In a primary cohort of 28 PCa patients with MRI-visible biopsy-proven disease, RP identified 39 Gleason score 7 (GS7) tumors, comprising 27 noncribriform and 12 cribriform lesions based on the dominant Gleason pattern 4 (GP4) phenotype (Fig. 1A). MRI-targeted biopsy identified only 7/12 cribriform tumors, with a sensitivity of 58%, consistent with prior reports (5). ADCratio and digital pathology-derived epithelial cell density showed no significant differences between cribriform and noncribriform tumors (Fig. 1B).

Using spatially resolved desorption electrospray ionization mass spectrometry imaging (DESI-MSI) in one subcohort (Fig. 1A), we found that unsaturated fatty acid biosynthesis was significantly enriched in cribriform epithelium (Fig. 1 C and D), with 7 out of the 10 most distinctively enriched metabolites being unsaturated fatty acids (SI Appendix). Immunohistochemistry in a second subcohort showed significant overexpression of the plasma membrane transporter for acetate (monocarboxylate transporter 1; MCT1) and fatty acid synthase (FASN) in cribriform GS7 tumors compared to noncribriform lesions (Fig. 1 E and F). Consistently, [1-¹¹C]acetate PET/CT demonstrated an average 1.5-fold increase in body-weight-normalized standardized uptake values (SUVbw) in cribriform lesions, sustained up to 60 min postinjection (P < 0.05; Fig. 1 G and H). Notably, two cribriform tumors misclassified on biopsy compared to prostatectomy had the highest [1-¹¹C]acetate uptake (Fig. 1G).

To complement the use [1-¹¹C]acetate PET/CT as a sensitive nuclear medicine technique which may not be routinely available outside centers with sufficient capacity for in-house [1-¹¹C]acetate production, we also explored ¹H-MRSI as an alternative clinical lipid imaging technique with high metabolite specificity and the potential to be added to the standard-of-care prostate MRI protocol. To do so, we performed ¹H-MRSI as part of routine imaging in a prospective cohort of 12 PCa patients who underwent ¹H-MRSI prior to an MRI-targeted biopsy (Fig. 2A). ¹H-MRSI-derived fat fraction showed an almost fivefold increase in cribriform GS7 lesions compared to all other tissue types, including GS7 noncribriform tumors, GS6 tumors, and histologically benign regions (P < 0.05; Fig. 2 B and C). These findings aligned with the DESI-MSI results, while the ADCratio showed no distinction between the three tumor subtypes (Fig. 2B).

This study demonstrates the feasibility of using two clinical metabolic imaging techniques—[1-¹¹C]acetate PET/CT and ¹H-MRSI—to improve noninvasive detection of crPCa by targeting its distinct metabolic features. Unlike our previous work, where DESI-MSI analysis was limited to just three metabolic pathways (10), here we leverage the full list of detected metabolites to confirm that increased fatty acid biosynthesis is among the most distinctive metabolic features of crPCa epithelium. As more in-depth studies of crPCa metabolism are conducted, the findings presented here warrant prospective multicenter validation in larger cohorts to assess the integration of metabolic imaging into routine clinical practice for improved crPCa detection.

Prior to surgery, all patients from the spatial metabolomics, immunohistochemistry, and [1-¹¹C]acetate PET/CT subcohorts provided written informed consent for participation in the DIAMOND (03/018), MISSION-Prostate (16/EE/0205), and APtITuDE (CUH/15/EE/0213) studies approved by the National Research Ethics Service (NRES) Committee East of England, Cambridge South. APtITuDE study was also approved by the Administration of Radioactive Substances Advisory Committee (certificate reference RPC/83/400/33606). All patients from the targeted biopsy cohort provided written informed consent for adding ¹H-MRSI to their standard-of-care prostate MRI protocol as part of the prospective study approved by NRES East of England, Cambridge South (16/EE/0346). ¹H-MRI ADCratio and epithelial cell density quantification methods have been described previously (10, 11). Detailed DESI-MSI and immunohistochemistry acquisition and analysis protocols are provided in the original cohort description (10). [1-¹¹C]acetate PET/CT and ¹H-MRSI acquisition and analysis protocols are provided in SI Appendix, with the [1-¹¹C]acetate production method detailed previously (12).