Digital Technology & Patient Assessment: Understanding DICOM Communication in the Wound Care Clinic

Establishing and maintaining effective collaboration and communication between hospital departments is an ongoing initiative for any healthcare system, especially when considering the push toward quality-based reimbursement. Historically, we have seen the delivery of chronic wound care become “siloed” from other departments across the continuum; however, as the Quality Payment Program and accountable care organizations have increasingly taken shape, we are seeing a shift in which the outpatient wound care department is recognized as a critical component to patients’ care planning. To that end, more wound care clinics are seeking access to digital devices and systems that enable more effective communication and collaboration internally, as well as throughout the continuum, in an attempt to better manage the treatment of chronic wounds and their associated comorbidities. 

The sophistication of today’s medical devices provides better clinical utility when they can be easily integrated into an institution’s workflow, such as through the utilization of DICOM (digital imaging and communications in medicine) technology, which allows devices to communicate with each other over a network by storing and transmitting medical images through multiple devices (eg, scanners, servers, printers). This article will discuss DICOM technology and how it can impact a wound clinic’s care planning and patient outcomes. By way of example, the authors will focus on one specific modality’s relationship to the assessment and treatment of peripheral arterial disease (PAD).

DICOM DETAILS

DICOM technology follows a protocol that enhances a medical device’s impact on patient care by sharing important communications, assessments, and results that are performed prior to patient testing and again following patient testing. Prior to patient testing, devices use a modality worklist (MWL) query to obtain information about patients who are scheduled for specific testing. Following that testing, devices use a storage request to save images and other test information to a picture archiving and communication system (PACS).

MWL queries are made to a DICOM worklist server, prior to a patient’s testing, where the patient demographic information usually originates from a radiology information system (RIS) or hospital information system (HIS). The DICOM’s worklist server communicates with the RIS/HIS using standards established by the Health Level Seven International (HL7), a not-for-profit, organization that’s accredited by the American National Standards Institute and tasked with providing a framework and standards for the exchange, integration, sharing, and retrieval of electronic health information that supports clinical practice and the management, delivery, and evaluation of health services. Information retrieved from a worklist server can be transferred to a device without the possibility of entry errors, which can save clinicians valuable time for attending to patient care as opposed to being inundated with entering information into the device. When patient testing is complete, DICOM devices can use a storage request to save images and other test information to a PACS or other storage server. Identifying information obtained from the worklist server will transfer to messages sent to the PACS, if the test was initiated from a patient scheduled by a DICOM worklist. (An example of identifying information is an accession number, which ensures a patient report is associated with the correct patient order.)

DIGITAL PAD SYSTEM & DICOM

The SensiLase PAD-IQ^® System (PAD-IQ; Väsamed, Eden Prairie, MN), a third-generation, transportable device that performs noninvasive vascular tests to help identify patients who are living with PAD and other alterations in circulation, is an example of a modality that supports communication by the DICOM standard. Information for scheduled patients is readily integrated into the device, enabling the clinician to quickly begin performing tests of skin perfusion pressure (SPP), pulse volume recording (PVR), and the ankle-brachial index (ABI). The SPP test measures skin perfusion using a laser Doppler sensor and a pressure cuff to evaluate reactive hyperemia. This type of provocative functional maneuver requires that the pressure cuff is first automatically inflated to occlude arterial bed blood flow; this is verified by the SensiLase PAD-IQ, which determines that perfusion has stopped. The pressure is then automatically released at a controlled rate while the cuff pressure and skin perfusion are measured. A graph then displays pressure and perfusion during cuff deflation and indicates the pressure at which skin perfusion is found to return. Additional information observable from the graph includes percentage perfusion increase above baseline, total response time, perfusion reappearance time, and perfusion contour. The PVR test measures and displays a waveform representing variations in the volume of blood passing through a limb during each cardiac cycle. The PVR test is fully automated and uses a partially inflated pressure cuff to apply slight pressure to the limb. The impact of blood passing through the limb is transferred to the pressure cuff, where it is measured as small changes in cuff pressure. The changes are displayed as a PVR waveform. The PAD-IQ can also be used to fill and empty pressure cuffs to assist in acquiring pressure values for calculating ABI, which can be useful in providing an indication of PAD, depending on the methodology and technology used to detect the return of arterial pressure following controlled occlusion and release of arterial flow. (Since the changes made in the 2011 Current Procedural Terminology code language specifically require independent assessment and documentation of the pressures at the dorsalis pedis, posterior tibial, and brachial arteries, PAD-IQ supports Doppler-based ABI systems only.) Test reports (see Figure above) can be transmitted to a PACS, negating the need to print or manually transfer files while making information available on the RIS/HIS of multiple healthcare sites. 

TESTING, TESTING PAD

The PAD device enables clinicians to quickly retrieve a list of patients scheduled for testing —  the most commonly referenced patient and study information is displayed in a worklist table. The clinician selects a patient from the table, information from the worklist automatically populates data fields of the interface, and the clinician can begin testing. Clinicians can sort the worklist table by several types of data, including patient names, scheduled date/time, and accession number. Clinicians can also view detailed patient information and manually enter supplemental info. The PAD device also provides diagnostic info in conjunction with worklist queries while displaying connection status as information is retrieved from the worklist server. A log file tracks connection status, which is useful to resolve issues if devices fail to communicate. 

When a patient’s test session is complete, a test report is generated by the PAD device. When DICOM storage is enabled, generation of the test report is followed by creation of a message for communication to the DICOM server. PAD-IQ then packages images of the test report with identifiers and other test information into the DICOM message. The PAD-IQ also creates a DICOM secondary capture image of information for transmission to the storage server. In this way, it is not necessary for clinicians to print paper reports or manually transfer report files to the RIS/HIS. Should technical difficulties arise, a connection between the PAD device and the storage server may not be available when the device generates the test report. In this situation, the device provides the ability to transmit reports at a later time, when the server is available. The PAD device supports DICOM modality worklists by providing a “patient worklist” screen. 

TECHNOLOGICAL SPECIFICATIONS

Administrators of DICOM devices can tailor those devices to “behave” in ways to best fit their environment, and this device supports network access by Ethernet and Wi-Fi, and can be connected by USB or Bluetooth. (Versions of the PAD device that were released prior to support for DICOM can be updated, usually by a remote connection to the device.) Setup of the PAD device involves assigning a unique name (DICOM title) to the device, which also supports multiple DICOM character sets and thus offers the capability of complementing the software’s clinician interface (available in multiple languages). The device also provides a means for DICOM administrators to add and configure multiple servers into the DICOM settings. The administrator can add a server, title, Internet Protocol address (or hostname), and port number for the server, then verify that responses are received from the server. The administrator can also add other servers and select which server will be used at present. 

The PAD device provides three screens for configuration of DICOM settings: “client” (to configure settings for the PAD device itself, “worklist” (to configure the way scheduled patients are queried from a worklist server), and “store” (to configure the way images and other information are transmitted to a PACS or other storage server). Multiple servers can be added for both the worklist and store sections. This feature is useful if a server is offline, making it easy to select a different server that is already configured. This feature is also useful if the device is transported between multiple sites. The device also provides quick access to the DICOM log. This feature is helpful for an administrator when troubleshooting a connection problem. Access to the DICOM log is supported on the setup screens for worklist servers and store servers. The PAD device also allows worklist queries to be restricted so that only pertinent schedule items appear on the patient’s worklist table. Worklist queries can be restricted to the particular device, can be restricted based on scheduled date, and can be restricted to a particular modality type. The administrator can apply any or all restrictions as is appropriate for that network. The PAD device also allows administrators to control which data are transmitted to the store server. The DICOM standard cannot foresee every piece of information that might be supplied by medical devices. For this reason, the DICOM standard provides a way for manufacturers to add “private” data elements. The PAD device uses this feature to place data for SPP and PVR tests into messages. Furthermore, the device allows administrators to exclude private data, which can be useful if the PACS is not able to receive this data.

Mike Schreiber is president and chief executive officer, and Dan Bartnik is chief technology officer/vice president of operations at Väsamed.