NEC Thermography Infrared Imaging Study
Condition: Necrotizing Enterocolitis
MeSH terms: Enterocolitis; Enterocolitis, Necrotizing
Study type: Observational

Summary: 
      Necrotizing enterocolitis (NEC) is a devastating disease affecting the intestines of
      premature infants. It involves intestine swelling, tissue destruction, infection, and even
      death. Improved outcome is highly dependent on early recognition and treatment, however the
      signs and symptoms of NEC in early stages are not obvious making it difficult to diagnose.
      Abdominal x-rays and ultrasound can be non-specific and may not show signs of the disease
      until late in its course.

      Infrared imaging is a non-invasive, non-radiation method that can measure the heat given off
      of the surface of the body and create heat maps. It is being used clinically in other
      situations but is still under investigation for use in preterm infants with suspected NEC.
      Computer analysis of the measured heat maps can be used to detect changes in the intestine
      such as the swelling or tissue destruction involved in NEC.

      Our group has previously performed a pilot study that showed that infrared imaging on babies
      in the NICU can be used to create heat maps that are different between normal babies and
      those with NEC when analyzed using specialized computer programs. In this study the
      investigators will improve the imaging process by using special vision sensors to automate
      the imaging process and make it easier for bedside staff to use this technology. Special
      programs will be developed to automatically select areas of interest over which temperature
      maps will be analyzed. The investigators will use this new imaging technique to study a
      population of newborns diagnosed with definitive NEC and a healthy population of newborns
      without NEC, and compare the heat maps obtained from each group. From the analysis of the
      images obtained from these two populations, the investigators will determine the suitability
      and necessary fine-tuning of this new imaging technique with the hopes that this technology
      can someday aid in the early diagnosis of NEC.
    

Detailed description: 
      Background information about NEC:

      The best prognosis requires early recognition and treatment of NEC. Perforation or ongoing
      deterioration may require surgical intervention. Mortality has improved in recent years but
      is still about 15-30 % for non-surgical NEC and up to 50% for surgical NEC. Survivors may
      suffer significant complications including long-term damage to bowel function.

      The initial diagnosis is based on clinical exam and diagnostic imaging, usually involving
      abdominal x-rays +/- ultrasound. Bell's staging criteria incorporates clinical, laboratory,
      and radiographic findings, and is used to discern suspected NEC from definitive NEC. Bell's
      stage 2 denotes proven NEC and involves the presence of pneumatosis intestinalis and/or
      portal venous gas on x-ray.

      The main difficulty when diagnosing NEC is that early/suspected stages of NEC present
      clinically and radiographically in a similar way to benign feeding intolerance seen with
      prematurity. Abdominal x-rays involve exposure of the patient to ionizing radiation and
      ultrasound imaging is disruptive to the patient, takes time to perform, and requires skilled
      operators who have limited availability. These modalities will only show non-specific changes
      in early stages of NEC. Late findings are more discerning, however by the time these findings
      are apparent the optimal time frame to initiate treatment is often missed.

      Background Information About Medical Thermography:

      Medical infrared (IR) imaging is a combination of medical technology, infrared camera
      technology and computer multimedia technology. Infrared imaging devices record the human
      thermal fields. The human body is a natural biological heating source and an infrared thermal
      imager converts the far-infrared light wave radiated by the human body to an electrical
      signal which is then converted into a digital quantity by analog/digital conversion. The
      signals are processed by multimedia image processing technology into a color heat map,
      showing the body's temperature field. A normal, healthy body has a characteristic heat map
      while an abnormal body exhibits deviations from this heat map. Thus, comparing the
      similarities and differences between the two, in combination with clinical diagnosis, doctors
      and researchers can infer the nature and extent of a disease.

      The investigators investigated various methods of computerized assessment of thermal images
      obtained from premature babies with definitive NEC compared with normal babies with no
      symptoms of feeding intolerance. The investigators showed that the discriminating power of
      the surface temperature evolution data between healthy control babies and those who were
      diagnosed with NEC was promising, with fairly high classification rate and a simple linear
      classification scheme. In addition, our results suggested a slower rate of decrease of
      abdominal skin temperature in the NEC babies, which might be explained by the presence of
      inflamed bowel. Rice et al. also used medical thermography to help detect NEC in newborn
      infants admitted to the NICU. By comparing temperature distribution over abdominal segments
      to those of the chest, they were able to determine differences in normal babies vs those
      diagnosed with NEC.

      Background Information About Medical Microsoft Kinect Sensor:

      The Kinect sensor is a widely used, consumer-grade, and safe color and depth camera
      commercially marketed for use in computer gaming. It measures near infrared light reflected
      off the body to form a surface map of the environment. The RGB-D Kinect sensor has recently
      been applied to healthcare in a variety of applications where it has shown to be effective,
      including the field of medical rehabilitation, where Kinect sensors are used for active
      exercise training and rehabilitation of patients,for safe and automated radiotherapy
      delivery, for chest wall motion analysis in cystic fibrosis patients, for facial feature
      analysis of posture control in rehabilitation patients, in ICU patients for automated
      mobility measurements, and even automated apnea monitoring in infants and children.

      In this study, the RGB-D Kinect sensor's role will essentially consist of supporting the
      automated segmentation, and retrieval of thermal distribution data from the co-located and
      calibrated IR FLIR imager. Thanks to the color and depth maps that will be made available,
      classical and robust image processing techniques will be leveraged to identify regions of
      interest (the baby's body and eventually abdomen). This sort of precise segmentation cannot
      be reliably performed solely from IR images, as it is well established that computer vision
      and image processing techniques are not well adapted for IR images. Early laboratory tests
      have already been conducted to determine that the operation of the RGB-D sensor in an
      overlapping field of view with that of the IR imager does not influence the data collected in
      the heat map. The combined operation is therefore safe and will provide an accurate thermal
      distribution as if the IR imager was operating alone. The end goal is to combine the
      strengths of three imaging technologies to improve medical diagnosis.

      Study Rationale:

      Previous studies investigating thermography and diagnosing NEC only used an infrared camera
      to acquire images. Although the investigators were able to derive thermal distributions for
      babies of various GA's, our previous study did not adopt a strict protocol for positioning
      the IR sensor in an optimal configuration, leading to more variations in image quality and
      size of region of interest. These limitations made it difficult to automate the selection of
      accurate regions of interest within the thermal image and required manual intervention from
      an image processing expert. In our current study the image acquisition process will be
      improved upon and standardized; a Microsoft Kinect sensor utilizing thermal, color and active
      depth vision will be integrated into a thermographic camera to allow for automated selection
      of regions of interest and will facilitate ease of use by medical personal at the patient's
      bedside. Embedded image processing algorithms will be developed to exploit the multi-spectral
      nature of collected information in order to automatically segment and unclutter the region of
      interest over which thermal distributions of relevance will be monitored.

      Initial development of this system, including apparatus integration and assembly, rigorous
      camera calibration procedures in between the RGB-D and IR sensors, and complete testing will
      be performed in a laboratory environment, using only mock-up models of the clinical
      environment. Then, in order to fully validate the application of this automated infrared
      image processing system for early diagnosis of NEC, acquisition of relevant images from human
      subjects is needed. The study will be pursued in the NICU environment to further validate the
      newly developed non-invasive and automated imaging protocol on babies of various sizes and GA
      in the NICU, since NEC can occur in babies ranging from extremely premature to those born at
      term. Since the investigators hope to use this technology someday to help improve the
      diagnosis of NEC, the experimental imaging procedure will be performed on two patient
      populations. The investigators will first image the abdomens of a group of healthy newborns
      with the newly developed apparatus and image processing protocol to set up a standard thermal
      distribution. Then, the investigators will also image the abdomens of a group of newborns
      with proven NEC, using the same equipment. From the analysis of images from these two
      populations, the investigators will determine the suitability and necessary fine-tuning of
      the proposed automated infrared imaging tools, with the objective of augmenting the
      precision, usability, and reliability of the procedure for early diagnosis of NEC.

      Objectives:

        1. Develop an automated approach to the imaging and analysis of preterm infants' abdomens
           using thermographic sensors and embedded image processing algorithms.

        2. Derive thermographic temperature distributions of the abdomens of two groups of babies:
           those who are normal (have no signs of feeding intolerance or signs of NEC), and those
           who have been diagnosed with proven NEC.

        3. Determine if the automated image processing algorithms can discern a statistically
           significant difference between the normal thermal distributions and those derived from
           babies with NEC.
    

Intervention name(s): A FLIR Thermovision a320M thermal IR camera
Intervention type(s): Diagnostic Test
Intervention description(s): Clothing removed if necessary
ECG leads, temperature probes, or transcutaneous monitors will be relocated for abdominal imaging.
Axillary temperature prior to starting the thermographic imaging.
Baby's mattress slid out of the isolette and warming bed will be turned off for no more than 60 seconds. This step is necessary since infrared radiation does not pass through the Plexiglas walls of an isolette and the infant's skin surface needs to cool off slightly.
After surface cooling, thermal imaging will be recorded for ~60 sec to allow for the infrared radiation naturally emitted by the subject's body to be recorded by the infrared camera. The timestamp corresponding to the removal of the heat source will be noted, to indicate the start of the cooling of the abdomen.
After ~60 seconds of image recording, the recording will stop, the mattress pushed back into isolette.
Axillary temperature to ensure temperature stability, any clothes will be put back on.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Neonates admitted to the NICU at CHEO or TOH-GC
      
Keywords: Neonates; Thermography imaging