Figure 9a. Pyelonephritis in a young woman with hypercoagulable state, pulmonary embolism, and right flank pain during the second trimester. Renal vein thrombosis was suspected at clinical evaluation. (a) Axial fat-suppressed T2-weighted gradient- and spin-echo image shows an enlarged, edematous right kidney with striated signal intensity (arrow). The atrophic left kidney (arrowhead) resulted from a prior ischemic event. (b) Axial targeted maximum intensity projection image from time-of-flight MR angiography shows a patent renal vein (arrow). A urine culture yielded Escherichia coli.