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Genitourinary Imaging: The Past 40 Years¹

¹ From the Department of Radiology, University of Texas–Houston Medical School, 6431 Fannin St, MSB 2.132, Houston, TX 77030. Received October 6, 1999; revision requested November 1; revision received December 14; accepted December 20. Address correspondence to S.M.G. (e-mail: chairman@msrad3.med.uth.tmc.edu).

Abstract

During the past 40 years, there has been a dramatic evolution in genitourinary imaging. This evolution has resulted in fundamental changes in the subspecialty. Uroradiology initially focused on radiographic imaging of the urinary tract and was practiced primarily by urologists. After the development of safe intravenous contrast materials, radiologists who focused on the urinary tract and worked closely with urologists forged major advances in urinary tract imaging and intervention. More recently, imaging of the extraurinary genital organs has been added to the subspecialty. Cross-sectional imaging techniques have supplanted radiographic imaging for both urinary and genital imaging. The emergence of the cross-sectional techniques, however, has blurred the traditional organ system–based distinction between gastrointestinal radiology and genitourinary radiology, as both organ systems are imaged simultaneously, and has resulted in a new amalgamation, abdominal radiology, with roots in both specialties. The challenge for the new generation of abdominal radiologists, trained predominantly in cross-sectional techniques, will be to maintain the close interaction with our clinical colleagues that the traditional organ system orientation fostered.

Index terms: Genitourinary system, 80._**² • Radiology and radiologists, history • Radiology and radiologists, research

UROLOGIC IMAGING

The Early Years
In the beginning of uroradiology, only a glass abdominal flat plate (1) was available to evaluate the kidneys and bladder, and the physicians of the day said, "It was good." In the 1920s, collargol, a colloidal silver suspension, was introduced for depiction of the upper tracts and bladder by means of retrograde injection. The physicians of that era said, "This is better." Other retrograde agents, including air (Fig 1), carbon dioxide, and a variety of heavy metal compounds, were all subsequently tried.

View larger version (95K): [in this window] [in a new window] [Download PPT slide]   Figure 1. Anteroposterior retrograde air pyelogram demonstrates upper pole stones (arrowhead). This technique was still used by some urologists into the 1970s to demonstrate stones. Air introduced into the collecting system is still used by many interventional uroradiologists to identify posterior calices prior to percutaneous nephrostomy.

The next level in the uroradiologic firmament was attained in the 1950s and early 1960s with the development of the first triiodobenzoic acid derivatives, diatrizoate sodium (Hypaque) and iothalamate meglumine (Conray). These agents used a 6-carbon benzene ring as the carrier of the iodine. With the introduction of these contrast materials, intravenous urography (IVU) became the mainstay of urologic imaging, and uroradiology moved firmly from urology into radiology.

The 1960s
During this decade, as indicated earlier, IVU replaced retrograde pyelography as the most commonly performed urinary tract imaging study. The departments in which the authors worked performed 15–30 studies daily, Monday through Friday, with additional examinations performed on Saturday mornings. In most institutions, several radiography rooms were dedicated specifically to performing IVU. Many of the patients were examined as inpatients. IVU was commonly ordered as part of a "big four work-up"—IVU, upper gastrointestinal series, barium enema examination, and oral cholecystography—in patients with nonspecific abdominal complaints. In academic centers, the contrast material injection was performed and the IVU monitored by a radiology resident. All IVU images were hung on a rotator or view box and were reviewed in the afternoon by the attending radiologist, who might or might not be a uroradiologist.

The results of all studies were dictated, but it was common practice that a note of the findings be written on the file folder, since the typed reports were often returned from the typists a week or more later. Residents from the referring services would often consult with the radiology resident on an ad hoc basis. In some institutions, urology residents with an attending physician would meet daily in the afternoon for "rounds" with the radiology resident in the uroradiology department.

In performing IVU, great attention was payed to detail (5–7). The routine IVU consisted of a 14 x 17-inch scout radiograph and 1-, 5-, and 15-minute 10 x 12-inch radiographs coned to the kidneys. This was followed by 20-minute anteroposterior, posteroanterior, and both oblique (14 x 17-inch) radiographs of the entire abdomen. Essential to the study was the placement of abdominal compression, as described by Daughtridge (8), to distend the calices and ureters. A double-dose study was routinely performed: 50–60 mL of either 50% (weight-to-volume ratio) diatrizoate sodium (Hypaque), 60% (weight-to-volume ratio) iothalamate meglumine (Conray), or 60% (weight-to-volume ratio) diatrizoate sodium or diatrizoate meglumine (Renografin) was injected through an 18-gauge needle or scalp vein (9).

To test for sensitivity to contrast material, it was common to administer an initial 1-mL test dose of the contrast material intravenously (10). If, after 1 minute, the patient's vital signs remained stable, the remainder of the contrast material was administered. This procedure was abandoned by the 1980s, when data showed that a test dose was ineffective in predicting subsequent fatal reactions to a full dose of contrast material (11). As needed, postvoid and upright radiographs were obtained.

In 1964, Schencker (12) popularized the technique of drip-infusion pyelography. With this technique, 150 mL of 50%–60% (weight-to-volume ratio) standard urographic contrast material was diluted with 150 mL of 5% dextrose and water. The resultant 300-mL mixture was infused as rapidly as possible through an 18-gauge needle. Radiographs were routinely obtained after one-half of the infusion (half bottle) and the end of the infusion (full bottle). The technique was touted as a method to achieve better opacification of both the renal parenchyma and the collecting system because Schencker believed the addition of the dextrose solution promoted a diuresis that would distend the collecting system with contrast material. Tomography of the kidney was often added to the technique (13).

The infusion technique lost favor when Cattell et al (14) demonstrated that the peak plasma concentration of the contrast material was the single most important factor in determining the degree of renal opacification achieved for a given level of renal function. They also showed that the peak plasma concentration of contrast material was lower with the infusion technique than with standard bolus administration for an equal dose of contrast material.

In the early part of the decade, nephrotomography (15) was not routinely performed as part of the IVU. It was performed as a separate study the next day if the IVU image or retrograde pyelogram suggested that a renal parenchymal mass was present. After a scout tomogram was obtained, a large dose of contrast material (150 mL) was injected rapidly through one or two large-bore intravenous catheters while 5-mm-thick tomographic sections of the kidney in both the anteroposterior and oblique projections were obtained with a 40° tomographic arc. If the mass met the criteria for a simple cyst (16) (smooth margins, thin, imperceptible rim, and the presence of a beak sign at the interface of the mass with the renal parenchyma), no further evaluation was performed.

If the mass did not meet the criteria for a simple cyst, a flush aortogram was obtained with the use of the then recently described Seldinger technique (17) through a 6-F or 7-F catheter. This was followed by a selective renal arteriogram. Catheters were often hand-fashioned from large spools of catheter material. In many cases, 3–5 µg of epinephrine was injected through this catheter just prior to the contrast material to constrict the normal renal arterial supply (18). The tumor vessels theoretically would not constrict, thereby enhancing the detectability of the mass (Fig 2). An inferior vena cavogram and renal venogram were commonly used to assess the extent of tumor involvement in the renal vein if a hypervascular mass was found on the arterial study.

View larger version (97K): [in this window] [in a new window] [Download PPT slide]   Figure 2a. Renal cysts in a 49-year-old woman with vague abdominal pain. (a) Oblique IVU image shows a medial lower pole mass (arrow) displacing and distorting the renal pelvis and lower calices. (b) High-dose bolus nephrotomogram obtained in a steeply oblique position demonstrates the same mass (arrowheads) to be lucent and largely well defined. However, a thin, smooth rim could not unequivocally be demonstrated overlying the contrast material-filled calices (arrows). (c, d) Anteroposterior selective arteriograms, therefore, were obtained that showed the mass to be avascular except for a few tumor vessels (arrowhead in c) suspected medially. (e) Anteroposterior selective arteriogram with epinephrine reveals marked decrease in blood flow to the kidney and no tumor vascularity, which indicates that the lesion is a simple cyst.

View larger version (77K): [in this window] [in a new window] [Download PPT slide]   Figure 2b. Renal cysts in a 49-year-old woman with vague abdominal pain. (a) Oblique IVU image shows a medial lower pole mass (arrow) displacing and distorting the renal pelvis and lower calices. (b) High-dose bolus nephrotomogram obtained in a steeply oblique position demonstrates the same mass (arrowheads) to be lucent and largely well defined. However, a thin, smooth rim could not unequivocally be demonstrated overlying the contrast material-filled calices (arrows). (c, d) Anteroposterior selective arteriograms, therefore, were obtained that showed the mass to be avascular except for a few tumor vessels (arrowhead in c) suspected medially. (e) Anteroposterior selective arteriogram with epinephrine reveals marked decrease in blood flow to the kidney and no tumor vascularity, which indicates that the lesion is a simple cyst.

View larger version (94K): [in this window] [in a new window] [Download PPT slide]   Figure 2c. Renal cysts in a 49-year-old woman with vague abdominal pain. (a) Oblique IVU image shows a medial lower pole mass (arrow) displacing and distorting the renal pelvis and lower calices. (b) High-dose bolus nephrotomogram obtained in a steeply oblique position demonstrates the same mass (arrowheads) to be lucent and largely well defined. However, a thin, smooth rim could not unequivocally be demonstrated overlying the contrast material-filled calices (arrows). (c, d) Anteroposterior selective arteriograms, therefore, were obtained that showed the mass to be avascular except for a few tumor vessels (arrowhead in c) suspected medially. (e) Anteroposterior selective arteriogram with epinephrine reveals marked decrease in blood flow to the kidney and no tumor vascularity, which indicates that the lesion is a simple cyst.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 2d. Renal cysts in a 49-year-old woman with vague abdominal pain. (a) Oblique IVU image shows a medial lower pole mass (arrow) displacing and distorting the renal pelvis and lower calices. (b) High-dose bolus nephrotomogram obtained in a steeply oblique position demonstrates the same mass (arrowheads) to be lucent and largely well defined. However, a thin, smooth rim could not unequivocally be demonstrated overlying the contrast material-filled calices (arrows). (c, d) Anteroposterior selective arteriograms, therefore, were obtained that showed the mass to be avascular except for a few tumor vessels (arrowhead in c) suspected medially. (e) Anteroposterior selective arteriogram with epinephrine reveals marked decrease in blood flow to the kidney and no tumor vascularity, which indicates that the lesion is a simple cyst.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 2e. Renal cysts in a 49-year-old woman with vague abdominal pain. (a) Oblique IVU image shows a medial lower pole mass (arrow) displacing and distorting the renal pelvis and lower calices. (b) High-dose bolus nephrotomogram obtained in a steeply oblique position demonstrates the same mass (arrowheads) to be lucent and largely well defined. However, a thin, smooth rim could not unequivocally be demonstrated overlying the contrast material-filled calices (arrows). (c, d) Anteroposterior selective arteriograms, therefore, were obtained that showed the mass to be avascular except for a few tumor vessels (arrowhead in c) suspected medially. (e) Anteroposterior selective arteriogram with epinephrine reveals marked decrease in blood flow to the kidney and no tumor vascularity, which indicates that the lesion is a simple cyst.

Other techniques available during the 1960s remain essentially unchanged except for relatively minor modifications. These studies include the retrograde pyelogram (Fig 3); the retrograde urethrogram; the cystourethrogram, now obtained without cine fluoroscopy; the cystogram; and the rarely obtained seminal vesiculogram (19), in either retrograde or antegrade (Fig 4) manner through a cutdown on the spermatic cord.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 3a. (a) Anteroposterior retrograde pyelogram demonstrates autosomal dominant polycystic renal disease. The kidneys are enlarged with distorted calices (arrows) that are compressed by multiple intrarenal cysts. An IVU image could not be obtained because the patient had renal failure. (b) Contemporary US image obtained from the extended longitudinal view of the right kidney shows autosomal dominant polycystic renal disease. The cursors denote the length and width of the kidney: 210.4 x 68.6 mm. C = cyst. (c) Transverse computed tomographic (CT) and (d) coronal T1-weighted magnetic resonance (MR) (16/800 [repetition time msec/echo time msec]) images show the cysts (C).

View larger version (107K): [in this window] [in a new window] [Download PPT slide]   Figure 3b. (a) Anteroposterior retrograde pyelogram demonstrates autosomal dominant polycystic renal disease. The kidneys are enlarged with distorted calices (arrows) that are compressed by multiple intrarenal cysts. An IVU image could not be obtained because the patient had renal failure. (b) Contemporary US image obtained from the extended longitudinal view of the right kidney shows autosomal dominant polycystic renal disease. The cursors denote the length and width of the kidney: 210.4 x 68.6 mm. C = cyst. (c) Transverse computed tomographic (CT) and (d) coronal T1-weighted magnetic resonance (MR) (16/800 [repetition time msec/echo time msec]) images show the cysts (C).

View larger version (110K): [in this window] [in a new window] [Download PPT slide]   Figure 3c. (a) Anteroposterior retrograde pyelogram demonstrates autosomal dominant polycystic renal disease. The kidneys are enlarged with distorted calices (arrows) that are compressed by multiple intrarenal cysts. An IVU image could not be obtained because the patient had renal failure. (b) Contemporary US image obtained from the extended longitudinal view of the right kidney shows autosomal dominant polycystic renal disease. The cursors denote the length and width of the kidney: 210.4 x 68.6 mm. C = cyst. (c) Transverse computed tomographic (CT) and (d) coronal T1-weighted magnetic resonance (MR) (16/800 [repetition time msec/echo time msec]) images show the cysts (C).

View larger version (110K): [in this window] [in a new window] [Download PPT slide]   Figure 3d. (a) Anteroposterior retrograde pyelogram demonstrates autosomal dominant polycystic renal disease. The kidneys are enlarged with distorted calices (arrows) that are compressed by multiple intrarenal cysts. An IVU image could not be obtained because the patient had renal failure. (b) Contemporary US image obtained from the extended longitudinal view of the right kidney shows autosomal dominant polycystic renal disease. The cursors denote the length and width of the kidney: 210.4 x 68.6 mm. C = cyst. (c) Transverse computed tomographic (CT) and (d) coronal T1-weighted magnetic resonance (MR) (16/800 [repetition time msec/echo time msec]) images show the cysts (C).

View larger version (117K): [in this window] [in a new window] [Download PPT slide]   Figure 4. Normal seminal vesiculogram. The anteroposterior antegrade image was obtained by means of cutdown on the vas deferens in the scrotum and demonstrates a moderate amount of extravasation of contrast material at the injection site.

View larger version (120K): [in this window] [in a new window] [Download PPT slide]   Figure 5. Anteroposterior retroperitoneal pneumogram following injection of intravenous contrast material demonstrates a normal adrenal gland (A).

View larger version (146K): [in this window] [in a new window] [Download PPT slide]   Figure 6. Anteroposterior abdominal aortogram shows a large adrenal tumor in a 51-year-old man. The tumor is demonstrated by bowing of the inferior adrenal artery (arrowheads). The arrow points to abnormally enlarged tumor vessels within the mass.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 7a. Large right upper pole renal cyst in a 57-year-old man not appreciated on (a) a routine anteroposterior IVU image but readily seen on (b) an anteroposterior tomogram. (c) Double-contrast cyst puncture radiograph obtained cross-table with the patient in the lateral prone position shows the walls to be smooth (arrows in b and c). The layer between the contrast material and the air (A) is normal cyst fluid.

View larger version (108K): [in this window] [in a new window] [Download PPT slide]   Figure 7b. Large right upper pole renal cyst in a 57-year-old man not appreciated on (a) a routine anteroposterior IVU image but readily seen on (b) an anteroposterior tomogram. (c) Double-contrast cyst puncture radiograph obtained cross-table with the patient in the lateral prone position shows the walls to be smooth (arrows in b and c). The layer between the contrast material and the air (A) is normal cyst fluid.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 7c. Large right upper pole renal cyst in a 57-year-old man not appreciated on (a) a routine anteroposterior IVU image but readily seen on (b) an anteroposterior tomogram. (c) Double-contrast cyst puncture radiograph obtained cross-table with the patient in the lateral prone position shows the walls to be smooth (arrows in b and c). The layer between the contrast material and the air (A) is normal cyst fluid.

The Anger gamma camera replaced the rectilinear scanner, and with it came technetium-based isotopes, including Tc-diethylenetriamine pentaacetic acid and Tc-dimercaptosuccinic acid (22,23). The advantages of these technetium compounds included a much shorter half-life and a photopeak more favorable for imaging so that both renal anatomy and renal function could be evaluated.

A-mode ultrasonography (US) was replaced by B-mode US (24). Initially performed with analog scan converters and a compound articulated arm scanning with either white- or black-background scans (Fig 8), black-background real-time US became standard toward the end of the decade. The fast digital scan converter replaced the slower analog variety (25). US rapidly became the imaging study of choice for differentiating solid from cystic renal lesions and displaced nephrotomography and arteriography as the second-line renal imaging study for the evaluation of renal masses.

View larger version (175K): [in this window] [in a new window] [Download PPT slide]   Figure 8. Coronal B-mode longitudinal US scan of the left kidney obtained by using black on a white background shows a renal cyst (C). Note the anechoic nature of the lesion and its enhanced back wall.

The 1980s
Originally developed in the 1970s (29), CT was to go rapidly through three generations of modifications with ever increasing speed and ever decreasing section thickness. By the early 1980s, it had become the imaging study of choice for diagnosing and staging renal cell carcinoma. Some radiologists advocated substituting a CT study for US if a lesion seen at IVU was not likely to be a simple cyst. They felt that CT was easier to perform and less operator dependent and could be used to both diagnose and stage renal cell carcinoma with one examination.

Both nonenhanced and enhanced CT were performed at 1-cm intervals, except in imaging for smaller lesions in which 0.5-cm section intervals were used. An inferior vena cavogram was still recommended if the inferior vena cava could not be determined to be free of tumor at CT, but an arteriographic road map as a preoperative measure in patients with renal cell carcinoma quickly became an anachronism. Soon after CT became accepted as the imaging study of choice for diagnosing and staging renal cell carcinoma (Fig 9), the value of CT was reported for diagnosing angiomyolipomas (Fig 10) and renal inflammatory disease (30–32) and for evaluating renal trauma (33,34).

View larger version (169K): [in this window] [in a new window] [Download PPT slide]   Figure 9a. Early generation transverse CT scans of renal cell carcinoma. (a) Transverse image shows a large tumor mass (M) is present in the right kidney with extension into the right renal vein and inferior vena cava (arrow). (b) Transverse CT scan in a different patient shows a left renal cell carcinoma with extension (arrow) through the renal capsule and Gerota fascia.

View larger version (143K): [in this window] [in a new window] [Download PPT slide]   Figure 9b. Early generation transverse CT scans of renal cell carcinoma. (a) Transverse image shows a large tumor mass (M) is present in the right kidney with extension into the right renal vein and inferior vena cava (arrow). (b) Transverse CT scan in a different patient shows a left renal cell carcinoma with extension (arrow) through the renal capsule and Gerota fascia.

View larger version (174K): [in this window] [in a new window] [Download PPT slide]   Figure 10. Early generation transverse CT image demonstrates angiomyolipoma. The lesion (T) arising from the ventral aspect of the right kidney has virtually the same attenuation as that of the retroperitoneal fat, which indicates its true nature.

By the early 1980s, however, second-generation nonionic compounds that were stable in solution were introduced into clinical practice (37,38). Although much better tolerated than conventional ionic contrast materials, the new contrast materials generated immediate controversy because they were 20–30-fold more expensive than the existing ionic contrast materials.

By the late 1980s, MR imaging started to become more readily available throughout the United States (39–42). Although still too expensive and too slow for routine use, it replaced inferior vena cavography as the study of choice to evaluate the inferior vena cava for staging renal cell carcinoma when CT results were inconclusive. It also was used in patients with sensitivity to iodinated contrast material and patients with abnormal renal function. With the advent of gadopentetate dimeglumine, a reliable, safe contrast material to demonstrate flow to the kidney became available for MR imaging.

Real-time gray-scale US (43) replaced compound B-mode scanning and became progressively better for the evaluation of not only the orthotopic kidney but also the transplanted kidney, the prostate, the bladder, and the testis. CT became extremely valuable in evaluating lymph node metastases from kidney, bladder, and testis tumors and obviated lymphangiography.

Although the technique of percutaneous nephrostomy was initially described in 1955 (44), it was not until the late 1970s (45) and early 1980s that it became firmly established as the procedure of choice to establish upper urinary tract drainage with radiologic guidance. By the middle of the 1980s, however, the role of percutaneous nephrostomy and that of the interventional uroradiologist was greatly expanded through the development of the technique of nephrostolithotomy (46–48). In this procedure, a radiologist working with a urologist inserted a large-bore tract into the collecting system so that a renal calculus could be seen with a rigid nephroscope and fragmented by means of ultrasonic lithotripsy.

These techniques revolutionized the treatment of renal stone disease and led to the development of a wide variety of additional percutaneous transrenal urologic interventional procedures performed through the nephroscope or with fluoroscopic guidance. Urologists who specialized in the performance of endoscopic procedures formed a new urologic subspecialty known as endourology.

The 1990s
As the last decade of the century opened, the issue of selective versus universal use of nonionic contrast material came to the fore. The landmark Katayama et al study (49), performed in Japan, concerning the safety of ionic and nonionic contrast materials was published. The study results clearly showed that "severe" and "very severe" adverse reactions to nonionic contrast material were approximately sixfold less frequent than with ionic contrast materials. However, whether the prevalence of fatal reactions was also less frequent was more controversial.

In Europe and Canada, nonionic contrast materials quickly became the agents of choice, since the price differential was lower and the cost of nonionic contrast material was borne by nationalized health care programs. Cost continued to militate against a policy of universal use of nonionic agents in many institutions in the United States. Although some institutions shifted completely to nonionic contrast materials for all intravenous use, others limited the use of nonionic agents to patients at high risk for an adverse reaction and required that their use be justified on a written form. Fortunately, by 1999 the price of the nonionic contrast material had dropped to only two to three times greater than that of ionic contrast materials, and the controversy had diminished greatly.

In the early part of the decade, cross-sectional imaging studies had already begun to replace the IVU as the primary renal imaging technique. In 1975, an estimated 10,000,000 urograms were obtained annually in the United States; just 20 years later, the number of IVUs had dropped to about 600,000 per year (50). Thus, the concept of abdominal imaging was born, as the cross-sectional techniques depicted all of the organs of the abdomen at a single examination. One consequence was that more and more renal masses were discovered as incidental findings on imaging studies performed for nonurinary indications.

Although the presence of an adrenal mass was readily diagnosed at CT since its inception, methods by which adrenal metastases and adenomas could be differentiated awaited the discovery that most adenomas contained a large amount of intracellular lipid and, thus, typically had lower attenuation coefficients than metastatic or primary adrenal tumors. If the attenuation of an adrenal mass was less than 15 HU at nonenhanced CT, Korobkin and co-workers (51) from the University of Michigan showed that the lesion could be considered to be an adenoma. If only an enhanced CT scan was obtained, a delayed set of images at 15 minutes, 30 minutes, or 1 hour following the enhanced study would demonstrate a rapid washout of contrast material, which results in an attenuation close to baseline if the lesion is an adenoma (52) (Fig 11). In-phase and out-of-phase MR imaging to demonstrate intracellular lipid also can be performed to establish this diagnosis (53–55) (Fig 12).

View larger version (133K): [in this window] [in a new window] [Download PPT slide]   Figure 11a. Transverse CT scans of a right adrenal adenoma (arrowhead in a and b) in a 63-year-old man with weight loss and asbestos exposure. (a) The CT attenuation during the dynamic phase of contrast enhancement was 29 HU. (b) Fifteen minutes after the injection of contrast material, the attenuation was 8 HU.

View larger version (142K): [in this window] [in a new window] [Download PPT slide]   Figure 11b. Transverse CT scans of a right adrenal adenoma (arrowhead in a and b) in a 63-year-old man with weight loss and asbestos exposure. (a) The CT attenuation during the dynamic phase of contrast enhancement was 29 HU. (b) Fifteen minutes after the injection of contrast material, the attenuation was 8 HU.

View larger version (134K): [in this window] [in a new window] [Download PPT slide]   Figure 12a. Transverse fast multiplanar spoiled gradient-echo MR image of bilateral adrenal adenomas (arrowheads in a and b). Note the loss of signal intensity in the adrenal adenomas compared with the liver on (a) the out-of-phase image (150/1.9) in contrast to (b) the in-phase image (150/4.2).

View larger version (122K): [in this window] [in a new window] [Download PPT slide]   Figure 12b. Transverse fast multiplanar spoiled gradient-echo MR image of bilateral adrenal adenomas (arrowheads in a and b). Note the loss of signal intensity in the adrenal adenomas compared with the liver on (a) the out-of-phase image (150/1.9) in contrast to (b) the in-phase image (150/4.2).

View larger version (154K): [in this window] [in a new window] [Download PPT slide]   Figure 13a. Renal cell carcinoma in a 46-year-old man with acquired immunodeficiency syndrome. Transverse dynamic spiral CT scans obtained in (a) the nephrographic phase and (b) the excretory phase both show the tumor (T). The nephrographic phase shows a normal renal vein (v in a) and more of the inhomogeneous nature of the tumor.

View larger version (150K): [in this window] [in a new window] [Download PPT slide]   Figure 13b. Renal cell carcinoma in a 46-year-old man with acquired immunodeficiency syndrome. Transverse dynamic spiral CT scans obtained in (a) the nephrographic phase and (b) the excretory phase both show the tumor (T). The nephrographic phase shows a normal renal vein (v in a) and more of the inhomogeneous nature of the tumor.

View larger version (133K): [in this window] [in a new window] [Download PPT slide]   Figure 14a. (a) Coronal three-dimensional fast gradient-echo dynamic contrast-enhanced MR angiogram (6/1.3, 45° flip angle) and (b) coronal single-shot fast spin-echo MR urogram (2,047/620, 10-cm section thickness) in a healthy renal donor. Note the excellent demonstration of the main renal arteries bilaterally. The renal veins and inferior vena cava (arrow in a) are also well shown. On the urogram, the collecting systems and ureters, as well as a distended urinary bladder, are well shown.

View larger version (83K): [in this window] [in a new window] [Download PPT slide]   Figure 14b. (a) Coronal three-dimensional fast gradient-echo dynamic contrast-enhanced MR angiogram (6/1.3, 45° flip angle) and (b) coronal single-shot fast spin-echo MR urogram (2,047/620, 10-cm section thickness) in a healthy renal donor. Note the excellent demonstration of the main renal arteries bilaterally. The renal veins and inferior vena cava (arrow in a) are also well shown. On the urogram, the collecting systems and ureters, as well as a distended urinary bladder, are well shown.

View larger version (127K): [in this window] [in a new window] [Download PPT slide]   Figure 15a. Transverse nonenhanced helical CT scans demonstrate acute right ureteral obstruction secondary to a distal ureteral calculus. (a) Image obtained through the middle portion of the kidneys shows dilatation of the right renal pelvis (p) and moderate perinephric stranding (arrow) and edema. (b) The obstructing calculus (arrow) is seen in the right ureterovesical junction.

View larger version (130K): [in this window] [in a new window] [Download PPT slide]   Figure 15b. Transverse nonenhanced helical CT scans demonstrate acute right ureteral obstruction secondary to a distal ureteral calculus. (a) Image obtained through the middle portion of the kidneys shows dilatation of the right renal pelvis (p) and moderate perinephric stranding (arrow) and edema. (b) The obstructing calculus (arrow) is seen in the right ureterovesical junction.

View larger version (126K): [in this window] [in a new window] [Download PPT slide]   Figure 16a. Fistula to the bladder secondary to Crohn disease in a 19-year-old man with hematuria and particulate matter in the urine. (a) Transverse CT scan of the bladder shows a small pocket of air (arrowhead) trapped just beneath the bladder mucosa. (b) Transverse CT scan obtained at a higher level shows the inflamed thickened small bowel (arrowhead).

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 16b. Fistula to the bladder secondary to Crohn disease in a 19-year-old man with hematuria and particulate matter in the urine. (a) Transverse CT scan of the bladder shows a small pocket of air (arrowhead) trapped just beneath the bladder mucosa. (b) Transverse CT scan obtained at a higher level shows the inflamed thickened small bowel (arrowhead).

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 17a. Acute testicular torsion. (a) Transverse color Doppler US image of both the right (R) and left (L) hemiscrotums show absence of perfusion in the left testicle as a result of acute testicular torsion. (b) Coronal color Doppler US image of the left testicle also shows no arterial flow. (c) Coronal color Doppler US image of the right testicle (T) is normal.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 17b. Acute testicular torsion. (a) Transverse color Doppler US image of both the right (R) and left (L) hemiscrotums show absence of perfusion in the left testicle as a result of acute testicular torsion. (b) Coronal color Doppler US image of the left testicle also shows no arterial flow. (c) Coronal color Doppler US image of the right testicle (T) is normal.

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 17c. Acute testicular torsion. (a) Transverse color Doppler US image of both the right (R) and left (L) hemiscrotums show absence of perfusion in the left testicle as a result of acute testicular torsion. (b) Coronal color Doppler US image of the left testicle also shows no arterial flow. (c) Coronal color Doppler US image of the right testicle (T) is normal.

View larger version (162K): [in this window] [in a new window] [Download PPT slide]   Figure 18a. Chronic testicular torsion in a 29-year-old man with 2-3 days of testicular pain. (a) Anteroposterior delayed nuclear medicine scan obtained with the use of technetium 99m diethylenetriamine pentaacetic acid shows absence of uptake in the testicle with increased flow to the scrotal skin (arrow). (b) Transverse power Doppler US image also demonstrates absence of perfusion in the testicle itself, with a rim (arrows) of peripheral hyperemia. (c) Transverse gray-scale US image shows inhomogeneity in the testis (T), which is indicative of infarction. Cursors denote the overall size of the testis to be 20.5 x 32.3 mm.

View larger version (162K): [in this window] [in a new window] [Download PPT slide]   Figure 18b. Chronic testicular torsion in a 29-year-old man with 2-3 days of testicular pain. (a) Anteroposterior delayed nuclear medicine scan obtained with the use of technetium 99m diethylenetriamine pentaacetic acid shows absence of uptake in the testicle with increased flow to the scrotal skin (arrow). (b) Transverse power Doppler US image also demonstrates absence of perfusion in the testicle itself, with a rim (arrows) of peripheral hyperemia. (c) Transverse gray-scale US image shows inhomogeneity in the testis (T), which is indicative of infarction. Cursors denote the overall size of the testis to be 20.5 x 32.3 mm.

View larger version (172K): [in this window] [in a new window] [Download PPT slide]   Figure 18c. Chronic testicular torsion in a 29-year-old man with 2-3 days of testicular pain. (a) Anteroposterior delayed nuclear medicine scan obtained with the use of technetium 99m diethylenetriamine pentaacetic acid shows absence of uptake in the testicle with increased flow to the scrotal skin (arrow). (b) Transverse power Doppler US image also demonstrates absence of perfusion in the testicle itself, with a rim (arrows) of peripheral hyperemia. (c) Transverse gray-scale US image shows inhomogeneity in the testis (T), which is indicative of infarction. Cursors denote the overall size of the testis to be 20.5 x 32.3 mm.

The New Millennium
As we enter the new millennium, multidetector spiral CT scanners with the ability to complete a study in less than 20 seconds and to rescan immediately, if necessary, are becoming available. With increased computing power, three-dimensional reconstructions in any plane and from any projection will be available.

A new examination, CT urography, combining the cross-sectional imaging features of CT with the spatial resolution of radiography, is being proposed as the examination of choice for the evaluation of hematuria (66). This examination combines conventional radiographs or digital images of the kidneys with cross-sectional CT images obtained both before and after the administration of contrast material in place of conventional planar tomography. A consensus of precisely how such a study should be performed has yet to be achieved but is the subject of ongoing research. A committee sponsored by the Society of Uroradiology has undertaken the task of making recommendations in this regard. Similarly, MR urography is also being explored (67,68).

As cross-sectional imaging techniques have become the first-line imaging studies in both the gastrointestinal and genitourinary systems and have replaced older organ-specific examinations, there has been continued evolution in both the teaching and practice of these subspecialties. The Accreditation Council on Graduate Medical Education, or ACGME, has approved the creation of abdominal imaging fellowships, as stand-alone fellowships in either gastrointestinal or genitourinary radiology are virtually nonexistent, and the Society of Gastrointestinal Radiologists and the Society of Uroradiology will jointly cosponsor a postgraduate course in abdominal radiology early in 2000.

GYNECOLOGIC IMAGING

Prior to the advent of US, gynecologic imaging was limited to radiographic evaluation of dystrophic pelvic calcifications in uterine leiomyomas and to the recognition of teethlike calcifications and fat in ovarian dermoid cysts (Fig 19). In addition, soft-tissue masses in the pelvis could be recognized, as could the displacement of normal urinary or gastrointestinal structures on either urographic or barium gastrointestinal studies. Pneumograms obtained after the intraperitoneal injection of air or carbon dioxide were occasionally used to evaluate gynecologic masses (69) (Fig 20).

View larger version (149K): [in this window] [in a new window] [Download PPT slide]   Figure 19. Anteroposterior upright radiograph from an IVU shows a dermoid cyst of the ovary. Note the characteristic teethlike calcification (arrowhead) in the dermoid cyst. Pelvic floor relaxation is present as an incidental finding.

View larger version (101K): [in this window] [in a new window] [Download PPT slide]   Figure 20. Posteroanterior pelvic pneumogram shows polycystic ovaries. This image was obtained by injecting air or carbon dioxide intraperitoneally. The patient was then tilted with the head down in the prone position. In so doing, the rising air or carbon dioxide outlined the enlarged ovaries (O) and the normal-sized uterus (U). The bladder (B) is seen, as is the bowel.

During the 1960s, the radiographic evaluation of a pelvic mass continued to be IVU followed by a barium enema examination (Fig 21). These were usually performed on the same day. This was followed by an upper gastrointestinal series and small-bowel follow-through examination. Chain cystourethrography was advocated as a method for classifying stress urinary incontinence according to the method of Green (71) (Fig 22). Today, such studies have been abandoned in favor of more sophisticated videourodynamic studies in which images are combined with physiologic information obtained during voiding to characterize more precisely the cause of the incontinence. Cystourethrography and double-balloon retrograde urethrography were used to examine female patients suspected of having diverticula of the urethra, although in many instances such lesions could be diagnosed on a postvoid radiograph from an IVU. Diverticula of the urethra also may be imaged by means of cross-sectional techniques.

View larger version (138K): [in this window] [in a new window] [Download PPT slide]   Figure 21a. Bilateral invasive ovarian cancer in a 74-year-old woman. (a) Anteroposterior IVU image shows a large mass (M) of soft-tissue arising from the pelvis and partially obstructing the right ureter. R = right. (b) Anteroposterior image obtained during barium enema examination performed the same day shows elevation of a redundant sigmoid colon on the left side (arrowhead). On the right side, the mass separates and lifts the cecum and distal ileum (solid arrow) and compresses the sigmoid colon (open arrow). (c) Transverse CT scan shows an extensive invasive mass (M).

View larger version (131K): [in this window] [in a new window] [Download PPT slide]   Figure 21b. Bilateral invasive ovarian cancer in a 74-year-old woman. (a) Anteroposterior IVU image shows a large mass (M) of soft-tissue arising from the pelvis and partially obstructing the right ureter. R = right. (b) Anteroposterior image obtained during barium enema examination performed the same day shows elevation of a redundant sigmoid colon on the left side (arrowhead). On the right side, the mass separates and lifts the cecum and distal ileum (solid arrow) and compresses the sigmoid colon (open arrow). (c) Transverse CT scan shows an extensive invasive mass (M).

View larger version (134K): [in this window] [in a new window] [Download PPT slide]   Figure 21c. Bilateral invasive ovarian cancer in a 74-year-old woman. (a) Anteroposterior IVU image shows a large mass (M) of soft-tissue arising from the pelvis and partially obstructing the right ureter. R = right. (b) Anteroposterior image obtained during barium enema examination performed the same day shows elevation of a redundant sigmoid colon on the left side (arrowhead). On the right side, the mass separates and lifts the cecum and distal ileum (solid arrow) and compresses the sigmoid colon (open arrow). (c) Transverse CT scan shows an extensive invasive mass (M).

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 22. Chain cystourethrogram for evaluation of stress urinary incontinence. Sagittal image of the bladder from the lateral view was obtained after insertion of a copper chain into the urethra and bladder. The chain allows demonstration of the urethrovesical angles when the patient strains, the measurement of which constitutes the major criterion for classifying stress incontinence according to Green (71).

View larger version (160K): [in this window] [in a new window] [Download PPT slide]   Figure 23. Coronal endovaginal hysterosonogram demonstrates a large endometrial polyp (arrow).

The development of gynecologic imaging as a new specialty within radiology has mirrored the tremendous change within the specialty of uroradiology during the past 3 decades. Initially limited to traditional urologic imaging by means of organ-specific radiographic techniques, the uroradiologist's sphere now includes imaging of the accessory sexual organs in the male patient; imaging of the female pelvic organs; and, in some centers, urologic intervention. The emergence of cross-sectional imaging as the dominant modality for evaluating the urogenital system has also blurred the traditional distinction between gastrointestinal and genitourinary radiology. A new amalgamation, abdominal radiology, with roots in both subspecialties, has emerged and has replaced traditional genitourinary and gastrointestinal sections in many academic departments. The need for organ-specific knowledge and teaching, however, has not changed. The challenge for the new generation of genitourinary radiologists, trained predominantly in cross-sectional techniques, will be to maintain the close interaction with clinical colleagues that the traditional organ system–based imaging techniques fostered.

Footnotes

²_**. Entire organ system or region

Abbreviation: IVU = intravenous urography

References

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