Semiquantitative measurement of pulmonary hilar gallium-67 uptake using single photon emission computed tomography/computed tomography for the diagnosis of autoimmune pancreatitis.

Purpose: We ascertained the difference in the level of pulmonary hilar (PH) gallium-67 (Ga-67) uptake in autoimmune pancreatitis (AIP) patients between the active (before corticosteroid therapy) and remittent (after 4 weeks of corticosteroid therapy) phases using a semiquantitative measurement method based on single photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT).

Materials And Methods: Ga-67 planar scans and SPECT were performed in 11 AIP patients before and after 4 weeks of corticosteroid therapy. A region of interest (ROI) was drawn over the bilateral pulmonary hilum and the liver, and average counts of the pulmonary hilum and liver were calculated.

Usefulness of the automatic quantitative estimation tool for cerebral blood flow: clinical assessment of the application software tool AQCEL.

Objective: AQCEL enables automatic reconstruction of single-photon emission computed tomogram (SPECT) without image degradation and quantitative analysis of cerebral blood flow (CBF) after the input of simple parameters. We ascertained the usefulness and quality of images obtained by the application software AQCEL in clinical practice.

Methods: Twelve patients underwent brain perfusion SPECT using technetium-99m ethyl cysteinate dimer at rest and after acetazolamide (ACZ) loading.

[Development of the automated Patlak plot method and its verification in clinical examples].

The Patlak plot method is widely used in general clinical practice to calculate mean cerebral blood flow (mCBF) because it does not require arterial blood sampling and the procedure used is relatively simple. However, it has been pointed out that the calculation is affected by operator subjectivity and experience, and reproducibility is poor when the operator changes. The Patlak plot method consists of the following three procedures: (1) a region of interest (ROI) in the normal cerebral hemisphere is chosen to obtain the time-activity curve; (2) an ROI in the aortic arch is determined to obtain the time-activity curve; and (3) graphic analysis of the two time-activity curves is performed, and mCBF is determined from the slope of the graph.

[Development of an automatic analytical tool for quantitative cerebral blood flow measurement using 99mTc-ECD, and verification of clinical examples].

The following process conventionally has been followed to develop quantitative images of cerebral blood flow: (1) mean cerebral blood flow (mCBF) is calculated by the Patlak plot method; (2) a SPECT slice that includes the basal ganglia is selected; and (3) based on the value of mCBF calculated by the Patlak plot method, the SPECT slice is corrected by the Lassen method and developed into a SPECT image of quantitative regional cerebral blood flow. However, this process is complicated, and the values of rCBF have been reported to fluctuate because selection of the SPECT slice and the ROI setting are in the hands of the operator. We have developed new software that automates this analysis.