title: Prone-position acquisition of myocardial (123)I-metaiodobenzylguanidine (MIBG) SPECT reveals regional uptake similar to that found using (11)C-hydroxyephedrine PET/CT.
abstract: OBJECTIVE
  (123)I-metaiodobenzylguanidine (MIBG) has been used to estimate cardiac sympathetic nervous innervation. Heterogeneous MIBG distribution is mainly associated with high physiological MIBG uptakes in the liver. We postulate that prone position acquisition might be especially effective for MIBG, providing for separation from high liver uptake similar to that provided by perfusion single-photon emission computed tomography (SPECT). We investigated whether prone-position acquisition improved MIBG image quality by comparing our results to those acquired using supine MIBG and high-quality (11)C-hydroxyephedrine (HED) positron emission tomography/computed tomography PET/CT.
  
  
  METHODS
  Ten male volunteers (body mass index (BMI) 22.7 ± 3.4) underwent prone and supine MIBG and HED PET. Relative regional tracer uptake was estimated in early MIBG and HED. Acquired images were divided into 17 segments and were grouped into 4 regions: anterior, inferior, septum, and lateral. For each patient, the inferior/anterior ratio was calculated.
  
  
  RESULTS
  The quality of images acquired using prone MIBG was better than that using supine MIBG (p < 0.05). Inferior and septum relative MIBG uptake was reduced in comparison with anterior or lateral MIBG uptake in the supine position (inferior vs. anterior: 69.0 ± 5.6 vs. 82.3 ± 4.6 %, p < 0.01; septum vs. lateral: 66.2 ± 5.1 vs. 81.9 ± 5.4 %, p < 0.01). Prone MIBG showed a significantly higher inferior/anterior uptake ratio in comparison with supine MIBG (n = 24, seg: 92.2 ± 7.2 vs. 83.6 ± 5.7 %, p < 0.05). However, intergroup differences in uptake ratio were demonstrated among prone and supine MIBG and HED. HED PET/CT still showed a higher uptake ratio in comparison with prone MIBG SPECT (103.9 ± 8.0 vs. 92.2 ± 7.2 %, p < 0.05).
  
  
  CONCLUSIONS
  Even in normal male subjects, standard supine MIBG imaging showed reduced inferior and septum uptake. Uptake with prone MIBG imaging showed a significant improvement over that with supine imaging and was closer to uptake for HED PET/CT. This improvement may be the result of preventing intense uptake by the liver. Prone data acquisition may be a viable alternative in evaluating regional abnormalities using MIBG SPECT in men.
authors.affiliation: Department of Molecular Imaging, Hokkaido University Graduate School of Medicine, Kita15 Nishi7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan, kyoshi@med.hokudai.ac.jp.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Yoshinaga
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Tomiyama
authors.forename: Osamu
authors.initials: O
authors.lastname: Manabe
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kasai
authors.forename: Chietsugu
authors.initials: C
authors.lastname: Katoh
authors.forename: Kenichi
authors.initials: K
authors.lastname: Magota
authors.forename: Eriko
authors.initials: E
authors.lastname: Suzuki
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Nishijima
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kuge
authors.forename: Yoichi M
authors.initials: YM
authors.lastname: Ito
authors.forename: Nagara
authors.initials: N
authors.lastname: Tamaki
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D001835:Body Weight; D002247:Carbon Isotopes; D002395:Catecholamines / Q000097:blood; D004809:Ephedrine; D064368:Healthy Volunteers; D006321:Heart / Q000000981:diagnostic imaging*; D006439:Hemodynamics; D006801:Humans; D007457:Iodine Radioisotopes; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D009206:Myocardium / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D016684:Prone Position; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D002247:Carbon Isotopes; D002395:Catecholamines; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D004809:Ephedrine