ABSTRACT
In 53 patients with cerebrovascular disease (CVD), regional cerebral blood flow (CBF) and blood volume (CBV) were imaged by SPECT within one session. Slice division (CBF: CBV) yielded distribution of regional cerebral perfusion reserve (CPR). Semiquantitative evaluation was obtained from manually set ROIs by interhemispherical ratios (for CBF, CBV and CPR), using 2 SD from a normal group (n = 10) as a threshold. Sensitivities were 59% for CBF, 94% for CBV and 83% for CPR. Combined sensitivity was 98%. Establishing three constellations for CBF, CBV and CPR, regionally normal CBFs but quantitatively increased CBVs (+69%) and decreased CPRs (-31%) were found in relatively early stages of CVD. Very advanced cases showed decreased CBFs (-65%), CBVs (-40%), CPRs (-49%) and a surrounding penumbra. In 87% (46/53 patients), such rheologically postulated constellations could be demonstrated. We conclude that combined CBF and CBV SPECT, assisted by CPR images, is a promising tool to detect CVD and to assess its individual regional severity.
Subject(s)
Blood Volume , Cerebrovascular Circulation , Cerebrovascular Disorders/diagnostic imaging , Erythrocytes , Organometallic Compounds , Oximes , Tomography, Emission-Computed , Aged , Cerebrovascular Disorders/physiopathology , Female , Humans , Male , Middle Aged , Perfusion , Technetium , Technetium Tc 99m ExametazimeABSTRACT
In 15 patients with coronary heart disease, 74 MBq 201Tl (A) and 240 MBq 99Tcm HMIBI (B) were injected during exercise on separate days and SPECT imaging was applied. In (B) a consecutive second injection was given with an identical dose 3 h later (at rest) and net rest distribution was obtained from a subtraction technique. From polar, target-like ROIs, data were computed to compare regional vitality, wash-out and wash-out corrected redistribution. Myocardial wash-out, in contrast to 201Tl, was found to be 20% for 99Tcm independent of the regional myocardial state. Since no considerable redistribution occurred, myocardial distribution of 99Tcm HMIBI remained rather constant for 3 h, resulting in a maximum myocardium to lung ration of about 5. After the second injection, redistribution revealed the same results as in the 201Tl targets. From regional exercise to rest ratios a 'perfusion reserve' was determined which was 2.1 in normal and 1.3 in myocardial areas with defects. Myocardial defect uptake and defect size were nearly identical, yielding agreement in 97% of the myocardial segments. We conclude that 99Tcm HMIBI is a most powerful myocardial imaging agent. The final routine protocol, however, is as yet not established.
Subject(s)
Coronary Disease/diagnostic imaging , Myocardium/metabolism , Nitriles/pharmacokinetics , Organometallic Compounds/pharmacokinetics , Technetium/pharmacokinetics , Thallium Radioisotopes/pharmacokinetics , Tomography, Emission-Computed , Humans , Physical Exertion , Technetium Tc 99m SestamibiABSTRACT
ROI-based polar maps (33 ROIs) were employed to evaluate quantitatively stress/rest myocardial 201Tl SPECT in 108 patients with angiographically proven coronary heart disease (CHD) in comparison with 30 controls. Sensitivity in detecting a CHD with stenoses of greater than 50% of luminal diameter was determined versus normal regional values (+/- 2.5 SD) employing vitality (VI) and wash-out corrected redistribution (RD). The method was evaluated referring to the severity of the disease, to the number of ROIs displaying changes [(a) 1 ROI, (b) greater than 2 ROIs], to validity of VI, RD or a combination thereof, and for specificity. Wash-out values were found to depend on degree of stress individually achieved and thus were not used as a threshold criterion. Sensitivity in supply areas with old myocardial infarctions was 95% (a) and 86% (b), resp. With no infarction, it was 96% (a) and 79% (b), resp. VI in stenosis greater than 75% was more sensitive than RD. However, combined evaluation of VI and RD yielded sensitivities from 91-100% (a) and 77-94% (b), resp. for different main supply areas. In stenosis less than 50% with normal VI, RD was positive in 18-31%. Specificity turned out to be 91% (a) and 97% (b), resp. We conclude that the method presented is reliable to quantify numerically 201Tl kinetics in myocardial SPECT, aimed at detecting and describing CHD.
Subject(s)
Coronary Disease/diagnostic imaging , Heart/diagnostic imaging , Thallium Radioisotopes , Tomography, Emission-Computed , Adult , Exercise Test , Female , Humans , Male , Methods , Middle Aged , Reference Values , Sensitivity and SpecificityABSTRACT
A semiautomated method for three-dimensional quantification of stress/rest 201Tl myocardial SPECT of the left ventricle (LV) is introduced. A total of 33 ringsegment-shaped regions of interest (ROIs) are distributed over 6 oblique (short axis cuts) double-slices (thickness 1.3 cm) from LV apex to base, commencing with 1 ROI for the apex up to 8 ROIs for the base (1-4-4-8-8-8). Within the last two double slices an additional adjacent ROI is automatically placed in the upper right quadrant to observe lung TI-uptake. Correspondence of slices for exercise and rest is achieved by adjusting the long axis outlines rebuilt from summed profiles of 15 oblique slices of each examination. Calculated numeric arrays of the extracted parameters (vitality, washout and redistribution) are displayed in a target-like two-dimensional polar fashion.
