MEDIQ <MED> IN AMERICAN MEDICAL <AMI> UNIT BUY MEDIQ Inc said its MEDIQ Diagnostic Imaging Partners - I LP has signed a letter of intent to acquire substantially all the assets of American Medical International Inc's AMI Diagnostic Services Inc subsidiary for undisclosed terms. The company said AMI Diagnostic operates seven magnetic resonance and mutli-modality diagnostic imaging centers. MEDIQ Diagnostic is a limited partnership of which MEDIQ is general partner.