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.

Correction to: Perfusion MRI in CNS disease: current concepts.

The above article was published with one author name being incorrect. The published paper states "H. von Tengg", whereas it should be "H. von Tengg-Kobligk". The author name has been corrected above.

[Dental X-ray diagnostics with the orthopantomography - Technique and typical imaging results]. / Dentale Röntgendiagnostik mit der Panoramaschichtaufnahme ­ Technik und typische Bildbefunde.

Despite the increasing use of modern digital cross-sectional imaging techniques (especially digital volume tomography) in dental X­ray 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 X­ray 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 X­ray 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 X­ray 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.

[Imaging of chronic inflammatory bowel diseases in childhood and adolescence : Repetitorium]. / Bildgebung chronisch-entzündlicher Darmerkrankungen im Kindes- und Jugendalter : 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]. / Chronische nichtbakterielle Osteomyelitis : Bildgebung und Differenzialdiagnosen.

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.

[Fracture classification-part 1 : Modern low-dose radiation imaging in pediatric traumatology]. / Frakturklassifikation ­ Teil 1 : Moderne strahlensparende Diagnostik in der Kindertraumatologie.

BACKGROUND: Fractures in children are significantly more common than bone fractures in adults. Overall, they have a good prognosis regarding spontaneous correction and a restitutio ad integrum. The aim of this study is to provide an overview of established modern (low-dose radiation) imaging techniques in pediatric fractures. MATERIALS AND METHODS: Knowledge of typical fractures for different ages, of the individual bone nuclei of the growth plate, and epiphyseal injuries are important for the correct radiological diagnosis. This review also focuses on fractures of the elbow because misinterpretation may result in delays of consolidation with subsequent growth disturbances, joint dysfunctions, and malpositions. RESULTS AND CONCLUSIONS: In addition to conventional x­rays, fracture sonography is becoming increasingly important for the detection of fractures in children. In the upper extremity, a sensitivity of 96% and specificity of 97% can be achieved for some fracture entities, e.g., at the distal forearm. Computed tomography is used restrictively but plays an important role in a few special indications for polytraumatized children and preoperative assessment, e.g., in the case of transitional fractures.

[Osteitis pubis or symphysitis pubis]. / Osteitis pubis oder Symphysitis pubis.

CLINICAL/METHODICAL ISSUE: Osteitis pubis is one of the most common causes of chronic groin pain in many professional athletes. Symphysitis pubis with instability of the joint due to softening of the joint capsule and muscular imbalance of the corresponding muscles increases the instability of the sympyseal region, thus, resulting in a vicious cycle. STANDARD RADIOLOGICAL METHODS: Magnetic resonance imaging (MRI). METHODICAL INNOVATIONS: Optimized MRI sequence protocol with oblique (axial oblique) layers parallel to the linea arcuata of iliac bone together with large image field for depiction of the entire pelvis and high-resolution sequences focused on the symphysis pubis. PERFORMANCE: Recently, the correlation between MRI signs of osteitis pubis and long-term clinical outcome in a group of professional soccer players was examined. In particular, edema in the peri-osseous tissue and isolated muscle lesions around the symphysis at the onset of symptoms were associated with partial recovery of the athletes. Furthermore, a significant association of increased normalized signal intensity in the pubic bone on STIR (short-tau inversion recovery) sequences (corresponding presence and signal intensity of bone marrow edema) and a poor complete clinical improvement was observed. ACHIEVEMENTS: An optimized MRI protocol allows the diagnosis of osteitis pubis and provides important prognostic information. PRACTICAL RECOMMENDATIONS: In case of clinical suspicion on osteitis pubis, MR imaging with an optimized sequence protocol should be performed.

[Osteoarthritis classifications : Modification proposal for the criteria of Kellgren and Vallotton]. / Arthrose-Klassifikationen : Modifizierungsvorschlag für die Kriterien nach Kellgren und 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. X­ray 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 X­ray 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).

[MR and CT arthrography in cartilage imaging : Indications and implementation]. / MR- und CT-Arthrographie zur Knorpeldiagnostik : Indikationen und Durchführung.

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.

[Magnetic resonance imaging following cartilage repair of focal chondral lesions]. / Postoperative Bildgebung fokaler Knorpeldefekte mittels Magnetresonanztomographie.

BACKGROUND: Focal cartilage lesions are common pathologies of weight-bearing joints. Clinical presentation ranges from asymptomatic patients to severe, pain-related movement deficits. Moreover, focal chondral lesions are risk factors for the development of osteoarthritis. There are various treatment options involving both surgical and nonsurgical treatments. Musculoskeletal radiologists should be aware of the various surgical options as well as the postsurgical imaging characteristics to depict whether the encountered imaging findings reflect the normal postoperative course or are indicative of a treatment failure. OBJECTIVES: We aim to describe the most common surgical procedures for the repair of focal cartilage lesions and their typical postsurgical appearance on MRI studies. MATERIALS AND METHODS: The literature in PubMed was searched with the terms "focal articular cartilage lesions", "chondral lesions", "MOCART", "Microfracture", "Osteochondral Autograft Transfer", "mosaicplasty", "Osteochondral Allograft Transplantation", "OATS", "OCT", "Autologous Chondrocyte Implantation", "ACI", "Matrix-Assisted Chondrocyte Implantation", "Autologous Matrix-induced Chondrogenesis". RESULTS: Surgical methods for the treatment of focal cartilage lesions as well as the MR imaging features are explained.

[Certification in cardiology : Contra: The concept should be improved]. / Zertifizierungen in der Kardiologie : Kontra: Das Konzept sollte verbessert werden.

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.

[Diagnostic imaging of drug-induced osteonecrosis of the jaw]. / Bildgebende Diagnostik bei medikamenteninduzierten Kiefernekrosen.

Drug-induced osteonecrosis of the jaw represents a relatively new, multifactor-induced disease. Diseases with increased bone resorption are widely treated with antiresorptive drugs. Due to the active bone metabolism, especially in the lower jaw, it can lead to osteonecrosis if the barrier function in the oral cavity is impaired and it may be complicated by systemic comorbidities depending on duration, intensity, and application of antiresorptive therapy. Due to the special influence of these changes on the quality of life and because of the complex therapy management, the early detection and determination of the extent of the lesion(s) by imaging is of particular importance. The orthopantomography (panoramic radiography) of the jaw provides a good basic examination, especially for the detection of dental causes as a possible differential diagnosis. Three-dimensional imaging techniques such as computed tomography and in particular magnetic resonance imaging can detect bone changes much more sensitively and detect the manifestation of complex pathologies in higher stages of disease.

[Ultrasound of the elbow-standard examination technique and normal anatomy]. / Sonographie des Ellenbogens ­ Standardschnitte und Normalanatomie.

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.

[CEUS-application possibilities in the musculoskeletal system]. / CEUS ­ Einsatzmöglichkeiten am Bewegungsapparat.

METHODICAL ISSUE: Contrast-enhanced ultrasound (CEUS) offers easily accessible visualization and quantification of the skeletal muscle microcirculation and other tissues in vivo and in real-time with almost no side effects. AIM: The aim of this review is to present the increasing number of musculoskeletal CEUS applications. METHODICAL INNOVATIONS/PERFORMANCE: CEUS applications regarding the musculoskeletal system include applications at bone and joints extending beyond the visualization of only the muscular microcirculation. Besides basic muscle physiology, impaired microcirculation in patients with peripheral artery disease or diabetes mellitus and the diagnosis of inflammatory myopathies have been the subject of previous CEUS studies. More recent studies in orthopedics and traumatology have focused on osseous and muscular perfusion characteristics, e. g., in differentiating infected and aseptic non-unions or the impact of different types of implants and prostheses on muscular microcirculation as a surrogate marker of clinical success. PRACTICAL RECOMMENDATIONS: CEUS of the musculoskeletal system is used in clinical trials or off-label. Therefore, it is not well established in clinical routine. However, considering the increasing number of musculoskeletal CEUS applications, this could change in the future.

[Injuries of ligaments and tendons of foot and ankle : What every radiologist should know]. / Band- und Sehnenverletzungen an Fuß und Sprunggelenk : Was jeder Radiologe wissen sollte.

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 X­ray 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.

[Focal lesions in whole-body MRI in multiple myeloma : Quantification of tumor mass and correlation with disease-related parameters and prognosis]. / Fokale Läsionen in der Ganzkörper-MRT beim multiplen Myelom : Quantifizierung der Tumorlast und Korrelation mit krankheitstypischen Parametern und Prognose.

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.

[Imaging diagnostics in bone metastases]. / Bildgebende Diagnostik bei Skelettmetastasen.

Bone metastases are common, can cause a variety of relevant symptoms and are often associated with a poor prognosis. An early and accurate diagnosis is therefore crucial; however, the pattern is very heterogeneous and necessitates good knowledge of the possibilities and limitations of each imaging modality. Magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET/CT) have the highest sensitivity and specificity for detecting bone metastases. Gradient echo and diffusion-weighted sequences are valuable supplements to the MRI protocol in doubtful cases and MRI is particularly suitable for distinguishing osteoporotic from metastatic spinal fractures with a high degree of diagnostic certainty; however, CT is the modality of choice for stability assessment. Reliable imaging parameters to predict therapy response in cases of bone metastases have not yet been elucidated in large clinical trials. The PET/MRI approach has shown promising preliminary results for diagnosis of bone metastases and further studies in larger cohorts are the subject of ongoing studies.

[Neurogenic myopathies and imaging of muscle denervation]. / Neurogene Myopathien und Bildgebung der Muskeldenervation.

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.

[Incidental findings in musculoskeletal radiology]. / Zufallsbefunde in der muskuloskeletalen Radiologie.

BACKGROUND: Increasing numbers of conventional X­rays, computed tomography and magnetic resonance imaging in the inpatient, outpatient and scientific routine leads to an increasing number of incidental findings. The correct interpretation of these incidental findings with respect to the relevance and the evaluation concerning further work-up is an important task of radiologists. OBJECTIVE: Description of common incidental findings in musculoskeletal imaging and their clinical classification. MATERIAL AND METHODS: A PubMed literature search was performed using the following terms: incidental findings, population-based imaging, musculoskeletal imaging, non-ossifying fibroma, enchondroma, osteodystrophia deformans, chondrosarcoma, fibrous dysplasia, simple bone cyst, unicameral bone cyst, solitary bone cyst, aneurysmal bone cyst, vertebral hemangioma, bone island, osteopoikilosis, Tarlov cyst and diffuse idiopathic skeletal hyperostosis (DISH). RESULTS: Incidental findings are observed in up to 40% of imaging procedures. In up to 6% these incidental findings involve the skeletal system. Common incidental findings are discussed and their clinical relevance is explained.