Twitter Updates

    follow me on Twitter

    15 April 2005

    Learning from ER: embolectomy for stroke

    Last night on ER: Season 11 Episode 15: Alone in a Crowd
    A young mother of three (Cynthia Nixon of Sex in the City) is brought in with symptoms of a potentially fatal stroke .....

    Its too late for thrombolysis but the interventional radiologist carries out an embolectomy using a new technique ...

    I'd not heard of this one before, so I turned to Google.
    Here's the result of one Google search.

    Thrombolysis nust be initiated within three hours of onset of an acute stroke, but embolectomy with the Merci retrieval system is effective up to 8 hours after onset of stroke symptoms.

    A description of the technique can be found here.
    For a video, click here.
    The vendor's site is here.


    Mechanical thrombectomy of the internal carotid artery and middle cerebral arteries for acute stroke by using the retriever device.
    Martinez H, Zoarski GH, Obuchowski AM, Stallmayer MJ, Papangelou A, Airan-Javia S
    AJNR Am J Neuroradiol. 2004 Nov-Dec;25(10):1812-5

    MERCI 1: a phase 1 study of Mechanical Embolus Removal in Cerebral Ischemia.
    Gobin YP, Starkman S, Duckwiler GR, Grobelny T, Kidwell CS, Jahan R, Pile-Spellman J, Segal A, Vinuela F, Saver JL.
    Stroke. 2004 Dec;35(12):2848-54. Epub 2004 Oct 28

    And a case report published in 2000 claiming to be 'the first reported use of a snare to remove clot in the setting of thromboembolic stroke'
    Transcatheter snare removal of acute middle cerebral artery thromboembolism: technical case report.
    Chopko BW, Kerber C, Wong W, Georgy B.
    Neurosurgery. 2000 Jun;46(6):1529-31

    Other things I've learnt from ER:

    Different ways of holding and positioning a Sonosite portable ultrasound machine.

    How to rule out a mandibular fracture and avoid doing an x-ray (get the patient to bite a tongue depressor, then twang it; if it doesn't hurt, there's no fracture).

    I'll be submitting my ER viewing for CME credits.

    10 April 2005

    Farewell to intravenous urography

    We've now stopped doing IVUs in my department!

    In place of IVUs, we do noncontrast CT for investigation of urinary stones, and CT urography, where indicated, for haematuria. (Indications for ultrasound are, for now, unchanged).

    CT urography is a better test, and more sensitive for detecting stones, urothelial lesions and tumours. The main drawback is radiation dose. However, for stone disease, the dose from a noncontrast CT can be brought to levels similar to that of an IVU using a low-dose technique. For patients with haematuria at high risk for cancer, many of them would have ended up with a CT anyway, and if not I think the extra dose is justified by improved diagnostic confidence and accuracy. As they say, if it was me or one of my relatives .....

    The technique is relatively simple, and it is easier to get consistent results than with a conventional IVU. It takes less time, and a morning's work in the IVU room can be completed in the CT scanner in about an hour. One extra radiographer has now been allocated to the CT scanner (in place of the one who used to do IVUs), which has helped to resolve some of our staffing problems. The radiographers are delighted because they didn't like doing IVUs. The urologists are pleased as well.

    Our CT urography protocol, on a Toshiba Aquilion 16, consists of a low dose noncontrast run to detect stones, followed by post-contrast imaging using a split blous technique which produces a combined nephrographic and excretory phase image. Imaging is done supine, and repeated in the prone position if ureteric opacification is inadequate.

    9 April 2005

    Whole-body CT screening

    A whole-body CT screening centre has been in operation at a town near mine, part of a chain called Lifescan. Patients pay between £300 (for a lung scan) and £750 (whole body CT with virtual colonoscopy) for CT scans to screen for unsuspected disease. Anything that is found that might possibly be significant then needs to be followed up. Sometimes early, unsuspected cancer is found . But often, the abnormalities turn out to be insignificant and of no consequence.

    This ends up being very expensive, and a team from the Massachusets General Hospital concluded that CT screening was not cost-effective.
    Cost-Effectiveness of Whole-Body CT Screening
    Beinfield, Wittenberg, Gazelle, Radiology 2005 Feb;234:415-422

    If the patient pays directly, this is not too much of a problem (at least for the health care providers), but medical insurers do not cover CT screening, and in many countries, the state ends up bearing the cost.

    Here is what others have said:

    Prof Adrian Dixon of Cambridge University, Warden of the Faculty of Clinical Radiology (the Royal College of Radiologists)
    Another topical issue is the question of walk-in screening centres offering to "save lives" by whole-body CT screening, sometimes for profit. In the UK, the National Screening Committee has suggested that the National Health Service should not offer such screening at present (Muir Gray, personal communication). Many sources suggest that a radiologist's private practice should mirror their NHS practice. The current radiological and radiographic workforce can barely cope with the existing workload, let alone such new ventures. It will be interesting to hear what other countries recommend. Several observers have noted that such walk-in centres are usually located in relation to educated health-conscious consumers who can afford such procedures! ....... Hard facts from primary research are urgently needed. But I cannot see too many grant giving bodies rushing to assess what is currently viewed as a somewhat opportunistic and entrepreneurial endeavour.
    Whole-body CT health screening.
    Dixon AK. Br J Radiol. 2004 May; 77(917):370-1

    A group from the Mayo Clinic
    CT screening for lung cancer offers the possibility of reducing mortality from lung cancer. Our preliminary results do not support this possibility and may raise concerns that false-positive results and overdiagnosis could actually result in more harm than good .....
    Our data do not suggest a mortality benefit; whether CT for lung cancer meets the criteria for an effective screening test remains to be proved .....
    Our preliminary mortality results should cause physicians to pause and reexamine their positions if they are performing routine CT screening outside of a clinical trial.
    CT Screening for Lung Cancer:Five-year Prospective Experience
    Swensen et al. Radiology 2005 April ;235:259-265.

    A group from Stanford (with regard to the situation in the United States)
    Direct-to-consumer marketing of self-referred imaging services, in both print advertisements and informational brochures, fails to provide prospective consumers with comprehensive balanced information vital to informed autonomous decision making. Professional guidelines and oversight for advertising and promotion of these services are needed.
    Advertising, Patient Decision Making, and Self-referral for Computed Tomographic and Magnetic Resonance Imaging
    Illes et al. Archives of Internal Medicine, December 13, 2004; 164(22): 2415 - 2419.