[Central neurological complication of an interscalene plexus catheter]. / Zentralneurologische Komplikation einer interskalenären Plexuskatheteranlage.

A 78-year-old patient received an interscalene plexus catheter for perioperative pain therapy during implantation of an inverse shoulder prothesis. After stimulation-assisted puncture under sonographic control, 25 ml of local anesthetic (LA) were first administered and then the catheter was placed using the through the needle technique. Immediately after the administration of another 5 ml of local anesthetic via the inserted catheter, the patient showed symptoms of total spinal anesthesia, so that she had to be intubated and ventilated. The following computed tomographic diagnostics of the neck revealed an intrathecal misalignment of the plexus catheter, the tip of which was lying dorsal to the vertebral artery at the level of the 5/6 cervical vertebrae. The catheter could then be removed without any problems and there were no neurological sequelae. The use of ultrasound with clear identification of the nerve roots C5-C7 and the surrounding structures provides additional security when installing an intrascalene catheter. The spread of the LA should be traceable at all times using ultrasound and should otherwise be immediately terminated. Furthermore, a strict adherence to the needle position while inserting the catheter without manipulation of the needle depth is necessary. The first injection of the catheter has to be performed under controlled conditions, preferably connected to surveillance monitors with neurological monitoring of the awake patient and control of vital signs with direct access to the emergency equipment.

[Malignant neoplasms of the female pelvis]. / Tumoren des weiblichen Beckens.

Cervical, endometrial and ovarian carcinomas are the main malignant neoplasms of the female pelvis. For CT, a thin-slice venous phase with good bowel contrast is used. For MRI, an anti-peristaltic agent is necessary. Thin-slice T2- weighted TSE images with a high in-plane spatial resolution are particularly suitable for imaging the uterine wall; a parenteral contrast medium is absolutely necessary to demonstrate endometrial and ovarian carcinoma. In the guidelines, MRI is recommended only for cervical cancer FIGO 1b and higher stages; nevertheless, CT and MRI play an important role in preoperative diagnosis of these tumors. Lymph node staging is performed during surgery where possible. In patients with endometrial carcinoma, preoperative staging focuses on the infiltration depth in the myometrium. Preoperative diagnosis of ovarian cancer centers on any tumor spread in the abdomen, and diagnostic imaging methods are designed to provide the surgeon with information about compartments of a possible peritoneal carcinosis that are difficult to see. In patients with incidental findings of ovarian masses, CT and MRI can detect evidence of malignancy, although an exact differential diagnosis is not usually possible in this very heterogeneous group of ovarian tumors.

Dose and image quality of electron-beam CT compared with spiral CT.

RATIONALE AND OBJECTIVES: To examine dose and image quality of electron-beam CT (EBCT) with continuous volume scan versus spiral CT. METHODS: An EBCT scanner was compared with a spiral CT (SCT) scanner. Three phantoms were used to measure low-contrast resolution, high-contrast resolution, slice width, and dose. RESULTS: The EBCT scans showed 30% lower high-contrast resolution for most settings. The dose was comparable to that of spiral CT with 3 mm collimation and 76%/106% higher with EBCT for 1.5 mm/6 mm collimation. Low-contrast resolution was comparable to that of spiral CT using 3 mm collimation, slightly worse for 1.5 mm, and bad for 6 mm EBCT collimation (four times higher dose to reach comparable contrast-to-noise ratio). CONCLUSIONS: Significant restrictions were found using EBCT with continuous volume scan. The authors found that 3 mm collimation can yield acceptable high-contrast resolution and good low-contrast resolution compared with spiral CT. The use of 6 mm or 1.5 mm collimation needs to be restricted to selected cases.

Evaluation of breath-hold contrast-enhanced 3D magnetic resonance angiography technique for imaging visceral abdominal arteries and veins.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic value of breath-hold contrast-enhanced 3D magnetic resonance angiography (MRA) for assessment of the visceral abdominal arteries and veins in patients with suspected abdominal neoplasms. METHODS: Twenty-one patients underwent MR imaging on a 1.5 T unit using a body phased-array coil. MRA was performed with a 3D-FLASH sequence (TR 3.8 ms, TE 1.3 ms, flip angle 25 degrees, acquisition time 20 seconds), 8 to 12 seconds after an intravenous bolus injection of Gd-DTPA. The acquisition delay between the arterial and the portal venous phase was 12 seconds. The image quality and the degree of vascular involvement were evaluated using coronal source images and maximum intensity projection reconstructions. Diagnosis was confirmed by surgery/histology. RESULTS: Image quality was optimal in more than 85% of the patients (19/21 arterial phase and 17/21 portal venous phase). MRA correctly predicted vascular status in 20 of 21 patients (95%), with complete concordance between MRA results and surgical findings. In one patient with chronic pancreatitis, MRA demonstrated a false-positive finding that could not be confirmed surgically. CONCLUSIONS. Breath-hold contrast-enhanced 3D-MRA is a valuable technique for assessing visceral abdominal arteries and veins.

MR imaging of pancreatic lesions. Comparison of manganese-DPDP and gadolinium chelate.

RATIONALE AND OBJECTIVES: To compare manganese-DPDP-enhanced and gadolinium-DTPA-enhanced MR imaging in patients suspected of having pancreatic cancer. METHODS: Fifteen patients who underwent MR imaging for suspected pancreatic cancer and received gadolinium-DTPA took part in a clinical phase III trial in which the efficacy of manganese-DPDP for detection of pancreatic cancer was evaluated. T1-weighted gradient-echo (GRE) images with and without fat suppression were used. Signal-to-noise ratio and contrast-to-noise ratio were calculated before and after the administration of each contrast agent. Image quality was assessed using a four-step score; delineation of the normal pancreas was assessed by two readers in consensus. RESULTS: In terms of pancreatic signal-to-noise ratio, only gadolinium-DTPA-enhanced fat-suppressed and non-fat-suppressed GRE imaging showed a significant (P < 0.001) increase (72% and 61%, respectively). In the patients with a focal pancreatic lesion (n = 14), a significant increase in contrast-to-noise ratio was found only in manganese-DPDP-enhanced GRE imaging without (106%) and with (82%) fat saturation. Qualitative image analysis demonstrated a significant improvement of manganese-DPDP-enhanced fat-suppressed MR images in delineating the pancreatic parenchyma (P < 0.01) as well as pancreatic tumors (P < 0.01). CONCLUSIONS: T1-weighted manganese-DPDP-enhanced GRE imaging with fat saturation should be regarded as the most suitable combination for detecting a pancreatic lesion.

The contrast-detail behaviour of a photostimulable phosphor based computed radiography system.

Contrast-detail measurements were performed on a computed radiography imaging system as a function of detector entrance air kerma over the dose range from 0.743 microGy (0.085 mR) to 277 microGy (31.8 mR). A theoretical model of contrast-detail behaviour for a photostimulable phosphor computed radiography system has been derived, which is based on a modified version of the Rose theory of threshold detection. Included in the model are both system and x-ray quantum noise terms, as well as the response of the eye. The zero-frequency noise power of the computed film images was measured with a double-beam scanning microdensitometer. For a given detector dose, good agreement was found between the predicted and measured data when this measurement of system noise was included in the model. The contrast-detail results obtained for the computed radiography system were also compared with contrast-detail results for an image intensifier-TV based digital imaging system and a conventional film-screen system.

Idiopathic myelofibrosis with extramedullary hematopoiesis in the kidneys.

Extramedullary hematopoiesis is a common finding in idiopathic myelofibrosis and is usually found in liver and spleen. We report on a patient with biopsy-proven myeloid metaplasia and fibrosis of the renal parenchyma as a rare cause of chronic renal failure. The renal biopsy specimen showed numerous infiltrates of hematopoietic cells expressing growth factors like M-CSF, GM-CSF, IL-1beta and PDGF while TGF-beta was not elevated. These findings suggest that hematopoietic growth factors play a key role in the pathogenesis of this condition causing proliferating fibrosis and enlargement of the kidneys.

Radiation dose and image quality in spiral computed tomography: multicentre evaluation at six institutions.

The purpose of this study was to evaluate the correlation of radiation dose with image quality in spiral CT. Seven clinical protocols were measured in six different radiological departments provided with four different types of high specification spiral CT scanners. Central and surface absorbed doses were measured in acrylic. The practical CT dose index (PCTDI) was calculated for seven clinical examination protocols and one standardized protocol using identical parameters on four different spiral CT scanners with a dedicated ionization chamber inserted into PMMA phantoms. For low contrast measurements, a cylindrical three-dimensional (3D) phantom (different sized spheres of defined contrast) was used. Image noise was measured with a cylindrical water phantom and high contrast resolution with a Perspex hole phantom. Image quality phantoms were scanned using the parameters of the clinical protocols. Images were randomized, blinded and read by six radiologists (one from each institution). PCTDI values for four different scanners varied up to a factor between 1.5 (centre) and 2.2 (surface) for the standardized protocol. A greater degree of variation was observed for seven clinical examination protocols of the six radiological departments. For example, PCTDI varied up to a factor between 1.7 (cerebrum protocol) and 8.3 (abdomen paediatric protocol). Low contrast resolution correlates closely with dose. An improvement in detection from 8 mm to 4 mm sized spheres needs approximately a ten-fold increase in dose. Noise shows a moderate correlation with PCTDI. High contrast resolution of clinical protocols is independent of PCTDI within a certain range. Differences in modern CT scanner technology seem to be of less importance for radiation exposure than selection of protocol parameters in different radiological institutes. Future discussion on guidelines regarding optimal (patient adapted) tube current for clinical protocols is desirable.

Digital fluoroscopic radiology: evaluation of the clinical impact.

The use of digital image intensifier radiography (DIIR) for examinations in projection radiography is becoming more common. Fluoroscopic controlled contrast studies (barium- or iodine-based), particularly of the gastrointestinal tract, can be performed quickly and easily with a considerable decrease in radiation exposure. A wide dynamic range permits a constant high image quality with fewer incorrect exposures. The limited spatial resolution of large image intensifier input screens is the major drawback of DIIR. Digital image acquisition enables post-processing, digital storage and transfer of images, thus allowing an integration into PACS-systems. Imaging capabilities and clinical applications are described here.

[Digital image intensifier radiography--one year's experience with a Polytron system]. / Digitale Bildverstärker-Radiographie--einjährige Erfahrung mit einem Polytron-System.

Since January 1988, digital image intensifier radiography has been used in the Clinic in Mannheim for DSA examinations and also in place of conventional screen/film examinations. Measurements have shown that compared with 100 mm and film/screen formats, digital radiography has poorer spatial resolution, but improved contrast resolution. The most common use of digital radiography was for examinations of the gastrointestinal tract. Using the demonstration of the mucosal fine relief pattern as a criterion of image quality, digital image intensifier radiography was able to achieve this satisfactorily. Comparison with film/screen examinations showed no loss of diagnostic information. Advantages of image intensifier radiography are reduced radiation dose, the possibility of postprocessing and economy. On the basis of 399 examinations, digital image intensifier radiography is now firmly established as part of the daily routine of the Mannheim Clinic.

[Do the obstetrically relevant bony pelvic measurements change? A retrospective analysis of computed tomographic pelvic x-rays]. / Andern sich die geburtshilflich relevanten knöchernen Beckenmasse? Eine retrospektive Analyse computertomographischer Beckenaufnahmen.

The important dimensions of pelvimetry were evaluated from 467 CT studies of the pelvis by trigonometric deduction. The age of the women was between 18 and 88 years. In addition to the diameters, which are routinely used for pelvimetry, transverse and sagittal diameters, pelvic angles and areas of pelvic planes were calculated. On condition that the pelvic dimensions do not depend on age the parameters can be regarded as representative of sexual maturity. 5 parameters showed highly significant and 7 parameters showed significant differences between the age-classes 1901-1920 and 1950-1971. An increase of pelvic dimensions (1950-1971) was found at the planes of the pelvic inlet and outlet in contrast to the dimensions of the pelvic center. The results confirm the importance of the bispinous diameter for pelvimetry as well as the demand for a revision of the standard values of the first half of the century.

[Obstetric pelvimetry using digital image intensifier radiography]. / Geburtshilfliche Beckenvermessung mit der digitalen Bildverstärkerradiographie.

Obstetric pelvimetry can be performed by digital image intensifier radiography using very low exposure doses. Comparative measurements show a reduction of the entrance dose to 5% of conventional respectively 15% of high speed film-screen radiography. Phantom measurements have shown an accuracy of +/- 5 mm. In 30 patients the transverse diameter of the pelvic entrance, of the interspinous and of the intertuberous level as well as the sagittal diameter of the pelvic entrance and outlet were measured. Pelvimetry is indicated for the early recognition of certain risks if anamnestic (previous Caesarean section), clinical (eg. external pelvimetry) or fetometric features indicate the evidence of disproportion. As a radiological method the image intensifier radiography appears particularly recommendable in respect of its low exposure dose and the possibility of interactive measurements with subsequent documentation of the diameters and values.

[The value of digital imaging techniques in skeletal imaging]. / Die Wertigkeit digitaler Bildaufnahmeverfahren bei der Skelettdiagnostik.

The clinical value and the imaging characteristics of digital radiography systems (image intensifier (I.I.) radiography: Polytron/Siemens, storage phosphor radiography: PCR/Philipps) in skeletal imaging were compared with film-screen radiography and 100 mm technique. The influence of spatial and contrast resolution, entrance dose and detectability of lytic, osteoblastic and cortical lesions were studied as well as the images of 25 parallel examined patients. Only with the small image intensifier (diameter 14 cm) the quality of 100 mm technique and digital I.I. radiography was equivalent to storage phosphor and film-screen radiography. Storage phosphor radiography seems to be better qualified than I.I. radiography to replace conventional techniques in skeletal imaging.

[Value of dual-phase-helical CT in the preoperative diagnosis of pancreatic cancer--a prospective study]. / Wertigkeit der Doppelspiral-CT bei der präoperativen Diagnostik des Pankreaskarzinoms--eine prospektive Studie.

PURPOSE: A prospective study was performed to evaluate the accuracy of dual phase helical CT in suspected pancreatic cancer. METHODS: Within one year 136 patients underwent helical CT with arterial and portal venous scans after bolus tracking and NaCl bolus injection. Evidence of pancreatic cancer and assessment of resectability were recorded using a standardised protocol. Suspected benign disease was verified by follow-up examination and clinical data, suspected malignant disease was correlated with biopsy or surgery. RESULTS: For the detection of tumor the overall concordance was 92%, the sensitivity 98% and the specificity 70% (6 false positive, 1 false negative). Resectability was correctly assessed in 90% with a sensitivity of 92% and a specificity of 88% (4 false positive, 4 false negative). Vascular invasion was detected correctly in 91% (veins)-94% (arteries), lymph node invasion in 67% and liver metastasis in 94%. CONCLUSION: Dual phase helical CT is a very reliable tool in the assessment of resectability in pancreatic cancer.

[Value of high-resolution CT of the lungs in acute pulmonary symptoms of patients with HIV infections]. / Wertigkeit der HRCT der Lunge bei akuter pulmonaler Symptomatik HIV-Infizierter.

PURPOSE: The purpose of this study was to assess the clinical value of HRCT of the lung in patients with known HIV-infection and acute lung disease. In a prospective study a HRCT was performed in 31 patients infected with the HIV-1 virus, mainly stage C (CDC), who had acute pulmonary symptoms. Precondition for the HRCT examination was a normal or non-specific chest radiograph. A provoked sputum as well as bronchoscopy with bronchoalveolar lavage and/or transbronchial biopsy were performed concurrently. In 24 out of 31 cases a pathogenic organism was identified. 19 of these 24 patients showed abnormal HRCT findings. The most frequent pathogenic organism was Pneumocystis carinii (n = 12). 9 out of these 12 patients (75%) showed pathological HRCT findings consisting of ground-glass opacity. Specific patterns of attenuation could not be worked out except for Pneumocystis carinii infection. Compared to bronchoalveolar lavage, the diagnostic value of HRCT is inferior; it is however helpful in the early stage of disease, when the pathogenic organism has not yet been identified, HRCT may demonstrate parenchymal abnormalities in patients with normal radiographic findings. Compared to bronchoalveolar lavage and induced sputum, HRCT can provide conclusive results within a short time.

[Documentation of digital image information--video or laser imager?]. / Dokumentation digitaler Bildinformationen--Video- oder Laser-Imager?

The quality of hardcopies produced by a video- or laser imager was compared. Laser printing could be performed after analogue or digital data transmission, whereas the video imager allowed only analogue data transfer. Evaluation of CT-, MR-, DSA- and radiographic images showed no difference in diagnostic information between video and laser-produced hardcopies. For large formats (35 X 35 cm.), laser images produced by digital transmission were considerably superior to video signals and analogue transmission. There were advantages and disadvantages of both types of imaging, depending on the size of the matrix, the type of image produced, ease of use and capital cost.

[Thoracic radiographs with the AMBER system. A comparison of the diagnostic image quality of film-screen and storage-phosphor radiographs on the grid-partition stand and the AMBER system]. / Thoraxaufnahmen mit dem AMBER-System. Ein Vergleich der diagnostischen Bildgüte von Film-Folien- und Speicher-Folien-Aufnahmen am Rasterwandstativ und AMBER-System.

Since April 1990, chest radiographs in the Mannheim clinic have been performed with a slit technique (Kodak AMBER System). In this study, image quality from conventional film/screen combination and from storage phosphor radiography was compared with that from the AMBER system. Phantoms were used to measure spatial resolution and to determine the detectability of nodules. Image quality affecting various structures within the thorax was evaluated on 200 p.a. and 48 lateral radiographs by three radiologists from Mannheim and four from Berlin. In the retrocardiac, retrodiaphragmatic, mediastinal and peripheral portions the best image quality was obtained by film/screen with the AMBER system. Compared with conventional film/screen images, there was no improvement from the AMBER system within the lung parenchyma. The use of storage phosphor plates with the AMBER system did not lead to any further improvement in image quality.

[Magnetic resonance tomography as the basis for biomechanical analysis. The simulation of the birth process as an example of the expanded information potentials of segmental imaging procedures]. / Die Magnetresonanztomographie als Grundlage biomechanischer Analytik. Die Simulation des Geburtsvorganges als Beispiel für erweiterte Aussagemöglichkeiten segmentierender bildgebender Verfahren.

A method is presented that enables the use of (static) informations from magnetic resonance imaging (MRI) for (dynamic) biomechanical analysis. Using a specially developed software MRI pixel matrices are colour-coded and--according to the principle of same density--line data are created. After sectional attribution of the resulting polygons a three-dimensional mesh of so-called finite elements is created which can then be used in deformation analysis. This method is exemplified by a project dealing with the simulation of birth mechanics, which is finally aimed at validating the results from radiologic pelvimetry. First analyses show that even under foetal head moulding conditions, being considered as normal, such sensitive structures as the cerebellum, brain stem as well as the ventricles with the plexus chorioidei are to be found within the maximum isobars within a range of 104-140 N(10.6-14.3 kp).

[Development of a clinical-radiological CD-ROM database for focal lesions of the liver]. / Aufbau einer klinisch-radiologischen CD-ROM-Datenbank am beispiel fokaler Leberläsionen.

PURPOSE: The development of a CD-ROM database for continuous acquisition and archiving of interesting radiologic cases is described. As a pilot study radiologic images of focal lesions of the liver were collected. METHODS: The database runs on a PC (80486 DX2, 66 MHz, 16 MB RAM), which is connected to the clinic network, a high quality x-ray scanner and a CD-ROM writer. Radiologic images can be inserted into the database either by scanner or by image transfer via network. The database is designed using Access 2.0. Well documented cases were chosen retrospectively, manipulated and archived. RESULTS: 308 images of 12 focal lesions with a capacity of 802 MB were stored on CD-ROM. Per case a storage capacity of 40-75 MB is necessary for image raw material, 15-25 MB are necessary for the postprocessed data. Spatial resolution is 190 dpi (3000 pixel/40 cm). Clinical data, radiological diagnosis coded by modified ACR index and a compressed icon of the images are stored on PC, the image data are stored on CD-ROM. 2.5 hours per case are needed for the complete acquisition, manipulation and archiving procedure, but improved hardware configuration can reduce the time significantly. CONCLUSION: The described database allows continuous archiving of interesting radiologic cases on PC. ACR index is suited for a quick search of a specific combination of radiologic images and diagnosis from different modalities.

[Bolus tracking and NaCl bolus in biphasic spiral CT of the abdomen]. / Bolustriggerung und NaCl-Bolus bei der biphasischen Spiral-CT des Abdomens.

PURPOSE: To optimise injection parameters in helical CT of the abdomen with individual bolus tracking and subsequent NaCl bolus injection. To investigate the effect of bolus tracking on image quality in the abdomen. METHODS: Patients were randomised into three examination protocols and underwent biphasic helical CT (Hi-Speed Advantage, GE). The effect of NaCl bolus on duration of aortic enhancement was investigated. Contrast enhancement in parenchyma and vessels was examined. The influence of body mass index, injection flow and contrast material volume on enhancement was evaluated. RESULTS: Subsequent injection of NaCl provided significant extension of contrast enhancement in the aorta. Optimal image quality for pancreas and abdominal arteries was achieved in the arterial phase and for liver, spleen, kidneys and abdominal veins in the portal venous phase. Body mass index, injection flow and contrast material volume showed a significant influence on the time intervals resulting from bolus tracking. CONCLUSION: Individual bolus tracking with subsequent injection of 20 ml NaCl bolus optimises intravenous contrast application.