Ovarian cancer detected non-invasively by contrast-enhanced power Doppler ultrasound

Overall, about one-third of women operated upon because of suspected ovarian cancer turn out to have benign disease. This proportion will be even higher when the tumours are small. A more accurate method of determining which are malignant would reduce the number of unnecessary referrals to the cancer centre and increase the scope for conservative management. This pilot study of ultrasound and intravenous microbubble contrast in 20 women with small ovarian tumours enabled the identification of all four malignant lesions with good inter-observer agreement. These preliminary findings suggest that intravenous contrast improves the ultrasound identification of small ovarian malignancies and may provide an accurate way of selecting women who require to be referred urgently for surgery under the auspices of a gynaecological oncologist. The remainder might be considered for laparoscopic surgery or even for observation in some cases.

Standards for the management of cervical and vulval carcinoma

OBJECTIVE

To examine the feasibility of achieving designated target standards for the management of women with cervical and vulval cancer.

DESIGN

Retrospective casenote review.

SETTING

The Gynaecological Oncology Centre at Hammersmith Hospital, London.

POPULATION

Sixty-one women with cervical and vulval cancer presenting to the gynaecological oncology clinic at the Hammersmith Hospital during 1996 and 1997. Various aspects of the management of those women were compared with standards suggested by a multidisciplinary panel of local experts. Targets included the referral and treatment process, the accuracy of staging, and measures of surgical performance.

RESULT

The target interval of seven days between receipt of the referral and the first visit at the cancer centre was achieved in 93% of women. Surgical treatment was administered to 92% of the women within the target of 20 working days from the first clinic appointment. Tumour close to or involving the margins of the specimen was noted in 13% of cervical and 9% of vulval cancers. The node count fell below the target standards in 13% of pelvic and 10% of groin dissections. Appropriate imaging investigations for staging were not undertaken in 15 of 39 cases (38%) of cervical cancer and in 5 out of 22 (23%) of vulval cancers.

CONCLUSION

The suggested targets of process and surgical performance are reasonable and achievable. These standards would be appropriate for national use. The area most clearly identified where these targets were not achieved was the requesting of complementary staging investigations. This could be addressed by the use of a simple investigation protocol to be included in each patient's notes and available at specialist clinics and gynaecology wards.

In vitro estimation of foetal liver volume using ultrasound, x-ray computed tomography and magnetic resonance imaging

Sixteen formalin-fixed foetal livers were scanned in vitro using a new system for estimating volume from a sequence of multiplanar 2D ultrasound images. Three different scan techniques were used (radial, parallel and slanted) and four volume estimation algorithms (ellipsoid, planimetry, tetrahedral and ray tracing). Actual liver volumes were measured by water displacement. Twelve of the sixteen livers also received x-ray computed tomography (CT) and magnetic resonance (MR) scans and the volumes were calculated using voxel counting and planimetry. The percentage accuracy (mean +/- SD) was 5.3 +/- 4.7%, -3.1 +/- 9.6% and -0.03 +/- 9.7% for ultrasound (radial scans, ray volumes), MR and CT (voxel counting) respectively. The new system may be useful for accurately estimating foetal liver volume in utero.

The accuracy of a new system for estimating organ volume using ultrasound

A new system is described for estimating volume from a series of multiplanar 2D ultrasound images. Ultrasound images are captured using a personal computer video digitizing card and an electromagnetic localization system is used to record the pose of the ultrasound images. The accuracy of the system was assessed by scanning four groups of ten cadaveric kidneys on four different ultrasound machines. Scan image planes were oriented either radially, in parallel or slanted at 30 degrees to the vertical. The cross-sectional images of the kidneys were traced using a mouse and the outline points transformed to 3D space using the Fastrak position and orientation data. Points on adjacent region of interest outlines were connected to form a triangle mesh and the volume of the kidneys estimated using the ellipsoid, planimetry, tetrahedral and ray tracing methods. There was little difference between the results for the different scan techniques or volume estimation alogorithms, although, perhaps as expected, the ellipsoid results were the least precise. For radial scanning and ray tracing, the mean and standard deviation of the percentage errors for the four different machines were as follows: Hitachi EUB-240, -3.0 +/- 2.7%; Tosbee RM3, -0.1 +/- 2.3%; Hitachi EUB-415, 0.2 +/- 2.3%; Acuson, 2.7 +/- 2.3%.

Estimation of fetal lung volume using enhanced 3-dimensional ultrasound: a new method and first result

OBJECTIVE

To measure fetal lung volume using a computer based, enhanced, 3-dimensional ultrasound imaging system.

DESIGN

An observational study.

SETTING

The Fetal Medicine Unit at Guys Hospital, London.

PARTICIPANTS

Twenty healthy women with a singleton pregnancy between 24 and 36 weeks of gestation were scanned on one occasion during pregnancy using an ultrasound based 3-dimensional imaging system. All delivered at term with weights above the 10th centile for gestation.

RESULTS

Total lung volume increased exponentially with gestational age. Right lung volume measured consistently greater than left lung volume.

CONCLUSIONS

The use of this new enhanced 3-dimensional imaging system allows for estimations of fetal lung volume. Preliminary data confirm that fetal lung volume, measured by a computerised 3-dimensional ultrasound imaging system increased exponentially with gestational age. The use of this system has obvious application in the further study of lung growth in utero and possible clinical application in disease states where fetal lung growth may be impaired.

Application of a new discreet form of Gauss' theorem for measuring volume

Volume measurements are useful in many branches of science and medicine. They are usually accomplished by acquiring a sequence of cross sectional images through the object using an appropriate scanning modality, for example x-ray computed tomography (CT), magnetic resonance (MR) or ultrasound (US). In the cases of CT and MR, a dividing cubes algorithm can be used to describe the surface as a triangle mesh. However, such algorithms are not suitable for US data, especially when the image sequence is multiplanar (as it usually is). This problem may be overcome by manually tracing regions of interest (ROIs) on the registered multiplanar images and connecting the points into a triangular mesh. In this paper we describe and evaluate a new discreet form of Gauss' theorem which enables the calculation of the volume of any enclosed surface described by a triangular mesh. The volume is calculated by summing the vector product of the centroid, area and normal of each surface triangle. The algorithm was tested on computer-generated objects, US-scanned balloons, livers and kidneys and CT-scanned clay rocks. The results, expressed as the mean percentage difference +/- one standard deviation were 1.2 +/- 2.3, 5.5 +/- 4.7, 3.0 +/- 3.2 and -1.2 +/- 3.2% for balloons, livers, kidneys and rocks respectively. The results compare favourably with other volume estimation methods such as planimetry and tetrahedral decomposition.

Volume estimation from multiplanar 2D ultrasound images using a remote electromagnetic position and orientation sensor

A system is described for calculating volume from a sequence of multiplanar 2D ultrasound images. Ultrasound images are captured using a video digitising card (Hauppauge Win/TV card) installed in a personal computer, and regions of interest transformed into 3D space using position and orientation data obtained from an electromagnetic device (Polhemus, Fastrak). The accuracy of the system was assessed by scanning 10 water filled balloons (13-141 mL), 10 kidneys (147-200 mL) and 16 fetal livers (8-37 mL) in water using an Acuson 128XP/10 (5 MHz curvilinear probe). Volume was calculated using the ellipsoid, planimetry, tetrahedral and ray tracing methods and compared with the actual volume measured by weighing (balloons) and water displacement (kidneys and livers). The mean percentage error for the ray tracing method was 0.9 +/- 2.4%, 2.7 +/- 2.3%, 6.6 +/- 5.4% for balloons, kidneys and livers, respectively. So far the system has been used clinically to scan fetal livers and lungs, neonate brain ventricles and adult prostate glands.