Coronary artery fistula diagnosed by transthoracic Doppler echocardiography.

A 47-year-old Malay woman complained of an episode of shortness of breath after a shower. There was no previous complaint of shortness of breath or chest pain. Physical examination revealed a wide pulse pressure. Blood pressure was 160/66 mmHg, and heart rate was 77/minute and regular. What was initially thought to be a loud pansystolic murmur was heard over the precordium. Electrocardiography showed left ventricular hypertrophy with a volume overload pattern. Transthoracic Doppler echocardiography revealed a right coronary artery-right ventricular fistula, arising from the right coronary artery and draining into the right ventricular cavity.

Cartilage injury and repair: assessment with magnetic resonance imaging.

Articular cartilage damage plays a major role in joint degeneration and dysfunction. Accurate assessment of the morphology and degree of cartilage wear is important in diagnosis, prognosis and management, particularly as many of these patients are young or participate in high-performance sports. Magnetic resonance imaging is able to directly evaluate such injuries, due to its high spatial resolution and excellent soft-tissue contrast resolution. This pictoral essay aims to demonstrate normal and damaged articular cartilage on MR imaging, as well as surgically-repaired cartilage.

Radiographic features of a case of severe acute respiratory syndrome with fatal outcome.

INTRODUCTION: Severe acute respiratory syndrome (SARS) is a new form of atypical pneumonia caused by a coronavirus. We present the clinical course and chest radiographic findings of a case of SARS with fatal outcome. CLINICAL PICTURE: A 39-year-old Chinese male presented with fever, sore throat and non-productive cough. During his illness, serial chest radiographs showed increasingly severe air-space shadowing in both lungs. TREATMENT AND OUTCOME: The patient was treated with supplemental oxygen, levofloxacin, oseltamivir, ribavirin and methylprednisolone. As his condition worsened, the required ventilatory and inotropic support. He later developed a myocardial infarct and coagulopathy, and succumbed to his illness. CONCLUSION: The reported case mortality of SARS is about 9% worldwide. In Singapore, the mortality is 15.5%. Acute respiratory distress syndrome (ARDS) is believed to be a contributory factor to our patient's demise. We report this case to show the radiographic changes of ARDS in a patient with SARS.

Chest radiographic findings of a case of severe acute respiratory syndrome (SARS) in Singapore.

A new form of atypical pneumonia was reported in the East Asian region beginning from early 2003. This was later termed by the World Health Organisation as Severe Acute Respiratory Syndrome (SARS). The diagnosis of SARS relies on a combination of clinical features and chest radiographic findings. A preliminary review of SARS in Singapore shows chest radiographic findings of patchy airspace shadowing with severe cases progressing to diffuse air-space shadowing. We illustrate these findings with temporal correlation in our case report. As SARS is a contagious, rapidly progressive and potentially fatal condition, early diagnosis is crucial for prompt management and isolation of patients. Recognition of chest radiographic findings aids in the early diagnosis and containment of SARS.

Percutaneous vertebroplasty in the management of osteoporotic vertebral compression fractures: initial experience.

INTRODUCTION: Vertebral compression fractures related to osteoporosis may cause persistent pain which impairs mobility and reduces the quality of life. Percutaneous vertebroplasty is a therapeutic interventional radiology procedure which is used in the management of pain relief in such fractures. It involves the injection of bone cement [polymethylmethacrylate (PMMA)] into the collapsed vertebrae under radiological guidance. This provides pain relief as well as increases the strength and stability of the vertebra. MATERIALS AND METHODS: A total of 16 patients with 17 osteoporotic compression fractures which were treated with percutaneous vertebroplasty over an 18-month period were studied. There were all women with the exception of 1 male patient. Their ages ranged from 61 to 87 years. The fracture sites were at the thoracolumbar junction from T12 to L3 levels. The majority of cases only required a unipedicular injection, with bipedicular injections in 3 cases. All cases were performed in the angiographic suite in the radiology departments, with biplanar fluoroscopy in one hospital. PMMA was injected in a semi-solid state under radiological guidance and screening into the collapsed vertebrae. RESULTS: All cases showed good technical success with no mortality or major complications. Only 2 cases had minor complications of cement leakage into the soft tissues of the back and adjacent disc space, respectively. There was sufficient pain relief in all patients and they were well enough to be discharged within 1 to 5 days after the procedure. Patients were followed up to evaluate the degree of long-term pain relief as well as analgesic usage. CONCLUSION: Percutaneous vertebroplasty is a new and minimally-invasive modality of treating pain in patients with osteoporotic compression fractures who are refractory to medical therapy. Under adequate imaging guidance, the risks of complications are minimal while the potential benefit to patients and their care-givers are significant.

Differentiation of malignant vertebral collapse from osteoporotic and other benign causes using magnetic resonance imaging.

INTRODUCTION: Elderly patients presenting with backache and vertebral collapse are a diagnostic challenge. Plain X-rays, computed tomography and radionuclide bone scans have not always reliably distinguished between benign and malignant causes. Magnetic resonance imaging (MRI) may be able to do so. MATERIALS AND METHODS: Patients who underwent MRI evaluation for vertebral collapse were retrospectively studied. Over a 21-month period from January 1995 to September 1996, 47 patients with 58 vertebral collapses were studied. Benign and malignant aetiologies were established by serial imaging, clinical outcome and histology. Imaging was performed with T1 and T2-weighted sequences, with contrast enhancement in some patients. Collapsed vertebrae were examined for appearance of marrow on T1 and T2-weighted sequences and after contrast administration, signal intensity of adjacent discs, degree of marrow involvement, involvement of posterior elements, presence or absence of paraspinal mass and end-plate integrity. Agreement between the final and radiological diagnosis was evaluated. RESULTS: There were 36 benign vertebral collapses (20 osteoporotic, 7 post-traumatic, 9 infective) and 22 malignant ones (20 metastatic carcinoma, 2 multiple myeloma). Features which pointed to malignant cause were hypointense marrow on T1-weighted images, marrow enhancement after intravenous contrast, greater than 50% marrow involvement and involvement of posterior elements. Of the vertebral collapses due to infection, 78% showed end-plate disruption. CONCLUSIONS: This study shows that MRI can be used to accurately differentiate between benign and malignant causes of vertebral collapse. Further differentiation between an osteoporotic, traumatic or infective cause can be done with the help of clinical history and evaluation of end-plate integrity.

Nocardiosis in patients with systemic lupus erythematosus. The Singapore Lupus Study Group.

Nocardia, a gram positive variably acid-fast aerobic bacterium is an opportunistic pathogen in immunocompromised hosts. We present 5 cases of nocardiosis in patients with systemic lupus erythematosus. We emphasize the clinical features, radiologic findings, and antibiotic sensitivity. Lung involvement was the predominant manifestation; others include brain abscess, retinitis, thyroiditis, and diaphragmatic infiltration. We describe the first cases of pulmonary nocardiosis presenting as pneumothorax and the use of fine needle aspiration cytology in diagnosing nocardial thyroiditis.

Nipah viral encephalitis or Japanese encephalitis? MR findings in a new zoonotic disease.

BACKGROUND AND PURPOSE: An epidemic of suspected Japanese encephalitis occurred in Malaysia in 1998-1999 among pig farmers. In neighboring Singapore, an outbreak occurred among pig slaughterhouse workers. It was subsequently established that the causative agent in the outbreak was not the Japanese encephalitis virus but a previously unknown Hendra-like paramyxovirus named Nipah virus. METHODS: The brain MR images of eight patients with Nipah virus infection were reviewed. All patients tested negative for acute Japanese encephalitis virus. Seven patients had contrast-enhanced studies and six had diffusion-weighted examinations. RESULTS: All patients had multiple small bilateral foci of T2 prolongation within the subcortical and deep white matter. The periventricular region and corpus callosum were also involved. In addition to white matter disease, five patients had cortical lesions, three had brain stem involvement, and a single thalamic lesion was detected in one patient. All lesions were less than 1 cm in maximum diameter. In five patients, diffusion-weighted images showed increased signal. Four patients had leptomeningeal enhancement and four had enhancement of parenchymal lesions. CONCLUSION: The brain MR findings in patients infected with the newly discovered Nipah paramyxovirus are different from those of patients with Japanese encephalitis. In a zoonotic epidemic, this striking difference in the appearance and distribution of lesions is useful in differentiating these diseases. Diffusion-weighted imaging was advantageous in increasing lesion conspicuity.

Temporomandibular disorders in rheumatoid arthritis.

OBJECTIVE: To determine the frequency and character of temporomandibular disorders (TMD) in Oriental patients with rheumatoid arthritis (RA) and to investigate the relationship between TMD and RA in a tertiary referral center. METHODS: Symptoms and signs related to TMD were investigated in 80 patients (67 female, 13 male) who fulfilled the American College of Rheumatology 1987 revised criteria for RA. Diagnoses of TMD including muscle, disk displacement, or temporomandibular joint (TMJ) disorders were made based on clinical assessment. TMJ disorder was then correlated with the clinical, laboratory, and radiological features of RA. RESULTS: The mean age of the study population was 49.7 years and the mean duration of RA was 86.9 months. Eleven patients (13.8%) had active RA at the time of TMD assessment. About 76% of the study population had seropositive disease and 62% had peripheral joint erosions. Osteoarthrosis of the TMJ was the most common TMD in this Oriental population. Joint sounds on opening (35%), joint sounds on moving sideways or forward (27.5%), and pain in jaw joints (23.7%) were common TMD symptoms. Deviated mouth opening (45%) and coarse crepitus (15-21.3%) were most prevalent on examination. CONCLUSION: Patients with RA who had prolonged disease duration of RA and active peripheral joints tended to have osteoarthrosis of the TMJ. Presence of rheumatoid factor or peripheral joint erosions was not associated with TMJ osteoarthrosis.

Overview of imaging in rheumatologic diseases.

The role of radiology in rheumatologic diseases has for many years been confined to conventional radiography alone. The advances in medicine placed great demands on earlier and more accurate evaluation of these diseases. Conventional radiographs have been used as diagnostic aids and radiographic features and measurements are well established. However, the newer technologies, such as ultrasound, computed tomography and magnetic resonance imaging (MRI) have recently influenced accuracy of diagnosis and allowed for earlier detection and a more comprehensive evaluation of the results of therapy. One leading example is the significant role MRI plays in the early detection of avascular necrosis, especially of the hips. The clinical benefits of the newer modalities in radiology are being increasingly recognised and its full potential realised by both rheumatologists and radiologists.

MRI of the fornix and mamillary body in temporal lobe epilepsy.

We performed MRI on 27 patients with clinically proven temporal lobe epilepsy (TLE), all with prior EEG lateralisation, and 10 volunteers, studied to evaluate disparity in size arising from biological variation (group 1). Three-dimensional spoiled GRASS (3DSPGR) sequences provided 2-mm contiguous sections of the limbic system, enabling assessment of the hippocampus (HC), fornix (FN) and mamillary body (MB). Measurements of FN and MB width were made from a workstation. Any percentage difference in size was computed. In 19 cases there was unilateral abnormality in the HC (group 2); in 18 and 19 cases respectively there was a smaller FN and MB on the same side as the abnormal HC. This percentage difference in size was significantly greater than that in group 1 in the FN and MB in 17 and 17 cases respectively. Comparison of percentage difference computations for FN and MB between groups 1 and 2 showed high statistical significance (P < 0.0002). In 5 patients with clinical TLE the HC was normal on MRI (group 3). Unequal FN and MB sizes were found in 4, significant in 2. Comparison of percentage difference computations for FN and MB showed statistical significance (P < 0.0005 and P < 0.0003 respectively). There was no case of discordance between the sides of hippocampal abnormality and the smaller FN or MB or between the sides of smaller FN and MB. The strong concordance between the changes in the HC and those in the FN and MB suggests that this combination will play an important role in the assessment of TLE and limbic system abnormality.

The lumbosacral lucent cleft.

BACKGROUND: The lumbosacral lucent cleft was first described in association with traumatic injuries to the neck. However, we have observed this sign to be present in patients with no precursor of trauma, and we reviewed the incidence of lucent cleft sign in our local population and any characteristic features of the lucent cleft. METHODS: Four-hundred and thirty lumbosacral spine radiographs were examined prospectively over an 8-month period, with correlation with clinical findings. Follow-up radiographs were obtained at 1, 3 and 6 months for patients with the lucent cleft sign. FINDINGS: Nineteen patients (4.4%) were found to have lucent clefts in their lumbosacral spine X-rays. No significant change in the number and features to the lucent clefts was noted even when the symptoms had resolved after 6 months. All the lucent clefts were linear, horizontally oriented and located at the anterior edge of the adjacent vertebral body. CONCLUSION: The lucent cleft sign in the spine, which has so far been described in association with has spinal trauma may be completely innocuous in patients with little or no symptoms.

Neuronal migration disorder presenting with epilepsy: a report of five illustrative cases.

Neuronal migration disorders are an uncommon but well-recognised cause of medically intractable epilepsy. The increasing availability of magnetic resonance imaging of the brain has made it possible to diagnose this condition ante-mortem. There are several types of migration disorders, each with different radiological and clinical features. A case each of focal cortical dysplasia, focal subcortical heterotopia, double cortex syndrome, periventricular nodular heterotopia and closed lip schizencephaly is presented to highlight the distinctive features of each entity.

Clinical utility, safety, acceptability and complications of transoesophageal echocardiography (TEE) in 901 patients.

Transoesophageal echocardiography (TEE) has earned an important role in the evaluation of patients with cardiovascular diseases. We report our TEE experience in 901 patients who had suboptimal transthoracic echocardiographic studies performed between September 1989 and June 1993. The patient-population consisted of 459 females and 442 males, with an ethnic distribution of Chinese 76.5%, Malays 12.7%, Indians 8.5% and Others 2.3%. The mean age was 48 years. The main indications for TEE were: cardiac source of embolism (27.5%); native valve pathology (19.1%); atrial septal abnormality (9.7%); infective endocarditis (8.3%); intracardiac masses (7.0%); prosthetic valve dysfunction (6.3%); congenital heart diseases (4.6%); aortic diseases (3.4%) and miscellaneous (14.1%). The majority of the studies were done on in- and out-patients, with only 1.2% performed in the intensive care area and 1% intraoperatively. 82.6% of TEE intubation were accomplished within one minute and most of the TEE studies were completed within twenty minutes. There were ten failures (1.2%). Major complications occurred in 5 patients (0.6%) but there was no mortality. 90.5% of the studies were considered by the operators as additionally-informative or useful for clinical decision making. In a subgroup analysis, 90.6% of the patients who had undergone TEE indicated their willingness for repeat studies if required and TEE was able to increase the sensitivity of detecting a potential cardioembolic source from 10.3% to 29.5%. In conclusion, with increasing experience, TEE can be performed expeditiously and safely, with good acceptability by our local population. TEE provides useful or additional information that supplements standard transthoracic echocardiography in a wide-ranging spectrum of cardiac conditions.

Percutaneous balloon valvuloplasty in mitral restenosis after previous surgical commissurotomy.

OBJECTIVES: The aim of this study was to determine the safety profile, mitral valve outcome and follow-up functional status after percutaneous balloon mitral valvuloplasty (PBMV) in patients with mitral restenosis post-surgical commissurotomy. METHODS: Sixteen patients with symptomatic mitral restenosis after previous surgical commissurotomy underwent valvuloplasty using the Inoue balloon stepwise dilatation method. Echocardiography was performed before and after the procedure to evaluate the mitral valve area. RESULTS: All procedures were successfully completed without cardiac perforation, thromboembolism, resultant severe mitral regurgitation or death. The mitral valve area improved from 0.9 +/- 0.2 to 1.6 +/- 0.3 (p = 0.0001), accompanied by a significant immediate reduction in the left atrial pressure and transmitral gradient. Compared with PBMV in patients without past mitral surgery, patients with mitral restenosis undergoing PBMV experienced less valve area improvement but the difference was not significant (p = 0.137). Optimal valve enlargement resulting in mild mitral stenosis was achieved in 12 of the 16 patients. Midterm symptomatic benefit was observed in almost all patients. CONCLUSIONS: In view of the excellent success rate, low complication risk, the optimal haemodynamic results and favourable functional outcome afforded by mitral balloon valvuloplasty in patients with mitral restenosis after prior surgical commissurotomy, it is logical that balloon mitral valvuloplasty, where available, should be the initial treatment modality in this group of patients with suitable valve morphology before considering repeat mitral surgery.

Hypertension in disguise--a trap for the unwary.

A 36-year-old asymptomatic Chinese male with polycystic kidney disease (PKD) developed hypertension 1 year after the diagnosis of PKD. The patient was treated initially as for hypertension associated with PKD. However, over a 6-year period his hypertension became progressively difficult to control and he developed severe symptomatic hypokalemia. Subsequent investigations confirmed the presence of primary hyperaldosteronism. The initial computed tomographic scans of the adrenals did not reveal any definite adenomas. The patient subsequently underwent bilateral adrenal venous sampling, which suggested a left-sided source of aldosterone excess. A repeat computed tomography of the adrenals with fine cuts revealed a 6-mm diameter adenoma of the left adrenal gland. He underwent an uncomplicated left adrenalectomy. All antihypertensive and potassium supplements were stopped on the 5th postoperative day. Two and half years after the adrenalectomy he remains normotensive and normokalaemic without any medication. The case illustrates the importance of measuring serum potassium before initiation of any therapy and the need to consider secondary causes even if a primary association is known. It also reinforces the fact that when hypertension becomes difficult to control, a secondary cause has to be searched actively. The association between primary aldosteronism and renal cysts has been highlighted only recently. The association of polycystic kidneys and primary aldosteronism has been reported in the literature only once previously.

Massive acute pulmonary embolism in protein S deficiency--a case report.

A young man with a history of deep vein thrombosis and pulmonary embolism 11 years ago presented again with acute pulmonary embolism and was treated initially with intravenous heparin at our institution. Five days later he had another massive bout of pulmonary embolism causing hypotension. Pulmonary angiography confirmed the presence of thrombi in both pulmonary arteries, with complete obstruction of the left pulmonary artery. He was treated successfully by emergency pulmonary embolectomy. Blood investigations later confirmed the diagnosis of protein S deficiency and he was started on warfarin therapy for life. Massive pulmonary embolism should be treated aggressively. Thrombolytic therapy accelerates clot lysis, reduces pulmonary pressures, restores pulmonary capillary volume and reverses right heart failure faster than heparin alone. There is also a trend towards decreased mortality with thrombolysis. In the presence of shock, the patient should be resuscitated and if facilities for emergency embolectomy are available, surgery is a viable alternative to thrombolysis, especially if the clot burden is massive. In young patients with recurrent venous thromboembolism in the absence of obvious predisposing factors, it is important to exclude inherited plasma protein deficiencies of protein S, protein C, antithrombin III, plasminogen and fibrinogen.

Echocardiographic detection of mobile right atrial thrombus.

Mobile right atrial thrombus is a rare echocardiographic diagnosis with important implications on further management. We report a case of 50-year-old woman with deep vein thrombosis of her left lower limb, who was found to have a large mobile serpiginous right atrial thrombus on both two-dimensional echocardiography (2DE) and transoesophageal echocardiography (TEE). She developed acute pulmonary embolism within thirty-six hours of diagnosis and subsequently underwent successful pulmonary embolectomy. This case demonstrates the usefulness of echocardiography as a non-invasive tool in the investigation of suspected pulmonary thromboembolism. The detection of right atrial thrombus mandates serious consideration for prompt surgical action.

Percutaneous transseptal balloon mitral valvotomy: initial experience in Singapore.

Between June 1990 and August 1991, 28 percutaneous transseptal balloon mitral valvotomy procedures were attempted in 27 patients (23 women and 4 men; mean age 39.8 +/- 9.3 years) with severe mitral stenosis. Successful mitral valvotomy was achieved in 25 patients (primary success rate of 92%). Mitral valve area increased from 0.82 +/- 0.17 cm2 to 1.53 +/- 0.48 cm2 (p < 0.001) and the mean mitral valve gradient decreased from 13.4 +/- 7.4 to 6.0 +/- 5.4 mmHg (p < 0.05). There were no deaths, one patient had cardiac tamponade after transseptal puncture and required emergency pericardiocentesis with successful percutaneous balloon valvotomy 6 months later. One patient had an unsuccessful valvotomy because the mitral valve could not be crossed and another patient had an inadequate dilatation. Our initial experience in percutaneous transseptal mitral valvotomy confirms the safety and efficacy of this new technique for the treatment of rheumatic mitral stenosis.