Evaluation of the intratumoral vasculature of hepatocellular carcinoma by power Doppler sonography: advantages and disadvantages versus conventional color Doppler sonography

Background: To determine whether a difference exists in the relative ability of power Doppler sonography and conventional color Doppler sonography to detect the intratumoral vasculature of hepatocellular carcinoma based on lesion size and location. Methods: Sixty patients with 88 hepatocellular carcinoma lesions that showed tumor staining on angiography and were enhanced on dynamic computed tomography were evaluated. Power Doppler sonography and color Doppler sonography were used to detect the intratumoral vasculature, and their sensitivity to blood flow was evaluated. Results: Power Doppler sonography showed a superior detection rate for lesions smaller than 2 cm and located 4–8 cm from the abdominal surface in the right hepatic lobe as compared with color Doppler sonography (p < 0.01). Neither power Doppler sonography nor color Doppler sonography depicted the intratumoral vasculature of lesions located more than 8 cm from the abdominal surface (n = 14). Both color Doppler imagings exhibited a low detection rate for lesions in the left hepatic lobe (n = 31, p < 0.01). Conclusions: Power Doppler sonography should be applied in the evaluation of small or intermediate depth lesions because it is more sensitive to these lesions than color Doppler sonography, but it is not useful for left lobe and deep lesions. Received: 31 March 1999/Accepted: 14 July 1999     

Meal Ingestion and Hemodynamic Interactions Regarding Renal Blood Flow on Duplex Sonography: Potential Diagnostic Implications

Splanchnic blood flow changes dramatically after meal ingestion. The present study evaluated physiologic interactions between meal ingestion and hemodynamics with respect to renal blood flow on duplex sonography, assessing the possible influence on Doppler parameters used as diagnostic criteria for renal artery stenosis. Subjects comprised 26 healthy young men (mean age: 22 ± 2 y). Sonographic measurements were made shortly after breakfast and every 1 h thereafter and were compared with values measured before the meal. Peak systolic velocity in the renal artery was elevated post-prandially, peaking at 1 h (90 ± 12 cm/s), compared with pre-prandially (73 ± 10 cm/s, p < 0.01). Similarly, acceleration time at the intra-renal segmental artery shortened to a minimum at 1 h (45 ± 5 ms) compared with baseline (51 ± 6 ms, p < 0.01). The present study indicates that renal blood flow is altered for a few hours after meal ingestion. Attention should be paid to the interpretation of data measured after meals on duplex sonography for diagnosis of renal artery stenosis.     

Effect of enteral versus parenteral feeding on hepatic blood flow and steady state propofol pharmacokinetics in ICU patients

Objective: The main objective of this study was to evaluate the effect of switching from parenteral to enteral feeding on liver blood flow and propofol steady-state blood concentrations in patients in the intensive care unit (ICU). Design and patients: Steady-state blood concentrations of propofol were measured in eight ICU patients before (on days D –3, D –2, and D –1) and after (on days D + 1, D + 2, and D + 3) switching from parenteral to enteral feeding (on day D0). All patients received a continuous intravenous infusion of propofol (4.5 mg · kg^–1· h^–1) from several days before the start of the study, continuing throughout the experimental period. Hepatic blood flow was estimated by measuring steady-state D-sorbitol hepatic clearance. Results: Hepatic blood flow was high and was not affected by switching from parenteral to enteral feeding: 33 ± 8 ml · min^–1· kg^–1 (mean ± SD) and 33 ± 10 ml · min^–1· kg^–1 on D-3 and D –1, respectively, as compared to 37 ± 11 ml · min^–1· kg^–1 and 34 ± 8 ml · min^–1· kg^–1 on days D + l and D + 3, respectively. Systemic clearance of propofol was much higher than liver blood flow with average values on the six observation days ranging from 74.0 to 81.2 ml · min^–1· kg^–1 and was not affected by switching from parenteral to enteral feeding. Conclusions: Liver blood flow and systemic clearance of propofol were not affected by switching from parenteral to enteral feeding in the eight ICU patients studied. Extrahepatic clearance accounted for at least two thirds of the overall systemic clearance of propofol. Received: 18 July 1997 Accepted: 1 April 1998     

Global cerebral blood flow and CPP after severe head injury: a xenon-CT study

Objective To evaluate the association between global cerebral blood flow and different cerebral perfusion pressure ranges in severe head injury. Design A retrospective study Setting Neurosurgical and trauma patients in an intensive care unit in a regional hospital. Patients and participants Out of a series of 237 consecutive patients with severe head injuries (GCS ≤ 8), 162 were submitted to ICP monitoring and 89 of them underwent 180 xenon-CT studies and cerebral perfusion pressure (CPP) measurement. The xenon-CT studies did not include any unsalvageable patients nor any mistakenly diagnosed as severe on entry. Interventions None. Measurements and results Most (95.6%) of xenon-CT studies were obtained with CPP values within the 50–90 mmHg range. Perfusion data were grouped according to CPP values: (1) below 50 mmHg, (2) 50–60 mmHg, (3) 60–70 mmHg, (4) above 70 mmHg. Global cerebral blood flow did not differ among the groups (p = 0.49). No differences in physiological variables were found among the CPP groups, except for intracranial pressure, higher in the group with CPP below 50 mmHg, and mean arterial pressure, higher in the CPP above 70 mmHg group (p < 0.0001). No differences were found for cerebral metabolic rate of oxygen and lactate. Conclusions There was little correlation between CPP values and global cerebral blood flow levels in our selected patients, probably because pressure autoregulation was preserved. Global metabolism measurements were constant within the groups, suggesting that in patients with controlled physiological variables an interplay between cerebral blood flow and metabolism might be more relevant than the relationship between CPP and cerebral blood flow.     

Mesenteric cyst: sonographic findings

Background: Mesenteric cyst (MC) is a relatively rare disease, and its sonographic characteristics have not been sufficiently analyzed. Methods: We studied the sonographic findings of eight patients with MC, with attention paid to its size, shape, internal echoes, and especially the presence or absence of lateral shadowing and the mode of back echoes. In four cases, the sound velocity and acoustic impedance of cystic fluid were also measured. The mode of blood flow was evaluated by color Doppler sonography. Results: Six cases showed an oval or comma-shaped mass. Internal echoes were present in six cases, and two of them showed a pseudosolid pattern. In these cases, M-mode sonography confirmed the movement of these internal echoes. Only one case showed a posterior echo enhancement, and no case showed lateral shadowing. Sound velocity measured in four cases was 1515–1537 m/s, with an acoustic impedance of 1.550–1.576 kg/m²/s. No blood flow signals were obtained from the lesion. Conclusion: MC exhibits so many patterns on ultrasound that we should consider the possibility of MC when encountering an avascular oval mesenteric mass. Received: 30 August 1999/Accepted: 6 October 1999     

Comparison of angiography, duplex sonography and intravascular ultrasound for the graduation of femoropopliteal stenoses before and after balloon angioplasty

The graduation of femoropopliteal stenoses by either digital subtraction angiography (DSA) or duplex sonography remains challenging, particularly after percutaneous transluminal angioplasty (PTA). More accurate assessment of stenosis might be achieved with intravascular ultrasound (IVUS). We investigated the relationship between DSA, IVUS and duplex before and after 32 femoropopliteal PTAs. Over the whole range of stenoses, peak systolic velocity (PSV) and peak velocity ratio (PVR) correlated better with DSA-stenosis (R(2) = .72 and 0.74, respectively, p < 0.01) than with IVUS-stenosis (R(2) = 0.58 and 0.50, p < 0.01). Within the subgroup of preinterventional (51 to 99%) stenoses, PVR was significantly correlated only with DSA-stenosis (R(2) = 0.60, p < 0.01). Severe dissection after PTA was associated with a disproportionate rise in PSV and large discrepancies between IVUS and DSA. Unexpectedly, our data show that intrastenotic flow acceleration assessed by duplex sonography correlates better with DSA- than with IVUS-stenosis. The concordance between duplex sonography, DSA and IVUS was particularly weak in postinterventional measurements, casting some doubt on the reliability of these methods for the assessment of residual stenosis after femoropopliteal PTA.     

Color duplex sonography of occlusion of the common carotid artery with reversed flow in the extracranial internal carotid artery

In a small percentage of cases with an occluded common carotid artery (CCA), the patency of the arteries beyond the carotid bulb is preserved. Color duplex sonography is useful for assessing blood flow in these vessels. We present a case of retrograde flow in an internal carotid artery (ICA) with an occluded ipsilateral CCA identified using color duplex sonography in a 70-year-old man with diabetes and known atherosclerotic disease. Color duplex sonography revealed that the right CCA was totally occluded near its origin and that flow was re-established at the bulb. Flow in the right ICA was directed cephalad, with a low-frequency, damped waveform; flow in the right external carotid artery (ECA) was bidirectional, with increased reversed diastolic flow. Extensive atherosclerotic lesions were also found in the left side. Endarterectomy of the left carotid bifurcation was performed. Follow-up color duplex sonography 3 months later revealed a small increase of stenosis in the left CCA and mild stenosis in the left ICA. The right CCA remained occluded, but reversed flow with a high-resistance flow pattern was seen in the ipsilateral ICA that supplied the ECA, which had cephalad-directed flow.     

The effect of dobutamine infusion on splanchnic blood flow and oxygen transport in patients with acute pancreatitis

Objectives: To measure the blood flow distribution and oxygen transport in pancreatitis and to evaluate the regional effects of increased systemic blood flow. Design: Nonrandomized controlled trial. Setting: A general intensive care unit in a tertiary care center. Patients: 10 patients with pancreatitis requiring mechanical ventilation were studied after fluid resuscitation, and for the response to dobutamine, the patients served as their own controls. For the baseline, 11 patients scheduled for elective abdominal surgery served as a control group. Interventions: Systemic and regional hemodynamics were measured after fluid resuscitation to predefined hemodynamic endpoints. In patients with pancreatitis, the measurement was repeated after cardiac output had been increased by at least 25 % by dobutamine. Measurements and results: Hepatosplanchnic blood flow was estimated using regional catheterization and the dye dilution method. In patients with pancreatitis, the cardiac index did not differ from that of the control group (3.9 ± 0.8 vs 4.1 ± 0.7 l · min^–1· m^–2;NS). Accordingly, there was no difference in the splanchnic blood flow (1.1 ± 0.4 vs 1.2 ± 0.5 l · min^–1· m^–2;NS). Systemic and splanchnic oxygen consumption was increased in patients with pancreatitis (179 ± 25 vs 147 ± 27 ml · min^–1· m^–2, p < 0.05 and 68 ± 15 vs 49 ± 19 ml · min^–1· m^–2, p < 0.05), and systemic and splanchnic oxygen extraction was higher (0.34 ± 0.08 vs23 ± 0.05, p < 0.01 and 0.46 ± 0.18 vs 0.28 ± 0.08, p < 0.05, respectively). Dobutamine had inconsistent effects on splanchnic blood flow: in individual patients, splanchnic blood flow even decreased substantially. Conclusions: In severe pancreatitis, oxygen consumption is increased in the splanchnic region; increased splanchnic oxygen demand is not always met by adequately increased blood flow. Increasing the systemic blood flow with dobutamine does not improve perfusion in the splanchnic bed. Received: 24 September 1996 Accepted: 5 May 1997     

Effects of pulmonary blood volume on vascular reactivity in the lung

Objective: Pulmonary flow resistance is mainly determined by vessel calibres, resulting from the interaction of volume-passive distension and active vasomotion. However, quantitative information on the interplay between these counteracting forces in the lung is lacking. Therefore, we aimed at quantifying (1) the effects of vasomotor tone on pulmonary blood volume (Qp) and (2) the influence of Qp on vascular reactivity. Design: Experimental study in isolated zone III rabbit lungs perfused with autologous blood. Setting: Research department of experimental anaesthesiology. Interventions: Stepwise changes of pulmonary blood flow (Q˙= 0 – 200 ml · min^–1) and Qp (10–30 ml) were applied independently of each other during normoxia (control), hypoxic vasoconstriction (3 % O₂) and vasodilation by papaverine (10^–4 M). Measurements: The arteriovenous pressure gradient (ΔP) was calculated as the difference between the pressures in the pulmonary artery and the left atrium. Qp was continuously measured as reciprocal volume changes in the blood reservoir. Results: Vasomotor interventions did not alter Qp despite substantial changes in pulmonary artery pressure. Vasoconstriction and decreasing Qp shifted the pressure/flow curves to greater ΔP, whereas vasodilation, as well as increasing Qp, had the opposite effect. Analysis of the pressure/flow relations by the equation ΔP = K · Q˙^m revealed that both parameters (K and m) were functions of Qp but only K was affected by vasoconstriction and vasodilation. K, an indicator of flow resistance, decreased hyperbolically to one-sixth and approached each other as Qp was tripled, whereas m increased only 1.5-fold (0.5–0.8). The factorial changes of K from constricted to dilated states varied from 2 to 2.9 and attained a maximum at Qp = 20 ml. Conclusions: Pulmonary blood volume, although not affected by vasomotor interventions, attenuates vascular reactivity in the lung. Received: 28 March 1999 Accepted: 1 October 1999     

Optical Pretargeting of Tumor with Fluorescent MORF Oligomers

Objective Pretargeting with radioactivity has significantly improved tumor to normal tissue radioactivity ratios over conventional antibody imaging in both animal studies and clinical trials. This laboratory is investigating DNA analogues such as phosphorodiamidate morpholinos (MORFs) for pretargeting using technetium-99m (^99mTc) for detection. However, the unique properties of fluorescence activation and quenching combined with oligomers with their unique properties of hybridization may be particularly useful when used together for pretargeting with optical detection. The use of linear fluorophore-conjugated oligomer duplexes have been little used in animals, and to our knowledge, have not previously been considered for pretargeting applications. Methods A MORF/cDNA pair was selected such that when hybridized, the fluorescence of the Cy5.5-conjugated 25 mer MORF (Cy5.5–MORF25) is inhibited with a BHQ3-conjugated 18 mer complementary DNA (BHQ3–cDNA18). The short BHQ3–cDNA18 was selected to dissociate in the presence of a long cMORF25 in the pretargeted tumor, thus releasing the inhibitor from the Cy5.5 emitter. In this manner, the Cy5.5 fluorescence will be inhibited everywhere but in the target. The dissociation was first examined in vitro by adding the duplex to the cMORF25 both in solution and immobilized on polystyrene microspheres and by surface plasmon resonance (SPR). Thereafter, biotinylated cMORF25 immobilized on streptavidin polystyrene microspheres were administered intramuscularly in one thigh of hairless SKH-1 mice as target while an identical weight of the identical microspheres but without the cMORF25 was administered in the contralateral thigh as control. The animals then received IV the Cy5.5–MORF25/BHQ3–cDNA18 duplex or equal molar dosage of single-chain Cy5.5–MORF25 and were imaged. Results The SPR studies showed that the immobilized cDNA18 rapidly captured the flowing MORF25 to provide a duplex with a slow dissociation rate constant. Furthermore, when cMORF25 was next allowed to flow over the now immobilized duplex, the cDNA18 was unable to prevent dissociation of the heteroduplex and the formation and release of the cMORF25-MORF25 homoduplex. Images of animals obtained soon after receiving the Cy5.5–MORF25 singlet showed intense whole body fluorescence obscuring the target thigh. However, only 5 minutes after receiving the Cy5.5–MORF25/BHQ3–cDNA18 duplex, the target thigh was clearly visible along with only the kidneys. Conclusions This first study of optical pretargeting provides a proof of concept that oligomer pretargeting found to be useful with radioactivity detection is applicable with fluorescent detection as well. In addition, our results demonstrate that by using linear oligomers for optical pretargeting, chain lengths (and base sequences) may be manipulated to provide duplexes with stabilities and fluorescence inhibition optimized for pretargeting and other in vivo applications of optical imaging.     

Characterization of solid liver lesions with color and pulsed Doppler imaging

Background: To assess the usefulness of color Doppler and duplex sonography in the characterization of solid liver lesions. Methods: We performed color Doppler and duplex sonography on 106 solid hepatic lesions. With color Doppler, we evaluated the aspect and distribution of tumoral vessels. The pulsed Doppler parameters considered were only those showing the highest systolic peak velocity values. Results: Intratumoral color and pulsed Doppler signals were obtained in 81% (59/73) of malignant tumors (p < 0.0001) but only in 18% (6/33) of benign tumors. Ninety-six percent (45/47) of the lesions with arterial intratumoral and peritumoral signals were malignant, whereas 4% were benign (p < 0.0001). Only eight (11%) malignant lesions had intratumoral venous signal vis-a-vis 23 (70%) benign. Twelve cases showing intratumoral venous Doppler signal as a single finding were benign. No statistically significant differences were observed in the quantitative parameters recorded by pulsed Doppler (Student t test, p < 0.05), there having been a clear overlapping in the values obtained in benign and malignant lesions. Conclusions: (a) The type of signal (arterial or venous) and its distribution detected by color and pulsed Doppler is more helpful than the assessment of the spectral quantitative parameters obtained by pulsed Doppler. (b) The presence of intratumoral venous flow remarkably suggests benignancy. (c) The presence of both intra- and peritumoral arterial flow in the same lesion strongly suggests malignancy. Received: 3 January 1997/Revision accepted: 17 December 1997     

Accuracy and reproducibility of long-term implanted transit-time ultrasound flow probes in dogs

Objective: To assess the accuracy and reproducibility of long-term implanted ultrasound transit-time flow probes for measuring cardiac output. Design: Prospective animal study. Settings: Animal research laboratory in a university department. Animals: Eleven anaesthetised dogs, 24–34 kg. Measurements and results: Flow probes (16–24 mm S-series, Transonic) were implanted around the pulmonary artery for a mean duration of 22 months (range 6–47 months). Comparisons (n = 147) were made between cardiac output thus obtained and that measured by the direct Fick principle using oxygen uptake (Deltatrac II Metabolic Monitor) and the arterial to mixed venous oxygen content difference measured by a galvanic cell (Lex-O₂-Con-TL). Measurements were made either during baseline conditions or during pharmacologically altered cardiac output (range 22–180 ml · kg^–1· min^–1). Regardless of the intervention, the two methods yielded the same results in half of the dogs. In the others, however, cardiac output was underestimated by the flow probes by up to 38 % (probably because of non-perpendicular position of the probe towards the vessel). This difference was constant for the whole range of cardiac output studied and remained constant over the entire observation period for each individual dog, so that a correction factor was used. Thereafter, the mean difference between the two methods was –1.1 ml · kg^–1· min^–1 with a precision (SD) of 14.2 ml · kg^–1· min^–1 for all experiments. Conclusions: After in vivo calibration, ultrasound transit-time flow probes measure cardiac output precisely for several years, regardless of the intervention. Received: 1 October 1999 Final revision received: 6 January 2000 Accepted: 4 February 2000     

Day-to-Day Test–Retest Variability of CBF,CMRO<Subscript>2</Subscript>, and OEF Measurements Using Dynamic <Superscript>15</Superscript>O PET Studies

Purpose  

We assessed test–retest variability of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen (CMRO₂), and oxygen extraction fraction (OEF) measurements derived from dynamic ¹⁵O positron emission tomography (PET) scans.     

Determination of functional residual capacity (FRC) by multibreath nitrogen washout in a lung model and in mechanically ventilated patients

Objective: Validation of an open-circuit multibreath nitrogen washout technique (MBNW) for measurement of functional residual capacity (FRC). The accuracy of FRC measurement with and without continuous viscosity correction of mass spectrometer delay time (T_D) relative to gas flow signal and the influence of baseline FIO₂ was investigated. Design: Laboratory study and measurements in mechanically ventilated patients. Setting: Experimental laboratory and anesthesiological intensive care unit of a university hospital. Patients: 16 postoperative patients with normal pulmonary function (NORM), 8 patients with acute lung injury (ALI) and 6 patients with chronic obstructive pulmonary disease (COPD) were included. Interventions: Change of FIO₂ from baseline to 1.0. Measurements and main results: FRC was determined by MBNW using continuous viscosity correction of T_D (T_Ddyn), a constant T_D based on the viscosity of a calibration gas mixture (T_D0) and a constant T_D referring to the mean viscosity between onset and end of MBNW (T_Dmean). Using T_Ddyn, the mean deviation between 15 measurements of three different lung model FRCs (FRC_measured) and absolute volumes (FRC_model) was 0.2 %. For baseline FIO₂ ranging from 0.21 to 0.8, the mean deviation between FRC_measured and FRC_model was −0.8 %. However, depending on baseline FIO₂, the calculation of FRC using T_Dmean and T_D0 increased the mean deviation between FRC_measured and FRC_model to 2–4 % and 8–12 %, respectively. In patients (n = 30) the average repeatability coefficient was 6.0 %. FRC determinations with T_Dmean and T_D0 were 0.8–13.3 % and 4.2–23.9 % (median 2.7 % and 8.7 %) smaller than those calculated with T_Ddyn. Conclusion: A dynamic viscosity correction of T_D improves the accuracy of FRC determinations by MBNW considerably, when gas concentrations are measured in a sidestream. If dynamic T_D correction cannot be performed, the use of constant T_Dmean might be suitable. However, in patient measurements this can cause an FRC underestimation of up to 13 %. Received: 29 August 1997 Accepted: 11 March 1998     

Impact of alcohol septal ablation on left anterior descending coronary artery blood flow in hypertrophic obstructive cardiomyopathy

Objectives The aim of this study was to evaluate the effects of alcohol septal ablation (ASA) on coronary blood flow in symptomatic hypertrophic obstructive cardiomyopathy (HOCM) using cardiac MR (CMR) coronary flow measurements. Background CMR flow mapping enables quantification of coronary blood flow in a noninvasive way. Both left ventricular outflow tract (LVOT) gradient reduction and myocardial scarring after ASA are expected to influence left anterior descending (LAD) coronary blood flow. Methods Cine, contrast-enhanced (CE) imaging and breath-hold CMR phase contrast velocity mapping were performed at baseline and 1 and 6 months after ASA in seven patients. Changes of coronary blood flow were related to left ventricular (LV) mass reduction, enzyme release, volume of ethanol administered, LVOT gradient reduction, and LV rate pressure product (LVRPP). Results A significant mass reduction was observed both in the target septal myocardium and in the total myocardium (both P < 0.01). Mean myocardial infarct size was 23 ± 12 g (range 7.3–41.6 g). LVRPP decreased from 13,268 ± 2,212 to 10,685 ± 3,918 at 1 month (P = 0.05) and 9,483 ± 2,496 mmHg beats/min at 6 months’ follow-up (P < 0.01). LAD coronary blood flow decreased from 100 ± 37 ml/min at baseline to 84 ± 54 ml/min (P = 0.09) at 1 month and 67 ± 33 ml/min at 6 months follow-up (P < 0.01). A significant correlation was found between the change in LVRPP and LAD coronary flow at 1 month follow-up (r = 0.83, P = 0.02). CE-infarct size tended to modulate the blood flow changes over time (P = 0.12); no correlation was observed between enzyme release, volume of ethanol or both septal and total mass reduction and coronary blood flow. Conclusion The reduction in coronary blood flow is primarily associated with diminished LV loading conditions, whereas the induction of metabolically inactive myocardial scar tissue by ASA did not significantly influence the changes in coronary blood flow.     

Assessment of the extension and the inflammatory activity in Crohn’s disease: comparison of ultrasound and MRI

Objective  The purpose of this prospective study was twofold: to examine the efficacy of MRI and sonography in the assessment of Crohn’s disease (CD) activity in comparison with clinical scoring and biologic tests and to compare both techniques in the evaluation of extension and transmural complications. Material and methods  Thirty patients with histologically proven Crohn’s disease were prospectively examined the same day first with sonography and after MRI. Sonographic exam included evaluation of bowel wall thickness, vascularity pattern, and perienteric changes. Thirty minutes prior to MRI imaging, patients were given 250 mL of dilute sodium phosphate solution and additional 750 mL of water orally. MRI images evaluation included bowel wall thickening, bowel wall enhancement, and perienteric changes. The gastrointestinal tract was divided into five segments. Findings and extension of the both techniques were verified by means of barium studies, surgery, or/and colonoscopy. The sonographic and MR findings were compared with clinical and laboratory data. Results  About 53 of 119 (45%) bowel segments showed pathological changes in gold standard tests. Sonography was superior to MRI in the localization of affected bowel segments (sensitivity: US 91%; MRI 83%; intertechniques agreement, kappa: 0.905) and in recognizing transmural complications (sensitivity: US 80%; MRI 72%), although significant differences were not found (p > 0.05). A statistically significant correlation between color Doppler flow and MR bowel wall enhancement (segment-by-segment analysis and per patient analysis; p > 0.5), and between perienteric changes in both techniques (p > 0.5) were found. Wall thickness measured on sonography was significantly greater in the group of patients with clinical activity (p = 0.023) or with clinical-biologic activity (p = 0.024). Grades of hyperemia and MR contrast enhancement of patients with clinical–biologic activity was higher than in patients without clinical–biologic activity (p = 0.019; p = 0.023). Conclusion  In summary, both ultrasound and MRI are sensitive to localize the affected bowel segments and to detect transmural complications in patients with Crohn’s disease. A significant correlation between color Doppler flow and bowel wall enhancement on MRI was found. Sonographic wall thickness, color Doppler flow, and bowel wall enhancement on MRI are related with clinical or biologic activity.     

A comparison of video and digital data in the assessment of myocardial perfusion abnormalities by myocardial contrast echocardiography

Objective: The objective of the present study was to compare the digital and video data of myocardial contrast echocardiography (MCE) to assess altered myocardial blood flow produced by graded coronary stenoses. Methods: Three grades of left anterior descending (LAD) coronary artery stenosis and occlusion were created in eight open-chest canine models. MCE was performed with BR1 infusion by harmonic power Doppler with ECG gated intermittent triggered imaging at pulsing intervals ranging from 1:1 to 1:10. For images that were recorded simultaneously on both a videotape (video data) and an optical disk (digital data), myocardial signal intensity in the LAD region was plotted vs. pulsing intervals and was fitted to an exponential function:y=A(1 − e^−bt ), where A is the peak plateau signal intensity, and b is the rate of signal intensity rise for quantification of myocardial blood flow. Results: Both values for A and b progressively decreased with a greater level of stenosis. The correlation of A with myocardial blood flow (determined by use of fluorescent microspheres) was weak with digital data (r= 0.38, p= 0.037), and was insignificant with video data (r= 0.16, p= 0.38). The correlation of b with microsphere-derived myocardial blood flow was better than that of A with both video and digital data, and was similar between the two kinds of data (video:r= 0.69, p < 0.0001; digital:r= 0.68, p < 0.0001). Conclusions: Video and digital MCE data are equivalent in their ability to quantify altered myocardial blood flow produced by graded coronary stenoses.     

The mechanics of breathing in children with acute severe croup

Rationale The assessment of the severity of croup and response to therapy has remained a clinical one. Despite recognition of the importance of a reproducible and easily applicable method for objectively measuring severity, currently, no such technique exists. Objectives We postulated that measurements of air flow and intrathoracic pressure changes in patients with severe croup would provide detailed information about the mechanics of breathing and the potential for the development of continuous bedside methods for objective monitoring of upper airway obstruction. Methods Twenty out of 21 eligible infants and children with severe upper airway obstruction from croup, and 5 control participants, were studied under light sedation utilizing face masks and nasogastric feeding tubes for flow and esophageal pressure measurements. Measurements and main results Children with croup had lower tidal volumes, but breathed faster, thus maintaining similar minute volumes to the controls. During inspiration, all but 2 croup patients (but no controls) displayed flow limitation. Area within the flow–volume curve was significantly decreased and minute ventilation for effort expended was nearly 4.5 times higher in croup patients than in controls. Peak-to-trough pleural pressure swings, pressure–rate product and pressure–time integral were also significantly higher than in controls (p < 0.001) and returned to the normal range in the 9 patients who were subsequently intubated (p < 0.001). Conclusions Patients with severe croup maintain minute ventilation by means of huge increases in intrathoracic pressure changes. Inspiratory flow limitation is present. In future outcome studies, measurements of respiratory function that do not include intrathoracic pressure changes are unlikely to be effective measures of the severity of croup. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Declaration: The authors are neither supported by, nor maintain any financial interest in, any commercial activity associated with the topic of this article.     

Peripherally inserted central catheters are equivalent to centrally inserted catheters in intensive care unit patients for central venous pressure monitoring

To determine the equivalency of pressure measurements from peripherally inserted central catheters (PICCs) versus centrally inserted central venous catheters (CVCs) in vitro as well as in vivo. The in vitro study was performed in a clinical laboratory. Static pressure measurements from PICCs and CVCs were obtained in vitro over a physiologic range of 5–25 mmHg. Triple and dual lumen PICCs were directly compared to CVC controls. Dynamic pressure waveforms were recorded to simulate physiologic intravascular pressure variation. The in vivo study was executed in the medical intensive care unit (MICU) of a tertiary-level academic medical center. Data was collected from ten adult patients with both a PICC and a CVC in place for on-going clinical care. Measurements of central venous pressure (CVP) were recorded simultaneously from PICCs and CVCs. Duplicate measurements were taken after a stable waveform was recorded. For the in vitro study, a total of 540 pressure measurements were recorded. The average bias determined by Bland–Altman plot was 0 mmHg for the 5Fr PICC and 0.071 mmHg for the 6Fr PICC. The correlation coefficient for both catheters was 1.0 (P < 0.001). Dynamic pressure waveforms revealed equivalent amplitude. During the in vivo trial, 70 CVP measurements were collected. The paired CVP measurements were found to be highly reliable across subjects (r = 0.99, P < 0.0001). No significance in the average difference in CVP measurement (PICC–CVC) was determined by the Wilcoxon Signed Rank test (S = 1, P = 0.93). In conclusion, PICCs are equivalent to CVCs when measuring static and dynamic pressure in vitro and CVP in ICU patients.     

Does the Use of Automated Fetal Biometry Improve Clinical Work Flow Efficiency?

This study was designed to compare the work flow efficiency of manual measurements of 5 fetal parameters with a novel technique that automatically measures these parameters from 2‐dimensional sonograms. This prospective study included 200 singleton pregnancies between 15 and 40 weeks' gestation. Patients were randomly allocated to either manual (n = 100) or automatic (n = 100) fetal biometry. The automatic measurement was performed using a commercially available software application. A digital video recorder captured all on‐screen activity associated with the sonographic examination. The examination time and number of steps required to obtain fetal measurements were compared between manual and automatic methods. The mean time required to obtain the biometric measurements was significantly shorter using the automated technique than the manual approach (P < .001 for all comparisons). Similarly, the mean number of steps required to perform these measurements was significantly fewer with automatic measurements compared to the manual technique (P < .001). In summary, automated biometry reduced the examination time required for standard fetal measurements. This approach may improve work flow efficiency in busy obstetric sonography practices.