INTERVENTIONAL

CHEST

RADIOLOGY

ABSTRACT .-Radiologically guided percutaneous drainage procedures are commonly performed to manage a variety of intrathoracic collections. As a natural extension of similar procedures performed for abdominal and pelvic collections, these procedures use both the conventional and cross-sectional imaging modalities to detect mtrathoracic collections and to guide safe percutaneous diagnostic aspiration and drainage. The high-resolution images obtainable on current computed tomographic and ultrasound units allow detection of lung abscesses, empyemas, malignant effusions, and infected mediastinal fhdd collections that are amenable to percutaneous drainage. Advances in catheter design and introduction techniques have allowed drainage of collections previously managed by open procedures. The ease of fluoroscopically guided catheter placement for treatment of spontaneous or biopsy-induced pneumothorax has provided a safe, effective, and comfortable alternative to blind large-bore surgical tube placement. Transthoracic needle biopsy of lung, mediastinal, and pleural or chest-wall masses has resulted from the availability of image intensifiers and cross-sectional imaging modalities useful in guidhrg needle placement and tissue sampling. Equally important has been the development of cytopathology as a subspecialty that can provide diagnoses of malignant and benign thoracic conditions from needle aspirates. This technique has had a major impact on the preoperative evaluation of the patient with a solitary pulmonary nodule and has eliminated unnecessary surgery in a significant percentage of such patients. Transcatheter arterial embolization has made a significant contribution to the management of the patient with massive hemoptysis and is the procedure of choice for treatment of pulmonary arteriovenous malformations. A thorough knowledge of the vascular anatomy of the thorax and expertise in catheterization and embolization techniques are prerequisites for the safe performance of these procedures.

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Jeflrey S. Klein, M.D., is an Assistant Professor of Radiology at the University of California School of Medicine in San Francisco, California, and head of thoracic imaging at the San Francisco General Hospital. His areas of research interest include interventional thoracic radiology and high-resolution computed tomography of the th0ra.x.

Scott Schultz, M.D., is currently a third-year resident in diagnostic radiology at the University of California Medical Center, San Francisco. He graduated magna cum laude from the University of Minnesota where he received a degree in ecology. He graduated from the Georgetown University School of Medicine in 1989 after junior election to Alpha Omega Alpha medical honor society. Cut-r Probl

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INTERVENTIONAL

PERCUTANEOUS INTRATHORACIC

CATHETER DRAINAGE FLUID COLLECTIONS

CHEST

OF

The treatment of intrathoracic fluid collections using imaging-guided percutaneous catheter drainage (PCD) has developed within the last 1.5 years. The ability of ultrasound and computed tomography (CT) to localize intrathoracic fluid collections accurately and advances in catheter design and interventional techniques have made PCD possible. Initially, referrals to the radiologist for PCD were limited to patients in whom pleural drainage with large-bore thoracostomy tubes had failed, or in whom open surgical drainage was either contraindicated or refused by the patient.” ’ More recently, PCD has been used as the initial therapy for empyemas3, 4 and malignant pleural effusions5, 6 and is being used more frequently for the treatment of mediastinal fluid collections7 and lung abscesses.8-10 The availability of radiologists skilled in interventional techniques, a high success rate and a low complication rate, and little or no patient discomfort from the small-diameter catheters used have led to widespread acceptance of the technique. INDICATIONS

The indications for percutaneous aspiration and drainage of intrathoracic fluid collections are as follows: 1. Loculated or free-flowing empyema or complicated parapneumonic effusion 2. Drainage and sclerosis of malignant pleural effusion

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RADIOLOGY

3. Lung abscess in a patient in whom conservative management failed 4. Management of large, recurrent serous effusion (e.g., resulting from ascites) 5. Drainage of chylothorax or hemothorax 6. Diagnosis and treatment of bronchogenic cyst

CONTR4lNDICATIONS

There are no absolute contraindications to PCD. A patient who cannot safely be placed prone or decubitus to access the collection may require general anesthesia for performance of the procedure. Underlying coagulopathy (prothrombin time >5 seconds over control) or thrombocytopenia (platelet count 1500 ml), chronic, noninfected fluid collections should be drained more slowly, generally during 24 to 48 hours, to avoid the development of reexpansion pulmonary edema. The catheter is attached to a Pleur-evac device (Deknatel Co., Fall River, MA), and suction pressure of -20 cm H,O suction applied. All connections are secured with tape. Immediately after catheter placement for drainage of infected collections, CT or ultrasound examination is repeated so that improperly placed catheters can be repositioned or additional catheters placed to drain any residual collections.

SPECIFIC COLLECTIONS Empyema Empyema literally means pus in the pleural space. Although pneumonia is the most common predisposing factor, empyema may develop as a postoperative complication, as a result of blunt OI penetrating chest trauma or esophageal rupture, or without any identifiable cause. The mechanism of pleural fluid formation associated with pneumonia involves an increase in the permeability of the capillary network beneath the visceral pleura that occurs when the parenchymal inflammatory process reaches the pleural surface. This leads to an accumulation of fluid with a protein concentration of >3.0 gm/dl (or pleural fluid protein/serum protein ratio >0.5), which is termed an exudative effusion. Processes that do not directly affect the pleura but alter the hydrostatic or oncotic pressures governing normal pleural fluid movement from the parietal to visceral pleural capillaries, such as congestive heart failure, renal failure, and hypoalbuminemia, lead to effusions with a protein concentration of 1500 ml) chronic pleural-fluid collection may lead to reexpansion pulmonary edemasY; these collections should be drained gradually over a 24to 48-hour period. PERCUTANEOUS CATHETER OF PNEUMOTHORAX

DRAINAGE

Since the technique of rapid drainage of pneumothorax in the radiology department was first described by Sargent and Turner in 1970,“” smallbore catheters have been used by radiologists to treat pneumothoraces complicating transthoracic needle biopsy and other percutaneous transthoracic procedures.5Y-64 The ease and accuracy of placement, proved effectiveness, and patient comfort of radiologically guided pneumothorax drainage with small catheters has made this the technique of choice for treatment of pneumothorax resulting from biopsy (percutaneous or transbron-

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chial), thoracentesis, central spontaneous p~~eurnotl~omx.

line

placement,

or

INDICATIONS

The indications for radiologically guided catheter drainage of pneumothorax are as follows: 1. Pneumothorax >20% 2. Pneumothorax 48 hours, air should be evacuated slowly during 6 to I2 hours to prevent reexpansion pulmonary edema. Sterile technique to avoid infection is strictly adhered to in all but the most unstable patients who require emergent catheter placement for pneumothorax drainage. MISCELLANEOUS THORACIC DRAINAGE PROCEDURES DRAINAGE

OF BRONCHOGENZC

CYSTS

Successful transthoracic drainage of subcarinal bronchogenic cysts has recently been described. Using a posterior paraspinal approach with the patient prone, Adam et al.67 were able to puncture and drain a symptomatic subcarinal cyst by incremental advancement of a 21-gauge needle and injection of 5 ml aliquots of saline solution to expand the extrapleural space and avoid pleural transgression. A 6F catheter was then placed and 160 ml mucoid material drained with symptomatic and spirometric improvement. Recently, Adam et al.6x reported on the use of an extrapleural technique and approach for the biopsy or drainage of six mediastinal lesions in five patients. TZUNSCATHETER OF ASPERGZUOIWI

TREATMENT

Aspergillomas form in preexisting pulmonary cavities, cysts, or bullae and are associated with 240

massive, life-threatening hemoptysis. Surgical resection remains the treatment of choice but is limited to those with adequate pulmonary reserve and technically resectable lesions. Several methods of nonsurgical treatment for aspergillomas have been described, including intravenous administration of amphotericin, endobronchial drainage, and percutaneous transcatheter intracavitary administration of amphotericin and aspergilloma evacuation.“” We have recently used this latter technique successfully in a 32-year-old patient with sarcoidosis and upper-lobe cystic disease who had massive hemoptysis from a recurrent left-upper-lung aspergilloma 3 years after leftupper-lobectomy for aspergilloma. CT and fluoroscopic placement of a drainage catheter was achieved and a 14day course of intracavitary amphotericin and cavitary lavage allowed transcatheter removal of the aspergilloma without recurrence of aspergilloma formation or hemoptysis over an b-month follow-up period (Fig 12).

TRANSTHORACLC

NEEDLE

BIOPSY

First described in 1883 and popularized in the 1960s by Dahlgren and Nordenstrom, transthoracic needle biopsy (TNB) is a diagnostic procedure performed by radiologists and pulmonologists to evaluate focal chest disease. Advances in imaging technology and interventional techniques, the development of small-gauge needles capable of providing histologic specimens, and the emergence of cytopathology as a subspecialty have made TNB a safe, rapid, and accurate diagnostic test.

INDICATIONS

AND

SELECTION

OF PATIENTS

Most patients referred for TNB have been evaluated by a primary-care physician, pulmonologist, or thoracic surgeon and fall into one of the following categories: 1. A patient with a new or enlarging solitary pulmonary nodule or mass 2. A patient with an undiagnosed mediastinal mass 3. A patient with a hilar mass in whom bronchoscopy is negative for an endobronchial component 4. A patient with an intrathoracic or extrathoracic malignancy and a hilar, mediastinal, needing or parenchymal mass or adenopathy staging 5. A patient with focal or multifocal parenchyCurr

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FIG 12. Percutaneous transcatheter removal of aspergilloma. A, CT scan at level of aortic arch shows marked mediastinal lymph node enlargement from sarcordosis and a lobulated mass (arrows) in a left upper lung bulla representing an aspergilloma. B and C, axial image and coronal reconstruction show catheter surrounding the aspergilloma within the bulla. D and E, axial and coronal images after 14 days of intracavitary amphotericin show resolutron of the aspergilloma.

mal consolidation or abscess in whom an infectious organism has not been isolated ti. Selected patients with suspected lymphan@tic carcinomatosis or opportunistic pneumonia It is important to realize that the indications for transthoracic needle biopsy of an undiagnosed solitary pulmonary nodule vary between institutions. The decision to perform TNB in any individual depends on many factors. These include the radiographic characteristics of the lesion, patient age, smoking and occupational history, the pretest probability of lung cancer (i.e., the overall prevalence of granulomatous disease and lung cancer in the local population), the experience of the physician performing the biopsy, the availability of rapid CT to guide biopsy of certain lesions, the likelihood of serious complications from TNB and the patient’s ability to tolerate such complications, the availability and expertise of cytopathologists, and the wishes of the patient, referring physician, and thoracic surgeon. Although some physicians will perform TNB in virtually any patient with an undiagnosed pulmonary lesion, despite the low likelihood of avoiding thoracotomy,70 others suggest a more selective approach.7’ The latter include Berger et aL7” who, after noting the development of pleural malignancy after TNB in two patients with squamous-cell carcinoma, argued that operable lesions in patients undergoing TNB may carry a worse prognosis than in those in whom surgery Curr

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is performed without preoperative TNB.7Z Despite this and similar sporadic observations, extensive experience with TNB over the past two decades confirms its safety. However, the decision to perform this procedure should be made on an individual basis after consultation with the responsible clinicians and the patient. TNB should be performed by physicians who have extensive experience with this technique, and access to the imaging modalities required to perform the procedure. Equally important is the ability of the operator to manage TNB-related complications quickly and effectively. The availability of expert cytopathologists is critical to the proper handling and interpretation of aspirated cytologic specimens. A close rapport between operator and radiology technician facilitates accurate localization of the lesion and shortens the duration of the procedure.

CONTRAINDICATIONS

There are no absolute contraindications to TNB of the chest. However, several preexisting conditions significantly increase the complication rate from TNB or render any complication more significant, such as a pneumothorax in a patient with a contralateral pneumonectomy. When one or several of these factors are present, an attempt is made at correcting them, or alternative methods of 241

diagnosis are considered. These relative contraindications are listed below: 1. Moderate or severe obstructive lung disease (forced expiratory volume in 1 second IFEV,I Cl.0 L) 2. Use of positive end-expiratory pressure ventilation 3. Bullae in the vicinity of the lesion to undergo biopsy 4. Bleeding diathesis (prothrombin time >3 seconds over control or platelet count 50% recovery of histologic specimens with the use of 22-gauge cutting needles, this has not been our experience. When it is necessary to obtain a specimen for histologic evaluation, we use a larger cutting needle alone or in tandem with a thinner needle, place a al-gauge automated cutting needle through the outer coaxial needle, or obtain a tissue specimen on withdrawal of the outer coaxial needle. When the lesion to undergo biopsy provides a large window (usually large mediastinal, pleural, or chest wall masses), a cutting needle can be safely used initially and provides the best specimen (Fig 19).85,104 Similarly, when expert cytopathologists are not available, it is preferable to attempt a core biopsy for histologic diagnosis.105 When TNB is performed to isolate the causative organisms in pneumonia or lung abscess, a 22-gauge Chiba needle (Cook1 usually provides an adequate specimen. TECHNIQUE

needles used for TNB. (From Klein JS, In Comof the Body. Philadelphia. WB Saunders, 1992,

The gowned patient is brought to the site where the biopsy will be performed, and a peripheral inCur-r I’rubl

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FIG 19. Cutting-needle biopsy of pleural metastases from nasopharyngeal effusion. B, CT scan durrng biopsy of a lobulated pleural mass with imen confirmed metastatic disease

travenous line is started. An automatic blood pressure cuff is placed on the arm opposite the intravenous line, and chest leads are attached to allow constant electrocardiographic monitoring during the procedure. The patient is placed either supine, prone, or, uncommonly, in the decubitus position, depending on the approach used. The patient’s arms are raised above the head if possible. Generally, the shortest path that affords a reasonable window to the lesion is chosen and avoids traversing bullae or vessels. As discussed above, prebiopsy CT provides valuable information in choosing the appropriate needle pathway. The skin entry site is identified with fluoroscopy, CT, or ultrasound and marked with indelible ink. Care must be taken to choose an entry site that allows safe introduction of the biopsy needle(s) over the upper portion of the adjacent rib. For lesions that lie directly beneath a rib or the sternum, a transosseous approach using a 20-gauge Westcott needle screwed through the overlying bone and into the lesion for sampling has been described.‘06 After washing this area with povidone-iodine solution, a liberal amount of 1% solution of lidocaine is injected intradermally and into the superficial and deep subcutaneous tissues. It is important to anesthetize the heavily innervated parietal pleura adequately. A small stab incision is made to ease introduction of the needle. In patients undergoing TNB for possible malignancy, we usually use a coaxial technique (Fig 20). The patient is instructed to suspend respiration at functional residual capacity while an M- or 1% gauge needle is placed through the incision to a Curr

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carcinoma. A, posteroanterior ASAP automated core biopsy

radiograph shows a large left pleural needle. Histologic examination of spec-

predetermined depth or until resistance is felt. The needle should be positioned with its tip immediately adjacent to the proximal edge of the lesion. The position of the tip of the needle is checked by fluoroscopy of the chest in a plane perpendicular to the axis of the needle, by obtaining CT scans at and just above and below the level of skin entry, or with real-time ultrasound. If the needle is not properly positioned, it is adjusted by partial withdrawal and reangulation until the tip is just proximal to the lesion. When a biopsy is being performed under CT guidance, repeated images are obtained to confirm proper needle position. In patients with small central lesions adjacent to vital cardiovascular structures, a modified coaxial technique may be used to safely place the larger needle adjacent to the lesion without risking injury to adjacent cardiovascular structures.1’17,‘08 With this method, a 23-gauge needle with removable hub is placed to the lesion under CT guidance. The hub of the needle is then removed, and a Is-gauge needle is placed over the 2%gauge needle to the edge of the lesion. Removal of the 23-gauge needle now allows placement of 22-gauge aspiration needles for multiple biopsies. Once properly positioned, the patient is again instructed to hold his or her breath, and the stylet of the guiding needle is removed. A 22-gauge Greene, Chiba, or Westcott needle is placed through the outer needle and into the lesion. The operator can feel the increased resistance as the fine needle pierces the lesion. Immediately after the stylet is removed, a lo- or 20-ml syringe with a slip-tip is attached to the thin needle, and a tissue 249

u I--

22-gauge

nh-

19.5-gauge

ChibalWestcott

Per-cu-cut

FIG 20. Coaxial

technique

for TNB.

sample is obtained by creating suction and piercing the lesion repeatedly with a series of up-anddown and rotatory motions. The biopsy can be visualized under fluoroscopy or ultrasound to assure that the needle is traversing the lesion and :i,,not simply displacing it. Suction is then disc ued and the biopsy needle removed, wit], taken to occlude the lumen of the outer Iimmediately on removal of the thin needle. lt is important to stop suction before blood appears in the needle hub, inasmuch as clotting may prevent a diagnostic smear from being obtained or preclude culture of the aspirated material. The stylet for the outer needle is then replaced into the needle while the patient suspends respiration, until the next fine needle pass or removal of the outer needle. In patients with pneumonia or abscess, a 22-gauge Chiba needle is placed with its tip in the consolidated region or abscess cavity, respectively. For pneumonia, a 20-ml syringe containing 3 to 5 ml of nonbacteriostatic saline solution is attached, the saline solution injected, and continuous suction applied until fluid is aspirated into the syringe. The syringe and attached needle are carefully handed to the cytopathologist, who then ejects the 250

aspirated material onto prepared slides. Any visible tissue fragments are isolated and placed in formalin. The aspirate is smeared onto the slides and is immediately fixed in alcohol. The slides are stained with toluidine blue and examined under a portable microscope. When a spring-activated needle is used, the inner stylet is advanced from within the cutting cannula, and the tissue within the slotted receptacle is teased off and into formalin. When microbiologic stains and cultures are required, the needle-syringe combination is covered with a protective sterile plastic sheath and transported immediately to the laboratory for the appropriate stains and cultures. When aspiration of a cystic lesion yields several milliliters of fluid, this should be expelled into a sterile test tube for cell block and culture. The decision to perform additional biopsies depends on whether the cytopathologist is confident in making a diagnosis with the available material. If after several aspirations the cytopathologist is unable to make a diagnosis of malignancy, and the operator can document accurate placement of the biopsy needle within the lesion, we may attempt a core biopsy. The use of an outer coaxial needle with a circumferential cutting tip allows for sampling of core tissue on removal. Recently we have used a al-gauge automated cutting needle (ASAP core biopsy needle, Medi-tech) that can be placed coaxially through an I&gauge cannula for obtaining core biopsy specimens. In cases where malignancy has not been confirmed, additional aspirates are sent to the microbiology department for appropriate fungal and mycobacterial stains and cultures. If malignancy is confirmed, the outer needle is withdrawn during suspended respiration. We do not routinely use a blood patch on withdrawal of the outer needle.

IMMEDIATE

POSTPROCEDURAL

CARE

After completion of the biopsy, fluoroscopy is used to check for the presence of a pneumothorax. If the biopsy is performed under CT guidance, a single expiratory scan is obtained through the lower thorax. A large or symptomatic pneumothorax should be treated by percutaneous placement of an SF or 9F catheter. The patient is then moved onto a gurney and carefully positioned with the biopsy site down, usually prone or supine. Dependent positioning may reduce the incidence of postbiopsy pneumothoraxlOs-l’l and prevent the potential transbronchial spread of biopsy-induced intraparenchymal hemorrhage. Immediately after Curr

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a biopsy performed with fluoroscopy or ultrasound, an upright expiratory chest film is obtained. This film is compared with the prebiopsy films to exclude a pneumothorax or intraparenchymal or intrapleural hemorrhage. Stable inpatients may be transferred to the ward for further observation. Outpatients are brought by gurney to the radiology recovery room. All patients remain in the biopsy-side down position for 3 hours. A nurse monitors the patient’s vital signs, breath sounds, and oxygen saturation by pulse oximetry every 15 minutes for the first hour and every 30 minutes thereafter. The patient is queried for complaints of chest pain or shortness of breath. If the suspicion of a new or enlarging pneumothorax arises, a chest film is obtained immediately. Otherwise, a repeated upright expiratory film is obtained 3 hours after the biopsy. If there is either no pneumothorax or a small stable pneumothorax in an asymptomatic patient, the patient may be safely discharged home. This policy is based on the results of a retrospective review of 673 TNBs of the thorax by Perlmutt et al.,ll” who found that 98% of all pneumothoraces and 100% of pneumothoraces requiring intervention (i.e., chest-tube drainage) were detected within 1 hour of the biopsy. The patient is asked to avoid both straining and all but mild physical exertion until the following morning and is instructed to proceed immediately to an emergency department should any pleuritic chest pain, hemoptysis, or shortness of breath develop. COMPLICATIONS

AND

THEIR

TREATMENT

The most common complications from TNB are pneumothorax and hemoptysis. The reported incidence of pneumothorax ranges from 0% 75,g4J‘13 to 61%,114 with most large series reporting an incidence of 5% to 30%.* Perhaps more important than the overall pneumothorax rate is the percentage of biopsy patients requiring treatment of pneumothorax with chest-tube drainage, which is generally reported as 0% to 15% .t Factors reportedly associated with a higher incidence of pneumothorax include advanced patient the presence of obstructive airway age, disease,“l PI’3 arterial hypoxemia,‘“3 intractable coughing, increased depth of the lesion,lz4 decreased size of the lesion, increased outer diameter of biopsy needle, the use of cutting needles or biopsy gunslz5 for core biopsies versus smaller aspirating needles for cytologic examination, in-

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*References

74,83,84,86,

tReferences

71, 78,81,

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95,101,103,105,115-120 83, 84,103,

November/December

109, 115, 117. 1992

creased number of times the pleura is traversed, increased duration of the procedure, cavitary lesions, and positive pressure ventilation. Inexperience of the person performing the biopsy, unavailability of a cytopathologist on site for a rapid interpretation,‘“” and CT-guided biopsies are also associated with a higher incidence of pneumothorax. It is likely that these latter three risk factors for TNBinduced pneumothorax are related to an increased duration of the procedure and requisite increased number of pleural punctures in these situations. The recognition of factors associated with a higher rate of TNB-induced pneumothorax is important in that it allows for the prebiopsy categorization of patients as to risk of subsequent pneumothorax. Recognizing risk factors may lead to attempts to correct or improve some of these factors (e.g., the administration of bronchodilators or antitussives, avoidance of bullae by use of CT guidance) or to seek alternative initial methods of diagnosis, such as bronchoscopy with brushing, lavage, and biopsy. Furthermore, this may prompt a prebiopsy assessment of lung volumes and spirometry. In this vein, Quon et al.lZ3 in a retrospective study of 308 chest biopsies, each consisting of an average of three passes with a Z&gauge needle, found that severe airway obstruction (FEV,/forced vital capacity