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Robert J Herfkens

Publications and source records attributed to Robert J Herfkens.

At least 19 recordsLinked to original sources
PubMed2006

Water-selective spectral-spatial contrast-enhanced breast MRI for cancer detection in patients with extracapsular and injected free silicone.

OBJECTIVE: This study investigates the use of contrast-enhanced, T1-weighted, water-selective spectral-spatial 3D gradient echo magnetic resonance imaging (MRI) with magnetization transfer (3DSSMT) for detecting breast cancer in patients with intraparenchymal silicone. CONCLUSION: Water-selective 3DSSMT provides superior fat and silicone suppression in patients with free silicone as compared with conventional fat saturation. It enables direct, high-quality, high-spatial-resolution, T1-weighted breast MRI of contrast enhancement without the need for subtraction processing and aids diagnosis of cancer in the breast with free silicone.

Adult↗
PubMed2006

Indirect MR lymphangiography of the head and neck using conventional gadolinium contrast: a pilot study in humans.

PURPOSE: To evaluate indirect magnetic resonance lymphangiography (MR-LAG) using interstitial injection of conventional gadolinium contrast (gadoteridol and gadopentetate dimeglumine) for delineating the primary lymphatic drainage of head-and-neck sites. METHODS AND MATERIALS: We performed head-and-neck MR-LAG in 5 healthy volunteers, with injection of dermal and mucosal sites. We evaluated the safety of the procedure, the patterns of enhancement categorized by injection site and nodal level, the time course of enhancement, the optimal concentration and volume of contrast, and the optimal imaging sequence. RESULTS: The worst side effects of interstitial contrast injection were brief, mild pain and swelling at the injected sites that were self-limited. MR-LAG resulted in consistent visualization of the primary lymphatic drainage pattern specific to each injected site, which was reproducible on repeated examinations. The best enhancement was obtained with injection of small volumes (0.3-0.5 mL) of either agent diluted, imaging within 5-15 min of injection, and a three-dimensional fast spoiled gradient echo sequence with magnetization transfer. CONCLUSIONS: We found head-and-neck MR-LAG to be a safe, convenient imaging method that provides functional information about the lymphatic drainage of injected sites. Applied to head-and-neck cancer, it has the potential to identify sites at highest risk of occult metastatic spread for radiotherapy or surgical planning, and possibly to visualize micrometastases.

Adult↗
PubMed2006

Abdominal aortic hemodynamics in young healthy adults at rest and during lower limb exercise: quantification using image-based computer modeling.

Localization of atherosclerotic lesions in the abdominal aorta has been previously correlated to areas of adverse hemodynamic conditions, such as flow recirculation, low mean wall shear stress, and high temporal oscillations in shear. Along with its many systemic benefits, exercise is also proposed to have local benefits in the vasculature via the alteration of these regional flow patterns. In this work, subject-specific models of the human abdominal aorta were constructed from magnetic resonance angiograms of five young, healthy subjects, and computer simulations were performed under resting and exercise (50% increase in resting heart rate) pulsatile flow conditions. Velocity fields and spatial variations in mean wall shear stress (WSS) and oscillatory shear index (OSI) are presented. When averaged over all subjects, WSS increased from 4.8 +/- 0.6 to 31.6 +/- 5.7 dyn/cm2 and OSI decreased from 0.22 +/- 0.03 to 0.03 +/- 0.02 in the infrarenal aorta between rest and exercise. WSS significantly increased, whereas OSI decreased between rest and exercise at the supraceliac, infrarenal, and suprabifurcation levels, and significant differences in WSS were found between anterior and posterior sections. These results support the hypothesis that exercise provides localized benefits to the cardiovascular system through acute mechanical stimuli that trigger longer-term biological processes leading to protection against the development or progression of atherosclerosis.

Adult↗
PubMed2006

Aortoiliac hemodynamic and morphologic adaptation to chronic spinal cord injury.

BACKGROUND: Reduced lower limb blood flow and resistive hemodynamic conditions potentially promote aortic inflammation and aneurysmal degeneration. We used abdominal ultrasonography, magnetic resonance imaging, and computational flow modeling to determine the relationship between reduced infrarenal aortic blood flow in chronic spinal cord injury (SCI) subjects and risk for abdominal aortic aneurysm (AAA) disease. METHODS: Aortic diameter in consecutive SCI subjects (n = 123) was determined via transabdominal ultrasonography. Aortic anatomic and physiologic data were acquired via magnetic resonance angiography (MRA; n = 5) and cine phase-contrast magnetic resonance flow imaging (n = 4) from SCI subjects whose aortic diameter was less than 3.0 cm by ultrasonography. Computational flow models were constructed from magnetic resonance data sets. Results were compared with those obtained from ambulatory control subjects (ultrasonography, n = 129; MRA/phase-contrast magnetic resonance flow imaging, n = 6) who were recruited at random from a larger pool of risk factor-matched individuals without known AAA disease. RESULTS: Age, sex distribution, and smoking histories were comparable between the SCI and control groups. In the SCI group, time since injury averaged 26 +/- 13 years (mean +/- SD). Aortic diameter was larger (P < .01), and the prevalence of large (> or = 2.5 cm; P < .01) or aneurysmal (> or = 3.0 cm; P < .05) aortas was greater in SCI subjects. Paradoxically, common iliac artery diameters were reduced in SCI subjects (< 1.0 cm; 48% SCI vs 26% control; P < .0001). Focal preaneurysmal enlargement was noted in four of five SCI subjects by MRA. Flow modeling revealed normal flow volume, biphasic and reduced oscillatory flow, slower pressure decay, and reduced wall shear stress in the SCI infrarenal aorta. CONCLUSIONS: Characteristic aortoiliac hemodynamic and morphologic adaptations occur in response to chronic SCI. Slower aortic pressure decay and reduced wall shear stress after SCI may contribute to mural degeneration, enlargement, and an increased prevalence of AAA disease.

Aorta, Abdominal↗
PubMed2006

In vivo MR angiographic quantification of axial and twisting deformations of the superficial femoral artery resulting from maximum hip and knee flexion.

PURPOSE: The goal of this study was to quantify in vivo deformations of the superficial femoral artery (SFA) during maximum knee and hip flexion with use of magnetic resonance (MR) angiography to improve description of the complex, dynamic SFA environment. MATERIALS AND METHODS: Contrast medium-enhanced MR angiography was performed on the leg vasculature of eight healthy adults in the supine and fetal positions. The SFA was defined as the centerline path of the iliofemoral segment from the profunda femoris to the descending genicular artery. Deformations that resulted from flexion from the supine position to the fetal position were quantified with the SFA path and its branches. RESULTS: Fourteen SFAs shortened from the supine position to fetal position, whereas two lengthened. Six of eight left SFAs twisted counterclockwise, and seven of eight right SFAs twisted clockwise. Straightness percentages for supine and fetal SFAs were 99.1%+/-0.4% and 98.7%+/-0.6%, respectively. From the supine position to the fetal position, the SFA shortened 13%+/-11% (P<.001) and twisted 60 degrees+/-34 degrees (P<.001). SFA arc length and percent shortening were strongly correlated (r>.8) between left and right limbs; however, no significant correlation existed for SFA twist angle. CONCLUSIONS: Complex and varying vascular and muscular anatomy among study participants made SFA lengths and deformations from the supine position to the fetal position unpredictable a priori; however, there were strong symmetries between left and right SFAs in terms of arc length, length change, and direction of twist. The data show that, from the supine position to the fetal position, the SFA tended to shorten and twist substantially, suggesting these as possible fracture mechanisms and also providing important parameters for stent design.

Adult↗
PubMed2005

Cardiac CINE imaging with IDEAL water-fat separation and steady-state free precession.

PURPOSE: To decompose multicoil CINE steady-state free precession (SSFP) cardiac images acquired at short echo time (TE) increments into separate water and fat images, using an iterative least-squares "Dixon" (IDEAL) method. MATERIALS AND METHODS: Multicoil CINE IDEAL-SSFP cardiac imaging was performed in three volunteers and 15 patients at 1.5 T. RESULTS: Measurements of signal-to-noise ratio (SNR) matched theoretical expectations and were used to optimize acquisition parameters. TE increments of 0.9-1.0 msec permitted the use of repetition times (TRs) of 5 msec or less, and provided good SNR performance of the water-fat decomposition, while maintaining good image quality with a minimum of banding artifacts. Images from all studies were evaluated for fat separation and image quality by two experienced radiologists. Uniform fat separation and diagnostic image quality was achieved in all images from all studies. Examples from volunteers and patients are shown. CONCLUSION: Multicoil IDEAL-SSFP imaging can produce high quality CINE cardiac images with uniform water-fat separation, insensitive to Bo inhomogeneities. This approach provides a new method for reliable fat-suppression in cardiac imaging.

Adult↗
PubMed2005

Proximal pulmonary artery blood flow characteristics in healthy subjects measured in an upright posture using MRI: the effects of exercise and age.

PURPOSE: To use MRI to quantify blood flow conditions in the proximal pulmonary arteries of healthy children and adults at rest and during exercise in an upright posture. MATERIALS AND METHODS: Cine phase-contrast MRI was used to calculate mean flow and reverse flow index (RFI) in the main (MPA), right (RPA), and left (LPA) pulmonary arteries in healthy children and adults in an open-MRI magnet equipped with an upright MRI-compatible ergometer. RESULTS: From rest to exercise (150% resting heart rate), blood flow (liters/minute/m2) increased in the RPA (1.4+/-0.3 vs. 2.5+/-0.4; P<0.001), LPA (1.1+/-0.3 vs. 2.2+/-0.6; P<0.001), and MPA (2.7+/-0.5 vs. 4.9+/-0.5; P<0.001). RFI decreased in the LPA (0.040+/-0.030 vs. 0.017+/-0.018; P<0.02) and MPA (0.025+/-0.024 vs. 0.008+/-0.007; P<0.03). Adults experienced greater retrograde flow in the MPA than the children (0.042+/-0.029 vs. 0.014+/-0.012; P<0.02). CONCLUSION: It appears that at both rest and during exercise, in children and adults alike, RPA/LPA mean blood flow distribution is predominantly determined by distal vascular resistance, while retrograde flow is affected by proximal pulmonary bifurcation geometry.

Adolescent↗
PubMed2005

Contrast-enhanced MRI of ductal carcinoma in situ: characteristics of a new intensity-modulated parametric mapping technique correlated with histopathologic findings.

PURPOSE: To identify morphologic and dynamic enhancement magnetic resonance imaging (MRI) features of pure ductal carcinoma in situ (DCIS) by using a new intensity-modulated parametric mapping technique, and to correlate the MRI features with histopathologic findings. MATERIALS AND METHODS: Fourteen patients with pure DCIS on pathology underwent conventional mammography and contrast-enhanced (CE) MRI using the intensity-modulated parametric mapping technique. The MR images were reviewed and the lesions were categorized according to morphologic and kinetic criteria from the ACR BI-RADS-MRI Lexicon, with BI-RADS 4 and 5 lesions classified as suspicious. RESULTS: With the use of a kinetic curve shape analysis, MRI classified seven of 14 lesions (50%) as suspicious, including four with initial-rapid/late-washout and three with initial-rapid/late-plateau. Using morphologic criteria, MRI classified 10/14 (71%) as suspicious, with the most prominent morphologic feature being a regional enhancement pattern. Using the intensity modulated parametric mapping technique, MRI classified 12/14 cases (86%) as suspicious. Parametric mapping identified all intermediate- and high-grade DCIS lesions. CONCLUSION: The intensity-modulated parametric mapping technique for breast MRI resulted in the highest detection rate for the DCIS cases. Furthermore, the parametric mapping technique identified all intermediate- and high-grade DCIS lesions, suggesting that a negative MRI using the parametric mapping technique may exclude intermediate- and high-grade DCIS. This finding has potential clinical implications.

Adult↗
PubMed2005

Time-resolved three-dimensional magnetic resonance velocity mapping of aortic flow in healthy volunteers and patients after valve-sparing aortic root replacement.

OBJECTIVE: To provide more complete characterization of ascending aortic blood flow, including vortex formation behind the valve cusps, in healthy subjects and patients after valve-sparing aortic root replacement (David reimplantation). METHODS: Time-resolved 3-dimensional magnetic resonance imaging velocity mapping was performed to analyze pulsatile blood flow by using encoded 3-directional vector fields in the thoracic aortas of 10 volunteers and 12 patients after David reimplantation using a cylindrical tube graft (T. David I) and two versions of neosinus recreation (T. David-V and T. David-V-S mod ). Aortic flow was evaluated by using 3-dimensional time-resolved particle traces and velocity vector fields reformatted onto 2-dimensional planes. Semiquantitative data were derived by using a blinded grading system (0-3: 0, none; 1, minimal; 2, medium; 3, prominent) to analyze the systolic vortex formation behind the cusps, as well as retrograde and helical flow in the ascending aorta. RESULTS: Systolic vortices were seen in both coronary sinuses of all volunteers (greater in the left sinus [2.5 +/- 0.5] than the right [1.8 +/- 0.8]) but in only 4 of 10 noncoronary sinuses (0.7 +/- 0.9). Comparable coronary vortices were detected in all operated patients. Vorticity was minimal in the noncoronary cusp in T. David-I repairs (0.7 +/- 0.7) but was prominent in T. David-V noncoronary graft pseudosinuses (1.5 +/- 0.6; P = .035). Retrograde flow (P = .001) and helicity (P = .028) were found in all patients but were not distinguishable from normal values in the T. David-V-S mod patients. CONCLUSIONS: Coronary cusp vorticity was preserved after David reimplantation, regardless of neosinus creation. Increased retrograde flow and helicity were more prominent in T. David-V patients. These novel magnetic resonance imaging methods can assess the clinical implications of altered aortic flow dynamics in patients undergoing various types of valve-sparing aortic root replacement.

Adult↗
PubMed2005

Magnetic resonance imaging characteristics of fibrocystic change of the breast.

OBJECTIVE: The objective of this study was to identify magnetic resonance imaging (MRI) characteristics of fibrocystic change (FCC) of the breast. MATERIALS AND METHODS: Fourteen patients with a histopathologic diagnosis of solitary FCC of the breast underwent x-ray mammography and MRI of the breast. Three experienced breast imaging radiologists retrospectively reviewed the MRI findings and categorized the lesions on morphologic and kinetic criteria according to the ACR BI-RADS-MRI Lexicon. RESULTS: The most striking morphologic feature of fibrocystic change was nonmass-like regional enhancement found in 6 of 14 (43%) FCC lesions. Based on morphologic criteria alone, 12 of 14 (86%) lesions were correctly classified as benign. According to analysis of the time-intensity curves, 10 of 14 (71%) FCC lesions were correctly classified as benign. CONCLUSION: Although FCC has a wide spectrum of morphologic and kinetic features on MRI, it most often presents as a mass or a nonmass-like regional enhancing lesion with benign enhancement kinetics.

Adult↗
PubMed2005

The lactating breast: contrast-enhanced MR imaging of normal tissue and cancer.

PURPOSE: To retrospectively describe the magnetic resonance (MR) imaging characteristics of normal breast tissue and breast cancer in the setting of lactation. MATERIALS AND METHODS: The HIPAA-compliant study was exempt from institutional approval, and informed consent was not required. Unilateral MR imaging of 10 breasts was performed in seven lactating patients aged 27-42 years. For the three patients in whom both breasts were imaged, each breast was imaged on a separate day. Nonenhanced T1-weighted and fat-saturated T2-weighted images and contrast material-enhanced dynamic three-dimensional (3D) T1-weighted spiral gradient-echo images interleaved with T1-weighted high-spatial-resolution 3D gradient-echo images (2.0 x 1.0 x 0.4-mm voxels) were obtained. Three readers in consensus assessed the glandular density, T2-weighted signal intensity, milk duct appearance, and contrast enhancement in normal and tumor-containing breast regions. The pharmacokinetic contrast enhancement parameters of tumors were compared with those of normal tissue by using Student t and Mann-Whitney tests. RESULTS: MR findings of normal breast tissue in the seven women included increased glandular density in six women, high T2-weighted signal intensity in six, dilated central ducts in seven, and rapid initial glandular contrast enhancement in seven. MR findings of invasive ductal carcinoma in five women, compared with findings of the normal glandular tissue, included lower T2-weighted signal intensity in five women, more avid and rapid contrast enhancement in five, and early contrast enhancement washout in four. One minute after contrast agent injection, tumor signal intensity increased significantly more than normal lactating tissue signal intensity (153% vs 60% from baseline, P = .016). The median two-compartment model K(21) exchange rate in the tumors, 0.078 sec(-1), was significantly faster than the K(21) exchange rate in normal tissue, 0.011 sec(-1) (P = .03). CONCLUSION: Normal lactating glands have increased density, high T2-weighted signal intensity, and rapid moderate contrast enhancement. Breast cancers are visible during lactation owing to their lower signal intensity and more intense initial contrast enhancement with early washout compared with normal breast tissue.

Adult↗
PubMed2004

Blood flow conditions in the proximal pulmonary arteries and vena cavae: healthy children during upright cycling exercise.

Diagnostic testing in patients with congenital heart disease is usually performed supine and at rest, conditions not representative of their typical hemodynamics. Upright exercise measurements of blood flow may prove valuable in the assessment of these patients, but data in normal subjects are first required. With the use of a 0.5-T open magnet, a magnetic resonance-compatible exercise cycle, and cine phase-contrast techniques, time-dependent blood flow velocities were measured in the right (RPA), left (LPA), and main (MPA) pulmonary arteries and superior (SVC) and inferior (IVC) vena cavae of 10 healthy 10- to 14-yr-old subjects. Measurements were made at seated rest and during upright cycling exercise (150% resting heart rate). Mean blood flow (l/min) and reverse flow index were computed from the velocity data. With exercise, RPA and LPA mean flow increased 2.0 +/- 0.5 to 3.7 +/- 0.7 (P < 0.05) and 1.6 +/- 0.4 to 2.9 +/- 0.8 (P < 0.05), respectively. Pulmonary reverse flow index (rest vs. exercise) decreased with exercise as follows: MPA: 0.014 +/- 0.012 vs. 0.006 +/- 0.006 [P = not significant (NS)], RPA: 0.005 +/- 0.004 vs. 0.000 +/- 0.000 (P < 0.05), and LPA: 0.041 +/- 0.019 vs. 0.014 +/- 0.016 (P < 0.05). SVC and IVC flow increased from 1.5 +/- 0.2 to 1.9 +/- 0.6 (P = NS) and 1.6 +/- 0.4 to 4.9 +/- 1.3 (P < 0.05), respectively. A 56/44% RPA/LPA flow distribution at both rest and during exercise suggests blood flow distribution is dominated by distal pulmonary resistance. Reverse flow in the MPA appears to originate solely from the LPA while the RPA is in relative isolation. During seated rest, the SVC-to-IVC venous return ratio is 50/50%. With light/moderate cycling exercise, IVC flow increases by threefold, whereas SVC remains essentially constant.

Adolescent↗
PubMed2004

Breast magnetic resonance image screening and ductal lavage in women at high genetic risk for breast carcinoma.

BACKGROUND: Intensive screening is an alternative to prophylactic mastectomy in women at high risk for developing breast carcinoma. The current article reports preliminary results from a screening protocol using high-quality magnetic resonance imaging (MRI), ductal lavage (DL), clinical breast examination, and mammography to identify early malignancy and high-risk lesions in women at increased genetic risk of breast carcinoma. METHODS: Women with inherited BRCA1 or BRCA2 mutations or women with a >10% risk of developing breast carcinoma at 10 years, as estimated by the Claus model, were eligible. Patients were accrued from September 2001 to May 2003. Enrolled patients underwent biannual clinical breast examinations and annual mammography, breast MRI, and DL. RESULTS: Forty-one women underwent an initial screen. Fifteen of 41 enrolled women (36.6%) either had undergone previous bilateral oophorectomy and/or were on tamoxifen at the time of the initial screen. One patient who was a BRCA1 carrier had high-grade ductal carcinoma in situ (DCIS) that was screen detected by MRI but that was missed on mammography. High-risk lesions that were screen detected by MRI in three women included radial scars and atypical lobular hyperplasia. DL detected seven women with cellular atypia, including one woman who had a normal MRI and mammogram. CONCLUSIONS: Breast MRI identified high-grade DCIS and high-risk lesions that were missed by mammography. DL detected cytologic atypia in a high-risk cohort. A larger screening trial is needed to determine which subgroups of high-risk women will benefit and whether the identification of malignant and high-risk lesions at an early stage will impact breast carcinoma incidence and mortality.

Adult↗
PubMed2004

Quantification of vessel wall motion and cyclic strain using cine phase contrast MRI: in vivo validation in the porcine aorta.

Artery wall motion and strain play important roles in vascular remodeling and may be important in the pathogenesis of vascular disease. In vivo observations of circumferentially nonuniform wall motion in the human aorta suggest that nonuniform strain may contribute to the localization of vascular pathology. A velocity-based method to investigate circumferential strain variations was previously developed and validated in vitro; the current study was undertaken to determine whether accurate displacement and strain fields can be calculated from velocity data acquired in vivo. Wall velocities in the porcine thoracic aorta were quantified with PC-MRI and an implanted coil and were then time-integrated to compute wall displacement trajectories and cyclic strain. Displacement trajectories were consistent with observed aortic wall motion and with the displacements of markers in the aortic wall. The mean difference between velocity-based and marker-based trajectory points was 0.1 mm, relative to an average pixel size of 0.4 mm. Propagation of error analyses based on the precision of the computed displacements were used to demonstrate that 10% strain results in a standard deviation of 3.6%. This study demonstrates that it is feasible to accurately quantify strain from low wall velocities in vivo and that the porcine thoracic aorta does not deform uniformly.

Algorithms↗
PubMed2004

Steady-state free precession MR imaging: improved myocardial tag persistence and signal-to-noise ratio for analysis of myocardial motion.

Tagging with balanced steady-state free-precession (SSFP) magnetic resonance (MR) imaging by using a steady-state storage scheme for myocardial motion analysis was evaluated. Signal-to-noise ratio (SNR), blood-tissue contrast, and tag persistence in volunteers and phantoms showed improved performance of SSFP imaging with tagging compared with that of radiofrequency spoiled gradient-echo (SPGR) MR imaging with tagging. Choice of flip angle with SSFP imaging involved a trade-off among SNR, blood-tissue contrast, and tag persistence. Increased SNR and tag persistence can be achieved simultaneously with SSFP imaging compared with SPGR tagging methods. As a result, the proposed technique may be useful for analysis of diastolic ventricular function.

Adult↗
PubMed2003

Time-resolved three-dimensional phase-contrast MRI.

PURPOSE: To demonstrate the feasibility of a four-dimensional phase contrast (PC) technique that permits spatial and temporal coverage of an entire three-dimensional volume, to quantitatively validate its accuracy against an established time resolved two-dimensional PC technique to explore advantages of the approach with regard to the four-dimensional nature of the data. MATERIALS AND METHODS: Time-resolved, three-dimensional anatomical images were generated simultaneously with registered three-directional velocity vector fields. Improvements compared to prior methods include retrospectively gated and respiratory compensated image acquisition, interleaved flow encoding with freely selectable velocity encoding (venc) along each spatial direction, and flexible trade-off between temporal resolution and total acquisition time. RESULTS: The implementation was validated against established two-dimensional PC techniques using a well-defined phantom, and successfully applied in volunteer and patient examinations. Human studies were performed after contrast administration in order to compensate for loss of in-flow enhancement in the four-dimensional approach. CONCLUSION: Advantages of the four-dimensional approach include the complete spatial and temporal coverage of the cardiovascular region of interest and the ability to obtain high spatial resolution in all three dimensions with higher signal-to-noise ratio compared to two-dimensional methods at the same resolution. In addition, the four-dimensional nature of the data offers a variety of image processing options, such as magnitude and velocity multi-planar reformation, three-directional vector field plots, and velocity profiles mapped onto selected planes of interest.

Contrast Media↗
PubMed2003

Dynamic exercise imaging with an MR-compatible stationary cycle within the general electric open magnet.

Many cases of muscular ischemia do not manifest without increased metabolic demand. Hence, diagnosis of intermittent claudication often requires inducing physiologic challenge, such as by exercise. Cine phase-contrast MRI can concurrently acquire cross-sectional vascular anatomy and through-plane blood velocities, enabling blood flow rate quantification. An MR-compatible stationary cycle was designed, constructed, and tested for flow quantification in large arteries during lower-limb exercise in a General Electric Signa SP 0.5 T open magnet. The cycle demonstrated smooth cycling during image acquisition, has freewheeling capability, is adjustable for subject size and strength, and can quantify workload. A healthy 59-year-old male was imaged at the supraceliac and infrarenal levels of the abdominal aorta at rest and during exercise. An exercise workload of 47.9 W was achieved. His heart rate increased from 52 to 78 bpm, supraceliac flow increased from 1.7 to 3.7 L/min, and infrarenal flow increased from 0.4 to 3.2 L/min from rest to exercise.

Aorta, Abdominal↗