Treatment of long superficial femoral artery occlusions with excimer laser angioplasty: long-term results after 48 months.

PURPOSE: To evaluate clinical and hemodynamical long-term results after laser angioplasty of long occlusions of the superficial femoral artery (SFA). MATERIAL AND METHODS: In a prospective trial of 452 patients with long occlusions of the SFA, excimer percutaneous transluminal laser angioplasty (PTLA) for recanalization was applied. The average occlusion length of the SFA was 25.5 cm (range 16-38 cm). The recanalization attempt was done with the crossover technique in 398 patients, in 36 patients with the antegrade technique and in another 18 patients with the transpopliteal technique. RESULTS: The application of laser angioplasty demonstrated a successful recanalization of the SFA in 386/452 patients (85.5%). Recanalization with PTLA was not possible in 66 patients (14.5%). The main reason for the unsuccessful PTLAs was obstructing calcified material (n = 28) resistant to PTLA application. After a follow-up period of 48 months there was a primary, primary-assisted, and secondary patency rate of 22.3%, 40.9%, and 43.2%, respectively. CONCLUSION: Laser angioplasty of long occlusions of the SFA is a feasible procedure with a low failure rate. Long-term results are promising, but additional interventions are required in most patients if a patency rate of 43.2% is to be achieved after 4 years.

Magnetic Resonance Female Breast Imaging (MRFBI) - Evaluation of the Changes in Signal Intensity over Time Pre- and Post-administration of 0.2 mmol/kg Gd-DTPA.

PURPOSE: We are looking for a threshold value to discriminate between benign and malign breast lesions in MRI of female breast after administration of 0.2 mmol Gadolinum-DTPA/kg bw. MATERIALS AND METHODS: Double coil breast MRI (1.5 Tesla) were performed in 65 patients with an suspicious lesion for malignancy in an anteriorly examination. 57 patients could be evaluated in our study design. Histopathological 35 patients had an invasive carcinoma, 3 patients had an in-situ-carcinoma and in 27 patients benign changes were found. RESULTS: For different carcinoma diameters we found a different increase of signal intensity (SI): small carcinoma (< 10 mm) had an maximum increase of SI of 102 %, medium sized (10 to 20 mm) 222 % and carcinomas over 20 mm showed an increase of 271 %. We did not find a significant difference between SI in benign and malign lesions. The sensitivity was 94.6 % the specificity 65 %. CONCLUSION: A threshold value to distinguish between malign and benign in MRI could not be defined. With the double normal Gd-DTPA dose we do not have better specificity and sensitivity than for normal dose (0.1 mmol/kg bw) is described.

[Neoplasms of the temporomandibular joint (TMJ). Diagnosis, differential diagnosis and intervention]. / Neoplasien des Temporomandibulargelenks (TMG). Diagnostik, Differenzialdiagnostik und Intervention.

PURPOSE: To evaluate the effectiveness of diagnostic and interventional radiological techniques for neoplastic lesions of the temporomandibular joint (TMJ). MATERIAL AND METHODS: Modern diagnosis of the TMJ is based on the clinical use of conventional X-ray techniques, computed tomography (CT), magnetic resonance imaging (MRI) and interventional techniques like biopsies, vascular occlusion and ablation. RESULTS: Conventional X-ray still forms the basic diagnostic procedure applied in open and closed mouth position. CT improves the diagnostic information and serves as the standard diagnostical instrument for cartaliganeous or osseous neoplastic lesions. MRI evaluates soft tissue infiltration in multiplanar techniques and high spatial resolution. Interventional vascular and ablative techniques improve the treatment of neoplastic disorders. CONCLUSION: Radiological diagnostic procedures are essentials for the diagnosis and intervention of neoplastic lesions of the temporomandibular joint.

[Dynamic magnetic resonance tomography (MRI): a follow-up study after femur core decompression and instillation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in avascular femur head necrosis]. / Dynamische Magnetresonanztomographie (MRT): Verlaufsbeobchtung nach Femurkerndekompression und Auffüllung mit rekombinantem, humanem Bone morphogenetic Protein-2 (rhBMP-2) bei avaskulärer Femurkopfnekrose.

OBJECT: The aim of the study was to test the use of dynamic magnetic resonance imaging study with Gd-DTPA-application and the dynamic changes of signal intensity at patients with avascular femoral head necrosis after having installed rhBMP-2 and/or decompressed the core. MATERIAL AND METHODS: Six patients with avascular necrosis of the femoral head ARCO-stage I- or II-lesions were treated surgically by femoral head core decompression. Three of these patients were additionally treated with rhBMP-2-instillation. The progression or regression could be confirmed by T1- and T2-weighted spinecho-sequences (zero, four, ten, sixteen weeks and 24 months follow up). RESULTS: Corresponding ARCO-classification with partly more sensitive measurement of vitality signs in comparison to the optical x-ray classification. The objective, quantitative measurement of signal intensity post contrast medium reduces the influence of experience and level of education. The dynamic sequences results are reproducible. CONCLUSION: The dynamic magnetic resonance imaging study after Gd-DTPA-application and the dynamic changes of signal intensity after Gd-DTPA enhancement in the necrotic areas of the femoral head were the important subject of our study and it seems, that these sequencies and the ascertainment of signal intensity changes will be an efficient method for judgement of vitality, vascularisation and perfusion after therapeutical intervention. Combination of femoral head core decompression and rhBMP-2-instillation for the purpose of osseous regeneration seems to stabilize the affection.

A new protection/activation strategy for the synthesis of naturally occurring and non-natural alpha-N-alkylamino acids.

A new method for the preparation of N-methylamino acids and some of their derivatives starting from hexafluoroacetone protected amino acids is described. The new concept results in saving of steps compared to conventional protection/activation techniques. Protection and deprotection proceed without recemization.

Thoracic computed tomography of patients infected with the human immunodeficiency virus: relevance for the course of disease.

To determine the diagnostic accuracy and prognostic implications of thoracic computed tomography (CT) in patients with human immunodeficiency virus infection (HIV), CT scans of 154 HIV-infected patients (mean age, 41 years; range 23-65 years; 18 female) with suspicion of pulmonary disease were retrospectively reviewed for signs of disease by two investigators blinded to clinical data other than positive HIV serology. Abnormal CT features were correlated with CD4-T lymphocyte count, histologic or microbiologic diagnosis, and survival. Computed tomography detected features of pulmonary disease in 133 patients. A recent chest film was available in 96 patients, and it was normal in 16. In 17 of 99 patients (17%) with histologic or microbiologic correlation, pathologic CT features could be demonstrated, though histologic and microbiological studies were unrevealing. Median survival was 649 days. Confluent pulmonary infiltrates and bilateral masses on CT indicated advanced disease with a median survival of 115 days (n = 11, p = 0.0005) and 174 days (n = 15, p < 0.0001), respectively. The authors concluded that thoracic CT detects pulmonary lesions in an appreciable portion of HIV-infected patients in whom chest radiographs, microbiologic methods, or histology failed to establish a diagnosis, and that CT findings allow for an estimation of patient survival in acquired immunodeficiency syndrome.

Abdominal CT features and survival in acquired immunodeficiency.

PURPOSE: HIV-infected patients show a high incidence of abdominal disease. This investigation was made to determine whether abdominal CT provided prognostically relevant information in these patients. MATERIAL AND METHODS: Images from 533 abdominal CT examinations in 339 HIV-infected patients were retrospectively reviewed for signs of abdominal disease, and correlated with clinical data and survival rates. The Kaplan-Meier analysis and rank testing of survival, and proportional hazards regression were used to define prognostic clinical and imaging findings. RESULTS: Of the 339 patients, 278 (82%) showed abnormal abdominal findings on CT. Median survival was 29 months. Of the imaging findings, hepatic masses (n = 11), pathologically enlarged lymph nodes (n = 48), and ascites (n = 7) were associated with poor survival, giving a median survival of respectively 13 months, 15 months, and less than 1 month. These three features showed no association with CD4(+)-T-lymphocyte count or CDC category. Main determinants of survival were a low CD4(+)-T-lymphocyte count, and certain abnormal CT findings. Splenomegaly (n = 147), hepatomegaly (n = 144), and lymphadenopathy (n = 111) were the most common abdominal findings on CT but lacked prognostic relevance. CONCLUSION: Abdominal CT offered prognostic implications in HIV-infected patients and might serve in risk stratification in selected patients. CT features such as hepatic masses, grossly enlarged lymph nodes, or ascites indicate advanced immunosuppression.

[Initial nuclear magnetic resonance tomography results of the treatment course of avascular femur head necrosis after femoral core decompression]. / Erste kernspintomographische Ergebnisse des Therapieverlaufs bei avaskulärer Femurkopfnekrose nach Femurkerndekompression.

The vascular femoral head necrosis is a serious illness, especially when appearing in patients aged 30 to 50 years. Many etiologic factors cause a femoral head necrosis such as, for example, high-dose steroids, abuse of alcohol, defect of bone marrow and trauma of the hip. Often the X-ray photograph leads to the diagnosis in the second stage (ARCO 1992) or in the third stage, when the femoral head has begun to collapse. The stage IIc and III shows an evident enhancement in contrast media in MRI. Contrast enhancement is demonstrated by STIR, FATSAT, T1-weighted and dynamic screening sequence. The characteristics of the contrast media enhancement argue for an active concomitant process of destruction and regeneration. This stage has the best chances for a drug or a surgical therapy. The evaluation of the signal intensity by the dynamic screening sequence is considered as an objective contribution for the staging of the femoral head necrosis. This enables one to differentiate between the curable stage IIc and the stage III, showing the beginning of breakdown of the femoral head.

[Dynamic computerized tomography of the bone marrow of normal and pathologic vertebrae]. / Dynamische Computertomographie des Knochenmarks gesunder und pathologisch veränderter Wirbelkörper.

PURPOSE: The contrast medium dynamics of normal and abnormal bone marrow was examined by CT. MATERIAL AND METHOD: Standardised sections of lumbar vertebrae were obtained after intravenous injection of 80 ml Ultravist 370 and time-density curves of the marrow spaces were calculated in 38 patients. RESULTS: Time-density curves of patients with normal bone marrow differed significantly from those with proliferative bone marrow diseases in respect of maximal density and uptake at 120 and 240 seconds. Patients treated by radiation showed reduced uptake. CONCLUSION: Variations in the time-density curves between normal and abnormal bone marrow provided evidence of different perfusion and uptake of the contrast medium in the extracellular space of the bone marrow. Further investigation will be necessary to determine whether dynamic CT is able to document the effect of radiotherapy or chemotherapy on malignant bone marrow infiltration.

[The efficacy of lead shielding in patient dosage reduction in computed tomography]. / Effektivität der Bleiabdeckung zur Dosisreduktion beim Patienten in der Computertomographie.

PURPOSE: Investigation of the efficacy of lead apron, testis capsule and thyroid collar for dose reduction in uterus, ovaries, testes and thyroid gland in computed tomography examinations. METHODS: At an Alderson-Rando phantom dose of uterus, ovaries, testes and thyroid gland was measured with thermoluminescent dose meters. CT of the upper abdomen, the whole abdomen and the skull were simulated without and with lead shielding. As lead shielding, a lead apron was attached around the pelvis of the phantom in case of CT of the upper abdomen, a testis capsule was used in CT of the whole abdomen and a thyroid collar in CT of the skull. RESULTS: In CT of the upper abdomen the lead apron did not lead to any recognisable dose reduction in uterus and ovaries. In CT of the whole abdomen the testis capsule led to a dose reduction in testes of 95% (1.39 mSv) and in CT of the skull the thyroid collar to a dose reduction in thyroid gland of 23% (0.19 mSv). CONCLUSIONS: In abdominal CT examinations the testis capsule is an important instrument to reduce the dose of the testes whereas the lead apron is not appropriate for a dose reduction in the uterus and ovaries. In CT of the skull the thyroid collar can remarkably reduce the scattered radiation exposure of the thyroid gland and should be recommended.

[Computer graphics methods for 3-dimensional imaging of intrapulmonary space-occupying lesions of CT and MRI images]. / Computergraphische Methoden zur dreidimensionalen Darstellung intrapulmonaler Raumforderungen aus CT- und MR-Bildern.

AIM: To improve the pre-operative planning of interventional procedures in thorax surgery different methods of computer-graphical visualization of intrapulmonary lesions and adjacent anatomical structures based on CT and MR data were realized and compared to each other. DESIGN: In 21 patients with intrapulmonary lesions the image data was segmented by interactive and automatic algorithms and different reconstruction techniques were applied (maximum intensity projection; color-encoded and transparent surfaces; volume rendering). Based on these three-dimensional reconstructions, different views from arbitrary perspectives (including simulated endoscopic images) were generated and animated film sequences of the 3D scene were displayed with 30 frames/second. RESULTS: For all patients under review, a high-quality presentation of the relevant structures was obtained by use of the applied computer-graphical techniques. Even combinations of different visualization methods in one image can be generated with the software we developed. CONCLUSIONS: The various methods for image segmentation allow a fast and comfortable processing even of large data sets. The calculated values of tumor surface and volume can be used for quantitative studies and therapy control. The planning of surgical and interventional procedures can be supported by the simultaneous visualization of the intrathoracic lesion and the surrounding structures.

[3-dimensional post-myelographic CT reconstruction in diagnosis and therapy planning of spinal dysraphism]. / Dreidimensionale postmyelographische CT-Rekonstruktion in der Diagnostik und Therapieplanung spinaler Entwicklungsstörungen.

Dysrhaphia is often associated with severe osseous aberrations of the spine such as, for example scoliosis, hemivertebra, and synostosis. With the advanced possibilities of the post-processing of CT-data (segmentation, three-dimensional reconstruction), post-myelo-CT is an excellent method for the evaluation of osseous structures and the myelon in preoperative planning.

[clinical application of multiplanar and 3D reconstruction of spiral CT in diagnosis of acetabulum fractures]. / Klinischer Einsatz multiplanarer und 3D-Rekonstruktionen der Spiral-CT in der Diagnostik der Azetabulumfrakturen.

This review describes recent visualizations of computed tomography for the diagnosis of acetabular fractures. The techniques of conventional and helical-CT for the imaging of the acetabulum are compared. Furthermore, the different methods of multiplaner and three-dimensional reconstructions e.g. shaded surface display, maximum intensity projection, and volume rendering are presented. Figures of each method are demonstrated and the diagnostic potential of multiplanar and three-dimensional imaging for fractures of the pelvis is discussed.

[Theoretical principles and technical realization of high resolution nuclear magnetic resonance tomography with the example of a dedicated coil system]. / Theoretische Grundlagen und technische Realisation der hochauflösenden Kernspintomographie (KST) am Beispiel eines dedizierten Spulensystems.

The theory of high-resolution magnetic resonance imaging (MRI) and the physical properties of a dedicated coil system with its clinical application are reviewed. To evaluate the spatial resolution of the system, a phantom sample was depicted by a transverse T1-weighted sequence (time of repetition 500 ms, time of echo 25 ms, 256 x 256 matrix, 3 acquisitions, field of view 25 mm2). Relative signal intensity decrease was less using the 5-cm coil, as signal intensity field distribution depends on coil diameter. The phantom appeared as an attainable resolution of 100-microns pixel width using the 2.5-cm coil. For the 5-cm coil the pixel width was 200 microns, not accomplishing clear resolution of the phantom. Coil head choice depends on the anatomic depth of the target organ. Work-up of the skin and musculoskeletal lesions is the main indication for high-resolution MRI using surface coils.

[Technique and economics of first worldwide roentgen conference via public phone lines with the Medical Desktop-Conference and Integrated Services Digital Network]. / Technik und Okonomie der weltweit ersten Röntgenbesprechung über das öffentliche Fernsprechnetz mittels medizinischer Desktop-Konferenz und ISDN.

The introduction of the world's first Medical Desktop-Conference via public phone lines (ISDN-S2M) in spring 1994 for the weekly discussion of radiological findings with 25 orthopedic surgeons has proved the effectiveness of this system developed by the project BERMED. The use of standard hard- and software as well as ISDN are the most important factors to keep the system costs low. Technical advantages can be seen in the immediate, loss-free transmission of image and other patient-related data and in the integration of digital archives. Medical advantages are the 24-hour-availability of the radiologist and quality-control of the radiologists work. Practitioners and external hospitals can be tied closely to radiological service centers by using ISDNetwork.

[Diagnostic results of abdominal computerized tomography in HIV-infected patients]. / Diagnostische Ergebnisse der abdominellen Computertomographie bei HIV-infizierten Patienten.

The exact frequency of pathologic findings in abdominal computed tomograms of HIV-infected patients is not yet known. To analyse such findings, CT scans of 339 HIV-infected patients were reviewed. While over four fifths of patients displayed abnormal findings; hepatosplenomegaly, lymphadenopathy, pathologically enlarged lymph nodes, and bowel wall thickening were the most common signs of disease. Only for enlarged lymph nodes could a dependency on clinical stage of the infection be demonstrated. As a conclusion, abdominal computed tomography reveals pathologic findings in the vast majority of HIV-infected patients, almost independent of clinical stage. Specifically, CT provides well documented lymph node staging. There are practically no age-or sex-dependent disease patterns in abdominal CT scans.