Just how good is multiparametric, 3-T MRI at finding, staging localized disease?

It is clear that modern magnetic resonance imaging is getting closer to being able to make a major difference to the way that we diagnose (and potentially manage) localized prostate cancer … always assuming we can afford the costs involved (at least here in the USA).

A group of French researchers (Largeron et al.) recently published data from the use of multiparametric, 3.0-Tesla (3-T) MRI in combination with a pelvic phased-array coil including T2-weighted imaging (T2W), dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping. They were able to compare the results of such imaging studies to pathological data provided by the prostatectomy specimens in a series of men who went on to have a radical prostatectomy.

This was a prospective study that enrolled a total of 74 patients over a period of 30 months. All patients had initially been diagnosed with prostate cancer on the basis of standard, systematic prostate biopsies. All were eligible for a radical prostatectomy. And all of them were also given a multiparametric, 3-T MRI. The researchers divided each gland in “octants” and then set out to compare the MRI data to the post-surgical pathology data on the basis of three different criteria: ability to detect cancer; ability to identify capsular contact; and ability to detect extracapsular extension (ECE).

Here are the findings:

  • 124 significant tumors (with a volume of ≥ 0.1 cm3) were identifiable in 8 × 74 = 592 octants.
  • The 3-T MRI had the general ability to detect cancer with
    • A sensitivity of 72.3 percent
    • A specificity of 87.4 percent
    • A positive predictive value (PPV) of 83.2 percent
    • A negative predictive value of 78.5 percent.
  • Capsular contact could be predicted with a high degree of negative power
    • A specificity of 96.4 percent
    • An NPV of 95.4 percent
  • Extracapsular extension could also be predicted with a high degree of negative power
    • A specificity of 97.5 percent
    • An NPV of 97.7 percent

Largeron et al. conclude that, in their hands,

  • “Multiparametric 3-T MRI with pelvic phased-array coil appeared to be a reliable imaging technique in clinical and routine practice for the detection of localized prostate cancer.”
  • Accuracy of the estimation of capsular contact and millimeter amounts of extracapsular extension “remains to be clarified, even if the negative predictive power for these parameters seems encouraging.”

2 Responses

  1. What percentage of the “missed” cancers were Gleason > 6?

  2. Doug:

    Je ne sais pas. (I don’t know.) The full text of the original article is in French and I have only seen the English abstract.

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