Enhancing PSMA PET/CT imaging of prostate cancer: investigating the impact of multiple time point evaluation, diuretic administration, cribriform pattern, and intraductal carcinoma.

OBJECTIVE: Our objective was to correlate staging PSMA PET imaging parameters to final histopathology. Second objective was to assess the performance of standard versus delayed PSMA PET to detect primary prostate tumor. METHODS: Thirty-one patients (mean age, 61.4 ± 8.2) who underwent radical prostatectomy and preoperative staging PSMA PET scans were included in the study. After defining dominant lesion in pathology, correlations with PET images were performed. Additionally, two physicians blind to clinical and pathological information retrospectively reviewed staging Ga-68 PSMA PET scans with standard and delayed imaging. RESULTS: Dominant lesion SUV's increased with time 8.2(± 4.5), 10(± 7.1), and 10.2(± 7.8) at 1, 2, and 3 h (P = .03 T1-T3). WHO Grade group 3 had highest SUV (group 3 11.9 ± 5.6 vs. group 2 7.9 ± 1.5, p = .02). Addition of cribriform pattern on intraductal component was associated with higher SUV's (11 ± 2.9 vs. 6.5 ± 2.1, p = .01) and higher Gleason four ratios (64 ± 9% vs. 37 ± 17%, p = .01). Intraductal carcinoma was associated with larger tumors (6.3 ± 2.3 cm3 vs. 2.6 ± 1.7 cm3, p < .001). Physician sensitivities ranged from 61 to 81%. Excluding Gleason 3 + 3 lesions and small lesions (< 1 cm3), sensitivities increased to 80-100%. Differences of sensitivity between different time points were not significant. Combined evaluation of all time points did not increase sensitivity. CONCLUSIONS: Cribriform pattern correlates with higher Gleason 4 ratios and SUVs in PSMA PET. Intraductal carcinoma is associated with larger tumors but not higher Gleason 4 ratios and SUVs. Multiple late imaging times did not enhance tumor detection and may pose tolerability issues for some patients.

Validation of bioelectrical impedance analysis in the evaluation of body composition in patients with breast cancer.

BACKGROUND: The evaluation of body composition is an essential parameter for preventing obesity and sarcopenic obesity, which are prognostic factors in breast cancer. This study aims to validate the bioelectrical impedance analysis (BIA) of women who are breast cancer survivors by using the dual-energy x-ray absorptiometry (DXA) measurement method. METHODS: This validation study included 104 women without metastasis between 32 and 72 years old (mean 47.03 ± 8.59) whose treatment was completed 6 months prior. Body composition analysis was performed sequentially using both measurements and when participants were hungry. RESULTS: Meaningful differences were found in fat-free mass (FFM) (BIA: 46.57 ± 5.54 kg; DXA: 41.06 ± 5.11 kg), body fat percentage (%BF) (BIA: 34.28% ± 6.24%; DXA: 43.91% ± 5.58%), body fat mass (FM) (BIA: 25.37 ± 8.84 kg; DXA: 31.24 ± 9.09 kg), and lean soft tissue mass (LSTM) (BIA: 4.42 ± 5.66 kg; DXA: 38.75 ± 4.98 kg) (P < 0.001). Powerful associations for body FM and strong associations for other parameters were seen. A constant and/or proportional error was found between the two devices within the direction of strong and solid components. Compared with DXA, the BIA measurement gives a lower estimate of %BF and FM and a higher estimate of LSTM and FFM. CONCLUSIONS: By the mathematical relationship between the two measurement methods, it seems possible to adapt the body composition parameters obtained from BIA of patients with breast cancer to DXA results. In the future, there will be a need to evaluate these two devices with more extensive studies.

Optimizing the Personalized Care for the Management of Rectal Cancer: A Consensus Statement.

Colorectal cancer is the third most common cancer in Turkey. The current guidelines do not provide sufficient information to cover all aspects of the management of rectal cancer. Although treatment has been standardized in terms of the basic principles of neoadjuvant, surgical, and adjuvant therapy, uncertainties in the management of rectal cancer may lead to significant differences in clinical practice. In order to clarify these uncertainties, a consensus program was constructed with the participation of the physicians from the Acibadem Mehmet Ali Aydinlar and Koç Universities. This program included the physicians from the departments of general surgery, gastroenterology, pathology, radiology, nuclear medicine, medical oncology, radiation oncology, and medical genetics. The gray zones in the management of rectal cancer were determined by reviewing the evidence-based data and current guidelines before the meeting. Topics to be discussed consisted of diagnosis, staging, surgical treatment for the primary disease, use of neoadjuvant and adjuvant treatment, management of recurrent disease, screening, follow-up, and genetic counseling. All those topics were discussed under supervision of a presenter and a chair with active participation of related physicians. The consensus text was structured by centralizing the decisions based on the existing data.

Physiological fluorodeoxyglucose uptake of spinal cord in adults.

OBJECTIVE: Physiological fluorodeoxyglucose (FDG) uptake of spinal cord needs to be correctly recognized during evaluation of whole-body PET scans, especially for oncological cases. Our aim was to analyze physiological cord FDG uptake and its relation to gender, age, body weight, environmental temperature and time to imaging. MATERIALS AND METHODS: PET scans of 254 patients in a single year, one patient for every working day were retrospectively selected. Temperature data were obtained from meteorology recordings. Maximum standard uptake value (SUVmax) of spinal cord at cervical and lower thoracic levels were noted. Spinal canal at L5 level, cerebellum and liver were used for normalization. Correlations with age, body weight, time to imaging and environmental temperature were analyzed. RESULTS: Cervical SUV was higher than thoracic SUV (2.5-2.3). Cervical and lower thoracic SUV's were strongly correlated, highest when corrected with L5 level vertebral canal and liver (corr coeff 0.84 and 0.75) and lowest with cerebellum (corr coeff 0.4). Cervical spinal cord FDG uptake was higher for females than males (2.6 to 2.4). Temperature and age did not change spinal cord uptake. There were weak positive correlations with body weight (corr coeff 0.16 and 0.28, cervical and thoracic). There was weak negative correlation of cervical uptake with time to imaging (corr coeff -0.17). CONCLUSION: Spinal cord FDG uptake at cervical and lower thoracic levels are strongly correlated. Females have slightly higher cervical SUV. Age and temperature does not change spinal cord FDG uptake in adults. Cord SUV's slightly increased with body weight.

Colonic Malignant Melanoma: 18F-FDG PET/CT Findings

Primary malignant melanoma occurs most often in the skin and much less frequently in the choroid layer of the eyes, in the leptomeninges, oral cavity, nasal mucosa, pharynx, esophagus, bronchus, under the nail and vaginal or anorectal mucosa. Primary melanoma of the gastrointestinal tract has been confirmed for lesions occurring in the esophagus, stomach, small bowel, and anorectum through several published reports, as these are the areas where melanocytes normally exist. The occurrence of primary malignant melanoma in the colon is relatively rare, because melanocytes are embryologically absent in the large bowel. Herein we report a patient whose colonic malignant melanoma was diagnosed and disseminated metastatic lesions were revealed with 18F-FDG PET/CT scan. There were multiple nodular lesions showing increased 18F-FDG uptake in both lungs. There was a soft tissue lesion with slightly increased 18F-FDG uptake, which extended to the intraluminal region of the thoracic esophagus. Increased metabolic activity was detected in the asymmetric stomach wall thickening site and in a soft tissue lesion located on the gall bladder wall that was filling the lumen. Multiple hypodense/hyper-metabolic lesions were identified in the liver. Multiple hyper-metabolic polypoid soft tissue lesions were visualized in almost the entire colonic segments. Multiple hyper-metabolic peritoneal implants were noted in all abdominal quadrants. Increased 18F-FDG uptake was detected at the right surrenal gland soft tissue lesion. There was a hyper-metabolic soft tissue lesion on the posterior wall of the rectum. Hyper-metabolic lytic lesions were seen at the thoracal and lumbar vertebrae, left scapula, left iliac bone, sacrum and left femur. There was no evidence of 18F-FDG avid skin lesions in both attenuation corrected and non-corrected images.

Evaluating the Role of Routine Prone Acquisition on Visual Evaluation of SPECT Images.

UNLABELLED: Attenuation artifacts reduce our ability to evaluate perfusion of affected myocardial segments. The aim of this study was to evaluate the impact of routine prone-position image evaluation within a stepwise visual interpretation of myocardial perfusion studies. METHODS: We have included 279 consecutive patients who were referred for evaluation of myocardial ischemia. All patients underwent routine electrocardiogram-gated supine SPECT imaging and non-electrocardiogram-gated prone-position SPECT imaging. Three nuclear medicine physicians interpreted the images in the following order: polar maps, supine images, raw images, motion-frozen gated images, and prone images, using a scale of 0-4. Segments with perfusion abnormalities were noted. RESULTS: All physicians reported lower proportions of equivocal evaluations after evaluating prone images (18.3% vs. 4.7%, 19% vs. 11.1%, and 12.2% vs. 6.1%, P < 0.0001, P = 0.0077, and P = 0.0125, respectively). At the prone stage, normalcy rates were 89%, 87%, and 91%. Two physicians had significantly increased normalcy rates at the prone stage (72%-89%, P = 0.039, and 66%-87%, P = 0.006). At the prone stage, a decision reversal to normal or probably normal was observed in 40% (29/72), 33% (17/51), and 43% (21/48). In men, apical, mid, and basal inferior walls and in women apical and mid parts of anterior walls were more likely to be attributed to attenuation. The 2 steps that increased normalcy rates for interpreters were the review of raw images and of prone images. CONCLUSION: Routine prone imaging increases interpretive certainty and interobserver agreement and changes the final evaluation in a substantial number of patients and significantly decreases the number of equivocal evaluations.

Discordant findings in patients with non-small-cell lung cancer: absolutely normal bone scans versus disseminated bone metastases on positron-emission tomography/computed tomography.

OBJECTIVE: At present, metastatic bone involvement is usually assessed using bone scintigraphy, which has a high sensitivity but a poor specificity. The objective of our study was to compare the sensibility of the 2-deoxy-2-[18F] fluoro-d-glucose positron emission tomography/computed tomography (F-18 FDG PET/CT) for the detection of bone metastasis in patients with non-small-cell lung cancer (NSCLC) whose technetium 99m methylenediphosphonate (Tc-99m MDP) bone scans were absolutely normal. MATERIAL AND METHODS: This study based on the retrospective analysis of 95 consecutive patients with histologically proven NSCLC who underwent F-18 FDG PET/CT and Tc-99m MDP bone scan at the Eskisehir Osmangazi University School of Medicine, Department of Nuclear Medicine between November 2006 and October 2008. Nineteen patients (19 of 95, 20%) with absolutely normal Tc-99m bone scan versus multiple high-grade F-18 FDG avid bony metastases on F-18 FDG PET/CT were selected for the review. Their ages ranged from 46 to 73 years (15 males and four females; mean: 57.2 years). RESULTS: Nine patients had squamous cell carcinoma, six had adenocarcinoma, three had large cell carcinoma and one had adenosquamous cell carcinoma. Tc-99m MDP bone scan that did not reveal bony abnormalities or radiotracer uptake was characteristic of benign disease (defined as absolutely normal) in these patients. Whereas, F-18 FDG PET/CT not only showed extremely disseminated heterogeneous nest-like high-grade FDG avid metastatic foci within the marrow cavity of the upper and lower thoracic spine, lumbar spine, pelvis, rib cages and bilateral proximal long bones, but also showed disseminated osteolytic bony metastases in these areas. CONCLUSION: Discordant findings of skeletal metastasis between Tc-99m MDP bone scans and F-18 FDG PET/CT imaging may be seen in 20% of the patients with NSCLC. F-18 FDG PET/CT could detect metastatic bone involvement more accurately than bone scintigraphy. Bone scans are insensitive to early bone marrow neoplastic infiltration. Assessment of glucose metabolism with FDG PET/CT can represent a more powerful tool to detect early bone metastases in lung cancer than with traditional bone scans.

Late brain stem radionecrosis seventeen years after fractionated radiotherapy.

The appearance of a new lesion several years after radiation treatment for a primary brain tumor may represent different kind of pathologies. We present a 24-year-old patient who suffered from right-sided hemiparesis and ataxic gait with a history of an operation due to left frontoparieal grade II fibrillary astrocytoma and fractioned radiotherapy. His cranial MRI study showed heterogeneous signal intensity of brain stem radionecrosis in the pons spreading through the mesencephalon and left brachium pontis. The leading diagnosis was high-grade glial tumor. The patient underwent stereotaxic biopsy and histopathological examination revealed radionecrosis. Radiation necrosis has a radiological appearance similar to various important pathologies. Tissue sampling for histopathological examination is mandatory for definite diagnosis and correct treatment of the disease.

TC-99m MIBI SPECT imaging in patients with lung carcinoma: is it a functional probe of multidrug resistance genes?

OBJECTIVE: Multidrug-resistance (MDR) phenotype concerns altered membrane transport that results in lower cell concentrations of cytotoxic drug in many cancer types, including lung cancer, and is related to the overexpression of a variety of proteins that act as adenosine triphosphate-dependent extrusion pumps. Tc-99m Sestamibi (MIBI) is a transport substrate for P-glycoprotein (Pgp) pump. In this study, we assessed the uptake and clearance of technetium-99m-2-hexakis 2-methoxyisobutylisonitrile (Tc-99m MIBI) from the tumor and its correlation with messenger RNA (mRNA) levels of Pgp, MDR-associated protein (MRP1), and lung resistance protein (LRP) in lung carcinoma. METHODS: This study was carried out on 19 patients (mean age, 60.1 +/- 2.07 years) with advanced-stage lung carcinoma. The tumor samples obtained by bronchoscopy were assessed to estimate the levels of Pgp, MRP1, and LRP expression on mRNA level by quantitative real-time reverse-transcription polymerase chain reaction. Tc-99m MIBI chest imaging was performed 15 and 180 minutes after injection of 740 MBq Tc-99m MIBI. The early (T/Be) and delayed (T/Bd) Tc-99m MIBI uptakes and washout rate (WR) of Tc-99m MIBI from the tumor were measured. RESULTS: No correlation was found between the T/Be Tc-99m MIBI uptake of tumors (T/Be) and the levels of Pgp mRNA, MRP1 mRNA, and LRP mRNA by reverse-transcription polymerase chain reaction. There was a correlation between the mean T/Bd Tc-99m MIBI uptake and Pgp expression of the tumors (P = 0.001, Spearman rho = - 0.702). There was a correlation between the WR of Tc-99m MIBI from the tumor and Pgp expression of the tumor (P = 0.000, Spearman rho = 0.875). Washout rate of Tc-99m MIBI was not related to the levels of MRP1 mRNA (P = 0.93, Spearman rho = 0.02) or LRP mRNA (P = 0.47, Spearman rho = 0.177). CONCLUSIONS: Increased WR of Tc-99m MIBI is related in Pgp over expression of the tumor. Tc-99m MIBI single photon emission computed tomography imaging may be a functional probe of overexpression of Pgp in patients with lung carcinoma. However, Tc-99m MIBI single photon emission computed tomography imaging cannot be used to identify the MDR involved in the MRP1 or LRP in these patients.

Detection of hibernate myocardium by 99mTc sestamibi gated SPECT during low-dose dobutamine infusion plus nitrate in patients with first acute myocardial infarction.

AIM: To investigate the role of Tc-MIBI gated SPECT imaging following the administration of low-dose dobutamine plus nitrate (LDD+nitrate) in the assessment of left ventricular function and the perfusion of hibernate myocardial tissue. METHODS: The study group comprised 29 patients diagnosed as having acute myocardial infarction. In the first month post-infarction, Tc-MIBI gated SPECT imaging was performed in all patients at rest-dobutamine stress and LDD+nitrate. Ejection fraction, end diastolic volume (EDV), end systolic volume (ESV), stroke volume, volume, extent score, and reversibility score values were calculated. RESULTS: The findings of Tc-MIBI gated SPECT imaging following the administration of LDD+nitrate and the rest Tc-MIBI gated SPECT findings revealed that while the levels of ejection fraction (P=0.004) and reversibility score (P=0.000) increased significantly, there was a significant decrease in EDV (P=0.001), ESV (P=0.001), volume (P=0.017), stroke volume (P=0.257) and extent score (P=0.039) values. CONCLUSION: The use of Tc-MIBI gated SPECT concomitantly with the administration of LDD+nitrate is useful in the determination of myocardial hibernation in patients with left ventricular failure following acute myocardial infarction.

Long-term effects of antilipidaemic therapy on left ventricular function in patients with dyslipidaemia: multigated radionuclide ventriculography study.

AIM: It has been reported that dyslipidaemia impairs left ventricular systolic (LVs) and diastolic (LVd) functions, irrespective of atherogenic effects, in the setting of coronary artery disease. The aim of the present study was to evaluate the effects of anti-lipidaemic therapy on LVs and LVd functions by means of multigated radionuclide ventriculography (RNV) in subjects with signs of dyslipidaemia and with preserved left ventricular function. METHODS: Eighteen patients with dyslipidaemia (eight men, 10 women, mean age 50+/-10 years) were included in the study. While the clinical examination and treadmill exercise test results were normal in all patients, low-density lipoprotein levels exceeded 160 mg . dl. Patients with medical conditions including coronary artery disease, hypertension, diabetes, cardiomyopathy and valvular heart disease which would influence left ventricular function were excluded from the study. RNV was performed in all subjects, taking into account the best septal position to differentiate the left ventricle from the right ventricle. The following parameters were calculated: ejection fraction, peak ejection rate (PER), time to peak ejection (TPER), a ejection rate (aER), a ejection fraction (aEF), Peak filling rate (PFR), time to peak filling rate (TPFR), a filling rate (aFR), a filling fraction (aFF). RESULTS: The low-density lipoprotein value decreased and the high-density lipoprotein value increased after statin therapy (P<0.001 and P<0.003, respectively). PER, aER and aFF significantly increased and TPER decreased as a consequence of statin therapy (respectively, P<0.05, P<0.05, P<0.05 P<0.05). CONCLUSION: Anti-lipidaemic therapy is effective in dyslipidaemic patients. RNV is a useful and non-invasive method for monitoring changes in ventricular function following anti-lipidaemic treatment strategies.

Regional distribution and extent of perfusion abnormalities, and the lung to heart uptake ratios during exercise thallium-201 SPECT imaging in patients with cardiac syndrome X.

BACKGROUND: Cardiac syndrome X is defined as angina-like chest pain with transient ischemic ST-segment changes during exercise and angiographically normal epicardial coronary arteries. Studies with myocardial perfusion imaging in this syndrome have indicated that some patients, but not all, have an abnormality on perfusion scan. However, the impact of these perfusion abnormalities on pulmonary thallium uptake is not clear in this group of patients. OBJECTIVE: To evaluate the regional distribution and extent of perfusion abnormalities, and the lung to heart (L:H) uptake ratios using exercise thallium-201 single-photon emission computed tomography (TI-201 SPECT) in patients with cardiac syndrome X. METHODS: The study group consisted of 31 selected cardiac syndrome X patients with regional perfusion abnormalities during exercise TI-201 SPECT imaging. A control group included 26 healthy subjects with normal coronary angiograms, exercise testing and exercise TI-201 SPECT imaging. Exercise TI-201 SPECT results were analyzed with further estimation of the L:H ratios, number and localization of regional perfusion defects, and their mean extent scores expressed in pixels and in per cent of the left ventricular wall. Twenty-two patients with known coronary artery disease were also included in the analysis of the L:H ratios. RESULTS: Multiple perfusion defects were detected in 13 (42%) patients and perfusion defects of single localization were detected 18 (58%) patients. All patients had reversible perfusion abnormalities: 21 (67.7%) had anterior, 14 (45.2%) had inferior and 12 (38.7%) had lateral localization of perfusion defects. The analysis of the extent of the perfusion defects revealed that the mean scores of the extent of the single regional defects were 38.61+/-43.8 pixels and those of multiregional defects were 106.1+/-55.2 pixels, which corresponded to 6.05+/-1.8% and 16.6+/-5.4% of the left ventricular wall defects, respectively. Patients with cardiac syndrome X had a significantly higher L:H ratio during exercise than the healthy subjects (0.46+/-0.02 versus 0.34+/-0.03, P<0.01). In addition, L:H ratios were found to be higher in patients with multiple perfusion defects (0.50+/-0.02) than in patients who had only anterior (0.45+/-0.08) or inferior (0.43+/-0.02) perfusion defects (P<0.05 for both). There were no statistically significant differences in the rest L:H ratios between the study and control groups. Also, no significant differences were observed in exercise L:H ratios between the cardiac syndrome X patients and the patients with coronary artery disease (0.46+/-0.02 versus 0.49+/-0.03, P>0.05). CONCLUSIONS: The results suggest that multiple perfusion defects in multiple vascular regions are relatively common in cardiac syndrome X patients, with the majority of these patients having at least one abnormal perfusion bed. Patients with this syndrome who have perfusion abnormalities also had significantly higher L:H ratios during exercise than did the control patients. Increased exercise L:H ratios were more prominent in patients with multiple perfusion defects.

Uptake of 2-[18F]fluoro-2-deoxy-D-glucose in uterine leiomyoma: imaging of four patients by coincidence positron emission tomography.

Uterine leiomyomas, benign tumours of the human uterus, are the most common uterine neoplasm and are composed of smooth muscle with varying amounts of fibrous connective tissue. As a functional imaging modality, 2-[F]fluoro-2-deoxy-D-glucose (F-FDG) positron emission tomography can be used to obtain information about glucose metabolism in tissues. In this study, the findings of the F-FDG scans of four patients who were suspected of having malignant gynaecological tumours because of clinical and radiological findings and finally diagnosed as uterine leiomyoma based on histopathological examination were evaluated. Moderately intense F-FDG accumulation was detected in uterine mass localization in lower pelvis. The reason for the accumulation of F-FDG in uterine leiomyomas is not known. It may be explained by the existence of higher levels of growth factors, including basic fibroblast growth factor, transforming growth factor beta, granulocyte-macrophage colony-stimulating factor and receptors, and proliferation of smooth muscle cells in leiomatous uterus.

Tc-99m MIBI uptake and its relation to the proliferative potential of brain tumors.

PURPOSE: Many studies have shown that the S-phase fraction is a reflection of the proliferation potential of tumors, and DNA aneuploidy is more common in malignant tumors. In this preliminary study, the authors assessed the Tc-99m MIBI uptake of brain tumors and its relation to tumor grade and DNA content of the tumor cells. METHODS: Ten patients (eight male, two female; mean age, 53.2 +/- 6.11 years) with untreated brain tumors were included in the study. SPECT imaging was performed 20 minutes after injection of 740 MBq (20 mCi) Tc-99m MIBI. A single detector camera with a low-energy high-resolution collimator was used for image acquisition. A region of interest was drawn in the tumor area under magnetic resonance guidance. A Tc-99m MIBI uptake index was computed as the mean tumor-to-background ratio. Flow cytometric analysis of fresh tumor tissue specimens was performed immediately. The percentages of cells in the G0/G1, S, and G2/M phases were determined for each patient. RESULTS: DNA aneuploidy was found in 4 (49%) patients, whereas diploidy was found in 6 (60%) patients. There was a significant positive correlation between the Tc-99m MIBI uptake and the percentage of the S-phase fraction of the cell cycle ( = 0.000, r = 0.95). The Tc-99m MIBI index was significantly greater in aneuploid tumors than in diploid tumors ( < 0.01). CONCLUSIONS: High-grade brain tumors have increased Tc-99m MIBI uptake compared with that of low-grade tumors. Tc-99m MIBI uptake is correlated with the percentage of the S-phase fraction of the cell and the aneuploidy level of the brain tumor. This preliminary report suggests that Tc-99m MIBI imaging may be useful in the evaluation of the biologic characteristics of brain tumors.

Cerebral hemodynamic patterns with technetium Tc 99m exametazime single photon emission computed tomography and transcranial Doppler sonography: a validation study using visual stimulation.

OBJECTIVE: To assess whether a correlation between perfusion changes to visual stimulus on the bilateral occipital areas and blood flow velocity changes to visual stimulus in both posterior cerebral arteries is present. METHODS: Nine right-handed healthy subjects (4 women and 5 men; mean +/- SD age, 58.0 +/- 5.6 years) were included in the study. Visual stimulation was performed in room light with the subject's eyes open and looking around versus eyes closed as the stimulus-off condition. The blood flow velocities were recorded using transcranial Doppler sonography, and the regional cerebral blood flow measurements were recorded with the use of technetium Tc 99m exametazime and a single photon emission computed tomographic gamma camera system. Individual reactivity was defined as a relative increase of blood flow velocity and perfusion, which were calculated as percentage changes of baseline values. RESULTS: Visual stimuli produced a marked increase of blood flow velocity in both posterior cerebral arteries (35.2 +/- 2.3 cm/s; P < .001) without a significant side-to-side difference in all subjects as well as a marked increase of perfusion on both occipital areas (24.9 +/- 4.8 cm/s; P < .01). Moreover, there was a positive correlation between blood flow velocity changes and perfusion changes on both sides (r = 0.833; P < .01). CONCLUSIONS: The use of bilateral simultaneous Doppler recordings by means of a flow velocity averaging algorithm to a specific stimulus allows quantitative assessment of blood flow responses, and simple visual stimuli can be applied for different disorders to assess the vasomotor regulation that may result in measurable abnormal cerebral flow regulation even when clinically stabilized.