TY - JOUR T1 - 2-Year Natural Decline of Cardiac Sympathetic Innervation in Idiopathic Parkinson Disease Studied with <sup>11</sup>C-Hydroxyephedrine PET JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 326 LP - 331 DO - 10.2967/jnumed.116.176891 VL - 58 IS - 2 AU - Ka Kit Wong AU - David M. Raffel AU - Nicolaas I. Bohnen AU - Gulcin Altinok AU - Sid Gilman AU - Kirk A. Frey Y1 - 2017/02/01 UR - http://jnm.snmjournals.org/content/58/2/326.abstract N2 - The objective of this study was to detect regional patterns of cardiac sympathetic denervation in idiopathic Parkinson disease (IPD) using 11C-hydroxyephedrine (11C-HED) PET and determine the denervation rate over 2 y. Methods: We obtained 62 cardiac 11C-HED PET scans in 39 patients (30 men and 9 women; mean age ± SD, 61.9 ± 5.9 y), including 23 patients with follow-up scans at 2 y. We derived 11C-HED retention indices (RIs; mL of blood/min/mL of tissue) reflecting nerve density and integrity for 480 left ventricular (LV) sectors. We compared IPD patients with 33 healthy controls using z score analysis; RI values ≤ 2.5 SDs were considered abnormal. We expressed global and regional LV denervation as the percentage extent of z score severity and severity-extent product (SEP) on 9-segment bullseye maps and decline in cardiac sympathetic innervation as the 2-y difference in SEP (diff-SEP). Results: Baseline 11C-HED PET in the 39 IPD patients revealed an RI mean of 0.052 ± 0.022 mL of blood/min/mL of tissue. In comparison with data from normal controls, 12 patients had normal 11C-HED PET, 5 showed mild denervation (percentage extent &lt; 30%), and 22 had moderate to severe denervation (percentage extent &gt; 30%, z score ≤ 2.5 SD). In the 23 paired PET scans, worsening cardiac denervation (global diff-SEP &gt; 9) occurred in 14 of 23 (60.9%) patients over 2 y, including percentage LV abnormality (59% increasing to 66%), z-severity (–2.4 down to –2.5), and SEP (–195 to –227) (P = 0.0062). We found a mean annual decline of 4.6% ± 5.6 (maximum, 13%) in 11C-HED retention from a baseline global RI mean of 0.0481 ± 0.0218 to 0.0432 ± 0.0220 (P = 0.0009). At baseline, 5 patients with normal uptake had no interval change; 3 with mild denervation developed interval decline in lateral and inferior segments (diff-SEP –82 to –99) compared with anterior and septal segments (–65 to –79), whereas the reverse pattern occurred in 15 patients with severe baseline denervation. Conclusion: Progressive decline in cardiac sympathetic neural integrity in IPD patients occurs at a modest rate over 2 y on 11C-HED scans with marked heterogeneity and a regional pattern of involvement and decline. ER -