progression

of quadriparesis

was

caused

by placement spinal cord

of the needle close to the (8). Biopsy performed by means of the transpedicular route must be undertaken with care because nerve roots are close to the pedicle (Fig 4). Obtaming repeat CT scans demonstrating that the needle lies within the central portion of the pedide, along with care-

1.

Robertson RC, Ball RP. Destructive lesions: diagnosis by needle biopsy. Joint Surg [Am] 1935; 57:749-758.

2.

Siffert

3. 4.

5.

lumbar

6.

spine

plane

is described

mended in selected cases lesion is in a poor position rolateral approach. U

in which

and

is recom-

Index

terms:

Computed tomographic (CT) Computed tomography (CT), #{149} Biopsies, technology, 22.126, #{149} Orbit, CT, 22.1211 #{149} Spine, intervertebra! disks, 336.1211 guidance technology 336.126

#{149}

Radiology

1991;

180:576-578

Bonejoint

Surg

[Am]

10.

LA, Lukeman JM, Wallace 5, JA, Ayala AG. Percutaneous needle biopsy of bone in the cancer patient. AJR 1978; 130:641-649. Stoker DJ, Kissin GA. Percutaneous verbiopsy:

P

a review

of 135 cases.

ERCUTANEOUS

biopsy

procedure

puncturing

with

precise small

target

is diskography. Performing it CT allows the advantage of direct

visualization

of the

disk

space

and

bet-

ter evaluation

of contrast-agent distribution and tears in the anulus fibrosus. Also, it is easier for patient and operator alike when the procedure is performed in one setting rather than puncturing the skin with fluoroscopic guidance and subsequently

performing

a CT examina-

lion. A wide range of devices and instruments are used for CT-guided punchires, depending on the region in queslion (eg, thorax, liver, or cervical spine), and procedures vary considerably. Some methods require affixing a device to the patient or instaffing additional hardware besides the CT scanner (1-7). Some involve CT only for visualization of the target area, with the puncture being performed by hand guidance Procedures

taking

into

account

a gantry tilt other than 0#{176} are seldom described (11,13). To overcome these impediments, a device designed with the aim to perform precise punctures

December accepted

27; revision received March 27, 1991; April 1. Address reprint requests to C.o., Abt Neuroradiologie, Radiologische Klinik, Hoppe-Seyler-Str 3, 7400 Tubingen, Ger-

safely

many. 0 RSNA,

punctures incorporated

576

Radiology

#{149}

12.

and

was operation tine,

closed

bi-

biopsy of the Proc 1986; 61:

Frager DH, Goldman MJ, Seimon LP, et a!. Computed tomography guidance for skeletal biopsy. Skeletal Radiol 1987; 16:644-646. Brugieres P, Gaston A, Heran F, Voisin MC, Marsault C. Percutaneous biopsies of the thoracic spine costovertebral Tomogr 1990;

13.

EVA, Silao JV,

opsy of the spine. J Comput Assist Tomogr 1981; 5:73-78. Mick CA, ZinreichJ. Percutaneous trephine bone biopsy of the thoracic spine. Spine 1985; 10:737-740. Bender CE, Berquist TH, Wold LE. Imag-

under CT guidance: approach. J Comput 14:446-448.

trans.. Assist

Fidler MW, Niers BBAM. Open transpedicular biopsy of the vertebra! body. J Bonejoint Surg [Br] 1990; 72:884-885.

Materials

performed

requiring

of a relatively

(1,8-14).

BD, Lim CT-guided

Punctures’

From the Departments of Neuroradiology (CO., Ky.) and Medical Physics (F.N.), Radiological University Clinic, Tubingen, Germany. From the 1990 RSNA scientific assembly. Received November 19, 1990; revision requested

1991

11.

Clin

with computed tomographic (CT) guidance has become a common procedure for diagnostic and therapeutic interventions in most regions of the body. In neuroradiology, an example of a

structure

A.

1985; 36:569-577.

Percutaneous

common

BD, Legada

ing-assisted percutaneous thoracic spine. Mayo Clin 942-950.

deSantos

CT-targeted

A device for computed tomography (CT)-guided percutaneous punctures that is not affixed to the patient and can be used even when the gantry is tilted was developed and tested. In initial patient examinations, the device was accurate within 1.0 mm of the predetermined target point. Experience so far has involved retrobulbar anesthesia and puncture of intervertebral disk space.

9.

Murray

7.

Christoph Ozdoba, MD Karsten Voigt, MD Fridtjof N#{252}sslin, PhD

bi-

1531-1544.

in which the for the poste-

for

bone

to the lumbar

Vertebral trephine biopsy. Ann Surg 1956; 143:373-385. Ackermann W. Application of the trephine for bone biopsy. JAMA 1963; 184:1117. Ottolenghi CE. Aspiration biopsy of the spine. J BoneJoint Surg [Am] 1969; 51:

Radiol

Device

Trephine

reference

Adapon

Dalmacio-Cruz

spine J Bone

1949; 31:146-149. Ackermann W.

tebral

New

AM.

bodies. J

vertebral

the

to the

RS, Arkin

opsy with special

needle passes, is essential to safe biopsy with this technique. In conclusion, a transpedicular approach to biopsy of the thoracic and

ful attention

8.

References

fast,

that

is, in

clinical

rou-

developed and tested. Easy and the abifity to perform with the gantry tilted were into the design.

and

Methods

CT-guided punctures with the device presented here were performed with a Somatom DR-H (Siemens Medical Systems, Erlangen, Germany) third-generation CT scanner. The device is mounted on two parallel rails on top of the gantry

(Fig

1). The

needle

guide

can

be

moved in left/right and up/down direclions, representing the x and y axes in an axial CT scan. The needle carrier (Fig 2) permits

angulation

of the

needle

in

the axial (scan) plane and along the plane of the patient table. We use a commercially available disposable needle holder originally designed for ultrasound-guided punctures (Needle Guide Kit MST no. 2; Amedic, Stockholm) that can carry 0.7-2.5-mm needles. When the gantry is tilted, the device moves with it. It remains on the CT scanner and does not affect normal routine imaging, no other hardware, especially any installation directly on the patient, is required. When the target point is located on an axial CT scan, the trajectory along which the needle is to be pushed forward is determined. Critical structures such as vessels, muscles, or nerves must be avoided. A starting point outside the patient’s body along this path is Selected. The coordinates of start and target points are entered into a computer program that performs the coordinate transformations,

including

corrections

for gantry tilt, if necessary. The program can be used on any IBM-compatible machine and can easily be changed to comAugust

1991

Figure

1.

Stereotaxic

device

mounted

on

Somatom DR-H scanner. Scales are at the top front of the gantry (x-axis direction), with a magnifying

glass

to improve

on the vertical extension (y-axis direction).

readability,

and

of the needle

guide

Figure

3.

gantry

tilted.

Phantom

CT studies

(b) Intended

in a lumbar

trajectory

spine

The physician performing the examination adjusts the device accordingly and inserts the needle for diagnostic or therapeutic purposes to the calculated length. To do this, the patient table is moved to the needle carrier’s position, that is, out of the scanning plane. Immediately after the procedure, the result can be controlled with another CT scan. Depending on the stability of the necdle’s position (depth), the needle can be removed from the needle guide or the scan can be obtained with the needle in place. The prototype built in mid-1989 underwent

extensive

phantom

tests

(Fig

3) to determine the relationship between the internal coordinate systems of the device and scanner and to ensure sufficient reliability and accuracy in punctures. Phantom studies resulted in an accuracy of ±0.5 mm so that patient examinations

could

be performed

safely. Written informed obtained in all cases.

consent

was

The first procedures

Figure 2. Needle carrier. The puncture necdle in a sterile holder with grooves is fitted to the part extending to the right. Magnifying lenses improve reading the degree scales in both axes.

ply with sions)

hardware

of other

constants

CT scanners.

(dimenThe

coordinates for adjustment of the punchire device in x and y directions, angulation of the needle guide, and depth of needle insertion are either displayed on the computer screen or directed to a printer. Angulation of the intended trajectory

is automatically

displayed

on

the

screen of the CT scanner, and the depth of needle insertion can easily be estimated with the scale displayed on the CT image. Comparison of these values with those calculated by the computer serves Volume

as an additional 180

Number

#{149}

safety

2

feature.

device

performed

in punctures

of orbit

with and

the

maximal

of axial

section

with

obtained; the patient will probably be operated on soon. In retrobulbar anesthesia, 0.5 mL of a nonionic contrast agent was diluted in the anesthetic for visualization of the extent of intraorbital distribution; the clinical aspects are reported separately (15). Ensuring

immobility

of the

patient’s

head during the procedure is, from experience gathered so far, relatively easy.

Puncture

of a small

tumor

the

deep

in

the orbital cone was performed successfully (Fig 4); for punctures in the lumbar region, however, improvement in the stability

of the

patient’s

position

seems

desirable.

Discussion CT-guided

punctures

structures

for

diagnostic

purposes

have

become

dures

deviation

of the

greatly safety

intervertebral disk space were successful, with high accuracy in reaching the target point. Twelve punctures of the lumbar vertebral disk space (n = 5) and orbit (n = 7) were performed. In all cases,

(a) Plane

in situ after puncture.

in most

of soft-tissue or

therapeutic

routine

radiologic

proce-

departments.

Direct visualization of an intracorporeal target structure permits the use of a mechanical puncture device, thereby

Results this

specimen.

and (c) needle

nec-

dle tip from the target point was 1 mm at maximum needle insertion depths of approximately 7 cm. Examination included diagnostic scans to determine the target point, calculation of coordinates, puncture, and final control scans to visualize the results; the average time was 45 minutes. Indications for use so far have been retrobulbar anesthesia in patients with long, myopic eyeballs, lumbar diskography (which was combined with CTguided nucleotomy in one patient), and needle biopsy of an orbital cone mass. In this case, CT could not allow differentiation between tumor and inflammalion. The latter was ruled out with cytologic examination of the material

improving

accuracy

in comparison

with

and

patient

hand-guided

procedures (6). The devices described so far are quite different: Some contain components that have to be affixed to the patient (2,3); others have to be mounted beside the CT scanner (1,4). In the clinical routine, this is time-consuming and might reduce patient throughput in a CT unit. Most techniques that have been described involve CT scanfling only for determination of the target area and trajectory from the skin to the target. The puncture, however, is performed by hand guidance (8-14). Though this modus operandi is reasonably applicable in, for example, puncture of a liver abscess and yields satisfactory

results

(8,10,12),

it does

not

have

the advantages in anatomic information and accuracy that are inherent in a 2- or 4-mm axial CT scan and excludes small structures

from

being

punctured

this

way. For use in regions such as the lumbar spinal canal, where disk-space parallel scanning is impossible without Radiology

577

#{149}

gantry

tilt,

the

device

the necessary

should

perform

coordinate

transforma-

experience

gathered

tions.

The clinical

so

far leads to the following criteria for an optimized CT-guided puncture device: high degrees of accuracy and precision, speed and ease in use, and easy availability without additional installations. Achievement of great accuracy, which is mostly a mechanical problem, is an absolute must for interventions in critical regions like the orbit. Patient stability is an important factor for both safety and precision. Reduction of examination time is a step toward this; combined

with

easy,

preferably

computer-

ized handling of the device, improve patient safety. High-precision

vices have

that been

surgical

it helps

computer-guided

fulfill these described biopsies

de-

requirements for use in neuro-

(16-18);

these

however,

inevitably demand rigid frame to the patient’s device presented here will,

experience, head and

devices,

bolting a head. The after initial

probably be used spine. The transfer

in the of data

of the device

pound-angle

needle

tions

carrier

and

1.

2.

3.

Apart from present experience in the spine and orbit, the design and construction of the device theoretically permits use for punctures in the thorax, abdomen, and pelvis as well. Practical

necessary

ing abdominal organs would lead to an increase in needle lion. U

4.

5.

6.

7.

Onik body opsies. Onik body

G, Costello P. Cosman stereotaxis: an aid for AJR 1986; 146:163-168. G, Cosrnan E, Wells T, stereotaxic system for

arrays.

8.

(a) Intended

Oncol

9.

Brugieres

Marsault

P, Gaston

C. spine

Tomogr Hammers

A, Heran

Percutaneous under

Acta

NS. and

CTcathe-

1990; 14:446-448. LW, McCarthy

al. Computed percutaneous

F, Voisin

biopsies

CT guidance:

approach.

13.

J Comput 5, Williams

of the trans-

eyeball

Welch TJ, Sheedy PF, Johnson CD, Johnson CM, Stephens DH. CT-guided biopsy: prospective analysis of 1,000 procedures. Radiology 1989; 171:493-496. Yueh N, Halvorsen RA, Letourneau JG, Crass JR. Gantry tilt technique for CTguided biopsy and drainage. J Comput Assist Tomogr 1989; 13:182-184. ZentnerJ, Hassler W. Closed biopsy of

the spine Acta

using

a stereotactic

Neurochir

C, Voigt K.

Wien

Ozdoba

16.

dungsbereiche CT-gesteuerter perkutaner stereotaktischer punktionen in der neuroradiologie. lOin Neuroradiol 1991; 1:58-63. Benabid AL, Cinquin P, Lavalle S, Le Bas

JF, Demongeot puter-driven

17.

Technik

biopsy for1988; 94:155-

15.

18. MC,

between

thickening in the cone shows very small hypoattenu-

opsy: the Yale experience. Yale J Biol Med 1986; 59:425-434. Levine ML, Hall FM. Gantry angulation for CT-guided biopsy or aspiration (letter).

ceps. 157.

Biol Phys

system.

trajectory

AIR 1989; 152:1345-1346. 12.

14.

et al. CT placement of

stereotactic

11.

CT bi-

ter drainage of pyogenic liver abscesses. Am J Gastroenterol 1986; 81:550-555.

10.

Radiology

mt I Radiat

rotary

costovertebral

#{149}

tumor.

biopsy Invest

E, et al. CT-guided

Neurochir Wien 1983; 68:19-26. Attar B, Levendoglu H, Cuasay guided percutaneous aspiration

thoracic

578

cone

1987; 13:121-128. Onik G, Cosman ER, Wells TH, et al. CTguided aspirations for the body: comparison of hand guidance with stereotaxis. Radiology 1988; 166:389-394. Patil AA. Computer tomography (CT)

orientated

in puncturprobably devia-

of an orbital

Frederick PR, Brown TH, Miller MH, Bahr AL, Taylor KH. A light-guidance system to be used for CT-guided biopsy. Radiology 1985; 154:535-536. Hruby W, Muschik H. Belt device for sirnplified CT-guided puncture and biopsy: a technical note. Cardiovasc Intervent Radiol 1987; 10:301-302. Onik G, Cosman ER, Wells T, Moss AA, Goldberg HI, Costello P. CT body stereo-

needle

has

and abdominal organs are subject to respiratory and peristaltic motion, the high degree of accuracy that can be achieved in static structures (head, spine) would most likely not be reproducible in these organs. In addition, the

trajectories

biopsy

taxic instrument for percutaneous and other interventive procedures. Radiol 1985; 20:525-530.

in all direc-

automatically.

longer

Needle

and lateral wall of the orbit. Target point is the small isoattenuated near the lateral rectus muscle. (b) Control image after puncture ated inclusion of air (between arrows) in the target area.

the com-

experience in these fields, however, not yet been established. As thoracic

b. 4.

References

necessary now (CT console -#{247} personal computer printed results puncture device), which is time-consuming and error-prone and requires numerous cross-checks for safety reasons, will be reduced in an improved version that is being developed. The aim is to adjust

the positions

a. Figure

und anwen-

J, de Rougemont J. Comrobot for stereotactic surgery

connected to CT scan and magnetic resonance imaging: technological design and preliminary results. Appl Neurophysiol 1987; 50:153-154. Goerss SJ, Kelly PJ, Kall BA. Automated stereotactic positioning system. Appl Neurophysiol 1987; 50:100-106. Lunsford LD, Listerud JA, Rowberg AH,

Latchaw RE. Stereotactic software for the GE 8800 CT scanner. Neurol Res 1987; 9:118-122.

Assist H, et

tomographic (CT) guided fine-needle aspiration bi-

August

1991