A patch which adds support for TIFF predictor 2 within FlateDecode. Currently the patch only supports 8 bits per component. Handling 4 bits per component could be implemented but I have no test document.
The patch can be tested against http://pediatrics.aappublications.org/cgi/reprint/125/1/1
the title graphic (Im0 at page 1) uses predictor type 2.