title: Semiconductor detectors allow low-dose-low-dose 1-day SPECT myocardial perfusion imaging.
abstract: Cadmium zinc telluride (CZT) detectors with linear counting rate response enable count subtraction in sequential scanning. We evaluated whether count subtraction eliminated the need for higher activity doses in the second part of the 1-d stress-rest myocardial perfusion imaging (MPI) protocol.
  
  
  METHODS
  For 50 patients (mean age ± SD, 66 ± 12 y) with visually abnormal (n = 42) or equivocal (n = 8) adenosine-stress MPI (320 MBq of (99m)Tc-tetrofosmin) on a CZT camera, rest MPI was performed with a low dose (320 MBq) and repeated after injection of an additional 640 MBq of (99m)Tc-tetrofosmin to achieve a standard 3-fold increased dose at rest (960 MBq), compared with stress (320 MBq). Low-dose rest myocardial perfusion images were reconstructed after subtracting the background activity of the preceding stress scan. Segmental percentage tracer uptake of the 2 rest myocardial perfusion images (320 vs. 960 MBq) was compared using intraclass correlation and Bland-Altman limits of agreement. Patient- and coronary territory-based clinical agreement was assessed.
  
  
  RESULTS
  The standard protocol revealed ischemia in 34 (68%) and a fixed defect in 8 (16%) patients, of whom 33 (97%) and 8 (100%) were correctly identified by low-dose MPI (clinical agreement, 98%). Segmental uptake correlated well between low- and standard-dose rest scans (r = 0.94, P < 0.001; Bland-Altman limits of agreement, -11 to +11%). Defect extent was 14.4% (low-dose) versus 13.1% (standard-dose) at rest (P = not statistically significant) and 26.6% at stress (P < 0.001 vs. rest scans).
  
  
  CONCLUSIONS
  These promising results suggest that accurate assessment of ischemic myocardial disease is feasible with a low-dose-low-dose 1-d SPECT MPI protocol using a CZT device.
authors.affiliation: Deparment of Radiology, Cardiac Imaging, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Rene
authors.initials: R
authors.lastname: Nkoulou
authors.forename: Aju P
authors.initials: AP
authors.lastname: Pazhenkottil
authors.forename: Silke M
authors.initials: SM
authors.lastname: Kuest
authors.forename: Jelena R
authors.initials: JR
authors.lastname: Ghadri
authors.forename: Mathias
authors.initials: M
authors.lastname: Wolfrum
authors.forename: Lars
authors.initials: L
authors.lastname: Husmann
authors.forename: Michael
authors.initials: M
authors.lastname: Fiechter
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
authors.forename: Bernhard A
authors.initials: BA
authors.lastname: Herzog
authors.forename: Pascal
authors.initials: P
authors.lastname: Koepfli
authors.forename: Cyrill
authors.initials: C
authors.lastname: Burger
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002104:Cadmium / Q000737:chemistry; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007511:Ischemia / Q000473:pathology; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009943:Organophosphorus Compounds / Q000737:chemistry; D015609:Organotechnetium Compounds / Q000737:chemistry; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals / Q000737:chemistry; D012666:Semiconductors; D013691:Tellurium / Q000737:chemistry; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D015032:Zinc / Q000737:chemistry
chemical_list: C474490:CdZnTe; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D002104:Cadmium; C078700:technetium tc-99m tetrofosmin; D015032:Zinc; D013691:Tellurium