Quantitative Iodine-Based Material Decomposition Images with Spectral CT Imaging for Differentiating Prostatic Carcinoma from Benign Prostatic Hyperplasia

Rationale and Objectives

To investigate the value of iodine-based material decomposition images produced via spectral computed tomography (CT) in differentiating prostate cancer (PCa) from benign prostate hyperplasia (BPH).

Materials and Methods

Fifty-six male patients underwent CT examination with spectral imaging during arterial phase (AP), venous phase (VP), and parenchymal phase (PP) of enhancement. Iodine concentrations of lesions were measured and normalized to that of the obturator internus muscle. Lesion CT values at 75 keV (corresponding to the energy of polychromatic images at 120 kVp) were measured and also normalized; their differences between AP and VP, VP and PP, and PP and AP were also obtained. The two-sample t -test was performed for comparisons. A receiver operating characteristic curve was generated to establish the threshold for normalized iodine concentration (NIC).

Results

Fifty-two peripheral lesions were found, which were confirmed by biopsy as 28 cases of PCa and 24 BPHs. The NICs of prostate cancers significantly differed from those of the BPHs: 2.38 ± 1.72 compared with 1.21 ± 0.72 in AP, respectively, and 2.67 ± 0.61 compared with 2.27 ± 0.77 in VP. Receiver operating characteristic analysis indicated that an NIC of 1.24 in the AP provided a sensitivity of 88% and a specificity of 71% for differentiating PCa from BPH.

Conclusions

Spectral CT imaging enabled quantitative depiction of contrast medium uptake in prostatic lesions and improved sensitivity and specificity for differentiating PCa from BPH.

Cancer of the prostate (PCa) is the most common cancer in men and the second most common cause of cancer death . PCa and benign prostate hyperplasia (BPH) both rank among the 10 most diagnosed diseases in men over the age of 65 years . Although there is considerable overlap between BPH and PCa in symptom and risk profiles, management approaches are very different and appropriate differential diagnostic evaluation is crucial to achieve the best possible outcomes.

The main diagnostic tools for suspected carcinoma of the prostate are digital rectal examination, prostate-specific antigen (PSA) levels and associated parameters, and color Doppler transrectal sonographically guided biopsy . Although the latter is currently the best technique for detecting cancer in patients with elevated PSA or a positive digital rectal examination, it has its limitations. For example, septic complications after prophylactic antibiotics occur in 1% to 4% of patients and may require aggressive therapy . Therefore, a reliable noninvasive method of distinguishing malignant from benign disease would be of considerable benefit.

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Materials and methods

Patients

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CT Examinations

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Image Generation

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CT Analysis

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CECD-Targeted Biopsy and Pathological Analysis

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Quantitative Analysis

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Statistical Analyses

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Results

CT and CECD-Targeted Biopsy

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Image Analysis

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Quantitative Analysis

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Table 1

Quantitative Assessment of Iodine Concentrations and Computed Tomography (CT) Number Differences in Different Scanning Phases between Prostate Cancer (PCa) and Benign Prostate Hyperplasia (BPH)

PCa ( n = 28) BPH ( n = 24)P Value ∗ NIC AP † 2.38 ± 1.72 (1.55, 2.09) 1.21 ± 0.72 (0.90, 1.52) .00 (.41, 1.93) NIC VP † 2.67 ± 0.61 (2.35, 2.88) 2.27 ± 0.77 (1.95, 2.60) .04 (0, .78) NIC PP 2.51 ± 0.49 (2.28, 2.70) 2.35 ± 0.82 (2.00, 2.69) .37 (−.20, .53) NCT AP 0.96 ± 0.16 (0.90, 1.04) 0.90 ± 0.30 (0.78, 1.03) .33 (−.07, .19) NCT VP 1.30 ± 0.16 (1.22, 1.36) 1.28 ± 0.40 (1.14, 1.42) .79 (−.12, .16) NCT PP 1.23 ± 0.17 (1.14, 1.29) 1.22 ± 0.33 (1.11, 1.32) .83 (−.11, .13) DNCT VA ‡ 0.34 ± 0.15 (0.26, 0.39) 0.38 ± 0.28 (0.26, 0.50) .47 (−.17, .08) DNCT PV ‡ −0.07 ± 0.13 (−0.13, −0.18) −0.06 ± 0.15 (−0.13, 0) .87 (−.09, .07) DNCT PA ‡ 0.27 ± 0.19 (0.20, 0.34) 0.32 ± 0.31 (0.19, 0.45) .47 (−.19, .09)

AP, arterial phase; VP, venous phase; PP, parenchymal phase.

Value are mean ± SD (95% confidence interval).

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Diagnostic Implications

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Table 2

ormalized Iodine Concentration (NIC) Thresholds, Sensitivities, and Specificities for Distinguishing Prostate Cancer from Benign Prostate Hyperplasia

Phase AUC ∗ P † Threshold Sensitivity (%) ‡ Specificity (%) ‡ P § NIC AP 0.87 ± 0.05 (0.73, 0.94) .0054 (.06, .35) 1.24 88, 28, (72, 91) 71, 24, (65, 89) .03 NIC VP 0.66 ± 0.08 (0.49, 0.80) 1.96 84, 28, (69, 90) 55, 24, (49, 77) NIC PP 0.63 ± 0.08 (0.47, 0.77) 2.00 87, 28, (74, 90) 42, 24, (41, 68)

AP, arterial phase. VP, venous phase; PP, parenchymal phase.

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Discussion

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References

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Quantitative Iodine-Based Material Decomposition Images with Spectral CT Imaging for Differentiating Prostatic Carcinoma from Benign Prostatic Hyperplasia

Rationale and Objectives

Materials and Methods

Results

Conclusions

Materials and methods

Patients

CT Examinations

Image Generation

CT Analysis

CECD-Targeted Biopsy and Pathological Analysis

Quantitative Analysis

Statistical Analyses

Results

CT and CECD-Targeted Biopsy

Image Analysis

Quantitative Analysis

Diagnostic Implications

Discussion

References

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