Comparison between 18F-FDG PET/CT and diffusion-weighted imaging in detection of invasive ductal breast carcinoma.

Objectives: Breast carcinoma is the most common type of cancer in females. This study aims to compare fluorine-18-fluorodeoxyglucose (18F-FDG) uptake pattern and apparent diffusion coefficient (ADC) value for the detection of the primary tumour and axillary metastases of invasive ductal breast carcinoma. Methods: This study included 40 breast carcinoma lesions taken from 39 patients. After staging by positron emission tomography-computed tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (MRI), breast surgery with axillary lymph node dissection or sentinel lymph node biopsy was performed. Results: Primary lesion detection rate for PET/CT and diffusion-weighted MRI was high with 39 of 40 lesions (97.5%). The sensitivity and specificity for the detection of metastatic lymph nodes in axilla were 40.9%, 88.9%, with 18F-FDG PET/CT scans and 40.9%, 83.3%, for dw-MRI, respectively. No significant correlation was detected between ADC and SUVmax or SUVmax ratios. Estrogen receptor (p=0.007) and progesterone receptor (p=0.036) positive patients had lower ADC values. Tumour SUVmax was lower in T1 than T2 tumour size (p=0.027) and progesterone receptor-positive patients (p=0.029). Tumour/background SUVmax was lower in progesterone receptor-positive patients (p=0.004). Tumour/liver SUVmax was higher in grade III patients (p=0.035) and progesterone receptor negative status (p=0.043). Conclusions: This study confirmed the high detection rate of breast carcinoma in both modalities. They have same sensitivity for the detection of axillary lymph node metastases, whereas the PET/CT scan had higher specificity. Furthermore, ADC, SUVmax and SUVmax ratios showed some statistical significance among the patient groups according to different pathological parameters.

Effects of bariatric surgery on knee osteoarthritis, knee pain and quality of life in female patients.

OBJECTIVES: Bariatric surgery is an effective intervention for severe obesity and associated comorbidities. We compared symptoms, joint space and life quality of morbidly obese patients with symptomatic knee osteoarthritis before and after bariatric surgery. METHODS: 34 patients with knee osteoarthritis were evaluated with standing anteroposterior and lateral radiography, medial and lateral joint distances of the knees, Visual Analog Scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire and the Short Form 36 (SF-36) before and 6 months after surgery. RESULTS: Mean patient age was 48.53±6.91 years. Mean body mass index was 46.97±6.04 kg/m2 and 34.41±5.62 kg/m2 before and after surgery, respectively. SF-36 subscales were significantly higher after surgery (p<0.05), while mean VAS values and WOMAC scores were significantly lower postoperatively (p<0.001). Right knee medial and left knee lateral joint distance measurements were significantly higher postoperatively (p<0.05). BMI change, in linear regression analysis had no significant effect on VAS, WOMAC, SF-36 and knee lateral and medial joint distance measurements. CONCLUSIONS: Although bariatric surgery might improve pain, life quality and functionality of knee osteoarthritis in early period, improvement is not directly related to weight loss amount.

Dual-Time 18F-FDG PET/CT Imaging in Initial Locoregional Staging of Breast Carcinoma: Comparison with Conventional Imaging and Pathological Prognostic Factors.

The aims of this retrospective study were to consider the diagnostic role of dual-time 18F-fluorodeoxyglucose positron emission tomography and computed tomography (18F-FDG PET/CT) in detection of breast carcinoma and axillary lymph node (ALN) status and to evaluate the primary tumor 18F-FDG uptake pattern. Preoperative staging was performed by 18F-FDG PET/CT in 78 female patients with breast carcinoma. Conventional imaging results were evaluated by breast magnetic resonance imaging (MRI) of 79 lesions in 78 patients, bilateral mammography (MMG) of 40 lesions in 40 patients, and breast ultrasonography (USG) of 47 lesions in 46 patients. The primary tumor detection rate using 18F-FDG PET/CT was higher than those using MRI, USG, and MMG. The sensitivity and specificity of 18F-FDG PET/CT scans for detecting multifocality were higher than those of MRI. The specificity of ALN metastasis detection with MRI was higher than that with 18F-FDG PET/CT, but 18F-FDG PET/CT had higher sensitivity. Higher 18F-FDG uptake levels were detected in patients with ALN metastasis, histologic grade 3, estrogen-progesterone-negative receptor status, lymphatic invasion, and moderate to poor prognostic groups. There was no statistical difference for the retention index in categorical pathological parameters except for progesterone-negative status. In conclusion, 18F-FDG PET/CT scans may be a valuable imaging technique for evaluating primary tumor and axillary status in staging breast carcinoma and 18F-FDG uptake may be a prognostic factor that indicates aggressive tumor biology and poor prognosis. Dual-time imaging in breast carcinoma staging may not be used for predicting pathological criteria and the aggressiveness of primary lesions.

The analysis of the maxillary sinus volumes and the nasal septal deviation in patients with antrochoanal polyps.

The aim of this study was to evaluate the relationship between the maxillary sinus volumes and the nasal septal deviation angles in patients with antrochoanal polyps (ACP). 76 patients who underwent ACP surgery were included in the study. Of those 36 patients who had multislice computed tomography (MSCT) were evaluated to calculate maxillary sinus volume. The records of paranasal MSCT of 36 healthy people without any paranasal sinus diseases or surgery constituted age- and gender-matched healthy controls. Maxillary sinüs volumes and septal deviation angles were calculated using the paranasal MSCT volume-rendering technique. Thirty-six patients in the ACP group were compared with 36 polyp side-matched healthy people. The mean age was 16.6 ± 6.7 years in both groups. Statistically, the mean value of the maxillary sinus volume was significantly higher in the ACP group compared with the ACP side-matched control group (15.1 ± 4.6 versus 12.0 ± 3.5 mm(3)) (p = 0.002). Furthermore, the mean value of the maxillary sinus volume in the non-polyp side (14.2 ± 4.7 mm(3)) was statistically higher in the ACP group compared with the side-matched control group volume (11.9 ± 3.8 mm(3)) (p = 0.024). In addition, Fifty-three of 76 ACP patients had septal deviation. While the septal deviation was on the same side with the ACP in 17 patients, it was on the opposite side in 36 patients. In conclusion, the maxillary sinus volumes increased in ACP patients compared with the healthy control group. Many patients had nasal septal deviation on the opposite side of the ACP.

Evaluation of resistive index by color Doppler imaging of orbital arteries in type II diabetes mellitus patients with microalbuminuria.

OBJECTIVE: Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage in ophthalmologic diseases. The purpose of this study was to evaluate the association between RI values of orbital arteries by using the color Doppler imaging (CDI) in type II diabetes mellitus (DM) patients with microalbuminuria. PATIENTS AND METHODS: We evaluated 91 type II DM patients with microalbuminuria and 27 healthy subjects. The DM patients with microalbuminuria were grouped into two: group 1 consisted of patients with retinopathy (n = 51) and group 2 consisted of patients without retinopathy (n = 40). Healthy subjects constituted group 3 (n = 27). The mean RI values of ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured using CDI. RESULTS: Compared to diabetic group 2, group 1 had significantly higher mean RIs of OA, CRA, PCA, and HbA1c levels (p < 0.001 for all). Besides, there were no statistical differences in mean RIs of OA, CRA, and PCA between the control group and group 2 (p = 1.0; p = 0.44; p = 0.67, respectively). Mean RIs of OA and PCA were significantly correlated with age in group 1 (r = 0.549, p < 0.001; r = 0.407, p = 0.003, respectively). Mean RI of CRA was significantly correlated with the duration of diabetes and age in group 1 (r = 0.296, p = 0.035; r = 0.486, p < 0.001, respectively). CONCLUSION: Our study indicates that RI might be a useful marker for early diagnosis and follow-up of diabetic retinopathy, and orbital RI assessment would be beneficial for diabetic patients with retinopathy.

[Kyphoplasty method for the treatment of traumatic osteoporotic vertebral compression fractures: case report]. / Travmaya bagli osteoporotik vertebra çökme kiriklarinin tedavisinde kifoplasti uygulamasi: Olgu sunumu.

The aim of the kyphoplasty method for the treatment of traumatic osteoporotic vertebral compression fractures in geriatric patients is to improve the patient's quality of life. In this report we present two elderly patients who were suffering of traumatic osteoporotic vertebral compression fractures and underwent successful kyphoplasties. Percutaneous kyphoplasty method for the surgical treatment of these fractures decreases the hospitalization, morbidity and mortality in these patients.

Vertebral body pneumatocyst in the cervical spine and review of the literature.

A pneumatocyst in the cervical spine is extremely rare and to our knowledge only a few reports have been published in the English literature. Although the etiology and natural course of vertebral body pneumatocyst is unclear, nitrogen gas accumulation is claimed. A 65-year-old-man was admitted to the emergency department with neck pain and numbness and incapacity in his both hands and fingers. The radiological images revealed a vertebral located pneumatocyst in the C4 cervical vertebra. In this report, we present a case of cervical pneumatocyst located in the C4 vertebral body. The clinical and radiological features and natural course of the pneumatocyst were evaluated.

Preoperative sonography of nonreducible inguinal masses in girls.

PURPOSE: Inguinal hernia is one of the most common surgical pathologies in childhood. Any of the abdominal organs can slide into the hernial sac and become incarcerated there. In girls, the fallopian tubes, ovaries, uterus, and-rarely-ovarian cysts can form the sliding component of an inguinal hernia. The aim of this study was to investigate the diagnostic value of preoperative sonographic examination in girls with nonreducible inguinal masses. METHODS: Nine girls ranging in age from 2 months to 8 years who were admitted to our clinic with nonreducible inguinal masses were included in the study. All patients underwent sonographic examination followed by surgery on the day of admission. RESULTS: A definitive diagnosis was obtained in 6 patients on preoperative sonographic evaluation, whereas 3 patients were misdiagnosed. One patient was diagnosed sonographically as having lymphadenopathy, but surgery revealed an ovarian cyst sliding into the hernial sac. A second patient was found to have an infected lymph node at surgery instead of a strangulated bowel loop as diagnosed on sonographic examination. In the third patient, the preoperative sonographic diagnosis was an ovarian cyst in the hernia sac, but surgery revealed a cyst of the canal of Nuck. CONCLUSION: Inguinal masses in young girls must be carefully evaluated, because the sonographic preoperative diagnosis may be misleading.

Effect of Aerodiol administration on ocular arteries in postmenopausal women.

OBJECTIVE: The aim of the present study was to evaluate the alteration of ocular blood hemodynamics after intranasal administration of 17beta-estradiol, through measurement of the ophthalmic artery (OA) and the central retinal artery (CRA) using color duplex sonography. METHODS: Thirty healthy women who had been naturally postmenopausal for at least 1 year were enrolled in the study. A randomized, placebo-controlled, crossover, double-blinded study was conducted of the acute effect of 17beta-estradiol (Aerodiol; Servier, Chambrayles-Tours, France) on OA and CRA blood flow using color duplex sonography. RESULTS: The peak systolic and end diastolic velocities of the CRA were increased significantly after 17beta-estradiol administration compared with placebo. A significant decrease was also found in the pulsatility and resistive indices of the CRA. However, there were no statistically significant differences in OA flow velocities or pulsatility and resistive indices. CONCLUSIONS: Nasal 17beta-estradiol administration in postmenopausal women causes an improvement in the ocular vascular Doppler indices. These results suggest that there could be a positive effect of Aerodiol on middle-sized arteries and arterioles.

Carotid hemodynamic parameters in hemodialysis patients.

BACKGROUND: Atherosclerotic vascular disease is a major cause of morbidity and mortality for patients with end-stage renal disease on maintenance hemodialysis. Early atherosclerotic changes of the arterial wall can be evaluated by intima-media thickness (IMT), presence and structure of plaques and parameters of vascular resistance. The aim of the present study has been to investigate the relationship between carotid IMT and pulsatility index (PI) or resistive index (RI) values in hemodialysis patients. METHODS: We studied 36 hemodialysis patients (21 female, 15 male; median age 39.5 years, IQR 33.0-54.7 years) and 38 healthy volunteers (20 women, 18 men; median age 41.0 years IQR 32.5-53.5 years). All subjects underwent ultrasonography of common carotid artery, with determination of IMT, PI and RI. RESULTS: Bilateral and mean carotid IMT were found to be significantly higher in hemodialysis patients than in the control group (P<0.0001). Right and left carotid artery RI values were determined to be lower in hemodialysis patients than in the control group (P=0.007 for both). Similarly, right and left carotid PI values were also determined significantly lower in the hemodialysis group (P=0.005 and P=0.004, respectively). There was a moderate negative correlation between the right carotid IMT and right PI (r=-0.258, P=0.026). CONCLUSIONS: In contrast to previous studies in patients with diabetes, hypertension or cerebrovascular disease, PI and RI values decrease when IMT increases in hemodialysis patients. This finding may be a result of peripheral vasodilatation secondary to anemia in hemodialysis patients.

The relationship between arteriovenous fistula blood flow rate and pulmonary artery pressure in hemodialysis patients.

PURPOSE: Although there is an increased prevalence of pulmonary hypertension in hemodialysis patients, the relationship between arteriovenous (AV) fistula blood flow and pulmonary hemodynamics is not known. The aim of this study was to evaluate the relationship between blood flow rate of AV fistula and pulmonary artery pressure (PAP) in hemodialysis patients. METHODS: Thirty-two hemodialysis patients were included in this study. Within 1 h of completion of dialysis, blood flow rate of AV fistula and pulmonary hemodynamics were evaluated using Doppler sonography. Pulmonary hypertension was defined as mean PAP > or = 25 mmHg at rest. RESULTS: Mean PAP, median blood flow rate of AV fistula, and mean cardiac index were 22.5 +/- 10.0 mmHg (range 8-39), 978.0 ml/min (interquartile range 762.0-1,584.5) and 3,043.0 +/- 694.3 ml/ min per m2 (range 1,251-4,140), respectively. Mean PAP has a relationship to cardiac index (r = 0.453, P = 0.014). However, there was no correlation between mean PAP and blood flow rate of AV fistula, hemoglobin, calcium-phosphorus (CaxP) product, and parathormone. Pulmonary hypertension was present in 43.7% of patients. Patients with pulmonary hypertension had significantly higher cardiac index (P = 0.036). CONCLUSIONS: We found there was no direct relationship between blood flow rate of AV fistula and PAP. Other factors may play a role in the development of pulmonary hypertension.

The effects of weight loss on normal transaminase levels in obese patients.

BACKGROUND: Obesity is associated with insulin resistance, which is the main pathogenic factor for nonalcoholic fatty liver disease (NAFLD). NAFLD can progress without associated elevations in liver enzymes. Therefore, we investigated the effects of weight loss on normal transaminase levels in obese subjects who are at risk for NAFLD. METHODS: Thirty-seven obese patients with normal ALT levels were evaluated. All patients received an individualized low-calorie diet over at least 6 months. Twenty-two patients who achieved weight loss of at least 5% body weight were identified as the study group and the others as the control group. Transaminases, insulin resistance, and body mass index were compared before and after the intervention. RESULTS: Hepatic steatosis was found in 83.8% of obese patients. ALT was correlated with HOMA-IR in all patients at baseline (r = 0.363, P = 0.027). At the end of the follow-up, mean weight loss achieved in the study and control groups were 9.2% (8.7 +/- 3.0 kg) and 0.3% (0.5 +/- 2.8 kg), respectively. In the study group, HOMA-IR and ALT decreased from 4.0 +/- 1.8 to 2.4 +/- 0.9 and from 21.4 +/- 6.6 IU/L to 16.8 +/- 5.5 IU/L, respectively (P = 0.005 and P = 0.044). CONCLUSIONS: The results demonstrate that weight loss results in a decrease in normal ALT levels as well as insulin resistance. Therefore, the normal range for ALT may need to be reassessed.

Large mycotic aneurysm of the peroneal artery.

We describe the case of a 37-year-old patient with mycotic aneurysm of the right peroneal artery associated with episodes of endocarditis. There are only 7 cases of mycotic aneurysms of the crural arteries reported in the literature. To the best of our knowledge, this is the first reported case of a mycotic aneurysm of the peroneal artery in an adult.

Hemodynamic changes in the cephalic vein of patients with hemodialysis arteriovenous fistula.

PURPOSE: To assess via Doppler sonography the hemodynamic changes in the cephalic vein after creation of an arteriovenous fistula, and to compare radiocephalic and brachiocephalic fistulas. METHODS: Thirty-three hemodialysis patients and 54 controls were enrolled in the study. The cephalic vein was examined with a 7.5-MHz linear-array transducer. Doppler waveform parameters (resistance index, pulsatility index), time-averaged maximum flow velocity (TAV), peak systolic velocity (PSV), end-diastolic velocity (EDV), and the cross-sectional area of the vessel (A) were measured. Cephalic vein flow volume (CVFV) was calculated as TAV x A. RESULTS: CVFV, PSV, EDV, A, RI, and PI were 45.5, 7.2, 6.7, 7.7, 1.2, and 1.32 times higher, respectively, in the cephalic vein of hemodialysis patients compared with controls. Both CVFV and A were higher in brachiocephalic patients compared with radiocephalic patients (1,983 +/- 1,199 versus 870 +/- 322 ml/min [p < 0.05] and 50.3 +/- 38.9 versus 21.0 +/- 7.8 mm(2) [p < 0.05], respectively). CONCLUSION: The increase in cross-sectional area and flow volume of the cephalic vein is larger in patients with brachiocephalic fistulas than in those with radiocephalic fistulas; however, flow velocities and waveform parameters are not different.

The effects of levodopa use on diffusion coefficients in various brain regions in Parkinson's disease.

We aimed to evaluate the effects of l-dopa use on apparent diffusion coefficient (ADC) values of different brain regions in Parkinson's disease (PD) patients. Thirty-five subjects underwent magnetic resonance imaging (MRI), including 21 PD patients (13 men, 8 women; mean age, 63 years+/-8), and 14 sex and age-matched control subjects. PD patients were separated into two groups according to the duration of l-dopa usage: patients using l-dopa less and more than 1 year. According to the disease duration two other groups were formed: patients diagnosed less and more than 1 year. Unified Parkinson Disease Rating Scale (UPDRS) scores of PD patients were detected. Diffusion weighted images (DWI) and ADC maps of patients and controls were evaluated and regional ADC (rADC) measurements were performed. Patients' age was not significantly different between groups. UPDRS was significantly different between the patient groups. There was no significant difference of rADC values between PD and control groups, and within the different PD groups. Short- and long-term l-dopa usage in PD patients did not cause any change rADC values in various brain regions.

Cerebral and cerebellar ADC values during a migraine attack.

INTRODUCTION: We investigated the diffusion-weighted MRI changes, apparent diffusion coefficient (ADC) values, and conventional MRI findings in specific brain areas during migraine attacks in patients with and without aura. METHODS: Included in the study were 22 patients (2 male, 20 female) aged between 17 and 49 years who were diagnosed as having migraine according to the diagnostic criteria of the International Headache Society. Also included in the study were 18 age- and sex-matched healthy volunteers. Hyperintense lesions were evaluated in conventional MR images. Heavily diffusion-weighted images, ADC maps, and segmented ADC maps generated for regional ADC (rADC) measurements, were also studied. ADC values from specific brain areas were used with appropriate region of interests (ROI). RESULTS: Migraine with aura was diagnosed in 13 patients and migraine without aura was diagnosed in 9 patients. A total of 23 hyperintense lesions within the periventricular white matter and deep white matter were detected in five patients (21.8%). All of these hyperintense lesions were seen in migraine patients with aura. In only one patient did a hyperintense lesion show an increased diffusion pattern on diffusion-weighted images and ADC maps. One hyperintense lesion was detected in the control group (5.5%). There was no significant difference in ADC values between the migraine and control groups. CONCLUSION: T2-weighted hyperintense lesions were significantly more frequent in migraine patients especially in those with aura than in the control group. No diffusion alterations in diffusion-weighted images were detected in the infra- and supratentorial brain areas during migraine attacks in patients with and without aura.

Doppler sonography evaluation of flow velocity and volume of the extracranial internal carotid and vertebral arteries in healthy adults.

PURPOSE: To measure with Doppler sonography the velocity and volume of blood flow in the extracranial internal carotid artery (ICA) and vertebral artery (VA) of healthy adults and to calculate total cerebral blood flow volume (tCBFV). METHODS: Bilateral ICA and VA were examined sonographically in 180 healthy adults. Angle-corrected peak systolic (Vps), end-diastolic (Ved), and time-averaged maximum blood flow velocity (TAV) were measured in pulsed Doppler mode, and the resistance index (RI) and pulsatility index (PI) were calculated. The cross-sectional area (A) was measured on gray-scale images. Volume flow was calculated as FV = TAV x A, and tCBFV was calculated as the sum of the right and left ICA and VA volume flow. RESULTS: tCBFV was 651 +/- 96 ml/min for the entire population. There was a significant decrease in Vps, Ved, TAV, and tCBFV with age in all arteries. RI and PI values initially declined and then increased with age. Cross-sectional area increased with age in ICA but not in VA. PI and RI were higher in men than in women. Blood flow velocity and volume were higher, and RI was lower in the left than in the right VA. CONCLUSION: The Doppler sonographic assessment of extracranial ICA and VA blood flow volume may be useful for the study of cerebral hemodynamic changes in patients with cerebrovascular disorders. Age-dependent changes should be considered, for instance, in the management of intensive care patients with impaired cerebral perfusion.

Acute effect of smoking on gallbladder emptying and refilling in chronic smokers and nonsmokers: a sonographic study.

AIM: To ultrasonographically evaluate the acute effects of smoking on gallbladder contraction and refilling in chronic smokers and nonsmokers. METHODS: Fifteen chronic smokers (21-30 years old) and fifteen nonsmokers (21-35 years old) participated in this study. Chronic smokers were selected among the volunteers who had been smoking for at least 5 years and 10 cigarettes per day (mean 17.5/d). Examinations were performed in two separate days. In the first day, basal gallbladder (GB) volumes of volunteers were measured after 8-h fasting. After the examinations, participants had a meal containing at least 30-40 gram fat. Gallbladder volume was assessed at 5, 15, 30, 60, 120 and 180 min after the meal. In the second day, participants smoked 2 cigarettes after 8-h fasting. Then, they had the same meal, and gallbladder measurements were repeated at the same time points. Same procedures were applied to both groups. RESULTS: The mean starving GB volumes were 23.3 +/- 3.3 mL in the first day, 21.9 +/- 3.0 mL in the second day in nonsmoker group and 18.3 +/- 3.0 mL in the first day, 19.5 +/- 2.8 mL in second day in smoker group. There was no significant difference between starving GB volumes. We did not find any significant difference between the GB volumes measured at 5, 15, 30, 60, 120 and 180 min in the first and second days in nonsmoker group. In smokers, post cigarette GB volume was found significantly higher at 5, 15 and 30 min which corresponded to GB contraction phase (P < 0.05). Control GB volume measurements were not significantly different between the two groups. Post-smoking GB volumes were also not significantly different between the two groups. CONCLUSION: Smoking prolongs the maximal GB emptying time both in smokers and in nonsmokers though it is not significant. It delays GB contraction in chronic smokers and causes a significant decrease in GB emptying volume. Smoking causes no significant delay in GB refilling in both smokers and nonsmokers. These effects of smoking observed in acute phase result in bile stasis in GB. Bile stasis is the underlying cause of most GB disorders in chronic process.

Effects of sildenafil citrate (Viagra) on renal arteries: an evaluation with Doppler ultrasound.

INTRODUCTION: We aimed to determine hemodynamic alterations in renal arteries that may have resulted from oral intake of sildenafil citrate in healthy volunteers. MATERIALS AND METHODS: Twelve healthy volunteers were included in our study. Renal Doppler ultrasonography (US) was performed before the drug intake to assess the basal values. Maximum peak systolic velocity, and resistivity and pulsatility indices were measured from the segmental branches of both renal arteries in all the examinations. After the basal measurements 50 mg of sildenafil or placebo were randomly given to the 12 subjects. Renal Doppler US examinations were carried out 1 h after sildenafil or placebo intake. On the following day sildenafil was administered to the subjects who had previously taken placebo or vice versa. Renal Doppler US was repeated after 1 h. The effect of sildenafil on renal vascular hemodynamics was evaluated by comparison of basal values with postplacebo and postsildenafil values. RESULTS: No statistically significant differences were found between the basal values of bilateral renal arteries and maximum peak systolic velocity, and resistivity and pulsatility index values measured after the placebo or sildenafil intake. CONCLUSION: We demonstrated that single-dose sildenafil did not cause any significant effect on renal artery hemodynamics in healthy individuals.