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.