Shinshu Med J, 72⑷：219～225, 2024

Impact of High-spec Infrared Video Camera for Intraoperative Evaluationof Kidney Graft Perfusion during Living Donor Kidney Tansplantation :A Pilot Study
Manabu Ueno, Tomonori Minagawa＊, Tomonori Kurita, Yoshihiro Inoue
Masashi Shiozaki, Noriyuki Ogawa, Hiroaki Hara and Teruyuki Ogawa
Department of Urology, Shinshu University School of Medicine

Background : Good kidney graft perfusion (KGP) is extremely important in kidney transplantation, although themethodology to evaluate intraoperative KGP has not yet been established. The present study tested the hypothesis that intraoperative KGP could be assessed via thermal changes using a modern high-spec infrared video
camera.
Methods : Patients scheduled to receive kidney transplantation from a living donor were enrolled prior to surgery in this pilot study. The thermal changes of the transplanted kidney were visually and quantitatively evaluated for 1 minute just after unclamping the renal artery. The region of interest was the surface of the transplanted kidney. Maximal, minimal, and mean temperatures were measured and compared before and at 15, 30,
and 60 seconds after unclamping. Serum creatinine levels were monitored before surgery and on post-operativedays 1, 3, and 6.
Results : A total of 5 recipient-donor pairs were analyzed. Thermal increases of the transplanted kidney wereclearly visualized. The effects of a spastic renal artery could be detected as a delay in thermal recovery. The
presence of perirenal fatty tissue partially obstructed the monitoring of thermal increases after unclamping therenal artery. The findings of the infrared video camera did not impact post-operative serum creatinine level recovery.
Conclusions : A high-spec infrared video camera may be a useful tool to evaluate KGP of transplanted kidneys
intraoperatively, especially for detecting spasms of the renal artery. Shinshu Med J 72 : 219 ―225, 2024
(Received for publication January 17, 2024 ; accepted in revised form April 2, 2024)
Key words : living donor kidney transplantation, infrared video camera, kidney graft perfusion
Abbreviations : KGP, kidney graft perfusion ; KT, kidney transplantation ; LDKT, living donor kidney transplantation ; PEKT, preemptive kidney transplantation ; POD, post-operative day ; ROI, region of interest
Ⅰ Introduction

ied has been the length of graft preservation time alongwith consecutive ischemia-reperfusion injury causing

Kidney transplantation (KT) has become the pro-endothelial damage and acute tubular necrosis1）2）.

cedure of choice for treating patients with chronic

Therefore, monitoring kidney graft perfusion (KGP)

terminal renal dysfunction. The causes leading to de-is extremely important for successful KT. KGP in thelayed graft function include a variety of donor andtransplanted kidney is generally evaluated using grossrecipient factors, among which one of the most stud-appearance including color and size, physical findings＊

Corresponding author : Tomonori Minagawa
Department of Urology, Shinshu University School of
Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
E-mail : minagawat@shinshu-u.ac.jp

No. 4, 2024

such as hardness, and ultrasonographic findings that
include color Doppler ultrasonography. However, grossappearance and physical findings of the kidney are
not objective, and resistive index and pulsatility in219

Ueno・Minagawa・Kurita et al.

dex tend to ultrasonographer’s skills. Meanwhile, sig-

to the urinary bladder using the Lich-Gregoir method,nificant advances have been made in imaging tech-with 1.5 cm of spatulated ureter and 1.5 cm of sub-nology, with infrared video cameras producing clear,mucosal tunnel. After unclamping the renal vein con-high-resolution images and footage that can be ana-

nected to the external iliac vein, the renal artery was

lyzed in many situations. However, the use of suchthen unclamped. Next, the reperfusion of blood supply

technology is currently limited in the medical fieldin the transplanted kidney was recorded using an

and has not been reported sufficiently. We hypothe-

infrared video camera (X-HR, ViewOhre imaging Co.,

sized that KGP was reflected by thermal changes inLtd., Tokyo, Japan) set to a high resolution of 0.05

the kidney surface, which could be visualized anddegrees Celsius. The thermal changes of the trans-monitored using a high-spec infrared video camera.

planted kidney surface were visually and quantita-

The present study analyzed the thermal changes of

tively evaluated for 1 minute just after unclamping

transplanted kidneys using an infrared video camera

the renal artery.

towards the intraoperative evaluation of KGP in living donor kidney transplantation (LDKT).
ⅡＡMaterials and Methods

Study design and ethical statement

All of the images were obtained using a high-spec
infrared video camera almost 30 cm away from thetransplanted kidneys. The region of Interest (ROI) on
the images was the surface of the transplanted kidney.
The ROI was set using oval shape range conformableThis pilot study was conducted as an observative

to transplanted kidney excluding renal arteries, veins,

single-arm trial. All procedures were performed

and ureters. Maximal, minimal, and mean tempera-

in accordance with the standards of the Ethics Com-tures on the ROI were measured and compared before

mittee of Shinshu University School of Medicine, theand at 15, 30, and 60 seconds after unclamping. All

Helsinki Declaration of 1975 (2008 revision), and thedata were automatically analyzed using the software

Ethical Guidelines for Clinical Studies issued by the

included with the infrared video camera (Thermal

Ministry of Health, Labor, and Welfare of Japan, which

ViewX-HR-B, ViewOhre imaging Co., Ltd., Tokyo,

was revised in 2008 and enforced in April 2009. Per-

Japan).

mission number was 4755-2020 (accepted : June 1,

Ｄ Visual and quantitative analysis of kidney2020).

surface temperatureＢ

To establish a methodology for evaluating thermal

Participants
Patients who were scheduled to receive LDKT werechanges of the kidney surface after LDKT, the mean,enrolled in this investigation prior to surgery. Since

maximal, and minimal temperatures of each case were

this trial was conducted as a pilot study towards ex-recorded before unclamping and at 15, 30, and 60 sec-ploring further steps with a high-spec infrared video

onds after unclamping along with visual assessment.

camera, no exclusion criteria were specified.

Similarly, to examine the effects of such kidney con-Ｃ

ditions as fatty tissue accumulation and renal artery

Surgical procedures and protocol
All transplanted kidneys were obtained by hand-spasms, the changes in mean, maximal, and minimal

assisted laparoscopic donor nephrectomy. The re-temperature of each case were compared before andmoved kidney was immediately perfused with 930

after unclamping.

mL of preservation solutions (Euro Collins solution,

Ｅ

Serum creatinine levels and urine volume

CritiCare Pharma Co., Ltd., Atsugi, Japan). The trans-

Before and after KT, serum creatinine levels wereplanted kidney was placed on the right iliac fossa of

determined and compared among the recipients andthe recipient. The renal artery was connected to thedonors. Blood samples at 1 week before KT wereinternal iliac artery by end-to-end anastomosis. The

employed for the highest value of serum creatinine

renal vein was connected to the external iliac vein bylevels. Blood samples after KT were obtained on post-

end-to-side anastomosis. The ureter was connected

operative day (POD) 1, 3, and 6. Moreover, urine vol-220

Shinshu Med J

ol. 72

Patients
A total of 5 recipient-donor pairs involved in LDKT

Hight
(cm)

were enrolled in this study. All kidney grafts wereobtained from the left side. The characteristics of theAge(y.o.)

enrolled patients are summarized in Table 1. Data

recovered spontaneously almost 5 to 10 minutes after
unclumping.
Ｃ

ney surface temperature of each case are presented
in Fig. 2. Moreover, timedependent changes (Δ) of
each case were presented in Fig. 3. In general, maximal temperatures did not change remarkably before
and after unclamping the renal artery. In contrast,
the maximal, mean, and minimal temperatures reflected the condition of the transplanted kidney, suchas arterial spasms. Regarding the changes in mean,
maximal, and minimal kidney surface temperature,
the mean and minimal temperatures showed comparable tendencies apart from the cases of spastic renalartery and fatty kidney.
Ｄ

Serum creatinine levels and urine volume
The serum creatinine levels of recipients and doNo. 4, 2024

Recipient

The baseline tempareture of the transplanted kid-

F
M
M
M
F
HD
PEKT
HD
PEKT
PEKT
20.3
24.6
18.4
22.2
23.7
52
72
55
52
66
160
171
173
153
167
64
35
19
69
63
M
M
M
F
M

Weight(kg)

Quantitative analysis of ROI

Infectious nephritis
IgA nephropathy
Alport syndrome
IgA nephropathy
Diabetic kidney disease

ultrasonographic findings of renal artery. The spasm

215
177
139
100
200

nosed with intraoperative physical appearance and

169
155
125
141
197

tery after unclamping. Renal aortic spasm was diag-

405
512
370
381
575

changes were suppressed due to a spastic renal ar-

Incompatible
Incompatible
Compatible
Compatible
Compatible

covered the renal surface. In case 3, the thermal

Hight
(cm)

hampered in case 2, in which perirenal fatty tissue

Gender Age(y.o.)the thermal changes of the transplanted kidney wasUnderlyning cause of
CKD

after unclamping the renal artery. Visualization of

WIT
(sec)

changes are visible in a time-dependent manner justTable 1in Fig. 1. In case 1, the typical intraoperative thermal

Characteristics of the enrolled patients

The representative findings of 3 cases are shown

Case 1Case 2
Case 3
Case 4
Case 5Visual evaluation

TIT
(min)

Ｂ

Renal
BMI
replacement(cm2/kg)
therapystasis.

Operative
time
(min)

due to intraoperative management, including hemo-

ABO
Compatibility

case 2 and at 60 seconds after unclamping in case 5

GenderDonnerwere not acquired at 30 seconds after unclamping in

CKD : chronic kidney disease, BMI : body mass index, HD : hemodyalysis, KT : kidney transplantation, PEKT : pre-emptive kidney transplantation, POD : post-operative day,
TIT : total ischemic time, WIT : warm ischemic time

Ａ

20.2
25.8
25.5
22.6
20.6

Ⅲ Results

48
72
72
60
52

WeightBMI(kg)(cm2/kg)

6 : 00 am in the day after KT.

154
167
168
163
159

Urine volume on POD 0 was measured from KT to

65
65
49
73
60

Numberof renal
arteryume was measured after surgery on POD 0, 1, and 2.

1
1
1
2
1

Impact of high-spec infrared video camera during living donor kidney transplantation

221

Ueno・Minagawa・Kurita et al.

Fig. 1 Representative findings of intraoperative transplanted kidney using an infrared video camera(A) Case 1. The typical case of a time-dependent increase in transplanted kidney surface temperature. (B) Case 2.
A case of kidney graft with fatty tissue adheasion. The surface temperature did not recovere on the area covered
with fatty tissue after unclamping. (C) Case 3. A case of renal artery spasm just after unclamping the renal artery.
No time-dependent increase in kidney surface temperature was observed.

Fig. 2 The baseline temperature of kidney surface just before declumping of renal aretery.
Maximal, minimal, and mean tempareture were presented in each case.

222

Shinshu Med J

ol. 72

Impact of high-spec infrared video camera during living donor kidney transplantation

Fig. 3 Time-dependent changes (Δ) in transplanted kidney surface temperature for each case(A) Mean temperature. (B) Maximal temperature. (C) Minimal temperature.

Fig. 4 Serum creatinine levels before and after KT(A) Recipients before and on POD 1, 3, and 6. (B) Donors before and on POD 1.

nors are shown in Fig. 4 for pre-transplantation andsurface could be visualized just after unclamping theon POD 1, 3, and 6. No remarkable differences in se-

renal artery, which supported this method as a can-rum creatinine levels and urine folume were detect-didate for evaluating KGP towards the preservation

ed after KT.

of kidney function, excluding cases of spasm of the
Ⅳ Discussion

renal artery. Theoretically, areas of poor perfusion
may be detectable by this method. In the quantitative

KT has evolved significantly since its beginnings

ROI analysis, the findings were easily interpreted

in the early 1900’s and even more after the first suc-while monitoring the thermal changes of the trans-

cessful transplant performed by Dr. Joseph Murrayplanted kidney surface. These results indicate that3）

in 1954 . Ischemia times in KT have been shown as

the mean or minimal temperatures of the implanted

accurate predictors of future graft function. The pres-kidney using the infrared video camera may be use-ent pilot study was conducted to explore the utility

ful to evaluate KGP and signal further investigation.

of intraoperative KGP assessment using a high-spec

Considering the findings of each case, the summarized

infrared video camera in LDKT patients. Our results

results of mean and minimal temperatures had similar

demonstrated that thermal changes of the kidney

results and might be a useful tool for monitoring KGP

No. 4, 2024

223

Ueno・Minagawa・Kurita et al.

in LDKT. However, the post-surgical serum creati-

heated surface was cooled down by surrounding coldnine levels of recipients did not change remarkably,area of transplanted kidney. Therefore, this finding

indicating that a short delay in thermal recovery did

can be a clue to detect spasm of renal artery. This

not lead to serious functional damage of the trans-

hypothesis should be confirmed in the further inves-planted kidney. Indeed, avoiding a long delay in ther-

tigations.

mal recovery and segmental infarction of the trans-

Reports on infrared cameras and video-capturing

planted kidney is extremely important in KD. Although

instruments are few, especially in the clinical field.

the reported cohort did not contain segmental infarc-

The usefulness of an infrared camera was describedtion of the transplanted kidney, post-surgical kidney

for evaluating inflammation and neuropathy of thefunction is influenced by multiple factors, including

foot in diabetic patients8）9）. Such devices have also

donor kidney function, immunological reactions, andbeen used to diagnose skin cancer10）11） and evaluate

more. Further investigations are needed to establish

peripheral vascular diseases12）13）. In a previous study

the exact role of the infrared video camera.

on KT, the importance of thermodiffusion was inves-

This trial was conducted as a pilot study to explore

tigated to highlight perioperative cortical microper-a recent methodology to evaluate thermal changes offusion for transplanted kidney function14）. Further-

the renal surface in LDKT. This modality may be

more, the merits of an infrared camera were describeduseful to detect spastic conditions of the renal arteryfor evaluating transplanted kidneys in children by

and have value in the intraoperative management of

Fernandez et al.15）, although they used spot monitor-

KGP. However, perirenal fatty tissue might obstruct

ing of thermal changes and not area monitoring.

detection of the exact thermal changes of the kidney

Therefore, to the best of our knowledge, the present

surface and KGP measurement using the device. Ac-

study is the first to demonstrate the usefulness of acordingly, such tissue should be thoroughly removed

high-spec infrared video camera for assessing intra-

in further investigations. Moreover, this modality may

operative KGP in KT with the surface of the kidney

be also useful to detect spastic change of renal arteryas the ROI.

intraoperatively. Periarterial papaverine application

This trial had certain limitations that must be con-

was used for improvement of kidney function to pre-sidered when interpreting the results. First, the num-

4）
-7）

.

ber of enrolled participants was small and should be

Indeed, detection of renal spastic change is often dif-increased in future studies. Second, the correlations

ficult under KT, although intraoperative spastic change

between the infrared video camera and kidney func-of renal aretery should be avoided for smooth recov-

tion findings after KT were not investigated in detail.

ery of renal function. High-spec infrared video cam-

Especially, post-surgical kidney function should beeras may contribute for adequate intraoperative man-evaluated with long-term follow up. Third, the ther-agement of KT via early detection of renal areterial

mal changes of the transplanted kidney surface might

spasms.

not have directly corresponded to KGP. Since the trans-

vent renal arterial spasms in the previous reports

On the other hand, the specific finding can be foundplanted kidney can be heated by the attaching or-in the process of maximal temperature of kidney

gans and ambient temperature, the observation con-surface in the case 3. Spastic change might influence

ditions should be more closely taken into consideration.

on change of the maximal temperature. The maximal

Lastly, the lack of data points is an area of concern.

temperature was decreased at 60 seconds after de-In the clinical setting, obtaining a movie for 1 minuteclumping of renal artery. This finding may indicate

may be difficult considering the intraoperative man-that insufficient blood flow of renal arteries may in-agement of bleeding. Additional investigations ad-crease of kidney surface temperature just after de-

dressing the above limitations are necessary. None-clumping. However, insufficient blood flow cannot in-theless, the advantages of a high-spec infrared video

crease the surface temperature continuously, and thecamera are numerous, including non-invasiveness224

Shinshu Med J

ol. 72

Impact of high-spec infrared video camera during living donor kidney transplantationand objectivity. Especially, objectivity, such as quan-Ⅴtitative analysis, of infrared video-camera may be im-

Conclusions

portant considering lack of that about color Doppler

A high-spec infrared video camera may be usefulultrasonography. Therefore, comparison between ul-

to evaluate renal blood perfusion of the transplanted

trasonography and infrared video-camera should bekidney intraoperatively based on the obtained visual

done in the further steps. Our results indicate a valu-

and quantitative evaluation results. Especially, a spas-able role of such a device that warrants further study.

tic renal artery may be easily and promptly detectedby this method.

References
1） Ojo AO, Wolfe RA, Held PJ, Port FK, Schmouder RL : Delayed graft function : risk factors and implications for renal
allograft survival. Transplantation 63 : 968-974, 1997
2） Peters TG, Shaver TR, Ames JEt, Santiago-Delpin EA, Jones KW, Blanton JW : Cold ischemia and outcome in 17,937
cadaveric kidney transplants. Transplantation 59 : 191-196, 1995
3） Murray J : Interview with Dr Joseph Murray. Am J Transplant 2 : 803-806, 2002
4） Razzaghi MR, Heidari F : A Comparative Study on the Effect of Lidocaine and Furosemide on Urinary Output andGraft Function after Renal Transplantation. Urol J 1 : 256-258, 2004
5） Zacherl J, Bock S, Feussner H, Erhardt W, Siewert JR, Stangl M : Periarterial application of papaverine during
laparoscopic donor nephrectomy improves early graft function after kidney transplantation in pigs. Surg Endosc
18 : 417-420, 2004
6） Zacherl J, Stangl M, Feussner H, et al : Periarterial papaverine application improves intraoperative kidney function
during laparoscopic donor nephrectomy. J Surg Res 103 : 268-271, 2002
7） Ciapetti M, di Valvasone S, di Filippo A, Cecchi A, Bonizzoli M, Peris A : Low-Dose Dopamine in Kidney Transplantation.
Transplant Proc 41 : 4165-4168, 20098） van Doremalen RFM, van Netten JJ, van Baal JG, Vollenbroek-Hutten MMR, van der Heijden F : Infrared 3D Thermography for Inflammation Detection in Diabetic Foot Disease : A Proof of Concept. J Diabetes Sci Technol 14 : 4654, 2020
9） Bharara M, Cobb JE, Claremont DJ : Thermography and thermometry in the assessment of diabetic neuropathic
foot : a case for furthering the role of thermal techniques. Int J Low Extrem Wounds 5 : 250-260, 2006
10） Verstockt J, Verspeek S, Thiessen F, Tjalma WA, Brochez L, Steenackers G : Skin Cancer Detection Using Infrared
Thermography : Measurement Setup, Procedure and Equipment. Sensors (Basel) 22 : 3327, 2022
11） Magalhaes C, Vardasca R, Mendes J : Recent use of medical infrared thermography in skin neoplasms. Skin Res
Technol 24 : 587-591, 201812） Skversky NJ, Herring AB, Baron RC : Thermography in Peripheral Vascular Diseases. Ann N Y Acad Sci 121 : 118134, 1964
13） Buchwald W, Habighorst LV, Hulse R : Thermography in blood circulation disorders of the extremities. Radiologe
13 : 329-334, 1973
14） Angelescu M, Kraus T, Wiesel M, Hergesell O, Haberkorn U, Klar E : Assessment of renal graft function by perioperative
monitoring of cortical microcirculation in kidney transplantation. Transplantation 75 : 1190-1196, 2003
15） Fernandez M, Lorenzo A, Chua M, Koyle MA, Farhat W, Matava C : Real-time KGP monitoring using infrared imaging
during pediatric kidney transplantation. J Pediatr Urol 15 : 222 e1-222 e7, 2019（2024. 1. 17 received ; 2024. 4. 2 accepted）

No. 4, 2024

225