ABSTRACT
An accurate identification of cerebral structures is necessary to perform quantification of single photon emission computed tomography (SPECT). We have developed an anatomical localization system that accounts for individual brain shapes and sizes by using the Talairach proportional grid system. The locations of the commissural lines, which define the stereotactic coordinate system, are calculated from the external landmarks provided by the canthomeatal line. This is validated on MRI images. When applied to SPECT data, the use of a neuroanatomical atlas data along with the automaticity of the processing guarantees a high degree of objectivity and inter-observer reproducibility.
Subject(s)
Brain/anatomy & histology , Brain/diagnostic imaging , Image Processing, Computer-Assisted , Stereotaxic Techniques , Tomography, Emission-Computed, Single-Photon , Anatomy, Artistic , Database Management Systems , Humans , Magnetic Resonance Imaging , Medical Illustration , Observer Variation , Organotechnetium Compounds , Oximes , Reproducibility of Results , Technetium Tc 99m Exametazime , Temporal Lobe/anatomy & histology , Temporal Lobe/diagnostic imagingABSTRACT
We report on a patient in whom we observed an unusually important upward creep of the heart on postexercise 201TI tomographic acquisition. When uncorrected, this led to reconstruction of grossly abnormal tomograms, which were normal after correction of upward creep of the heart. This phenomenon may be related to the patient's history of chronic obstructive pulmonary disease. Special attention should be given to upward creep artifact in such pulmonary diseases.
Subject(s)
Artifacts , Coronary Disease/diagnostic imaging , Heart/diagnostic imaging , Lung Diseases, Obstructive/physiopathology , Tomography, Emission-Computed, Single-Photon , Aged , Exercise/physiology , Exercise Test , Humans , Image Processing, Computer-Assisted , Male , Respiration/physiology , Thallium RadioisotopesABSTRACT
This study evaluated the correlations between left ventricular (LV) diastolic parameters assessed by equilibrium radionuclide angiography (ERNA) and heart rate (HR) through right ventricular pacing. Twelve patients with a permanent right ventricular apex pace-maker were included. Serial ERNA studies were performed under 6 sets of pacing cycle length (heart rate = 52, 62, 72, 82, 92, 104 beats/min) for each patient. The left ventricular ejection fraction was 49.9% +/- 3.1% under pacing HR of 52 bpm and 43.8% +/- 3.1% under pacing HR of 104 bpm. The peak filling rate (PFR) increased very significantly with HR (r = 0.98, P less than 0.001). When the relative changes of end-diastolic volume were taken into account, the correlation between PFR and HR remained significant (r = 0.94, P less than 0.001). The absolute time to PFR (TPFR) did not significantly change with HR, but the ratio of TPFR to cycle length strongly correlated with HR. Our study clearly demonstrates that the PFR assessed by ERNA increases and the TPFR occupies an increasing proportion of the cycle length as HR increases. Therefore, LV diastolic parameters should be normalized for HR in clinical applications. In particular, HR changes should be considered when LV diastolic parameters are used for the assessment of therapeutic interventions.