Can Pantoprazole be Used for Premedication in Meckel Scintigraphy?

Objectives: Meckel scintigraphy is used to diagnose Meckel's diverticulum. Previously, premedication with ranitidine was the most frequently used method to increase the accuracy of scintigraphy. However, ranitidine can no longer be used because it is banned by the Food and Drug Administration. The aim of this study was to investigate the usability of pantoprazole as a premedication instead of ranitidine in Meckel scintigraphy. Methods: Twelve New Zealand rabbits were used in this experimental study. Rabbits were divided into two groups: pantoprazole and control. Six rabbits were premedicated with pantoprazole for three days. Meckel scintigraphy was performed on all rabbits. Counts were made and compared by drawing regions of interest from the stomach walls. Results: According to the findings of this experimental study, pantoprazole significantly increased Tc-99m-pertechnetate uptake in the stomach of rabbits on both visual and quantitative evaluation. Conclusion: Pantoprazole increases the gastric wall uptake of Tc-99m-pertechnetate in rabbits and is a potential drug for premedication in Meckel scintigraphy.

Confirmation of PSMA expression measured on [68Ga]Ga-PSMA PET/CT by immunohistochemistry in prostate adenocarcinoma.

BACKGROUND: Our aim is to determine the accuracy of [68Ga]Ga-PSMA PET/CT in showing PSMA expression in primary prostate cancer and to investigate the relationship between SUVmax and immunohistochemical PSMA expression, Gleason score, and PSA value. MATERIAL AND METHODS: We retrospectively analyzed 66 male patients who were diagnosed with primary prostate adenocarcinoma, underwent pre-treatment [68Ga]Ga-PSMA PET/CT examination for staging, and performed radical prostatectomy between March 2018-August 2020. Immunohistochemical staining was applied to the radical prostatectomy specimens of all patients to detect PSMA expression. The results were evaluated as an immunoreactive score (IRS) and a modified IRS was obtained. Gleason score groups and prostate-specific antigen (PSA) serum values of the patients were obtained from the patient files. RESULTS: The high SUVmax of primary prostate tumors was significantly correlated with a high modified IRS score (score 2; 3), high PSA value, high Gleason score, and metastasis. In correlation analysis, a positive correlation was found between SUVmax and PSA value and modified IRS score (r = 0.69, p = 0.001; r = 0.39, p = 0.001). In addition, there was a statistically significant weak correlation between PSA serum concentration and modified IRS scores (r = 0.267; p = 0.03). In regression analysis, the percentage of positive cells had a statistically significant and increasing effect on SUVmax (p = 0.031; std beta = 0.268; 95% CI = 0.231-4.596). CONCLUSIONS: In prostate adenocarcinoma, SUVmax of the primary tumor in [68Ga]Ga-PSMA PET/CT correlates with immunohistochemical PSMA expression. In addition, high SUVmax is associated with markers of poor prognoses, such as high PSMA expression, PSA value, and Gleason score.

Role of F-18 FDG PET/CT in Predicting Response to Neoadjuvant Chemotherapy in Invasive Ductal Breast Cancer.

Objective: The role of baseline and post-treatment standardized uptake value (SUVmax) values in predicting pathological response in patients with breast cancer after neoadjuvant chemotherapy (NAC). Materials and Methods: Thirty patients with invasive ductal breast cancer were included in this retrospective study. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) examinations were performed before and after NAC. Pretreatment SUVmax (SUVmax I), post-treatment SUVmax (SUVmax II) and ΔSUVmax values of primary breast cancer were obtained. Breast tumor pathology preparations were examined for the evaluation of tumor response according to the Miller and Payne classification. Patients were grouped as responding to treatment (pCR) and unresponsive to treatment (nonpCR). In all analyses, p<0.05 was considered statistically significant. Results: The mean age of the 30 patients included in the study was 51.2±11.98 years. In the study-defined grouping, 13 patients (43.3%) were nonresponders and 17 patients (56.7%) were responders. ΔSUVmax was significantly greater in the responders group compared to the nonresponders group, while SUVmax II was lower (p = 0.001 and p = 0.004, respectively). There was no significant difference between the responders and nonresponders in terms of age, tumor diameter, and SUVmax I values. Multivariate logistic regression analysis showed ΔSUVmax to be the only independent predictive factor for pCR. Conclusion: F-18 FDG PET/CT was an effective method in evaluating the treatment response after NAC in breast cancer, and ΔSUVmax and post-treatment SUVmax can be used to predict the response of the primary tumor to treatment.

Relationships of 18F-FDG uptake by primary tumors with prognostic factors and molecular subtype in ductal breast cancer.

OBJECTIVES: In this study, we aimed to investigate the correlation between SUVmax of primary tumor and prognostic factors/molecular subtype in ductal breast cancer patients. MATERIALS AND METHODS: We retrospectively reviewed 150 female patients with pathologically proven invasive ductal breast cancer from January 2015 to October 2019 who underwent 18F-FDG PET/CT for initial staging. Histopathological prognostic features of the primary tumor (histological grade, hormone receptor status, Ki-67 index, vb.) were obtained from the tru-cut biopsy report. In 18F-FDG PET/CT studies, the maximum standardized uptake value (SUVmax) of the primary breast tumor was calculated and compared with the presence of axillary lymphadenopathy and/or distant metastases, histopathological prognostic factors and molecular subtype. RESULTS: The high SUVmax of primary breast tumors is significantly correlated with the clinicopathological factors: high tumor size, high histologic grade, high Ki-67 index, axillary lymph node positivity and distant metastasis. SUVmax value was significantly higher in patients with basal subtype than patients with Luminal A subtype (8,14 ±â€¯3,71 and 4,64 ±â€¯2,45, p = 0,002). Correlation analysis revealed a low correlation between Ki-67 index and SUVmax (r = 0,276, p = 0,001) and moderate correlation between tumor size and SUVmax (r = 0,470, p = 0,001). In multivariate linear regression analysis, Ki-67 index and tumor size had a statistically significant effect on SUVmax values. As these parameters increase, it is seen that it increases SUVmax values (p = 0,004, Std Beta: 0,228, 95% CI:0,010-0,055 and p = 0,001, Std Beta:0,374, 95% CI:0,55-0,136, respectively). CONCLUSION: High SUVmax value is associated with factors suggesting poor prognosis. Pretreatment 18F-FDG PET/CT can be used as a tool to predict prognosis in breast cancer.

Physiological Animal Imaging with 68Ga-Citrate.

BACKGROUND: Gallium-68 is an ideal research and hospital-based PET radioisotope. The uptake mechanism of Gallium citrate is a combination of specific and non-specific processes, for example, vasodilatation, increased vascular permeability, plasma transferrin binding and lactoferrin and siderophores. OBJECTIVE: In this study, by applying the 68Ge/68Ga generator product, a simple technique for the synthesis and quality control of 68Ga-citrate was introduced and was followed by preliminary animal studies. METHODS: The synthesis of 68Ga-citrate was performed with a cationic method using the Scintomics automated synthesis system (Scintomics GmbH GRP module 4V). Since the standard procedure for quality control (QC) was not available, the definition of chemical and radiochemical purity of 68Ga-citrate was carried out according to the ICH Q2(R1) guideline. The standard QC tests were analysed with Scintomics 8100 radio-HPLC system equipped with a radioactivity detector. In this study, a New Zealand rabbit weighing 2520 g was used for PET/CT images. RESULTS: 68Ga-citrate synthesis was performed by a cationic method without using organic solvents. The labelling efficiency was found to be >98%. The HPLC method used to assess the radiochemical purity of 68Ga -citrate was validated as rapid, accurate and reproducible enough to apply it to patients safely. The physiological distribution of 68Ga-citrate was investigated in a healthy rabbit. The blood pool, liver, spleen, kidneys and growth plates were the most common sites of 68Ga-citrate involvement.

High-Efficiency Cationic Labeling Algorithm of Macroaggregated Albumin with 68 Gallium / 대한핵의학회잡지

Purpose@#The generator product radionuclide gallium-68( 68 Ga) is widely used for PET/CT imaging agents and the 68 Ga-labeled MAA is an attractive alternative to 99m Tc-labeled MAA. Using a commercially available MAA labeling kit for 99m Tc, we presented a reliable synthesis protocol with a highly efficient, organic solvent-free cationic method in GMP conditions in the Scintomics automated synthesis unit. @*Methods@#The labeling process was performed by incubating for 7 min at 90 ° C in the borax vial containing the generator product68 GaCl 3 MAA-HEPES eluted from the PSH + cartridge with 1.5 mL 5 molar NaCl. Quality control of the final product content was examined, and radiopharmaceutical production was carried out in accordance with GMP guidelines. @*Results@#68 Ga eluted from the generator was obtained in more than 99% radiochemical purity and efficiency. In this case, the labeling efficiency was found to be >99%. When the results of SEM-EDX analysis in the final product were examined, it was determined that most of toxic metals were no appreciable in the product content. @*Conclusions@#The radiochemical and chemical purity of the final product allows direct use without purification steps to remove “free 68 Ga” or other toxic compounds.

68Ga-citrate positron emission tomography/computed tomography findings in an experimental model of acute appendicitis in rabbits.

OBJECTIVE: Acute appendicitis (AA) is a common urgent surgical situation of the gastrointestinal tract. Gallium-68 (68Ga)-citrate has been recently investigated as a radiopharmaceutical for infection and inflammation imaging. Aim of the study was to determine the effectiveness of 68Ga-citrate positron emission tomography/computed tomography (PET/CT) imaging in rabbits with experimentally induced AA. MATERIALS AND METHODS: In the AA group (n=6), the appendices of the rabbits were surgically ligated. The sham group (n=6) was used as control. Gallium-68-citrate was synthesized. All rabbits were imaged using 68Ga-citrate PET/CT at 36th following the establishment of experimental models, and at 36th h, all rabbits were appendectomised. Appendices were examined histopathologically. Blood samples were drawn from all rabbits at the beginning and end of the experimental process. Interleukin-6 (IL-6) and procalcitonin (Pct) levels were measured. Acute appendicitis was confirmed histopathologically and biochemically. RESULTS: Gallium-68-citrate PET/CT showed acute appendicitis in all rabbits. The sensitivity, specificity and accuracy of 68Ga-citrate PET/CT in AA were 100%, 83.3% and 91.7%, respectively. CONCLUSION: Acute appendicitis is accurately imaged in an experimental rabbit model by using 68Ga-citrate with PET/CT.

Comparison of 68Ga-PSMA-I/T PET-CT and Multiparametric MRI for Locoregional Staging of Prostate Cancer Patients: A Pilot Study.

BACKGROUND/AIM: The objective of this work was to assess the value of 68Ga-DOTAGA-(3-iodo-y)fk(Sub-KuE) positron emission tomography (68Ga-PSMA-I/T PET-CT) and multiparametric magnetic resonance imaging (mp-MRI) for preoperative staging in prostate cancer (PCa) patients who underwent radical prostatectomy (RP) by validating with postoperative histopathology data. MATERIALS AND METHODS: We prospectively investigated 30 consecutive PCa patients who had both mp-MRI and 68Ga-PSMA-I/T PET-CT before laparoscopic RP. The seminal vesicle invasion (SVI), lymph node metastasis (LNM), bladder neck invasion (BNI), and extracapsular extension (ECE) were investigated separately. The diagnostic performances of mp-MRI and 68Ga-PSMA-I/T PET-CT were assessed using histopathological results. RESULTS: Both mp-MRI and 68Ga-PSMA-I/T PET-CT were not statistically significant in the evaluation of SVI, BNI, and ECE preoperatively but had statistically significant results in the assessment of LNM. mp-MRI had higher overall sensitivity for ECE, overall specificity for SVI, ECE, and BNI, and positive predictive value for ECE, SVI, BNI. 68Ga-PSMA-I/T PET-CT had higher overall sensitivity for BNI, and negative predictive value for BNI and LNM. CONCLUSION: mp-MRI has superior specificity, sensitivity, and accuracy for assessing ECE and SVI. Both imaging modalities had similar specificity, sensitivity, and accuracy for determining BNI. However, both imaging modalities had low diagnostic accuracy for LNM on histopathology.

An intrathoracic schwannoma case in 18F-FDG PET/CT scan.

Positron emission tomography /CT images showed a moderately increased 18F-FDG uptake in the mass of left lung lower lobe superior segment (SUVmax: 2.71). No pathological 18F-FDG involvement was detected in another region of the whole body scan. The patient underwent tru-cut biopsy. Since histopathological diagnosis could not be made, thoracotomy was performed. Schwannomas are the second most common benign peripheral nerve sheath originated tumor. Due to its development from Schwann cells, it can be seen in all organs or tissues during intracranial, extracranial, or spinal nerve courses where these cells are found. Schwannomas are extremely rare in the lung, regardless of the patients age. Ohtsuka et al. (2005) stated that in the review of 62 patients with intrapulmonary or bronchial schwannoma (5-83 years; 28 male, 34 female patients), this neoplasm constitutes approximately 0.2% of all pulmonary neoplasms. Although it is usually sporadic and single lesion, it can also be seen with neurofibromatosis (NF)1 or NF2. Especially in schwannomatosis cases, NF2 is observed with multiple and benign characters. In patients with tumors located proximal to the lobar bronchus, atelectasis or pneumonia associated with cough and dyspnea may occur. However, most patients with peripheral intrapulmonary schwannoma have no symptoms. Fluorine-18 FDG-PET/CT is a useful imaging modality to separate malignant solitary pulmonary nodules from benign nodules. There are few cases of 18F-FDG PET/CT imaging intrapulmonary schwannoma in the literature. Maximum standard uptake values (SUVmax) of Schwannomas in 18F-FDG PET/CT are variable. SUVmax values are generally low and moderate, but have been shown to vary between 1.9-7.2. The reason for the variation in SUVmax is thought to be due to varying degrees of cellularity, microvascular density or vascular permeability. Histopathologically, dense cellular areas (Antony A) and more hypocellular areas (Antony B) specific to Schwannoma appear in varying proportions. Also, the structure formed by spindle schwann cells side-by-side within the fields of Antony (Verocay body) is characteristic. Surgical resection, endoscopic resection and yttrium aluminum garnet (YAG) laser resection were used for the treatment of primary intrapulmonary schwannoma. The contribution of 18F-FDG PET/CT in schwannoma is that it provides malign and benign distinctions of intrapulmonary masses. However, a cutoff for SUVmax has not been identified in the malignant benign distinction. The diagnosis must be verified histopathologically.

Detection of Pulmonary Embolism with Gallium-68 Macroaggregated Albumin Perfusion PET/CT: An Experimental Study in Rabbits.

This study was designed to evaluate the accuracy of detecting pulmonary embolism (PE) using the Technegas SPECT/CT combined with 68Ga PET/CT in a rabbit model. One hour after artificial PE (n = 6) and sham (n = 6) models were created, Technegas SPECT/CT ventilation and 68Ga-MAA PET/CT perfusion scan (V/Q scan) were performed. Ventilation imaging was performed first on all cases. Technegas SPECT/CT and 68Ga-MAA PET/CT images were evaluated by a nuclear medicine physician who recorded the presence, number, and location of PE on a per-lobe basis. The sensitivity, specificity, and accuracy of Technegas SPECT/CT and 68Ga-MAA PET/CT for detecting PE were calculated using a histopathological evaluation as a reference standard. A total of 60 lung lobes were evaluated in 12 rabbits, and PE was detected in 20 lobes in V/Q scans and histopathological analysis. The overall sensitivity, specificity, and accuracy were 100%, 100%, and 100%, respectively, for both the Technegas SPECT/CT and 68Ga-MAA PET/CT V/Q scans. Technegas/68Ga-MAA V/Q scans have good sensitivity, specificity, and accuracy in the detection of PE in this animal model study.

Intraobserver and interobserver agreement for the interpretation of 68Ga-prostate-specific membrane antigen-I&T positron emission tomography/computed tomography imaging.

OBJECTIVES: The use of Ga-prostate-specific membrane antigen positron emission tomography/computed tomography is spreading due to its clinical benefits. In this study, we aim to determine the intra- and interobserver agreement levels of Ga- prostate-specific membrane antigen-I&T positron emission tomography/computed tomography according to molecular imaging tumor-lymph node-metastases reporting system. MATERIALS AND METHODS: Eighty prostate cancer patients and underwent Ga- prostate-specific membrane antigen positron emission tomography/computed tomography were blindly evaluated twice by four nuclear medicine specialists at intervals of 4 weeks. The evaluations were performed according to molecular imaging tumour-lymph node-metastases (miTNM) classification. We used Cohen's Kappa and Fleiss' Kappa analysis to analyse intra- and interobserver agreements. RESULTS: When Ga-prostate-specific membrane antigen positron emission tomography/computed tomography findings were evaluated according to miTNM classification, the obtained kappa values were as follows. The intraobserver Cohen's kappa coefficient was found to be 0.79 (substantial agreement), 0.93 (almost perfect agreement), and 0.94 (almost perfect agreement) for miT, miN, and miM, respectively. During interobserver evaluation between the four observers, the kappa coefficient was 0.52 (moderate agreement) for miT, 0.74 (substantial agreement) for miN, and 0.84 (almost perfect agreement) for miM. CONCLUSION: There is no research on the intraobserver agreement analysis of Ga-prostate-specific membrane antigen positron emission tomography/computed tomography in the literature. Our findings are the first ones. The intraobserver agreement was almost perfect. Moreover, although Ga-prostate-specific membrane antigen I&T positron emission tomography/computed tomography had moderate interobserver evaluation compliance of the primary tumour, it had excellent interobserver agreement levels in local lymph node metastasis and distant metastasis evaluation.4012501255.

Incidental "Urinoma" in 18F-FDG PET/CT Scan

18F-FDG PET/CT scanning was performed for the primary staging of a 47-year-old man with urothelial carcinoma. The patient underwent biopsy by ureteroscopy 15 days ago and the PET images revealed 18F-FDG accumulation in the right retroperitenal region, compatible with an "urinoma".

99mTc-HMPAO brain perfusion single-photon emission computed tomography in children with Down syndrome: relationship to epilepsy, thyroid functions, and congenital heart disease.

In recent years, it has been possible for patients with Down syndrome to live longer with advanced medical treatment and social support. As a result, the problems of these patients, such as thyroid diseases, leukemia, and Alzheimer disease, would be encountered more frequently. In this study, we aimed to perform the brain perfusion of children with Down syndrome by technetium 99m hexamethylpropylene amine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) and to determine the relationship between brain perfusion and epilepsy, thyroid function tests, congenital heart disease, and level of mental and motor development. Thirty patients with Down syndrome, aged between 1 and 15 years, were included in our study. Demographic data, the existence of epilepsy and congenital heart defects, the level of mental and motor development, serum levels of thyroid hormones, and autoantibodies were determined. All patients underwent computed tomography (CT) and/or magnetic resonance imaging (MRI). Cerebral SPECT was performed in all cases to evaluate the brain perfusion pattern. According to the visual evaluation of cerebral SPECT results, hypoperfusion was detected in 11 cases (37%). Patients with cerebral hypoperfusion (group 1) and patients with normal cerebral perfusion (group 2) were compared. There was no difference between group 1 and group 2 in terms of demographic data, congenital heart defects, IQ levels, thyroid hormones, and autoantibodies, but the incidence of epilepsy was significantly higher in group 1 (P<.001). When motor and mental development levels were compared, it was found that cases in group 1 were significantly more retarded in personal-social and fine motor skills (P<.05). The present study showed that cerebral hypoperfusion in children with Down syndrome is mostly related to epilepsy and the other coexisting conditions, congenital heart disease and hypothyroidism. Patients with cerebral hypoperfusion also have more retarded developmental levels, especially in personal-social and fine motor skills.

Assessment of regional blood flow in cerebral motor and sensory areas in patients with spinal cord injury.

We assessed the presence and the degree of alteration of the regional blood flow (rCBF) as visualized by Tc-99m HMPAO brain rest SPECT in the sensory motor cortex and subcortical structure in spinal cord injury (SCI) patients, who suffered from various levels of motor and sensory function loss. Twenty-two patients (mean age: 42.1+/-13.4 years, 18 M, 4 F) and 11 control subjects (mean age: 32.2+/-6.4 years, 8 M, 3 F) participated in this study. The spinal cord injury group was consisted of 2 groups (14 paraplegic and 8 tetraplegic patients). The corticocortical rCBF ratios were calculated by using region of interests obtained from 34 cortical areas on coronal slices. Significantly reduced rCBF were measured from 11 cortical areas in tetraplegic patients and 11 cortical areas in paraplegic patients. Some of these areas were different in each group. In the tetraplegic group, significant reduction was observed in the following rCBF areas: left anterior cingulate gyrus, left medial supplementary motor area, bilateral front and back aspects of posterior cingulate gyrus, right lateral primary motor area, right medial primary sensory area, bilateral putamen, and right cerebellum. In the paraplegic group, reduced rCBF areas were as follows: bilateral anterior cingulate gyrus, right lateral supplementary motor area, left front aspect of posterior cingulate gyrus, left lateral primary motor area, bilateral back aspects of posterior cingulate gyrus, right medial primary sensory area, left lateral primary sensory area and bilateral putamen. In conclusion, in some of the movement-cortical and subcortical areas having significantly reduced blood flow in SCI may be helpful to demonstrate the disrupted areas of rCBF by SPECT. We believe that it may be useful if these findings should be considered during the evaluations related to the reorganization in SCI cases.

Evaluation of alveolo-capillary permeability in thyrotoxicosis using Tc-99m DTPA aerosol scintigraphy.

Surfactant secreted from type II pneumocytes plays an important role in alveolo-capillary permeability. In thyrotoxicosis, high levels of T3 receptors detected at these cells might affect the alveolo-capillary permeability due to increased serum thyroid hormone levels. The results by CO-diffusion capacity measurement in thyrotoxicosis are conflicting. Changes in alveolo-capillary membrane permeability resulting from thyrotoxicosis are not well established yet. This prompted us to investigate the alveolo-capillary permeability in thyrotoxic patients in comparison with CO-diffusing capacity. For this aim twenty-two non-smoking thyrotoxic patients (before treatment) and fifteen healthy voluntary controls underwent 99mTc-DTPA aerosol scintigraphy. CO-diffusing and pulmonary function tests were performed in all subjects. After ventilation of radiotracer through a nebulizer for 15 minutes, 30 dynamic images (1 frame/minute) were taken from both lungs. ROI's were drawn over both lung areas, and the time-activity curves were generated. Then clearance half time (CT1/2) for radioaerosol was obtained. CT1/2 of thyrotoxic patients did not differ from that of the controls: 77.9 +/- 25.9 min vs. 79.4 +/- 22.3 min; p > 0.05. Similar result was found for CO-diffusion parameters. Also there was no significant correlation between CT1/2 and CO-diffusion parameters. We concluded that in patients with thyrotoxicosis, the alveolo-capillary permeability is unaffected. Further experimental research is needed to establish the possible effects of thyroid hormones on alveolo-capillary membrane.

Normalization of negative T waves in the chronic stage of Q wave anterior myocardial infarction as a predictor of myocardial viability.

We investigated whether spontaneous normalization of negative T waves (TWN) on infarct-related ECG leads (IRLs) in the chronic phase of Q wave anterior myocardial infarction (MI) could be a predictor of residual viability in infarct areas. We prospectively studied 35 patients (age 60 +/- 8.6 years) in the chronic phase of Q wave anterior MI. Spontaneous TWN (group A, n = 23) were defined as negative T waves that became upright (> or =0.15 mV) in > or =2 IRLs. The presence of negative T waves (group B, n = 12) was defined as symmetric or biphasic negative T wave of > or =0.15 mV. All patients underwent same-day rest 201Tl-stress (99m)Tc sestamibi dual-isotope myocardial perfusion SPECT and 24-hour 201Tl reinjection imaging for ischemia and viability analysis. On scintigraphic examination, ischemic or viable myocardial segments were found in 18 patients (78%) with TWN and 4 patients (33%) of group B (p = 0.013). The use of TWN as a parameter had a marked influence on the sensitivity (82%), specificity (62%), positive (78%) and negative (67%) predictive values and accuracy (74%) of the diagnosis of viable myocardium. If we add the criterion of positive T waves in aVR with negative T waves to our criteria, we found that sensitivity (90%), positive (80%) and negative (80%) predictive values and accuracy (80%) increased. The results of our study suggest that analysis of TWN on IRLs is an accurate marker of residual viability and/or persistent peri-infarct ischemia in patients in the chronic stage of Q wave anterior MI, and therefore optimizes the diagnostic and therapeutic strategies after MI.

The relationship between 99mTc-HMPAO brain SPECT and the scores of real life rating scale in autistic children.

Childhood autism is a developmental disability of unknown origin with probable multiple etiologies. The purpose of this study was to compare the changes of regional cerebral blood flow (rCBF) in autistic and non-autistic controls, and to determine the relationship between rCBF on 99mTc-hexamethylpropylene amine oxime (HMPAO) brain SPECT and the scores of the Ritvo-Freeman Real Life Rating Scale (RLRS), IQ levels, and age of autistic children. Eighteen autistic children (four girls, 14 boys; mean age: 6.13 +/- 1.99 years) and 11 non-autistic controls (five girls, six boys, mean age: 6.5 +/- 3.39 years) were examined using 99mTc-HMPAO brain SPECT. All the children satisfying DSM-IV criteria for autistic disorder were taken into evaluation, and scored by the Ritvo-Freeman RLRS. IQ levels of these children were determined by Goodenough IQ test. Six cortical regions of interest (ROIs; frontal (F), parietal (P), frontotemporal (FT), temporal (T), temporo-occipital (TO), and occipital (O)) were obtained on transaxial slices for count data acquisition. The ratio of average counts in each ROI to whole-slice counts for the autistic children was correlated with the scores of Ritvo-Freeman RLRS. Hypoperfusion in rCBF in autistic children compared with the control group were identified in bilateral F, FT, T, and TO regions. We found no relationship between rCBF on 99mTc-HMPAO brain SPECT and the scores of the Ritvo-Freeman RLRS. There was a relationship between bilateral F regions perfusion on 99mTc-HMPAO brain SPECT and the age of autistic children. There was also a negative correlation between IQ levels and the scores of sensory responses, social relationship to people, and sensory-motor responses. Our results suggest that 99mTc-HMPAO brain SPECT is helpful to locate the perfusion abnormalities but no correlation is found between rCBF on 99mTc-HMPAO brain SPECT and the scores of Ritvo-Freeman RLRS.