Letters

to the

U Skull Radiography Head Trauma

in the

Editor Evaluation

of Acute

From: Ferris M. Hall, MD Department of Radiology, Beth Israel Hospital Medical School 330 Brookline Avenue, Boston, MA 02215

and

Harvard

Editor: In the December 1991 issue of Radiology, Hackney (1) reports the results of a survey conducted to determine the extent to which skull radiography continues to be performed for evalualion of acute head trauma. He concludes that “skull radiography continues to be employed at a high rate for the evaluation of head trauma long after it has been demonstrated to provide little or no useful information in such cases.” Hackney then states that “since radiologists will rarely refuse to perform skull radiography, our opportunities for correcting this

overuse

are

limited

and

the

responsibility

for

addressing

appropriate radiologic evaluation of head trauma will remain with the referring clinician.” My small anecdotal experience is more optimistic about the role radiologists can play in curtailing the number of posttraumatic skull radiographs obtained, as well as other apparently unindicated radiographic studies. I begin or end my reports of such examinations with the statement, “The clinical indications for this examination are unclear to me.” It is surprising how often this statement is eventually seen by, or brought to the attention of, the referring physician and how often that mdividual subsequently contacts me. This gives me the opportunity to explain why skull radiography provides little or no information

these

in acute

clinicians

head

with

trauma.

a copy

In the

future

of Dr Hackney’s

I will

provide

article.

Reference 1.

Hackney trauma:

DB. Skull radiography in the evaluation of acute head a survey of current practice. Radiology 1991; 181:711-714.

mography Accreditation Program (MAP). In fact,four different versions of the RMI-156 mammographic phantom insert have been observed, and phantom reviewers routinely note on the review form which insert version is being reviewed. Images of these four different versions of the inserts alone (without the acrylic holder and coverplate) are shown in the Figure. Version 1 of the RMI-156 insert (Figure, part a) had the third and fourth fibers running vertically and horizontally, parallel to the edges of the phantom. This was problematic because of the instructions for placement of the phantom, which called for the edge of the phantom to be parallel to the chest wall of the image receptor. This led to alignment of the fourth fiber with grid lines when a grid was used, sometimes causing the fourth fiber to be obscured by fixed grid lines in this particular orientation; a slight rotation of the phantom would render the fourth fiber still visible. This was corrected in all subsequent versions

parts b-d). The other entiated

Inconsistencies Used for ACR From: R. Edward Department Sciences

4200

Editor: In the October sizes

in two

Avenue,

1991 in the different

Cacak

is correct

of Colorado

CO

RMI-156

Cacak

mammographic

Middleton, Wis). that demonstrated in pointing

out

that

(1) pointed

out

an

versions

sizes

and

all fibers edges

at approximately

of the

of the RMI-156 distributions

phantom

insert

of specks.

(Figure,

can

be differ-

The

specks

in

unexpected

change

in the

RMI-156

phantom

insert

mdi-

phantoms

(Ra-

Dr Cacak included differences in sizes have

with

the

manufacturer,

it was

determined

that

past

in-

should be corrected and that a single version of phantom insert should be produced. This resulted in version 4 of the phantom, with the agreement that all earlier versions of the RMI-156 insert purchased through the ACR MAP would be replaced with the version 4 insert. The more consistent speck sorting process used in the version

(“speck”)

differences

three the

placing

to the

consistencies the RMI-156

Health

microcalcification

by

by

cated to those involved in the ACR MAP that variations in phantom production had occurred and that tighter quality control of phantoms was required. Consequently, through con-

80262

of Radiology,

simulated

diation Measurements, images of two phantoms of the larger specks. Dr

University

Denver,

issue

Phantoms

sensus

Hendrick, PhD of Radiology, Center

E Ninth

inconsistency

in Mammographic Accreditation

2-4) relative

the version 2 insert are similar to those in version 1 (Figure, part b). Version 3 had larger specks that were more widely distributed in each speck group (Figure, part c). This version was made because of a change in the manufacturer’s speck sorting process, which was intended to tighten the tolerance in speck sizes. This change, which occurred in the spring of 1990, also resulted in larger specks being selected in each size group. Apparent differences in speck sizes were noted immediately by reviewers in the ACR MAP and by state radiation control personnel who were using different versions of the RMI-156 insert. After further study, the pass-fail criteria for specks in the ACR MAP were immediately modified. In versions 1 and 2 of the RMI-156 insert, the speck criterion to pass the ACR MAP was to visualize at least 2’/2 speck groups (full visualization of the two largest speck groups and visualization of at least three specks in a third speck group). With the new sizes of the specks in version 3, the speck criterion to pass the phantom test was changed to require the visualization of all specks in the three largest speck groups. This

U

(versions

45#{176} orientations

oc-

curred in the production of the RMI-156 mammographic phantorn. Several changes in test objects contained within the RMI156 phantoms have been observed by the phantom image reviewers in the American College of Radiology (ACR) Mam-

3 insert

was

continued,

but

nominal

speck

sizes

were

in-

tentionally changed in version 4 to diameters of 0.54, 0.40, 0.32, 0.24, and 0.16 mm for the five speck groups (Figure, part d). The placement of all test objects in the phantom, such as the distribution of specks and the orientation of fibers, was also standardized in version 4. Quality control procedures for ensuring the uniformity of insert production were also improved. Version 4 inserts are most easily identified because there is an aluminum plate with a unique identification number embedded in each insert. The sizes of fibers and masses in version

581

b.

a.

d.

C.

Images

of RMI-156

version

1 (a), 2 (1,), 3 (c), and

4 (d) phantom

inserts.

4 inserts and the criteria used for fibers and masses in the MAP are unchanged from the previous versions of the RMI-156 phantom. The criteria that apply to version 4 are that the largest four fibers, the largest three speck groups, and the largest three masses should be visualized to pass the phantom component of the ACR MAP. Dr

Cacak

pointed

out

the

difference

in speck

sizes

between

versions 3 (shown in his Figure, part a) and 4 (his Figure, part b) of the RMI-156 insert. All RMI-156 phantoms currently being produced contain the version 4 insert. The ACR MAP recommends that version 1, 2, or 3 inserts in older RMI-156 mammographic

phantoms

manufacturer 582

#{149} Radiology

be

replaced

has agreed

with

to provide

a version

replacement

4 insert.

inserts

The

to

ACR MAP participants at no cost. Because the process of assembling phantom inserts is slow and tedious, production rates for the version 4 insert are limited. Therefore, it is recommended that radiologists at ACR-accredited sites replace their version 1, 2, or 3 inserts as they approach reaccreditation so that all accreditation testing is performed with the version 4 insert. The use of a phantom test object standardized so that it is uniform from site to site is one of the essential elements of the ACR MAP. Other quality control elements of the MAP include the review of personnel credentials, equipment specifications, clinical image quality, dosimetry, and processor quality control. This experience with variations in the phantom has shown that

May

1992

and

control

phy depends critically on including rigorous quality

the desire

quality control

test

to improve

equipment

used

in the

the quality control

of mammogra-

of the

of the test

program

itself,

procedures

and

program.

Reference 1.

Cacak RK. Inconsistencies ACR accreditation (letter).

in mammographic Radiology 1991;

phantoms 181:288-289.

used

for

parent at fluoroscopy, and if we had not rectally administered contrast material, the sigmoid colon would have been punctured inadvertently. The procedure was abandoned, and the patient underwent surgical gastrostomy. We have performed 360 gastrojejunostomy procedures, and only one case of colonic perforation occurred. This is the first time that we have seen this configuration of sigmoid colon overlapping the stomach, and we believe that a knowledge of this

possibility

may

prevent

inadvertent

moid colon. If doubt exists and verse colon cannot be visualized, rectally administered.

U Infracolonic

Percutaneous

puncture

References

Paul Ignotus, FRCS (Edin), FRCR, Robin Gray, MD, FRCPC, and Robyn Pugash, MD, FRCPC Department of Radiology, Wellesley Hospital 160 Wellesley Street East, Toronto, Ont M4Y 1J3, Canada

1.

Halkier BK, Ho CS, Yee ACN. with the Seldinger technique: 1989; 171:359-362.

2.

Cray RR, St Louis EL, Crosman H. neous gastrojejunostomy. Radiology

3.

Minch DR, Cray RR. Infracolic percutaneous technical note. Cardiovasc Intervent Radiol

Editor:

Percutaneous gastrojejunostomy has become a well-recognized and much used method of enteral feeding (1,2). Recently, we have described an infracolonic approach when the transverse colon overlaps the stomach (3). We have just come across an unexpected contraindication to this approach, an awareness of may

prevent

the

potential

complication

of colonic

perfo-

U Progression Diagnostic

A 68-year-old man had been referred to our department for a of a feeding gastrojejunostomy. Fluoroscopy was performed before needle puncture of the stomach, the transverse colon was seen to lie across the stomach, and an infracolonic approach was considered. The transverse colon could not be

From: John A. Spencer, MRCP, FRCR, FRCR Department of Radiology, John Oxford 0X3 9DU, England

session

up

or down

by

air

to better visualize it, diatrizoate Winthrop-Breon Laboratories, tered. To our surprise, a huge contrast

material

reaching

the

and

was

transverse

seen

colon

insufflation

into

the

stomach,

to overlap

the

This

stomach

had

obtained

after

rectal

administration

meglumine shows the sigmoid colon the transverse colon; direct puncture marks

Volume

the

costal

183

margin.

Number

#{149}

gastrojejunostomy: 1990; 12:340-341.

Vascular

and

for percuta-

Disease

E. W. L. Fletcher,

Radcliffe

after

MA,

Hospital

before

not been

ap-

The article by Naidich et al (1) in the January 1992 issue of Radiology casted doubt on the findings of Fellmeth et al (2), who observed rapid progression of arterial stenoses to occlusions after diagnostic angiography. We reported similar findings to those of Fellmeth et al in 1990 (3). Of 61 cases in which more than 24 hours had elapsed between diagnostic angiography and attempted femoral angioplasty, stenotic lesions had thrombosed in six. In three cases, superficial femoral artery stenoses progressed to complete occlusions, preventing angioplasty. In a fourth case, a short stenosis became a 10-cm-long occlusion, and angioplasty was deferred. The range of delay in the patients whose conditions deteriorated was 2-25 days (mean, 11.7

of diatrizoate

overlying the stomach and was impossible. The clamp

compared

with

a mean

of 14.6

days

for

the

cohort

over-

all. Our findings are thus more in keeping with those of Fellmeth et al than with Naidich et al. We were also surprised to find that the frequency and rapidity of deterioration after diagnostic angiography were vastly greater than those of peripheral vascular disease (4). We used diluted nonionic contrast material (150 ng/mL) with digital imaging for the diagnostic angiography procedures. The discrepancy between our findings and those of Naidich et al (1) may lie in differences in patient population. Naidich et al excluded patients with total occlusions and may thus have failed to study individuals with more severe disease. Because 3 years were required to accumulate less than 100 suitable patients in two centers, we would presume a much lower angioplasty rate in the institution of Naidich et al than in our own. Because our institution is the sole regional vascular surgery referral center for approximately 2.5 million people, perhaps we encounter a higher proportion of difficult cases. van Andel (5), who originally drew attention to this phenomenon, suggested that angiography was causative. He likened angiography to “a squall shaking a ripe apple from a tree which would have fallen itself in due time.” Galliano et al (6) reported even higher rates of deterioration than we did but were reluctant to ascribe blame to angiography. We found no statistical association between puncture site and deterioration, and no local complications occurred at diagnostic angiography in those

2

Modified catheter 1989; 173:276-278.

Editor:

days),

Radiograph

gastrostomy Radiology

and,

meglumine (Hypaque 30%; New York) was rectally adminisloop of sigmoid colon filled with (Figure).

Percutaneous feeding review of 252 patients.

of Peripheral Angiography

ration.

displaced

sig-

Gastrojejunostomy

From:

which

of the

both the sigmoid and transcontrast material should be

whose

conditions

deteriorated,

although

one

Radiolosv

patient

#{149} 583