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INTRODUCTION

Pleural disease is a common problem worldwidewith an estimated incidence of pleural effusion of1 million cases per year in the USA (1). The re-commended sequence of investigations in pleuraleffusion includes history, clinical examination,chest radiography and pleural aspiration (2). Un-fortunately, these investigations may not allow fora confident diagnosis of the cause of pleural effu-sion in all cases. In the case of an undiagnosedexudative effusion with pleural thickening, pleuralbiopsy may be necessary for diagnosis. Biopsy canbe performed as a blind biopsy with an Abram’sor Cope needle; under direct visualisation withmedical thoracoscopy or video-assisted thoracos-copic surgery (VATS); as an open surgical biopsyor under image guidance. Image-guided biopsy isa technique with high sensitivity and specificitywhich can be performed as a day case procedureunder local anaesthesia. A randomised trial hasshown that it is more accurate than blind biopsy(3). The main alternative is medaical thoracos-copy, which allows direct visualisation of the pleu-ra, drain insertion and pleurodesis but requires se-

dation or general anaesthesia. In a small but sig-nificant proportion of patients, it may not be pos-sible to enter the pleural space, either due to ribcrowding or a small or multi-septated effusion.

INDICATIONS

1. Suspected Malignant Pleural Effusion

Studies have demonstrated that approximately60% of malignant pleural effusions can be diag-nosed by aspiration and cytological examinationalone (4-7). This drops to approximately 30% inmesothelioma. A second diagnostic aspirate is oflimited benefit and a third aspirate is rarely help-ful (7) and, as such, image-guided biopsy may beneeded for diagnosis. CT guided biopsy has a re-ported sensitivity of 76-88% and specificity of upto 100% for diagnosis of malignant pleural thicke-ning including a sensitivity of 83-86% and speci-ficity of up to 100 % for diagnosis of mesothelio-ma (8-11).

2. Undiagnosed Pleural Thickening in theAbsence of an Effusion

Pleural thickening may be present in the absenceof pleural fluid. This may be benign or malignant.

CT Guided Pleural Biopsy

EJ Helm, FV Gleeson11,,22

Department of Radiology1 and University of Oxford2, Churchill Hospital, Old Road, Headington, Oxford. OX3 7LJ

Plevral Yöntem

Benign causes include benign asbestos relatedpleural thickening, rheumatoid arthritis, tubercu-losis and previous pleural infection (empyema) orhaemothorax. The clinical history may be helpfulin determining the cause but, where there is diag-nostic doubt, image guided pleural biopsy can behelpful. Image guided biopsy is as effective in theabsence of an effusion as reported in section 1.

3. Pleural Masses

Pleural masses may be seen without an associatedeffusion. Pleural masses may be benign or malig-nant, discrete or multiple. Malignant pleural mas-ses may be due to primary pleural malignancy(mesothelioma) or metastatic disease, commonlyfrom breast cancer, lung cancer or thymoma. Be-nign pleural masses include pleural fibroma altho-ugh this does not usually require biopsy since itscharacteristic CT appearance usually allows a con-fident diagnosis.

Contraindications

There are few absolute contraindications to CT-guided pleural biopsy. However, the followingpoints should be considered.

Prior to biopsy;

• Coagulation parameters should be measured. Ifthe patient has been on warfarin, the interna-tional normalised ratio (INR) should be measu-red. Any coagulopathy should be corrected. Anuncorrectable coagulopathy is a contraindicati-on to biopsy. A full blood count should also beperformed.

• Since one of the main complications of pleuralbiopsy is pneumothorax, the patient’s respira-tory reserve and therefore ability to tolerate apneumothorax should be considered. Lungfunction tests should be performed prior to bi-opsy. Biopsy is not usually performed if theFEV1 is less than 1 litre. The risk of pneumotho-rax is increased when there is little or no pleuraleffusion.

• The patient should be able to give informed con-sent. If not, consent may need to be given by re-latives or carers. A confused patient is unlikely tobe able to co-operate with the procedure and itshould not be performed in this instance.

During the biopsy;

• Biopsy should not be performed at a site ofoverlying skin abnormality such as tumour inva-sion or infection. In most cases, another site canbe chosen to perform the biopsy but if not thebiopsy should be postponed or avoided.

• The patient needs to be able to tolerate lying flatfor at least 15-30 minutes to allow the procedu-re to be performed under imaging guidance.

Technique

The exact technique used will depend on localavailability of equipment and expertise.The biopsycan be performed with or without a co-axial need-le, depending on the individual case. The techni-que described below assumes that there are nospecial facilities for CT intervention, such as CT flu-oroscopy, and describes a non co-axial technique

1. A sterile trolley should be prepared with the ne-cessary equipment (see figure 1).

2. The patient is scanned in an appropriate positi-on (supine, prone etc) according to the results ofprior imaging with the best location chosen forbiopsy. It is important that the patient is comfor-table enough to tolerate this position for the du-ration of the position. Many patients are uncom-fortable lying prone and the ‘nephrostomy positi-on’ (patient prone, target side tilted slightly up,one arm by the head, the other by the patients si-de) may be better tolerated.

3. Bearing in mind the findings of previous ima-ging, a limited scan is first performed of the ab-normal area to select an appropriate site for bi-opsy. Depending on the findings of the originalCT scan, intravenous contrast may be administe-red to help visualise the abnormal pleura. If an ap-propriate intercostal space to insert the biopsy ne-

CT Guided Pleural Biopsy

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edle is not apparent, the patient may be rescan-ned with the arms in a different position in orderto alter the relative position of the ribs and pleu-ral abnormality.

4. A CT section should be identified which allowsthe biopsy needle to be inserted immediatelyabove the rib to minimise the risk of damagingthe neurovascular bundle, and marked on the skinsurface.

5. The skin should be thoroughly cleared with an-ti-septic solution eg chlorhexidine and sterile dra-pes placed around the biopsy site.

6. Local anaesthetic should be infiltrated into theskin, the subcutaneous tissue and down to thepleura to be biopsied.

7. Limited scans (generally 1 to 7 slices dependingon the set-up of the scanner) should be performedto confirm that the needle is advanced at the cor-rect angle. When there is minimal pleural thicke-ning, the biopsy should be performed in the planeof the thickening to minimise the chance of samp-ling adjacent lung and to maximise sample size.

8. A small incision is made in the skin with a scal-pel at the entry point for the biopsy needle.

9. The biopsy needle can then be inserted, usingthe same technique of using repetitive limited CTscanning to confirm the needle position. The ne-edle is first advanced to the pleura. During the bi-opsy procedure, the patient may either be allo-wed to breathe gently or be asked to hold theirbreath on gentle inspiration.

10. The closed biopsy needle can then be advan-ced into the area of pleural thickening.

11. A repeat limited scan should be performedto confirm the needle position before taking thebiopsy.

12. If necessary, for example in very minor pleuralthickening, the needle can be opened before ta-king the sample and the position of the openedneedle confirmed with CT (Figure 2).

13. After opening, the needle may be rotatedthrough 90 degrees, and is then fired and remo-ved, in one smooth sequence of movements.

14. An assistant should apply gentle pressure atthe site of skin entry whilst the biopsy sample isexposed and placed in formaldehyde for histolo-gical analysis. If tuberculosis is considered a samp-le should also be sent for microbiological analysis.

15. A limited post biopsy scan can be performedto exclude a post biopsy haemorrhage or pne-umothorax.

Complications

There are few reported complications post imageguided biopsy. In a series of 85 CT guided pleuralbiopsies performed in a single UK centre (8) the-re was a 4.7% incidence of pneumothorax visibleon post biopsy chest x-ray and a 7.5% incidenceof bleeding although none of these had signifi-cant cardiovascular compromise. Other studieshave shown a 5-10% complication rate (9-11).

Post Biopsy Care

The patient should be instructed to move as littleas possible and avoid talking until the first post-bi-opsy chest x-ray. This is particularly important if asmall pneumothorax was identified on the postprocedure CT.

The patient should be transferred to an observati-on area for 4-6 hours post-biopsy.

Regular observations including blood pressure,pulse, respiratory rate and oxygen saturation sho-uld be performed and any alterations in the ob-servations reported to the attending doctor.

Simple Analgesia May Be Prescribed

Chest radiographs should be performed at agreedintervals, for example at 2 and 4 hours. If the 2hour radiograph shows no complication, the pati-ent may talk, eat and drink and mobilise.

If the patient is well after 4-6 hours with no signi-ficant chest x-ray abnormality they may be disc-harged home. Aftercare advice should be provi-ded for the patient.

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EJ Helm, FV Gleeson

Summary

CT guided pleural biopsy is a relatively safe proce-dure that can usually be performed as a day caseprocedure. It has high sensitivity and specificityfor identifying the cause of unexplained pleuraleffusion and pleural thickening and is preferred toblind pleural biopsy. The exact technique de-pends upon local equipment and expertise. Follo-wing the general principles detailed above shouldensure that the procedure is as safe as possibleand provides a high diagnostic yield.

CT Guided Pleural Biopsy

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Figure 2: CT of pleural biopsy-needle in open position

crossing the pleura.

Figure 1: Equipment for CT guided pleural biopsy.

REFERENCES

1. Light RW. Pleural Diseases. 5th ed. Philadelphia: Lip-pencott, Williams and Wilkins; 2007.

2. Maskell NA, Butland RJ. BTS guidelines for the investi-gation of a unilateral pleural effusion in adults. Tho-rax 2003; 58 (Suppl 2): 8-17.

3. Maskell NA, Gleeson FV, Davies RJO. Standard pleuralbiopsy versus CT-guided cutting-needle biopsy for di-agnosis of malignant disease in pleural effusions: Arandomised controlled trial. Lancet 2003: 19; 361:1326-30.

4. Salyer WR, Eggleston JC, Erozan YS. Efficacy of pleuralneedle biopsy and pleural fluid cytopathology in thediagnosis of malignant neoplasm involving the pleu-ra. Chest 1975; 67: 536-9.

5. Nance KV, Shermer RW, Askin FB. Diagnostic efficacyof pleural biopsy as compared with that of pleural flu-id examination. Mod Pathol 1991; 4:3 20-4.

6. Prakash UB, Reiman HM. Comparison of needle bi-opsy with cytologic analysis for the evaluation of pleu-ral effusion: analysis of 414 cases. Mayo Clin Proc1985; 60: 158-64.

7. Garcia LW, Ducatman BS, Wang HH. The value ofmultiple fluid specimens in the cytological diagnosis ofmalignancy. Mod Pathol 2004, 7: 665-8.

8. Benamore RE, Scott K, Richards CJ and Entwisle JJ.Image-guided pleural biopsy: Diagnostic yield andcomplications. Clin Rad 2006; 61: 700-5.

9. Adams RF, Gleeson FV. Percutaneous image-guidedcutting-needle biopsy of the pleura in the presence ofa suspected malignant effusion. Radiology 2001;219: 510-4.

10. Adams RF, Gray W, Davies RJO, et al. PercutaneousImage-guided Cutting Needle Biopsy of the Pleura inthe Diagnosis of Malignant Mesothelioma. Chest2001; 120: 1798-802.

11. Metintas M, Ozdemir N, Isiksoy S, et al. CT-GuidedPleural Needle Biopsy in the Diagnosis of MalignantMesothelioma. JCAT 1995; 19: 370-4.

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EJ Helm, FV Gleeson