Fiona Brook

Sonographic appearance and distribution of normal cervical lymph nodes in a Chinese population

In 100 normal subjects who had a sonographic examination of the neck, 1211 lymph nodes were detected. In all the subjects, at least five lymph nodes were seen. The distribution, number, echogenicity, shape, presence or absence of echogenic hilus, and the sharpness of nodal borders of normal cervical lymph nodes were determined. The usefulness of these sonographic features in understanding the normal distribution and characteristics of the nodes in the Chinese population is discussed. The relationship between the shape and size of lymph node also was assessed.

Power Doppler Sonography of Normal Cervical Lymph Nodes

This study was undertaken to investigate the vascular patterns and resistance of normal cervical nodes by power Doppler sonography. In 101 subjects who had a sonographic examination of the neck, 1050 lymph nodes were detected. Only central vascularity was found in normal cervical nodes. The degree of vascularity in submental and submandibular nodes was higher than that in other regional nodes. Submental nodes had a higher vascular resistance in association with a lower blood flow velocity than other regional nodes. No significant difference was found in blood flow velocities and vascular resistance between male and female subjects. The vascular resistance increased significantly with age. This study provides a baseline for vascularity within normal cervical nodes, as seen by power Doppler sonography.

Nodal shape (S/L) and its combination with size for assessment of cervical lymphadenopathy: which cut-off should be used?

The short axis to long axis (S/L) ratio is commonly used to assess cervical lymphadenopathy; however, the cut-off value used has been limited to 0.5. The accuracy of the combination of S/L ratio and nodal size has not been documented previously. We evaluated 1143 normal cervical nodes from 95 healthy subjects, and 1441 nodes from 290 patients with proven cervical lymphadenopathy. The optimum cut-off value of the S/L ratio was determined in different regions of the neck: submental (0.5), submandibular (0.7), parotid (0.5), upper cervical (0.4), middle cervical (0.3) and posterior triangle (0.4). In the submandibular and parotid regions, the combination of the S/L ratio and short axis shows substantial improvement in diagnostic accuracy when compared to the S/L ratio alone.

Alteration of thyroid blood flow during the normal menstrual cycle in healthy Chinese women

The purpose of this study was to investigate the relationship between thyroid activity and the menstrual cycle by measuring the Doppler parameters of the superior thyroid arteries in women of reproductive age. The study was performed in 27 healthy Chinese women aged between 19 and 28 y for one menstrual cycle, and 25 age-matched healthy Chinese men for 3 weeks for comparison. In women, the peak systolic velocity increased from the follicular phase to the luteal phase, and the pulsatility index decreased from the follicular phase to the ovulatory phase and increased slightly in the luteal phase. In men, alterations in the pattern of thyroid blood flow were not observed; however, the average values of Doppler parameters during the study period in women were similar to those in men. The gender difference in the pattern of flow characteristics in the superior thyroid artery suggests effects of estrogen on thyroid function.

Repeatability of power doppler sonography of cervical lymph nodes

This study was undertaken to investigate the repeatability (intraobserver variability) of power Doppler sonography in assessment of cervical lymph nodes. Power Doppler sonography was performed twice in 20 healthy subjects to evaluate the repeatability of measurement of size, blood flow velocity (peak systolic velocity, PSV, and end diastolic velocity, EDV) and vascular resistance (resistance index, RI, and pulsatility index, PI) of cervical nodes. A total of 70 power Doppler sonograms were reviewed to evaluate the repeatability of assessment of vascular pattern, degree of vascularity and displacement of vessels of cervical lymphadenopathy. In the 20 subjects, 139 normal cervical nodes were detected in the first scan and they were re-scanned in the second scan. One node was detected in the second scan, but not in the first scan. Of the total, 50 cervical nodes showed arterial flow in both scans, and blood flow velocity and vascularity resistance were measured. The mean value of PSV, EDV, RI and PI have a higher repeatability than their highest and lowest values. There is a high repeatability in the measurement of maximum transverse diameter (97%), mean PSV (95%), mean EDV (96%), mean RI (86%) and mean PI (87%). The repeatability in evaluation of vascular pattern (85%), degree of vascularity (95%) and displacement of vessels (88%) are also high. Results suggest that power Doppler sonography is a reliable method in assessment of the vasculature of cervical lymph nodes.

Gray Scale and Power Doppler Sonography of Normal Cervical Lymph Nodes Comparison Between Chinese and White Subjects

Objective. To investigate the racial difference in gray scale and power Doppler sonography of cervical lymph nodes between white and Chinese subjects. Methods. Twenty healthy white subjects and 20 healthy Chinese subjects had sonographic examination of the neck. They were age and sex matched. Lymph nodes were evaluated for their number, size, site, echogenic hilus, vascular pattern, degree of vascularity, blood flow velocity, and vascular resistance. Results. A total of 184 lymph nodes were detected in the 20 white subjects, and 196 lymph nodes were found in the 20 Chinese subjects. There were no significant differences in the number, size, and distribution of the lymph nodes between the 2 populations. One hundred ninety‐six region‐ and size‐matched lymph nodes were selected from the 2 groups of subjects (98 nodes from each group) for evaluation of echogenic hilus, vascular pattern, degree of vascularity, blood flow velocity, and vascular resistance. There was no significant difference in the gray scale and vascular features of cervical nodes between white and Chinese subjects. Conclusions. There is no significant racial difference in the gray scale appearance of cervical lymph nodes. Unlike some other body regions, there is no significant vascular difference between white and Chinese populations. Results on power Doppler and gray scale sonographic assessment of cervical lymphadenopathy reported in previous studies may be applicable in both populations.

The value of thyroid parenchymal echogenicity as an indicator of pathology using the sternomastoid muscle for comparison

This study was undertaken to evaluate the diagnostic accuracy of comparison of the echogenicity of the thyroid gland with the sternomastoid muscle in diagnosis of thyroid disorders. Fifty healthy subjects underwent a thyroid ultrasound, and 80 patients with archived thyroid ultrasound examinations (50 thyrotoxicosis and 30 thyroiditis) were reviewed. Images were measured for the image density of the thyroid gland and the sternomastoid muscle, using a transmission densitometer. Healthy thyroid was relatively hyperechoic when compared with the sternomastoid muscle (100%). Of the thyrotoxic patients, 70% showed a relatively hyperechoic thyroid compared to 47% of the thyroiditis patients. Mean image density difference in healthy thyroid, thyrotoxicosis and thyroiditis ranged from 0.1 to 1, -0.42 to 0.83, and -0.55 to 0.58, respectively. In conclusion, the relative echogenicity of the thyroid gland when compared with the sternomastoid muscle may be useful to differentiate healthy thyroid from thyrotoxicosis and thyroiditis, but does not help to distinguish thyrotoxicosis from thyroiditis. An image density difference of less than 0.1 may be considered to be abnormal, whereas a value greater than 0.83 may be considered to be normal.

Semen collection and ejaculate characteristics in the Indo-Pacific bottlenose dolphin (Tursiops aduncus).

The testes of sexually mature dolphins produce large quantities of sperm. Sperm are expelled in copious amounts of seminal fluid through repeated ejaculations that can occur within a short period of time. There is currently a lack of detail about the methodology of sequential ejaculate collection in dolphins and how the traits of individual ejaculates affect the assessment of reproductive capacity. The objectives of this study were to obtain series of ejaculates from 3 dolphins by following a well-defined collection protocol and then to characterize individual ejaculates. Semen was collected weekly for 1 year from 3 sexually mature Tursiops aduncus. The end of a collection session was marked by a lack of semen, in spite of effort, or micturition. Individual ejaculates were analyzed for volume, pH, and sperm concentration, count, motility, and viability following methods previously described for dolphin semen. The first ejaculate was typically higher in volume and sperm count but lower in sperm concentration, motility, and viability. The concentration of the second ejaculate was generally the highest. Sperm motility and viability of the second and subsequent ejaculates in a series were good (ie, >80%). Collection of the first ejaculate only can lead to underestimation of reproductive capacity. Sperm output fluctuated erratically from week to week, so it was difficult to assess any seasonal pattern. Results provide information for further investigation of male dolphin reproductive patterns and any effect of collection frequency on ejaculate characteristics.

Relationship of thyroid blood flow to reproductive events in normal chinese females

The purpose of this study was to investigate the blood flow characteristics in the superior thyroid artery (STA) in normal females of prepubertal, reproductive, and postmenopausal age. The study was performed in 29 prepubertal girls, 27 females of reproductive age, and 26 postmenopausal women. The peak systolic velocity (PSV) and the pulsatility index (PI) of the STA were measured repeatedly during one menstrual cycle in females of reproductive age, and measured once in each prepubertal and postmenopausal subject. Different waveforms were observed in females of prepubertal, reproductive, and postmenopausal age. The PSV of the STA increased progressively in females from prepubertal to postmenopausal phases. The PI of the STA in all of the prepubertal girls was lower than that of adult females in different phases of the menstrual cycle. In adult females, the PI in the follicular phase was significantly higher than those in the ovulatory and luteal phases. In all of the postmenopausal women, the PI was comparable to that in older prepubertal subjects and in adult females during the ovulatory and luteal phases. The results suggest that oestrogen may affect thyroid blood flow during the normal menstrual cycle. Growth and progressive change of arterial structure are suggested to affect the thyroid blood flow in prepubertal and postmenopausal states.

Ultrasonographic assessment of the thyroid gland and adjacent anatomic structures in Indo-Pacific bottlenose dolphins (Tursiops aduncus).

OBJECTIVE To evaluate the use of ultrasonography for thyroid gland assessment in healthy Indo-Pacific bottlenose dolphins (Tursiops aduncus), describe the ultrasonographic appearance of the thyroid gland and adjacent anatomic structures, and identify potential associations between variations in thyroid gland morphology and demographic features in this species. ANIMALS 18 captive Indo-Pacific bottlenose dolphins. PROCEDURES 1,404 ultrasonographic examinations of the thyroid gland and adjacent anatomic structures (eg, cervical lymph nodes, musculature, and vasculature) were performed during the > 3-year study period. Shape, echogenicity, and homogeneity of thyroid glands were assessed, and glands were categorized into morphological configurations on the basis of results of 2-D and 3-D ultrasonographic evaluation. Associations between demographic factors and thyroid gland morphology were assessed. RESULTS Thyroid lobes appeared elliptical or fusiform in the transverse scan plane and round to oval in longitudinal scan planes; morphologically, glands comprised 2 lobes joined by an isthmus or a roughly diamond-shaped structure located on the ventral surface of the trachea. Major blood vessels and cervical lymph nodes were identified. Thyroid parenchyma was typically uniform and homogeneous, with echogenic reticulations and well-defined borders. Thyroid glands were hypoechoic or isoechoic relative to the sternocephalicus muscle; echogenicity was greater in adolescents than in adults. Thyroid gland volume differed between sexes, between sexually mature and immature dolphins, and among age groups and was positively correlated with body length and weight. CONCLUSIONS AND CLINICAL RELEVANCE Ultrasonography provided a reliable and repeatable method for evaluation of thyroid glands and adjacent anatomic structures in live dolphins.