A typical characteristic of the ongoing practice of democracy in Singapore has been described by some scholars as 'illiberal democracy'. Noting that Singapore 's brand of democracy operates within a 'dominant, one-party system', other scholars cushioned such a democratic practice by their reference to 'semi-democracy', 'controlled democracy, 'guided democracy, and 'communitarian democracy'. However, despite the demonstration that there are many restrictions in the type of democracy that exists in Singapore, the benefits are numerous. Singapore is the only country in the world to have transformed itself from a developing country to a developed country in less than only forty years. But its slower move towards a culture ofparticipation must move as quickly as globalization does if it is to remain in relevant and legitimate democracy. If the younger generation understands that they should have the right to a voice before the government acknowledges it, the transition could be more tumultuous than necessary.
The present study was undertaken to assess the clinical use of power Doppler (PD) as a new tool for transcranial vessel imaging. Power Doppler displays the integrated power of the Doppler signal instead of the Doppler frequency shift used in the conventional color flow Doppler (CFD) technique. Twenty-one patients were evaluated who had intracranial malformations or arterial stenoses [4 middle cerebral artery (MCA) stenoses, 2 intracranial carotid stenoses, 7 arteriovenous malformations (AVM), 5 intracranial carotid aneurysms, 3 Moya-Moya syndromes]. The PD results were compared with those obtained from CFD and digital subtraction angiography (DSA). Power Doppler was able to visualize 3 of 4 MCA stenoses with greater morphological detail than CFD, whereas PD and CFD were equally effective in diagnosing carotid stenoses. All AVMs were visualized using PD as well as CFD, but again PD revealed more morphological details, in a manner similar to DSA. Power Doppler was also superior to CFD in imaging intracerebral aneurysms and pathological collateralization associated with Moya-Moya syndromes. It is evident from these data that PD permits reliable and detailed transcranial imaging and therefore is a superior method for visualizing intracerebral vascular malformations and arterial stenoses.
Acute appendicitis is one of the most frequent causes of an acute abdomen. The clinical diagnosis is based on the case history and the physical examination which plays a major role in clinical diagnosis. However, in some cases the typical clinical symptoms are equivocal or misleading. Without using the opportunities of diagnostic imaging the accuracy of preoperative appendix diagnosis ranged between 70 and 78%. Consequently the rate of unnecessary laporotomies ranged between 22 and 28%. Since 1986, 13 studies including more than 5,000 patients have been published showing a sensitivity of 85% and a specificity of 96% if the sonographic examination was performed by an experienced examiner. The rate of negative laparotomies could be decreased to 7%, and possible differential diagnoses could be either confirmed or ruled out by using ultrasound technique. Based on the current literature, real-time sonography plays a major part in the diagnosis of acute appendicitis.
Stenosis of a vessel is a well-known reason for increased resistance leading to lower flow rates. Other anomalies of the shape or additional blood influx are often considered to be less influential on flow dynamics inside the vessel. In this report, examples of irregular flow patterns in the human aorta are presented. The cases were selected from magnetic resonance examinations of 25 volunteers and more than 150 patients with dysfunctions of the heart or anomalies of the thoracic vessels. The protocol for magnetic resonance examinations included black blood imaging performed in the cine mode (with ECG triggering). Even minor modifications of the aortic shape are shown to result in marked disturbances of the laminar flow pattern in some patients. Effects of abnormal curvatures, additional blood influx, stenoses and dilatation of the aorta are demonstrated.
Sonographic evidence of a cystic adrenal tumour was found in a 73-year-old female patient with a 6-month history of chest pain and dyspnoea. A computed tomogram of the abdomen revealed, in addition to the 5-cm lesion, a contrast medium-free area in the vena cava inferior, leading to an initial diagnosis of recurrent pulmonary emboli due to a thrombosis of the vena cava inferior. Further diagnostic procedures excluded emboli and indicated a dilating cardiomyopathy with mitral and tricuspid regurgitation. The contrast medium-free area in the vena cava inferior was caused by the influx and regurgitation of contrast medium-free blood from the renal and hepatic veins in addition to blood from the right atrium due to the tricuspid valve regurgitation. A thrombosis was excluded by means of a color-duplex investigation. The patient declined any further diagnostic procedures concerning the lesion.
To evaluate the use of Gd-DTPA in imaging epithelial skin tumors and tumor-like lesions, 29 benign, 8 malignant and 4 semimalignant skin tumors were prospectively examined by high-resolution MRI at 1.5 Tesla using a 2.5-cm surface coil. For tumor assessment, transverse plain and contrast-enhanced scans (0.1 mmol Gd-DTPA/kg body mass) were performed (TR 500 ms, TE 25 ms, 3 acquisitions, 256 x 256 matrix, FOV 2.5 cm). Contrast enhancement was quantitively determined as the percent enhancement of signal intensity. Histologic findings were correlated using the Mann-Whitney-test (p < 0.05). Quality of contrast enhancement was independently assessed by three investigators, who mostly described inhomogeneous enhancement, regardless of histologic findings. Malignant tumors could not be differentiated from benign lesions by contrast enhancement. MRI using Gd-DTPA does not provide differentiation of skin tumor types.
In a retrospective study, the authors evaluated the signal behavior of 150 patients after intervention in the breast (40 fine-needle biopsies, 10 core biopsies, 50 open biopsies, 50 tumor-ectomies with additional irradiation therapy). The MR imaging was performed on 1.5-Tesla whole-body scanners using T1-WI GRE sequences in 2D FLASH technique before and 5 times after i.v. application of 0.1 mmol gadopentetate-dimeglumine per kg body weight. There was no signal enhancement after fine-needle biopsy. Hematoma due to core biopsy caused signal increase in every 5th patient. Enhancement after open biopsy was no more visible 6 months postoperatively. 12 months after tumorectomy and radiation therapy, most patients showed no more signal enhancement. In conclusion, MR mammography can be performed after fine-needle biopsy without problems. In case of core biopsy, hematoma should be excluded by sonography before. MR mammography should not be performed within 6 months after open biopsy, or within 12 months after tumorectomy and radiation therapy.
The presentation of gastric ulcer healing taken from video endoscopy as a dynamic process could not be realized till now. The documentation of the dynamic healing process shattered either on the patient's compliance or on the inconstancy of the image cut due to wobbling. The replay should be performed as a time lapse whereby the picture disturbances would become an essential part.-Instead of presenting a continuous film, instant takes of ulcer healing were processed. A dynamic effect was produced by computer-assisted production of intermediate pictures. A video was created in which short video sequences in definite time intervals were recorded endoscopically. Single stills-so-called original pictures-fitting together from each sequence were selected and spliced together. The missing intermediate pictures were made with a special computer technique according to the mathematical concept of interpolation. With this technique, the dynamic documentation of gastric ulcer healing in a 47-year-old male patient was performed. The technique enables an almost natural and real observation of ulcer healing and promises new physiological and patho-physiological knowledge in gastroenterologic endoscopy.
Multicentric reticulohistiocytosis (MR) is a rare systemic disease of unknown cause. The disease is characterized by tissue infiltration of lipid-laden histiocytes and multinucleated giant cells. Destructive polyarthritis and skin lesions are the most common findings. The disease becomes apparent in adult life. We report on 3 patients and discuss the specific radiographic characteristics of bone and joint involvement. The radiologic feature is a bilateral, symmetric joint involvement with predilection for the interphalangeal and metacarpophalangeal joints. In all of our cases we found an early involvement of shoulder joints. Erosive arthritis begins at the margins of the joints, progressing to osseous defects and to severe joint destruction. In contrast to rheumatoid arthritis, periarticular osteoporosis and early joint space loss are absent in MR. In addition, significant erosions of distal interphalangeal joints are not common in rheumatoid arthritis.
The value of color-coded duplex sonography in the assessment of combined kidney and pancreatic transplantations (KTX/PTX) was studied in 9 patients. In normal graft function the median resistive index (RI) was 0.69 (range 0.60-0.80) for the kidney and 0.61 (range 0.55-0.70) for the pancreas. Ten episodes of graft dysfunction (kidney n = 4; pancreas n = 6) were observed. During renal rejection and hemolytic uremic syndrome the RI was above 0.80. In pancreatic rejection the RI exceeded 0.80 while all other causes of pancreatic dysfunction were not associated with changes in the RI. Color-coded duplex sonography may prove to be a reliable noninvasive diagnostic method in the evaluation of the posttransplant course after combined KTX/PTX, in particular in the diagnosis of pancreatic rejection.
The purpose of this study was to investigate the morphology of reactive lymph nodes of the neck in ultrasound and its histological implications. By revealing a characteristic sonomorphology of reactive lymph nodes we would like to contribute to the differential diagnosis of cervical lymph node enlargements. In 81 patients the morphology and the longitudinal/ transverse axis ratio (L/T ratio) of 257 reactively enlarged lymph nodes were examined. Besides 6 false-positive cases the L/T ratio turned out to be a reliable instrument in detecting reactive lymph nodes. Concerning the nodal texture, 89 lymph nodes (34.6%) appeared homogenously. Those lymph nodes which demonstrated a more complex nodal texture could be assigned to three sonomorphological groups: In 134 lymph nodes (52.1%) a centrally located echogenoic line ("central echogenoic line', CEL) was observed. Its maximal diameter was defined to be maximally up to one third of the lymph node width. In the histological examination this CEL could be identified as a widened hilus with an increased fibrosis. An echogenoic nodal area measuring between one third up to one half of the lymph node width demonstrated histologically a fatty replacement of the hilar tissue. This "echogenoic hilus reflex' occurred in 28 lymph nodes (10.9%). A nearly complete lipomatous atrophy of the lymph node parenchyma was found in 6 lymph nodes (2.4%) demonstrating a "central echogenicity' with just a small peripheral, less echogenoic border corresponding to the remaining parenchyma.
Surgical treatment of benign bile duct strictures continues to be associated with significant lethality. Thus, radiological interventions become increasingly important. A total of 32 patients were treated. Their bile duct strictures had different origins. We performed percutaneous transhepatic cholangiographies in 32 patients, cholangioscopies in 7, and biopsies in 2 patients. Therapeutic interventions included percutaneous transhepatic drainages in 30 patients, laser lithotripsies in 5, and dilatations in 8 patients. As a total, 36 stents (mostly Palmaz stents) were implanted in 27 patients. Acuflex stents were implanted in 2 of these patients and were extracted after successful clearance of the bile ducts following stone fragmentation. No severe complications were observed. Five out of 8 dilatations were unsuccessful, so that stents were implanted. Five patients died. Three stent occlusions and 1 spontaneous stent migration occurred after an average of 29 months; the latter could be treated by means of radiological procedures. The remaining patients are living symptom-free, on average, since 18.6 months.
Hepatic trauma remains one of the most serious problems in abdominal injury. Whenever possible a non-resectional approach is clearly preferred. Refinements of interventional radiology as an adjunct to surgery in blunt liver trauma may play an increasingly vital role in reducing mortality. The literature is reviewed with reference to the diagnostic procedure and the treatment strategy in blunt liver trauma.
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.
Cholangioscopy in the mother-baby technique is well accepted and widespread these days. On the other hand, the peroral pancreaticoscopy (POPS) is still in the initial phase of development. In cases of doubtful stenoses, duct discontinuation, and radiolucent shadows during an endoscopic retrograde cholangiopancreatography (ERCP) the POPS can be carried out as a clarifying examination. Two variations of babyscopes are currently available. The ultra-thin endoscope allows only limited results due to the lack of tip control and irrigation. On the other hand, devices with an outer diameter of 3.2 mm and larger provide for a sufficient assessment of the duct mucosa. Biopsies can be taken through the working channel, and the probes for intracorporeal shock wave lithotripsy (ISWL) can be placed under visual control. We performed POPS on 9 patients with an average age of 60 years using a tip-controlled endoscope. In 8 of these cases a diagnostic or therapeutic advantage was gained. A 29-year old patient with alcohol-induced chronic pancreatitis and an occluding duct stone underwent electrohydraulic lithotrips (EHL). A 60-year-old patient with pancreatic duct stones underwent laser-induced shock wave lithotripsy (LISL) in 2 sessions. Afterwards remaining parts of the calculi were extracted. The importance of this method in diagnosis and therapy of pancreatic diseases remains to be established, as evaluation studies of any great extent are still to be done.
We are reporting the case of a 94-year-old male patient with a 10-year history of Parkinson's disease, who was admitted to our hospital with acute obstruction of esophageal passage. Esophageal obstruction was refractory to endoscopic intervention. However, discontinuation of the pre-existing levodopa medication led to its resolution within hours. While dysphagia is commonly encountered in patients with Parkinson's disease, the observed succession of drug discontinuation and resolution of obstruction in this case suggests an as yet rarely described side effect of levodopa. This potential side effect should be included in the differential diagnosis of dysphagia in Parkinson's disease, especially in the case of older patients, who may exhibit an increased rate of intestinal absorption of levodopa.
Imaging procedures are important for diagnosis and surveillance of patients in intensive care units. Radiologic examination, ultrasound and echocardiography are of paramount importance because they can be done bedside. Portable chest x-ray examination is the procedure of choice for documentation of tubes, lines and devices, estimation of cardiopulmonary function, demonstration of pulmonary edema, ARDS pneumonia, atelectasis and pneumothorax Plainfilm radiologic imaging of the abdomen is indicated when perforation ileus or acute intestinal pseudoobstruction is suspected Echocardiography can give information about ventricular function, pericardial effusion, cardiac valves, functional importance and complications of myocardial infarction, and hemodynamic changes of pulmonary embolism. Transesophageal echocardiography (TEE) is the method of choice when endocarditis, aortic dissection or cardiac thromboembolism is considered. Ultrasound can show many pathologic changes important for the management of intensive care patients concerning liver, gallbladder, bile duct, pancreas, kidney, spleen, pleural space and vessels. Other imaging procedures such as CT, methods of nuclear medicine, MRT, angiography etc. are done outside the intensive care unit and therefore need a more restricted indication.
The frequent detection of benign liver lesions during ultrasound routine examination and a possible curative therapy of early detected malignant tumors require a reliable method of differentiation. Conventional gray-scale ultrasound, according to this problem, has been extended by the Duplex technique and color Doppler ultrasound. Measurement of blood flow velocity by Doppler in the center and at the periphery of liver lesions is not reliable enough to distinguish between benign and malignant lesions. Color Doppler ultrasound possesses some reliable criteria for differentiation. A central spot could be detected in 2 out of 12 hemangiomas, a giant spot in 1 out of 3 giant cavernous hemangiomas. The halo sign without detectable blood flow is considered to be specific for malignancy. We found this sign in 26 out of 81 malignant liver lesions and only in one benign lesion (sensitivity 32%, specificity 97%). The vascularization of focal liver lesions is excellently demonstrated with color Doppler ultrasound. This is very helpful for the diagnosis (e.g. "chaotic blood vessel architecture' in malignant tumors) and for the therapy of focal liver lesions (e.g. follow-up examinations after chemotherapy or chemoembolization). Therefore, application of Duplex and color Doppler ultrasound is highly recommended as a noninvasive diagnostic method of first choice for unknown liver lesions.
