Search

Objectives: Fetal magnetic resonance imaging (MRI) plays an increasingly important role in the prenatal diagnosis of gastrointestinal abnormalities. During gestation, the bowel develops T1-weighted hyperintensity due to meconium formation. Currently used T1-weighted sequences are performed in maternal breath-hold (BH) technique, which may take up to 20 s. The free-breathing (FB) T1-weighted 3D radial VIBE (volumetric interpolated breath-hold examination) sequence requires no breath-hold, improving patient comfort. This study aimed to address how well the FB acquisition technique can visualize large bowel structures compared to the routinely performed breath-hold sequence.Methods: Forty-seven fetal MRI studies between 21 and 36 weeks of gestation without abdominal pathologies on prenatal MRI and ultrasound were included. All fetal scans were performed using a Philips Ingenia 1.5 T MRI. Coronal T1-weighted BH and FB sequences without fat suppression were compared. The following acquisition parameters were used (T1, FB): resolution 1.137 mm, 1.004 mm; matrix size 288 × 288, 448 × 448; FOV 328 mm, 450 mm; TR 81-132 ms, 3.47 ms; TE 4.6 ms, 1.47 ms. Due to the necessity of the breath-hold the duration of the sequence could not exceed 20 s (mean duration of the T1-weighted BH sequence 15.17 s, and mean duration of the FB sequence 26.42 s). In all examined fetuses the following structures were evaluated with respect to their visibility (0-not visible, 1-partially visible, 2-clearly visible): rectum, sigmoid, descending, transverse and ascending colon, cecum. Furthermore, motion artifacts were assessed (0-none, 1-intermediate, 2-severe motion artifacts), and the signal intensity (SI) ratio between maternal fat and fetal rectum SI was calculated.Results: No significant differences in the visibility of sigmoid and colon between BH and FB were detected, only the cecum could be seen slightly better (in 29.8 % of cases) using BH technique. Motion artifacts were similar between BH and FB. There was a non-significant SI difference (p = 0.68) in the rectum, with a higher SI in the BH sequence.Conclusions: The FB acquisition technique compared to T1 using BH is equal regarding visibility of bowel structures and artifacts. Due to non-inferiority to the BH technique, the FB sequence is a good alternative in cases where BH cannot be performed. As the FB sequence further allows for thinner slices with a good signal, even small bowel loops may be visualized. [ABSTRACT FROM AUTHOR]

Background and Purpose: On the basis of a single multidynamic multiecho sequence acquisition, SyMRI generates a variety of quantitative image data that can characterize tissue-specific properties. The aim of this retrospective study was to evaluate the feasibility of SyMRI for the qualitative and quantitative assessment of fetal brain maturation., Materials and Methods: In 52 fetuses, multidynamic multiecho sequence acquisitions were available. SyMRI was used to perform multidynamic multiecho-based postprocessing. Fetal brain maturity was scored qualitatively on the basis of SyMRI-generated MR imaging data. The results were compared with conventionally acquired T1-weighted/T2-weighted contrasts as a standard of reference. Myelin-related changes in T1-/T2-relaxation time/relaxation rate, proton density, and MR imaging signal intensity of the developing fetal brain stem were measured. A Pearson correlation analysis was used to detect correlations between the following: 1) the gestational age at MR imaging and the fetal brain maturity score, and 2) the gestational age at MR imaging and the quantitative measurements., Results: SyMRI provided images of sufficient quality in 12/52 (23.08%) (range, 23 + 6-34 + 0) fetal multidynamic multiecho sequence acquisitions. The fetal brain maturity score positively correlated with gestational age at MR imaging (SyMRI: r  =   0.915, P  < .001/standard of reference: r  =   0.966, P  < .001). Myelination-related changes in the T2 relaxation time/T2 relaxation rate of the medulla oblongata significantly correlated with gestational age at MR imaging (T2-relaxation time: r = -0.739, P  = .006/T2-relaxation rate: r  =   0.790, P  = .002)., Conclusions: Fetal motion limits the applicability of multidynamic multiecho-based postprocessing. However, SyMRI-generated image data of sufficient quality enable the qualitative assessment of maturity-related changes of the fetal brain. In addition, quantitative T2 relaxation time/T2 relaxation rate mapping characterizes myelin-related changes of the brain stem prenatally. This approach, if successful, opens novel possibilities for the evaluation of structural and biochemical aspects of fetal brain maturation., (© 2021 by American Journal of Neuroradiology.)

Objectives: Fetal magnetic resonance imaging (MRI) plays an increasingly important role in the prenatal diagnosis of gastrointestinal abnormalities. During gestation, the bowel develops T1-weighted hyperintensity due to meconium formation. Currently used T1-weighted sequences are performed in maternal breath-hold (BH) technique, which may take up to 20 s. The free-breathing (FB) T1-weighted 3D radial VIBE (volumetric interpolated breath-hold examination) sequence requires no breath-hold, improving patient comfort. This study aimed to address how well the FB acquisition technique can visualize large bowel structures compared to the routinely performed breath-hold sequence., Methods: Forty-seven fetal MRI studies between 21 and 36 weeks of gestation without abdominal pathologies on prenatal MRI and ultrasound were included. All fetal scans were performed using a Philips Ingenia 1.5 T MRI. Coronal T1-weighted BH and FB sequences without fat suppression were compared. The following acquisition parameters were used (T1, FB): resolution 1.137 mm, 1.004 mm; matrix size 288 × 288, 448 × 448; FOV 328 mm, 450 mm; TR 81-132 ms, 3.47 ms; TE 4.6 ms, 1.47 ms. Due to the necessity of the breath-hold the duration of the sequence could not exceed 20 s (mean duration of the T1-weighted BH sequence 15.17 s, and mean duration of the FB sequence 26.42 s). In all examined fetuses the following structures were evaluated with respect to their visibility (0-not visible, 1-partially visible, 2-clearly visible): rectum, sigmoid, descending, transverse and ascending colon, cecum. Furthermore, motion artifacts were assessed (0-none, 1-intermediate, 2-severe motion artifacts), and the signal intensity (SI) ratio between maternal fat and fetal rectum SI was calculated., Results: No significant differences in the visibility of sigmoid and colon between BH and FB were detected, only the cecum could be seen slightly better (in 29.8 % of cases) using BH technique. Motion artifacts were similar between BH and FB. There was a non-significant SI difference (p = 0.68) in the rectum, with a higher SI in the BH sequence., Conclusions: The FB acquisition technique compared to T1 using BH is equal regarding visibility of bowel structures and artifacts. Due to non-inferiority to the BH technique, the FB sequence is a good alternative in cases where BH cannot be performed. As the FB sequence further allows for thinner slices with a good signal, even small bowel loops may be visualized., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

The osteocyte lacunar-canalicular network (LCN) penetrates bone and houses the osteocytes and their processes. Despite its rather low volume fraction, the LCN represents an outstanding large surface that is possibly used by the osteocytes to interact with the surrounding mineralized bone matrix thereby contributing to mineral homeostasis. The aim of this study was to quantitatively describe such contributions by spatially correlating the local density of the LCN with the mineral content at the same location in micrometer-sized volume elements in human osteons. For this purpose, 65 osteons from the femur midshaft from healthy adults (n = 4) and children (n = 2) were structurally characterized with two different techniques. The 3D structure of the LCN in the osteons was imaged with confocal laser scanning microscopy after staining the bone samples with rhodamine. Subsequent image analysis provided the canalicular length density, i.e. the total length of the canaliculi per unit volume (μm/μm 3 ). Quantitative information on the mineral content (wt%Ca) from the identical regions was obtained using quantitative backscattered electron imaging. As the LCN-porosity lowers the mineral content, a negative correlation between Ca content and network density was expected. Calculations predict a reduction of around -0.97 fmol Ca per μm of network. However, the experiment revealed for 62 out of 65 osteons a positive correlation resulting in an average additional Ca loading of +1.15 fmol per μm of canalicular network, i.e. an accumulation of mineral has occurred at dense network regions. We hypothesize that this accumulation happens in the close vicinity of canaliculi forming mineral reservoirs that can be utilized by osteocytes. Significant differences found between individuals indicate that the extent of mineral loading of the reservoir zone reflects an important parameter for mineral homeostasis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background and Purpose: In subjects with agenesis of the corpus callosum, a variety of structural brain alterations is already present during prenatal life. Quantification of these alterations in fetuses with associated brain or body malformations (corpus callosum agenesis and other related anomalies) and so-called isolated cases may help to optimize the challenging prognostic prenatal assessment of fetuses with corpus callosum agenesis. This fetal MR imaging study aimed to identify differences in the size of the prenatal hippocampus between subjects with isolated corpus callosum agenesis, corpus callosum agenesis and other related anomalies, and healthy controls., Materials and Methods: Eighty-five in utero fetal brain MR imaging scans, (20-35 gestational weeks) were postprocessed using a high-resolution algorithm. On the basis of multiplanar T2-TSE sequences, 3D isovoxel datasets were generated, and both hippocampi and the intracranial volume were segmented., Results: Hippocampal volumes increased linearly with gestational weeks in all 3 groups. One-way ANOVA demonstrated differences in hippocampal volumes between control and pathologic groups (isolated corpus callosum agenesis: left, P = .02; right, P = .04; corpus callosum agenesis and other related anomalies: P < .001). Differences among the pathologic groups were also present for both sides. Intracranial volume and right and left hippocampal volume ratios were different between corpus callosum agenesis cases and controls ( P < .001). When we corrected for intracranial volume, no differences were found between corpus callosum agenesis and other associated anomalies and isolated corpus callosum agenesis (left, P = .77; right, P = .84). Hippocampal size differences were more pronounced at a later gestational age., Conclusions: Callosal agenesis apparently interferes with the normal process of hippocampal formation and growth, resulting in underdevelopment, which could account for certain learning and memory deficits in individuals with agenesis of the corpus callosum in later life., (© 2019 by American Journal of Neuroradiology.)

Objective: Recently, a potentially useful diagnostic approach based on MR diffusion-tensor-imaging (DTI) was reported for the estimation of putative functional placenta tissue (PFPT), thus providing direct information about placental function. Yet, the relation between reduced PFPT and the phenomenon of brain-sparing remains unclear. This study aimed to investigate the relation between brain-sparing and reduced PFPT volume, as found in fetuses with intrauterine growth restriction (IUGR)., Methods: A total of 40 consecutive patients with a US-based diagnosis of placental IUGR were examined using fetal MRI. A control group of 78 patients who received fetal MRI, due to non-placental pathologies, was established. A somatic energy index was calculated as I E= 1-(V brain /V pfpt ) from brain and PFPT volumes measured with DTI in both groups. I E , V pfpt , and V brain were analyzed with respect to the gestational week., Results: V brain corrected for gestational weeks was no different between both groups, while V pfpt was significantly reduced in IUGR patients. I E was significantly different between both groups and indicated a higher V brain at a comparable V pfpt ., Conclusions: Fetuses with IUGR show preserved energetic resources necessary for brain growth. Because I E drops in IUGR more rapidly as pregnancy progresses, depending on V pfpt , I E could prove useful for estimating fetal well-being., (Copyright © 2018. Published by Elsevier B.V.)

The purpose of this article is to provide an overview of the possibilities for fetal magnetic resonance imaging (MRI) in the evaluation of the fetal brain. For brain pathologies, fetal MRI is usually performed when an abnormality is detected by previous prenatal ultrasound, and is, therefore, an important adjunct to ultrasound. The most commonly suspected brain pathologies referred to fetal MRI for further evaluation are ventriculomegaly, missing corpus callosum, and abnormalities of the posterior fossa. We will briefly discuss the most common indications for fetal brain MRI, as well as recent advances.

Purpose: The great auricular nerve (GAN) is a sensory branch of the superficial cervical plexus. While its blockade is an established procedure, little is known about the ultrasound appearance of pathologic conditions of the GAN itself. We, therefore, aimed to evaluate the possibility of the visualization and diagnostic assessment of the GAN along its entire course by means of high-resolution ultrasound (HRUS)., Materials and Methods: To assess the feasibility of visualization, we performed HRUS with an 18 MHz probe, HRUS-guided, fine-needle ink markings and consecutive dissection in six anatomical specimens. Then, we measured the diameter of the GAN in healthy volunteers and finally performed a retrospective review of patients referred for HRUS examinations because of pain within GAN territory between August 1, 2012 and August 1, 2013., Results: The GAN was clearly visible with HRUS from its formation to the final branches, and was marked successfully on both sides in all anatomical specimens (n = 12). The mean average in-vivo was 0.14 cm ± 0.03 (range 0.08-0.2). Seven cases of patients with GAN pathologies of various origins (idiopathic, traumatic, tumorous and iatrogenic) were identified, of which 6 were visible on HRUS and all of which could be confirmed by complete resolution of symptoms after selective HRUS-guided GAN block., Conclusion: This study confirms the reliable ability to visualize the GAN with HRUS throughout its course, both in anatomical specimens and in vivo. The provided cases show that pathologies of the GAN seem to have a variety of causes and may not be rare. We, therefore, encourage the use of HRUS in patients with unclear pain in the auricular, periauricular and posterior-lateral head., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: The long thoracic nerve (LTN) innervates the serratus anterior muscle (SA) which plays an important role in shoulder function. Evaluation of the LTN has so far been restricted to clinical assessment and partly electromyography and neurography. Progress of high-resolution ultrasound (HRUS) increasingly enables visualization of small peripheral nerves and their pathologies. We therefore aimed at (a) clarifying the possibility of visualization of the LTN from its origin to the most distal point in the supraclavicular region visible and (b) developing an ultrasound protocol for routine use. We further present two cases of patients with LTN pathology., Methods: The study consisted of two parts: Part 1 included 4 non-enbalmed human bodies in whom the LTN (n = 8) was located and then marked by ink injection. Correct identification was confirmed by anatomical dissection. Part 2 included 20 healthy volunteers whose LTN (n = 40) was assessed independently by two radiologists. Identification of the LTN was defined as consensus in recorded images., Results: LTN was clearly visible in all anatomical specimens and volunteers using HRUS and could be followed until the second slip of the serratus anterior muscle from the supraclavicular region. In anatomical specimens, dissection confirmed HRUS findings. For all volunteers, consensus was obtained. The mean nerve diameter was 1.6 mm ± 0.3 (range 1.1 - 2.1 mm) after the formation of the main trunk., Discussion: We hereby confirm a reliable possibility of visualization of the LTN in anatomical specimens as well as in volunteers. We encourage HRUS of the LTN to be part of the diagnostic work-up in patients presenting with scapular winging, shoulder weakness or pain of unknown origin., (© Georg Thieme Verlag KG Stuttgart · New York.)

The aim of the present study was to compare the accuracy, precision, and bias of two macroscopic and one histological age at death estimation methods on human teeth. The sample was comprised of 67 permanent teeth, obtained from 37 individuals aged 20-91 years. Age was predicted according to the methods proposed by Lamendin et al. (LAM), Bang and Ramm (BR), and the quantification of tooth cementum annulations (TCA). TCA was found to be most accurate in all age groups. Its mean absolute error of the estimated age was about half as high as the mean absolute error for both LAM and BR. BR achieved approximately the same mean absolute error as TCA for old adults only. LAM displayed the highest precision in the young and the old age group whereas TCA was more precise in the middle age group. TCA was found to be the most precise method when the precision was calculated for all ages. Considering the bias, all methods displayed a tendency to overestimate age in young and to underestimate it in old specimens. The exception to this rule was TCA, which provided unbiased estimates for young adults. The higher accuracy and precision recommends favouring TCA over LAM and BR, provided that the required know-how and equipment are available.

Ultrasound examination of the elbow and hand is invaluable in diagnostics of acute and chronic joint diseases. Ultrasound is a noninvasive, immediately available procedure without radiation, which should be performed after exploration and clinical examination. It cannot, however, replace radiographic examination because the cortical substance represents a barrier for the ultrasound waves so that bony lesions (i.e., intraosseous tumors or osteomyelitis) cannot be detected. In the diagnosis of periarticular soft tissue lesions and intra-articular changes (loose bodies, intra-articular effusion, or synovitis), ultrasound represents an excellent cost-effective method supplying additional information. The sonographic technique is presented with the standard sectional planes according to the directives given by the working group on the musculoskeletal system of the German Society for Ultrasound in Medicine (DEGUM) issued on 20 January 1996.

Aim: The sonographical examination of the ankle was demonstrated in five standard cross-sections presented by the DEGUM (German Society for the Development of Ultrasonography in the Locomotor Apparatus) and compared with corresponding MRI cross-sections., Method: The sonographical examination was done in a real-time method with an ultrasound unit Type Versa (Siemens, Erlangen, Germany) and with a linear transducer (frequency 7.5 Mhz). The MRI tomographies were taken in two planes with the unit Type Magnetom (Siemens, Erlangen, Germany) with a 1.5 Tesla head-coil in T1- and T2-weighted spin echo sequences., Results: Focus on the ventral, lateral and dorsal region provided a good overview of the superior ankle joint and the periarticular soft tissues., Conclusion: Being a cross-sectional method, the sonographical examination of the ankle joint offers additional information with regard to pathological changes of the joint and the periarticular soft-tissues.

Explantation of the Standard sonographic views with corresponding MRI scans: The sonographic examination of the knee joint can supply additional information in many pathological conditions. In the standardised examination, ventral, lateral and dorsal sectional planes are obtained. In addition, special examinations for the anterior and posterior cruciate ligaments and the menisci can be performed. The important anatomic structures as visualised via ultrasound are compared with the corresponding MRI images. Ultrasound offers a safe, inexpensive way for additional imaging of the injured knee.

The sonographic examination of the knee-joint can, in many pathological alterations of the knee-joint, supply additional informations. In the standardized ultrasound examination of the knee-joint ventral and dorsal sectional planes will be adjusted (4, 7, 14, 17). For the examination of the lesions of the anterior cruciate ligament direct adjustment techniques in the aere of origin of the anterior cruciate ligament (15, 16) and indirect examination methods are known (7, 8, 9, 20). While Hien chose a direct medial parapatellaric horizontal sagittal sectional plane in the course of the lig. patellae (8), we carry out our examination in a ventral infrapatellaric sagittal plane. The examinations were conducted with an ultrasound unit of the type Siemens Sonoline SL 2 with a linear transducer with a frequency of 5 MHz without a stand off pad. In the course of a prospective clinical examination an anteromedial test of stability of both knee-joints was conducted on 360 patients with the help of a sonographic Lachman-test. Two examination groups were formed: in group 1 60 patients with a arthroscopically secured lesion of the anterior cruciate ligament were registered and set against 300 probationers with "empty" anamnesis of the knee-joint of group 2. In the group of patients with a cruciate ligament injury a tibia translation of 5.3 mm in the Lachman-test was found; the side difference between the leg injured and the one uninjured amounted to 3.0 mm. In the control group the tibia translation amounted to 2.9 mm with a side difference of 0.9 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

16beta-Hydroxydehydroepiandrosterone (16beta-OH-DHEA) and related C19-steroids have recently been reported to be etiologic in low-renin essential hypertension. The mineralocorticoid potency of 16beta-OH-DHEA and several C19-steroids (16-oxo-A-diol, 16-oxo-testosterone, 16beta-OH-epiandrosterone, 5-androstene-3beta, 16beta,17beta-triol, 19beta-OH-testosterone, 18-OH-DHEA, and 16alpha-OH-DHEA) were investigated in two different rat bioassay systems under a variety of experimental conditions. In all but one instance, only negligible mineralocorticoid activity was observed, usually less than 0.1 per cent that of aldosterone. Since 16beta-OH-DHEA has negligible mineralocorticoid activity in the rat bioassay and the toad bladder assay (as reported by others), does not cause hypertension when injected chronically into the rat, and does not displace aldosterone from its renal receptors, it appears unlikely to be etiologic in low-renin essential hypertension. On the other hand, when 16-oxo-testosterone was injected intraperitoneally instead of subcutaneously, it demonstrated a slight increase in mineralocorticoid activity (from less than 0.1 per cent to 0.2 per cent) which equaled that of 18-hydroxydeoxycorticosterone (18-OH-DOC) injected subcutaneously. Thus, the possibility remains that 16-oxo-testosterone or a closely related metabolite may have sufficient mineralocorticoid activity to be involved in certain forms of hypertension in man.