Study done by:

Department of Colorectal Surgery

Wilford Hall Medical Center, San Antonio, Texas, USA.

Brooks JP, Perry WB, Putnam AT, Karulf RE

Dis Colon Rectum 2000 Sep;43(9):1319-21

PURPOSE: The aim of this study was to introduce thermal imaging in the intraoperative detection of bowel ischemia by comparing thermal imaging with conventional techniques in detecting acutely ischemic bowel, using histologic evidence for intestinal necrosis as the standard.

METHODS: A prospective study was performed using a porcine model. Laparotomy was performed on four pigs under general anesthesia. A 25-cm segment of mid jejunum was tagged with proximal and distal sutures, and its mesentery was ligated and divided. Thermal imaging, visual inspection, Doppler ultrasound, and fluorescence with Wood's lamp after fluorescein were used to estimate the extent of bowel ischemia five minutes after ligation of the mesentery. Measurements were taken in reference to both the proximal and distal tags to obtain two data points per animal for each method. After two hours of warm ischemia, the jejunum was harvested and sectioned longitudinally. Comparisons were made between the estimated region of necrosis for each method and microscopic evidence of necrosis.

RESULTS: Visual inspection was the only method unable to detect a difference between vascularized and devascularized bowel for each of the eight data points. Fluorescein dye missed 3 cm of ischemic bowel. Doppler ultrasound and thermal imaging were 100 percent sensitive for necrotic bowel, with thermal imaging overestimating necrosis to a greater extent than Doppler ultrasound. The positive predictive value of fluorescein dye, Doppler ultrasound, and thermal imaging for determining nonviable bowel was 91.8, 80.8, and 69.5 percent, respectively.

CONCLUSIONS: Thermal imaging has the potential to be a useful adjunct in the intraoperative determination of bowel ischemia. Further studies are indicated to study this technique.

Study done by:

Department of Neurosurgery

Yongdong Severance Hospital, Yonsei College of Medicine, Seoul, Korea

Zhang HY, Kim YS, Cho YE

Yonsei Med J 1999 Oct;40(5):401-12

Subjective symptoms of a cool or warm sensation in the arm could be shown objectively by using of thermography with the detection of thermal change in the case of radiculopathy, including cervical disc herniation (CDH). However, the precise location of each thermal change at CDH has not been established in humans. This study used digital infrared thermographic imaging (DITI) for 50 controls and 115 CDH patients, analyzed the data statistically with t-test, and defined the areas of thermatomal change in CDH C3/4, C4/5, C5/6, C6/7 and C7/T1. The temperature of the upper trunk and upper extremities of the control group ranged from 29.8 degrees C to 32.8 degrees C. The minimal abnormal thermal difference in the right and left upper extremities ranged from 0.1 degree C to 0.3 degree C in 99% confidence interval. If delta T was more than 0.1 degree C, the anterior middle shoulder sector was considered abnormal (p < 0.01). If delta T was more than 0.3 degree C, the medial upper aspect of the forearm and dorsal aspect of the arm, some areas of the palm and anterior part of the fourth finger, and their opposite side sectors and all dorsal aspects of fingers were considered abnormal (p < 0.01). Other areas except those mentioned above were considered abnormal if delta T was more than 0.2 degree C (p < 0.01). In p < 0.05, thermal change in CDH C3/4 included the posterior upper back and shoulder and the anterior shoulder. Thermal change in CDH C4/5 included the middle and lateral aspect of the triceps muscle, proximal radial region, the posterior medial aspect of the forearm and distal lateral forearm. Thermal change in CDH C5/6 included the anterior aspects of the thenar, thumb and second finger and the anterior aspects of the radial region and posterior aspects of the pararadial region. Thermal change in CDH C6/7 included the posterior aspect of the ulnar and palmar region and the anterior aspects of the ulnar region and some fingers. Thermal change in CDH C7/T1 included the scapula and posterior medial aspect of the arm and the anterior medial aspect of the arm. The areas of thermal change in each CDH included wider sensory dermatome and sympathetic dermatome There was a statistically significant change of temperature in the areas of thermal change in all CDH patients. In conclusion, the areas of thermal change in CDH can be helpful in diagnosing the level of disc protrusion and in detecting the symptomatic level in multiple CDH patients.