while in the gun and therefore lacks an intrinsic stop to hold the trocar and cannula components in fixed relationship. To overcome these limitations, Parker et ab suggested placing a short length of the protective plastic sheath in which the needle is supplied between the hubs of the trocar and cannula to act as a fixed spacer (1,2). In our experience, awkwardness involved in slicing the sheath lengthwise with a scalpel has resulted in imprecision and subsequent difficulty

in

placement

or

removal

of the

sheath from around the trocar. We have also found that the sheath tends to slip into the hollowed-out inner portion of the cannuba hub, thereby allowing the two components to slip out of relative position with each other. The sheath may be cut longer to fit into the cannula hub, but this is somewhat less convenient.

Our holder overcomes these limitations. The fixed slots always hold the

needle securely and at the correct position, but the holder can be easily removed before confirmatory scanning or attachment of the gun. The current version

of the

Double-Lumen

this is not the trocar

holder

terms:

technology stenosis

Catheters .

Ureter,

or obstruction,

Radiology

and

catheterization,

function

study

82.843,

82.844

Ureter,

#{149}

Nuys, CA revision re-

quested April 24; revision received May 20; accepted May 22. Address reprint requests to

286

1991

#{149} Radiology

can

craftsmanship device.

thank

James

in fabricat-

References Parker

SH, Yakes

WF,

Hopper

KD, Gibson

MD. Technical note: adaptation of the Bard prostate biopsy gun for CT-guided abdominal biopsies. diol 1989; 12:50-52.

The

Ra-

3.

5.

Bogan ML, Kopecky KK, KraftJL, et al. Needle biopsy of renal albografts: comparison of two techniques. Radiology 1990; 174: 273-275. Poster RB, Jones DB, Spirt BA. Percutaneous pediatric renal biopsy: use of the biopsy gun. Radiology 1990; 176:725-727. Parker SH, Lovin JD,Jobe WE, et al. Ste-

6.

reotactic breast biopsy with a biopsy Radiology 1990; 176:741-747. Elvin A, Andersson T, Scheibenpflug

sheath be 4.

In conclusion, we believe this device allows quicker and easier performance of CT-guided biopsy procedures with the biopsy gun. We have not yet performed US-guided biopsies with this device, but we believe it would facilitate these procedures as well, particularly in the case of freehand US-guided biop-

Intervent

Parker SH, Hopper KD, Yakes WF, Gibson MD, OwnbeyJL, Carter TE. Image-directed percutaneous biopsies with a biopsy gun. Radiology 1989; 171:663-669.

be sterilized;

saved.

Cardiovasc

2.

nee-

removal.

Lindgren

a biopsy

PG.

Biopsy

gun. Radiology

of the

gun. L,

pancreas

with

1990; 176:677-679.

#{149}

Venous

Catheter

Perfusion ureterab (Whitaker

Studies’

perfusion

HE

test)

examination

for

urinary tract of noninvasive

obstruction when results tests are inconclusive.

Various

techniques

performance

diagnosis

have

been

needle

used

sures. in

test. The with a

may

skinny

catheter for perfusion studies. This type of catheter is commonly employed to allow simultaneous infusion of fluids and measurement of intravascular pres-

of upper

of the Whitaker be performed

examination

single

the

study

(1) is a valuable

Materials

catheter, but this requires intermittent interruption of the infusion to measure intrarenal pressure. Simultaneous infusion and pressure monitoring through single lumen allows rapid recognition

a of

elevated pressures and shortens procedure duration; this also requires the use of a 14-gauge needle or 12-F catheter, however, because of the high pressure differentials caused by smaller caliber at the

flow

rates

used

for

of two

parallel

has been

perfusion

(3).

22-gauge

used

The

needles

to study

maximum

in

ureteral diameter

and Methods

Ureterab perfusion was studied in three pediatric patients less than 1 year of age. We used a set (Figure) (Cook, Bloomington, Ind) that includes a 15-

or small-lumen

the test (2). Use of two needles or catheters also allows concurrent infusion and monitoring but necessitates an additional renal puncture. A double-lumen needle consisting

I From the Departments of Radiology (M.J.D.) and Pediatrics (J.C.K.), Valley Presbyterian Hos-

M.J.D. C RSNA,

and

The authors

Howerton for expert ing the needle holder

1.

because their after

holder

is reusable

essentially

pital, 15107 Vanowen Blvd. Van 91405. Received March 19, 1991;

point, maintain

relationship

and

instruments

1991; 181:286-287

to leave

the time spent preparing a new for each procedure can therefore

T

A commercially available double-lumen central venous catheter that can be inserted over a 0.018-inch guide wire was used for ureteral perfusion studies in three infants. Complications or difficulties were not encountered in any patients. This technique allows simubtaneous monitoring of perfusion and intrarenal pressure and requires only a single puncture of the renal pelvis with a 21-gauge needle. Index

and

dle placement

Ureteral

Michael J. Diament, MD John C. Koenig, Jr, MD

heavy

an important and cannuba

orientation

Central

Percutaneous

is too

in place while scanning the patient to check needle position; we plan to devebop a smaller, lighter holder that can be left in place. In practice, however,

sies.

for

holder

Acknowledgment:

cm-long

5-F double-lumen

catheter,

a

0.018-inch guide wire, a 6-F vascular dilator, and a 4-cm-long 21-gauge needle. Each catheter lumen has a diameter equivalent to that of a 20-gauge needle. These catheters are available in lengths of 5-25 cm and calibers of 4.0-7.5 F and may be ordered separately if the full set is not required. Similar designs are

available from other manufacturers. Renal puncture was performed with the 21-gauge needle but can be performed with a longer needle if necessary.

After

confirming

proper

position-

ing by injection of contrast medium (Hypaque Meglumine 3%; Winthrop,

of this instrument, however, is equivabent to a 17-gauge needle, and the device is not commercially available. To avoid the drawbacks associated with these techniques, we employed a

New York), standard technique used to place the double-lumen within the pelvis or proximal

avoided bypassing any potential obstruction. The external portion

site of of the

standard

catheter

with

double-lumen

central

venous

was

secured

to the

was catheter ureter. We

skin

October

1991

a.

b.

(a) Components

of the catheter

set, from

top to bottom:

guide wire. Port 1 connects to the end hole side-hole port used for obtaining manometric

and

sterile

tape. The end-hole lumen was connected to a pump, and the side-hole lumen was connected to a water manometer. Infusion of dilute contrast medium was observed fluoroscopically, and bladder pressure was monitored simultaneously through a 5- or 8-F feed-

ing-tube

catheter

connected

to another

manometer.

If conversion

to nephrostomy

age is desired, the guide wire can reinserted prior to removal of the

ter. A skinny-needle be used to place pelvis or ureter.

access

drainbe cathe-

set can then

a 0.038-inch

wire

in the

Results

We encountered difficulties

monitoring

Volume

no complications

in insertion

of the

of intrarenal

181

#{149} Number

pressure,

1

or

catheter,

or

21-gauge

port 2 connects measurements.

infusion

puncture to the

at rates

side

of up

needle, hole.

vascular Scale

to 10 mL/min.

We have also successfully tested this catheter in vitro at infusion rates of up to 30 mL/sec. Discussion The small double-lumen pears to combine many tages of skinny-needle

dilator,

double-lumen

is in centimeters.

catheter apof the advanpuncture with

the convenience and reduced procedure time of simultaneous pressure monitoring and infusion. Constant monitoring allows the infusion to be terminated as soon as intrarenal pressure becomes abnormally elevated. Although the 5-F catheter has an outer diameter equivalent to that of a 16-gauge needle, the actual renal puncture is made with a 21-gauge instrument. Placement of a catheter rather than a single needle does require additional time, but the duration of infusion

catheter,

(b) Double-lumen

and

monitoring

catheter

instead

0.018-inch catheter

J-tipped

tip

with

is shortened.

Use

of a needle

also de-

of a

creases the disbodgment.

potential risk of accidental We have not yet had the opportunity to use this technique in older children or adults, but we anticipate no difficulty if needles and catheters of appropriate length are used.

#{149}

References 1.

2.

Whitaker struction 45:15-22. Amis EH sistances ureteral

RH. Methods of assessing in dilated ureters. Br J Urol Jr. Pfister of various perfusion.

ob-

1973;

RH, Newhouse RH. Rerenal instruments in Radiology 1982; 143:267-

268.

3.

Epstein DH, Hunter DW, Coleman CC, et al. Double-lumen needle for percutaneous ureteral pressure-flow studies. Radiology 1989; 172:569-570.

Radiology

#{149} 287