DOI: 10.1148/rg.234025097
CT Signs of Urethral Injury1
Muhammad Ali, MBBS,
Yair Safriel, MBBCh,
Salvatore J. A. Sclafani, MD and
Robert Schulze, MD
1 From the Department of Radiology, Box 45, State University of New York, Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203 (M.A., Y.S., S.J.A.S.); and the Department of Surgery, Kings County Hospital Center, Brooklyn, NY (S.J.A.S., R.S.). Presented as an education exhibit at the 2001 RSNA scientific assembly. Received May 9, 2002; revision requested July 2; final revision received December 9; accepted December 16. Address correspondence to M.A. (e-mail: mali159@hotmail.com).
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Figure 1. Anatomy of the pelvis and perineum. Drawing of a coronal section shows the relationships of essential muscles, osseous structures, and fat planes.
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Figure 2. Anatomy of the pelvis and perineum. Drawing of the dissected perineum shows the ischiocavernosus muscle and its relationship to the crus of the penis and the ischiopubic ramus.
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Figure 3a. Anatomy of the prostate. (a) CT scan obtained through the pelvis shows the prostatic margin (arrows). p = substance of the prostate. (b) CT scan obtained 10 mm below a shows a clean preprostatic fat plane (arrowheads). oi = obturator internus muscle, p = prostate.
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Figure 3b. Anatomy of the prostate. (a) CT scan obtained through the pelvis shows the prostatic margin (arrows). p = substance of the prostate. (b) CT scan obtained 10 mm below a shows a clean preprostatic fat plane (arrowheads). oi = obturator internus muscle, p = prostate.
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Figure 4a. UGD. (a) CT scan shows the apices of the UGD fat planes (arrowheads). Note that the UGD (arrows) is contiguous to the prostatic apex (a). The right UGD fat plane at the level of the lower obturator internus muscle is outlined with white. (b) Contiguous section obtained below a shows the continuation of the UGD (arrow). Arrowhead = apex of the UGD fat plane.
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Figure 4b. UGD. (a) CT scan shows the apices of the UGD fat planes (arrowheads). Note that the UGD (arrows) is contiguous to the prostatic apex (a). The right UGD fat plane at the level of the lower obturator internus muscle is outlined with white. (b) Contiguous section obtained below a shows the continuation of the UGD (arrow). Arrowhead = apex of the UGD fat plane.
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Figure 5. Bulbocavernosus muscle. CT scan shows the posterior margin of the bulbocavernosus muscle (arrows). The bulb of the penis (b) is surrounded by this muscle (arrowheads). Note the small fat planes (areas of low attenuation) along the posterior margin of the bulbocavernosus muscle. The right UGD fat plane at the level of the ischiocavernosus muscle is outlined with white.
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Figure 6. Ischiocavernosus muscle. CT scan obtained through the lower pelvis shows the insertions of the ischiocavernosus muscles (white arrowheads) on the ischiopubic rami (black arrowheads). Note the sharp margins of the muscles and the clean fat planes medially.
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Figure 7. Obturator internus muscle. CT scan obtained at the midacetabular level shows bilaterally symmetrical, elliptical obturator internus muscles (arrowheads) along the medial aspects of the acetabula.
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Figure 8a. Type I injury. (a) CT scan obtained at the level of the UGD shows no identifiable prostatic apex. Extensive hematoma is seen (h). (b) CT scan obtained 2 cm above a shows a disrupted prostatic parenchyma (p) with surrounding hematoma (h). No prostatic tissue was identified in the section obtained immediately above a with 10-mm-collimation scanning. (c) RUG image shows a stretched prostatic urethra (arrows) and an elevated bladder apex (a).
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Figure 8b. Type I injury. (a) CT scan obtained at the level of the UGD shows no identifiable prostatic apex. Extensive hematoma is seen (h). (b) CT scan obtained 2 cm above a shows a disrupted prostatic parenchyma (p) with surrounding hematoma (h). No prostatic tissue was identified in the section obtained immediately above a with 10-mm-collimation scanning. (c) RUG image shows a stretched prostatic urethra (arrows) and an elevated bladder apex (a).
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Figure 8c. Type I injury. (a) CT scan obtained at the level of the UGD shows no identifiable prostatic apex. Extensive hematoma is seen (h). (b) CT scan obtained 2 cm above a shows a disrupted prostatic parenchyma (p) with surrounding hematoma (h). No prostatic tissue was identified in the section obtained immediately above a with 10-mm-collimation scanning. (c) RUG image shows a stretched prostatic urethra (arrows) and an elevated bladder apex (a).
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Figure 9a. Type II injury. (a) CT scan shows extravasated contrast material (arrows) in the urinary tract above the UGD. The balloon of a Foley catheter (b) is seen in the prostatic urethra. (b) RUG image obtained in another patient shows extravasated contrast material (arrows) above the UGD. The contrast material has tracked into the prevesical space in the pelvis (arrowheads); this finding is characteristic of a type II injury.
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Figure 9b. Type II injury. (a) CT scan shows extravasated contrast material (arrows) in the urinary tract above the UGD. The balloon of a Foley catheter (b) is seen in the prostatic urethra. (b) RUG image obtained in another patient shows extravasated contrast material (arrows) above the UGD. The contrast material has tracked into the prevesical space in the pelvis (arrowheads); this finding is characteristic of a type II injury.
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Figure 10a. Type III injury. (a) CT scan obtained through the perineal region shows extravasated contrast material (arrows) in the urinary tract below the UGD. (b) RUG image shows extravasated contrast material (arrows) in the urinary tract at the level of the UGD. A streak of contrast material (arrowheads) reaches the bladder, a finding compatible with a partial tear of the urethra. Injury to the membranous urethra, whether alone or in combination with injury above the UGD, constitutes a type III injury.
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Figure 10b. Type III injury. (a) CT scan obtained through the perineal region shows extravasated contrast material (arrows) in the urinary tract below the UGD. (b) RUG image shows extravasated contrast material (arrows) in the urinary tract at the level of the UGD. A streak of contrast material (arrowheads) reaches the bladder, a finding compatible with a partial tear of the urethra. Injury to the membranous urethra, whether alone or in combination with injury above the UGD, constitutes a type III injury.
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Figure 11a. Distortion or obscuration of the UGD fat plane. (a) CT scan of a patient with a type II urethral injury shows partial absence of the left UGD fat plane (arrow) with a normal right fat plane. (b) CT scan of another patient shows a fracture of the right ischiopubic ramus (arrow) with preservation of the contour and surrounding fat planes of the UGD (arrowheads).
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Figure 11b. Distortion or obscuration of the UGD fat plane. (a) CT scan of a patient with a type II urethral injury shows partial absence of the left UGD fat plane (arrow) with a normal right fat plane. (b) CT scan of another patient shows a fracture of the right ischiopubic ramus (arrow) with preservation of the contour and surrounding fat planes of the UGD (arrowheads).
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Figure 12a. Hematoma of the ischiocavernosus muscle. (a) CT scan of a patient with a type II urethral injury shows a fracture of the left ischiopubic ramus with a hematoma of the ischiocavernosus muscle (arrowheads) and absence of the adjacent fat plane. (b) Contiguous section obtained 10 mm above a shows arterial extravasation of contrast material (h). (c) CT scan of another patient shows a fracture of the left ischiopubic ramus (arrow) with preserved fat planes and no hematoma of the ischiocavernosus muscle. No urethral injury was seen at RUG.
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Figure 12b. Hematoma of the ischiocavernosus muscle. (a) CT scan of a patient with a type II urethral injury shows a fracture of the left ischiopubic ramus with a hematoma of the ischiocavernosus muscle (arrowheads) and absence of the adjacent fat plane. (b) Contiguous section obtained 10 mm above a shows arterial extravasation of contrast material (h). (c) CT scan of another patient shows a fracture of the left ischiopubic ramus (arrow) with preserved fat planes and no hematoma of the ischiocavernosus muscle. No urethral injury was seen at RUG.
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Figure 12c. Hematoma of the ischiocavernosus muscle. (a) CT scan of a patient with a type II urethral injury shows a fracture of the left ischiopubic ramus with a hematoma of the ischiocavernosus muscle (arrowheads) and absence of the adjacent fat plane. (b) Contiguous section obtained 10 mm above a shows arterial extravasation of contrast material (h). (c) CT scan of another patient shows a fracture of the left ischiopubic ramus (arrow) with preserved fat planes and no hematoma of the ischiocavernosus muscle. No urethral injury was seen at RUG.
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Figure 13a. Distortion or obscuration of the prostatic contour. (a) CT scan of a patient with a type I urethral injury shows absence of the normal prostatic outline. A periprostatic hematoma obliterates the fat planes. p = prostatic parenchyma. (b) CT scan of another patient shows a fracture of the superior pubic ramus (arrow) with a preserved prostatic contour and preserved preprostatic fat planes. RUG images were normal.
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Figure 13b. Distortion or obscuration of the prostatic contour. (a) CT scan of a patient with a type I urethral injury shows absence of the normal prostatic outline. A periprostatic hematoma obliterates the fat planes. p = prostatic parenchyma. (b) CT scan of another patient shows a fracture of the superior pubic ramus (arrow) with a preserved prostatic contour and preserved preprostatic fat planes. RUG images were normal.
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Figure 14a. Distortion or obscuration of the bulbocavernosus muscle. (a) CT scan of a patient with a type III urethral injury shows a distorted contour of the bulbocavernosus muscle (arrowheads) with an obscured fat plane. Note the air in the urethra, which resulted from an unsuccessful attempt at catheterization. (b) CT scan of a patient with a type I urethral injury shows a slightly obscured bulbocavernosus muscle, which cannot be clearly identified around the bulb of the penis (b). Arrowheads = expected location of the bulbocavernosus muscle. (c) CT scan of another patient shows a fracture of the left ischiopubic ramus with preserved fat planes (arrowheads) and no hematoma of the ischiocavernosus (arrow) or bulbocavernosus muscle. The patient had no urethral injury.
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Figure 14b. Distortion or obscuration of the bulbocavernosus muscle. (a) CT scan of a patient with a type III urethral injury shows a distorted contour of the bulbocavernosus muscle (arrowheads) with an obscured fat plane. Note the air in the urethra, which resulted from an unsuccessful attempt at catheterization. (b) CT scan of a patient with a type I urethral injury shows a slightly obscured bulbocavernosus muscle, which cannot be clearly identified around the bulb of the penis (b). Arrowheads = expected location of the bulbocavernosus muscle. (c) CT scan of another patient shows a fracture of the left ischiopubic ramus with preserved fat planes (arrowheads) and no hematoma of the ischiocavernosus (arrow) or bulbocavernosus muscle. The patient had no urethral injury.
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Figure 14c. Distortion or obscuration of the bulbocavernosus muscle. (a) CT scan of a patient with a type III urethral injury shows a distorted contour of the bulbocavernosus muscle (arrowheads) with an obscured fat plane. Note the air in the urethra, which resulted from an unsuccessful attempt at catheterization. (b) CT scan of a patient with a type I urethral injury shows a slightly obscured bulbocavernosus muscle, which cannot be clearly identified around the bulb of the penis (b). Arrowheads = expected location of the bulbocavernosus muscle. (c) CT scan of another patient shows a fracture of the left ischiopubic ramus with preserved fat planes (arrowheads) and no hematoma of the ischiocavernosus (arrow) or bulbocavernosus muscle. The patient had no urethral injury.
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Figure 15a. Hematoma of the obturator internus muscle. (a) CT scan of a patient with a type III urethral injury shows obvious asymmetry in the sizes and contours of the obturator internus muscles, an appearance compatible with a hematoma (h) of the left muscle. (b) CT scan of a patient with a RUG-proved type II urethral injury shows an extensive hematoma (h) of the obturator internus muscle. (c) CT scan of another patient shows fractures of the right pubic body (arrow) and left superior pubic ramus (arrowhead) with preserved fat planes, sharp medial margins, and nearly symmetrical sizes and contours of the obturator internus muscles; thus, no hematoma of the obturator internus muscle is present. Despite having significant pelvic fractures, the patient did not have a urethral injury.
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Figure 15b. Hematoma of the obturator internus muscle. (a) CT scan of a patient with a type III urethral injury shows obvious asymmetry in the sizes and contours of the obturator internus muscles, an appearance compatible with a hematoma (h) of the left muscle. (b) CT scan of a patient with a RUG-proved type II urethral injury shows an extensive hematoma (h) of the obturator internus muscle. (c) CT scan of another patient shows fractures of the right pubic body (arrow) and left superior pubic ramus (arrowhead) with preserved fat planes, sharp medial margins, and nearly symmetrical sizes and contours of the obturator internus muscles; thus, no hematoma of the obturator internus muscle is present. Despite having significant pelvic fractures, the patient did not have a urethral injury.
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Figure 15c. Hematoma of the obturator internus muscle. (a) CT scan of a patient with a type III urethral injury shows obvious asymmetry in the sizes and contours of the obturator internus muscles, an appearance compatible with a hematoma (h) of the left muscle. (b) CT scan of a patient with a RUG-proved type II urethral injury shows an extensive hematoma (h) of the obturator internus muscle. (c) CT scan of another patient shows fractures of the right pubic body (arrow) and left superior pubic ramus (arrowhead) with preserved fat planes, sharp medial margins, and nearly symmetrical sizes and contours of the obturator internus muscles; thus, no hematoma of the obturator internus muscle is present. Despite having significant pelvic fractures, the patient did not have a urethral injury.
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Copyright © 2003 by the Radiological Society of North America.
