As little as one extra MRI per day can generate more than an additional $200,000 in incremental revenue annually, but most imaging centers use crude scheduling systems that do not accurately present a center’s potential throughput. David A. Dierolf, director of performance improvement, Outpatient Imaging Affiliates (OIA), Nashville, Tennessee, outlined a handy method for understanding the potential of your schedule to enable maximum throughput for an audience gathered in 2007 at the annual meeting of the RBMA in St Louis, Missouri.
Figure. Algorithm for calculating theoretical maximum throughput
Hired in advance of the DRA to improve efficiency, Dierolf, an IT expert, shared techniques that yielded significant additional incremental revenue at University of Virginia Imaging (UVI), Charlottesville, Virginia. A partnership between OIA and the University of Virginia, the center operates four very busy MRI scanners and is already working toward a fifth.
The center’s third available appointment was eight or nine days out in the fall of 2005. Dierolf was charged with developing methods to assess whether the scanners were running at maximum capability and when a new scanner should be purchased.
Because the scheduling system dated back to 1970, there was not a lot of flexibility. “Back then, we were scheduling everyone into 45-minute time slots,” Dierolf notes. “When scheduling, you looked at four different screens.”
Table. Expected Exams per Slot
Dierolf says, “We knew how many patients we saw and how many examinations we did, but we couldn’t figure out how many slots we did not use, to find out how many examinations we could do.”
Calculating Theoretical Maximum Throughput
Dierolf went to the logs of each machine and transferred technologists’ no-show and cancellation notes for two months to a spreadsheet to determine how many examinations he could get into each appointment slot. Because MRI of the brain and MR angiography (MRA) of the head could be performed in one 45-minute slot, for example, knowing the number of patients seen was not enough; two procedures sometimes took one slot, but sometimes two slots.
“Evaluating the procedure mix proved to be key, and this probably made it much easier to get this information for other modalities or other centers,” Dierolf explains. He recommends following this procedure to avoid going through appointment logs: First, identify sets of two examinations done during the same visit. Second, determine, for these sets, how many appointment slots are scheduled. Third, calculate how often those sets occur in a month.
For instance, set 1 (see table, page 19) was MRI of the abdomen plus MRA of the abdomen. Whenever that set occurred (78 times per month), Dierolf saved one appointment slot. He repeated that exercise for every examination set that the center performed. “Sometimes, as for MRI of the brain, MRA of the head, and MRA of the neck, three examinations fit two slots,” he explains. “Sometimes, I don’t save anything.” For example, MRI of the brain plus MRI of the cervical spine requires two slots.
Using one month’s data, Dierolf found that he performed 1,295 examinations, with a savings of 127 slots, that used 1,168 slots. He divided 1,295 by 1,168, to discover that he gets an average of 1.11 examinations for every appointment slot.
“The only way you are going to gain is if your schedulers know, anytime I’m doing a MRI of the brain and an MRA of the head, schedule that in one chunk. That’s an important efficiency gain,” Dierolf explains. “By doing the analysis, you know what common combinations you have, and this is a really important number: 1.11 examinations per slot. This is a good 10% to 11% savings, so if I am scheduling one examination per slot, I am off 10%, right from the beginning.”
When you know your expected examinations per slot, you can determine your maximum throughput figure (see figure). Dierolf cautions that this calculation is theoretical, not practical; center managers need to understand that this is a tool to gauge efficiency, not necessarily a realistic goal. In the case of UVI, which had 371 slots per scanner per week and the potential to do 1.11 examinations per time slot, managers should not necessarily expect staff to push through 411 examinations in a week.
Once he had a measure of efficiency, Dierolf turned his attention to a list of efficiency detractors that could decrease throughput. They are
- last-minute cancellations