worklist "no items found" question

[reinhardt]

I have installed a medison accuvix on a network and worklist server
connects, then performs a query and then comes up with a "no items
found" response with a "cancel" option.

any ideas on the possible connectivity/configuration problem?

thanks,

dk

[goodalle]

There are several different patterns or archeotype behaviors that
modalities vendors tend to use in their queries to modality worklists.
One model is for the modality to query for a single specific
procedure, often based on a technician entry or barcode scanning of a
procedure identifier. Another pattern is to query for and return
multiple entries for a specific patient, again performed based on
technician input, but resulting in a pick list that the technician
selects from. Still another approach is one where the modality issues
a "broad query" trying to find multiple entries that are likely to be
performed on the modality during some near term, but not neccessarily
immediate timeframe. The results of this query are cached on the
modality and maintained in a pick list that the technician can choose
from when initiating a new exam. It has been my experience that
ultrasound vendors tend to use this latter pattern for their worklist
scu implementation.

When querying a general worklist provider which serves a worklist for
all procedures performed in a department or even a whole facility, the
trick is providing a suffcient query keys such that the modality does
not receive an excessive list of procedures unlikely or impossible to
be performed on the querying device. A typical way this can be
accomplished is for the device to filter entries by the modality code
-- i.e specifying a value of "US" for (0008,0060) Modality on the
worklist to limit the entries to only those procedures identified as
ultrasound. Additional constraints may also be used such as limiting
the returned entries to only those procedures scheduled to be
performed within say 1 before the current time and 2 hours after the
current time. A tight filter might limit the returned entries to only
those procedures explicitly scheduled for the querying device's AE
Title (Scheduled State AE Title).

The accuvix dicom conformance statement found at
http://www.sonoace.de/pdf/accuvix%20xq_dcs_rev1-sdg.pdf
identifies a number attributes queried for/retrieved from a worklist
server

From the conformance statement, the device is apparently configured to
only search for entries with "US" as the modality type. It is unclear
whether they are configurable to query/filter by specific values, but
the conformance statement also shows the device can query for
scheduled ae title (0040,001), Scheduled Start Date (0040,0002) and
Scheduled Start Time (0004,0003) start time.

It can be useful to query for these attributes to prevent too many or
inappropriate exam entries from being downloaded and presented on the
ultrasound device pick list, but they can also overly constrain a
query so no results are returned. For example, if the modality is
configured to only query the worklist for it's own AE Title in
(0040,0001) - Scheduled Station AE Title, AND the worklist provider
doesn't schedule procedures to a specific device, then the modality
will not receive any results. Again, in my experience, ultrasound
departments often have multiple devices with different AE Titles, all
of which can perform any of the ultrasound procedures performed in the
department. In these cases, patients are typically queue and assigned
a device/station on a first available basis. Thus, it would be
counterproductive for worklist provider to assign a specific Scheduled
AE Title to entries on the worklist.

In diagnosing the problem of why you're not getting anything returned
to the modality, there are two things you need to know: First,. what
query or filter tags is the modality using? Second what values is the
worklist provider populating the entries on the worklist with -- are
they being populated with appropriate values? For example, I've seen
cases where worklist SCPs were setup to populate all entries with
modality code "CR" unless explicitly overridden. You know already that
the accuvix is only looking for entries with modality code "US". So
first check is to query the worklist with a query client and determine
whether there are any entries on the worklist with modality code US.
Basically - you have to work it from both directions - what is
modality filtering on? Is it excluding procedures it should be seeing
due to overly constrained query parameters. What is the worklist
provider populating entries with? Are the values appropriate so the
accuvix should be able to distinguish the appropriate procedures and
filter the inappropriate ones.