In vivo microscopic evaluation of the microvascular behavior of FITC-labeled macromolecular MR contrast agents in the hamster skinfold chamber.

RATIONALE AND OBJECTIVES: The extravasation properties of two macromolecular MR imaging contrast media (CM) in relation to structural differences of the terminal vascular bed were investigated to determine whether differentiation between normal (physiological) and tumor (pathological) tissue can be achieved by means of extravasation characteristics. METHODS: Gd-DTPA-polylysine (50 kD, CM1) and Gd-DOTA cascade polymer (Gadomer 17; 20 kD, CM2) were labeled with fluorescein isothiocyanate (FITC) to enable in vivo fluorescence microscopy of the microcirculation. After implantation of a dorsal skinfold chamber and 7 days (range, 6-8) after induction of an amelanotic melanoma (A-Mel-3), 14 male hamsters weighing 85 g (range, 70-95 g) received 200 micromol/kg of CM1 by intravenous injection into the jugular vein. CM2 was similarly investigated after an interval of 24 hours. Fluorescence microscopy was performed in areas of subcutaneous tissue, striated muscle, and tumor tissue. Microscopic images were registered by a charge-coupled-device video camera and transferred to a video system. Distribution intensities of CM were evaluated on a digitally based measurement system. A control investigation was performed with FITC-dextran (150 kD). RESULTS: Gd-DTPA-polylysine showed no extravasation into physiological tissue for the first 10 minutes after injection. After this period, however, the first signs of leakage became apparent. Gd-DOTA cascade polymer was extravasated after 5 minutes into the tumor-free tissue. In tumor capillaries, Gd-DTPA-polylysine could be detected in the extravasal space as well as in physiological tissue after 15 minutes. After injection of Gd-DOTA cascade polymer, direct leakage from tumor capillaries was observed, with a contrast maximum between tumor and surrounding tissue occurring 3 to 5 minutes after CM injection. Good delineation of tumor vascularization from striated muscle and subcutaneous tissue was achieved. CONCLUSIONS: The CM studied showed different microvascular permeation properties. Faster leakage of Gd-DOTA cascade polymer was observed in areas with neoplastic tumor vessels, whereas extravasation in physiological tissue was detected after a period of 5 minutes. Gd-DTPA-polylysine demonstrated nonspecific leakage at later time points.

Iodinated radiographic contrast media inhibit the capacitative calcium entry into smooth muscle cells of the swine renal artery.

RATIONALE AND OBJECTIVES: To investigate whether nonionic, iodinated, radiographic contrast media (RCM) could modulate calcium release from or calcium entry into smooth muscle cells of the swine renal artery. METHODS: Intracellular calcium concentrations of isolated myocytes loaded with the calcium-sensitive dye fluo-3 were analyzed using a fluorescence imaging system. Calcium signals were compared with isometric contractions of vascular segments in an organ bath. The effects of the triiodinated monomer iomeprol were compared with those of a mannitol solution. RESULTS: Stimulation of alpha-receptors by phenylephrine caused a biphasic calcium signal. Transient liberation of calcium from intracellular stores triggered the sustained entry of extracellular calcium (capacitative entry). Iomeprol and mannitol slightly inhibited the initial transient spike to the same extent. The calcium influx was reversibly inhibited by RCM by about 50%. Up to a concentration of 40 mmol/L, the inhibition induced by iomeprol was significantly higher than that induced by mannitol (P < 0.05-0.01). In isolated arterial segments, relaxation of the contraction phase depending on the calcium influx was significantly higher with the RCM than with mannitol (P < 0.01). CONCLUSIONS: Vasodilatation by CM is associated with a reduction in the capacitative entry of calcium. The mechanism of this effect is not clear, but it can be ruled out that it is mainly due to the high osmolarity of these compounds.

A study of dose reduction using digital luminescence radiography for lateral skull radiography.

For lateral skull radiography the minimum required radiation patient exposure to ensure adequate image quality was determined for digital luminescence radiography (DLR) in comparison with a screen-film system (speed class 200). Radiographs were produced with a grid technique on conventional X-ray equipment. A real prepared female head including a true fracture above the pars petrosa ossis temporalis was imaged. The tube current-time product (mAs), and thus the surface entrance dose, was varied systematically. Surface entrance dose was measured with TLD-100 rods. Image quality was judged by experienced radiologists according to the criteria: visual resolution, mean optical density, contrast and perceptibility of specific bone structures. Surface entrance dose was reduced from 0.46 to 0.20 mGy by application of DLR instead of speed class 200 screen-film system without loss of diagnostic information in clinical routine. This corresponds to a dose reduction potential of 57% showing a good agreement with the dose reduction potential of 52% obtained in a previous study using the Alderson head phantom.

Rupture of the spleen by penetration of pancreatic pseudocysts.

2 patients with known chronic recurrent pancreatitis and proven pancreatic pseudocysts in the tail of the pancreas developed a pseudocystic invasion of the spleen followed by tryptic erosion of it. This complication, previously seldom reported, occurred twice in one year, the diagnosis being achieved by CT.

Biliary drainage by teflon endoprosthesis in obstructive jaundice--experiences in 69 patients treated by PTCD or ERCD.

In 69 patients with extrahepatic biliary obstruction a specially designed teflon tube, the endoprosthesis, was inserted across the ductal stenosis either by percutaneous or by endoscopic route to reduce jaundice. After gaining experience our success rate of stent placement was more than 90%. Compared with catheter drainage the endoprosthesis worked faster and more efficiently, while in palliative treatment the quality of life of the patient improved and secondary cholangitis was prevented. The rate of significant long-term stent obstruction can be tolerated in view of the expected life span of four months as average in our material.

Inflammatory pseudotumor of the liver in a patient with congenital granulocytopenia and HCV infection.

Inflammatory pseudotumor (IPT) of the liver is a rare pathologic lesion. Although IPTs within the liver shows spontaneous regression, these lesions are frequently misdiagnosed as malignant on the basis of the clinical manifestation and the results of diagnostic imaging. With special regard to magnetic resonance imaging (MRI), differential diagnosis such as hepatocellular or cholangiocellular carcinoma (HCC/CCC) as well as regenerative liver lesions are discussed in a case of IPT with concomitant hepatitis C virus (HCV) infection and congenital granulocytopenia.

[Intravenous arteriography with xerography: a non-invasive method for the demonstration of peripheral vessels (author's transl)]. / Die intravenöse Arteriographie im Xeroxbild: Eine nichtinvasive Methode zur Darstellung peripherer Gefässe.

Acceptable arteriograms of the extremities can be obtained by rapid manual injection of contrast into a cubital vein, using a xeroradiographic technique. The indications and value of the method have been demonstrated in 62 examinations. The new technique constitutes a non-invasive arteriographic method suitable for demonstrating limited vascular lesions in the extremities.

[A new method for localising non-palpable lesions of the female breast (author's transl)]. / Eine neue Methode zur Lokalisierung nicht tastbarer Läsionen der weiblichen Brust

A new method for the localisation of non-palpable lesions of the female breast is described. It is uncomplicated, very accurate and simple, and requires a single puncture only. It enables a cytological diagnosis to be made, as well as preoperative marking of suspicious areas.

[Diagnosis of postpartum complications using CT and MRT]. / Diagnose postpartaler Komplikationen mittels CT und MRT.

Severe puerperal infections, iliacal and ovarian vein thrombosis are post-partum complications which are potentially life-threatening. They require prompt medical treatment. CT and MR enable diagnosis by noninvasive methods.

[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.

[Gallbladder perforation on the computed tomogram]. / Gallenblasenperforation im Computertomogramm.

Seven cases of perforated gallbladder disclosed by computed tomography are reported. In all cases the symptoms were obvious. As clinical signs and ultrasound do not always give reliable results, computer tomography plays an important rôle in the diagnosis of gallbladder perforation.

[Pancreatic carcinoma on endoscopic retrograde pancreatico-cholangiogram (author's transl)]. / Das Pankreaskarzinom im endoskopischen retrograden Pankreatiko-Cholangiogramm

The pancreaticographic appearances of carcinoma of the pancreas have been divided into two types: 1. Canalicular carcinoma arising from the duct system. If arising from the main pancreatic duct, it occludes this, or causes displacement or deformity of its branches in the immediate neighbourhood. If arising from branches, it causes cystic ectasia of the minor ducts; these appear fragmented and deformed while there is stenosis and displacement of the main duct. Simultaneous origin from the main and smaller ducts, as in the Gallert carcinoma, causes extreme lacunar ectasia of the minor ducts and occlusion of the main duct. 2. Carcinoma arising from the acinar epithelium. This causes primarily displacement and the secondarily stenosis of the main duct. Accuracy of ERCP is satisfactory. It is limited by technical failure or difficulties due to the pathology preventing demonstration of the pancreatic duct. It is increased by cytological examination of aspirated pancreatic secretion. Difficulties in the differential diagnosis from chronic pancreatitis can be overcome. The possibility of an early diagnosis of the carcinoma presented by this method loses some of its impact because the patients are seen at a late stage and because of the lack of early symptoms of this disease.

[Experiences with the endovascular embolization therapy of aneurysms of the splanchnic arteries--a report on 13 cases]. / Erfahrungen mit der endovaskulären Embolisationstherapie von Aneurysmata der Splanchnikusarterien--Bericht über 13 Fälle.

PURPOSE: The authors report on their experience in endovascular embolization therapy in 13 cases with splanchnic artery aneurysms or pseudoaneurysms. PATIENTS AND METHODS: Three patients suffered from true aneurysms, ten patients presented pseudoaneurysms of different origin. Eight patients were transferred to our department for life-threatening intestinal bleeding. Five patients showed transpapillary bleeding, four of whom presented with haemobilia and one patient had intermittent bleeding into the pancreatic duct due to a true aneurysm of the splenic artery. Embolization was performed using a coaxial microcatheter coil delivery system. In 4 patients the aneurysm-bearing vessel was temporarily blocked during the intervention. RESULTS: In 11 patients definite occlusion of the aneurysm was obtained without surgical intervention. In one patient, suffering from a splenic aneurysm, we observed a partial inadvertent embolisation of the spleen which did not require further treatment. In one case, rupture of an hepatic aneurysm during embolization occurred. One patient with pseudoaneurysm due to displacement of a port catheter showed severe rebleeding one day after embolisation. CONCLUSION: Transcatheter embolization is an effective method for treatment of aneurysms of the splanchnic arteries. To avoid life-threatening bleeding due to rupture of the aneurysm, the feeding vessel should be temporarily blocked during embolization therapy.

[Comparison of radiation exposure of patients caused by selected interventional and angiography procedures--initial results]. / Vergleich der Strahlenexposition von Patienten bei ausgewählten interventionellen und angiographischen Massnahmen--erste Ergebnisse.

PURPOSE: To determine and judge patient doses caused by selected interventional and angiographic procedures using the "Multiskip" digital C-arm unit. MATERIALS AND METHODS: The dose-area product and the fluoroscopic time were measured for 71 percutaneous transluminal angioplasties (PTA), 33 PTA with stent implantation, and 37 embolizations; in addition, they were also measured for 285 digital subtraction angiographies (DSA). In the case of 13 PTA, 10 embolizations, and 33 DSA the number of radiographs was determined, and the dose-area product was divided into two parts, fluoroscopy and radiography, applying a computer programme. RESULTS: The median values of the dose-area product and the fluoroscopic time amounted to 36 Gy cm2 and 11.5 min for PTA, 131 Gy cm2 and 14.4 min for PTA with stent implantation, 197 Gy cm2 and 24.5 min for embolisation as well as 87 Gy cm2 and 3.7 min for DSA. For the relation between dose-area products caused by fluoroscopy and radiography and the number of radiographs, median values of 0.67 and 70 for PTA, 0.58 and 153 for embolisation as well as 1.35 and 135 for DSA were determined. CONCLUSIONS: To reduce the relatively high patient doses the modification of the C-arm unit is aspired to realize pulsed fluoroscopy and automatic filter selection. Also experimental investigations will be done related to additional filtration and reduction of the image intensifier input dose rate and dose per frame, respectively. Then, the effect of dose reduction caused by these measures will be confirmed in a comparable patient study.

[Reduction of the radiation exposure of patients caused by selected interventional and angiographic procedures]. / Reduzierung der Strahlenexposition von Patienten bei ausgewählten interventionellen und angiographischen Massnahmen.

PURPOSE: To reduce patient doses caused by selected interventional and angiographic procedures using the digital C-arm unit "Multiskop". MATERIALS AND METHODS: After a patient study done previously, physical measurements with test phantoms were carried out, and physical-technical parameters such as distance between focus and image intensifier, additional filtration, and radiation dose per image were optimised. Then, the dose-area product (DAP) and the fluoroscopic time were measured for 130 percutaneous transluminal angioplasties (PTA), 40 PTA with stent implantation, 61 embolisations, and 302 digital subtraction angiographies (DSA). In the case of 16 PTA, 9 embolisations, and 38 DSA the number of radiographs was determined, and the DAP was divided into two parts, fluoroscopy and radiography. The measuring values were compared with data of the patient study done previously. RESULTS: The median values of the DAP and the fluoroscopic time amounted to 25 Gy cm2 and 9.7 min for PTA, 97 Gy cm2 and 8.5 min for PTA with stent implantation, 88 Gy cm2 and 17.2 min for embolisation as well as 54 Gy cm2 and 2.8 min for DSA. For the relation between DAP caused by fluoroscopy and radiography, and the number of radiographs, median values of 0.76 and 63 for PTA, 0.81 and 123 for embolisation as well as 1.85 and 134 for DSA were determined. In comparison to the patient study done previously the median values of the DAP were reduced by 31% for PTA, 26% for PTA with stent implantation, 55% for embolisation, and 38% for DSA. CONCLUSIONS: The comparison between the patient studies done previously and recently indicates the great potential of dose reduction for interventional and angiographic procedures. Although the X-ray equipment is ten years old the patient dose can be reduced by organizational and physical-technical modifications to such an extent that preliminary national reference dose values will not be exceeded. For further significant dose reductions while maintaining adequate image quality it will be necessary to purchase a modern X-ray equipment with pulsed fluoroscopy and automatic filter selection.

[MRI in testicular diagnosis: differentiation of seminoma, teratoma and inflammation using a statistical score]. / MRT in der Hodendiagnostik-Differenzierung von Seminomen, Teratomen und Entzündungen mit Hilfe eines statistischen Bewertungsmassstabs (Score).

PURPOSE: To differentiate scrotal pathology via MRI by means of a statistical score. METHODS: Between 1989 and 1995 MR images of 105 patients with scrotal pathology were rated retrospectively. In 69 cases linear discriminant analysis was used to differentiate seminoma, teratoma and inflammation. Six MRI attributes were found to be necessary and were weighted with a factor according to their importance. These factors were used to build a score. RESULTS: Criteria found to be important contained the distribution of the variate extensions of elements inside the pathological area and their maximal and minimal signal intensities. Furthermore, the contrast pattern of the pathological area and the visibility of healthy tissue in the pathological testicle was of importance. Seminoma was found to be homogeneous and well demarcated against healthy tissue. Teratoma was also well defined but characterised by inhomogeneous distribution of signal intensities. Inflammation showed diffuse signal increase of the pathological testicle, especially in T1-sequences. Using the score differentiation between tumors and inflammation succeeded in 94.2% between seminoma and teratoma in 89.7%. CONCLUSIONS: Compared to other studies using visual MR image analysis differentiation of scrotal diseases was improved by using a statistical score.

[Proton spin tomography of the orbit in post-traumatic motility disorders]. / Kernspintomographie der Orbitae bei posttraumatischen Motilitätsstörungen.

AIM: To analyse the value of MRI for the assessment of posttraumatic disturbances of eye motility. MATERIAL AND METHODS: We analysed retrospectively the results of 38 MR examinations of the orbit in 31 patients with posttraumatic motility impairment with preserved visus. 18 patients underwent MRI preoperatively. From this group 5 patients were additionally examined postoperatively. Another 5 patients who had not been examined prior to surgery were controlled postoperatively. Hence, a total of 10 patients with persisting disturbances was examined postoperatively. 8 patients who underwent MRI were not treated by surgery because of only minor disturbances. In all patients conventional radiography of the orbit was performed prior to MRI. Additional CT imaging was carried out in 12 patients. RESULTS: In 18 patients examined preoperatively we found displacement of orbital fat tissue, displacement and entrapment of orbital muscles, swelling of muscles and oedema in retrobulbar fat tissue. 10 patients from the postoperative group exhibited remaining prolapsed fat tissue, oedema in fat tissue and/or swelling of muscles. 8 patients had only small soft tissue changes which did not require surgery. CONCLUSION: Since it can image soft tissue precisely, MRI provides the decisive information in the assessment of motility impairment of the eye. In case of isolated orbital fracture with motility impairment, CT is not absolutely necessary for surgical therapy.

[The diagnosis of bone marrow lesions in the MR tomogram in children with diseases of the hematopoietic system with special reference to post-therapy changes]. / Zur Diagnostik von Knochenmarkläsionen im MR-Tomogramm bei Kindern mit Erkrankungen des hämatopoetischen Systems unter besonderer Berücksichtigung der posttherapeutischen Veränderungen.

119 MR-examinations of both tibiae, knees and the lower part of both femur were performed in 41 children suffering from bone marrow disease (27 ALL, 4 AML, 3 NHL, 1 agranulocytosis, 6 anaemia). T1- and T2-spin-echo sequences and a T2-gradient-echo sequence were used. Bone marrow changes in leukaemia were diffuse before therapy and patchy after therapy. Due to their different signal in T2-weighted images, differentiation of the post-therapeutic patchy findings into infiltrations, fibrosis, necrosis and siderosis seems to be possible. In future, MRI will be the method of choice for screening and controlling bone marrow disease if the examination time is shortened by using only a T1-spin-echo sequence and a T2-gradient-echo sequence.

[Radiation exposure in abdominal radiography with digital luminescence radiography and conventional screen-film system: an experimental animal study]. / Die Strahlenexposition bei der Abdomen-Ubersichtsaufnahme mit digitaler Lumineszenzradiographie und konventionellem Film-Folien-System--eine tierexperimentelle Untersuchung.

PURPOSE: To determine and compare the minimum required radiation exposure for a.-p. abdominal radiographs with digital luminescence radiography (DLR) and a screen-film system (SFS) providing adequate image quality in clinical routine. MATERIAL AND METHOD: Abdominal radiographs a.-p. of a pig were produced with DLR and SFS systematically varying the tube current-time product. The image quality was assessed by eight experienced radiologists according to the criteria of visual resolution, mean optical density, perceptibility of the lateral edge of the psoas, the caudal edge of the liver, bone structures and intestinal wall. RESULTS: The image quality of the digital radiographs was better for each criterion except visual resolution if the same current-time product was used for both techniques. From the minimum tube current-time products providing an adequate image quality it follows that a dose reduction of 57% can be achieved by applying DLR instead of speed class 200 SFS. CONCLUSION: The recently published guide-lines for quality assurance in x-ray diagnostics issued by the German Federal Board of Physicians recommend using speed class 400 SFS. Since in that case an approximately halved radiation dose is necessary, dose reduction is hardly to be expected with DLR.

[Percutaneous embolization therapy in severe cervicofacial hemorrhages]. / Perkutane Embolisationstherapie bei schweren zervikofazialen Blutungen.

PURPOSE: To analyse the use of transcatheter embolisation. MATERIAL AND METHODS: We report on 43 patients treated by transcatheter embolisation for head and neck haemorrhage from 1987 to 1995. There were 13 patients with idiopathic intractable epistaxis, 6 with iatrogenic and three with traumatic bleeding, 7 patients with bleeding from vascular malformations, 12 patients with haemorrhage from tumours, one ruptured aneurysm of the inferior thyroid artery and one patient bleeding from a retrolingual dystrophic goitre. RESULTS: In 11/13 patients with idiopathic epistaxis, this could be stopped. In 8/9 of the traumatic and iatrogenic bleedings the haemorrhage was treated by embolisation alone. In two cases additional elective surgical interventions were necessary. In 6/7 patients with vascular malformations embolisation resulted in long-lasting periods free from bleeding. Palliative embolisation in bleeding tumours resulted in haemostasis in 10/12 patients. Bleeding was definitely stopped in a patient with aneurysm of the inferior thyroidal artery as well as in a patient with bleeding from a dystrophic goitre. We observed a total of three complications, two transitory neurological disturbances and one permanent amaurosis. CONCLUSION: Transcatheter embolisation is an effective tool in the treatment of life-threatening head and neck bleedings.