MRI and 11C acetate PET/CT for prediction of regional lymph node metastasis in newly diagnosed prostate cancer

Patient characteristics
Patients, n	53
Age, median (range)	68 (55–76)
LN positive patients, n	26
PSA level ng/ml, mean (median, range)	24 (19, 3–112)
Biopsy Gleason score, n (%)
6	5 (9.4)
7	39 (73.6)
8	5 (9.4)
9	4 (7.5)
D’Amico risk classification, n (%)
Intermediate	6 (11.3)
High	47 (88.7)
Clincal T-stage, n (%)
T1c	1 (1.9)
T2	11 (20.8)
T3	41 (77.4)
Risk of LN invasion*, n
19–59%	27
≥ 60%	26

LN = lymph node;

* Calculated according to Briganti nomogram (26)

Table 2

Investigational findings at MRI DWI and ¹¹C Acetate PET/CT

MRI DWI and ¹¹C Acetate PET/CT findings
LN-ADCmean 10^-6 mm² /s, mean (SD) range	917 (191) 582–1398
LN-SUVmax, mean (SD) range	1.8 (1.2) 0.7–5.9
LN size mm, mean (SD) range	6.6 (3.7) 3.8–28.3
Proportion of LNs with round shape, n	19
Proportion of LNs with oval shape, n	34
MRI T-stage, n
< T3	25
T3a	14
T3b	14
LN ADC Roi size mm², median (range)	42 (16–334)
Tumor ADC Roi size mm²	≥ 80

[i] ADC = Apparent diffusion coefficient b0-b500; LN = lymph node; MRI T-stage: determined with MRI, only clear cut cases were reported as T3a and T3b; ROI = Region of interest; SUV = Standardized uptake value

Table 3

MRI DWI and ¹¹C Acetate PET/CT variables dichotomized using ROC curve and analyzed with simple logistic regression

	N0 n	N1 n	OR	95%CI	p-value	Threshold	AUC	Pseudo R²*	Sensitivity/Specificity/PPV/NPV
LN-ADCmean 10^-6 mm² /s	21	19	3.6	1.1-11.6	0.031	≤ 800	0.65	0.12	58/73/76/53
LN-SUVmax	28	25	5.4	1.6-18.7	0.008	≥ 1.6	0.68	0.18	72/68/52/83
LN-size mm	28	25	8.7	1.7–44.9	0.010	≥ 7.9	0.66	0.20	83/63/40/93
LN round shape	5	14	5.9	1.7-20.4	0.006		0.69	0.20	74/68/56/82
LN oval shape	23	11	ref	ref	ref	ref	ref	ref	ref
MRI-T-stage
≤ T2	18	7	ref	ref	ref	ref	ref	ref	ref
T3a	7	7	2.00	0.4-10.5	0.412
T3b	3	11	6.0	1.2-29.4	0.027		0.69	0.17	65/67/65/67

ADC = Apparent Diffusion Coefficient b0-b500; AUC = Area Under the Curve; CI = Confidence Interval; LN: lymph node; MRI T-stage: determined with MRI, only clear cut cases were reported as T3a and T3b; N0 = No lymph node metastases at ePLND (extended lymph node resection); N1 = Verified lymph node metastases at ePLND; NPV = Negative Predictive Value; OR = Odds Ratio; PPV = Positive Predictive Value; SUV = Standardized uptake value; Treshold calculated with ROC analysis; Bold numbers indicate highest values

* Nagelkerke’s R²

Table 4

MRI DWI and ¹¹C Acetate PET/CT variables dichotomized with ROC curve and analyzed with multiple logistic regression

Model*	M1	M2	M3	M4	M5	M6	M7	M8	M9	M10
	3.7	4.1	8.4	2.7
LN-ADCmean 10^-6 mm2 /s	(1.1–13.3),	(1.1–14.7),	(1.8–39.0),	(0.8–9.5),
	0.040	0.032	0.007	0.110
	5.6				2.7	4.7	2.3
LN-SUVmax	(1.5–20.6),				(0.6-11.1),	(1.1-20.5),	(0.5-10.7),
	0.010				0.179	0.040	0.30
		5.7			3.7			6.2	2.8
LN-shape		(1.5–21.2),			(0.9–15.0),			(1.4–27.2),	(0.5–14.7),
		0.010			0.069			0.016	0.226
			6.8			5.3		3.9		4.5
MRI T-stage T3ba / ≤ T2			(1.1–41.6),			(1.0–28.6),		(0.7–22.0),		(0.8–25.2),
			0.039			0.051		0.126		0.083
				7.5			4.8		3.8	9.3
LN-size mm				(1.4–40.3),			(0.7-34.7),		(0.4-31.6),	(1.4-61.1),
				0.018			0.116)		0.224	0.020

cPsedo R²	0.27	0.30	0.39	0.26	0.24	0.29	0.22	0.33	0.23	0.34
AUC	0.75	0.76	0.81	0.73	0.71	0.75	0.68	0.79	0.71	0.75
Sensitivity	72	74	67	83	63	65	68	74	74	74
Specificity	68	68	77	65	66	72	65	83	68	73
PPV	52	56	80	40	60	75	52	85	56	70
NPV	83	82	62	93	68	62	79	71	82	76
Cramers’Vb	0.09	0.15	0.16	0.25	0.54	0.28	0.66	0.37	0.72	0.34
Accuracy	69	70	71	69	64	68	66	78	70	73

AUC = Area Under the Curve; CI = Confidence Interval; LN = lymph node; MRI T-stage: only clear cut cases were reported as T3b, Apparent Diffusion Coefficient b0-b500, NPV = Negative Predictive Value; OR = Odds Ratio; PPV = Positive Predictive Value; SUV = Standardized uptake value; Bold numbers indicate highest values

* Model one through ten: presented with OR (95%CI), p-value.

a T3a is not presented in the table, this is because it is not significant in any of the ten models above.

c Nagelkerke’s R²

b Multicollinearity

References

Authors

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Articles in this issue

DOI: https://doi.org/10.2478/raon-2018-0001 | Journal eISSN: 1581-3207 | Journal ISSN: 1318-2099

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Language: English

Page range: 90 - 97

Submitted on: Aug 31, 2017

Accepted on: Nov 15, 2017

Published on: Jan 24, 2018

Published by: Association of Radiology and Oncology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

prostatic neoplasm,

lymph nodes,

lymph node excision,

diffusion magnetic resonance imaging,

positronemission tomography

Related subjects:

Medicine,

Clinical medicine,

Radiology

© 2018 Catrin von Below, Cecilia Wassberg, Rafael Grzegorek, Joel Kullberg, Charlotta Gestblom, Jens Sörensen, Mauritz Waldén, Håkan Ahlström, published by Association of Radiology and Oncology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Volume 52 (2018): Issue 1 (March 2018)