Hiroki Kadoya Yukiko Kitagawa

MEDIX VOL. 61

MEDIX VOL. 61 P.8 〜 P.11

Clinical Experience Using the Open Bore Multislice CT System Supria (16 slice CT)

〈MEDIX VOL.61〉

1. Introduction

Our hospital, which opened in Hirado, Nagasaki, in 1954,

currently has 52 beds. It has specialized departments in

internal medicine, surgery, pediatrics, gastrointestinal

medicine, cardiovascular medicine, proctology, radiology,

and rehabilitation.

As time had come to renew our CT system （Multislice

CT ROBUSTO, Hitachi Medical Corporation）, we decided

to install a new system.

In Hirado, Nagaski, the proportion of 65 years old or

older is relatively high at 33.2％1）. Our hospital also has a

geriatric health services facility in addition to a pediatrics

department. Therefore, in selecting the device, we mainly

considered the convenience of scan positioning, a reduced

rate of rescanning for patients in a hunched position, and

dose-reduction technology. Space and power requirements

comparable to those of a conventional CT system addition-

ally emerged as selection criteria, and therefore the deci-

sion was made in March 2014 to install the Supria※1 CT Fig. 1: Supria

system, manufactured by Hitachi Medical Corporation

（Fig. 1）.Here, we report on our experiences using this CT sys-

tem and present actual clinical images.

Clinical Experience Using the Open Bore Multislice CT System Supria （16 slice CT）

Key Words: Supria, FOV, Open Bore Gantry, Intelli IP

Clinical experience using the Supria※1 multislice （16 slice） CT system, manufactured by Hitachi Medical Corporation,

introduced at our institution in March, 2014 is reported below. Supria enables smooth and efficient operations and settings

to meet various scanning and patient positioning needs with its wide-open 750mm gantry bore and full data retention at the

maximum FOV （500mmφ）. Also, this CT system is capable of low exposure scanning, applying iterative reconstruction

technology as a standard function. Furthermore, it realizes both the fast speed and wide range acquisition of thin slice vol-

ume data for short-time and high-resolution imaging.

Kitagawa Hospital, Kouyuukai Medical Corporation （Hirado City, Nagasaki Prefecture）

Hiroki Kadoya Yukiko Kitagawa

〈MEDIX VOL.61〉

2. Outline of the installed system

Supria has a minimum scan time of 0.75s/rot and is

equipped with a 5MHU X-ray tube. It has a large gantry

bore of 750mm. Regardless of the field of view （hereinaf-

ter referred to as FOV） which is set when planning the

scan conditions, the system constantly retains all data at

the maximum FOV （500mm）.Given the frequent scanning of the elderly at our hospi-

tal, we judged that the system would contribute to reduc-

ing the rescanning rate. Furthermore, with regard to the

scanning of children, we judged that use of the system

would help to reduce their fear of examination.

The system has a footswitch, which can control the

movement of patient table based on the preset positions.

This ensures safety by freeing up both hands of the opera-

tor while also enabling smooth positioning of the patient.

The system is also equipped with a Breath guide－a useful

function for elderly patients that allows breath-holding

instructions to be displayed with characters. This function

is implemented by miniature monitors, placed at 3 sites

within the gantry. As for functions related to dose reduc-

tion, the system is equipped with “IntelliEC※2”, which

forms an elliptical model of the human body for each

patient to control the tube current, and “Intelli IP※3”, an

image processing technique that applies iterative recon-

struction which repeats the calculations to reduce the

noise both in projection space and image space.

We intend to reduce radiation exposure by utilizing

these functions not only when scanning children but dur-

ing all examinations.

3. Presentation of clinical images

（1） Clinical case 1 Brain image of a child: 6-year old boy

Scanning was performed with the protocol shown in

Table 1. For scanning unsedated children, the scan time

must be shortened. Although we considered performing a

non-helical scan by increasing the rotation speed to 0.75s/

rot since Supria installed here could generate outputs of

up to 400mA, we employed the scan conditions in Table 1

in consideration of the tradeoff with the view rate.

The brain image of a child generally shows less contrast

than that of an adult. However, the contrast obtained in

this case （Fig. 2） is likely to be sufficient for making clini-

cal diagnoses.

In addition, we consider that by jointly using Intelli IP,

it improves the image characteristics such as graininess,

and this leads to obtaining the images which are easy to

diagnose. For Intelli IP, the operator can select from

among seven levels （Level 1 to Level 7）. We confirmed

how noise varied at each level by using a water phantom.

Figure 3 shows the results for the rate of noise reduction

measured using the water phantom. In the case of scan-

ning conditions that assumed a pediatric brain scan, we

confirmed that the noise-reduction effect increased by

7.7％ on average for each increment in Intelli IP level.

Fig. 2: Brain image of a child: 6-year old boy

Fig. 3: Noise reduction effect of Intelli IP using a water phantom

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

FBP

SD

val

ue

Intelli IP levelLevel 1 Level 2 Level 3 Level 4 Level 5 Level 6 Level 7

100mAs200mAs240mAs250mAs300mAs350mAs400mAs

Table 1: Scanning conditions for Clinical case 1

kV mA Scan time Scan type

120 240 1.0 Normal

Slice thickness Collimation Tilt Kernel

5 0.625×16 11° F19

Figure 4 shows images in which Intelli IP was applied

to pediatric brain scans. The scanning conditions are iden-

tical to those indicated in Table 1. We studied whether

images with better visibility could be obtained owing to

the noise-reduction effect by increasing the level of Intelli

IP, even with actual clinical images. As a result of per-

forming SD measurements for each case at the epiphysis

level, it was confirmed that SD reduction effect is similar

to that of the phantom experiment. However, when the

level is increased excessively, our impression is that the

images become unsuitable for diagnostic use. In the case

〈MEDIX VOL.61〉

of the current pediatric brain scan conditions, we infer

that Level 2 or Level 3 is approximately the appropriate

level.

Table 2. Because Supria constantly retains all data at the

maximum FOV （500mm）, it can restore the lost portion

only by recalculation and can re-center the image （Fig.

5b）. When scanning is performed with a fixed tube cur-

rent, this reduces radiation exposure by approximately

69mGy per rotation compared to when rescanning is per-

formed.

Fig. 5: Brain image of patient with a hunched condition: 86-year old male

b: Re-calculationexample

a: Image lossexample

Table 2: Scanning conditions for Clinical case 2

kV mA Scan time Scan type

120 350 1.0 Normal

Slice thickness Collimation Tilt Kernel

5 0.625×16 9° F12

Fig. 4: Example of Intelli IP applied to the brain of a child: 9-year old boy

Level 4

FBP

Level 6

Level 2

Level 5

Level 1

Level 7

Level 3

（2） Clinical case 2 Brain image of patient with a hunched

condition: 86-year old male

In scanning patients who are hunched, image loss may

occur when the patient deviates from the FOV set at the

time of scanning. Figure 5a shows an image in which a

defect occurred under the scanning conditions shown in

（3） Clinical case 3 Adult lung image （arms lowered）: 92-year old female

At our hospital, scanning with the arms lifted is difficult

in some cases （e.g., with elderly patients）. Figure 6 shows

an image of the lungs （arms lowered） scanned under the

conditions shown in Table 3. The image suggests that arti-

facts such as those that arise from the upper forelimb

bone are reduced to a degree that is unproblematic for

diagnosis. This is presumably due to the effect of the

CORE technique for the newly installed 3D image recon-

struction algorithm, in addition to the effects of ADNR

（Automatic Data Noise Reduction）, an artifact suppres-

sion software program that had also been installed in the

previous system.

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However, increasing the level of Intelli IP appears to

change the visual quality. Specifically, image blurring

tends to intensify in accordance with the level of Intelli IP,

as shown in Fig. 4. This suggests that when considering

the compatibility between dose reduction and image qual-

ity, the proper level of Intelli IP and scanning conditions

should be continuously explored and established in accor-

dance with conditions such as age, sex, and scanned area of

the patient.

Although here we primarily investigated dose reduc-

tion in children, it will be important to continue investiga-

tions on optimizing scanning conditions （including Intelli

IP） so that radiation exposure can also be reduced during

other CT examinations.

5. Summary

Supria, manufactured by Hitachi Medical Corporation

and installed in our hospital, has a high degree of freedom

with regard to scan positioning during examination due to

its large gantry bore and constant retention of data within

the maximum FOV. In addition, because examinations

with a reduced dose are possible, we confirmed that the

system fits well with the classes of patient and regional

characteristics of our hospital and has high clinical utility.

High-resolution images can also be obtained even as the

breath holding time is shortened. This allows high-resolu-

tion images and low-dose examinations to be achieved

simultaneously－a feat that was difficult to achieve with

the previous system.

We suggest that this system can contribute to improv-

ing the quality of examinations （e.g., image quality） and

providing further benefits for patients.

※1 Supria, ※2 IntelliEC, and ※3 Intelli IP are registered trade-marks of Hitachi Medical Corporation.

References

1） 2010 Population Census, Statistical Tables According

to Prefecture, City, District, Town, and Village. （in

Japanese）2） K. Uchiyama et al.: Background Introduction and

Usage Experience of MDCT Supria from Hitachi

Medical Corporation. Radfan, Vol.11, No.15: 32-35,

2013. （in Japanese）

Fig. 7: Adult lung image （patient with difficulty assum-ing the dorsal position）: 86-year old male

Fig. 6: Adult lung image （arms lowered）: 92-year old female

Table 3: Scanning conditions for Clinical case 3

kV mA Scan time Scan type

120 200mA 0.75 Volume

Slice thickness Collimation Beam pitch Kernel

5 1.25×16 1.06 F22/F32

（4） Clinical case 4 Adult lung image （patient with diffi-

culty assuming a dorsal position）: 86-year old male

When scanning elderly patients, we sometimes encoun-

ter those that have difficulty assuming the dorsal position,

similar to cases of scanning with the arms lowered.

Figure 7 shows an image obtained by scanning in the

dorsal position.

For Supria installed here, which has a large gantry bore

of 750mm, the positioning of patients that need to be

scanned in an irregular position is relatively easy. In addi-

tion, our impression is that artifacts occur infrequently

even during scanning in an irregular position.

4. Future challenges

At our hospital, we consider it necessary to implement

further dose-reduction measures, particularly when scan-

ning children.

As has already been reported, when viewed in terms of

image SD values, a maximum dose-reduction effect of

approximately 80％ can be expected by using Intelli IP 2）.