MRI of the pharynx and treatment efficacy of a mandibular advancement device in obstructive sleep apnoea syndrome.

In obstructive sleep apnoea syndrome (OSAS), prosthetic mandibular advancement devices (MAD) seem to be a promising treatment alternative to conventional continuous positive airway pressure therapy. Unfortunately, while they are effective in some patients, they are ineffective in others or may even worsen OSAS. At present, it is not known whether predictors can be defined which allow for estimation of the potential effect of oral appliances on the severity of OSAS. Clinical and polysomnographical efficacy of a MAD was evaluated in 15 patients with OSAS. In addition, ultrafast magnetic resonance imaging (MRI) of the pharynx was performed in 13 of these patients at rest during transnasal shallow respiration and during performance of the Muller manoeuvre, both with and without the MAD, and the site of closure was determined. The MAD reduced the mean apnoea/hypopnoea index (AHI) from 19.8+/-14.5 to 7.2+/-7.4 x h(-1). Seven subjects (53.8%) had at least a 50% reduction in AHI to a value <10 x h(-1) with the MAD, whereas the MAD was ineffective in six patients. Five of the seven treatment responders had no significant pharyngeal obstruction during the manoeuvre with the device, while all of them had pharyngeal obstruction when not equipped with the device. Four of the six patients with treatment failure had a single velopharyngeal obstruction and two a combined obstruction of the velo- and glossopharynx during the Muller manoeuvre while wearing the device. The results of this study suggest that airway patency during the Muller manoeuvre while wearing a mandibular advancement device may be predictive of the success of obstructive sleep apnoea syndrome treatment with a mandibular advancement device.

Stereoscopic 3D CT vs standard 3D CT in the classification of acetabular fractures: an experimental study.

The accuracy of stereoscopic and standard three-dimensional (3D) CT in the classification of acetabular fractures was compared. A receiver operating characteristic (ROC) analysis was performed by two radiologists and two surgeons blinded to the presence of acetabular fractures in an animal model (a total of 62 porcine hips, 40 with artificial acetabular fractures). Classification of acetabular fractures was adopted from the literature. Interpretation was performed on a workstation using two specific volume rendering algorithms; unshaded and shaded bone. The ROC analysis did not demonstrate any benefit in stereoscopic 3D CT compared with standard 3D CT.

Successful treatment of intimal hyperplasia in renal arteries by endovascular brachytherapy.

PURPOSE: The present study shows the possibility of preventing restenosis of renal arteries by endovascular brachytherapy. METHODS AND MATERIALS: We present a patient suffering from rapid restenosis of both renal arteries with decreasing renal function. Percutaneous transluminal angioplasty (PTA) and stent implantation were unable to stop hypertension and to stabilize renal function. Both renal arteries and the right pole artery were treated by endovascular brachytherapy in one session. RESULTS: Six months after intervention, intraarterial digital subtraction angiography (DSA) showed no evidence of recurrence, and the blood pressure remained normal without medical treatment. CONCLUSION: Endovascular brachytherapy can help to prevent restenosis in renal arteries. It is possible to treat both renal arteries and one pole artery in one session without any disadvantage.

First experiences in CT-guided percutaneous transhepatic biliary decompression by means of real-time CT fluoroscopy.

BACKGROUND: Computed tomographic fluoroscopy (CTF), also called real-time CT, is increasingly used in interventional radiology but has not yet been recommended to guide percutaneous transhepatic biliary decompression (PTBD). We report our early clinical experiences with CTF-guided PTBD. METHODS: Sixteen consecutive patients underwent PTBD under CTF guidance because of obstructive jaundice caused by malignant tumor (11 cases of carcinoma of the bile duct, four cases of pancreatic cancer, and one case of metastasis). CTF-guided PTBD was performed on a helical CT scanner and a surgical C arm. Main target parameters were the success and complication rates, the number of necessary punctures, the time needed for successful puncture of a suitable bile duct, and the patients' radiation exposure. RESULTS: CTF-guided punctures of the bile duct for PTBD were successful on the first trial in 10 cases; in six patients, two hits were necessary. The time needed to hit a suitable bile duct was 6-21 s (median = 13 s). Therefore, the radiation exposure (skin) was 27-94.5 mSv. The additional implantation and stenting of the bile duct by means of the surgical C arm was uneventful in 15 cases. In one case, only external drainage could be achieved. Complications did not occur. CONCLUSION: CTF enables good visualization of the most suitable duct for puncture. Therefore, subsequent recanalization seems to be easier than other methods.

A comparative study of CT fluoroscopy combined with fluoroscopy versus fluoroscopy alone for percutaneous transhepatic biliary drainage.

PURPOSE: We compared CT fluoroscopy (CTF) for the initial puncture of bile ducts with conventional fluoroscopic guidance in patients with malignant jaundice in whom percutaneous transhepatic biliary drainage (PTBD) was planned. METHODS: Forty consecutive patients were randomized to two study groups: group A underwent PTBD under CTF and fluoroscopic guidance, group B underwent PTBD under fluoroscopic guidance alone. CTF-guided PTBD was performed using a combination of a helical CT scanner of the latest generation and a mobile C-arm; conventional PTBD was performed under fluoroscopic guidance in the angiographic unit. End points of the study were the success (a puncture that enabled safe placement of a guidewire in a suitable bile duct) and the complication rate (hemobilia, bile fistula, biliary peritonitis), the number of punctures required, the time needed for successful puncture of a suitable bile duct, and the patient's radiation exposure. RESULTS: CTF-guided puncture of peripheral bile ducts suitable for PTBD was successful at the first attempt in 16 cases, under conventional fluoroscopic guidance, in only two cases. We found a significantly different number of punctures (1.2 in group A vs 2.9 in group B), a significantly shorter time for puncture in group A (mean 39 sec), but also a significantly higher skin exposure dosage in group A (mean 49.5 mSv surface dosage). There was no significant difference regarding the total procedure time. Only one complication occurred in group B (portobiliary fistula). CONCLUSION: CTF-guided initial puncture of bile ducts allowed a significantly reduced number of punctures and puncture times compared with puncture under conventional fluoroscopic guidance for placement of percutaneous transhepatic biliary drainage catheters.

[Virtual bronchoscopy in the child using multi-slice CT: initial clinical experiences]. / Virtuelle Bronchoskopie am Kind unter Verwendung der Mehrzeilen-Spiral-CT: erste klinische Erfahrungen.

PURPOSE: Virtual bronchoscopy of the pediatric patient has been reported to be more difficult because of artifacts due to breathing or motion. We demonstrate the benefit of the accelerated examination based on multislice spiral CT (MSCT) in the pediatric patient which has not been reported so far. MATERIAL AND METHODS: MSCT (tube voltage 120 kV, tube current 110 mA, 4 x 1 mm Slice thickness, 500 ms rotation time, Pitch 6) was performed on a CT scanner of the latest generation (Volume Zoom, Siemens Corp. Forchheim, Germany). In totally we examined 11 patients (median age 48 months, range 2-122 months) suspected of having tracheoesophageal fistula (n = 2), tracheobronchial narrowing (n = 8) due to intrinsic or extrinsic factors or injury of the bronchial system (n = 1). RESULTS: In all patients we obtained sufficient data for 3D reconstruction avoiding general anesthesia. 6/11 examinations were described to be without pathological finding. A definite diagnosis was obtained in 10 patients. Virtual bronchoscopy could avoid other invasive diagnostic examination in 8/11 patients (73%). CONCLUSION: Helical CT provides 3D-reconstruction and virtual bronchoscopy in the newborn as well as the infant. It avoids additional diagnostic bronchoscopy in a high percentage of all cases.

Better visualization of transbronchial biopsy using CT fluoroscopy.

PURPOSE: Computed tomography fluoroscopy (CTF) provides the capability for continuous CT imaging and has been increasingly used in interventional procedures. Our objective was to assess the usefulness of CTF in the monitoring of transbronchial biopsy procedures. METHODS: We evaluated nine patients in whom yield of "conventional" transbronchial biopsies had failed. CTF was performed on a Somatom Plus 4 Power scanner (CARE Vision CT, Siemens, Forchheim, Germany) using 120 kV, 50 mA at a frame rate of eight images per second on a matrix of 256 x 256. Image reconstruction was based on a partial scan with an acquisition time of 0.5 sec. The maximal time without interruption was 79 sec; after stopping for a few seconds a new period of 79 sec was available. The number of biopsies, procedure times, applied dose, and histologic results were documented. RESULTS: With CTF-guided transbronchial biopsy, the yield of the biopsies was improved. In seven patients biopsy yielded bronchial cancer; in one patient histopathologic examination showed tuberculosis. Only in one patient did CTF-guided transbronchial biopsy fail. The mean number of biopsies was four in each patient. Mean fluoroscopy time was 165 +/- 92 sec (range 111-272 sec) and mean procedure time was 800 +/- 302 sec (range 480-1081 sec). The applied dose ranged between 500 and 1224 mSv; the mean applied dose was 743 +/- 414 mSv. There were no fatal complications. CONCLUSION: Computed tomography fluoroscopy appears to facilitate visualization of transbronchial biopsy procedures, with the drawback of increased radiation exposure. To compare the "conventional" method versus CTF a randomized prospective study is necessary.

[Duodeno-ileal fistula development due to retroperitoneal lymph node metastases of sigmoid carcinoma]. / Duodenoileale Fistelbildung durch retroperitoneale Lymphknotenmetastasen eines Sigmakarzinomas.

We report on a 75-year-old patient suffering from persistent diarrhea with consecutive weight loss of 50 kg over a nine month period. Three years ago the patient had been operated on a sigmoid cancer. Ultrasonography and CT-scan revealed retroperitoneal masses due to lymph node metastases. Enteroclysis demonstrated a fistula between the duodenum and the terminal ileum. Whereas duodenocolic fistulae due to malignancies are well known to the best of our knowledge a fistula between retroperitoneal parts of the duodenum and the intraperitoneal intestine have not descripted so far.

Prevention of radiographic-contrast-agent-induced reductions in renal function by acetylcysteine.

BACKGROUND: Radiographic contrast agents can cause a reduction in renal function that may be due to reactive oxygen species. Whether the reduction can be prevented by the administration of antioxidants is unknown. METHODS: We prospectively studied 83 patients with chronic renal insufficiency (mean [+/-SD] serum creatinine concentration, 2.4+/-1.3 mg per deciliter [216+/-116 micromol per liter]) who were undergoing computed tomography with a nonionic, low-osmolality contrast agent. Patients were randomly assigned either to receive the antioxidant acetylcysteine (600 mg orally twice daily) and 0.45 percent saline intravenously, before and after administration of the contrast agent, or to receive placebo and saline. RESULTS: Ten of the 83 patients (12 percent) had an increase of at least 0.5 mg per deciliter (44 micromol per liter) in the serum creatinine concentration 48 hours after administration of the contrast agent: 1 of the 41 patients in the acetylcysteine group (2 percent) and 9 of the 42 patients in the control group (21 percent; P=0.01; relative risk, 0.1; 95 percent confidence interval, 0.02 to 0.9). In the acetylcysteine group, the mean serum creatinine concentration decreased significantly (P<0.001), from 2.5+/-1.3 to 2.1+/-1.3 mg per deciliter (220+/-118 to 186+/-112 micromol per liter) 48 hours after the administration of the contrast medium, whereas in the control group, the mean serum creatinine concentration increased nonsignificantly (P=0.18), from 2.4+/-1.3 to 2.6+/-1.5 mg per deciliter (212+/-114 to 226+/-133 micromol per liter) (P<0.001 for the comparison between groups). CONCLUSIONS: Prophylactic oral administration of the antioxidant acetylcysteine, along with hydration, prevents the reduction in renal function induced by contrast agents in patients with chronic renal insufficiency.

Optimized enhancement in helical CT: experiences with a real-time bolus tracking system in 628 patients.

AIMS: Ultrafast detector technology enables bolus-triggered application of contrast media. In a prospective study we investigated the benefit of this new method with the intention of optimizing enhancement during examination of the chest and abdomen. MATERIALS AND METHODS: In total, we examined 548 patients under standardized conditions. All examinations were performed on a Somatom Plus 4 Power CT system (Siemens Corp., Forchheim, Germany) using the CARE-Bolus software. This produces repetitive low-dose test images (e.g. for the lung: 140 kV, 43 mA, TI 0.5 s) and measures the Hounsfield attenuation in a pre-selected region of interest. After exceeding a defined threshold, a diagnostic spiral CT examination was begun automatically. The data obtained from 321 abdominal CT and 179 lung CT examinations were correlated with different parameters such as age, weight and height of the patients and parameters of vascular access. In a group of 80 patients, the injection of contrast medium was stopped after reaching a pre-defined threshold of an increase of 100 HU over the baseline. Then, we assessed the maximal enhancement of liver, pulmonal artery trunk and aortic arch. RESULTS: There was no correlation between bolus geometry and age, body surface or weight. In helical CT of the abdomen the threshold was reached after a mean trigger time of 27 s (range 13-67 s) and only 65 ml (range 41-105 ml) of contrast medium were administered. In helical CT of the lung the threshold was reached after 21 s (range 12-48 s) and the mean amount of administered contrast medium was 48 ml (range 38-71 ml). CONCLUSION: Bolus triggering allows optimized enhancement of the organs and reduces the dose of contrast material required compared with standard administration.

CTF-guided puncture of an unenhanced isodense liver lesion during continuous intravenous injection of contrast medium.

CT fluoroscopy (CTF) facilitates guidance of percutaneous biopsies and other interventional procedures. We wished to demonstrate the usefulness of CTF for the puncture of an unenhanced isodense liver lesion during continuous injection of intravenous contrast medium. We performed CTF-guided puncture of a 2-cm lesion in the liver of a patient suffering from lung cancer. CTF enables puncture of liver foci even if they are unenhanced and isodense with the surrounding parenchyma.

First experiences in percutaneous arterial chemoembolization of malignant liver lesions by means of real-time CT fluoroscopy.

Computed tomography fluoroscopy (CTF) allows real-time display (continuous imaging) and has been increasingly used in interventional procedures. We wished to demonstrate the usefulness of CTF in chemoembolization of the liver. Twenty-one patients with primary or secondary malignant lesions of the liver underwent CTF-guided chemoembolization after angiographic positioning of a catheter in the hepatic artery. Embolization materials such as Lipiodol and mitomycin C were administered under continuous CT scanning. CTF led to a change of the method (correction of catheter position, application of norepinephrine) in nine of 21 cases. There were no fatal complications.

[Intramural pseudodiverticulosis of the esophagus. Diagnosis on second look]. / Intramurale Pseudodivertikulose des Osophagus. Diagnose auf den zweiten Blick.

HISTORY: Case 1. A 56-year-old man had experienced increasing dysphagia for 6 months, accompanied by a weight loss of 20 kg. A stenosing oesophageal carcinoma was suspected. Case 2. A 82-year-old man had been suffering intermittently from nausea for some years but had maintained his weight (80 kg; height 173 cm). Endoscopy 4 months before this admission had revealed a duodenal ulcer; its treatment briefly improved the symptoms. INVESTIGATIONS, DIAGNOSIS AND TREATMENT: Endoscopy in case 1 detected a severe oesophageal stenosis which could not be passed, and its cause could not be ascertained despite biopsy, barium swallow and computed tomography. After bougie dilatation an endoscope was finally passed and the typical picture of oesophageal pseudodiverticulosis (OPD) seen. In case 2, endoscopy at first indicated only marked Candida oesophagitis. But after antimycotic treatment a second endoscopy revealed OPD. No treatment is known nor necessary since OPD causes no clinical symptoms unless there are complications. CONCLUSIONS: OPD, a rare condition, presents in various ways, both in its symptoms and at endoscopy. In case of oesophageal stenosis of unknown cause or Candida oesophagitis repeat endoscopy my be necessary to establish the true diagnosis: OPD should be included in the differential diagnosis.

[Minimally invasive stereotactic breast biopsy with the "mammotome". Methodology and personal experiences]. / Minimal-invasive stereotaktische Mammabiopsie mit dem "Mammotome". Methodik und eigene Erfahrungen.

A new method of minimally invasive breast biopsy is described. The system components are a stereotactic biopsy table, a digital mammography, an automatic, computer-assisted needle positioning device and a new vacuum core biopsy needle. With this needle multiple core biopsies can be collected through a single insertion. The procedure was performed as outpatient status and was very well tolerated by the patients. Our experiences with this method are very promising. The method will reduce the relation of benign to malignant histology in open biopsies.

Magnetic resonance angiography as a technique for the visualization of hemodialysis shunts.

In order to test the suitability of magnetic resonance angiography for the visualization of Brescia-Cimino hemodialysis shunts, 20 patients (8 women, 12 men, aged 24-69 years) were examined with this technique. The shunt arm was placed in an extremity coil. The time-of-flight method was applied. Examination time was less than 15 min. Arterial digital subtraction angiography (DSA) of the shunt arm was carried out additionally in 8 patients in whom pathological results had been obtained. Surgery was performed on 2 patients. In all cases, the feeding artery, anastomosis, and shunt were clearly visible. The results corresponded exactly to those of DSA and, in the patients who had undergone surgery, also to the situs. The patients stated that the examination technique was not very disturbing. Magnetic resonance angiography in the time-of-flight technique seems to be recommendable for the examination of Brescia-Cimino dialysis shunts. Compared to DSA, it has major advantages: it is noninvasive, and no ionizing radiation or contrast medium are associated with the procedure.

[MRI characteristics of the Sneddon syndrome]. / MRI-Charakteristik des Sneddon-Syndroms.

The report describes the MRI findings in a female patient with an established long course of a Sneddon's syndrome. Multiple ischaemic cerebral infarcts of a mainly macroangiopathic pattern are typical. In the beginning the corresponding clinical deficiencies often show a considerable regression.