Letters U

“CT

to the

Angiogram

Differential

Sign”:

Editor

Establishing

the

Diagnosis

From: Michael R. Schuster, MD, and Kathleen A. Scanlan, MD Department of Diagnostic Radiology, University of Wisconsin Hospitals and Clinics 600 Highland Avenue, Madison, WI 53792 Editor:

We have read with interest issue of Radiology by Im el

the

article

(1) and

the

in the

September

subsequent

1990

discussion

of

an associated entity by Walkey (2) in the March 1991 issue. Both Im et al and Walkey describe enhancing pulmonary yessels

in the

midst

of completely

consolidated

pulmonary

paren-

chyma

on dynamic computed tomographic (CT) scans of the as the “CT angiogram sign.” Examples of bronchioboalveolar cell carcinoma and pneumococcal and tuberculous pneumonia were illustrated. We have recently observed a similar appearance in a patient with bymphoma.

chest

Dr Im and colleagues (1) have eloquently described the CT angiogram sign in bronchioloalveolan carcinoma while illustrating several other conditions in which the sign is present. Dr Wabkey (2) has submitted another condition in which it is seen. Our example of pulmonary necrosis, probably secondary to bymphomatous involvement, serves to reinforce the point that radiologic signs and findings are rarely diagnostic of a single condition but produce a list of possible diagnoses. The more specific the sign, the shorter the differential diagnosis. The finding of totally consolidated lung, without air bronchognaphy, and with continued perfusion is uncommon and should lead to a limited differential diagnosis.

References 1. 2.

S

Im J-G, Han MC, Yu EJ, et at. Lobar bronchioloalveolar carcinoma: “angiogram sign” on CT scans. Radiology 1990; 176:749-753. Watkey MM. And what is your sign (letter)? Radiology 1991; 178: 894.

Homemade

Snare

for Removal

of Foreign

Bodies

From: George G. Hamtnell, FRCR Department of Radiology, 185 Pilgrim Road, Boston,

New England MA 02215

Deaconess

Hospital

Editor: In the March 1991 issue of Radiology, Dr Yedlicka and cobleagues (1) report on use of a nitinob gooseneck snare (Microvena, Vadnais Heights, Minn) and describe a high-tech solution to a still relatively uncommon problem. One wonders if the majority of interventional radiologists will find it necessary or cost-effective to keep a full range of these snares in stock or whether they would be better served by making their own snares, depending on the clinical situation with which they are

presented. Homemade

Contrast-enhanced sign of enhanced

lung. This portion cavitation.

A 77-year-old

CT scan

of the

chest

shows

the

CT angiogram

vessels within necrotic (liquid), noncavitated of the right lower lobe ultimately underwent

woman

with

a history

of treated

large

cell lym-

phoma was referred for dynamic contrast material-enhanced CT of the chest to evaluate a right pleural effusion. The patient did indeed have a right effusion, but, in addition, the right lower

lobe

was

compbetely

consolidated

with

the

CT

angio-

gram sign (Figure). Much of the lobe underwent cavitation, and the patient died soon after. Postmortem examination showed fibrosis and scarring in the area of cavitation as well as liquefactive necrosis of much of the remainder of the lobe. Although large cell lymphoma was not recovered from the necrotic lobe, multiple lymph nodes showed similar necrosis and were thought to represent lymphomatous foci that responded to chemotherapy.

(2) and

devices

have

been

devices guide.

described

commercially

available are

produced

for a long

relatively

stiff

time. and

can

(3,4)

The be

retrieval

majority difficult

of the to

In addition, it may be difficult to retrieve an eccentrically positioned intravascular fragment with these devices. This is one situation in which the nitinol gooseneck snare may be advantageous. It is, however, possible to produce a homemade snare that will also grasp eccentrically positioned fragments and that can be modified to fit the contours of the vessel in which a fragment has become lodged. Such a snare can be assembled from an appropriately shaped diagnostic angiographic catheter and guide wire. The catheter shape should be chosen to allow cannulation of the vessel where the intravascular fragment has lodged. In this respect, a cobra or Judkins right coronary-shaped catheter will often be most appropriate. With a small-diameter (ie, 0.015-inch), fixedcore guide wire, even diagnostic catheters with small diameters can

be

used,

providing

they

have

a 0.035-inch

internal

diame-

ten. The

assembly

and

use

of such

a snare

is illustrated

in the

fob-

bowing case. During attempted antegrade cannulation of a common femonal artery before superficial femoral artery dilation, a Radiofocus guide wire (manufactured by Temumo, Piscataway, NJ; distributed by Medi-tech/Boston Scientific, Watertown, Mass), commonly referred to as the “Glidewire,” was used through a one-piece thin-wall needle. During manipulation, a fragment of hydrophffic coating from the guide wire

903

became detached from the wire, although no resistance was felt, and was seen to pass distally into a branch of the deep femoral artery. It was believed that the fragment of coating should

be removed

A snare

to prevent

was constructed

thrombosis

with

of that

a 5-F cobra

used or the introducer ter or dilator. Variations both foreign

artery.

catheter

and a

exchange

0.015-inch fixed-cone guide wire bent loop. To prevent an excessively tight

to provide an eccentric angle forming at the apex of the snare-which could weaken the wire-the two ends of the guide wire were introduced into the patient-end tip of the diagnostic catheter and advanced until approximately 2 inches

of the looped end

guide

wire

of the catheter.

remained

At this

projecting

stage,

both

free

boplasty

of the

may

procedures

(5). The

devices

be necessary

dures are frequently structed from readily

catheter. The snare and catheter were introduced via a 6-F anterial sheath with a hemostatic valve. The snare was advanced to the level of the fragment of guide wire coating (Figure). The

ments.

fragment

was

grasped

catheter.

The

fragment,

with

the

snare,

snare

and

and

withdrawn

catheter

were

into

then

the

this

during fragment

particular

procedure,

of coating

wire

guide

became

is required,

but,

in spite

detached.

When

an alternative

design

of this,

angiography

a barge

2.

been

used

the

for

ends

aortic

of snare

made

performed, available

usually

foreign

of

valvu-

has

body

in which

a homemade materials used

suffice

JW, Canison

for

departments

the

in most

JE, Hunter

removal

these

proce-

snare confor diagnostic

angiography

depart-

DW, Castaneda-Zdniga

GH, eds. Interventional radiology. Philadelphia: 384. Curry JL. Retrieval of detached intravascular

3.

fragments:

be

type

a cathe-

with

WR, Am-

platz K. Nitinot gooseneck snare for removal of foreign bodies: experimental study and clinical evaluation. Radiology 1991; 178: 691-693. Kadir S, Athanasoulis CA. Percutaneous retrieval of intravascular foreign bodies. In: Athanasoulis CA, Pfister RC, Green RE, Robenson

a bow-resistance

of wire should

will

References 1. Yedlicka

removed

intact via the sheath, and angioplasty was completed without further complications. The Glidewime seems to be used frequently through cutting needles in spite of the manufacturer’s specific warnings against doing this. Apparently no resistance to manipulation was felt

use of this

specially

in barge

were projecting from the hub end of the catheter, allowing withdrawal of the snare. The snare was withdrawn into the catheter until only ‘/2 inch of loop projected from the tip of the wire

be replaced

of this form of steerable snare have body retrieval and also for grasping wires used during antegrade transeptab

Although

guide

should

advantage that the components are readily available in the majority of angiography departments, and the size and curve of the snare can be modified to take account of the anatomy involved in a particular situation.

from the patient ends

needle

a proposed

method.

AJR 1969;

Saunders, catheters

extraction of catheter vessels. AJR 1971;

111:467-472. Crook R, Weston M, Wilde RPH, Hantnell GG. Aortic comparison of the techniques and results of transeptal grade methods. Clix Radiol 1990; 42:110-113.

5.

U

Periodic

Benign

Follow-up

Mammographic

or guide

105:894-896.

Dotter CT, Rosch J, Bilbao MK Transluminal and guide fragments from the heart and great

4.

1982;

valvoplasty: and retro-

of Probably

Lesions

From: Clinton Department

B. Sayler, MD of Radiology,

Medical Center 1015 Northwest

Good

Samaritan

Avenue,

22nd

Hospital

Portland,

and

OR 97210

Editor: I am responding to the article by Sickles (1) in the May 1991 issue of Radiology. Congratulations to Dr Sickles on his tenacity in the follow-up of “low-suspicion” lesions. He has answered some

questions,

but

raises

others.

Of particular interest are the 1,853 cases of tiny calcifications that made up approximately 58% of the lesions. My question whether calcifications too small to be seen on regular screenfilm mammograms

is

are significant.

The percentage of mammograms Dr Siddes designated as showing “probably benign” lesions (11.2%) is higher than that found in other studies he cited (ie, Helvie et al [2], 5.4%; Wolfe, et a! [3], 6.4%). I believe that some of the higher percentages were due to tiny calcifications, which most of us do not follow up. There were two malignancies in the 1,853 cases of tiny calcifications, so they were indeed very low in suspicion. An analysis of these calcifications because it would contribute to our

cations. sions

bowed

if there into

were

a benign

a pattern, category

would be of great benefit knowledge of benign calcifi-

then that

we could

would

not

place

need

these

be-

to be fob-

up.

mammographers have considered malignant to look like grains of sand or small irregular spicubated or branching calcifications. The size of these “sand particles” as resolved with traditional mammography is beHistorically,

calcifications

tween

proved Radiograph

shows

a position

tended

to encircle

holding

904

that

just proximal the

loop

Radiology

#{149}

the

guiding

the fragment. stationary

catheter

to the detached enabled

has

fragment

Advancing the

been

and

the catheter

fragment

advanced

the loop

while

to be snared.

to

ex-

0.3 and

is improved solving

1.5 mm.

generators,

to approximately

aluminum

ogy-approved

With

the advent

and microfocus specks

phantom

0.24 mm with

an

[Radiation

of magnification, imthe resolution (as determined by re-

x-ray tubes, American

College

Measurements,

of RadiolMiddle-

ton, Wis]). December

1991