Safety and image quality of MR-conditional external fixators for 1.5 Tesla extremity MR.

PURPOSE: To evaluate the safety and image quality of extremity MR examinations performed with two MR conditional external fixators located in the MR bore. MATERIALS AND METHODS: Single-center retrospective study of a prospectively maintained imaging dataset that evaluated MR examinations of extremities in patients managed with external fixations instrumentation and imaged on a single 1.5T MR scanner. The fixation device was one of two MR-conditional instrumentation systems: DuPuy Synthes (aluminum, stainless steel, carbonium and Kevlar) or Dolphix temporary fixation system (PEEK-CA30). Safety events were recorded by the performing MR radiologic technologist. A study musculoskeletal radiologist assessed all sequences to evaluate for image quality, signal- and contrast-to-noise ratios (SNR/CNR), and injury patterns/findings. RESULTS: In the 13 men and 9 women with a mean age of 42 years (range 18 to 72 years), most patients (19/22 patients; 86%) were involved with trauma resulting in extremity injury requiring external fixation. MR examinations included 19 knee, 2 ankle, and 1 elbow examinations. There were no adverse safety events, heating that caused patient discomfort, fixation dislodgement/perturbment, or early termination of MR examinations. All examinations were of diagnostic quality. Fat-suppressed proton density sequences had significantly higher SNR and CNR compared to STIR (p = 0.01 to 0.04). The lower SNR of STIR and increased quality of fat-suppressed proton density during the study period led to the STIR sequence being dropped in standard MR protocol. CONCLUSION: MR of the extremity using the two study MR conditional external fixators within the MR bore is safe and feasible.

Magnetic Resonance Imaging of the Knee in the Presence of Bridging External Fixation: A Comparative Experimental Evaluation of Four External Fixators, Including Dolphix®.

Performing MR investigation on patients instrumented with external fixators is still controversial. The aim of this study is to evaluate the quality of MR imaging of the knee structures in the presence of bridging external fixators. Different cadaveric lower limbs were instrumented with the MR-conditional external fixators Hofmann III (Stryker, Kalamazoo, MI, USA), Large external Fixator (DePuy Synthes, Raynham, MA, USA), XtraFix (Zymmer, Warsaw, IN, USA) and a newer implant of Ketron Peek CA30 and ERGAL 7075 pins, Dolphix®, (Citieffe, Bologna, Italy). The specimens were MR scanned before and after the instrumentation. The images were subjectively judged by a pool of blinded radiologists and then quantitatively evaluated calculating signal intensity, signal to noise and contrast to noise in the five regions of interest. The area of distortion due to the presence of metallic pins was calculated. All the images were considered equally useful for diagnosis with no differences between devices (p > 0.05). Only few differences in the quantification of images have been detected between groups while the presence of metallic components was the main limit of the procedure. The mean length of the radius of the area of distortion of the pins were 53.17 ± 8.19 mm, 45.07 ± 4.33 mm, 17 ± 5.4 mm and 37.12 ± 10.17 mm per pins provided by Zimmer, Synthes, Citieffe and Stryker, respectively (p = 0.041). The implant of Ketron Peek CA30 and ERGAL 7075 pins showed the smallest distortion area.

Optimal configuration for stability and magnetic resonance imaging quality in temporary external fixation of tibial plateau fractures.

INTRODUCTION: Temporary external fixation has been widely utilized in the stabilization of plateau fractures while waiting for an optimization of the soft tissue conditions before subsequent permanent internal fixation. Simultaneously, MRI is beneficial in the assessment of concomitant damage to ligaments and menisci so that these injuries could be promptly identified, and surgical planning executed at the time of definitive fixation of the bony injury. Increasing numbers of side-bars and pins have been previously suggested to increase frame rigidity, but at the same time, several studies have indicated the presence of MRI artifacts which may obscure key anatomical structures, even when MRI-compatible fixation devices are used. This study aims to identify, among six potential configurations, the construct that maximizes stability while most minimizing the number of MRI artifacts generated among different configurations commonly used. HYPOTHESIS: There is one or more configurations among the others that maximize stability while preserving a clinically acceptable level of MRI quality. MATERIAL AND METHODS: Six constructs were recreated on cadaveric specimens and identified by the disposition of the bars: H, Anterior, Flash, Hashtag, Rhomboid, and Diamond. Stage one evaluated the amount of artifact produced during MRI on instrumented cadaveric legs, as well as the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) at five specific regions of interest. Stage two assessed the amount of compressional and torsional stiffness of the configurations on bone surrogate models. RESULTS: Image artifacts were not detected within the knee joint for all considered constructs. In terms of SNR The H, Anterior, Hashtag, and Diamond configurations were not significantly different from their control (p>0.366) while the others were significantly different (p<0.03). The values of CNR found for the H and Hashtag configurations were not significantly different from their controls (p>0.07) while the remaining configurations were significantly different (p<0.03). In compression, the H and Diamond configurations had similar stiffness (p=0.468) of 35.78N/mm and 31.44N/mm, respectively, and were stiffer than the other configurations. In torsion, the constructs have shown different stiffness (p<0.001) with a minimum value of 0.66 Nm/deg for the Rhomboid configuration, which was significantly less stiff than the Anterior configuration (1.20 Nm/deg [p<0.001]). There was no difference between the Diamond and H configurations (p=0.177) or between them and the Hashtag configuration (p=0.215). DISCUSSION: An external fixator construct directly bridging the femur and tibia without interconnections is the most stable and produces MRI scans without image artifacts that would interfere with diagnostic quality. LEVEL OF EVIDENCE: V, basic science study, diagnostic imaging and mechanical testing.

Correction to: Ultrasound localization of lacerated flexor tendon ends in the hand: a cadaveric study.

In the results section of the abstract, it states "99.0% (n = 05/96 tendons)" when it should state "99.0% (n = 95/96 tendons)".

Ultrasound localization of lacerated flexor tendon ends in the hand: a cadaveric study.

OBJECTIVE: Flexor tendon repair currently requires extensive exposure to locate and repair tendons. Ultrasound (US) has been used to identify lacerated tendon ends with little information on accuracy. This study was designed to measure the accuracy of US to localize tendon ends in zone II flexor tendon lacerations in a cadaveric model. MATERIALS AND METHODS: US was used to locate tendon ends in zone II lacerations of fingers of six cadaveric hands (96 tendon ends) by a musculoskeletal radiologist. The distance of each tendon end relative to the laceration was recorded. Specimens were dissected and tendon position was compared to US position. RESULTS: The radiologist correctly identified full-thickness lacerations of both superficial and deep tendons 99.0% (n = 05/96 tendons) of the time. The average difference between mean US predicted retraction and anatomic confirmed retraction for all digits all tendons was 3.5 mm of underestimation. US correctly identified the position of all tendon stumps to within 10 mm 92.7% (n = 89/96 tendons) of the time and 69.8% (n = 67/96 tendons) of the time to within 5 mm. Error tended to underestimate (61.5%; 59/96 tendons) rather than overestimate retraction (29.2%; 28/96 tendons). CONCLUSIONS: This fresh cadaveric study has demonstrated that with an experienced radiologist, there was 99.0% accuracy identifying a completed tendon tear and locating the tendon ends with US to within 1 cm was 92.7% accurate.

Auto-obliteration of maxillary sinuses through osteoneogenesis in children with cystic fibrosis: A possible new way to reduce morbidity.

BACKGROUND: Cystic Fibrosis is an autosomal recessive disorder with a mutation in the cystic fibrosis transmembrane regulator gene, leading to dysregulation of epithelial fluid transport, dehydration of airway surfaces and impaired mucociliary function in the sinuses, lungs, pancreas and other organs. This leads to thickened secretion which blocks the sinus ostia and promotes chronic bacterial overgrowth and destruction of the mucosa. Chronic rhinosinusitis in cystic fibrosis patients leads to a decreased quality of life involving increased hospitalizations, infections, pneumonia, and acute exacerbations, warranting multiple sinus surgeries. This study investigates the effects of a more aggressive surgical approach on reducing the need for repeat surgeries. METHODS: A retrospective review of CT scans of nine cystic fibrosis patients who have had aggressive endoscopic sinus surgery for the treatment of chronic rhinosinusitis (CRS) was performed. The decrease in maxillary sinus volume was measured using pre-operative and post-operative scans. RESULTS: A significant decrease in maxillary sinus volume was observed in all subjects. Volume reduction occurred through osteoneogenesis, causing auto-obliteration of the sinuses with cancellous bone. CONCLUSIONS: Aggressive endoscopic sinus surgery for maxillary sinuses incites an osteoneogenetic reaction that leads to auto-obliteration of the sinus and reduces sinus-related morbidity in children with cystic fibrosis. Through this osteoneogenesis, the sinus is transformed into a shallow cup that does not retain secretions and is easy to clear. It is our impression that this may lead to reduced morbidity and a decreased need for repeat maxillary sinus surgery.

Multimodality imaging findings in rhabdomyolysis and a brief review of differential diagnoses.

Rhabdomyolysis has traditionally been a clinical diagnosis with healthcare providers utilizing historical context, physical exam, and laboratory data to arrive at a diagnosis. However, there are myriad imaging findings that may be corroborative and support the presumptive diagnosis. This paper seeks to review imaging findings associated with rhabdomyolysis using different modalities including radiography, sonography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy.

The Non-Innoculous Hilar Calcification: Recurrent Pneumonia Secondary to Broncholith-Associated Actinomyces.

Dystrophic calcification of hilar lymph nodes is a common response to chronic inflammation related to several etiologies and rarely is associated with any clinical findings. A clinical scenario related to these calcified lymph nodes can thus be delayed by the low clinical suspicion associated with such a presumably innocuous finding. Normal respiratory movements however, can cause erosion into adjacent bronchi leading to a broncholith, complications of which can result in morbidity. We illustrate one of these complications, a partial obstruction with subsequent recurrent infection due to normal oral flora - actinomyces.

Tendon entrapments and dislocations in ankle and hindfoot fractures: evaluation with multidetector computed tomography.

The purpose of this study was to assess the incidence of tendon entrapments and tendon dislocations associated with ankle and hindfoot fractures in patients studied by multidetector computed tomography (MDCT). Additionally, we describe particular tendon injuries associated with specific fractures. This was a retrospective review of all individuals with a trauma-protocol CT for suspected ankle and/or hindfoot fractures during a consecutive 41-month time period at a single Level I Trauma Center. Each patient's images were evaluated by two radiologists and an orthopedic surgeon for tendon entrapment, tendon dislocation, and bone(s) fractured or dislocated. There were 398 patients with ankle and/or hindfoot fractures that showed tendon entrapment or dislocation in 64 (16.1 %) patients. There were 30 (46.9 %) patients with 40 tendon entrapments, 31 (48.4 %) patients with 59 tendon dislocations, and three (4.7 %) patients with both tendon entrapment and dislocation. All patients with tendon entrapments were seen with either pilon fractures and/or a combination of posterior, medial, or lateral malleolar fractures. The most frequently entrapped tendon was the posterior tibialis tendon (PTT) in 27 patients (27/30, 90.0 %). The peroneal tendons were the most frequently dislocated, representing 27 (87.1 %) of patients with tendon dislocation; all resulted from a talar or calcaneal fracture or subluxation. This study demonstrates that tendon entrapments and tendon dislocations are commonly seen in complex fractures of the ankle and hindfoot. Pilon fractures were associated with the majority of tendon entrapments, whereas calcaneus fractures were associated with the majority of tendon dislocations.

Celiacomesenteric trunk: a rare anatomical variation with potential clinical and surgical implications.

The arterial supply of the abdominal viscera is derived via three single arteries: the celiac axis, the superior mesenteric artery, and the inferior mesenteric artery. These arteries usually originate separately from the ventral aspect of the abdominal aorta. In some cases, two or more of these arteries may originate from a common trunk. The celiacomesenteric trunk is a rare condition that can generate clinical and surgical complications. Preoperative knowledge of vascular anomalies is critical when planning a surgical approach. We report a patient who underwent Multi-detector Computed Tomography (MDCT) before a vascular procedure, and a common trunk for celiac axis and superior mesenteric artery (celiac mesenteric trunk) was incidentally found.

A clearly observable cold fracture line of an early occult hip fracture on bone scintigraphy.

Although a true fracture is commonly associated with increased radionuclide uptake on bone scintigraphy, it is also possible for an area with no increased uptake (a cold line) to indicate fracture, as demonstrated in this case study. Detection of an occult acute hip fracture through recognition of a cold fracture line is important because of the associated therapeutic, economic, and medicolegal implications.

Anemia de células falciformes: hallazgos radiológicos de las complicaciones en el tórax / Sickle Cell Anemia: Imaging Findings of Thoracic Complications

La anemia de células falciformes es una enfermedad autosómica recesiva que se caracteriza por hematíes rígidos que no pueden atravesar normalmente los capilares de los tejidos, y son destruidos y eliminados de la circulación. La escasa deformidad que tienen los glóbulos rojos falciformes facilita la formación de trombos y ocasiona oclusión vascular. Las complicaciones secundarias a la trombosis vascular son las que causan mayor impacto clínico. En este artículo revisamos las manifestaciones radiológicas de las complicaciones en el tórax de esta enfermedad.

Sickle cell anemia is an autosomal recessive disease characterized by rigid Red Blood cells (RBCs) that cannot pass through the capillaries of the tissue, and are destroyed and removed from circulation. The low deformity of the RBCs eases thrombus formation and vascular occlusion. Complications secondary to vascular thrombosis have the greatest clinical impact. In this paper, we review the radiologic manifestations of chest complications which result from this disease.

Anatomic guide and sonography for surgical repair of leg muscle lacerations.

BACKGROUND: There were over 110,000 leg laceration cases reported in the United States in 2011. Currently, muscle laceration is repaired by suturing epimysium to epimysium. Tendon-to-tendon repair is stronger, restores the muscle's resting length, and leads to a better functional recovery. Tendons retract into the muscle belly following laceration and surgeons have a difficult time finding them. Many surgeons are unfamiliar with leg muscle anatomy and the fact that the leg muscles have long intramuscular tendons that are not visible in situ. A surgical anatomic guide exists to help surgeons locate forearm tendons; no such guide exists for tendons in the leg. MATERIALS AND METHODS: The leg tendon ends of 11 cadavers were dissected, measured, and recorded as percentages of leg length. High-frequency ultrasound was used to locate tendon ends in three additional cadavers. These locations were compared with the actual tendon ends located via dissection. RESULTS: There was little variation in tendon end position within the cadaver group, between men and women or right and left legs. The data are presented as an anatomic guide to inform surgeons of the tendon ends' likely locations in the leg. CONCLUSION: The location of leg intramuscular tendon ends is predictable and the anatomic guide will help surgeons locate tendon ends and perform tendon-to-tendon repairs. Ultrasound is a potentially effective tool for detection of accurate location of repairable tendon ends in leg muscle lacerations.

High frequency ultrasound evaluation of traumatic peripheral nerve injuries.

OBJECTIVE: Accurate diagnosis and localization of peripheral nerve traumatic injury remains difficult. Early diagnosis and repair of nerve discontinuity lesions lead to better outcome than delayed repair. MATERIALS AND METHODS: We used new high frequency ultrasound to evaluate 24 patients with 29 traumatic nerve injuries. There were a variety of causes including gunshot wounds, blunt injuries, burns, stabbings, and motor vehicle accidents. The patients were then either treated surgically with nerve status directly observed or followed clinically for recovery of nerve function. RESULTS: The ultrasound findings correspond with the clinical outcome of 28 of the 29 nerves. CONCLUSION: While this is a study limited by a small patient number, ultrasound evaluation should be considered in the evaluation of nerve injury and can lead to early diagnosis and treatment of surgical nerve injuries.

Parosteal lipoma of the rib: a benign condition that mimics malignancy.

Parosteal lipomas (PL) account for 0.3% of all lipomas. They are composed of adipose tissue adjacent to the bone cortex and elicit bony reactive changes. Location of this typically slow-growing indolent lesion in the ribs is unusual. Albeit a benign condition, PL imaging findings may be misinterpreted as a malignant lesion. We present a patient with a PL in which a surgical biopsy was performed. Distinctive features of PL in the computed tomographic (CT) scan and magnetic resonance image (MRI) are described. Familiarity with the characteristic radiographic PL signs assist in avoiding invasive diagnostic studies. Lipomas are benign tumors consisting of mature fat cells. They are the most common mesenchymal neoplasias and account for 50% of all soft tissue tumors. Their location varies from superficial to deep seated lesions. Musculoskeletal lipomatous lesions may be located in bones, soft tissues, and may also affect joint and tendon sheaths. PL is a rare benign deep fatty-tissue tumor that arises contiguous to the periosteum without originating from it. In 1836, Seering was the first in describing this lesion and named it "periosteal lipoma." Upon realization that there are no adipocytes in the periosteum, the term was changed to the more descriptive "parosteal lipoma" by Power in 1888. This is a case report of a patient with a chest wall mass that on CT scan and MRI had the typical PL appearance. This pattern allows one to identify the lesion and thus, to differentiate it from malignant conditions.

Evaluación mediante resonancia magnética (RM) de las lesiones obstétricas del plexo braquial / Obstetrical brachial plexus injuries: a MRI diagnostic approach

Propósito. Demostrar la utilidad de la resonancia magnética (RM) en la evaluación de las lesiones obstétricas del plexo braquial. Material y métodos. Fueron evaluados mediante RM de campo alto (1,5 Tesla) 23 pacientes con semiología correspondiente a parálisis del plexo braquial. Se estudió con bobina de cerebro en los planos axial, coronal oblicuo y sagital en secuencias ponderadas para T1, T2 y STIR. Resultados. En cuatro pacientes (17 por ciento) el examen fue considerado como normal. En 19 pacientes (83 por ciento) se obtuvieron hallazgos patológicos (pseudomeningoceles, neuromas, tumor y quiste aracnoideo). Conclusión. La RM es un método no invasivo que logra determinar el sitio y grado de compromiso del plexo braquial, permitiendo de esta manera programar en forma precisa la terapéutica a instituir (AU)

Lesión de SLAP: evaluación mediante RM dinámica y artrorm dinámica / Superior labrum anteroposterior (SLAP) lesion: evaluation with dynamic MRI and MR-arthrography

Propósito: presentar nuestra experiencia en pacientes con inestabilidad articular de hombro y RM convencional no concluyente, evaluando los signos de lesión de SLAP en RM dinámica (RMD) y ArtroRM dinámica (ARMD). Material y método: se realizó un estudio prospectivo evaluando mediante RMD y ARMD a 10 pacientes con inestabilidad articular y RM convencional previa no concluyente. Se analizaron los signos positivos para lesiones del complejo bicípito labral (CBL), las lesiones asociadas del manguito rotador y complejo labro ligamentario; y los falsos positivos y negativos. Evaluamos las variantes de la lesión acorde a la clasificación artroscópica de Snyder (tipo I herida labral pura, tipo II avulsión del CBL, tipo III herida en asa de balde que respeta al tendón bicipital y tipo IV herida en asa de balde que se extiende dentro del tendón bicipital), aceptada en forma unánime en la práctica traumatológica nacional e internacional. Resultados: se descubrieron 8 casos con signos positivos para lesiones de tipo SLAP, 6 ARMD y 2 RMD. En 2/10 casos no se observaron lesiones SLAP. La totalidad presentaba alguna otra lesión tendinosa, labral u osteocartilaginosa asociada y diagnosticada previamente en la RM convencional. Conclusión: la RMD y la ARMD han demostrado ser de utilidad en la presentación de la lesión de SLAP y su clasificación, contribuyendo al diagnóstico completo y planeamiento quirúrgico apropiado (AU)