Value of the hemorrhage exclusion sign on T1-weighted prostate MR images for the detection of prostate cancer

Abstract

Purpose: To retrospectively determine the prevalence and positive predictive value (PPV) of the hemorrhage exclusion sign on T1-weighted magnetic resonance (MR) images in conjunction with findings on T2-weighted images in the detection of prostate cancer, with use of whole-mount step-section pathologic specimens from prostatectomy as the reference standard.

Materials and methods: The institutional review board approved this retrospective study, which was compliant with HIPAA, and the requirement to obtain informed consent was waived. Two hundred ninety-two patients with biopsy-proved prostate cancer underwent endorectal MR imaging followed by prostatectomy. The hemorrhage exclusion sign was defined as the presence of a well-defined area of low signal intensity surrounded by areas of high signal intensity on T1-weighted images. Two readers independently assessed the presence and extent of postbiopsy changes and the hemorrhage exclusion sign. The presence of a corresponding area of homogeneous low signal intensity on T2-weighted images was also recorded. The prevalence and PPV of the hemorrhage exclusion sign were calculated.

Results: Readers 1 and 2 found postbiopsy changes in the peripheral zone in 184 (63%) and 189 (64.7%) of the 292 patients, respectively. In these patients, the hemorrhage exclusion sign was observed in 39 of 184 patients (21.2%) by reader 1 and 36 of 189 patients (19.0%) by reader 2. A corresponding area of homogeneous low signal intensity was seen on T2-weighted images in the same location as the hemorrhage exclusion sign in 23 of 39 patients (59%) by reader 1 and 19 of 36 patients (53%) by reader 2. The PPV of the hemorrhage exclusion sign alone was 56% (22 of 39 patients) for reader 1 and 50% (18 of 36 patients) for reader 2 but increased to 96% (22 of 23 patients) and 95% (18 of 19 patients) when the sign was identified in an area of homogeneous low signal intensity on T2-weighted images.

Conclusion: Postbiopsy change is a known pitfall in the interpretation of T2-weighted images. The authors have shown that a potential benefit of postbiopsy change is the presence of excluded hemorrhage, which, in conjunction with a corresponding area of homogeneous low signal intensity at T2-weighted imaging, is highly accurate for cancer identification.

Figure 1a:

Images demonstrate value of concurrent reading of axial T2-weighted images. (a) T1-weighted image (1.5 T, 466.7/8.0) shows areas of high signal intensity that may be considered due to postbiopsy change in the peripheral zone of the prostate gland (arrows). (b) T2-weighted image (1.5 T, 5150.0/116.7), however, shows these areas to represent periprostatic fat (arrows).

Figure 1b:

Images demonstrate value of concurrent reading of axial T2-weighted images. (a) T1-weighted image (1.5 T, 466.7/8.0) shows areas of high signal intensity that may be considered due to postbiopsy change in the peripheral zone of the prostate gland (arrows). (b) T2-weighted image (1.5 T, 5150.0/116.7), however, shows these areas to represent periprostatic fat (arrows).

Figure 2a:

Hemorrhage exclusion sign in 50-year-old man with stage T3a prostate cancer. (a) Axial T1-weighted MR image (1.5 T, 500.0/7.9) shows hemorrhage exclusion sign (solid arrow) in right mid peripheral zone. (b) Axial T2-weighted image (1.5 T, 5500/107.2) shows matching area of low signal intensity (solid arrow). (c) Corresponding photomicrograph of specimen from step-section pathologic examination (hematoxylin-eosin stain; original magnification, ×1) shows tumor foci in the right mid peripheral zone (solid arrow; areas outlined in black are Gleason 4 foci; areas outlined in green are Gleason 3 foci; overall Gleason grade = 3 + 4). High signal intensity is noted on MR images in left mid peripheral zone, consistent with minor hemorrhage (open arrow in a); however, there is no abrupt cutoff. Although there is corresponding low T2 signal (open arrow in b), no tumor is seen on photomicrograph (open arrow in c), confirming that findings represent postbiopsy change.

Figure 2b:

Hemorrhage exclusion sign in 50-year-old man with stage T3a prostate cancer. (a) Axial T1-weighted MR image (1.5 T, 500.0/7.9) shows hemorrhage exclusion sign (solid arrow) in right mid peripheral zone. (b) Axial T2-weighted image (1.5 T, 5500/107.2) shows matching area of low signal intensity (solid arrow). (c) Corresponding photomicrograph of specimen from step-section pathologic examination (hematoxylin-eosin stain; original magnification, ×1) shows tumor foci in the right mid peripheral zone (solid arrow; areas outlined in black are Gleason 4 foci; areas outlined in green are Gleason 3 foci; overall Gleason grade = 3 + 4). High signal intensity is noted on MR images in left mid peripheral zone, consistent with minor hemorrhage (open arrow in a); however, there is no abrupt cutoff. Although there is corresponding low T2 signal (open arrow in b), no tumor is seen on photomicrograph (open arrow in c), confirming that findings represent postbiopsy change.

Figure 2c:

Hemorrhage exclusion sign in 50-year-old man with stage T3a prostate cancer. (a) Axial T1-weighted MR image (1.5 T, 500.0/7.9) shows hemorrhage exclusion sign (solid arrow) in right mid peripheral zone. (b) Axial T2-weighted image (1.5 T, 5500/107.2) shows matching area of low signal intensity (solid arrow). (c) Corresponding photomicrograph of specimen from step-section pathologic examination (hematoxylin-eosin stain; original magnification, ×1) shows tumor foci in the right mid peripheral zone (solid arrow; areas outlined in black are Gleason 4 foci; areas outlined in green are Gleason 3 foci; overall Gleason grade = 3 + 4). High signal intensity is noted on MR images in left mid peripheral zone, consistent with minor hemorrhage (open arrow in a); however, there is no abrupt cutoff. Although there is corresponding low T2 signal (open arrow in b), no tumor is seen on photomicrograph (open arrow in c), confirming that findings represent postbiopsy change.

Figure 3a:

Images in 63-year-old man. (a) Axial T1-weighted MR image (1.5 T, 583.3/8.2) shows hemorrhage exclusion sign (arrow) in central posterior peripheral zone mid gland. (b) Axial T2-weighted image (1.5 T, 4283.0/121.4) does not show a corresponding area of low signal intensity (arrow). (c) Photomicrograph (hematoxylin-eosin stain; original magnification, ×1) at same level confirms absence of a tumor focus in this region (arrow); however, tumor is seen in anterior left peripheral zone at this level and anteriorly within transition zone (areas outlined in black and green). Overall Gleason grade was 3 + 4, and overall pathologic stage was T2b.

Figure 3b:

Images in 63-year-old man. (a) Axial T1-weighted MR image (1.5 T, 583.3/8.2) shows hemorrhage exclusion sign (arrow) in central posterior peripheral zone mid gland. (b) Axial T2-weighted image (1.5 T, 4283.0/121.4) does not show a corresponding area of low signal intensity (arrow). (c) Photomicrograph (hematoxylin-eosin stain; original magnification, ×1) at same level confirms absence of a tumor focus in this region (arrow); however, tumor is seen in anterior left peripheral zone at this level and anteriorly within transition zone (areas outlined in black and green). Overall Gleason grade was 3 + 4, and overall pathologic stage was T2b.

Figure 3c:

Images in 63-year-old man. (a) Axial T1-weighted MR image (1.5 T, 583.3/8.2) shows hemorrhage exclusion sign (arrow) in central posterior peripheral zone mid gland. (b) Axial T2-weighted image (1.5 T, 4283.0/121.4) does not show a corresponding area of low signal intensity (arrow). (c) Photomicrograph (hematoxylin-eosin stain; original magnification, ×1) at same level confirms absence of a tumor focus in this region (arrow); however, tumor is seen in anterior left peripheral zone at this level and anteriorly within transition zone (areas outlined in black and green). Overall Gleason grade was 3 + 4, and overall pathologic stage was T2b.