Magnetic resonance imaging-induced forces on video capsule endoscopes: First systematic in vitro assessment

Table 1 Characteristics of the tested video capsule endoscopes

Video capsule endoscope	Target organ	Cameras	Permanent magnet	Weight (g)	Length (mm)	Length of internal metal parts (mm)	Width (mm)
PillCam SB3	Small bowel	1	No	2.97	26.0	18.22	11.4
OMOM HD	Small bowel	1	No	3.188	26.1	19.53	11.5
MiroCam 1200	Small bowel	1	No	3.351	24.2	18.82	11.3
CapsoCam Plus	Small bowel	4	No	3.727	30.3	25.44	11.4
MiroCam 2000	Small bowel	2	No	3.634	30.0	20.23	11.2
PillCam Colon2	Colon	2	No	2.944	32.2	21.54	11.6
OMOM CC	Colon	2	No	2.956	33.3	23.42	11.7
NaviCam Colon	Colon	2	No	2.821	31.0	24.17	11.5
NaviCam	Stomach, small bowel	1	Yes	4.653	27.0	18.15	11.5
OMOM RC	Stomach	1	Yes	5.84	30.5	23.73	11.5
MiroCam Navi	Stomach	1	Yes	4.756	25.6	20.45	11.2

Length of internal metallic parts was measured by X-ray imaging.

Table 2 Calculated gravitational force and magnetically induced displacement force on the tested video capsule endoscopes

Video capsule endoscope	Gravitational force (mN)	Magnetically induced displacement force (mN)	F mag < F grav
PillCam SB3	29.14	288.27	Not fulfilled
OMOM HD	31.27	47.91	Not fulfilled
MiroCam 1200	32.87	571.96	Not fulfilled
CapsoCam Plus	36.56	672.66	Not fulfilled
MiroCam 2000	35.65	575.92	Not fulfilled
PillCam Colon2	28.88	299.57	Not fulfilled
OMOM CC	29.00	127.5	Not fulfilled
NaviCam Colon	27.67	21.96	Fulfilled
NaviCam	45.65	2232	Not fulfilled
OMOM RC	57.29	2366	Not fulfilled
MiroCam Navi	46.66	2415	Not fulfilled

Measurements were obtained at position 1 with the maximal gradient on the Z-axis (Z = 87 cm; |∇B| = 4.51 T/m; B = 1.78 T; B₀ × |∇B| = 8.03 T²/m). “Not fulfilled” indicates that the magnetically induced displacement force exceeded the safety threshold defined by the capsule’s gravitational force. F mag: Magnetically induced displacement force; F grav: Gravitational force.

Table 3 Magnetically induced torque on the tested video capsule endoscopes

Video capsule endoscope	Max magnetically induced torque (mNm)	Calculated upper bound of magnetically induced torque (mNm)	Worst-case torque due to gravity (mNm)	T mag < T grav
PillCam SB3	19.2	Not determined	Approximately 0.76	Not fulfilled
OMOM HD	5.1	Not determined	Approximately 0.82	Not fulfilled
MiroCam 1200	41.7	Not determined	Approximately 0.80	Not fulfilled
CapsoCam Plus	51.0	Not determined	Approximately 1.11	Not fulfilled
MiroCam 2000	54.0	Not determined	Approximately 1.07	Not fulfilled
PillCam Colon2	15.6	Not determined	Approximately 0.93	Not fulfilled
OMOM CC	5.1	Not determined	Approximately 0.97	Not fulfilled
NaviCam Colon	Below measuring limit	Not determined	Approximately 0.86	Fulfilled
NaviCam	Not determined	271.95	Approximately 1.23	Not fulfilled
OMOM RC	Not determined	289.02	Approximately 1.75	Not fulfilled
MiroCam Navi	Not determined	293.90	Approximately 1.19	Not fulfilled

For magnet-containing capsules, the upper bound of magnetically induced torque was calculated based on the measured displacement force. Worst-case torque due to gravity is shown for comparison. T mag: Magnetically induced torque; T grav: Gravitational torque.