Diagnostic Accuracy of Combined T2-weighted MR Imaging and H1MR Spectroscopy for Prostate Cancer Detection

doi:10.21203/rs.3.rs-5297397/v1

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Diagnostic Accuracy of Combined T2-weighted MR Imaging and H1MR Spectroscopy for Prostate Cancer Detection

https://doi.org/10.21203/rs.3.rs-5297397/v1

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Background

The primary objective was to evaluate the diagnostic accuracy of combining T2-weighted MR imaging and H1MR Spectroscopy in detecting prostate cancer, with histopathology serving as the reference standard.

Methods

The study included 125 male patients aged 44–78, who presented with clinical suspicion of prostate cancer (e.g., gland asymmetry, nodule, induration, adhesion, or palpable seminal vesicles). Patients with previous surgeries, hormonal or radiation therapy, or a biopsy within the last 12 weeks were excluded. MR imaging and H1MR Spectroscopy were conducted using a 1.5 Tesla scanner, and histopathology was used as the gold standard.

Results

The mean patient age was 63.17 ± 8.47 years. Of the 125 patients, 54 were true positives, 7 were false positives, 49 were true negatives, and 15 were false negatives. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 78.26%, 87.5%, 88.52%, 76.56%, and 82.4%, respectively.

Conclusion

The combination of T2-weighted MR imaging and H1MR Spectroscopy demonstrates high diagnostic accuracy in detecting prostate cancer. This technique, pending further validation, may serve as a reliable non-invasive diagnostic method in clinical practice.

Prostate cancer

Sensitivity

Specificity

MR Spectroscopy

Histopathology

Prostate cancer ranks as the second most common cancer and the sixth leading cause of cancer-related deaths among men globally, with approximately 899,000 new cases and 258,000 deaths reported in 2008. Notably, 72% of these cases and 53% of deaths occurred in developed countries, which comprise less than 20% of the global population [1]. Advancing age remains the most significant risk factor, though men younger than 65 account for 25% of cases [2]. Familial history, particularly with first-degree relatives diagnosed with prostate cancer, doubles the risk [3]. Other proposed risk factors include dietary habits, alcohol consumption, UV radiation exposure, chronic inflammation, and occupational hazards [4].

Prostate-specific antigen (PSA) testing is extensively used for early detection, diagnosis, staging, and follow-up of prostate cancer. However, PSA levels can be elevated due to benign conditions, leading to unnecessary biopsies, especially in patients with PSA levels between 4 and 10 ng/mL [5]. The standard diagnostic tool, ultrasound-guided biopsy, is invasive and subject to sampling errors [6].

Magnetic resonance imaging (MRI) has long been employed to assess prostate anatomy and pathology. T2-weighted (T2W) MR imaging provides critical information for treatment planning by detecting, localizing, and staging prostate cancer, including evaluating extracapsular extension and seminal vesicle invasion [7]. While T2W imaging is highly sensitive, its specificity is lower, particularly in differentiating between cancerous and benign tissues [8]. Functional MR techniques, such as 3D H1 MR Spectroscopy (H1MRS), have been introduced to improve the diagnostic capabilities of traditional MRI, providing more accurate detection of malignancies [9]. Studies have shown that combining T2W imaging with H1MRS increases sensitivity to 71% and specificity to 90%, with histopathology as the gold standard [10].

Given the limitations of biopsies, including associated complications and diagnostic uncertainties, there is a clear need for improved non-invasive methods to select candidates for biopsy. The rationale of this study is to evaluate whether combining MRI and MRS can enhance clinical outcomes by reducing unnecessary biopsies and better predicting the presence of malignancies. By doing so, the study also aims to address issues such as post-biopsy hemorrhages, which often compromise the quality of MRI images.

This study aims to assess the diagnostic accuracy of combining T2-weighted MR imaging and H1 MR Spectroscopy for prostate cancer detection, using histopathology as the gold standard.

A cross-sectional validation study was conducted in the Radiology Department at Allied Hospital, Faisalabad. A total of 125 male patients, aged 44 to 78 years, presenting with clinical suspicion of prostate cancer (PSA level 4–10 ng/mL) were selected through non-probability consecutive sampling. Patients with a history of surgery, hormonal or radiation therapy, or biopsy within the previous 12 weeks were excluded.

The clinical assessment included digital rectal examination (DRE), which may reveal asymmetry, nodularity, or induration of the prostate, and immobility of surrounding tissues. The study was approved by the hospital’s ethics committee, and informed consent was obtained from all participants. MRI examinations were performed using a 1.5 Tesla scanner with T2W fast spin-echo sequences in axial, coronal, and sagittal planes. MR spectroscopy was conducted using a surface coil and appropriate software, and histopathological analysis was used as the gold standard.

Data were analyzed using SPSS version 15. Descriptive statistics, including mean and standard deviation for age, were calculated. Diagnostic accuracy metrics, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy, were computed.

Out of the 125 patients, 48 (38.4%) were between 44 and 60 years of age, while 77 (61.6%) were aged between 61 and 78 years, with a mean age of 63.17 ± 8.47 years. Histopathological analysis confirmed prostate cancer in 69 patients (55.2%), while 56 (44.8%) were cancer-free. The diagnostic performance of the combined T2W MRI and H1MRS was assessed against histopathology, yielding the following results: 54 (43.2%) true positives, 7 (5.6%) false positives, 49 (39.2%) true negatives, and 15 (12%) false negatives. The sensitivity, specificity, PPV, NPV, and overall accuracy were calculated as 78.26%, 87.5%, 88.52%, 76.56%, and 82.4%, respectively.

Table 1

Age Distribution (n = 125)
Age(in years)	No. of patients	%
44–60	48	38.4
61–78	77	61.6
Total	125	100
Mean ± SD	63.17 ± 8.47

Table 2

Frequency of CA Prostate on Gold Standard (N = 125)
CA Prostate	No. of patients	%
Yes	69	55.2
No	56	44.8
Total	125	100

Table 3

Diagnostic Accuracy of T2-Weighted MR Imaging and HMR Spectroscopy for Detection of CA Prostate by Taking Histopathology as Gold Standard (n = 125), Sensitivity: 78.26%, Specificity: 87.5%, PPV: 88.52%, NPV: 76.56%, Diagnostic accuracy: 82.4%
T2W MRI + HMRS	Histopathology
T2W MRI + HMRS	CA Prostate Present	CA Prostate absent
CA Prostate + (Positive)	54 (43.2%)	7(5.6%)
CA Prostate – (Negative)	15(12%)	49(39.2%)

Our findings corroborate with previous studies that demonstrate the diagnostic accuracy of combining T2-weighted Magnetic Resonance Imaging (MRI) and High-Resolution ¹H Magnetic Resonance Spectroscopy (MRS) for the detection and localization of prostate cancer. In our study, the combination of T2W MRI and MRS achieved a sensitivity of 78.26%, a specificity of 87.5%, a positive predictive value (PPV) of 88.52%, and a negative predictive value (NPV) of 76.56%. This result aligns with earlier studies, such as the one conducted by Kumar et al., which reported a sensitivity of 71% and specificity of 90% for the combination of MRI and MRS [1]. By using histopathology as the gold standard, we could effectively validate the utility of these imaging modalities in enhancing cancer detection rates.

Magnetic Resonance Spectroscopy Imaging (MRSI) is particularly valuable as it non-invasively detects biochemical changes within prostate tissue. In cancerous tissue, elevated levels of choline-containing metabolites and decreased citrate levels are common biomarkers, reflecting the altered cellular metabolism of malignant cells [2]. The ability of MRS to detect these subtle metabolic shifts complements the anatomical imaging provided by MRI, allowing for a more comprehensive assessment of the prostate. In fact, MRSI's spatial resolution enables better identification of tumor aggressiveness and margins, which is critical for accurate staging and treatment planning.

Our study's results also emphasize the role of these combined imaging techniques in minimizing the number of unnecessary biopsies. By enhancing the precision of cancer detection and localization, MRI and MRS can reduce the frequency of false positives, and the morbidity associated with multiple biopsies. Previous studies have shown that the addition of MRS to conventional MRI improves cancer localization within prostate sextants, particularly in patients undergoing pre-operative imaging before radical prostatectomy. For instance, Weinreb et al. demonstrated that when both MRI and MRS were concordant in indicating the presence of cancer, specificity increased to 98%, with a sensitivity of 94% when any of the tests were positive [3]. These findings are consistent with our study, where a high PPV and NPV were observed, further confirming the utility of combined imaging modalities.

Another significant advantage of incorporating MRS is its ability to circumvent post-biopsy hemorrhage artifacts that often obscure the clarity of MRI images. Hemorrhage within the prostate following biopsy is a known issue that complicates imaging interpretation and typically necessitates a waiting period of 2–3 months before conducting another MRI scan. However, by using MRSI alongside MRI, our study—and others—have demonstrated that clinicians can make more accurate assessments immediately following biopsy, without needing to delay the evaluation. This is crucial in avoiding treatment delays, especially in aggressive cases [4].

While our findings show considerable promise in the early and accurate detection of prostate cancer using T2-weighted MRI and MRS, it is essential to recognize that these are preliminary results within our population. Larger, multi-center trials are necessary to validate these findings across diverse demographics and clinical settings. Future research should also explore the potential of integrating other advanced imaging techniques, such as multi-parametric MRI (mpMRI), which includes diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI, to further improve the diagnostic and prognostic capabilities of prostate imaging [5].

The combination of T2-weighted MR imaging and H1 MR Spectroscopy offers a promising non-invasive approach to improve the detection and diagnosis of prostate cancer. With an overall diagnostic accuracy of 82.4%, this technique has the potential to be integrated into clinical practice following further validation in larger trials.

Conflict of Interest

The authors report no conflict of interest.

Author Contribution

All attribution is to the primary author.

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No competing interests reported.

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Diagnostic Accuracy of Combined T2-weighted MR Imaging and H1MR Spectroscopy for Prostate Cancer Detection

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Abstract

Background

Methods

Results

Conclusion

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Introduction

Methodology

Results

Discussion

Conclusion

Declarations

Conflict of Interest

Author Contribution

References

Additional Declarations

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