[Effects of high-strip density anti-scatter grid on image quality and radiation dose]. / Einfluss eines Viellinienrasters auf Bildqualität und Strahlenexposition.

PURPOSE: Using a new type of a stationary high strip density grid (13/75) for plain films of the abdomen, the effect was evaluated with regard to quality and patient dose in comparison with an established moving radiographic grid (12/40). METHODS: The high strip density grid (13/75) was compared with a 12/40 grid using test objects and 100 patients per each grid type for plain films of the abdomen. The examinations were carried out via the screen-film system, speed class (SC) 400. Patients' weight, age and dose measurements were recorded. The image quality was evaluated via a multi-reader study using delineation of anatomical structures and a rating scale (score 1-5 or 1-3). RESULTS: Both measurements with test objects and patients abdominal plain films showed a decrease in radiation dose of 17% using the 13/75 grid, and 24%, respectively. The delineation of 4 out of 7 anatomical structures was slightly reduced with the new high strip density grid (maximum score reduction: 0.4), the image contrast, as well as the radiologists' subjective rating. CONCLUSION: Apart from an acceptable loss in image quality compared with the 12/40 grid, the new high strip density grid (13/ 75) enables a clear reduction in radiation dose.

[Emergency decompression of a mechanical colonic ileus before elective surgery: first clinical results of fluoroscopic stent placement]. / Notfallmässige Entlastung des mechanischen Kolonileus vor der frühelektiven Operation: Erste Ergebnisse der durchleuchtungsgesteuerten Stentapplikation.

PURPOSE: Evaluation of fluoroscopic stent placement as an emergency therapeutical approach for treatment of acute large bowel obstruction due to colorectal neoplasm. METHODS AND MATERIAL: From January to December 1996 in 11 patients suffering from colorectal stenosis due to known or supposed malignancy the indication for the fluoroscopic placement of self-expanding metal stents was established. All patients showed clinical and radiological signs of an acute mechanical large bowel obstruction. Elective single-stage surgery was planned if the decompression had been carried out successfully. RESULTS: Stent placement was successful in 8 cases. Functional success in respect of resolving the acute large bowel obstruction was seen in 7 out of 11 patients. Elective surgery was possible in all 7 cases creating a primary end-to-end anastomosis without major complications during the perioperative period. CONCLUSION: Fluoroscopic placement of self-expanding metal stents in malignant colorectal stenosis is a promising method to avoid emergency surgery.

[Ileus in colorectal carcinoma. Preoperative implantation of self-expanding metal stents and early elective surgery as an alternative to emergency surgery]. / Ileus beim colorectalen Carcinom. Präoperative Implantation eines Metallgitterstents und frühelektive Operation als Alternative zur notfallmässigen Operation.

INTRODUCTION: The objective of this study was to evaluate preoperative decompression with self-expanding metallic stents in patients with acute bowel obstruction due to colorectal carcinoma. METHODS: In 28 patients, admitted to our clinic between January 1996 and May 1999 with suspicion of acute colonic obstruction caused by a colorectal carcinoma, we attempted to insert under fluoroscopic control a self-expanding metallic stent in the stenosis. After successful relief of obstruction, an elective one-stage surgical procedure followed. RESULTS: The stent application was technically successful in 21 patients. In 19 patients symptom relief was reached within 2 days. One of these patients died perioperatively and two patients developed an anastomotic leakage. In eight of the other nine patients, in whom decompression was not possible, an emergency surgical procedure was performed; four of these patients died perioperatively. In only one of the five patients who survived, could a surgical procedure without an enterostoma be performed. CONCLUSION: In cases of acute malignant colorectal obstruction, preoperative stent application under fluoroscopic control is a reliable method to allow single-stage surgical resection without requiring a protective enterostoma.

Clinical evaluation of a new stationary high strip density antiscatter grid in comparison with a conventional moving grid: influence on image quality and patient radiation dose.

This study aimed to evaluate a new stationary 13/75 antiscatter grid in comparison with a moving 12/40 grid with regard to its influence on image quality and patient radiation dose. One hundred consecutive patients had plain films of the abdomen using a moving 12/40 grid and another 100 patients were examined with a stationary 13/75 grid (tube voltage 73 kV, film size 35 cm x 43 cm, film-screen system speed class 400). As an intraindividual comparison, radiographs of the abdomen with a film size of 18 cm x 43 cm were taken of 27 patients using both grid types for every patient. Patients' weight and dose-area product were recorded. Image quality was evaluated by a multireader study using standardized questionnaires and three- or five-level grading systems. Results showed that use of the 13/75 grid accords with the ALARA principle: measurement of the dose-area product demonstrated a dose saving of 24% for a film size of 35 cm x 43 cm and a saving of 34% for a film size of 18 cm x 43 cm without calling into question the diagnostic image quality. The mean scores of the 12/40 grid were lower for three out of six normal anatomic structures (P<0.05) among the 200 patients, indicating a loss of image quality with the 13/75 grid. Assessment of the intraindividual trial revealed reduced detectability of three out of four anatomical details when the 13/75 grid was employed. At the cost of a minor loss of image quality in comparison with the 12/40 grid, the new stationary grid provides a clear reduction of radiation dose under clinical circumstances.

Power Doppler sonography with and without echo-enhancing contrast agent and contrast-enhanced MRI for the evaluation of rheumatoid arthritis of the shoulder joint: differentiation between synovitis and joint effusion.

OBJECTIVE: To evaluate patients with clinically active rheumatoid arthritis (RA) of the shoulder for joint effusion and synovitis using conventional sonography, power Doppler (PD) sonography with and without echo-enhancing contrast agent, and contrast-enhanced MRI. DESIGN AND PATIENTS: Twenty-four patients (mean age 64 years) with known RA had one symptomatic shoulder evaluated by conventional gray-scale sonography and PD sonography before and after intravenous administration of the echo-enhancing contrast agent Levovist (300 mg/ml, 2.5 g). The degree and extent of the altered echo pattern in the subacromial bursa, axillary recess and glenohumeral joint seen by conventional gray-scale sonography and the intensity of vascular signals of PD sonography were compared with the findings of MRI obtained with T2-weighted turbo spin-echo sequences and contrast-enhanced T1-weighted fat-saturated spin-echo sequences. MRI was evaluated by two readers in consensus without knowledge of the sonographic findings. RESULTS: MRI, which was used as the reference examination, detected joint effusion in 71% (17/24) and synovitis in 92% (22/24) of the patients. Conventional sonography revealed an abnormal articular echo pattern in 96% (23/24) of the patients, especially in the axillary recess and subacromial bursa, but failed to attribute the altered echo pattern to either fluid or specific synovitis. PD sonography allowed a specific diagnosis of synovitis in 33% (8 patients), which increased to 50% (12 patients) after administration of an echo-enhancing contrast agent. In 42% (10/24) of the patients, the findings of synovitis demonstrated by MRI corresponded to an altered echo pattern by conventional sonography, but vascular signals were absent by PD sonography with or without echo-enhancing contrast agent. CONCLUSIONS: Using MRI as the "gold standard," PD sonography with and without echo-enhancing contrast agent cannot reliably identify synovitis or distinguish synovial inflammation from effusion in the shoulder joint.

In vivo laser-induced interstitial thermotherapy of pig liver with a temperature-controlled diode laser and MRI correlation.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of a new temperature-controlled Diode laser to generate in vivo tissue coagulations with laser-induced interstitial thermotherapy (LITT) in pig liver and MRI-correlation of these necroses. STUDY DESIGN/MATERIALS AND METHODS: Each of four animal subjects received eight treatments at four different constant temperatures (70, 80, 90, and 100 degrees C) and at two out of three different intervals (3, 6, 9 minutes), resulting in a total of 32 lesions. After sacrificing, the liver was examined in an open MRI (0.35T). Tissue necrosis was measured macroscopically and compared with the size measured by MRI. RESULTS: The size of the necrosis was energy dependent with the largest extent at 100 degrees C at 9 minutes (2.1 cm). The correlation between macroscopic lesion size and MRI findings was significant (P > 0.036). Histological workup excluded carbonization in every case. CONCLUSIONS: LITT carried out with the Diode laser provides reproducible necroses of pig liver in vivo. MR-imaging results compared favorably with those obtained by pathologic specimens.