Evaluation of gallbladder volume and emptying with a novel three-dimensional ultrasound system: Comparison with the sum-of-cylinders and the ellipsoid methods

To overcome the geometrical limitations of current methods to calculate gallbladder volume from two-dimensional sonographic images, we evaluated the accuracy and precision of a novel three-dimensional ultrasound system (3D). In vitro accuracy of 3D volumetry (10 mL to 55 mL) was 98.1 ± 7.1% (mean ± SD) with a mean difference of 0.7 mL between the measured and the true volume (p < 0.003). Compared with the sum-of-cylinders (SC) and the ellipsoid (EL) methods, 3D was characterized by a significantly smaller systematic bias and closer limits of agreement with the true volume. The variation coefficient was smallest with 3D (2.4%, p < 0.02) and largest with EL (4.2%). In vivo, gallbladder volumes were on average 1.4 mL (9%) smaller with 3D than with SC (p < 0.0001) and 2.4 mL (14%) larger with EL than with SC (p < 0.0001). 3D ultrasonography accurately measures gallbladder volume and emptying. © 1996 John Wiley & Sons, Inc.     

Quantification of left atrial volume and phasic function using cardiovascular magnetic resonance imaging—comparison of biplane area-length method and Simpson's method

Left atrial (LA) enlargement and dysfunction are markers of chronic diastolic dysfunction and an important predictor of adverse cardiovascular and cerebrovascular outcomes. Accordingly, accurate quantification of left atrial volume (LAV) and function is needed. In routine clinical cardiovascular magnetic resonance (CMR) imaging the biplane area-length method (Bi-ALM) is frequently applied due to time-saving image acquisition and analysis. However, given the varying anatomy of the LA we hypothesized that the diagnostic accuracy of the Bi-ALM is not sufficient and that results would be different from a precise volumetric assessment of transversal multi-slice cine images using Simpson's method. Thirty one patients of the FIND-AF_RANDOMISED-study with status post acute cerebral ischemia (mean age 70.5?±?6.2 years) received CMR imaging at 3T. The study protocol included cine SSFP sequences in standard 2- and 4 CV and a stack of contiguous slices in transversal orientation. Total, passive and active LA emptying fractions were calculated from LA maximal volume, minimal volume and volume prior to atrial contraction. Intra- and inter-observer variability was assessed in ten patients. Significant differences were found for LA volume and phasic function. The Bi-ALM significantly underestimated LA volume and overestimated LA function in comparison to Simpson's method (Bi-ALM vs. Simpson's method: LAV_max: 80.18 vs. 98.80 ml; LAV_pre?ac: 61.09 vs. 80.41 ml; LAV_min: 36.85 vs. 52.66 ml; LAEF_Total: 55.17 vs. 47.85%; LAEF_Passive: 23.96 vs. 19.15%; LAEF_Booster: 40.87 vs. 35.64%). LA volumetric and functional parameters were reproducible on an intra- and inter-observer levels for both methods. Intra-observer agreement for LA function was better for Simpson's method (Bi-ALM vs. Simpson's method; ICC LAEF_Total: 0.84 vs. 0.96; ICC LAEF_Passive: 0.74 vs. 0.92; ICC LAEF_Booster: 0.86 vs. 0.89). The Bi-ALM is based on geometric assumptions that do not reflect the complex individual LA geometry. The assessment of transversal slices covering the left atrium with Simpson's method is feasible and might be more suitable for an accurate quantification of LA volume and phasic function.     

Volume estimation of small phantoms and rat kidneys using three-dimensional ultrasonography and a position sensor

To evaluate the accuracy of small volume estimation, both in vivo and in vitro, measurements with a three-dimensional (3D) ultrasound (US) system were carried out. A position sensor was used and the transmitting frequency was 10 MHz. Balloons with known volumes were scanned while rat kidneys were scanned in vivo and in vitro. The Archimedes' principle was used to estimate the true volume. For balloons, the 3D US system gave very good agreement with true volumes in the volume range 0.1 to 10.0 mL (r = 0.999, n = 45, mean difference +/- 2SD = 0.245 +/- 0.370 mL). For rat kidneys in vivo (volume range 0.6 to 2.7 mL) the method was less accurate (r = 0.800, n = 10, mean difference +/- 2SD = -0.288 +/- 0.676 mL). For rat kidneys in vitro (volume range 0.3 to 2.7 mL) the results showed good agreement (r = 0.981, n = 23, mean difference +/- 2SD = 0.039 +/- 0.254 mL). For balloons, kidneys in vivo and in vitro, the mean percentage error was 9.3 +/- 4.8%, -17.1 +/- 17.4%, and 4.6 +/- 11.5%, respectively. This method can estimate the volume of small phantoms and rat kidneys and opens new possibilities for volume measurements of small objects and the study of organ function in small animals. (E-mail ).     

Accuracy of real-time three-dimensional echocardiography for quantifying right ventricular volume: static and pulsatile flow studies in an anatomic in vitro model.

OBJECTIVE: The complex structural geometry of the right ventricle hinders accurate assessment of right ventricular volume and function on conventional two-dimensional echocardiography. We sought to evaluate the accuracy of real-time three-dimensional echocardiography for quantifying the volume of the right ventricle in an in vitro experimental study. METHODS: We developed 39 anatomically accurate latex phantoms of human and porcine right ventricles (range, 24-108 mL) for 39 static and 10 pulsatile models. Real-time three-dimensional scanning was performed with the models placed in a water bath and with a 3.5-MHz probe. In the dynamic models a pulsatile flow pump generated 2 different stroke volumes (29 and 64 mL/beat). Static chamber volumes and stroke volumes were verified by water displacement, which served as a reference standard. Three-dimensional echo right ventricle volumes were determined by tracing derived B- and C-scans, using the Simpson rule. RESULTS: Multiple regression analyses showed an excellent correlation between real-time three-dimensional echocardiographic determinations and the static volumes (B-scan, r = 0.99; C-scan, r = 0.98; P < .001), as well as stroke volumes in the dynamic model (B-scan, r = 0.90; C-scan, r = 0.86; P < .001). However, the C-scans tended to underestimate cavity and stroke volumes more than the B-scans (mean difference for static volume: B-scan, 1.4% +/- 9.8%; C-scan, -7.4% +/- 8.0%; P < .001; mean difference for stroke volumes: B-scan, 3.0% +/- 19.1%; C-scan, -2.5% +/- 20.9%; P < .001). CONCLUSIONS: Real-time three-dimensional echocardiography can accurately quantify right ventricle cavity volumes and stroke volumes without geometric assumptions.     

Normal splenic volumes estimated using three-dimensional ultrasonography.

The purposes of this study were to determine splenic volumes using three-dimensional ultrasonography and to compare these measurements with two-dimensional splenic indices. Fifty-two healthy volunteers were studied. Two-dimensional volume measurements were based on length, width, and thickness, and the splenic index was calculated using the standard prolated ellipsoid formula (length x width x thickness x 0.523). Three-dimensional volume planar measurements were obtained with a slice by slice technique by manually drawing a region of interest around the spleen from one end of the sweep to the opposite end. These measurements were recorded three times by two observers. In addition, in vitro determination of splenic volume was performed using three cadaveric human spleens in a water bath. No statistically significant interobserver or intraobserver variability was present for either two-dimensional or three dimensional ultrasonography. Three-dimensional sonographic estimations of planar splenic volumes and ellipsoid splenic volumes were consistently smaller than two-dimensional sonographic estimations of splenic volumes. Three-dimensional sonographic splenic volumes calculated in vitro using the planar method were accurate to within 2% of in vitro water displacement volumes. Three-dimensional ultrasonography is potentially superior to two-dimensional sonography for evaluation of irregularly shaped objects, such as the spleen, and can provide improved accuracy over that of traditional two-dimensional techniques.     

Beyond Simpson's Rule: Accounting for Orientation and Ellipticity Assumptions

Simpson's biplane rule (SBR) is considered the gold standard method for left ventricle (LV) volume quantification from echocardiography but relies on a summation-of-disks approach that makes assumptions about LV orientation and cross-sectional shape. We aim to identify key limiting factors in SBR and to develop a new robust standard for volume quantification. Three methods for computing LV volume were studied: (i) SBR, (ii) addition of a truncated basal cone (TBC) to SBR and (iii) a novel method of basal-oriented disks (BODs). Three retrospective cohorts representative of the young, adult healthy and heart failure populations were used to study the impact of anatomical variations in volume computations. Results reveal how basal slanting can cause over- and underestimation of volume, with errors by SBR and TBC >10 mL for slanting angles >6°. Only the BOD method correctly accounted for basal slanting, reducing relative volume errors by SBR from –2.23 ± 2.21% to –0.70 ± 1.91% in the adult population and similar qualitative performance in the other two cohorts. In conclusion, the summation of basal oriented disks, a novel interpretation of SBR, is a more accurate and precise method for estimating LV volume.     

Validation of volume and mass assessments for human fetal heart imaging by 4-dimensional spatiotemporal image correlation echocardiography: in vitro balloon model experiments.

OBJECTIVE: This study was designed to validate a slow-sweep real-time 4-dimensional (4D) spatiotemporal image correlation method for producing quantitatively accurate dynamic fetal heart images using an in vitro pulsatile balloon model and apparatus. METHODS: To model fetal heart chambers, asymmetric double-walled finger stalls (tips of surgical latex gloves) were used and attached to a laboratory-designed circuit that allowed calibrated changes in the inner balloon volume as well as an intermediate gel mass interposed between the 2 layers. The water-submerged model was attached to a small-volume pulsatile pump to produce phasic changes in volume within the inner balloon at a fixed rate. A sonography system with 4D spatiotemporal image correlation (STIC) capabilities was used for 3-dimensional (3D) and 4D data acquisition. Volume data were analyzed by customized radial summation techniques with 4D data analysis software and compared with known volumes and masses. RESULTS: Fifty-six individual volumes ranging from 2.5 to 10 mL were analyzed. Volume and mass measurements with 4D STIC were highly correlated (R2 > 0.90). The mean percentage error was better (<6%) for volumes exceeding 4 mL and was as low as 0.3% for 6-mL estimations. Measurements in the diastolic phase were the most accurate, followed by mass estimations equivalent to chamber walls. There was a wider range of percentage error in the lowest volumes tested (2.5 mL), which might have arisen from difficulties in spatial resolution or distortions from within the model apparatus itself. Resolution limitations of 4D technology in combination with extremely small volume targets may explain higher error rates at these small volumes. CONCLUSIONS: Four-dimensional STIC is an acceptably accurate method for volume and mass estimations in the ranges comparable with mid- and late-gestation fetal hearts. It is particularly accurate for diastolic estimations, for chamber wall mass measurements, and at volumes of greater than 2.5 mL. This study validates use of 4D STIC technology to overcome the limitations of nongated 3D technology for phasic and quantitative assessments in fetal echocardiography.     

Evaluation of platelet concentrates stored for 5 days with reduced plasma volume

BACKGROUND: Currently, platelet concentrates (PCs) are stored in a suspending plasma volume of 45 to 65 mL. Previous studies using second- generation containers indicated that PCs stored for 5 days at volumes less than 30 mL have reduced in vivo percentage recoveries as compared to PCs stored at volumes of 50 mL or more. STUDY DESIGN AND METHODS: This study has evaluated the effect of PC plasma volume on the maintenance of in vivo and in vitro platelet properties following 5 days of storage, with the purpose of establishing the minimum plasma volume in the range of 30 to 50 mL. Twenty paired studies were performed in which identical populations of platelets from the same donor (obtained by double manual apheresis) were stored in a normal volume (55-60 mL, control) and reduced volume (30-50 mL, test) of plasma. Comparison of in vivo viability between test and control PCs was performed after random radiolabeling of 1 unit with 51Cr and of the other with 111In, with simultaneous transfusion and with calculation of percentage recovery and the area below the survival curve (integral) as measures of viability. RESULTS: When test unit volumes were > or = 35 mL, essentially identical platelet survival curves and in vitro results were obtained for test and control. The integral and the percentage recovery for the test units were (mean, 95% confidence interval) 98.7 (96.3-101.0) and 99.0 percent (94.7-103.3) of those values in the control units, respectively. Test units with volume < or = 34 mL demonstrated reduced in vivo viability with integral and percentage recovery of 81.1 (68.9-93.3) and 80.4 (69.3-91.5), respectively, as compared to the control units. This loss was associated with increased metabolic activity (lactate production), which may suggest platelet activation due to the increased surface-to-PC volume ratio. CONCLUSION: These results show that the storage volume of PCs may be reduced from 50 to 60 mL to 35 to 40 mL without any significant decrease in in vivo or in vitro platelet quality.     

Renal Volume Estimation Using Freehand Ultrasound Scans: An Ex Vivo Demonstration

Renal volume has the potential to serve as a robust biomarker for tracking the onset and progression of renal diseases and also for quantifying renal function. We propose a method to estimate renal volumes using freehand ultrasound scans at the point of care. A conventional ultrasound probe was augmented with an Intel RealSense D435 i camera. Visual inertial simultaneous localization and mapping was used to localize the probe in free space. The acquired 2-D ultrasound images, segmented by trained clinicians, were combined with the estimated poses of the probe to yield accurate volumes. The method was tested on two ex vivo sheep kidneys embedded in gelatin phantoms. Four different scanning protocols were tested: transverse linear, transverse fan, longitudinal linear and longitudinal fan. The estimated renal volumes were compared with those obtained using the water displacement method, the ellipsoidal method and computed tomography imaging. The water displacement method yielded mean volumes of 66.00 and 66.20 mL for kidneys 1 and 2, respectively (ground truth). Freehand ultrasound scans produced mean volumes of 64.08 mL (2.90% error) and 65.25 mL (1.40% error); the ellipsoidal method yielded volumes of 57.49 mL (12.90% error) and 60.15 mL (9.13% error); and computed tomography yielded a volume of 63.00 mL (4.54% error).     

A novel technique using biplane cine magnetic resonance imaging to evaluate left ventricular volume in children

The purpose of the study is to determine the feasibility of a novel simplified technique using cine magnetic resonance imaging (MRI) to assess left ventricular (LV) volume and ejection fraction (EF) validated by comparison with biplane LV angiography. Previous MRI studies to assess LV volumes have used multiple axial planes, which are compromised by partial volume effects and are time consuming to acquire and analyze. Accordingly, we developed a simplified imaging approach using biplane cine MRI and imaging planes aligned with the intrinsic cardiac axes of the LV. We studied 20 children (aged 4 months to 10 years) with various heart diseases. The accuracy of cine MRI was compared with that of LV angiography in all patients. LV volumes were calculated using Simpson's rule algorithm, for both MRI and LV angiography. LV volumes determined from MRI were slightly underestimated but correlated reasonably well with angiographic volumes (LVEDV: Y = 0.88X + 1.58, r = 0.99, LVESV: Y = 0.73X + 1.03, r = 0.98). Most importantly, even in patients who had abnormal ventricular curvature such as in tetralogy of Fallot, MRI determined LV volumes correlated well with angiographic values. The MR study was completed within 35 min in all patients. In conclusion, simplified biplane cine MRI, using the intrinsic LV axis planes, permits noninvasive assessment of LV volumes in views comparable to standard angiographic projections and appears practical for clinical use in childhood heart disease since the scan and analysis times are relatively short.     

Effects of storage duration and volume on the quality of leukoreduced apheresis‐derived platelets: implications for pediatric transfusion medicine

BACKGROUND: Platelet (PLT) storage adversely affects PLT structure and function in vitro and is associated with decreased PLT recovery and function in vivo. In pediatric transfusion medicine, it is not uncommon for small residual volumes to remain in parent units after aliquot preparation of leukoreduced apheresis‐derived PLTs (LR‐ADP). However, limited data exist regarding the impact of storage on residual small‐volume LR‐ADP. STUDY DESIGN AND METHODS: Standard metabolic testing was performed on residual volumes of LR‐ADP after aliquot removal and PLT aggregometry using a dual agonist of ADP and collagen was performed on stored, small‐volume aliquots (10‐80 mL) created from an in vitro model of PLT storage. RESULTS: Seventy‐seven LR‐ADP underwent metabolic (n = 67) or metabolic and aggregation (n = 10) studies. All products maintained a pH value of more than 6.89 throughout storage. Lactate and pCO₂ increased proportionally with longer storage time. Regardless of acceptable metabolism during storage, aggregation in 10‐ to 20‐mL aliquots was impaired by Day 4 and aliquots less than 40 mL demonstrated the most dramatic decrease in aggregation from baseline. CONCLUSIONS: Despite maintenance of acceptable metabolic conditions, residual volumes of LR‐ADP develop impaired aggregation in vitro that may adversely affect PLT survival and function in vivo. At volumes below 40 mL, LR‐ADP revealed reduced aggregation. As a result, it is recommended to monitor and record volumes of LR‐ADP used for pediatric transfusion. Moreover, once LR‐ADP attain a volume of 50 mL or less on Day 4 or Day 5 of storage, consider discarding these products until their in vivo efficacy can be studied.     

应用超声和圆锥体公式测算胆囊容积

目的 评价圆锥体公式计算胆囊容积的临床实用性和准确性。方法 利用B型超声测量12例接受胆囊切除术患者术前胆囊各径线,分别用圆锥体公式、椭圆体公式计算肿囊容积,手术切除胆囊后测得容积为实际容积,对比分析3种方法的测算结果,探讨圆锥体公式计算胆囊容积的准确性。结果 圆锥体公式计算所得的胆囊容积较椭圆体公式更为接近实际测量数值,两方法所计算出的胆囊容积差别有显著性意义（P＜0．05）;椭圆体公式计算结果与实际容积间差别有显著性意义（P＜0．05）,而圆锥体公式结果与实际容积间未见统计学差异（P＞0．05）。结论 圆锥体公式比椭圆体公式更接近实际容积并可以代表胆囊实际容积。     

Estimation of the right ventricular volume and ejection fraction by transthoracic three-dimensional echocardiography

Aims. To validate the use of three-dimensional transthoracic echocardiography compared with the magnetic resonance imaging for determination of right ventricular volume and ejection fraction. Methods and results: We recorded transthoracic echocardiographic images starting from the apical four-chamber view in which the RV is clearly visualized in 15 healthy volunteers. The scanning plane of the RV was obtained by the rotational scanning technique in 2 degree angular increments for three-dimensional reconstruction. The RV volumes in end-diastole and end-systole were calculated using a Tomtec three-dimensional reconstruction computer. We also assessed the RV by cine magnetic resonance imaging using the Siemens Magnetom Impact Expert (1.0 T). Cine gradient echo images were obtained in the short axis of the RV. The RV volume at each phase was calculated by Simpson's method. We also calculated the RV ejection fraction. The RV volumes in end-diastole and end-systole were 111±22 ml and 52±13 ml, respectively as determined by three-dimensional echo, and 115±18 ml and 55±14 ml determined by MRI. The right ventricular volumes at end-diastole and end-systole determined by three-dimensional echo were correlated with the volumes determined by MRI (r=0.94 and 0.97, respectively, p<0.001). The RV ejection fraction determined by three dimensional echo was also correlated with the ejection fraction determined by MRI (r=0.90, p<0.01). Conclusions. Three-dimensional transthoracic echocardiography provided reliable calculations of the right ventricular volume and ejection fraction.     

Reliability and validity of two methods of three-dimensional cervical volume measurement.

OBJECTIVES: To determine if cervical length obtained with three-dimensional ultrasound correlated with the 'true cervical volume' and to evaluate the reliability and validity of transabdominal and transvaginal three-dimensional cervical volume measurement. METHODS: This was a prospective observational study. Three-dimensional cervical volume measurements were made prior to hysterectomy in 28 women. Following hysterectomy the amputated cervical volume was calculated using water displacement. For the assessment of intra- and interobserver reliability, the intraclass correlation coefficient (ICC) was used. The index of concordance between the sonographic cervical volumes and those obtained by the reference standard (true cervical volume) was assessed with the limits of agreement method and the ICC. RESULTS: Transabdominal cervical length and transvaginal cervical length correlated moderately with actual cervical volume; correlation coefficients were 0.64 and 0.57 (P < 0.05), respectively. Intraobserver reliability for both transabdominal and transvaginal cervical volume assessment was good (> 0.75). Interobserver reliability for transvaginal cervical volumes was similarly good (ICC = 0.90). However, for transabdominal measurements the interobserver reliability was poor (ICC = 0.51). The validity of both methods of three-dimensional volume assessment was poor (ICC < 0.75). This was reflected in the wide limits of agreement, which ranged from approximately - 25 mL to + 30 mL. CONCLUSION: The reliability and validity of three-dimensional cervical volume measurement are poor. Clinical introduction of cervical volume measurement should be avoided at this time.     

Carcinoma of the gallbladder: role of sonography in diagnosis and staging

PURPOSE: In an attempt to define the sonographic characteristics of gallbladder cancer, we retrospectively analyzed the sonographic findings in 203 cases of gallbladder cancer confirmed by cytology or histopathology. Patients and Methods Patients with proven gallbladder cancer presenting to a single surgical unit between 1991 and 1995 were identified through a records search. All patients underwent sonographic examination followed by fine-needle aspiration (FNA), biopsy, or laparotomy for establishing the diagnosis. RESULTS: A mass in the gallbladder and gallbladder wall thickening (> 12 mm) were cardinal sonographic findings of carcinoma. Liver infiltration was correctly identified in all patients who had it. Sonography was highly accurate for detecting mass lesions, gallstones, liver infiltration, metastasis, and ascites. However, visualization of lymph nodes, common bile duct infiltration, and peritoneal dissemination was poor. CONCLUSIONS: Sonography was found to be a good diagnostic tool for carcinoma of the gallbladder; however, its sensitivity was poor for staging nodal spread of the disease.     

A new angle-independent Doppler ultrasonic device for assessment of blood flow volume in the extracranial internal carotid artery.

OBJECTIVE: To evaluate a new angle-independent ultrasonic device for assessment of blood flow volume in the internal carotid artery. METHODS: In vitro, a pulsatile pump was set to provide an outflow of physiological fluid at 500 mL/min through an 8-mm-diameter tube. Flow volume rates were measured 10 times by 10 different operators and compared with time-collected flow volume rates. In vivo, internal and common carotid artery blood flow volumes were measured in 28 volunteers by 2 operators using a FlowGuard device (Biosonix Ltd). Internal and common carotid artery diameters and blood flow volumes were also assessed by Duplex sonography and compared with FlowGuard measurements. In 10 volunteers, internal carotid artery blood flow volume changes in response to monitored breath manipulations were recorded. RESULTS: In vitro, intraoperator variability was 4.04% (range, 2%-5.7%). The mean error rate +/- SD was 3.54% +/- 0.8% (range, 2.7%-5.2%). In vivo, the mean common carotid artery blood flow volume was 456 +/- 39 mL/min (range, 417-583 mL/min) with a mean diameter of 6.7 +/- 0.7 mm (range, 5.8-8.7 mm). The mean internal carotid artery blood flow volume was 277 +/- 25 mL/min (range, 239-338 mL/min) with a mean diameter of 5 +/- 0.5 mm (range, 4.1-6.1 mm). No significant difference was found between operators. Internal carotid artery diameter and blood flow volume measured by the FlowGuard were closely correlated with the results of Duplex sonography. Repeated shifts of end-tidal CO2 induced reproducible changes in internal carotid artery flow volume: 187.5 +/- 18.1 mL/min at 26.8 +/- 1.9 mm Hg and 382.1 +/- 18.2 mL/min at 47 +/- 2.2 mm Hg. CONCLUSIONS: The FlowGuard showed that volume flow studies in the internal carotid artery could be easily performed, with results compatible with those of previous clinical reports. Duplex comparative results and breath-induced changes in internal carotid artery flow volume justify further evaluation of the system.     

New echocardiographic and angiographic methods for right atrial volume determination: In vitro validation and in vivo results

Until now, right atrial (RA) volume calculation by means of two-dimensional echocardiography (2-DE) has only been attempted in a single plane: the apical four-chamber view. Our study reports a new method for RA volume calculation using two intersecting 2-DE views. For this purpose, silicone rubber casts of 19 human necropsy hearts were obtained and thin-walled natural rubber moulds of the RA casts were prepared. Totally filled with and immersed in water, the moulds could be visualized in the apical four-chamber view and an additional 2-DE plane, the latter corresponding to the subcostal view in vivo. In this view the vertical extension of RA could be estimated. Areas and lengths of RA were determined in the respective planes, and RA volume was calculated by applying the formula, area x length, to two intersecting planes. Finally, volume of the silicone casts was determined angiocardiographically (Angio) using a biplane method (30° RAO, 40° LAO-40° hepatoclavicular). The true RA volume was 106±23 ml (mean±1SD) as determined by water displacement. Using Angio an excellent correlation was found: the calculated volume amounted to 106±23ml; the difference was 5.5±4.8ml (n.s.); Angio vol=0.93 true vol+ 7.77; r=0.95; SEE= 7,4 ml. Volume determination from the apical four-chamber view of 2-DE using a monoplane disk method resulted in a mean volume of 62±17 ml. The mean difference to the true RA volume was 44±16 ml (p < 0.001). When volume calculations were made using the biplane method, a value of 105±22 ml resulted. The mean difference to true volumes was 7.4±4.8 ml: y=0.84x + 15.88; r=0.91; SEE=9.4 ml. In an in vivo study endsystolic RA volumes were calculated in a normal adult population (n=40) from the same intersecting planes as in vitro. A normal value of 38±6 ml/m² was found. In vivo validation using Angio showed a slightly higher normal value of 43=7 ml/m². Thus, 2-DE is highly accurate in determinating RA volume. In the in vitro as well as in the in vivo study the results of monoplane calculations are clearly inferior to a method which also takes account of the vertical extension of RA.     

Is Same‐Day Sonography of the Gallbladder Feasible After Intravenous Urography or Contrast‐Enhanced Computed Tomography?

OBJECTIVE: To determine whether same-day sonographic evaluation of the gallbladder is possible after the use of oral or intravenous iodinated contrast agents during intravenous urography or computed tomography. METHODS: One hundred fifty-three patients involved in this prospective study received low-osmolar or conventional contrast material. Each preparation contained 300 mg/mL iodine. Sixty-six patients received contrast agents intravenously, and 87 received them orally. Gallbladder volume was estimated sonographically, and the precontrast volume was used to calculate the volume after contraction at 30-minute intervals up to 2 hours after contrast agent administration. RESULTS: Gallbladder volume returned to precontrast values at 2 hours irrespective of the type of contrast agent or route of administration. The mean volume after contraction at 0.5 hour was 71% after intravenous contrast agent administration and 76% after oral contrast agent administration. Both changes were statistically significantly different from precontrast values (P < .01, null hypothesis) and were unaffected by the osmolarity of the contrast agent. CONCLUSIONS: Gallbladder volume was restored to precontrast values 2 hours after contrast agent administration. Thus any strategy involving simultaneous same-day sonographic or computed tomographic assessment of the gallbladder after contrast agent administration can be confidently undertaken after this period. This finding may have cost-saving implications.     

Three-dimensional sonographic volumetry of the placenta and the fetus between weeks 15 and 17 of gestation.

OBJECTIVES: Three-dimensional sonographic volume measurement enables for the first time direct comparison of the increase in size of different but closely interacting structures like the placenta and fetus. Our aim was to calculate the fetal and placental volumes between weeks 15 and 17 of gestation, to monitor the difference in the increase of the fetal and placental sizes and to determine their mutual relationship. METHODS: Fetal and placental sonographic volume measurements were made in 356 singleton pregnancies. To measure the relationship between fetal and placental volumes, a quotient was calculated. Regression analyses were performed to analyze the dependence of the fetal and placental volumes and placental quotient on the week of gestation and other influencing variables. RESULTS: The mean of the fetal volume increased markedly from 67.8 to 76.6 mL (by 13%) within the 3 weeks of observation, whereas placental volume increased only slightly (111.1 to 114 mL (by 2.6%)). The random variation of placental volumes around the mean in all three gestational weeks was considerably higher than that of fetal volumes, indicating that in this early period of gestation there is little correlation between fetal and placental sizes. Fetal volume correlated better to gestational week than did placental volume. CONCLUSION: The quotient of fetal and placental volume might assist in the diagnosis of high-risk pregnancies and the assessment of a normal or large fetus with a small placenta.     

Sonographic evaluation of gallbladder kinetics: in vitro and in vivo comparison of different methods to assess gallbladder emptying.

In an in vitro study, 10 gallbladders of adult pigs and 6 gallbladders of lambs, all removed immediately after slaughtering, were stimulated in a water bath by electric means to induce active contraction. Gallbladder emptying was followed by ultrasonography employing five measurement procedures: (1) gallbladder width, (2) longitudinal planimetry, (3) transverse planimetry, (4) ellipsoid method, and (5) sum of cylinders method. In an in vivo investigation, gallbladder emptying of 30 volunteers (12 healthy subjects, 18 diabetics) was evaluated in the same way after ingestion of a fatty meal. Gallbladder width was found to be unsuitable to estimate the decrease in gallbladder volume due to a nonlinear relation of the parameters. Longitudinal planimetry tended to be less valid than transverse planimetry in assessing gallbladder volume reduction. The most valid estimation of gallbladder volume decreases was obtained by the two three-dimensional procedures. However, in neither in vitro nor in vivo could a significant difference between the sum of cylinders method and the ellipsoid method in determining relative volume reduction be established. We conclude that a three-dimensional measurement procedure should be used for valid assessments of gallbladder motility. However, according to our data there is no advantage in using the time-consuming sum of cylinders method compared to the simple ellipsoid method.