Radiologic diagnosis before and after liver transplantation]

The main function of imaging procedures before liver transplantation is the exclusion of factors that may either constitute contraindications to surgery or necessitate a modification of the operation technique. Ultrasound and MRI are the modalities best suited for this purpose. After transplantation, imaging procedures are required mainly for diagnosis of and differentiation, in particular, between vascular and biliary complications, rejection, and infection, since these postoperative complications very often cannot be reliably differentiated on the basis of clinical and laboratory parameters alone. As vascular disturbances can vary widely in their presentation and can mimic other complications, duplex Doppler sonography plays a dominant role in clarification of the perfusion status of the graft. If infection is suspected, ultrasound generally has to be supplemented by other imaging procedures such as CT or MRI; if these techniques reveal suggestive lesions, a fine-needle aspiration is mandatory in most cases. Invasive procedures such as angiography or PTC are now applied only in selected cases, especially if an intervention is contemplated. Rejection cannot be reliably diagnosed by any of the imaging techniques and still requires biopsy.     

Angeborene Fehlbildungen der Aorta im Kindes- und Jugendalter

Aortic abnormalities are common cardiovascular malformations accounting for 15-20% of all congenital heart disease. Ultrafast CT and MR imaging are noninvasive, accurate and robust techniques that can be used in the diagnosis of aortic malformations. While their sensitivity in detecting vascular abnormalities seems to be as good as that of conventional catheter angiocardiography, at over 90%, they are superior in the diagnosis of potentially life-threatening complications, such as tracheal, bronchial, or esophageal compression. It has been shown that more than 80% of small children with aortic abnormalities benefit directly from the use of noninvasive imaging: either cardiac catheterization is no longer necessary or radiation doses and periods of general anesthesia for interventional catheterization procedures can be much reduced.The most important congenital abnormalities of the aorta in children and adolescents are presented with reference to examples, and the value of CT and MR angiography is documented.     

Moderne CT- und PET/CT-Bildgebung der Leber

Computed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI.     

Radiological evaluation of temporal bone disease: high-resolution computed tomography versus conventional X-ray diagnosis

Sixty-two patients with different temporal bone lesions were prospectively examined by high-resolution computed tomography (CT) and conventional plain radiography, including pluridirectional tomography. High-resolution CT enabled a clear diagnosis in 80% of cases, conventional radiology in 63%; 1.6-times more bone information was recorded by high-resolution CT which is clearly superior for imaging cholesteatomas, metastases and inflammatory processes and for evaluating osseous destruction. With regard to pathological soft tissue or effusions filling the tympanic cavities, conventional radiology shows poor sensitivity (0.61). High-resolution CT is the most sensitive method for the imaging and classification of temporal bone fractures, including labyrinthine damage and ossicular chain injuries. Only in cases of atypical fractures with an unfavourable relationship to the CT planes, can carefully directed tomography be more effective. In most cases high-resolution CT replaces conventional radiology and should be the method of choice for comprehensive radiological examination of the temporal bone.     

Untersuchungstechniken und Stellenwert der CT bei der Diagnostik von Herzklappenerkrankungen

Clinical/methodical issue

Cardiac computed tomography (CT) is the first-line modality for coronary assessment. In addition valvular morphology and function can be evaluated.

Standard radiological methods

The method of choice for the evaluation of cardiac valves is echocardiography, followed by magnetic resonance imaging.

Methodical innovations

Recent technical improvements and advances in temporal resolution allow a detailed anatomical and functional evaluation of the cardiac valves.

Performance

Cardiac CT provides an excellent image quality of the aortic and mitral valve thus enabling an evaluation of the morphology. In addition, cardiac CT allows an assessment of aortic valve function with respect to the grading of stenosis and regurgitation.

Achievements

Cardiac CT is not considered the first-line modality for the evaluation of cardiac valves; however, beyond coronary assessment CT provides important information on the morphology and function of cardiac valves.

Practical recommendations

Cardiac CT can be a useful imaging alternative for patients in whom other more commonly used methods, such as echocardiography and magnetic resonance imaging fail to provide the necessary information.     

Bildgebende Diagnostik der Kindesmisshandlung

Diagnostic imaging in child abuse plays an important role and includes the depiction of skeletal injuries, soft tissue lesions, visceral injuries in “battered child syndrome” and brain injuries in “shaken baby syndrome”. The use of appropriate imaging modalities allows specific fractures to be detected, skeletal lesions to be dated and the underlying mechanism of the lesion to be described. The imaging results must be taken into account when assessing the clinical history, clinical findings and differential diagnoses. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations must be performed in order to detect lesions of the central nervous system (CNS) immediately. CT is necessary in the initial diagnosis to delineate oedema and haemorrhages. Early detection of brain injuries in children with severe neurological symptoms can prevent serious late sequelae. MRI is performed in follow-up investigations and is used to describe residual lesions, including parenchymal findings.     

The role of CT in the management of adult urinary tract trauma

Computed tomography (CT) is now the investigation of choice for evaluating haematuria following major abdominal trauma. This pictorial review provides a logical framework for understanding the classification and features of urinary tract injuries, defines the indications and outlines the techniques for CT imaging in upper and lower urinary tract trauma. The use of other competing imaging modalities is also discussed.     

Traumatic injuries: imaging of peripheral musculoskeletal injuries

The current dominant role of conventional radiography must be reassessed at increasingly shorter intervals in view of the continuing emergence of new imaging modalities that are available to diagnose peripheral musculoskeletal injuries. In comparison with conventional radiography, digital radiographic techniques offer advantages for optimization of image quality and dose, such as a wider dynamic range and post-processing of images. Currently, digital luminescence radiography (storage phosphor radiography) is the most commonly used digital method for obtaining radiographs, using the established positioning projections and routines of the film-screen technique. A new process, radiography with flat-panel amorphous silicon detectors, is still under development. Computed tomography is a valuable tool for diagnosing injuries of the peripheral musculoskeletal system, especially when three-dimensional data sets are acquired; these allow reformating images in all planes desired (2D technique) or in a volumetric format (3D technique). Established indications for CT in the peripheral skeleton are hip fractures, wrist injuries and calcaneal fractures; however, CT may be used as a supplement to radiography in every region of the body. Sonography is beginning to play an increasingly important role in trauma. Muscle and tendon injuries are the most common indications, but worthwhile information can be gained of the shoulder, elbow, hip, and knee joints, supplementing conventional or digital radiography. Magnetic resonance imaging effectively visualizes traumatic changes of the skeleton and the peripheral soft tissues. It is the method of choice to detect occult fractures. It can be used to diagnose muscle and tendon injuries. Joint injuries, especially in the knee and the shoulder joint, are common indications for MRI in the posttraumatic setting.     

Volume-rendered three-dimensional spiral CT: musculoskeletal applications.

Spiral computed tomography (CT) is a powerful modality for evaluation of the musculoskeletal system, particularly when coupled with real-time, volume-rendering reconstruction techniques. Including volume-rendered spiral CT in routine musculoskeletal imaging protocols can change management in a significant number of cases. In cases of trauma, subtle fractures--particularly those oriented in the axial plane--are better seen on volume-rendered images. Complex injuries can be better demonstrated with volume-rendered images, and complicated spatial information about the relative positions of fracture fragments can be easily demonstrated to the orthopedic surgeons. The use of intravenously administered contrast material allows simultaneous evaluation of osseous and vascular structures within the affected area. Evaluation of suspected infectious or neoplastic disease is also aided by including volume-rendered imaging in the musculoskeletal spiral CT examination. The extent of disease can be thoroughly evaluated with volume-rendered images, and therapeutic planning--be it surgical or medical--is aided by the anatomic information available from volume-rendered images. Postoperative studies in patients with orthopedic hardware also benefit from volume-rendered imaging. Volume rendering eliminates most streak artifact and produces high-quality images on which the relationships among hardware, bones, and bone fragments are well demonstrated.     

Special diagnostic procedures in sports medicine

In summary, there are a number of imaging procedures available to support the physician in his or her evaluation of sports injuries. Conventional radiographs remain the primary imaging examination. Specialized radiographic projections will often provide additional pertinent information. A fluoroscopic examination or conventional tomography may provide a cost-effective method of clarifying subtle post-traumatic changes. The use of the more sophisticated and costly imaging procedures should be reserved for those cases in which a diagnosis cannot be made with simpler technology. CT scanning, by virtue of its ability to image in the axial plane, has proved to be an effective method of documenting injuries particularly in complex bony anatomy such as the spine, wrist, elbow, and hips. CT arthrography provides diagnostic information about intra-articular structures. MRI is emerging as an excellent method of noninvasively imaging injuries to soft-tissue structures such as tendons, ligaments, and cartilage. The advancements in MRI technology that are projected for the future may expand the range of usefulness of this modality and decrease the current high cost of these procedures. Radionuclide scanning with Tc99m diphosphonate compounds has proved to be an efficient method of localizing subtle bone pathology and providing a "road map" for further analysis with additional imaging techniques. The cost-effective use of all of these imaging procedures is predicated on an understanding of their usefulness in the diagnosis of each clinical problem and the judicious use of each procedure to fit the needs of the individual patient.     

The value of CT in the detection of bladder and posterior urethral injuries

To determine the value of CT in the diagnosis of bladder and posterior urethral injuries, we retrospectively evaluated the CT and urethrocystographic findings in 33 trauma patients with suspected injuries of the lower urinary tract who had both studies in their initial evaluation. In 26 (79%) of 33 patients, results of both examinations were normal. Seven (21%) of 33 patients had bladder injuries (seven--two in one patient) and/or posterior urethral injuries (three) as determined on the basis of urethrocystography. Three patients had extraperitoneal bladder tears as the only injury to the lower urinary tract. Two patients had both extraperitoneal bladder tears and posterior urethral injuries. One patient had both an extraperitoneal tear at the bladder base and an intraperitoneal rupture at the bladder dome. The seventh patient had an isolated posterior urethral injury. All seven bladder injuries were detected with CT. In these cases, CT findings included (1) free intraperitoneal contrast material (one case), (2) focal contrast extravasation (three cases), and (3) paravesical fluid collections that on delayed CT scans revealed contrast accumulation in the fluid, indicating extravasation (two cases). The seventh bladder injury was suspected on CT and confirmed with retrograde urethrography. Only one of three posterior urethral injuries was detected with CT. Our results suggest that CT is sensitive in the detection of bladder injuries, but not for the diagnosis of urethral injuries.     

CT of pelvic fractures

Although magnetic resonance imaging has become the dominant modality for cross-sectional musculo-skeletal imaging, the widespread availability, speed, and versatility of computed tomography (CT) continue to make it a mainstay of emergency room (ER) diagnostic imaging. Pelvic ring and acetabular fractures occur as the result of significant trauma secondary to either a motor vehicle accident or a high-velocity fall. These injuries are correlated with significant morbidity and mortality, both from the complications of pelvic ring fractures and from commonly associated injuries. The most commonly used classification of pelvic and acetabular fractures has been based on conventional radiographs that are, in the majority of cases, sufficient to determine the type of injury. However, because of the complexity of pelvic and acetabular fractures, precise pathological anatomy is not easily demonstrated by routine radiographs and in many cases details of fractures are not visible. Moreover, the insufficient co-operation of the patient or the difficulty of maintaining special positions can be overcome by using computed tomography. Spiral computed tomography provides information regarding the extent of the fractures and is complementary to radiography for ascertaining the spatial arrangement of fracture fragments. Spiral computed tomography is an effective tool for understanding complex fracture patterns, particularly when combined with multi-planar reconstruction two-dimensional (MPR 2D) reformatted images or three-dimensional images (3D) images. Including these techniques of reconstruction in routine pelvic imaging protocols can change management in a significant number of cases. Subtle fractures, particularly those oriented in the axial plane, are better seen on MPR images or 3D volume-rendered images. Complex injuries can be better demonstrated with 3D volume-rendered images, and complicated spatial information about the relative positions of fracture fragments can be easily demonstrated to the orthopaedic surgeons. The use of intravenous (i.v.) contrast material allows simultaneous evaluation of osseous and vascular structures within the affected area. Postoperative studies in patients with orthopaedic hardware also benefit from volume-rendered imaging. Volume rendering eliminates most streak artifact and produces high-quality images on which the relationships among hardware, bones, and bone fragments are well demonstrated.     

Bildgebende Methoden in der onkologischen Diagnostik

Cross-sectional imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) CT are an integral part of the modern oncological workup. They are used for tumor detection and staging as well as for treatment evaluation and monitoring. Due to pathophysiological and histological differences there is no universal imaging protocol for the assessment of different forms of cancer. For instance, CT is still the standard technique for the detection and staging of lung cancer supplemented by PET which aids the exclusion of nodal involvement and the detection of distant metastases. For hepatocellular carcinoma on the other hand, MRI is the preferred imaging technique, particularly when used in conjunction with liver-specific contrast media - PET/CT is only of limited value. Finally, for neuroendocrine tumors there is a focus on special radiotracers, which, in the context of PET/CT, enable a highly specific whole-body assessment. Thus, knowledge of the pathophysiological and imaging characteristics of different tumors is essential for a personalized, state-of-the art management of oncology patients.     

Duktales Adenokarzinom und ungewöhnliche Differenzialdiagnosen

Ductal pancreatic adenocarcinoma is by far the most common solid tumor of the pancreas. It has a very poor prognosis, especially in the more advanced stages which are no longer locally confined. Due to mostly unspecific symptoms, imaging is key in the diagnostic process. Because of the widespread use of imaging techniques, incidental findings are to a greater extent discovered in the pancreas, which subsequently entail further work-up. Ductal pancreatic adenocarcinoma can be mimicked by a large number of different lesions, such as anatomical variants, peripancreatic structures and tumors, rarer primary solid pancreatic tumors, cystic tumors, metastases or different variants of pancreatitis. Additionally, a number of precursor lesions can be differentiated. The correct classification is thus important as an early diagnosis of ductal pancreatic adenocarcinoma is relevant for the prognosis and because the possibly avoidable treatment is very invasive. All major imaging techniques are principally suitable for pancreatic imaging. In addition to sonography of the abdomen, usually the baseline diagnostic tool, computed tomography (CT) with its superior spatial resolution, magnetic resonance imaging (MRI) with its good soft tissue differentiation capabilities, possibly in combination with MR cholangiopancreatography (MRCP), endosonography with its extraordinary spatial resolution, conceivably with additional endoscopic retrograde CP or the option of direct biopsy and finally positron emission tomography CT (PET-CT) as a molecular imaging tool are all particularly useful modalities. The various techniques all have its advantages and disadvantages; depending on the individual situation they may need to be combined.     

Fehlbildungen und Missbildungen des Felsenbeins

High-resolution computed tomography (HRCT) is the procedure of choice in the diagnostics of abnormalities of the middle and inner ear. It allows a detailed presentation of anatomical features and achieves the prerequisites for selection of the various therapeutic options. The highly diverse abnormalities can be described using detailed imaging analyses. Malformations with an abnormally developed modiolus are assumed to be early embryological defects, such as the classical Mondini dysplasia. The essential therapeutic option for middle ear deformities is still a cochlear implant. The domain of magnetic resonance imaging (MRI) is not only in the analysis of the cochlear nerve and for exclusion of fibrosis or ossification of the labyrinth but is also able to visualize details of isolated malformations, such as an extended vestibular aqueduct or subtle alterations to the vestibule or can visualize them better in comparison to CT. Radiological diagnostics are used not only for classification but also to recognize typical clinical problem situations and play a key role in the diagnostics of hearing disorders and selection of the optimal therapeutic procedure.     

Tipps, Tricks und Fallstricke bei der Bildgebung von Myelonverletzungen

Over the last several decades the survival rate for acute spinal cord lesions has improved, which has resulted in an increased number of chronic spinal cord injuries. Magnetic resonance imaging (MRI) plays an essential role in imaging of the spinal cord, as it allows a detailed depiction of neural structures. However, the correct radiologic diagnosis is often complicated by the multitude of differential diagnoses. This article provides tips and tricks to achieve an accurate imaging report and details potential pitfalls in the interpretation of MR images. Acute spinal cord injuries show different characteristics which range from edema to intramedullary bleeding and to transsection. The spectrum of chronic spinal cord injuries encompasses myelomalacia, syrinx, cystic myelopathia and myeloatrophy. In addition to typical morphological features this article concentrates on the pathogenesis of injury patterns, on the use of appropriate contrast-enhanced MR sequences and on new MR techniques for the differentiation of individual pathologies.     

Multi-modality imaging of the leaking ureter: why does detection of traumatic and iatrogenic ureteral injuries remain a challenge?

Ureteral injuries are uncommon in trauma patients, accounting for fewer than 1% of all injuries to the urinary tract. These uncommon, yet problematic, injuries can often be overlooked in the standard search pattern on abdominal and pelvic multi-detector CT (MDCT) images, as radiologists focus on more immediate life-threatening injuries. However, early diagnosis and management are vital to reduce potential morbidity. If there is a high clinical index of suspicion for ureteral injuries with penetrating or blunt trauma, or if there is suspected iatrogenic ureteral injury, delayed-phase/urographic-phase MDCT images are essential for confirming the diagnosis. Moreover, making the distinction between partial and complete ureteral transection is critical, as it will guide management. The aim of this pictorial review is to overview the key imaging findings in blunt and penetrating traumatic and iatrogenic injuries of the ureter, as well as to discuss the advantages and disadvantages of different imaging modalities for accurately and rapidly establishing or excluding the diagnosis of ureteral injuries, with an emphasis on MDCT. The potential causes of missed ureteral injuries will also be discussed.     

CT Kolonographie: Techniken der Visualisierung und Befundung

Evaluation and interpretation of CT colonography is based on both 2D and 3D techniques. The 2D techniques are popular mainly because the time needed for evaluation is short. The 3D techniques allow better definition than the 2D techniques, especially of polyps close to folds or at the base of a fold. The evaluation strategies generally accepted so far (primarily 2D, with 3D for problem cases, or vice versa) demand knowledge of both 2D and 3D techniques. Newer 3D visualization techniques help make it possible to acquire more complete and faster recording particularly of areas that are not easily accessible to endoscopic examination. These user-friendly developments are thus well suited to improving the detection and the security of detection of polyps. It must be remembered that experience and the knowledge of associated artifacts and the limitations they can impose on diagnosis are prime requirements for the implementation of such visualization techniques.     

创伤骨科急诊入院病人漏诊与误诊的分析

探讨创伤骨科急诊人院病人漏误诊原因及防止措施。方法根据１９９７年１１０４例创伤骨科急诊入院病人的病历记录,对５７例６４处损伤初诊被漏诊或误诊进行统计分析,寻找与漏诊发生的相关因素。结果１１０４例创伤骨科急诊入院病人中,５７例６４处损伤初诊被漏诊或误诊,漏误诊率为５．１％。     

Skaphoidfraktur und -pseudarthrose

Scaphoid fractures, which involve approximately two-thirds of all wrist injuries, are often not detected during initial radiographic examination. By using high-resolution CT and dedicated MRI, it is possible to recognize scaphoid fractures soon at the first diagnostic approach and to assess fragment stability. CT imaging provides all the relevant information of the fracture extent and of the fracture healing in the follow-up. MRI is most sensitive in the detection of scaphoid fractures; however, fracture signs must be differentiated from those of a bone bruise. Both the initially overseen scaphoid fracture and the unsuccessful healing can lead to the natural history of scaphoid nonunion. In the injured scaphoid, CT imaging is essential for depicting the osseous morphology, whereas contrast-enhanced MRI is crucial for assessing the viability of the proximal fragment.