PubMed Health⌕ Search

Biomedical subjects

Rathan M Subramaniam

Publications and source records attributed to Rathan M Subramaniam.

9 recordsLinked to original sources
PubMed2006

Diagnosis of lower limb deep venous thrombosis in emergency department patients: performance of Hamilton and modified Wells scores.

STUDY OBJECTIVE: We validate and compare the Hamilton score for assessment of lower limb deep venous thrombosis with the modified Wells score. METHODS: Consecutive patients presenting to the emergency department of a tertiary center for suspected lower limb deep venous thrombosis were prospectively recruited. Hamilton score and modified Wells score calculations, D-dimer, and complete (calf veins included), single lower limb ultrasonographic examination were performed for all patients. All patients with a negative ultrasonographic examination result for deep venous thrombosis were followed up for 3 months. RESULTS: The study population consisted of 116 men and 193 women, with an average age of 55.6 years (SD 20.1). A total of 67 (21.7%) patients were diagnosed with deep venous thrombosis. Forty (59.7%) of these patients had isolated calf deep venous thrombosis, and the other 27 (40.3%) patients had proximal deep venous thrombosis. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) for an unlikely Hamilton score (score < or = 2) and D-dimer were 99% (95% confidence interval [CI] 92% to 99.96%), 42 % (95% CI 36% to 49%), 32% (95% CI 26% to 39%), 99% (95% CI 95% to 99.98%), 1.7 (95% CI 1.52% to 1.9%), and 0.04 (95% CI 0.01 to 0.25), respectively. The sensitivity, specificity, PPV, NPV, LR+ and LR- for an unlikely modified Wells score (score < or = 1) and D-dimer were 99% (95% CI 92% to 99.96%), 33 % (95% CI 27% to 39%), 29% (95% CI 23% to 35%), 99% (95% CI 93% to 99.97%), 1.47 (95% CI 1.34 to 1.62), and 0.05 (95% CI 0.01 to 0.32), respectively. CONCLUSION: An unlikely probability of Hamilton score and a negative D-dimer may effectively exclude a lower limb deep venous thrombosis. Hamilton and modified Wells scores have similar performance characteristics.

Data Collection↗
PubMed2006

Radiology curriculum topics for medical students: students' perspectives.

RATIONALE AND OBJECTIVE: We sought to establish medical students' perspectives of a set of curriculum topics for radiology teaching. MATERIALS AND METHODS: A multicenter study was conducted in New Zealand. A modified Delphi method was adopted. Students enrolled in two New Zealand Universities received a questionnaire. Each learning topic was graded on a scale of 1 (very strongly disagree) to 6 (very strongly agree). Students could also put forward and grade suggestions that were not on the questionnaire. RESULTS: Of 200 questionnaires, 107 were returned. Fifty male and 57 female students participated, with an average age of 23.7 years. The five highest ranking curriculum topics in order of importance were developing a system for viewing chest radiographs (5.77, SD 0.7), developing a system for viewing abdominal radiographs (5.66, SD 0.8), developing a system for viewing bone and joint radiographs (5.56, SD 0.8), distinguishing normal structures from abnormal in chest and abdominal radiographs (5.38, SD 0.9), and identifying gross bone or joint abnormalities in skeletal radiographs (5.29, SD 0.9). CONCLUSION: Medical students want to know how to look at radiographs, how to distinguish normal from abnormal, and how to identify gross abnormalities.

Adult↗
PubMed2006

Importance of pretest probability score and D-dimer assay before sonography for lower limb deep venous thrombosis.

OBJECTIVE: The purpose of our study was to develop and validate a clinical score (the Hamilton score) for the assessment of lower limb deep venous thrombosis (DVT) and to determine the usefulness of this score and a D-dimer assay before a complete lower limb sonographic examination. SUBJECTS AND METHODS: Five hundred forty-two consecutive ambulatory patients presenting to the emergency department were prospectively recruited, of whom 16 patients were excluded from the study. Eighteen history and examination variables were collected by the emergency department physicians. The Simplify D-dimer assay and a complete, single lower limb sonographic examination were performed in all patients. All patients with a negative sonographic examination for DVT were followed up for 3 months, and all those with a positive sonographic examination were given anticoagulation therapy. The Hamilton score was developed using the data from the first 214 patients and was prospectively validated in the next 312 patients. RESULTS: The most significant factors associated with a diagnosis of DVT were immobilization of the lower limb, active malignancy, and a strong clinical suspicion of DVT without other diagnostic possibilities by the emergency department physicians. Other factors were bed rest or recent surgery, male sex, calf circumference difference greater than 3 cm, and erythema. The Hamilton score was developed with the following weights: immobilization of the lower limb (2 points), active malignancy (2 points), strong clinical suspicion of DVT without other diagnostic possibilities by the emergency physicians (2 points), bed rest or recent surgery (1 point), male sex (1 point), calf circumference difference greater than 3 cm (1 point), and erythema (1 point). A score of 3 or greater indicates a likely probability for DVT, and a score of 2 or less represents an unlikely probability for DVT. Of the 103 patients with an unlikely probability Hamilton score and a negative D-dimer assay, only one patient had isolated calf DVT. A combined diagnostic strategy of unlikely-probability Hamilton score and a negative D-dimer would have a negative predictive value of 99% (95% confidence interval, 94.7-100%). CONCLUSION: An unlikely-probability Hamilton score and a negative Simplify D-dimer assay effectively exclude lower limb DVT, and a sonographic examination is unnecessary in this group of ambulatory emergency department patients.

Adolescent↗
PubMed2005

Deep venous thrombosis: withholding anticoagulation therapy after negative complete lower limb US findings.

PURPOSE: To establish the safety of withholding anticoagulation therapy after negative findings at a complete lower limb ultrasonographic (US) examination of the symptomatic leg for suspected deep venous thrombosis (DVT). MATERIALS AND METHODS: Regional ethics committee approval and patient consent were obtained. A total of 542 consecutive ambulatory patients presented to the emergency department and were prospectively recruited from April 2001 to May 2003. Of these patients, 16 were excluded, and radiology residents and sonographers performed a complete lower limb US examination by means of compression and Doppler US in 526 patients. Patients with negative US findings received no anticoagulation therapy, and they were observed for occurrence of any thromboembolic event for 3 months. Patients with progressive or new symptoms that were indicative of thromboembolism within the follow-up period underwent objective testing with US, computed tomographic (CT) pulmonary angiography, or both. RESULTS: There were 413 patients (78.5%) with US findings that were negative for DVT and 113 patients (21.5%) with findings that were positive. There were 64 patients (56.6%) with DVT isolated to the calf and 49 (43.4%) with proximal DVT. Of the 413 patients with negative initial US findings, 16 (3.9%) underwent a second US examination for new or progressive symptoms of DVT, one patient (0.25%) underwent CT pulmonary angiography for suspected pulmonary embolism, and one patient (0.25%) underwent both US and CT pulmonary angiography during the 3-month follow-up period. One of these patients (0.24%; 95% confidence interval: 0.01%, 1.3%) developed pulmonary embolism, which was diagnosed with CT pulmonary angiography. DVT was not diagnosed in any patient, and no patient died during follow-up. The negative predictive value of a complete single lower limb US examination to exclude clinically important DVT is 99.6% (95% confidence interval: 98.4%, 99.9%). CONCLUSION: A single negative complete lower limb US examination is sufficient to exclude clinically important DVT, and it is safe to withhold anticoagulation therapy after negative complete lower limb US findings were obtained in patients suspected of having symptomatic lower limb DVT. New or progressive symptoms require further objective imaging.

Angiography↗
PubMed2004

Transverse sinus septum: a new aetiology of idiopathic intracranial hypertension?

A venographic cryptic stenosis at the junction of middle and lateral third of the transverse sinus has been observed in patients suffering from idiopathic intracranial hypertension. After reviewing the anatomical and embryological literature of the transverse sinus, 20 transverse sinuses were explored (in a pilot study of 10 human cadavers) in order to determine the anatomical basis of this stenosis. The presence of septa of varying sizes was observed. We conclude that the presence of a large septum is one of the causes of venographic cryptic stenosis observed in these patients and might be one of the aetiological factors involved in idiopathic intracranial hypertension.

Cadaver↗
PubMed2003

Medical student radiology training: what are the objectives for contemporary medical practice?

RATIONALE AND OBJECTIVES: The authors attempt to provide a set of objectives for medical student training in radiology for contemporary medical practice. MATERIALS AND METHODS: A questionnaire containing a list of educational objectives was sent to 32 radiologists in charge of medical student training in radiology at accredited residency programs in Australia and New Zealand. The importance of including each preselected objective in the curriculum was measured by respondents' agreement or disagreement on a scale of 1-6. Opportunity also was given to respondents to suggest objectives other than those presented on the questionnaire. RESULTS: Twenty of the 32 questionnaires were returned, and a set of educational objectives was established based on the responses. The objectives were ranked in importance according to the mean score assigned to each objective by the respondents. CONCLUSION: This new set of educational objectives for medical student radiology training reflects recent changes in radiologic and medical practice and points to potential future developments.

Curriculum↗
PubMed2002

High-pressure water injection injury: emergency presentation and management.

Presentations of high-pressure water blaster injuries to the emergency department are varied. Though these injuries are sometimes described as a 'benign variant' of high-pressure injection injuries, external appearances can be deceptive. These injuries can produce an unexpected pattern of severe internal injury and infectious complications. Such injuries are surgical emergencies and must be evaluated quickly and thoroughly in the emergency department. We review the current literature of these injuries and present the first reported case involving a forearm injury.

Accidents, Occupational↗
PubMedDate not supplied

Does an immunochromatographic D-dimer exclude acute lower limb deep venous thrombosis?

BACKGROUND: A pre-test probability score and D-dimer may reduce the need for ultrasound examinations for excluding lower limb deep venous thrombosis (DVT). OBJECTIVE: To establish the accuracy of an immunochromatographic D-dimer assay called 'Simplify' for diagnosis of acute DVT by complete (calf veins included) lower limb ultrasound examination. METHODS: A total of 453 consecutive patients presented to the ED of a tertiary centre with suspected first episode of DVT, were prospectively recruited. A pre-test probability score (Hamilton Score), an immunochromatographic D-dimer and a complete, single, unilateral lower limb ultrasound examination were performed in all patients. All patients with a negative ultrasound examination were followed up for 3 months. RESULTS: There were 159 men and 294 women with a mean age of 55.8 years (SD 20.3). Of the 227 patients with a negative D-dimer, 214 patients had negative ultrasound examinations and 13 patients had isolated calf DVT. Among the 226 patients with a positive D-dimer, 74 patients had DVT and 152 patients had negative ultrasound examinations. The sensitivity, specificity, positive and negative predictive values were 85.1% (75.8-91.8), 58.5% (53.4-63.5), 32.7% (26.6-38.9) and 94.3% (90.4-96.9), respectively. One hundred and sixty-five patients had an unlikely Hamilton Score and a negative D-dimer. The negative predictive value of the immunochromatographic D-dimer in an unlikely Hamilton Score population was 98.8% (95.7-99.8%). CONCLUSION: An unlikely probability Hamilton Score and a negative immunochromatographic D-dimer reliably exclude both proximal and isolated calf DVT.

Adult↗