Evaluation of the plantaris tendon: cadaver anatomy study with ultrasonographic and clinical correlation with tennis leg injury in 759 calves

OBJECTIVE

The role of the plantaris muscle (PM) in the literature is not clear. The objectives of this study were as follows: (1) to study PM at the interface between the medial gastrocnemius and soleus muscle in a cadaveric series, (2) to compare anatomic results with ultrasound (US) in the general population, and (3) to identify the potential role of the PM in the genesis of tennis leg (TL) injury.

METHODS

First, a cadaveric study was undertaken on six cadavers for descriptive and functional PM anatomy. Second, US evaluation was carried out for 670 calves in 335 subjects with no suspicion of a clinical tear in the thigh or calf muscle (group 1) and for 89 calves in 89 patients with tear symptoms (group 2). Study criteria were the presence or absence of PM tendon and the width measurement if present.

RESULTS

The PM was present in all cadavers. Traction on the tendon showed its "limited" mobility due to the connective tissue adherence mentioned with no apparent gliding of PM, promoting TL injury. In US, 37 PM were absent (4.35%) in 23 subjects. PM tendon width measurement of group 1 and group 2 was, respectively, 3.93 + / - 1.10 mm and 3.96 + / - 1.10 mm. No statistically significant differences between width measurements were found according to side (P = 0.74) or group (P = 0.69). Significant differences in width were only found between genders in group 1 (P = 0.014).

CONCLUSION

PM were absent in 4.35% population. The contraction of PM can promote tennis leg injury by increasing the shear forces at the level of the distal inter-aponeurotic region.

Impact of the rise of artificial intelligence in radiology: What do radiologists think?

PURPOSE

The purpose of this study was to assess the perception, knowledge, wishes and expectations of a sample of French radiologists towards the rise of artificial intelligence (AI) in radiology.

MATERIAL AND METHOD

A general data protection regulation-compliant electronic survey was sent by e-mail to the 617 radiologists registered in the French departments of Nord and Pas-de-Calais (93 radiology residents and 524 senior radiologists), from both public and private institutions. The survey included 42 questions focusing on AI in radiology, and data were collected between January 16^th and January 31^st, 2019. The answers were analyzed together by a senior radiologist and a radiology resident.

RESULTS

A total of 70 radiology residents and 200 senior radiologists participated to the survey, which corresponded to a response rate of 43.8% (270/617). One hundred ninety-eight radiologists (198/270; 73.3%) estimated they had received insufficient previous information on AI. Two hundred and fifty-five respondents (255/270; 94.4%) would consider attending a generic continuous medical education in this field and 187 (187/270; 69.3%) a technically advanced training on AI. Two hundred and fourteen respondents (214/270; 79.3%) thought that AI will have a positive impact on their future practice. The highest expectations were the lowering of imaging-related medical errors (219/270; 81%), followed by the lowering of the interpretation time of each examination (201/270; 74.4%) and the increase in the time spent with patients (141/270; 52.2%).

CONCLUSION

While respondents had the feeling of receiving insufficient previous information on AI, they are willing to improve their knowledge and technical skills on this field. They share an optimistic view and think that AI will have a positive impact on their future practice. A lower risk of imaging-related medical errors and an increase in the time spent with patients are among their main expectations.

An anatomical study of the indirect tendon of the rectus femoris using ultrasonography

The aim of this study was to demonstrate that ultrasound can allow a precise assessment of the indirect tendon of the rectus femoris using a new lateral approach.

METHODS AND MATERIALS

Four hips were dissected for the anatomical study of the proximal rectus femoris insertions. Under ultrasonographic guidance, spinal needles piercing the direct tendon were placed in the indirect tendon, following by dissection. Then, high-resolution ultrasound was performed in 20 volunteers with assessment of the indirect tendon of the rectus femoris.

RESULTS

At dissection, the spinal needles were located in or immediately adjacent to the indirect tendon, thus confirming that it was correctly depicted by ultrasound. The indirect tendon could be identified in each cadaver and each volunteer with ultrasound. The optimal position of the probe to allow assessment of the indirect tendon could be defined. No significant changes in the appearance or thickness of the tendon could be observed.

CONCLUSION

The results of our study showed that the indirect tendon of the rectus femoris muscle can be clearly depicted by sonography in healthy adult subjects. The potential applications of this new use of sonography must now be confirmed by clinical studies.

KEY POINTS

• The anatomy of the proximal rectus femoris is reviewed • Until now, sonography was limited for assessing direct and conjoined tendons • The indirect tendon can be clearly depicted by sonography • A new lateral approach for studying the indirect tendon is described.

Pisotriquetral joint disorders: an under-recognized cause of ulnar side wrist pain

Pisotriquetral joint disorders are often under-recognized in routine clinical practice. They nevertheless represent a significant cause of ulnar side wrist pain. The aim of this article is to present the main disorders of this joint and discuss the different imaging modalities that can be useful for its assessment.

Anatomic and CT scan assessment of Teres Minor: a new index of trophicity

INTRODUCTION

The present study reports the development of a CT assessment protocol for Teres Minor (TM) trophicity.

HYPOTHESIS

Quantitative reproductible Terres Minor assessment on CT estimates the influence of muscle trophicity on the clinical and radiological results of palliative treatment of irreparable rotator cuff tear.

MATERIALS AND METHOD

An anatomic study of 30 cadaveric shoulders confirmed a constant anatomic relation between Terres Minor and the inferior pole of the glenoid cavity. This landmark was used to develop a novel CT assessment of TM trophicity.

RESULTS

The CT assessment showed excellent inter- and intra-observer reproductibility. The protocol defines a trophicity index, T2/G (T2 being TM thickness on axial CT slice, and G the maximum glenoid cavity thickness on axial slice), enabling reproductible TM analysis on preoperative arthro-CT.

CONCLUSION

The study validated the CT protocol, allowing application in pre- and postoperative assessment of irreparable rotator cuff tear.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Radiographic anatomy of the intervertebral cervical and lumbar foramina (vessels and variants)

The intervertebral foramen is an orifice located between any two adjacent vertebrae that allows communication between the spinal (or vertebral) canal and the extraspinal region. Although the intervertebral foramina serve as the path traveled by spinal nerve roots, vascular structures, including some that play a role in vascularization of the spinal cord, take the same path. Knowledge of this vascularization and of the origin of the arteries feeding it is essential to all radiologists performing interventional procedures. The objective of this review is to survey the anatomy of the intervertebral foramina in the cervical and lumbar spines and of spinal cord vascularization.

Experimental study of the expansion dynamic of 9 mm Parabellum hollow point projectiles in ballistic gelatin

We study in this paper the expanding behaviour of hollow point 9 mm Parabellum projectiles (Hornady XTP(®) and Speer Gold Dot(®)). We defined a deformation rate that takes into account both the diameter increase and the length reduction. We plotted the behaviour of this parameter versus impact velocity (we refer to this curve as the expanding law). This expanding law has been plotted for different gelatin weight ratios and different gelatin block lengths. We completed our experiments with a set of high speed movies in order to correlate the deceleration to the state of expansion and size of the temporary cavity. Our results pointed out that full expansion is reached shortly after the projectile fully penetrates the gelatin. This result shows that the key point to accurately simulate human body interaction with a hollow point projectile is to accurately simulate the interface (skin, skull, clothes thoracic walls). Simulating accurately organs is only an issue if a quantitative comparison between penetration depths is required, but not if we only focus on the state of expansion of the projectile. By varying the gelatin parameters, we discovered that the expanding law exhibits a velocity threshold below which no expansion occurs, followed by a rather linear curve. The parameters of that expanding law (velocity threshold and line slope) vary with the gelatin parameters, but our quantitative results demonstrate that these parameters are not extremely critical. Finally, our experiments demonstrate that the knowledge of the expansion law can be a useful tool to investigate a gunshot in a human body with a semi-jacketed projectile, giving an estimation of the impact velocity and thus the shooting distance.

[Plain radiographs of the wrist and hand]

The purpose of this review is to describe the value of the different radiographic projections of the wrist and hand, provide criteria for quality control and key interpretation points. Plain radiographs of the hand and wrist are still, in this era of cross-sectional imaging, of great importance in the assessment and understanding of bone and joint disorders, particularly in the setting of trauma. Indeed postero-anterior and lateral views have to be completed with additional projections depending on the suspected lesion and clinical presentation.

In vivo MR tractography of thigh muscles using diffusion imaging: initial results

The aims of this preliminary study were (1) to demonstrate the feasibility of providing in vivo 3D architecture of human thigh muscles using tractography on a 1.5T magnet, and (2) to assess the value of tractography images to obtain averaged microstructural parameters, i.e., the fractional anisotropy (FA) and the mean apparent diffusion coefficient (ADC), over the whole thigh. Five healthy volunteers were included in this study. Their right thighs were imaged using diffusion tensor imaging and gradient-echo T2* sequences. Muscular tractography was performed on each muscle. MR tractography provided a good approach of the muscle shape and of the orientation of the muscle fibers. There was no aberration in the color-encoding scheme nor in the luminosity assigned to each fiber. In contrast, tendons were not drawn in any of the muscles studied. FA values ranged from 0.27 to 0.38. Mean ADC values ranged from 0.76 to 0.96 x 10(-3) mm2/s. Our study demonstrated the feasibility of providing in vivo 3D architecture of human thigh muscles using tractography on a 1.5T magnet, and of determining muscular microstructural parameters (FA and ADC). Musculoskeletal radiologists should be aware of these new developments that may provide complementary information on muscles to the usual sequences.

Ultrasound of the nerves of the knee region: Technique of examination and normal US appearance

The diagnosis of disorders of the peripheral nerves (PN) has traditionally been based on clinical and electrophysiological data since nerve tissue cannot be visualized on standard radiographs. More recently, however, nerve structures have been evaluated with magnetic resonance imaging (MRI) and ultrasound (US). The former modality is expensive and not available in all institutions. There are also some contraindications to its use, and the assessment of long nerves can be time-consuming since different coils must be used. Thanks to recent advances in sonographic software and hardware, US can now be used for in-depth assessment of the PN of the upper and lower limbs.Most knee disorders involve lesions to the cruciate ligaments and/or the menisci, which are difficult to evaluate with US. However, similar symptoms may be caused by compression of one or more nerves in the knee region or intrinsic disorders involving these structures. Because of their superficial positions, the nerves around the knee can be clearly visualized with US. A thorough knowledge of the normal anatomy of this region and a careful scanning technique are essential for a successful diagnostic US examination. In this article, we will review the normal gross and microscopic anatomy of the nerves in the knee region, the US technique used for their examination, and their normal US appearance.

The female inferior hypogastric (= pelvic) plexus: anatomical and radiological description of the plexus and its afferences—applications to pelvic surgery

AIM OF THE STUDY

We wanted to determine the anatomical features of the inferior hypogastric plexus (IHP), and the useful landmarks for a safe surgical approach during pelvic surgery.

MATERIALS AND METHODS

We dissected the IHP in 22 formolized female anatomical subjects, none of which bore any stigmata of subumbilical surgery.

RESULTS

The inferior hypogastric plexus (IHP) is a triangle with a posterior base and an anterior inferior top. It can be described as having three edges and three angles; its inferior edge stretches constantly from the fourth sacral root to the ureter's point of entry into the posterior layer of the broad ligament; its cranial edge is strictly parallel to the posterior edge of the hypogastric artery, along which it runs at a distance of 10 mm; its posterior (dorsal) edge is at the point of contact with the sacral roots, from which it receives its afferences. They most frequently originate from S3 or S4 (60%) and then, in one or two branches, often from S2 (40%), never from S1 and in exceptional cases from S5 (20%). There are sympathetic afferences in 30% of cases, usually through a single branch of the second, third or fourth sacral ganglion. All IHPs have at least one sacral afference and sometimes there may be up to three afferences from the same sacral root. Its dorsal cranial angle, which is superior, comes after the SHP (hypogastric nerve or presacral nerve filament); its anterior inferior angle is located exactly at the ureter's point of entry into the posterior layer of the broad ligament. This is the top of the IHP; its posterior inferior angle is located at the point of contact with the fourth sacral root. At its entrance at the base of the parametrium the pelvic ureter is the anterior, fundamental positional reference for the IHP. The vaginal efferences come out of the top of the IHP through branches leading to the bladder, the vagina and the rectum, which originate through two trunks exactly underneath the crossing point of the ureter and the uterine artery: (i) one trunk leading to the bladder runs along and underneath the ureter and divides into two groups, which are lateral and medial, trigonal. (ii) the trunk leading to the vagina runs along the inferior edge of the uterine artery. At the point of contact with the lateral edge of the vagina, it splits into two groups: anterior thin and posterior voluminous. Some of its branches perforate the posterior wall of the vagina and are distributed to the rectovaginal septum in a tooth comb pattern. The inferior branches, which emerge from the inferior edge of the IHP, reach the rectum directly. The dissection of the 22 specimens allowed us to describe three efferent plexuses: a vaginal rectal plexus, a vesical plexus and a inferior rectal plexus. So the IHP's anterior, fundamental positional reference is the pelvic ureter at the point where it enters at the base of the parametrium, then at the crossing point of the uterine artery. The ureter is the vector for vesical efferences, the uterine artery is the vector for vaginal efferences, which are thus sent into the vesicovaginal septum and the rectovaginal septum. This surgical point of reference is of vital importance in nerve sparing during the course of a simple or extended hysterectomy. Any dissection carried out underneath and outside of the ureter inevitably carries a risk of lesions to its efferent, lateral vesical or medial, rectovaginal fibres.

Multimodal visualization interface for data management, self-learning and data presentation

A multimodal visualization software, called the Data Manager (DM), has been developed to increase interdisciplinary communication around the topic of visualization and modeling of various aspects of the human anatomy. Numerous tools used in Radiology are integrated in the interface that runs on standard personal computers. The available tools, combined to hierarchical data management and custom layouts, allow analyzing of medical imaging data using advanced features outside radiological premises (for example, for patient review, conference presentation or tutorial preparation). The system is free, and based on an open-source software development architecture, and therefore updates of the system for custom applications are possible.

Les tendons : lésions inflammatoires et dégénératives

Tendons may be affected by a variety of pathologic conditions, including those caused by overuse and inflammatory diseases. Sonography is a very sensitive means of detecting tendonous pathology because of its spatial resolution and its comparative and dynamic capabilities. Moreover its wide availability makes it the preferred first-line imaging modality in these cases. This paper reviews the inflammatory and degenerative conditions that may involve the tendons and their sonographic appearances.

Normal anatomy of the heel entheses: anatomical and ultrasonographic study of their blood supply

The purpose of this study was first to determine the normal blood supply of the heel entheses with cadaver injection, and second, to identify by means of ultrasound (US) this blood supply in healthy volunteers before and after the intravenous injection of a US contrast agent (SonoVue). Twenty cadaver lower limbs were cut into sagittal, coronal, or axial sections after the injection of a red-colored gelatin solution. Ten anatomical samples were selected for histology. Then 10 healthy volunteers were enrolled in a contrast-enhanced ultrasonography study (CUS). Calcaneal tendon and plantar aponeurosis entheses were studied first without any contrast-agent (B-mode, power Doppler). A single dose (2.4 ml) of the contrast agent was then administered for studying each enthesis of the right foot. The operators had to look for blood flow within the entheses and in the adjacent soft tissues. Anastomotic transverse branches were seen macroscopically at the back of the calcaneal tendon, giving some capillaries penetrating the enthesis. None of these vessels could be seen with CUS. In contrast, a high-density vascular network could be detected in Kager's triangle with CUS. No blood vessel could be seen within the plantar aponeurosis enthesis, either macroscopically or microscopically. No evidence of entheseal vascularization was found with any contrast-enhanced imaging technique. Inferior branches of the lateral plantar artery were seen on coronal and sagittal sections of the hindfoot, and could be detected with CUS. These arterioles were running toward the anterior aspect of the calcaneal tuberosity, near the plantar aponeurosis insertion. In conclusion, no vascularization was detected with CUS at the cortical bone insertion of normal heel entheses. However, some vascularization could be seen in the immediate vicinity of heel entheses. The latter feature has to be kept in mind, as it may represent a pitfall for the diagnosis of early inflammatory changes in patients, especially those with seronegative spondylarthropathies.

The communicating branches between the sural and superficial peroneal nerves in the foot: a review of 55 cases

The rich sensory innervation of the ankle and foot is manifest through the numerous communicating branches linking the neural trunks, particularly the superficial peroneal and sural nerves on the anterolateral aspect of the hindfoot. The 35 communicating branches seen in 55 dissections (58%) were proximal in half of the cases, lying in the malleolar and lateral tarsal regions, and distal in the other half, in the metatarsal region. The communicating branch was straight in 25 cases and curved in 11. The average distances of the communicating branch from the crest of the lateral malleolus and the tubercle of the 5th metatarsal was 4.7 and 4.1 cm, but there was a wide range of values. We believe that stretching of the proximal communicating branch during forced inversion of the ankle and/or foot or during fractures of the calcaneus or direct injury in surgical approaches or arthroscopy of the ankle may lead to unexplained pre- and submalleolar pain. Advances in modern imaging may allow recognition of these branches and guidance of infiltration and even neurolysis in cases of failure of conservative treatment.

Anatomic and biometric study of the acromioclavicular joint by ultrasound

The aim of this study was to describe the normal ultrasound anatomy of acromioclavicular joint (ACJ) and to establish ultrasound biometric criteria of this joint. Thirty healthy volunteers (16 men, 14 women) underwent a bilateral ultrasound examination of the ACJ in both planes (superior, anterosuperior) by two different observers. Six measurements were evaluated on the ACJ. The morphological appearance was also studied. Five morphological types of the ACJ were identified. No significant biometric difference was found between the observers, the planes, the dominant and the non-dominant side, and between men and women (except for the deep joint space distance). However, the variability of the ACJ made this biometric study difficult. The maximum distance between the joint capsule and the deep joint space through the superior plane, seemed to be a reproducible measurement with the best confidence interval.

The fibrocartilaginous sesamoid: a cause of size and signal variation in the normal distal posterior tibial tendon

The aim of this study was to investigate the presence of fibrocartilage within the distal posterior tibial tendon (PTT) before its division correlating with size and signal variation on MR images through a radio-anatomic and pathologic study. Eight fresh cadaveric feet underwent MR imaging were cut into 4-mm slices in the axial plane. The PTT specimens were harvested at the tendon distal portion before its division and sent to pathology. Thirty-three asymptomatic subjects underwent axial double-echo turbo-spin-echo MR imaging. Proximal and distal PTT signal and diameter were evaluated. In cadavers, every PTT flared distally. Intratendinous fibrocartilage and ossified sesamoid were found in, respectively, 87.5 and 12.5% of the cases. Distal PTT flaring was demonstrated in 100% of the asymptomatic subjects (mean diameter 8 mm). An intratendinous high signal intensity on proton-density-weighted images and sesamoid bone were evidenced in, respectively, 36 and 33% of the cases. Proximally, PTT presented a 4-mm mean diameter and was hypointense in 100% of the cases. Only one accessory navicular bone was detected. Laterally off-centered increased intratendinous signal intensity as well as PTT distal widening with otherwise normal MR imaging features are related to an intratendinous fibrocartilage.

Multi-fasciculated anterior talo-fibular ligament: reassessment of normal findings

The aims of this study were to (a) provide an accurate description of the anterior talo-fibular ligament (ATFL) multifasciculated feature by means of cadaver study, and (b) to further delineate contour and signal variations on MR images related to this feature in a group of asymptomatic subjects. After MR imaging, three cadaveric feet were frozen and cut in the coronal plane. The ATFL were harvested and sent to pathology. Another cadaveric foot was dissected. The MR imaging was performed in 3 healthy volunteers and 19 patients without pathology of the ATFL. For both cadaveric feet and subjects, MR imaging protocol consisted of axial and coronal proton-density (PD) and T2-weighted turbo-spin-echo (TSE) sequences (TR/TE: 3500 ms/17-119 ms). On MR images, ATFL signal and fascicle numbers were assessed, respectively, in the axial and coronal planes. Gross anatomy and pathology confirmed the ATFL bifasciculated aspect. On cadaveric coronal MR images, 3 of 4 ATFLs were bifasciculated and one of four was striated. On patients' coronal MR images, 2 of 22 of the ATFL were monofasciculated, 12 of 22 bifasciculated, and 8 of 22 striated. On axial MR images, 16 of 22 of the ATFL demonstrated a low signal intensity and 8 of 22 an intraligamentous subtle increased signal intensity. Two of 22 of the ATFL had contour irregularities. Isolated anterior talo-fibular intraligamentous signal abnormalities or contour irregularities on axial PD and T2-weighted MR images with an otherwise normal ATFL aspect on coronal MR images and no other MRI criteria for ankle sprain may reflect normal anatomy.

[Value of US imaging of metacarpophalangeal joints in patients with early rheumatoid arthritis]

Technological advances in the field of ultrasound imaging may have, especially in metacarpophalangeal joints, an impact on decision making in patients with early rheumatoid arthritis. First, the normal anatomy of the metacarpophalangeal joints is briefly reviewed. Then, the authors describe the main ultrasound imaging findings of early RA. The role of ultrasound imaging in the assessment of therapeutic response as well as the benefit of microbubble ultrasound contrast agents are considered.

The inferior hypogastric plexus (pelvic plexus): its importance in neural preservation techniques

The progress in the surgery of male neurological cancers relies on the anatomico-surgical approach to the pelvic neural structures. The objective of our study was to provide a better understanding of the inferior hypogastric plexus (IHP) and its anatomical relationships in order to spare it during radical prostatectomy. Fifteen male formalin-preserved cadavers which had no sub-umbilical scar were used. In five subjects, the superior hypogastric plexus (SHP) and the pre-sacral plexus were displayed then the IHP and its sacral afferents (pelvic splanchnic nerves or erector nerves of Eckhardt) were dissected out. Serial sections of the IHP were then studied in ten subjects. This allowed its identification on certain imaging sections obtained in pelvic tumor pathology and these made up the "reference cuts". The IHP lies within a fibro-fatty plate which is flat, rectangular, sub-peritoneal, sagittal and symmetrical. It arises at the level of the intersection between the vas deferens and the terminal pelvic ureter and follows the postero-lateral aspect and circumvolutions of the seminal vesicle, with which there is a plane of surgical cleavage. The seminal vesicle is, therefore, an essential landmark for this neural structure. The plane of this cleavage may be used in pelvic cancer surgery. The safest technical means of respecting sexual function and the integrity of the IHP is to keep it at a distance. The preservation of a lateral layer of the seminal vesicle is probably a method of limiting these complications as long as this does not conflict with the oncological clearance. An irregular communicating branch was found in one of five cases between the IHP, the sacral plexus and the pudendal nerve. This communicating branch lay immediately behind the intersection between the vas deferens and the ureter in the sacral concavity. It overhangs the IHP in the seminal vesicle. Impotence remains a frequent complication after radical prostatectomy. The methods of neural preservation at the prostatic apex are known but neural preservation should also be carried out posteriorly at the lateral pole of the seminal vesicle. The possibility of posterior neural preservation may be assessed pre-operatively by study of the "reference sections". The cleavage plane between the seminal vesicle and the IHP may be used intra-operatively to spare the IHP. The cavernous nerve in particular emerges at the antero-inferior border of the IHP before running along the postero-lateral aspect of the prostate. It therefore passes in contact with the seminal vesicle and may as a result be injured during radical prostatectomy with vesiculectomy. A proximal communicating branch between the IHP and the pudendal nerve is irregular. Such communicating branches may explain a better recovery of sexual function in curative neurological cancer surgery. The essential relationship of the IHP is with the seminal vesicle. The two are in tight contact and the seminal vesicle has a true plane of surgical cleavage with IHP. The risk of injuries to the posterior erectile mechanisms can be reduced either by using the cleavage plane between the IHP and seminal vesicle or by leaving a layer of the seminal vesicle when the oncological conditions allow. During celio-surgery, the operator must be careful to retract the little bands of the seminal vesicle and divide the fibrous and vascular tracts which tighten during this maneuver. During an abdominal approach, dissection of the seminal vesicle takes place at the bottom of a real pit. The operator must carry out the division leaving a layer of the seminal vesicle in place rather than trying to extract all the seminal vesicle by placing the forceps blindly. This maneuver is naturally dependent on the oncological situation. The anatomical confirmation of a regular or irregular proximal or distal communicating branch between the IHP and the pudendal nerve is probably an explanation for the sometimes uncertain results of new techniques of neural preservation in curative cancer surgery.

Lumbar spinal ganglia enhancement after gadolinium chelate administration: a radio-histological correlation

The aim of the present study was to assess the frequency of enhancement of lumbar spinal ganglia after Gadolinium chelate injection in patients without radiculopathy, and to correlate the enhancement with histology. This study is based on the analysis of MR lumbar examinations conducted on 18 patients without radicular symptoms, or previous surgery of the lumbar spine, or disease of the nervous system. The patients were imaged with a 1.5 T unit. Sagittal images were first obtained with a T1-weighted turbo spin-echo. Axial and sagittal images were then obtained with a T1-weighted turbo spin-echo, fat-saturated sequence after Gadolinium intravenous injection from the T12/L1 to the L5/S1 level. All 180 spinal ganglia demonstrated an important and homogeneous enhancement after Gadolinium injection. Four spinal ganglia obtained by dissection from four different fresh cadavers were studied by light microscopy to determine the potential relationship between contrast enhancement and presence and topography of vessels within the spinal ganglia. Vessels were particularly abundant at the peripheral zone of the spinal ganglia. The post-contrast enhancement of the spinal ganglia after Gadolinium administration has to be known and may be explained by the microvasculature pattern.

Transpedicular screw placement: image-guided versus lateral-view fluoroscopy: in vitro simulation

STUDY DESIGN

In vitro evaluation of monitoring screw placement using an image-guided system compared with the routine use of an image intensifier.

OBJECTIVES

To compare a new computer-guided method of monitoring pedicle screw placement with a well-known method of monitoring using an image intensifier, using measurements of screw placement time and accuracy.

SUMMARY OF BACKGROUND DATA

Pedicle screw placement relies on the identification of anatomic landmarks for the point of entry of the pedicle. The direction and depth of screw penetration are guided by an intraoperative lateral-view image intensifier. The use of frameless stereotaxy for computer-aided pedicle screw placement may increase the accuracy and safety of the screw insertion. To the authors' knowledge, there are no published data comparing these systems on the basis of operative time and screw placement accuracy.

METHOD

Eight human cadaveric sections of five vertebrae each were used for an in vitro simulation of pedicle screw placement. Four spine surgeons were chosen to simulate the transpedicular screw placement. Each surgeon placed one screw into each pedicle of two spine sections (10 vertebrae, 20 screws). The surgeon was assisted by the lateral-view image intensifier on one spine section and by the navigational system on the second one. The four surgeons placed 80 pedicle screws. Forty screw placements were monitored by fluoroscopy and 40 by the image-guided navigational system. The time spent to place one screw was recorded, as well as the remarks by each surgeons on each method. Spines were rescanned, and the positions of the screws were compared between the group on which the image intensifier has been used and the group on which the navigational system had been used.

RESULTS

In the image-guided technique group, one thoracic screw disrupted the lateral cortex of the pedicle, the average distance to the anterior wall of the body was 5 mm, and the average time for the insertion of one screw was 13.5 minutes. In the other group, two screws disrupted the inner cortex of a thoracic pedicle, the average distance to the anterior wall was 10.7 mm, and the average time for the insertion of one screw was 4 minutes.

CONCLUSIONS

In vitro computer-aided pedicle screw insertion is more accurate than lateral-view fluoroscopy in the thoracic spine. The main disadvantage is the time consumption compared with that required by lateral-view fluoroscopy. The total time of the surgical operation should be decreased with the future development of these techniques.

Origin and make up of the human sural nerve

The dissection of 37 cadavers has shown that in only a third of cases, the sural nerve comes from the communication between the medial cutaneous nerve, derived from the tibial nerve, and the communicating branch of the lateral cutaneous nerve of the leg which comes from the lateral popliteal nerve. The communication is most often at the junction between the proximal two-thirds and distal third of the leg, on average 2 mm below the transverse crease of the popliteal fossa. The medial cutaneous nerve was absent in only one case. On the other hand, in 11 cases the lateral cutaneous nerve or its communicating branch was missing. In 12 cases without any anastomoses, the route of the sural nerve was followed by the medial cutaneous nerve of the leg in 9 cases and by the lateral cutaneous nerve in 3 cases. The majority of branches to the proximal half of the calf came from the lateral cutaneous nerve. In the lower part of the leg, the sural nerve and/or the medial cutaneous nerve gave numerous branches to the Achilles' tendon and to the integuments of the lateral aspect of the heel and lateral malleolus.

[Ulnar nerve compression and pseudoarthrosis of the medial metacarpal bases]

A case of compression of the deep branch of the ulnar nerve associated with pseudarthrosis of the base of the fifth metacarpal and the upper shaft of the fourth metacarpal is reported. The delayed procedure consisted in volar decompression of the ulnar nerve by dividing the pisi-hamate ligament and plating and grafting of both fractures. The patient achieved marked improvement four weeks post-operatively and had complete functional recovery at follow-up of 16 years after injury without narrowing of the hamato-metacarpal joint despite synostosis of the bases of the medial metacarpals.

[Relationship between the tendon of the long head of the biceps brachii muscle and the glenoid labrum]

For many authors, the insertion of the long head of the biceps brachii muscle is exclusively or mainly located on the supraglenoid tubercle. The aim of this work was to study the insertion of the long head of the biceps brachii at macroscopic and microscopic examinations. 31 shoulders of macerated cadavers of both sex (age range: 52-92 years) were dissected by a posterior approach in order to study the glenoid labrum and the origin of the long head of the biceps brachii muscle. At macroscopic examination two types of the proximal part of the long head of the biceps brachii were demonstrated: a flattened shape in 84% of the cases and a hemicylindrical shape in 16% of the cases. Four types of origin were demonstrated at dissection: in 64.5% of the cases the tendon inserted mainly on the postero-superior part of the labrum, in 19.4% of the cases the tendon inserted both on the postero-superior and postero-anterior labrum, in 6.4% of the cases it inserted only on the supraglenoid tubercle and in three cases the tendon inserted on the intertubercular groove. The histologic examination performed on 6 superior part of the bicipitolabral complex have all shown that the tendinous fibers blended with the glenoid labrum. The examination performed on an complete labrum demonstrated tendinous fibers within the glenoid labrum up to the junction between the postero-superior and postero-inferior part of the labrum.

Radio-anatomic demonstration of the vertebral lumbar venous plexuses: an MRI experimental study

The aim of this study was to provide a basis of knowledge of the anatomy of the venous plexuses in the lumbar spine both in anatomical slices and in MR images in order to help the analysis of these structures in MR images of living subjects. Four fresh cadaveric lumbar spines were studied after the injection of coloured gelatin mixed with gadolinium. The specimens were injected by an intraosseous technique. Axial and sagittal fat-saturated T1-weighted MR images were performed on the specimens. Thereafter, specimens were frozen and cut into 5-mm thick slices, three in the axial plane and one in the sagittal plane. All the components of the internal and external venous plexuses were identified on the MR images in correlation with the corresponding anatomic sections. The MR anatomy of the venous system of the lumbar spine is important as it has been implicated in many pathophysiological mechanisms and as it may also cause pitfalls in MR imaging.

A trans STT, trans capitate perilunate dislocation of the carpus. A case report

We report a case of carpal injury not previously described, associating three lesions of the carpus secondary to a hyperextension mechanism: fracture of the capitate, scapho-trapezio-trapezoid sprain and lunotriquetral ligament rupture. The patient was operated by percutaneous pinning after closed reduction. The capitate fracture was not fixed. At follow-up, the patient had no restriction of his everyday activities and was very satisfied.

Thoracic outlet: anatomic correlation with MR imaging

OBJECTIVE

The purpose of this report is to describe the normal MR anatomy of the thoracic outlet and its modification after postural maneuvers using an anatomic-MR imaging correlation.

CONCLUSION

MR imaging appears to be a useful technique to study the thoracic outlet and its contents because of its excellent soft-tissue depiction and its multiplanar capabilities. T1-weighted images obtained in the sagittal plane clearly depicted the different compartments of the cervicothoracic-brachial junction. Hyperabduction maneuvers may have potential applications in the assessment of the thoracic outlet syndrome by showing the location of compression.

[Lumbar lateral recess and intervertebral foramen. Radio-anatomical study]

The recent developments in Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) allow an accurate analysis of the anatomical structures of the lateral recess and of the neural foramen (vertebral body, pedicle, zygapophyseal joints, ligamentum flavum, intervertebral disk) and their contents (spinal ganglion, nerves roots, foraminal veins, surrounding fat). The aim of this study is 1) to describe the normal anatomy and variants of the lateral recess and of the lumbar neural foramen, and 2) to present the main diseases involving this anatomical area.

[The lumbar epidural space. Radio-anatomical study]

The epidural space which extends along the spine, surrounds the dural sac and is bounded by the bony and ligamentous structures of the vertebral canal. The knowledge of the anatomy of this region is important because the high frequency of the pathological processes in this area (tumoral, infections, vascular). The purpose of this presentation is to present the normal radio-anatomy of the lumbar epidural space and then the main pathological processes of this region.

MR imaging of the knee at 0.2 and 1.5 T: correlation with surgery

OBJECTIVE

The purpose of this study was to compare the diagnostic efficacy of low- and high-field-strength MR imagers in the diagnosis of anterior cruciate ligament tears and meniscus tears.

SUBJECTS AND METHODS

In 219 patients with suspected internal derangement of the knee, MR imaging at 0.2 and 1.5 T was performed with similar sequences. Only patients with surgically confirmed diagnosis (n = 90) were included in the statistical analysis. Radiologists were unaware of diagnosis and field strength. Sensitivity, specificity, diagnostic accuracy, and inter- and intraobserver variability were determined.

RESULTS

There was excellent correlation between the field strengths in accuracy, sensitivity, and specificity for anterior cruciate ligament and meniscus tears. Accuracy for medial meniscus, lateral meniscus, and anterior cruciate ligament tears was 91-93%, 88-90%, and 93-96%, respectively, at 0.2 T and 91-94%, 91-93%, and 97-98%, respectively, at 1.5 T. Inter- and intraobserver variability values showed excellent correlation (kappa > 0.8).

CONCLUSION

The level of diagnostic accuracy in anterior cruciate ligament tears and meniscus tears is comparable for low- and high-field-strength MR imagers.

[Imaging of synovial lesions, neoplastic or non-neoplastic]

The purpose of this paper is to present the contribution of imaging in the assessment of synovial diseases, especially in the differentiation between infectious synovitis and rheumatoid arthritis, and in the diagnosis of tumoral and pseudotumoral synovial lesions (idiopathic (osteo)chondromatosis, pigmented villonodular synovitis, synovial hemangioma, lipoma arborescens...).