hepanin els.

pending

There

the

were

no

attainment

cedune. No pnedisposing ered; the patient remains Widlus

et al have

or to treatment bolysis,

of therapeutic

complications

during

cause of the symptoms symptom-free.

shown

that

the

is an important

but

they

infer

wanfanin

that

the

was

pro-

of symptoms should

throm-

be

for

DM,

upper

Venbrux

AC,

extremity

Benenati

arterial

JF, et al.

occlusions.

ms)

20

consid-

ered even with a long-standing history. We entirely agree with this suggestion and confirm that excellent results can be obtained in the patient with a delayed presentation. Reference 1. Widlus

423

(Ti

pni-

for complete

treatment

S low Ti pIxels 30

discov26

duration

indicator such

1ev-

or following

Fibrinolytic

Radiology

\

\

10

:

therapy

1990;

16

175:393-

399.

20

30

after

days U Marrow Transplantation

Repopulation

After

Bone

Marrow

Alterations in lumbar

From: Stephen R. Smith, MRCP, Neil T. Edwards, FRCP Magnetic Resonance Research

P0 Box 147, Liverpool

Roberts,

PhD,

Centre,

and

Richard

University

L69 3BX, United

H.

April

1990

interesting

and

issue

of Radiology,

important

data

nance (MR) characteristics plantation. We have also niques dergoing for

to study lumbar autobogous

refractory

bowed

or

up

nine

Stevens concerning

this

relapsed

bone marrow transplantation

Hodgkin

patients

et al (1) present the magnetic reso-

of vertebral marrow after transused quantitative MR imaging tech-

vertebral bone marrow serially

disease to the

time

in

patients (ABMT)

(2) and

have

of recovery

un-

fobof sta-

ble, normal peripheral blood counts. In our initial study, a decrease in mean lumbar vertebral marrow Ti relaxation time was seen after a chemotherapy-based conditioning regimen. Ti then recovered as hematopoietic engnaftment occurred, sometimes

to bevels

higher

than

those

before

transplantation.

Changes in Tl, measured with use of region of interest (ROI) cursors, mirrored the recovery of peripheral blood neutrophib and platelet counts and presumably reflect alterations in manrow cellularity (2). However, the zone pattern reported by Stevens et al was not observed in any of our patients with use of imaging protocols (repetition time msec/echo time msec, 500/25,

the

relaxation

time

measurements

be viewed with caution due to the use of a method and multisection imaging techrelaxation time measurements made with

use of ROI cursors in heterogeneous

are associated with tissues such as bone

we

use

problems, marrow

multiple

point,

pixel-by-pixel

image

analysis

techniques

with

particularly (3). For these Ti

mapping

in

to monitor

tionship

protocol

provides

reproducible

relaxation

time

data

(4).

in color

of thresholded

means ban

of ABMT. vertebrae

In

these

studies

are

the

The

transplantation

to factors ease prior therapy tioning transplant

and radiation regimen used, was placed,

178

Number

#{149}

2

for

body

can

of area of marrow in a treatment by

all

zones

in

Ti

pixels

consistent

of the

the

of marrow by

the

bum-

zonal

differences

pattern

relaxation

image

analysis

of measuring heterogeneous be monitored

in

regeneration

different

of results

made. Pixel-by-pixel with

reasons

these

after

workers

may

marrow be

related

and the state of previous

of dischemo-

received, the particular condian autobogous or allogeneic presence of graft-versus-host

of all these

comparisons

details

from

time

techniques

is necessary

different

studies are

if mean-

centers

used

are

to be

in conjunction

superior

to ROI

methods

relaxation time data. They enable potentially changes in tissues or tumors after treatment quantitatively.

to

References

I.

Volume

images.

vertebral

in support

therapy whether and the

A knowledge

ingfub

erwood

for the below

low

such as the underlying disease to transplantation, the intensity

JPR,

is used as a Ti threshold distribution of Ti pixels

in

evidence

observed

Jenkins

value spatial

the

to therapy, increase

pattern

3.

This the

an

possible

MR

Smith SR. Williams magnetic resonance

subjects. data, and

within

response

showed

2.

control patient

gray-scale

of engraftment proposed by Stevens et ab (ie, persistent bow Ti pixels in the central area of the vertebral bodies corresponding to zone 4, and a peripheral area of high Ti pixels corresponding to zone 1).

gonithms (Struers

isolate only those pixels that refer to the lumbar vertebral bone marrow. The Ti data are displayed in histogram form, and the Ti value of the 5% probability limit is calculated (423 msec) from the pooled Ti histogram data of 18 age-matched

original

with myeboabbative chemotherapy, followed by a decrease in the number of bow Ti pixels as engraftment occurred. Twelve studies have been performed 40-90 days after ABMT; none of

1.

analysis system then used to

pixels

showed

The boundaries of the lumbar vertebral bodies are identified semiautomatically (less than 5% operator interaction) from proton density MR images with use of line detection alavailable on a Context Vision image Vision AB, Sweden). These masks are

on

then be quantified objectively. The Figure shows the alterations in percentage the bow Ti pixels in zones 1-4 of the vertebral patient with Hodgkin disease before and after

disease.

changes in the lumbar vertebral marrow after ABMT. Ti maps are computed with use of a SUN 3/160 workstation (Sun Microsystems, Mountain View, Cabif) from six spin-echo images acquired with repetition times varying from 2,400 to 250 msec of a single midline sagittal section of the lumbar vertebrae. A 10-mm section thickness is used, and pixel nesolution is 1.88 X 1.88 mm. All MR imaging data were acquired with a 1.5-T Signa system (GE Medical Systems, Milwaukee). The

is displayed

results?

they present must two-point data fit niques. In addition,

conjunction

limit

What

et ab state,

423 msec) ABMT for cortex of zone 4, X zone

The area of these thresholded pixels is then calculated. In particular, with use of morphologic image analysis techniques, the masks are successively shrunk in bands of 5 pixels deep, enabling four separate zones of marrow to be isolated. These range from a peripheral area (zone 1) adjacent to the cortex of the vertebral body to a central area (zone 4). The spatial nela-

250/25).

As Stevens

reasons,

in percentage of area of low Ti pixels (Ti vertebral marrow of patient who underwent refractory Hodgkin disease. Zone i was adjacent to the the vertebral body, moving in through zones 2 and 3 to which occupied the central area of the vertebral bodies. 1, = zone 2, * zone 3, 0 zone 4.

of Liverpool

Kingdom

Editor:

In the

treatment

Stevens 5K, Moore ter transplantation: diology

1990;

plantation

4.

SC, Amylon MR imaging

Repopulation pathologic

of marrow correlation.

afRa-

175:213-218.

CE, Edwards RHT, Davies JM. Quantitative imaging in autologous bone marrow transHodgkin’s disease. Br J Cancer 1989; 60:961-965.

for

Stehling

M,

Quantitative

bodies:

a T1 and

Smith

SR. Williams characterization

ogy

172:805-810.

Sivewright

C,

magnetic

T2 study.

disorders:

1989;

MD. with

Magn

CE, Davies with

Hickey

resonance Reson

JM,

Imaging

Edwards

quantitative

DS,

imaging 1989;

RHT. MR

Hillier

VF,

Ish-

of vertebral 7:17-23.

Bone imaging.

Radiology

marrow Radiol-

581

#{149}