed on a monitor m real time and superimposed on previously acquired CT Imams A n added feature is the 30~" steerabllltv of its tip provided bv 4 wires controlled bv a rotating -knob and a lever on the proximal handle A socket at the handle provides the electronic connection to the computer 3 The retractable sensor probe is inserted through afl~ r~b/e catlz~t~r, 13q~cm long and 1 9 m m in diameter, that serves as an extended working channel (EWC) 4 The computer software allows the bronchoscoplst to observe a graphic depiction of the sensor probe's position and pre-reglstered anatomical landmarks that are superimposed on the reconstructed 3-D CT images of the patient's anatomv A n additional feature is the '~tlp-vlew", which gives information on where to turn the rotating -knob on the handle to guide the probe to the targeted lesion After successful animal experiments and preliminary clinical results we investigated the svstem in two prospective studies In the first studv applicability and safetv where the goals Using the SDBS m 3q~ patients we could obtain a definite diagnosis in 69°,, without major side effects The second studv concerned the accuracv of the SDBS as compared to Imaging bv the flexible endoscope Deviation was 2 4 m m on average and was considered close enough to gain approval of the svstem bv the F D A The time we needed
was approximately 3 m m for planning, 2 m m for registration with the SDBS during bronchoscopy, and navigation to the target added 7 r a m Conclusion: E B U S and electromagnetic navigation in our experience are safe procedures and help improving the results of bronchoscoplc biopsies in peripheral lesions of the lung; On the basis of our experience, the SDBS svstem
has alreadv been improved, and further refinements are on the wav such as leaving an electronic track towards the lesion during planning We expect that the SDBS navigation svstem and EBUS w i l l be valuable tools in bronchoscoplc diagnosis of peripheral lesions of the lung and that thev m a v also support the treatment of these lesions through the endobronchlal route