Krypton-81m ventilation and technetium-99m macroaggregated albumin perfusion scintigraphy for detection of pulmonary embolism: the first experience in Taiwan.
BACKGROUND
This study was designed to assess whether the self-made (Institute of Nuclear Energy Research, Taiwan) krypton (Kr)-81m could be used as a ventilation agent to detect patients with suspected pulmonary embolism (PE). In addition, xenon (Xe)-133 ventilation scintigraphy was also performed for comparison.


METHODS
Forty patients with suspected PE were studied. Each patient received Kr-81m ventilation, Xe-133 ventilation and technetium (Tc)-99m macroaggregated albumin (MAA) perfusion studies on the same day. Images were judged using the criteria of the modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). For those with a high or intermediate probability of PE on lung scans and normal pulmonary function tests, anticoagulants were given and patients were monitored with Tc-99m MAA perfusion studies after treatment. The final diagnosis was based on chest radiography, pulmonary function tests and lung scans.


RESULTS
All 40 patients successfully underwent lung scans. Of these, 11 had PE. Ten of the 11 cases were detected using Kr-81m ventilation and Tc-99m MAA perfusion studies, resulting in a sensitivity of 91%. Seven of 11 cases were detected using Xe-133 ventilation and Tc-99m MAA perfusion studies, resulting in a sensitivity of 64%. Of the 11 patients with PE, four had PE alone; Kr-81m and Xe-133 results agreed in three patients, but Kr-81m detected PE in the remaining patient. Of the remaining seven patients who suffered from PE with obstructive airway disease, Kr-81m and Xe-133 agreed in four, but Kr-81m detected PE in another two patients and one case was missed by both studies.


CONCLUSIONS
Self-made Kr-81m was safe and effective for ventilation scintigraphy in humans. When Kr-81m was used for the detection of PE, it was particularly advantageous when PE occurred in small areas of the lungs or when the patient with PE had concurrent obstructive airway disease.
Cherng
S C
SC
Department of Nuclear Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC.
Yang
S P
SP
Wang
Y F
YF
Jen
T K
TK
Huang
W S
WS
Lo
A R
AR
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007727:Krypton Radioisotopes; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D012123:Pulmonary Ventilation; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes
D007727:Krypton Radioisotopes; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes