Undergraduate medical student perceptions and learning outcomes related to anatomy training using Thiel- and ethanol-glycerin-embalmed tissues.

Anatomical dissection is known to serve as an integral tool in teaching gross anatomy, including postgraduate training. A variety of embalming techniques exist, resulting in different haptic and optical tissue properties. This study aimed to objectify learning outcomes and medical student perceptions related to the use of two widely used embalming techniques, namely Thiel and ethanol-glycerin embalming. Between 2020 and 2022, first- and second-year medical students enrolled in the course on topographic anatomy participated in this study. Objective structured practical examinations were carried out for the head, neck, thorax, abdomen, pelvis, and extremity regions following regional dissection just before the oral examinations began. Six to ten numbered tags were marked in prosections of each region in Thiel- and ethanol-glycerin-embalmed specimens. Following the examinations, the students were surveyed regarding the suitability of the two embalming techniques with respect to preservation, colorfastness, tissue pliability, and the suitability in preparing for their anatomy examinations. Consistently higher scores were achieved for the thoracic and abdominal regions in ethanol-glycerin-embalmed specimens when compared to Thiel. No benefit was found for Thiel-embalmed upper or lower extremities. Tissues embalmed with ethanol-glycerin were rated higher for preservation and suitability to achieve the learning objectives, tissue pliability was rated higher for Thiel-embalmed tissues. Ethanol-glycerin embalming appears to offer certain advantages for undergraduate students in recognizing visceral structures, which may align with students' ideas on tissue suitability for their learning. Consequently, the benefits reported for Thiel embalming for postgraduate study unlikely reflect its suitability for novices.

On the added benefit of virtual anatomy for dissection-based skills.

Technological approaches deploying three-dimensional visualization to integrate virtual anatomy are increasingly used to provide medical students with state-of-the-art teaching. It is unclear to date to which extent virtual anatomy may help replace the dissection course. Medical students of Johannes Kepler University attend both a dissection and a virtual anatomy course. This virtual anatomy course is based on Cinematic Rendering and radiological imaging and teaches anatomy and pathology. This study aims to substantiate student benefits achieved from this merged teaching approach. Following their dissection course, 120 second-year students took part in objective structured practical examinations (OSPE) conducted on human specimens prior to and following a course on Cinematic Rendering virtual anatomy. Likert-based and open-ended surveys were conducted to evaluate student perceptions of both courses and their utility. Virtual anatomy teaching was found to be unrelated to improvements in student's ability to identify anatomical structures in anatomical prosections, yielding only a 1.5% increase in the OSPE score. While the students rated the dissection course as being more important and impactful, the virtual anatomy course helped them display the learning content in a more comprehensible and clinically applicable way. It is likely that Cinematic Rendering-based virtual anatomy affects knowledge gain in domains other than the recognition of anatomical structures in anatomical prosections. These findings underline students' preference for the pedagogic strategy of the dissection course and for blending this classical approach with novel developments like Cinematic Rendering, thus preparing future doctors for their clinical work.

Validation Study for Non-Invasive Prediction of IDH Mutation Status in Patients with Glioma Using In Vivo 1H-Magnetic Resonance Spectroscopy and Machine Learning.

The isocitrate dehydrogenase (IDH) mutation status is an indispensable prerequisite for diagnosis of glioma (astrocytoma and oligodendroglioma) according to the WHO classification of brain tumors 2021 and is a potential therapeutic target. Usually, immunohistochemistry followed by sequencing of tumor tissue is performed for this purpose. In clinical routine, however, non-invasive determination of IDH mutation status is desirable in cases where tumor biopsy is not possible and for monitoring neuro-oncological therapies. In a previous publication, we presented reliable prediction of IDH mutation status employing proton magnetic resonance spectroscopy (1H-MRS) on a 3.0 Tesla (T) scanner and machine learning in a prospective cohort of 34 glioma patients. Here, we validated this approach in an independent cohort of 67 patients, for which 1H-MR spectra were acquired at 1.5 T between 2002 and 2007, using the same data analysis approach. Despite different technical conditions, a sensitivity of 82.6% (95% CI, 61.2-95.1%) and a specificity of 72.7% (95% CI, 57.2-85.0%) could be achieved. We concluded that our 1H-MRS based approach can be established in a routine clinical setting with affordable effort and time, independent of technical conditions employed. Therefore, the method provides a non-invasive tool for determining IDH status that is well-applicable in an everyday clinical setting.

Perirectal intraperitoneal splenosis: A case report of MRI with laparoscopic correlation.

Splenosis is a benign acquired condition, which appears after rupture of the spleen and heterotopic auto-transplantation. Mostly found as an incidental finding on cross-sectional imaging, definitive diagnosis is frequently made histologically after resection or tissue sampling. We report a case of a 36-year-old male patient who presented with increased susceptibility to infections, chronic fatigue, and a history of traumatic splenic rupture. Cross-sectional imaging showed perirectal formations within the mesorectal fascia, and extraperitoneal splenosis was suspected. Due to the radiologically unclear entity of the masses, diagnostic laparoscopy with tissue sampling was performed. Intraoperatively the masses turned out to be intraperitoneal. Histological workup showed splenic tissue, consistent with intraperitoneal splenosis after splenic rupture. In this article we want to discuss important imaging findings and their differentials, as well as clinical implications for this rare entity.

Secondary pneumothorax associated with Birt-Hogg-Dubé syndrome: a case report.

Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal-dominant inherited disease. Typical clinical features include skin lesions, pulmonary cysts, and renal tumors. However, the syndrome remains to be underdiagnosed as a result of its heterogeneous clinical manifestation. In this report, we present the case of a 75-year-old male patient who was referred to the emergency department with pneumothorax, leading to the diagnosis of BHDS. Based on characteristic morphologic features, radiologists have the opportunity to propose BHDS as a differential diagnosis. Establishing the diagnosis in a timely manner is crucial, as these patients require lifelong screening examinations for renal cancer.

Incidental imaging findings suggesting Zinner syndrome in a young patient with pulmonary embolism: A case report.

A triad of seminal vesical cyst, ipsilateral renal agenesis and ipsilateral ejaculatory duct obstruction is known as Zinner Syndrome. First described in 1914, only about 200 cases have been reported in literature. Usually it stays undiagnosed until the second to third decade of life due to lack of symptoms or nonspecific symptoms such as lower urinary tract symptoms, dysuria or painful ejaculation. In this report we present the case of a 22-year-old patient with a Zinner syndrome as an incidental finding and underlie a review of literature to show the main clinical and imaging implications.

Leveraging medical imaging for medical education - A cinematic rendering-featured lecture.

BACKGROUND: The integration of medical imaging into anatomical education offers advantages in understanding and learning. However, spatial orientation with conventional (2D) imaging data is challenging, and the students' ability to imagine structures in three dimensions is individual. In addition, the quality of current volume rendering methods is limited. OBJECTIVE: We tested Cinematic Rendering (CR), a novel visualization technique that provides photorealistic volume rendering, in the setting of an interactive anatomy lecture with first-year undergraduate medical and dental students. Our goal was to estimate the acceptance and positive effects CR adds to the subjects. METHODS: A total of 120 students were surveyed with specifically designed self-assessment questionnaires on the use of CR as a tool in anatomical education. RESULTS: Of 120 participating students (87 medical and 33 dental) a large majority of 95.9% (Q3) experienced CR as helpful to understand anatomy better. Overall a large majority of the students experienced CR as helpful for learning and understanding, 85% saw an improvement in anatomical education through the integration of CR (Q3-6) and could also imagine using CR as a self-study tool on an electronic device. CONCLUSION: Our undergraduate medical and dental students experienced CR as a beneficial tool for anatomical education in the chosen setting (lecture) and see further opportunities for the sensible use of this technique. Future research on the topic should include other application possibilities as well.

18F-Fluorocholine, 18F-FDG, and 18F-Fluoroethyl Tyrosine PET/CT in Parathyroid Cancer.

We report on a 71-year-old woman presenting with biochemical features indicating recurrent disease in long-term follow-up of left-sided parathyroid carcinoma. She had undergone several surgical procedures including total thyroidectomy, partial resection of the esophageal wall, and curative neck radiation 12 years previously. PET/CT using F-fluorocholine revealed high uptake in local relapse in the lower neck, comparable to F-FDG, whereas only faint uptake was observed with F-fluoroethyl tyrosine. As shown in this case, imaging with FDG and F-fluorocholine is feasible in (recurrent) parathyroid carcinoma and clearly superior to F-fluoroethyl tyrosine.

Capillary telangiectasias of the pons. Does diffusion-weighted MR increase diagnostic accuracy?

BACKGROUND AND PURPOSE: Capillary telangiectasias are benign lesions of the brainstem which are sometimes difficult to distinguish from other lesions in standard MRI. The purpose of this study was to evaluate if diffusion-weighted imaging (DWI) could help to improve diagnostic accuracy. METHODS: 148 MR examinations of patients with pontine lesions were evaluated retrospectively and revealed capillary telangiectasia (n=18), presumed microvascular disease (n=20), encephalitis disseminata (n=21), pontine myelinolysis (n=16), tumor (n=20), acute infarction (n=20), subacute infarction (n=13) and chronic infarction (n=20). All patients were examined using identical measurement parameters for DWI, Fluid attenuated inversion recovery, T2-weighted turbo spin-echo, and T1-weighted spin-echo before and after application of contrast agent in transverse orientation. RESULTS: All capillary telangiectasias showed low signal intensity in DWI and significant contrast enhancement after application of gadolinium. Hypointense signal on DWI was very rare for the remaining lesions: only 1 pontine myelinolysis, 1 tumor, 4 subacute infarctions, and 19 chronic infarctions also revealed low signal intensity on DWI. The combination of high signal intensity on T1-weighted post-contrast images and low signal intensity on DWI was found for all capillary telangiectasias, but only for 1/20 tumor and for 4/13 subacute infarctions. These lesions could be differentiated by their clinical course and/or MRI follow-up examinations. The results of the visual assessment were confirmed by quantitative evaluation. CONCLUSION: DWI seems to be a useful adjunct for the diagnosis of capillary telangiectasias which will facilitate the differential diagnosis concerning tumorous, inflammatory and ischemic lesions.

Cerebral cavernous malformations associated with venous anomalies: surgical considerations.

OBJECTIVE: Once thought to be rare entities, mixed cerebrovascular malformations with pathological features of more than one type of malformation within the same lesion are now being recognized with increasing frequency. Their identification generates several hypotheses about common pathogenesis or causation-evolution among different types of lesions and leads to controversial discussion on therapeutic strategies. METHODS: Fifteen patients drawn from a consecutive series of 58 patients harboring cavernous malformations (25.9%) were found to have an associated venous malformation (VM). Three (33.3%) of the first 9 patients, in whom the large draining vein of the VM had been left untouched at previous interventions, developed recurrent and/or de novo lesions. RESULTS: Histopathological analysis, interestingly, revealed that the new lesions were different in nature (three arteriovenous angiomas in two patients, a capillary telangiectasia in one patient). During extirpation of the new malformation, the draining vein of the VM in these three patients could be coagulated without any adverse events. Coagulation and dissection of the draining vein of the associated VM was performed in six more patients of our series, and this has prevented development of new lesions up to now. CONCLUSION: Our results are in favor of the hypothesis that the draining vein of a VM is the actual underlying abnormality of mixed vascular malformations. Causing flow disturbances and having the potential for hemorrhages, the VM seems to promote the development of new adjacent malformations. Thus, permanent cure of associated malformations might depend on the surgical treatment of the VM. We present a preliminary personal series and a thorough review of the literature.

Accessory nerve to suprascapular nerve transfer to restore shoulder exorotation in otherwise spontaneously recovered obstetric brachial plexus lesions.

OBJECTIVE: A systematic follow-up of infants with an obstetric brachial plexus lesion of C5 and C6 or the superior trunk showing satisfactory spontaneous recovery of shoulder and arm function except for voluntary shoulder exorotation, who underwent an accessory to suprascapular nerve transfer to improve active shoulder exorotation, to evaluate for functional recovery, and to understand why other superior trunk functions spontaneously recover in contrast with exorotation. METHODS: In 54 children, an accessory to suprascapular nerve transfer was performed as a separate procedure at a mean age of 21.7 months. Follow-up examinations were conducted before and at 4, 8, 12, 24, and 36 months after operation and included scoring of shoulder exorotation and abduction. Intraoperative reactivity of spinatus muscles and additional needle electromyographic responses were registered after electrostimulation of suprascapular nerves. Histological examination of suprascapular nerves was performed. Trophy of spinatus muscles was followed by magnetic resonance imaging scanning. The influence of perinatal variables and results of ancillary investigations on outcome were evaluated. RESULTS: Exorotation improved from 70 degrees to functional levels exceeding 0 degrees, except in two patients. Abduction improved in 27 patients, with results of 90 degrees or more in 49 patients. Electromyography at 4 months did not show signs of denervation in 39 out of 40 patients. Intraoperative electrostimulation of suprascapular nerves elicited spinatus muscle reaction in 44 out of 48 patients. Histology of suprascapular nerves was normal. Preoperative magnetic resonance imaging scans showed only minor wasting of spinatus muscles in contrast with major wasting after successful operations. CONCLUSION: An accessory to suprascapular nerve transfer is effective to restore active exorotation when performed as the primary or a separate secondary procedure in children older than 10 months of age. Contradictory spontaneous recovery of other superior trunk functions and integrity of suprascapular nerves, as well as absence of spinatus muscle wasting direct to central nervous changes are possible main causes for the lack of exorotation.

Thrombolysis beyond the guidelines: two treatments in one subject within 90 hours based on a modified magnetic resonance imaging brain clock concept.

BACKGROUND AND PURPOSE: We report the first case of 2 intravenous thrombolysis treatments within 90 hours in a patient with early recurrent stroke. SUMMARY OF REVIEW: A 50-year-old man had improved significantly after intravenous thrombolysis for acute stroke. On the fourth day, he deteriorated dramatically because of recurrent stroke. Evidence of vessel reocclusion and profound perfusion/diffusion mismatch constituted the rationale for a second thrombolysis treatment, which resulted in vessel recanalization and significant neurologic improvement. CONCLUSIONS: The pathophysiological information obtained by multimodal magnetic resonance imaging may suit as a brain clock when repeat thrombolysis treatment is considered for early recurrent stroke.

Cerebral cavernous malformations associated with venous anomalies: surgical considerations.

OBJECTIVE: Once thought to be rare entities, mixed cerebrovascular malformations with pathological features of more than one type of malformation within the same lesion are now being recognized with increasing frequency. Their identification generates several hypotheses about common pathogenesis or causation-evolution among different types of lesions and leads to controversial discussion on therapeutic strategies. METHODS: Fifteen patients drawn from a consecutive series of 58 patients harboring cavernous malformations (25.9%) were found to have an associated venous malformation (VM). Three (33.3%) of the first 9 patients, in whom the large draining vein of the VM had been left untouched at previous interventions, developed recurrent and/or de novo lesions. RESULTS: Histopathological analysis, interestingly, revealed that the new lesions were different in nature (three arteriovenous angiomas in two patients, a capillary telangiectasia in one patient). During extirpation of the new malformation, the draining vein of the VM in these three patients could be coagulated without any adverse events. Coagulation and dissection of the draining vein of the associated VM was performed in six more patients of our series, and this has prevented development of new lesions up to now. CONCLUSION: Our results are in favor of the hypothesis that the draining vein of a VM is the actual underlying abnormality of mixed vascular malformations. Causing flow disturbances and having the potential for hemorrhages, the VM seems to promote the development of new adjacent malformations. Thus, permanent cure of associated malformations might depend on the surgical treatment of the VM. We present a preliminary personal series and a thorough review of the literature.

Importance of T2*-weighted gradient-echo MRI for diagnosis of cortical vein thrombosis.

We examined six patients with isolated venous thrombosis (n = 2), or venous thrombosis combined with sinus thrombosis (n = 4) (CVT). The clinical symptoms were non-specific (acute cephalea, paresis, epileptic seizure, progressive speech disorder). All examinations were performed on a 1.5 T system (Magnetom Symphony, Siemens, Erlangen, Germany), maximum gradient field strength 30 mT/m, minimal gradient rise time 450 micros, according to the following protocol: Transverse T2-weighted turbo spin-echo (TSE), fluid attenuated inversion recovery (FLAIR), T1-weighted spin-echo (SE), before and after administration of contrast medium, T2*-weighted conventional gradient-echo (GRE), T2*-weighted spin-echo echo planar imaging (SE EPI), both without and with diffusion weighting as well as two-dimensional (2D) venous time-of-flight (TOF) MRA. The venous thromboses were best detectable in the T2*-weighted conventional GRE sequence in all patients. In two patients, the CVT was discernible only in this sequence. The sinus thrombosis was well discernible only in the T2*-weighted GRE sequence in only one case; in the remaining cases it was detectable only with difficulty. For these cases, other sequences such as SE, diffusion-weighted, or 2D-TOF-MRA sequence were superior. The T2*-weighted conventional GRE sequence was superior to the T2*-weighted SE EPI sequence in all patients. To sum up, it can be concluded, that T2*-weighted conventional GRE sequences are possibly the best method of detection of acute cortical vein thromboses. Therefore, it seems to be of benefit to integrate a T2*-weighted conventional GRE sequence into the MR-protocol for the diagnosis of isolated cortical vein thrombosis.

Magnetic resonance angiography of the carotid arteries using three different techniques: accuracy compared with intraarterial x-ray angiography and endarterectomy specimens.

PURPOSE: To compare three different magnetic resonance angiography (MRA) techniques with x-ray angiography and endarterectomy specimens. MATERIALS AND METHODS: Twenty-one patients underwent x-ray angiography, three-dimensional time-of-flight (TOF) focusing on the carotid bifurcation, high-resolution (HR) contrast-enhanced (CE) MRA, and time-resolved CE MRA. Stenoses of internal carotid arteries were evaluated by three independent observers on identical projection of x-ray angiography and MRA. Maximum stenosis grades on MRA were assessed additionally and correlated with endarterectomy specimens in 12 cases. RESULTS: Sensitivity for the detection of severe stenoses was excellent (100%) for all MRA techniques, and specificity was superior for three-dimensional TOF (96.7%) compared with HR CE MRA (80.6%) and time-resolved CE MRA (83.9%). The correlation between x-ray angiography and MRA for all stenoses was slightly superior for three-dimensional TOF and HR CE MRA compared with the time-resolved technique (kappa = 0.87 and 0.86 vs. 0.84). The same trend was seen for the interobserver agreement and for the correlation with endarterectomy specimens. Eleven up to 17 stenoses (depending on the MRA technique) were graded higher using additional projections. CONCLUSION: Three-dimensional TOF MRA yielded even more accurate results than HR CE MRA in grading of stenoses near the carotid bifurcation. Therefore, a combination of both methods seems to be advantageous.

Contrast-enhanced MR angiography of peripheral arteries including pedal vessels at 1.0 T: feasibility study with dedicated peripheral angiography coil.

PURPOSE: To prospectively determine feasibility of contrast material-enhanced magnetic resonance (MR) angiography of the peripheral arteries from distal aorta to pedal arteries with a 1.0-T system and a dedicated phased-array coil. MATERIALS AND METHODS: Twenty-seven patients with peripheral arteriosclerotic occlusive disease underwent contrast-enhanced MR angiography with an automatic moving-table technique. In addition, lower-leg and pedal arteries were examined without table movement (hybrid technique). Two radiologists independently reviewed MR angiograms to assess image quality and grade stenosis in 13 segments per leg. Each was blinded to patients' clinical data. Twenty-five of the patients also underwent conventional angiography. Stenosis grade at conventional angiography was assessed by two radiologists in consensus. Interobserver variability for stenosis grade at MR angiography was calculated with Cohen kappa test. Specificity and sensitivity of MR angiography in detection of stenosis of more than 50% and occlusion were calculated for both observers. The study was approved by the local ethics committee. RESULTS: In 14 of the 27 patients, hybrid technique was superior to moving-table technique because there was less venous overlap (11 patients), fewer motion artifacts (one patient), or both (two patients). In nine patients, there was no difference between techniques; in four patients, moving-table technique was superior. Stenosis grade was analyzed in 698 segments with MR angiography and in 638 segments with both conventional and MR angiography. Kappa analysis of interobserver agreement with MR angiography yielded a score of 0.84. For the 638 segments evaluated with both conventional and MR angiography, observers 1 and 2 assigned same grade of stenosis with both modalities in 558 and 555 segments, respectively. Sensitivity for stenoses greater than 50% and occlusion was 94.4% and 91.1% for observers 1 and 2, respectively, and specificity was 90.6% and 91.3%. More distal runoff vessels were shown with MR angiography in seven cases and with conventional angiography in two cases. CONCLUSION: Contrast-enhanced MR angiography of the peripheral vessels with a 1.0-T system and dedicated peripheral angiography coil is feasible, and in some cases, it provides additional information compared with conventional angiography.

Implementation of T2*-weighted MR for multimodal image guidance in cerebral cavernomas.

The aim of this study was to evaluate the feasibility, the safety, and the usefulness of T2*-weighted magnetic resonance (MR) for neuronavigational guidance in patients with cerebral cavernomas. Eight patients with intracerebral cavernomas were operated assisted by T2*-weighted MR image-guidance. The cavernomas were either deep-seated or in eloquent regions. Image fusion of a contrast-enhanced T1-weighted gradient-echo (GRE) sequence with a T2*-weighted GRE sequence was performed via an automated fusion software (StealthMerge). The T2*-weighted images were used to secure complete resection of the cavernoma in all patients and to verify resection of surrounding hemosiderin-stained tissue in epilepsy cases. Furthermore, the multimodal neuronavigational concept included ultrasonography, corticography, and evoked potentials. Postoperative MR excluded any residual malformation in all cases. There was no postoperative morbidity; all epilepsy patients are seizure-free up to now. In our preliminary series, T2*-GRE-guided neuronavigation proved useful for resection control in cavernoma surgery, and we suppose that it will be helpful to clarify the discussion on the value of resection of the surrounding hemosiderin-stained tissue.

MR diagnosis of superficial femoral artery aneurysm, primarily misdiagnosed as soft tissue tumor. A case report.

We report a 84-year-old man with an aneurysm of the superficial femory artery (SFA). Primarily, after B-mode sonography soft tissue neoplasm was suspected and sectional MR imaging was performed for further diagnostics. Because of blood flow related ghost artifacts, sectional MR led to the diagnosis of an partially thrombosed aneurysm without angiography. Initially, the differential diagnosis of an SFA aneurysm, which is extremely rare, has not been considered. Soft tissue neoplasms may have a similar appearance to partially thrombosed aneurysms. This case demonstrate the importance to notice also artifacts in sectional MRI which can give important informations for correct diagnosis.

Peripheral vessels: MR angiography with dedicated phased-array coil with large-field-of-view adapter feasibility study.

At magnetic resonance (MR) angiography with conventional phased-array coils, visualization of the vascular tree from the infrarenal aorta to the pedal arch is not possible in most patients. For this purpose, the authors developed a dedicated adapter with a large field of view that allows coverage of a body length of approximately 1,380 mm. Among five patients with peripheral arteriosclerotic disease, four underwent both conventional angiography and MR angiography. One hundred fourteen vascular segments from the infrarenal aorta to the feet were evaluated. Agreement between findings at conventional angiography and those at MR angiography was 94.7% (108 of 114) for all segments (96.1% [25 of 26] in the abdomen or pelvis, 97.5% [39 of 40] in the thigh, and 91.7% [44 of 48] in the calf or foot).