Primary malignant tumours of the bony pelvis: US-guided high intensity focused ultrasound ablation

Figures & data

Table I. Patient and tumour characteristics.

Patient no.	Age/sex	Tumour location	Maximum tumour size (cm)	Pathology	Previous surgery	Chemotherapy	Treatment aim	HIFU sessions	Time to local tumour progression (months)	Follow-up duration (months)	Ablation ratio (%)
1	12/M	Left ilium	9.5	Chondrosarcoma	N	N	Curative	3	6	154	100
2	18/M	Right ischium	14.8	Primitive neuroectodermal tumour	Y	Y	Palliative	3	24	49*	81
3	15/M	Left ilium	17.5	Osteosarcoma	N	Y	Palliative	2	12	16*	92
4	70/F	Left ischium and ilium	11.2	Malignant fibrohistiocytoma	Y	N	Palliative	1	9	11*	74
5	59/F	Left ischium and ilium	6.5	Osteosarcoma	Y	Y	Curative	2	N/A	98	100
6	17/F	Left ilium	9.0	Ewing’s sarcoma	N	Y	Palliative	1	15	18*	76
7	32/F	Left ischium	5.6	Giant cell tumour	N	N	Curative	1	N/A	89	100
8	13/F	Right ilium	10.5	Osteosarcoma	N	Y	Palliative	3	18	25*	86
9	21/M	Left ilium	25.0	Chondrosarcoma	Y	Y	Palliative	7	6	21*	65
10	21/M	Right ilium	12.3	Osteosarcoma	Y	Y	Palliative	1	12	14*	80
11	19/F	Left ilium	7.0	Ewing’s sarcoma	N	Y	Curative	1	N/A	22	100

Patients were numbered in chronological order, according to the time of receiving HIFU ablation. *Denotes death during follow-up. N/A, not available. Ablation ratio, the volume of non-perfused region divided by the volume of the entire tumour after HIFU ablation.

Figure 1. Transverse MR in a 19-year-old girl with Ewing’s sarcoma in the left ilium who received curative HIFU ablation. (A) The tumour margin (arrow) was shown on T2-weighted MR before HIFU ablation. (B) The tumour (arrow) showed rich enhancement on T1-weighted contrast-enhanced MR before HIFU ablation. (C) One month after HIFU ablation, the ablation area (arrow) enveloped the entire tumour, which showed no enhancement on T1-weighted contrast-enhanced MR. (D) One year after HIFU ablation no enhancement was found in the ablation area (arrow) on T1-weighted contrast-enhanced MR.

Figure 2. Coronal MR in a 15-year-old boy with osteosarcoma in the left ilium who received palliative HIFU ablation. (A) T2-weighted MR of the tumour (arrow) before HIFU ablation. (B) The tumour showed evident enhancement on T1-weighted contrast-enhanced MR before HIFU ablation. (C) After one HIFU ablation session, the ablation area showed no enhancement (white arrow), the residual tumour (black arrow) still had enhancement. (D) After the second HIFU ablation session, almost the entire tumour showed no enhancement (arrow).