Faculty Bibliography

The accuracy and precision of an automated graph-cuts (GC) segmentation technique for dynamic contrast-enhanced (DCE) 3D MR renography (MRR) was analyzed using 18 simulated and 22 clinical datasets. For clinical data, the error was 7.2 +/- 6.1 cm(3) for the cortex and 6.5 +/- 4.6 cm(3) for the medulla. The precision of segmentation was 7.1 +/- 4.2 cm(3) for the cortex and 7.2 +/- 2.4 cm(3) for the medulla. Compartmental modeling of kidney function in 22 kidneys yielded a renal plasma flow (RPF) error of 7.5% +/- 4.5% and single-kidney GFR error of 13.5% +/- 8.8%. The precision was 9.7% +/- 6.4% for RPF and 14.8% +/- 11.9% for GFR. It took 21 min to segment one kidney using GC, compared to 2.5 hr for manual segmentation. The accuracy and precision in RPF and GFR appear acceptable for clinical use. With expedited image processing, DCE 3D MRR has the potential to expand our knowledge of renal function in individual kidneys and to help diagnose renal insufficiency in a safe and noninvasive manner

A 44-year-old man with a left perinatal stroke and recurrent refractory epilepsy underwent functional MRI (fMRI) for motor and language mapping to determine if further epilepsy surgery could be performed without loss of language. Language was activated excessively in the right hemisphere, with only small areas of left hemisphere activation. This suggests bilateral language dominance acquired secondary to the perinatal stroke with the right hemisphere activation resulting from neonatal neuronal reorganization. Functional data were overlaid onto 3D diffusion tensor tractography, providing a unique image of the right hemisphere language recruitment

Teriparatide, the active fragment of human parathyroid hormone (hPTH 1-34), is an anabolic agent for the treatment of osteoporosis. Important questions remain regarding management strategy beyond the recommended 18- to 24-month course of teriparatide treatment. We followed 21 men for up to 2 years after discontinuing teriparatide. Twelve men (57%) chose treatment with bisphosphonate immediately after teriparatide withdrawal, while 9 (43%) opted for no pharmacologic agent. At the end of 1 year lumbar spine bone density increased an additional 5.1+/-1.0% in the bisphosphonate group, while it declined by 3.7+/-1.7% in those on no medication (P<0.002). In six men who delayed initiation of bisphosphonate until 1 year after teriparatide withdrawal, their subsequent gains in the second year, 2.6+/-1.7%, still placed them below the peak gains they achieved on teriparatide. In contrast, the 12 men who began bisphosphonates immediately and continued treatment for the entire 2-year post-PTH period had continued gains at the lumbar spine, 8.9+/-1.5% above their post-PTH values (P=0.002). For the 4-year period, including 2 years of teriparatide and 2 years of bisphosphonate, the total gains at the lumbar spine were 23.6+/-2.9%. Men, who received bisphosphonate in only the 2nd year post-teriparatide, had cumulative gains of 11.1+/-3.4%. Three men who did not receive any bisphosphonate at any time during the post-PTH period had cumulative gains of only 5.5+/-3.7%. These findings suggest that the use of bisphosphonates following teriparatide is an important component of any strategy utilizing this anabolic drug for osteoporosis in men. The immediate use of bisphosphonates after teriparatide withdrawal may help to optimize gains in bone density at the lumbar spine.