[Importance of SPECT/CT for knee and hip joint prostheses]. / Stellenwert der SPECT/CT bei Knie- und Hüftgelenkprothesen.

CLINICAL/METHODICAL ISSUE: Complications, such as loosening or infections are common problems after hip or knee arthroplasty. STANDARD RADIOLOGICAL METHODS: If conventional X-rays are equivocal bone scintigraphy is the classical second-line imaging modality. METHODICAL INNOVATIONS: Single photon emission computed tomography/computed tomography (SPECT/CT) offers metabolic and morphologic information in one imaging step and is becoming increasingly more available in larger hospitals. PERFORMANCE: The SPECT/CT procedure is a promising method and is increasingly being used in daily routine to evaluate joint arthroplasty. The additional benefit compared with classical conventional bone scintigraphy has to be evaluated in further prospective studies. ACHIEVEMENTS: In our hospital SPECT/CT regularly gives important additional information regarding prosthetic joint complications. PRACTICAL RECOMMENDATIONS: SPECT/CT is increasingly being used as the second step imaging standard modality if conventional X-rays are equivocal.

Pseudoaneurysm rupture after liver injury in a 14-year-old boy.

Today, haemodynamically stable children with blunt liver trauma are treated conservatively and can be discharged from hospital within one week. We report on a 14-year-old boy with a blunt hepatic trauma grade III, who showed a pseudoaneurysm with active bleeding into the abdominal cavity after mobilisation on day 9. Supraselective angiography of the right hepatic artery was performed and 2 titanium coils and gelatine sponge particles were placed for embolisation. In view of this complication, we suggest carrying out colour Doppler sonographic imaging to rule out pseudoaneurysm in children with blunt hepatic trauma before they are discharged from hospital.

Metabolic characterization of breast tumors with positron emission tomography using F-18 fluorodeoxyglucose.

PURPOSE: To evaluate the diagnostic value of position emission tomographic (PET) imaging with F-18 fluorodeoxyglucose (FDG) in differentiating between benign and malignant breast tumors. PATIENTS AND METHODS: Fifty-one patients, with suspicious breast lesions newly discovered either by physical examination or by mammography, underwent PET imaging before exploratory surgery. FDG-PET images of the breast were analyzed visually and quantitatively for objective assessment of regional tracer uptake. RESULTS: Primary breast cancer was identified visually with a sensitivity of 68% to 94% and a specificity of 84% to 97% depending on criteria used for image interpretation. Quantitative analysis of FDG uptake in tumors using standardized uptake values (SUV) showed a significant difference between benign (1.4 +/- 0.5) and malignant (3.3 +/- 1.8) breast tumors (P < .01). Receiver operating characteristic (ROC) curve analysis exhibited a sensitivity of 75% and a specificity of 100% at a threshold SUV value of 2.5. Sensitivity increased to 92% with a corresponding specificity of 97% when partial volume correction of FDG uptake was performed based on independent anatomic information. CONCLUSION: PET imaging allowed accurate differentiation between benign and malignant breast tumors providing a high specificity. Sensitivity for detection of small breast cancer ( < 1 cm) was limited due to partial volume effects. Quantitative image analysis combined with partial volume correction may be necessary to exploit fully the diagnostic accuracy. PET imaging may be helpful as a complimentary method in a subgroup of patients with indeterminate results of conventional breast imaging.

FDG PET evaluation of granular cell tumor of the breast.

Granular cell tumor is a rare, usually benign neoplasm of neural origin that may arise in virtually any site and, when situated in the breast, can mimic breast carcinoma. We describe a case of granular cell tumor of the breast in a 57-yr-old woman. Clinical evaluation, mammography, sonography and MRI suggested a carcinoma with infiltration of skin and muscle. However, the tumor did not display increased glucose metabolism on PET. Clinical findings, imaging results, histological characteristics and surgical management are discussed.

Computed tomographic demonstration of venous thrombosis of different etiologies.

Typical computed tomographic signs of venous thrombosis include the demonstration of the hypodense center (20 to 45 HU) in the involved blood vessel with a hyperdense margin surrounding it. CT represents a reliable method of diagnosis complimentary to that achieved by venography. CT examination allows the visualisation of the proximal end of the thrombus and gives the etiology of the thrombus. Venous thromboses occurring for the first time demonstrate a well defined borderline around the vein with a lack of reaction in the surrounding tissue. On the other hand, recurrent venous thrombosis is characterized by an inhomogenous zone of higher density in the perivascular region. A similar image can be obtained in secondary thrombosis due to inflammatory changes from adjacent tumours. In cases of thrombosis with tumour involvement, the tumour can be demonstrated.

MR in the diagnosis of bone tumours.

Forty-two patients with benign as well as malignant bone tumours or with tumour-like lesions of bone were evaluated using MR tomography. The appropriate choice of examination parameters is an essential prerequisite for the adequate visualisation and the definitive verification of the presence of a tumour. By means of its multi-planar display, MR provides definite advantages in the determination of tumour localisation and extension as well as in differentiating intra-tumoural haemorrhage from surrounding, non-involved tissue. In addition, the clear delineation of neighbouring structures such as muscular compartments and blood vessels achieved in MR can be useful in the planning of an eventual surgical approach. This new technique has proved itself superior to other available imaging modalities in the differentiation of residual or recurrent tumour from post-operative changes. A characterisation of the nature or histology of a suspicious lesion on the basis of relaxation-times or signal intensities, however, is not yet possible.

The effects of fluid-mechanical factors on MR imaging in the arterial model.

Blood flow is a significant factor in MR imaging. The purpose of this investigation was to study fluid-mechanical effects on MR imaging. MR images generated by the pulsatile flow of bovine blood in an elastic model of the aorta with both renal arteries were studied. The high-frequency pulse sequence was synchronized to an ECG trigger signal. It was demonstrated that different flow velocities, laminar and turbulent flow, and backward flow can be visualized with MR imaging.

MR-tomography in the diagnosis of malignant soft-tissue tumours.

Nine patients with malignant, peripheral soft-tissue tumours were examined using a 0.35 T MR equipment. In 7 cases in which tumour presence was surgically verified, a definite identification as well as an exact determination of tumour extension was achieved using MR. The various tumours exhibited a particularly high degree of contrast when using a T2-weighted Spin-Echo-(SE) as well as the T1-weighted Inversion-Recovery-(IR) mode. The T1- and T2-relaxation times of the soft-tissue malignancies evaluated in this study were markedly longer than those obtained for normal tissue. In 2 patients within the collective, a definite exclusion of tumour recurrence was possible.

[CT findings in calcified pseudotumors in hemodialysis patients]. / CT-Befunde bei verkalkten Pseudotumoren bei Hämodialysepatienten.

Three patients undergoing haemodialysis, who had extensive calcified pseudo-tumours, were examined by computer tomography. In two patients bone destruction was present, which was obscured by the calcification on conventional radiographs. In one patient an abscess in the vicinity of the pseudo-tumour was discovered by CT. CT enables exact localisation of the calcified areas to be achieved and aids therapy.

[Typical computed tomographic findings in neurofibromatosis]. / Typische computertomographische Befunde bei der Neurofibromatose.

Three patients with neurofibromatosis (Recklinghausen's disease) were examined by computer tomography. In this way, the exact extent and localisation of the neurofibromatous tumours could be demonstrated. In one patient, CT provided evidence of malignant change; this was verified histologically. The appearances of neurofibromatosis associated with elephantiasis is described. In each patient, treatment was significantly influenced by computer tomography.

[Findings of NMR tomography in the diagnosis of osteomyelitis and arthritis]. / Ergebnisse der MR-Tomographie in der Diagnostik der Osteomyelitis und Arthritis.

The findings on MR tomography in fourteen patients with osteomyelitis and eight patients with arthritis are described. A retrospective analysis showed that MR was superior in demonstrating changes in the bone marrow and spread of infection round the bone. These changes are shown more accurately and with better contrast after the use of gadolinium DTPA. T1 and T2 sequences appear to be necessary.

[Digital mammography: experiences in its clinical application]. / Digitale Mammographie: Erfahrungen bei klinischer Anwendung.

TARGET: In 1989 in the Cantonal Hospital of Lucerne conventional film-screen mammography was replaced by digital mammography. With the support of a retrospective study, it was checked whether or not digital mammography represents an equally valid diagnostic procedure in daily routine. METHODS: 1204 patients were examined using digital mammography. A reevaluation of these patients was carried out using clinical and radiological routine controls. Additionally a radiological and histological examination was performed in 127 cases in which excisional biopsies had been done, paying particular attention to detail perception. RESULTS: The sensitivity of digital mammography achieved a total of 85%, whereas the accuracy was 81%. With additional use of ultrasound and galactography the sensitivity attained 91%. By reevaluation the sensitivity amounted to 87%, the accuracy remaining at 81%. The positive predictive value was especially high with 76% and 77%. CONCLUSION: Digital mammography offers satisfactory diagnostic performance.

[Magnetic resonance tomography (MRT) in the diagnosis of Failed Back Surgery Syndrome (FBSS)]. / Die Magnetresonanztomographie (MRT) in der Diagnostik des Failed Back Surgery Syndroms (FBSS).

MRT was performed, using a 0.5 and 1.5 Tesla magnet, on 150 patients with FBSS between three days and 23 years following lumbar disc surgery. T1-weighted spin echo sequences were obtained before and after the application of gadolinium (0.15 mmol/kg). In 67 patients the MRT findings were compared with surgical observations. MRT had a sensitivity of 94% in diagnosing recurrent prolapse, a specificity of 100% and accuracy of 94%. The ventral epidural scar tissue, the disc and the neighbouring vertebral bodies showed increased contrast uptake over a prolonged post-operative period.

[The MRT of the breast with 2D-spin-echo and gradient-echo sequences in diagnostically problematic cases]. / MRT der Mamma mit 2D-Spinecho- und Gradientenecho-Sequenzen in diagnostischen Problemfällen.

One or both breasts of 296 patients with equivocal clinical or mammographic findings were examined with MRI. T1-weighted spin-echo (SE) and gradient-echo (FFE) sequences were acquired before and after i.v. application of Gadolinium DTPA. 50 lesions with enhancement after Gd-DTPA were biopsied--26 carcinomas, 17 proliferating mastopathic tissues, 5 fibroadenomas and 1 abscess were found. Contrast enhanced MRI with 2D-SE and FFE sequences is an effective technique for evaluating suspicious breast lesions with high diagnostic accuracy.

[Magnetic resonance tomography in the assessment of anterior cruciate ligament reconstruction by tendon grafts]. / Die Kernspintomographie zur Beurteilung des vorderen Kreuzbandersatzes mit Sehnentransplantaten.

150 patients were examined via magnetic resonance (MR) after anterior cruciate (ACL) ligament reconstruction (76 patellar tendon grafts, 53 semitendinous tendon grafts and 21 sutures). The results of MR were compared with clinical tests (Lachman, pivot-shift and anterior drawer test), in 2 cases with the operative findings, and in one case with arthroscopy findings. In 91% of patients with a clinically stable knee we found a continuous low-intensity ligamental structure. 10 patients were examined twice or more between 8 days and 6 months after surgery. Ligamental structures of low signal intensity did not significantly change their MR characteristics. MR is a valuable noninvasive method for evaluating ligament reconstructions.

[Computer tomographic findings in pelvic and abdominal trauma (author's transl)]. / Computertomographische Symptomatologie des Becken- und Bauchtraumas.

Twenty-two patients with trauma to the pelvis and abdomen were examined by computer tomography. Subcapsular haematomas, haematomas and rupture of organs, intra- and retroperitoneal haematomas and pelvic fractures could be reliably diagnosed in this way. Serial observations on the tissue density of an haematoma allows one to judge its age. Lack of contrast enhancement of an haematoma makes the injection of contrast a useful test. Computer tomography has reduced the indications for angiography in blunt abdominal trauma.

[DSA of the pulmonary vessels during endobronchial laser- and afterloading therapy of malignant bronchial stenoses]. / DSA der Pulmonalgefässe bei endobronchialer Laser- und Afterloadingtherapie maligner Bronchusstenosen.

The findings are reported of the DSA examination of the pulmonary vessels in 16 patients with malignant bronchial stenoses, for whom laser or after-loading therapy was being considered. In these patients an improvement of dyspnoea can be expected only of there is adequate perfusion of the involved lung segment. DSA demonstrated stenoses or occlusions of main pulmonary or lobar arteries in six patients. Ten patients had a normal pulmonary circulation. In most cases the result of the DSA examination was important in determining treatment.

[Applicability of nuclear spin tomography to heart diseases]. / Einsatzmöglichkeiten der Kernspintomographie bei Erkrankungen des Herzens.

Thirty-one patients with abnormalities of the heart and ten controls were examined by ECG-triggered nuclear resonance tomography. All patients had previously been completely investigated. Chamber sizes and mural thickness could be reliably demonstrated and, in addition, it was possible to show areas which could not be easily investigated by echocardiography. Visualisation of the valves was limited, but intra- and para-cardial lesions could be differentiated by a double echo technique. Absence and defects of septa could be shown exactly, as well as accurate demonstration of the relationship of the large vessels to the cardiac chambers.

[Teleradiology for emergency cranial computed tomography]. / Teleradiologie bei notfallmässigen Schädel-CT-Untersuchungen.

PURPOSE: We report our experience with the teleradiologic service provided by a center hospital (CH) for emergency cranial computed tomography (CCT) in two regional hospitals (RH) during a 12-month period. The clinical and economic impact of teleradiology will be discussed as well as the acceptance by the clinicians of the regional hospitals. MATERIAL AND METHODS: In 2001, 213 CT-scans in 202 patients were performed and reported using teleradiology. Teleradiologic and final medical diagnosis were analysed by the medical reports. The transfer of the patients to a CH and their further treatment were checked. The referring physicians in the RH were asked to complete a questionnaire about the teleradiological support. RESULTS: 18 (9 %) patients had to be urgently transferred to a CH based on the CT findings in the teleradiological reports. 24 patients (11 %) were transferred to a center hospital during further treatment. 80 % of patients were treated in the RH. CONCLUSION: CT data transfer is reliable and efficient. Teleradiology reduces costs by avoiding unnecessary transport of patients for diagnostic procedures. Teleradiology improves patient management by reducing time from admittance to decide about further treatment. Teleradiology enables rapid selection of the best-equipped center hospital for the management of the patient's disease. Teleradiology is well accepted by the physicians in the RH. In the RH, teleradiology has become an indispensable standard procedure in the emergency diagnostic workup of cerebral trauma patients and in patients with acute unclear neurological symptoms.