Determination of thyroid volume in infants with suspected congenital hypothyroidism—the limitations of both subjective and objective evaluation

Objective: To compare two methods of assessing gland size on thyroid ultrasound in newborn infants with suspected congenital hypothyroidism (CH). Methods: Images from infants with eutopic glands referred between 2007 and 2013 were evaluated blind by two sets of observers. Subjective gland size was categorised as small, borderline-small, normal, borderline-large and large. Objective gland volume, calculated as the sum of each lobe using the prolate ellipsoid formula (length x width x depth x π/6), was put into corresponding categories: <0.8, 0.81–1.0, 1.1– <2.2, 2.2–2.4 and >2.4 ml, derived from normative Scottish data. Results: Of 36 infants, permanent CH was present in 17, transient CH in 17, status uncertain in 2. Mean (SD) intraobserver error for thyroid volume measurement was 0.11 (0.23) ml [8.3%]. Subjective assessment by two observers was discordant in only four (10.8%) infants. However, subjective vs objective evaluation was discordant in 14 (39%). Eight (three permanent, five transient CH) had large glands subjectively but normal glands objectively; and six (four transient CH) had normal glands subjectively but small glands objectively. The former infants all showed a single flattened curve to the anterior thyroid margin, giving an impression of bulkiness. Gland shape was normal in the latter infants. Conclusion: Neither subjective nor objective evaluation predicts permanent vs transient CH. Altered gland shape may confound both methods, and undermine use of the conventional formula for measuring lobe volume. Advances in knowledge: Until more refined methods are available for assessing thyroid size, both subjective and objective evaluation are recommended in CH.

An approximation of geodesic circle passing through three points on an ellipsoid

In this paper we present an approximation method for a geodesic circle passing through three points on an oblate ellipsoid. Our method uses a prolate ellipsoid passing through the three points, and the new approximation curve is the intersection of the oblate and prolate ellipsoids, which can be obtained algebraically without iterations. The advantage of our approximation method is that it yields a significantly smaller approximation error. Compared to the plane section curve passing through the three points on the oblate ellipse, our method reduces the approximation error by at least 98\hspace{0.1667em}\% when the radii of geodesic circles are 100 km∼1000 km on the surface of the Earth. We illustrate the results using numerical examples.

Comparison of Spleen Volumes Estimated Using Planimetry and Prolate Ellipsoid Methods on MRI in Myelofibrosis Patients

Background: Splenomegaly is one of the most characteristic features of myelofibrosis (MF) with significant impact on the quality of life of patients. About 10% of MF patients present with severely symptomatic splenomegaly at diagnosis; another 50% develop it within 4 years of diagnosis. Pharmaceutical drug trials aimed at treating myelofibrosis have assessment of spleen size as one of its key trial endpoints. While assessment of spleen size (volume) by palpation is routinely performed in the clinic, unfortunately, it is not a precise and reliable method, a key requirement in drug trials. Medical imaging methods such as magnetic resonance imaging (MRI) and computed tomography (CT) provide a non-invasive approach to assessment of spleen volume. Both modalities allow acquisition of cross sectional abdominal images and enable full anatomical coverage of the spleen. Due to radiation concerns, MRI is preferred over CT modality. There are two approaches for analyzing cross sectional images for estimation of spleen volume - the planimetry method, that involves delineating spleen contours on each spleen slice to estimate complete spleen volume and the prolate ellipsoid method, that approximates the spleen to an ellipsoid structure and estimates spleen volume by using the prolate ellipsoid method (described below). The prolate method is a simple and quick way to assess spleen size compared to the planimetry method. However, the former method provides an approximate estimate of spleen size. The goal of this study was to compare the prolate method with planimetry method for estimating spleen volume for use in pharmaceutical clinical trials. Methods: A retrospective assessment of spleen volume in N=30 subjects with confirmed diagnosis of myelofibrosis was performed. All measurements were performed on T2 weighted MR images (5mm slice thickness/0.0 gap), acquired on MRI scanners from different manufacturers. All images were assessed for image quality prior to including them in the analysis and images without any images quality issues were included in this study. The analysis methods and calculation used for estimating spleen volume were as below:Planimetry: Volume = ∑ [(Region of interest outlining the spleen boundary per slice) x (Slice thickness)].Prolate Ellipsoid: Volume = 0.52 x (Longest diameter of the spleen) x (longest perpendicular diameter on the same trans-axial slice) x (vertical distance between the most superior and most inferior margins of the spleen) Results: Spleen volume estimated by planimetry and prolate method was 2113cc±1612cc and 2186cc±1538cc (mean ± Standard Deviation [S.D.]). The range of planimetry spleen volumes in this study was 210 to 5750cc. A plot of spleen volumes estimated using planimetry and prolate method showed high correlation (R2 = 0.97) between the two methods, however, the volume variation tends to increase for large spleen sizes. The Bland-Altman plot for comparing the two methods showed mean difference in measures (73 cc) and difference variation (1 S.D. =300cc). Conclusions: Prolate method is a simple and useful alternate method for assessing spleen volume that does not require any specialized software for delineating spleen boundaries. However, the implementation of prolate method is operator dependent and requires precise positioning of digital calipers on images. Future work involves comparing the two methods with respect to change in spleen volume compared to baseline, an assessment performed routinely in pharmaceutical clinical trials. Disclosures No relevant conflicts of interest to declare.

Ex-situ Morphological and Morphometric Studies of the Testis In the West African Dwarf Buck GoatEx-situ Morphological and Morphometric Studies of the Testis In the West African Dwarf Buck Goat

This study was carried out to document ex-situ morphological and morphometric characteristics of the testis in the West African Dwarf (WAD) buck goat. For this aim, 24 post pubertal WAD buck testes were collected at the Ipata Abattoir in Ilorin, Kwara state, Nigeria. Gross morphologic results revealed that WAD testis was ellipsoidal in shape with 2 borders (free and attached), margins (medial and lateral) and similar surfaces (ventral and dorsal). The surfaces were covered by an outer tunica vaginalis and a deep tunica albuginea. Histomorphology showed the testis comprised mostly of rounded and some irregularly shaped seminiferous tubules (ST). Each ST was lined by a basement membrane and a layer of germinal epithelium with lumen filled with spermatozoa surrounded by an adluminal space. Gross morphometric results showed that there were no significant differences in the weight, length, width and height of the right and left testis. Also in the volumes of testes obtained by water displacement method and using the prolate ellipsoid formula. There was a strong correlation between the weights and volumes of testes obtained using these methods. There were significant differences between the volumes of testes obtained by using the prolate spheroid and Lambert formulae, when compared with those obtained by water displacement method respectively. But there was no significant difference in testicular volume obtained by the prolate ellipsoid formula and the water displacement method. Histomorphometric results revealed no significant differences in the seminiferous tubular diameter, seminiferous luminal diameter and germinal epithelia height of the right and left testes respectively. The morphological and morphometric data highlighted in this study would be useful in comparative regional anatomy and researches on the testis of these valuable breed of goats.

Ex-situ Morphological and Morphometric Studies of the Testis In the West African Dwarf Buck GoatEx-situ Morphological and Morphometric Studies of the Testis In the West African Dwarf Buck Goat

This study was carried out to document ex-situ morphological and morphometric characteristics of the testis in the West African Dwarf (WAD) buck goat. For this aim, 24 post pubertal WAD buck testes were collected at the Ipata Abattoir in Ilorin, Kwara state, Nigeria. Gross morphologic results revealed that WAD testis was ellipsoidal in shape with 2 borders (free and attached), margins (medial and lateral) and similar surfaces (ventral and dorsal). The surfaces were covered by an outer tunica vaginalis and a deep tunica albuginea. Histomorphology showed the testis comprised mostly of rounded and some irregularly shaped seminiferous tubules (ST). Each ST was lined by a basement membrane and a layer of germinal epithelium with lumen filled with spermatozoa surrounded by an adluminal space. Gross morphometric results showed that there were no significant differences in the weight, length, width and height of the right and left testis. Also in the volumes of testes obtained by water displacement method and using the prolate ellipsoid formula. There was a strong correlation between the weights and volumes of testes obtained using these methods. There were significant differences between the volumes of testes obtained by using the prolate spheroid and Lambert formulae, when compared with those obtained by water displacement method respectively. But there was no significant difference in testicular volume obtained by the prolate ellipsoid formula and the water displacement method. Histomorphometric results revealed no significant differences in the seminiferous tubular diameter, seminiferous luminal diameter and germinal epithelia height of the right and left testes respectively. The morphological and morphometric data highlighted in this study would be useful in comparative regional anatomy and researches on the testis of these valuable breed of goats.