MRI identification of pseudolesions in the distal tibia articular surface: Frequency and diagnostic criteria

OBJECTIVE

Pseudolesions of joints are known as focal irregularities of chondral or subchondral bone in typical joint areas and occur frequent but without clinical relevance. This study aims to report the prevalence and describe MRI findings of a previously unreported chondral, mostly posterior located pseudolesion of the distal tibia, and to define criteria to distinguish it from pathologic osteochondral lesions, as well as from another known pseudolesion of this area - the so called "Notch of Harty".

MATERIAL AND METHODS

A tri-centric retrospective case-control study included a total of 2,428 patients with ankle MRI examinations performed over a period of 6 years. MRI scans were evaluated by three radiologists in consensus for any cartilage irregularity of the distal tibial articular surface. For this purpose, the tibial articular surface was divided into 9 topographic regions. Proton-density weighted, fat-suppressed sequences in sagittal and coronal acquisition were used to assess the postero-medial articular surface of the tibia. Imaging features such as size and localization of cartilage irregularity and/or a cortical mould as well as presence of associated edema and/or subchondral cysts were reported. Demographic data (sex, age, and weight) was also recorded. Clinical data comprised presence of pain, movement impairment, and concomitant pathologies.

RESULTS

A total of 68 patients (34 male, 34 female) with a lesion of the distal tibia were identified that had a new pseudolesion (prevalence of 3%). These lesions occurred most frequently (50 out of 68, 74%) in the postero-medial distal tibia plafond and were more commonly detected in the age group of 9-30 years (47%). In 13 of these 68 cases, the cartilage irregularity was the sole lesion without subchondral abnormalities. By defining these cases as definite pseudolesions, the prevalence was 1% and their age distribution was similar to that of the 55 other lesions with subchondral changes. Here with 11 of the 13 cases the majority (85%) were seen in the posterior part, especially in the postero-medial part (55%) of the distal tibia. The size of the cartilage defect ranged from 1 to 7 mm, and the majority (69%) sized from 2 to 3 mm. In 36 of 68 patients, we have seen subchondral alterations such as edema and/or cysts in addition to cartilage irregularity. 66% (n = 45) of these changes were edema and 37% (n = 25) were cysts. None of these 68 new pseudolesions with or without subchondral changes needed surgical or arthroscopic intervention. In the radiological and orthopaedic reports, clinical symptoms such as pain or instability were never associated with our observed lesions and there was no significant correlation between the presence of motion-related pain and imaging findings of cartilage irregularity, subchondral edema, and subchondral cysts. Thirteen patients had MRI follow-up examinations. Here the lesions did not show any MR morphological changes or clinical deterioration. Besides the new pseudolesion, which occured mainly in the posterior part of the tibia surface, we observed the "Notch of Harty" with a higher prevalence (25%) in our patient cohort. The typical localization was in the antero-medial tibial articular surface, without any edema or cysts. There were no coincidences of patients with both a new pseudolesion and the "Notch of Harty" CONCLUSION: A new pseudolesion is typically seen in the postero-central and postero-medial tibial articular surface with a prevalence of 3% and may be associated with only a small cartilage irregularity. In many cases, however, additional findings such as bone edema and/or an adjacent bone cysts were found, which impairs differentiation of these lesions from pathologic osteochondral lesions. The latter are obviously often associated with a larger cartilage defect and clinical symptoms. Due to the balanced age distribution between those pseudolesions with and without subchondral changes and the lack of clinical symptoms, we conclude that the here reported pseudolesions are not a predilection for a clinically manifest osteochondral lesion (OCL). At the very least, the apparent lack of clinical relevance increases the likelihood that we are dealing with a new true pseudolesion.

Fast, High-Fidelity Addressed Single-Qubit Gates Using Efficient Composite Pulse Sequences

We use electronic microwave control methods to implement addressed single-qubit gates with high speed and fidelity, for ^{43}Ca^{+} hyperfine "atomic clock" qubits in a cryogenic (100 K) surface trap. For a single qubit, we benchmark an error of 1.5×10^{-6} per Clifford gate (implemented using 600 ns π/2 pulses). For 2 qubits in the same trap zone (ion separation 5  μm), we use a spatial microwave field gradient, combined with an efficient four-pulse scheme, to implement independent addressed gates. Parallel randomized benchmarking on both qubits yields an average error 3.4×10^{-5} per addressed π/2 gate. The scheme scales theoretically to larger numbers of qubits in a single register.

Robust Quantum Memory in a Trapped-Ion Quantum Network Node

We integrate a long-lived memory qubit into a mixed-species trapped-ion quantum network node. Ion-photon entanglement first generated with a network qubit in ^{88}Sr^{+} is transferred to ^{43}Ca^{+} with 0.977(7) fidelity, and mapped to a robust memory qubit. We then entangle the network qubit with a second photon, without affecting the memory qubit. We perform quantum state tomography to show that the fidelity of ion-photon entanglement decays ∼70 times slower on the memory qubit. Dynamical decoupling further extends the storage duration; we measure an ion-photon entanglement fidelity of 0.81(4) after 10 s.

[Clinical radiological evaluation of teeth-part 2 : Caries, inflammatory dental changes and important differential diagnoses]

Inflammatory diseases of the teeth and periodontium are widespread and are frequent secondary diagnoses in head and neck examinations. Periapical inflammation can be the cause of sinusitis or abscess formation in the oral and maxillofacial region. Early detection is important for the patient's course of treatment. For further diagnostics, a dental presentation should be carried out. Dental radiological examinations, such as panoramic radiographs and dental films are used for specific diagnostics. This article is intended to provide an overview of the different stages of caries, the most important inflammatory dental changes and their most frequent differential diagnoses.

[Clinical radiological evaluation of teeth-part 1 : Anatomy and anomalies]

Radiological assessment of the teeth and periodontium is often left to the dentist. Nevertheless, it is useful to know the anatomy and possible anomalies of the teeth in order to correctly assess pathological processes in both projection radiographic and slice imaging. Dental radiological examinations, such as panoramic slice imaging (PSA) and dental film are used for targeted diagnostics. In the case of incidental findings, a dental presentation should be made for further clarification. This article first provides an overview of the anatomy and anomalies of teeth.

[Imaging of chronic inflammatory bowel diseases in childhood and adolescence : Repetitorium]

Chronic inflammatory bowel diseases can already occur in childhood and in contrast to affected adults, are more frequently manifested as unspecific symptoms. Therefore, at the time of diagnosis the gastrointestinal tract may already be severely affected. Both the diagnostic methods and the treatment concept, which is ideally carried out by pediatric gastroenterologists, differ from those used in adults. The primary diagnostics mainly include sonography and hydro-magnetic resonance imaging (MRI), whereby each modality offers certain advantages depending on the patient and the examiner but is also subject to limitations in terms of feasibility and evaluation. Imaging diagnostics contribute not only to finding the diagnosis but also to assessing the extent of the disease. They also serve to monitor the course of the disease in terms of treatment response or failure, to assess the activity and to detect and quantify possible complications, such as fistulas or abscesses.

[Chronic nonbacterial osteomyelitis : Imaging and differential diagnoses]

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease in childhood and adolescence with a preference for the female gender. It is manifested with multiple osseous lesions, with a predilection for the metaphyseal end zones of the long bones of the lower extremities. These bone lesions usually occur multifocally, can recur and develop a different appearance depending on the bone structure affected. Patients present with a longer disease history, changing clinical symptoms and unspecific paraclinical signs. Magnetic resonance imaging (MRI) is the imaging of choice and particularly as a whole body examination can speed up the diagnosis and is an important component of follow-up controls. Differential diagnoses include numerous inflammatory, benign and malignant bone diseases. Therefore, it is essential to know the diagnosis of CNO and to take it into consideration in cases of an unclear inflammatory bone process in young patients.

[Dental X-ray diagnostics with the orthopantomography - Technique and typical imaging results]

Despite the increasing use of modern digital cross-sectional imaging techniques (especially digital volume tomography) in dental X‑ray examinations, orthopantomography remains the widely available, commonly used basic imaging modality for evaluating dental status prior to extensive treatment. It is also used for inflammatory and tumorous odontogenic osseous pathologies which are demonstrated with typical imaging findings. The classical X‑ray tomography principle has been further developed for the presentation of the differently wide, shape variants of dental arches. The examination unit, consisting of a rigidly connected X‑ray tube and detector, runs on an elliptical path around the facial skull. Thereby different rotation centers are controlled. Due to the different distances of the jaw sections to the X‑ray tube and the image receiver, differencing velocities result and thus blurring effects as the basis of the layer or slice representation. Slit collimators lead to a narrow and continuous line-like representation of the different widths of the dental arch.

[MR and CT arthrography in cartilage imaging : Indications and implementation]

BACKGROUND

The imaging of chondral pathologies is an essential part in the work-up of acute and chronic joint diseases. Besides conventional MR imaging, CT and MR arthrography are well-established methods in evaluating articular cartilage. The application of these techniques requires knowledge of indications and safe injection procedures by the performing radiologist.

PURPOSE

Our goal is to describe the techniques of cross-sectional arthrographies of different joints, give an overview of general and joint-specific considerations for practical application as well as provide typical indications for cartilage imaging.

MATERIALS AND METHODS

A selective PubMed literature search concerning "arthrography", "CT arthrography", "MR arthrography", "arthrography cartilage", "arthrography wrist", "arthrography elbow", "arthrography shoulder", "arthrography hip", "arthrography knee", "arthrography ankle", "arthrography complications", "arthrography imaging guidance" "osteochondral lesion", "cartilage imaging" and "cartilage lesion" was performed.

RESULTS AND CONCLUSION

CT and MR arthrography are valuable and safe tools in cartilage imaging. They are useful to verify and specify chondral pathologies, usually after conventional MR imaging, and have an important role in evaluating the stability and therefore in therapeutic decision making of osteochondral lesions. CT arthrography is not only a substitute technique in case of MR contraindications, it can be advantageous in small joints (wrist, elbow, ankle) compared to MR arthrography due to its higher image resolution. Fluoroscopic guided joint puncture is still the most commonly used image guidance method, but the role of ultrasound is steadily increasing. Joint traction in MR arthrography is a promising technique to improve cartilage visualization, though it is not yet used in clinical routine imaging.

[Osteoarthritis classifications : Modification proposal for the criteria of Kellgren and Vallotton]

BACKGROUND

In imaging diagnostics, classification schemes are very common. As far as osteoarthritis is concerned, the Kellgren classification is the most popular. However, the Kellgren classification, which has been used for more than 50 years, is based on nonspecific criteria; thus, high interobserver variability has been reported. In addition, the Kellgren classifications have not been coordinated with magnetic resonance imaging (MRI)-based classification schemes, e.g., Vallotton.

AIM

In this paper, we present some modifications concerning the criteria for both the Kellgren classification and its comparison with the MRI-based Vallotton classification.

METHODS

The current surgical and imaging classifications and the precision of the nomenclature are analyzed. X‑ray and MRI findings are compared.

RESULTS

Suggestions for both a modification of the Kellgren classification as far as the criteria are concerned and a hierarchy (ranking) of X‑ray and MRI findings to make clinical decisions more valuable are proposed.

CONCLUSION

These proposed modifications (Kellgren and ranking) would be helpful for routine reporting and allow for better interobserver reliability, in particular for special reports (e.g. consultations, expert opinions, advanced diagnostics).

[Ultrasound of the elbow-standard examination technique and normal anatomy]

CLINICAL/METHODICAL ISSUE

Ultrasound of the elbow facilitates easily accessible evaluation of different pathologic conditions. The background for evaluating any pathologic state is the well-grounded knowledge of normal anatomy and standard ultrasound technique.

STANDARD RADIOLOGICAL METHODS/METHODICAL INNOVATIONS/PERFORMANCE

A unique feature of ultrasound compared to other imaging modalities of the elbow is the possibility of dynamic imaging, the examination of the patient at the bedside and the direct assessment of the contralateral side as a reference.

AIM

The aim of this article is to present standard ultrasound technique in examining the elbow. A four-quadrant model of the elbow is used and the recommendations of the DEGUM (German Society of Ultrasound in Medicine) and ESSR (European Society of Musculoskeletal Radiology) are followed.

[Injuries of ligaments and tendons of foot and ankle : What every radiologist should know]

Injuries of the ligaments and tendons of the ankle and foot are among the most common musculoskeletal injuries. A correct and precise description of the pathology and possible accompanying injuries is essential for treatment planning by trauma and orthopedic surgeons. While X‑ray is used to exclude fractures, ultrasound is a very useful tool to assess the ligaments and tendons. For the radiologist, magnetic resonance imaging (MRI) is invaluable regarding the correct assessment of (partial) ruptures, as well as for evaluating accompanying injuries. The aim of the present overview is to provide the most relevant facts for radiologists regarding injuries of ligaments and tendons of the ankle and foot. A description of expected MRI findings and possible pitfalls are presented. For each ligament complex or tendon, we review the anatomy, followed by relevant facts on biomechanics and typical findings in case of injury. The lateral and medial ligament complex, syndesmosis, spring ligament complex, and the Lisfranc ligament are shown in detail. The Achilles tendon and the peroneal tendons are also discussed.

[Neurogenic myopathies and imaging of muscle denervation]

CLINICAL ISSUE

Neurogenic myopathies are primary diseases of the nervous system, which secondarily result in denervation of the target musculature. The spectrum of potential causes is manifold ranging from acute traumatic injuries and chronic compression to neurodegenerative, inflammatory, metabolic and neoplastic processes.

STANDARD DIAGNOSTIC METHODS

The medical history, clinical neurological examination, and electrophysiological tests including electromyography and nerve conduction studies are crucial in diagnosing neuropathic myopathies. Electromyography is the gold standard for diagnosing muscle denervation.

METHODICAL INNOVATIONS

Additional imaging methods and magnetic resonance imaging (MRI) in particular, are capable of contributing valuable information. The MRI examination of denervated musculature shows edema, an increase in the apparent diffusion coefficient (ADC) and hyperperfusion. Chronic denervation results in fatty degeneration and atrophy of affected muscles, which are also detectable by MRI.

PERFORMANCE

Although the MRI findings in muscle denervation are relatively unspecific, they show a high sensitivity, comparable to electromyography. Dedicated MR neurography may often visualize the underlying lesion(s) of the innervating nerve(s).

ACHIEVEMENTS

Besides high sensitivity, comparable to electromyography, MRI is capable of evaluating muscles which are inaccessible for needle electromyography. Due to its non-invasive character, MRI is ideal for follow-up examinations.

PRACTICAL RECOMMENDATIONS

The use of MRI is often a meaningful addition to the diagnostics of neurogenic myopathies. The extent and distribution pattern of muscular alterations often provide information on the localization of the causative nerve damage. A correct diagnosis or at least a narrowing down of possible differential diagnoses can often be achieved using MRI.

[Mazabraud and McCune-Albright syndromes in association : A case of two very rare orthopaedic tumour entities]

We report on a 47-year-old woman with unilateral fibrous dysplasia and three intramuscular masses. Medical imaging revealed possible intramuscular myxomas, so that the suspected diagnosis was Mazabraud syndrome. After biopsy, the suspected diagnosis was verified by histology and molecular pathology. Due to endocrine abnormalities in the patient's medical history, McCune-Albright syndrome has was also verified.

[Certification in cardiology : Contra: The concept should be improved]

Increasing complexity and new highly differentiated therapeutic procedures in cardiology result in a need for additional training beyond cardiology board certification. The German Cardiac Society therefore developed a variety of certifications of educational curricula and definition of specialized centers. Standardization and structuring in education and patient treatment, as defined by certifications may be helpful; however, introduction of certification can have serious consequences for hospital structure, the side effects of which may impair quality of treatment for individual patients. The current article discusses these issues against the background of the following questions: how is quality defined? How do certifications interfere with patient care on a nationwide level, how do they influence responsibilities and teamwork? Are there conflicts of interests by designing certifications and how good are the organizational structures? Finally, suggestions are made on what has to be considered when designing certifications. Certifications should acknowledge all cardiologists, irrespective of their position in the level of care. There should be a coherent unified concept synchronizing all certifications and administration needs to be transparent and well structured.

[Focal lesions in whole-body MRI in multiple myeloma : Quantification of tumor mass and correlation with disease-related parameters and prognosis]

BACKGROUND AND OBJECTIVES

In this study, we evaluated methods of quantification of tumor mass in whole-body MRI (wb-MRI) in multiple myeloma and correlated these with disease-related parameters in serum and bone marrow.

MATERIALS AND METHODS

We retrospectively evaluated wb-MRIs of 52 patients with focal infiltration pattern and a total of 700 focal lesions (subsequently called lesions). We determined the longest diameter (LD), the segmented volume (SV), and the morphology (spherical or non-spherical). We correlated total number/volume of the lesions with clinical parameters and prognosis and furthermore LD with SV. After that we analyzed the agreement of SV and estimated volume (EV) using the volume formula of a sphere based on LD.

RESULTS

Results showed no significant correlations of total number/volume with prognosis or clinical parameters. The latter were situated predominantly in the normal range. Furthermore, 10% of lesions were spherical. SV and LD correlated significantly in single lesions and on patient level. SV was in lesions <6 cm³ systematically larger and in lesions ≥6 cm³ smaller than EV. In 95%, we found in small lesions a deviation of EV versus SV from +0.9 cm³ to -4.6 cm³ and in large lesions from +160 cm³ to -111 cm³ (EV-SV).

CONCLUSIONS

Quantification of tumor mass in the focal infiltration pattern is performed more accurately by volumetry than LD due to the predominant existence of non-spherical lesions. The patient cohort with clinical parameters predominantly in the normal range is distributed to ISS stage I and partly pretreated, a fact that makes interpretation of absent correlations more difficult. Consider also a variation in activitiy of lesions and a diffuse infiltration not detectable by MRI.

CT-Guided Percutaneous Spine Biopsy in Suspected Infection or Malignancy: A Study of 214 Patients

Purpose: To retrospectively determine the effectiveness and accuracy of CT-guided percutaneous biopsy of malignant and inflammatory bone lesions of the spine and to assess the reliability of pre-biopsy CT and MRI. Materials and Methods: 214 patients with lesions of the spine, which were suspicious either for being malignant or inflammatory, underwent CT-guided biopsy for pathological and/or microbiological detection. Biopsy samples were sent for histological examination in 128/214 patients, for microbiological analysis in 17/214 patients and for both analyses in 69/214 patients. Retrospectively, the diagnostic accuracy and sensitivity/specificity of the pre-interventional imaging (CT and MRI) were determined. In addition, the influence of the biopsy on subsequent patient management was assessed. Results: The accuracy was 94.4 % for histopathological analysis and 97.7 % for microbiological analysis. In 25 % of cases the microbiological analysis revealed an underlying pathogen that was not significantly affected by pre-biopsy antibiotic therapy. The sensitivity/specificity of the pre-biopsy cross-sectional imaging concerning suspected malignancy was 69 %/78 %. For suspected infection, the sensitivity/specificity of pre-biopsy imaging was 81 %/44 %. In 52 % of all cases, the biopsy result changed subsequent patient management. Conclusion: Percutaneous CT-guided spine biopsy is a useful and reliable diagnostic procedure to establish a definitive diagnosis but with a relatively low yield of microorganisms in the case of infection. Key Points: • CT-guided spine biopsy is an accurate and reliable procedure in case of infection and tumour.• The results of the CT-guided spine biopsy have a significant influence on the subsequent patient management.• Pathogen recovery-rate in case of infection is moderate but not significantly affected by prebiopsy antibiotic therapy. Citation Format: • Rehm J, Veith S, Akbar M et al. CT-Guided Percutaneous Spine Biopsy in Suspected Infection or Malignancy: A Study of 214 Patients. Fortschr Röntgenstr 2016; 188: 1156 - 1162.

Modern Radiological Imaging of Osteoarthritis of The Hip Joint With Consideration of Predisposing Conditions

Osteoarthritis is the most common disease of the hip joint in adults and has a high socioeconomic impact. This review article discusses the value of three imaging modalities in the diagnosis of osteoarthritis of the hip joint: projection radiography, computed tomography, and magnetic resonance imaging (MRI). Besides established imaging diagnostics of osteoarthritis, this review also outlines new MRI techniques that enable the biochemical analysis of hip joint cartilage and discusses predisposing deformities of the hip joint including femoroacetabular impingement (FAI) with labral pathologies, hip joint dysplasia, malrotation, and, finally, femoral head necrosis, for which early detection and an exact description of the extent and localization of the necrotic area are extremely important. Conventional X-rays remain indispensable for the diagnosis of osteoarthritis, while MRI is able to depict additional early symptoms and signs of activity of the disease. With the increasing number of joint-preserving interventions such as surgical hip luxation and hip joint arthroscopy for treating FAI, high-resolution imaging is gaining further importance for both pre- and postoperative diagnostics because it can accurately recognize early stages of joint damage. With high-resolution MR sequences and MR arthrography, the detailed depiction of the thin cartilaginous coating of the hip joint has become quite possible.

KEY POINTS

• Projection radiography is the method of choice for the diagnostic work-up of osteoarthritis of the hip joint.• Using computed tomography, the amount of acetabular bone stock prior to total hip arthroplasty is assessed in selected patients.• Magnetic resonance imaging can substantiate the indication of surgery in case of discrepancy between clinical symptoms and radiological findings of the hip joint.• If distinct and left untreated, predisposing conditions (such as femoroacetabular impingement) may lead to early development of osteoarthritis of the hip joint.• Functional cartilage imaging can verify changes in the biochemical composition of the cartilage before they become morphologically evident. Citation Format: • Weber MA, Merle C, Rehnitz C et al. Modern Radiological Imaging of Osteoarthritis of The Hip Joint With Consideration of Predisposing Conditions. Fortschr Röntgenstr 2016; 188: 635 - 651.

Comparison of Modern 3D and 2D MR Imaging Sequences of the Wrist at 3 Tesla

PURPOSE

To compare the image quality of modern 3 D and 2 D sequences for dedicated wrist imaging at 3 Tesla (T) MRI.

MATERIALS AND METHODS

At 3 T MRI, 18 patients (mean age: 36.2 years) with wrist pain and 16 healthy volunteers (mean age: 26.4 years) were examined using 2 D proton density-weighted fat-saturated (PDfs), isotropic 3 D TrueFISP, 3 D MEDIC, and 3 D PDfs SPACE sequences. Image quality was rated on a five-point scale (0 - 4) including overall image quality (OIQ), visibility of important structures (cartilage, ligaments, TFCC) and degree of artifacts. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) of cartilage/bone/muscle/fluid as well as the mean overall SNR/CNR were calculated using region-of-interest analysis. ANOVA, paired t-, and Wilcoxon-signed-rank tests were applied.

RESULTS

The image quality of all tested sequences was superior to 3 D PDfs SPACE (p < 0.01). 3 D TrueFISP had the highest combined cartilage score (mean: 3.4) and performed better in cartilage comparisons against 3 D PDfs SPACE in both groups and 2 D PDfs in volunteers (p < 0.05). 3 D MEDIC performed better in 7 of 8 comparisons (p < 0.05) regarding ligaments and TFCC. 2 D PDfs provided constantly high scores. The mean overall SNR/CNR for 2 D PDfs, 3 D PDfs SPACE, 3 D TrueFISP, and 3 D MEDIC were 68/65, 32/27, 45/47, and 57/45, respectively. 2 D PDfs performed best in most SNR/CNR comparisons (p < 0.05) and 3 D MEDIC performed best within the 3 D sequences (p < 0.05).

CONCLUSION

Except 3 D PDfs SPACE, all tested 3 D and 2 D sequences provided high image quality. 3 D TrueFISP was best for cartilage imaging, 3 D MEDIC for ligaments and TFCC and 2 D PDfs for general wrist imaging.

KEY POINTS

• 3 D TrueFISP is recommended for cartilage imaging of the wrist at 3 T.• 3 D MEDIC is recommended for ligaments and TFCC.• Robust 2 D PDfs should be used in routine protocols. 3 D sequences may be added depending on the clinical question.• 3 D PDfs SPACE is currently inferior. Citation Format: • Rehnitz C, Klaan B, von Stillfried F et al. Comparison of Modern 3D and 2D MR Imaging Sequences of the Wrist at 3 Tesla. Fortschr Röntgenstr 2016; 188: 753 - 762.

[Osteoidosteoma. From diagnosis to treatment]

An osteoid osteoma is a benign bone-forming tumor which usually presents in childhood and adolescence and is characterized by extensive nocturnal pain. Computed tomography (CT) is used to reveal the typical radiolucent nidus surrounded by a sclerotic reaction and in magnetic resonance imaging (MRI) a nidal enhancement and perifocal edema can confirm the diagnosis. Having shown excellent success rates radiofrequency ablation has become the treatment of choice which allows minimally invasive and precise destruction of nidal tumor tissue. By using thermal protection techniques and multiple ablation positions successful therapy of perineural tumors and niduses with diameters of more than 2 cm are possible.

[Clinical or radiological diagnosis of impingement]

CLINICAL/METHODICAL ISSUE

Shoulder impingement syndrome is a clinically common entity involving trapping of tendons or bursa with typical clinical findings.

STANDARD RADIOLOGICAL METHODS

Important radiological procedures are ultrasound, magnetic resonance imaging (MRI) and MR arthrography. Projection radiography and computed tomography (CT) are ideal to identify bony changes and CT arthrography also serves as an alternative method in cases of contraindications for MRI. These modalities support the clinically suspected diagnosis of impingement syndrome and may identify its cause in primary diagnosis. In addition, effects of impingement are determined by imaging. Therapy decisions are based on a synopsis of radiological and clinical findings.

PERFORMANCE

The sensitivity and specificity of these imaging modalities with regard to the diagnostics of a clinically evident impingement syndrome are given in this review article.

PRACTICAL RECOMMENDATIONS

Orthopedic and trauma surgeons express the suspicion of an impingement syndrome based on patient history and physical examination and radiologists confirm structural changes and damage of intra-articular structures using dedicated imaging techniques.

Modern Radiological Postoperative Diagnostics of the Hip Joint in Children and Adults

The assessment of bone healing and loosening of endoprosthesis material was long the primary indication for postoperative projection radiography and CT imaging of the hip joint following trauma and endoprosthesis implantation. With the increasing number of joint-preserving surgery, e. g. of surgical hip luxation and hip arthroscopy for the treatment of femoroacetabular impingement (FAI), high-resolution imaging of intra-articular pathologies before and after surgery has become increasingly important. In this review article, diagnostic imaging of the hip joint is presented following common trauma surgery and orthopedic surgery interventions. The imaging modalities of projection radiography, CT and MRI including direct MR-arthrography are discussed with regard to their diagnostic capability in the postoperative assessment of the hip joint. Among others topics, imaging is discussed following hip arthroplasty, following surgical hip luxation and arthroscopic interventions for the treatment of FAI, as well as following core decompression for avascular necrosis of the femoral head. Moreover, orthopedic interventions of the hip joint in children and adolescents are presented and the dedicated reporting of postoperative imaging is outlined.

KEY POINTS

• Consolidation of osteotomies and position of implants should be assessed in postoperative imaging. • MRI is useful for confirming correct articulation after treatment of congenital hip dislocation. • Radiologically assessable complications after total hip replacement are inlay wear, loosening, dislocation, periarticular ossifications and infection. • MRI can detect and classify pseudotumours in cases of metal-metal pairing after total hip replacement.

[Imaging of the elbow joint with focused MRI. Part 1: examination techniques and sequences for bone and ligaments]

Imaging of the elbow joint places high demands on the quality of imaging due to the challenging anatomy and the sometimes subtle findings. For the diagnosis of periarticular soft tissues, ligamentous structures and in individual cases for fracture and tumor diagnosis, magnetic resonance imaging (MRI) is mostly groundbreaking and allows a reliable diagnosis in most cases. This review article discusses the complex imaging anatomy and anatomical variants of this joint and the most common osseous and ligamentous injuries of the elbow joint are presented. The typical MRI findings and indications are illustrated and discussed and possible pitfalls are pointed out. The various examination techniques and MRI sequences are also addressed.

[Aseptic osteonecrosis in children and adolescents]

BACKGROUND

Aseptic osteonecrosis (AO) in children and adolescents has been described in all parts of the skeleton. The disease is presumed to be caused by local blood circulation disorders, the reasons for which are multifactorial and occur more often in times of stronger growth intensity.

DISEASE SEQUELAE

The disease leads to bone catabolism which can affect the epiphyses, metaphyses, apophyses, carpal and tarsal bones of the hands and feet. The more stretched the form alteration of the bone at the end of the diseases is, the earlier arthritic alterations occur due to the incongruence of the corresponding joint partner. If a growth plate is affected, a growth disorder can be the result.

DIAGNOSTICS AND THERAPY

The diagnostics and therapeutic measures are oriented to the site and extent of the disease and the age of the child. For early forms of AO magnetic resonance imaging (MRI) is the imaging method of choice. In recent years the medicinal therapy of AO has been described as an additional option. The disease lasts at least several months up to years and more commonly affects boys than girls with the exception of necrosis of the foot tarsals.

CONCLUSION

The early diagnosis and immediate initiation of adequate therapy which must take the age and stage of the disease into consideration, can reduce a possible joint destruction. Prostaglandin therapy, as an off label use, leads to a reduction of pain and improvement in mobility.

Prevalence of carpal tunnel syndrome and wrist osteoarthritis in long-term paraplegic patients compared with controls

We compared functional and structural changes in the hands, in particular the prevalence of carpal tunnel syndrome, in 56 paraplegic patients who had been wheelchair dependent for over 25 years with a group of able-bodied volunteers (with matching criteria for gender and age). The hands were assessed by clinical examination, electrophysiology, disabilities of the arm shoulder and hand score and magnetic resonance imaging. Hand function was worse and wrist pain was experienced more often in the paraplegic patients, and they also had a significantly higher prevalence of carpal tunnel syndrome both clinically and electrophysiologically. The prevalence of wrist and trapeziometacarpal osteoarthritis was significantly higher in the right hand.