Læknablaðið : fylgirit - 01.06.1982, Page 24

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COMPARISON OF TECHNETIUM PYROPHOSPHATE SCANNING WITH CON-
VEíniŒIAL ÐIAGNOSIS OF ACUTE MYOCARDIAL INFARCTION.
P.Jonssœ, H.Sigurdsson, H.Valdimarsson, E.Bjorgvinsson,
A.Brekkan, T.Hardarson, Depairtments of Medicine & Radiology,
Reykjavik City Hospital, Reykjavik, Iceland.
The purpose of this study was to examine the vali e and
limitations of technetium pyrophosphate isotope scanning in
the diagnosis of acute nyocardial infarction (AMI) in a
general nedical department. AMI was diagnosed with two of the
following: Classical chest pain, ECG, myocardial infarction
pattem according to WHO criteria or typical CB-MK isoenzyme
elevation.
Fifty five patients, 41 males, 14 feirales, with a mean
age of 63.0 years (32-87) fulfilled the criteria for AMI, 34
were transmural, 18 subendocardial, 3 of uncertain location.
For conparison we scanned 11 healthy controls and 14 with
heart diseases other than AMI or unœrtain heart diseases,
eight of them with angina pectoris. Ihe scans were evaluated
blindly and independently by two radiologists for isotope
activity, location and size within th^ heart. These results
were conapared with AMI diagnosis, with ECG for infarct
location, and with integrated MB-CK activity for infarct size.
We found the sensitivity of early (<5 days) technetium
pyrophosphate scans in diagnosing AMI 75% (26/35), and the
overall specificity 91% (21/23). The predictive value of
positive scans was 95% (39/41) and the predictive value of
negative scans 57% (21/37). Ihe concordance between anterior
locations of infarct by ECG and scans was 81% (17/21) and for
inferior location 55% (6/11). No concordance was found between
infarct size by integrated MB-CK activity and estimated size
by scans.
We conclude that technetium pyrophosphate scanning may
be of value in uncertain cases of suspected AMI but should
not be routinely applied for the diagnosis.