Head-to-Head Comparison of 68Ga-Prostate-Specific Membrane Antigen PET/CT and Ferumoxtran-10–Enhanced MRI for the Diagnosis of Lymph Node Metastases in Prostate Cancer Patients

Article Figures & Data

Download figure
Open in new tab
Download powerpoint
Download figure
Open in new tab
Download powerpoint
FIGURE 1.
Examples of iron-sensitive T2*-weighted fat-saturated nano-MRI images (left) and PSMA PET/CT images (right). (A) Seven-millimeter-diameter LN in left pararectal region that is positive on both nano-MRI and PSMA PET/CT. (B) Four-millimeter-diameter LN in region of left external iliac artery that is positive on nano-MRI but negative on PSMA PET/CT. (C) Suspicious LN dorsal to left external iliac artery that is negative on nano-MRI (nano-MRI also shows no left ureter in this area) but positive on PSMA PET/CT. LNs are encircled; arrows indicate right ureter.
Download figure
Open in new tab
Download powerpoint
FIGURE 2.
Size distribution of suspicious LNs as detected by nano-MRI (nMRI) and PSMA PET/CT.
Download figure
Open in new tab
Download powerpoint
FIGURE 3.
Anatomic distribution of identified suspicious LNs as detected by nano-MRI (nMRI) and PSMA PET/CT.

TABLE 1

Patient Characteristics

Characteristic	Data
Patients	45 (100%)
Age (y)	64 (48–82)
Serum PSA level (ng/mL)^*
Overall, n = 42	9.9 (0.0–150)
Primary setting, n = 8	28.9 (5.6–150)
Recurrence setting, n = 33	5.0 (0.0–46)
Time between diagnosis and scans (mo)^{^†}	50 (1–202)
Time between scans (d)	3.0 (1–18)
Before imaging
Any PCa treatment
Yes	36 (80%)
No	8 (18%)
Unknown	1 (2%)
PLND
Yes	22 (49%)
No	19 (42%)
Unknown	4 (9%)
Clinical ISUP grade
1	5 (11%)
2	6 (13%)
3	7 (16%)
4	13 (29%)
5	8 (18%)
Unknown	6 (13%)

TABLE 2

Node Detection and Characteristics for Nano-MRI and PSMA PET/CT

Characteristic	Total	Nano-MRI	PSMA PET/CT	P
Total scans	90 (100%)	45 (100%)	45 (100%)
Total positive scans	58 (64%)	33 (73%)	25 (56%)
Total suspicious LNs	179 (100%)	160 (89%)	71 (40%)
Suspicious LNs per patient	4.0 (range, 0–6)	3.6 (range, 0–15)	1.6 (range, 0–12)	<0.001^*
Suspicious LN size (mm)	5.2 (range, 2–16)	5.3 (range, 2–16)	6.0 (range, 3–16)	0.006^{^†}
LoS	4 (IQR, 4–5)	4 (IQR, 4–5)	5 (IQR, 4–5)

↵* Positive scan defined as at least 1 LN with LoS ≥ 3.
↵^† Wilcoxon signed-rank test.
^‡Mann–Whitney U test.
IQR = interquartile range.
Qualitative data are number and percentage; continuous data are mean and range or IQR.

TABLE 3

Conformity of Nano-MRI and PSMA PET/CT

		Suspicious LNs as detected by…
Characteristic	Both nano-MRI and PSMA PET/CT	Nano-MRI only	PSMA PET/CT only
No. of patients	20	30	14
Total suspicious LNs	52 (29%)	108 (60%)	19 (11%)
Suspicious LNs per patient	1.2 (range, 0–10)	2.4 (range, 0–8)	0.4 (range, 0–3)
LN size (mm)	6.5 (range, 4–16)	4.7 (range, 2–16)	4.4 (range, 3–8)
LoS	5 (IQR, 4–5)	4 (IQR, 4–5)	3 (IQR, 3–4)