Prostate and seminal vesicles after irradiation: MR appearance

Abstract

Familiarity with the morphologic changes in the prostate and seminal vesicles (SV) after pelvic irradiation is important to the correct interpretation of follow-up magnetic resonance (MR) studies. A retrospective study of 38 patients with prostatic or other pelvic tumors treated with radiation showed that 31.6% had a normal prostatic zonal pattern (peripheral zone hyperintense to central gland) on T2-weighted images, and 7.9% showed reversal of the zonal pattern; among the rest, the entire gland was diffusely isointense to fat in 42.1%, hypointense to fat in 10.5%, and hyperintense to fat in 7.9%. Sixty-three percent of the SV had a normal appearance, 21% had fewer tubules but normal signal intensity (SI), 8% had diffuse loss of SI (hypointense to fat), and 8% were hypointense to muscle. Quantitative measurements of SI of the prostate and SV demonstrated a statistically significant lower mean value for the irradiated patients relative to 10 control patients. A decrease in the size of both the prostate and SV was observed in 33% of patients with baseline studies. Use of additional treatment modalities in patients with prostatic carcinoma appeared to correlate with increased likelihood of developing abnormal changes. The authors conclude that in the irradiated patient, the prostate and SV can develop several patterns of SI abnormalities; in particular, diffuse low SI in the prostate and SV should establish radiation fibrosis as an important differential diagnosis to consider.

Role of magnetic resonance methods in the evaluation of prostate cancer: an Indian perspective

“…In addition, its use in the detection of recurrent tumor after surgery, radiation therapy, or hormone deprivation therapy is also documented [143][144][145][146][147]. The metabolite ratio [(Cho+Cr)/Cit] has been shown to be indicative of the tumor response to treatment [97,142,145].…”

Imaging of Local Recurrence in Prostate Cancer

“…Specifically, there is generalized loss of volume and effacement of the normal zonal architecture of the gland, with diffuse hypointensity on T2WI that diminishes contrast between recurrent tumor and benign tissue (Figure 2A) [39]. In this context, functional sequences are increasingly important (Figure 2).…”

Reproducibility of image interpretation in MRI of the prostate: application of the sextant framework by two different radiologists

“…Local extent of PCA, in turn, determines therapeutic options. In patients already treated for PCA by conservative means such as radiation therapy, hormone therapy, or watchful waiting, exact tumor localization within the prostate is necessary to determine therapeutic success by means of MRI [10][11][12][13]. However, the interpretation of MR images of the prostate remains subjective, although it follows defined criteria for the recognition of PCA [4][5][6][7][8].…”

“…Second only to lung cancer, it is also a leading cause of cancer death [1]. Magnetic resonance imaging (MRI) has been used to localize PCA to a sextant of the prostate, namely the right and left base, middle gland, and apex [2][3][4], to determine its location and stage prior to biopsy or therapy [5][6][7][8][9], and to follow up on PCA after different therapies, such as irradiation [10], cryosurgery [11,12] and hormonal ablation [13]. For all of its applications, tumor localization within the prostate is the key requisite to MRI of the prostate.…”