Maura Valle

Ultrasound of tendons and nerves

Tendons and nerves represent probably one of the best application of musculoskeletal US due to the high lesion detection rate and accuracy of US combined with its low cost, wide availability, and ease of use. The refinement of high-frequency broadband linear-array transducers, and sensitive color and power Doppler technology, have improved the ability of US to detect fine textural abnormalities of these structures as well as to identify a variety of pathological conditions. Characteristic echotextural patterns, closely resembling the histological ones, are typically depicted in these structures using high US frequencies. In tendon imaging, US can assess dislocations, degenerative changes and tendon tears, including intrasubstance tears, longitudinal splits, partial and complete rupture, inflammatory conditions and tendon tumors, as well as postoperative findings. In nerve imaging, US can support clinical and electrophysiological testing for detection of compressing lesions caused by nerve entrapment in a variety of osteofibrous tunnels of the limbs and extremities. Congenital anomalies, nerve tears, and neurogenic tumors can also be diagnosed. Overall, US is an effective technique for imaging tendons and nerves. In most cases, a focused US examination can be performed more rapidly and efficiently than MR imaging.

Power Doppler sonography: clinical applications

OBJECTIVE Color Doppler imaging (CD) has had a great impact on ultrasonography (US). This technique depicts local flow by encoding an estimate of the mean Doppler frequency shift at a particular position in color. However, the choice of the mean frequency shift as the parameter for representing flow in color Doppler is somewhat arbitrary. Power Doppler ultrasound is a technique that encodes the power in the Doppler signal in color. This parameter is fundamentally different from the mean frequency shift. The frequency is determined by the velocity of the red blood cells, while the power depends on the amount of blood present. Providing an image of a different property of blood flow, power Doppler has shown several key advantages over colour Doppler, including higher sensitivity to flow, better edge definition and depiction of continuity of flow. In this paper we review the results of power Doppler clinical studies. MATERIALS AND METHODS All relevant information available in the literature on the potential clinical applications of this technique was revised to give a detailed survey. RESULTS The increased flow sensitivity and better vascular detailing of power Doppler have been used to detect flow presence and characteristics in vessels that are poorly imaged with conventional color Doppler. The improved depiction of tissue vasculature has shown potential advantages, especially in some areas, such as the cortex of native kidneys and renal allografts, the prepuberal testis, the infant hip and the bowel wall, in which color Doppler is not sensitive enough to detect clinically important, slow and poor flow in small vessels. In inflammatory conditions, power Doppler was valuable in depicting increased flow in vessels that are dilated because of inflammatory response. In this field, advantages have been reported in acute cholecystitis and in inflammatory states of musculoskeletal tissues. The higher sensitivity to slow flow and the improved detailing of the course of tortuous and irregular vessels made power Doppler a promising technique to image intratumoral vessels and, thereby, to ameliorate the accuracy of color Doppler in predicting the likelihood of benign versus malignant nature of nodules. Specific flow patterns, missed at color Doppler studies, have been indicated with power Doppler in some tumors of the liver and breast. In different settings, power Doppler also permitted to monitor serial blood flow changes after therapy and to display them as color intensity, allowing the observer to distinguish flow changes. CONCLUSION Although the actual role of power Doppler in changing patient management has not been assessed yet, this technique can depict flow which was previously undetectable, and thus permits an easier and more confident diagnosis in body regions where the ultrasound signal is weak because blood vessels are small.

Development and preliminary validation of a paediatric-targeted MRI scoring system for the assessment of disease activity and damage in juvenile idiopathic arthritis

Objectives To develop and validate a paediatric-targeted MRI scoring system for the assessment of disease activity and damage in juvenile idiopathic arthritis (JIA). To compare the paediatric MRI score with the adult-designed. Outcome Measures in Rheumatology Clinical Trials—Rheumatoid Arthritis MRI Score (RAMRIS), whose suitability for assessing growing joints was tested. Methods In 66 patients with JIA the clinically more affected wrist was studied. Thirty-nine patients had a 1-year MRI follow-up. Two readers independently assigned the paediatric score and the RAMRIS to all studies. Validation procedures included analysis of reliability, construct validity and responsiveness to change. A reduced version of the bone erosion score was also developed and tested. Results The paediatric score showed an excellent reproducibility (interclass correlation coefficient >0.9). The interobserver agreement of RAMRIS was moderate for bone erosions and excellent for bone marrow oedema (BMO). The paediatric score and RAMRIS provided similar results for construct validity. The responsiveness to change of the paediatric score was moderate for synovitis and bone erosion, and poor for BMO and did not improve when RAMRIS was applied. The reduced version of the bone erosion was valuable for the assessment of joint damage, and provided time-saving advantages. Conclusion The results demonstrate that the paediatric MRI score is a reliable and valid method for assessing disease activity and damage in JIA. Unexpectedly, the RAMRIS provides acceptable suitability for use in the paediatric age group. Further work, especially in a longitudinal setting, is required before defining the most suitable MRI scale for assessing growing joints.

Poland syndrome with bilateral features: Case description with review of the literature†

Poland syndrome (PS) has been described as unilateral pectoral muscle deficiency variably associated with ipsilateral thoracic and upper limb anomalies. Bilateral hypoplasia/aplasia of the pectoralis muscle and upper limb defects in association with variable thoracic muscles, chest wall deformities and lower limb defects have been infrequently reported in the literature. We report on a 3½‐year‐old girl with clinical features consisting in bilateral asymmetric pectoral muscle defects (complete agenesis on the left side and agenesis of the sternocostal head on the right side), nipple hypoplasia, left rib defect, and right hand symbrachydactyly. In this study, we reviewed the bilateral features present in our patient and those described in the literature. Hypotheses explaining bilateral features in PS are reviewed.

Skin and Subcutaneous Tissue

From the histologic point of view, the skin varies in thickness from 1.5 to 4.0 mm and is composed of a superficial layer and a deep layer — the epidermis and the dermis, respectively (Fig. 2.1a). The epidermis is made of stratified epithelium, and can be divided into two main layers: the superficial stratum corneum, which is made of closely packed flattened dead cells, and the deep germinative zone (consisting of the stratum basale, stratum spinosum and stratum granulosum). In regions that are not subject to pressure, the epidermis is thin and hairy, whereas in areas undergoing attrition and local shocks (i.e., palms of the hands and soles of the feet), the skin is hairless and may thicken to an even greater extent as a result of a hypertrophied stratum corneum. Deep to the epidermis, the dermis is a thick layer containing large amounts of collagen and a rich network of vessels, lymphatics and nerve endings. It can be divided into a deep reticular layer, which is composed of bulky connective tissue, and a superficial papillary layer, which interdigitates with the base of the epidermis and provides an important mechanical and metabolic support to the overlying epidermis.

Dextrocardia in patients with Poland syndrome: Phenotypic characterization provides insight into the pathogenesis

OBJECTIVE Poland syndrome is a rare congenital anomaly characterized by complete or partial agenesis of the pectoralis major muscle variably associated with other thoracic malformations, upper limb malformations, or both. More than 20 patients with dextrocardia and left-sided Poland syndrome have been previously described. The association between these 2 rare anomalies suggests a causal relationship, but the etiopathogenetic mechanism has not been clarified yet. We studied the clinical correlation between these 2 anomalies, and we tried to elucidate whether dextrocardia or Poland syndrome comes first. METHODS This is a multicentric multidisciplinary study conducted over the last 5 years. We identified 122 patients with Poland syndrome, and we investigated heart position through different imaging techniques. Logistic regression statistical analyses were carried out. RESULTS We observed dextrocardia in 14 (11.5%) patients, which was never associated with situs inversus. All of them presented with left-sided Poland syndrome and partial agenesis of 2 or more ribs. Conversely, all patients with Poland syndrome with partial agenesis of 2 or more ribs presented with dextrocardia, whereas dextrocardia was never associated with partial agenesis of a single rib. Three patients with dextrocardia presented with simple congenital heart defects. CONCLUSIONS These findings suggest that mechanical factors during embryonic life could explain the strong association between left-sided Poland syndrome and dextrocardia. According to this hypothesis, partial agenesis of 2 or more ribs is needed to displace the heart toward the right side. The peculiar features of dextrocardia when associated with Poland syndrome (neither associated with situs inversus nor complex intracardiac anomalies) support our hypothesis.

Paediatric musculoskeletal US beyond the hip joint

US is a technique particularly suited to the investigation of musculoskeletal disorders in children and adolescents. This review paper describes a range of clinical settings beyond the hip joint where US has a significant role to play, including sports injuries, infectious diseases, inflammatory and degenerative conditions, congenital and developmental disorders, acute trauma of bone and joints, and peripheral nerve injuries. In some circumstances, US can be regarded as the most effective means of diagnostic imaging, whereas in other instances, it is an alternative or supplement to other more comprehensive imaging modalities, like MRI and CT. Although MRI offers superior soft-tissue contrast resolution, US is low-cost, non-invasive and has higher spatial resolution and real-time capability for the assessment of musculoskeletal structures during joint movement and stress manoeuvres.

Bone and Joint

All bones consist of peripheral cortical (compact) bone and central medullary (trabecular or cancellous) bone. In long bones, there is an inverse relationship between the amount of cortical and cancellous bone at any given site: in the diaphysis, the cortical bone is thick whereas the trabecular bone is sparse; conversely, metaphyseal and epiphyseal regions are characterized by thin cortical bone and prominent cancellous bone. In addition to bone trabeculae, the medullary cavity contains bone marrow, including yellow marrow (housing fat and connective tissue) and red marrow (consisting of hematopoietic cells, fat and connective tissue). The distribution of hematopoietic and fatty marrow is dependent on age and metabolic state (Ricci et al. 1990). The outer surface of cortical bone is invested by the periosteum—a dense fibrous connective tissue layer that is anchored to the cortical bone by means of perforating Sharpey fibers-which plays a role in allowing rapid healing of fractures.

Development and Initial Validation of a Radiographic Scoring System for the Hip in Juvenile Idiopathic Arthritis

Objective. To develop and validate a radiographic scoring system for the assessment of radiographic damage in the hip joint in patients with juvenile idiopathic arthritis (JIA). Methods. The Childhood Arthritis Radiographic Score of the Hip (CARSH) assesses and scores these radiographic abnormalities: joint space narrowing (JSN), erosion, growth abnormalities, subchondral cysts, malalignment, sclerosis of the acetabulum, and avascular necrosis of the femoral head. Score validation was accomplished by evaluating reliability and correlational, construct, and predictive validity in 148 JIA patients with hip disease who had a total of 381 hip radiographs available for study. Results. JSN was the most frequently observed radiographic abnormality, followed by erosion and sclerosis of the acetabulum. The least common abnormalities were avascular necrosis, growth abnormalities, and malalignment. Interobserver and intraobserver reliability on baseline and longitudinal score values and on score changes was good, with intraclass correlation coefficients ranging from 0.76 to 0.98. Early score changes, but not absolute baseline score values, were moderately correlated (rs > 0.4) with clinical indicators of disease damage at last followup observation, thereby demonstrating that the CARSH has good construct and predictive validity. The amount of structural damage in the hip radiograph at last followup observation was predicted better by baseline to 1-year score change (rs = 0.66; p < 0.0001) than by absolute baseline score values (rs = 0.40; p = 0.002). Conclusion. Our results show that the CARSH is reliable and valid for the assessment of radiographic hip damage and its progression in patients with JIA.

Nerve and Blood Vessels

From the histologic point of view, nerves are round or flattened cords, with a complex internal structure made of myelinated and unmyelinated nerve fibers, containing axons and Schwann cells grouped in fascicles (Fig. 4.1a) (Erickson 1997). Along the course of the nerve, fibers can traverse from one fascicle to another and fascicles can split and merge. Based on the fascicular arrangement, two theories have been hypothesized to explain the internal architecture of a nerve: the “cable” and the “plexiform” models (Stewart 2003). The first states that nerves are cable-like structures, in which fascicles run separately throughout the entire nerve length (Fig. 4.1b). The second asserts that fascicles alternate splitting, branching, and rejoining along the course of the nerve trunk (Fig. 4.1c). In fact, nerves have both cable and plexiform arrangement of the fascicles depending on the level of examination. In their more proximal portion (e.g., brachial plexus), a plexiform organization of the fascicles predominates.