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Incrementally optimizing scanner utilization

Case Study
Retzlaff, Sebastian, Dr.

Incrementally optimizing scanner utilization

The Practice for Magnetic Resonance Imaging (Schwerin, Germany) has been using an Achieva 1.5T since 2004. Though the diagnostic quality justifies the investment, the economic return is important too. This requires a carefully coordinated and intensive examination schedule to ensure the best possible utilization. The dependable appointment planning satisfies both patient and staff expectations.

The two radiologists and four radiographers in the practice handle examination types from neuro and musculoskeletal, through body, to cardiac examinations. Ten thousand examinations a year translate to just over 50 patients a day. Sebastian Retzlaff, M.D., founder of the practice, has fine-tuned examination procedures so the practice can handle up to 60 examinations a day. In combination with slightly longer hours on Wednesdays and Fridays, this is enough to make up for any temporary backlogs that may occur, without having to work weekends.


Even under normal circumstances, patient throughput is high. "Scanning many patients a day requires short examination times," explains Dr. Retzlaff, "And short examination times also have the advantage of greater convenience for patients and fewer gross motion artifacts. The patient appreciates this too." Streamlined scan protocols and optimized patient logistics are key, but Dr. Retzlaff emphasizes that efficiency should never mean compromising image quality. "We not only strive to work faster, we also want to work better," he adds.

 Dr. Retzlaff:  The Practice for Magnetic Resonance Imaging in Schwerin, Germany.
Dr. Retzlaff: "The practice improves one sequence every day. If the sequence proves its worth in 20 patients, it replaces the original in the ExamCard. The radiologist judges the effect of parameter adjustment on diagnostic confidence."
The Practice for Magnetic Resonance Imaging in Schwerin, Germany.

Daily incremental improvements to reach target examination times

A fundamental principle is to improve one sequence every day, by shortening the examination time, improving the image quality, or both. If the sequence proves its worth, it replaces the original in the ExamCard, and Dr. Retzlaff sees how he can apply what he has learned further. For example, an improved sequence for the knee can often also be beneficial for shoulder examinations.


The second fundamental principle is to have no sequence with a scan time longer than two minutes. "Because of the interactions of the various scan parameters, this takes detailed work," he says. Only the radiologist can fully judge the effect of parameter adjustment on diagnostic confidence. For example, for sagittal knee examinations, he reduced slice thickness from 3 mm to 2 mm. This improved spatial resolution, most noticeably in the improved representation of trabeculae. By adjusting other parameters, they could maintain the signal-to-noise ratio without increasing the measurement time.


A key feature for keeping sequences short is to use SENSE with multi-channel coils. "The most expensive coils are the best," says Dr. Retzlaff. "But they really are worth it." For example, the center uses the SENSE Cardiac coil for examinations of large knees and shoulders, hips, sacral ilial joints, and the mediastinum, as well as the heart. "The SENSE Cardiac coil enables high SENSE factors to reduce scan time, combined with an impressive signal-to-noise ratio," says Dr. Retzlaff.


Because these coils already provide a good signal-to-noise ratio, the number of signal averages (NSA), can often be reduced to 1. Similarly, Dr. Retzlaff suggests experimenting with the NSA of reference scans, to see if these can be reduced without adversely affecting the phase correction.

Dedicated ExamCards for different patient types

Ordering sequences correctly in an ExamCard also offers potentials for saving time. For example, running sequences with long reconstruction times at the end; the radiographer can start helping the patient out of the MR room while the scan is being reconstructed.


To make setting up easier and faster, the center has built an extensive set of dedicated ExamCards - for example for small, medium and large patients, or for patients who have difficulty holding their breath. By having most of the parameter settings ready in advance, the radiographers save preparation time. To avoid confusion or complications, the same protocols are used for both radiologists, and for all referring doctors. "There is only one optimum," says Dr. Retzlaff. "All our patients get the same, good images."

Streamlined patient handling

"Although the scan sequences and ExamCards are the easiest to standardize, patient handling is the decisive factor," stresses Dr. Retzlaff. This means minimizing the time a patient spends in the scanner room, by performing patient preparation and aftercare in or around the dressing room.


Having various positioning materials available is also important in ensuring positioning that is as efficient as it is effective. Dr. Retzlaff points out the importance of not making false savings on accessories that can make a real difference. Two radiographers work in parallel for examinations requiring contrast agents, because this takes intensive patient interaction. The radiographer positions the catheter with a Heidelberger extension beside the dressing room while the previous patient is still being scanned. As soon as the scanner room is free, the radiographer positions the patient, and starts the survey scans with the green button in the examination room. Before leaving, the radiographer connects the patient tubing to the pump (the pump's tubing is only attached once for each block of examinations). The ExamCard runs the sequences without contrast first, then stops to let the radiographer start the pump, typically during a T2 TSE or T2 TSE fat suppressed sequence. The sequences that need contrast agent run immediately afterwards.


During the last sequence, the radiographer disconnects the tubing from the pump and knots it. Outside the examination room, the radiographer removes the tubing and catheter.

Punctual and flexible planning

Examinations are, of course, grouped in blocks. For example, with all the shoulder examinations done in a block, the radiographer only needs to get and prepare the Shoulder coil once. The radiographers phone the patients the day before to remind them of their appointment.


For every second patient that cannot be contacted, an appointment is made from the waiting list as experience has shown that half of the patients may have been on another call, or temporarily away from the phone, and still make it.


To minimize the effect of cancellations, no shows or examinations that have to be abandoned (such as for patients with claustrophobia), a shortlist is kept of patients who live or work nearby and who can be called in at short notice.


Obviously, the commitment of the radiographers is key to any efficiency improvement. "You have to have good, motivated people," says Dr. Retzlaff. Their work is undoubtedly intensive, but because the procedures are well defined, there are fewer surprises. The radiographers can be fairly sure of finishing work punctually.


Though there are always unforeseen events, appointments can be planned with a high degree of confidence, so patients rarely have to wait for long. This increases their satisfaction, and reduces stress levels for everybody.


Saving ever more time

In summer 2007, the practice started using the second release of the software, which has also meant they could start working with 16-channel technology, and in particular 16-channel SENSE NeuroVascular and SENSE Body coils. The new software enables asymmetric TSE sequences, which further reduce examination times while improving contrast and resolution. The high sensitivity and high SENSE factors of the new coils save additional measurement time. "This is a real boost to our efficiency," says Dr. Retzlaff, "which helps us work faster and better." SmartExam is also part of the upgrade, enabling automated planning, scanning and processing, and providing further potential for increased efficiency.


Although he is not yet actively using the Philips Utilization Services that are now available, he is interested to see how much inactive and non-scanning time there still is to possibly optimize. He also recommends other centers use such reports, analyses and consultancy to pinpoint, quantify and track areas for improvement.


Looking back at images from the previous Intera 1.0T system, Dr. Retzlaff concludes that "By using the full capabilities of the stronger field and the SENSE coils, the image quality has doubled and the sequences today take half as long." Quality is an important part of radiologists' satisfaction in their work, but the investment in top-class equipment must also make economic sense. Though it takes time and effort every day, continual incremental improvements in the efficiency and effectiveness of the practice not only ensure the best return on the investment but, by maintaining the best possible level of service for patients and their referring physicians, they are an important competitive advantage.

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Jul 15, 2008

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Case Study
Achieva 1.5T
Release 1, Release 2, Release 2.5
operational efficiency, workflow

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