Imaging approach to staging of renal cell carcinoma.

Current imaging techniques, especially CT and MR imaging, make accurate preoperative staging of renal cell carcinoma possible. Because surgery provides the only effective therapy and because survival depends on local and distant extent, precise staging is critical for preoperative planning and prognosis. This article reviews the advantages, limitations, accuracy, and pitfalls of each of the imaging approaches to staging renal cell carcinoma, concentrating on CT and MR imaging. This information then is summarized in a suggested overall approach to staging renal cell carcinoma.

The role of imaging in staging renal adenocarcinoma.

Numerous surgical options are available to physicians treating patients with renal adenocarcinoma. In the current clinical setting, imaging plays a key role in determining which options are selected. Newer imaging techniques such as helical CT with CT angiography, MRI, and ultrasound (US) have improved staging capabilities in this patient population. However, to approach staging accuracies recently reported, attention must be paid to proper imaging parameters. This article describes the strengths, limitations, and proper techniques used for staging renal adenocarcinoma with CT, MRI, and US.

CT diagnosis of acute flank pain from urolithiasis.

The use of noncontrast helical CT (NHCT) to assess patients with acute flank pain and hematuria for potential urinary tract stone disease was first reported in 1995. After several years of experience with the technique, sensitivity and specificity of NHCT has proven to be better than intravenous urography for evaluating ureteral stones. NHCT imaging findings for urinary calculi and the differential diagnosis are discussed in this article. Various extraurinary diseases found while using NHCT in searching for stone disease are addressed and illustrated. As experience with the use of NHCT has increased, clinicians have broadened the indications for this technique, which has a lower charge than standard CT, beyond the specific evaluation of urinary colic. This indication creep has increased the number of NHCT examinations ordered. It has also reduced the rate of stone positivity and increased the diagnostic yield for extraurinary disease.

Computed tomography evaluation of colorectal carcinoma.

Knowledge of the extent of primary colorectal carcinoma at initial diagnosis is critical for proper management of disease. Currently, CT does not have a role in screening for colorectal carcinoma, though promising work on virtual colonoscopy is on the horizon. In patients with proven colorectal carcinoma, accurate prospective noninvasive assessment can identify those who may benefit from preoperative local radiotherapy, hepatic resection or cryoablation, or intra-arterial chemotherapy. CT should be considered complementary to the clinical assessment of colorectal carcinoma and to other modalities, such as barium enema, endorectal ultrasonography, MRI, and immunoscintigraphy. Although limited in evaluation of the primary tumor and local spread, CT has proven useful in assessing patients thought to harbor extensive local or metastatic disease. CT is generally the modality of choice for imaging the postoperative patient. The cross-sectional display of CT clearly depicts the operative bed, particularly after abdominoperineal resection. Baseline examinations should be obtained 2 to 4 months after surgery, with follow-up examinations every 6 to 9 months for 2 years, and yearly studies thereafter. CT-guided biopsies should be performed when findings suggest recurrent carcinoma.

Magnetic resonance imaging of pediatric hip disease.

The efficacy of magnetic resonance imaging (MRI) in the assessment of pediatric hip disease was tested by scanning the hips of 24 children (30 scans). Twelve patients with Legg-Calvé-Perthes disease (17 hips) showed characteristic areas of low-intensity signal representative of necrotic areas of the capital epiphysis. Abnormal scans were also obtained on patients with transient synovitis, avascular necrosis secondary to steroids, epiphyseal dysplasia, and multiple osteochondromatosis. MRI accurately shows articular cartilage, femoral head shape, quality of containment, and areas of necrosis in pediatric hips. The extent of involvement and revascularization can be identified in Legg-Calvé-Perthes disease.

MR appearance of sternal hyperostosis.

Sternal hyperostosis is characterized by prominent new bone formation and fibrosis with less pronounced areas of granulation tissue and round cell infiltration. In previously reported cases the process involved not only the sternum but adjacent bony areas as well. Depending upon the extent of disease, acquiring biopsy material for histologic analysis can be difficult. We report a case of sternal hyperostosis involving the sternum exclusively and extensively. Magnetic resonance imaging was useful in directing biopsy for optimal histologic yield. This unusual case of sternal hyperostosis is believed to be the result of an inflammatory process.

Staging of renal adenocarcinoma: role of various imaging procedures.

Since the only successful curative treatment of renal adenocarcinoma is surgery, accurate radiologic information is crucial during initial tumor staging for optimal operative planning. Accurate radiologic staging can be achieved by use of proper imaging techniques, usually a combination of contrast-enhanced CT or multiplanar MR imaging with fast scanning techniques. These techniques permit the demonstration of regional lymph nodes, vascular extension, and distant metastases. Sonography and inferior venacavography are used occasionally to supplement the information obtained from CT or MR imaging. We review the principles of staging of renal adenocarcinoma, emphasizing the strengths and weaknesses of each imaging technique.

Renal sinus histiocytosis.

A 26-year-old woman had an infiltrative renal lesion accompanied by massive regional lymphadenopathy. Biopsy of the renal mass and a coexistent orbital mass revealed identical histologic evidence of sinus histiocytosis. This unusual benign entity is uncommon in the kidney, but radiographically, it may closely simulate an infiltrative renal neoplasm, especially a lymphoma or leukemia or even renal cell carcinoma.

Prolonged hepatic enhancement on computed tomography in a case of hepatic lymphoma.

Hepatic lymphoma is often very difficult to detect using any modality. A case of hepatic lymphoma appeared on rapid contrast infused CT as extremely prolonged and bizarre enhancement. The specific features included a widespread and aggressive appearance with a variable pattern of contrast enhancement. There was one localized area of apparent centripetal accumulation of contrast medium. The prolonged and irregular enhancement may be due to contrast medium "trapping" in interstitial spaces or even to the fact that a bolus technique was used.

Superior vena caval obstruction: detection using CT.

A review of 210 chest computed tomographic (CT) examinations demonstrating upper chest masses revealed 16 cases of superior vena caval obstruction (SVCO); 11 of these were clinically occult. Two of the occult cases subsequently became clinically evident. Contrast-enhanced chest CT permits the diagnosis of clinically occult SVCO and should be considered in patients with upper chest masses, even in the absence of any physical signs of SVCO.

Postoperative computed tomographic evaluation of congenital hip dislocation.

The use of computed tomography (CT) in the postoperative evaluation of 19 congenitally dislocated hips is presented so that appropriate indications for reduction can be determined and radiologic criteria can be defined for judging whether reduction is satisfactory. The radiologic technique is presented. CT is an accurate and cost-effective modality that is capable of demonstrating subtle changes in femoral head position.

Blunt upper abdominal trauma: evaluation by CT.

CT is the technique of choice for initial examination of hemodynamically stable patients after blunt abdominal trauma. It is highly sensitive, specific, and accurate for use in detecting the presence or absence of injury and defining its extent. Nonoperative management of many posttraumatic injuries, particularly in the liver, spleen, and kidney, is possible in part because of the diagnostic usefulness of CT. CT can be used effectively to visualize the progression of liver and spleen injuries in those patients chosen for conservative management. CT helps in treatment decisions in patients with renal injury by defining the character and extent and distinguishing minor from severe renal trauma. Posttraumatic injuries to the pancrease, bowel, and mesentery can be detected with CT. In these areas, however, signs may be subtle, and a significant injury may be missed on an initial examination.

Evaluation of PACS in ultrasonography.

We review our experience with a picture archiving and communication system to replace film in the ultrasound section of a clinical radiology department. The system includes three ultrasound units connected by a fiberoptic network via acquisition nodes to a central data management system, workstation, and optical jukebox. The system handles 80% of sonographic studies in the department. Image production, interpretation, storage, and retrieval are evaluated. Despite limitations, a picture archiving and communication system can be integrated into a functioning ultrasound section of an active radiology department with minimal disruption and promising results.

CT appearance of disseminated peritoneal adenomucinosis.

Disseminated peritoneal adenomucinosis (DPAM) is a relatively rare cause of pseudomyxoma peritonei, marked by peritoneal lesions with abundant extracellular mucin and little cytologic atypia among exfoliated tumor cells, and usually associated with appendiceal adenomas. Peritoneal mucinous carcinomatosis (PMCA) also causes diffuse peritoneal tumor but is marked by neoplastic mucinous epithelium with cytologic features of carcinoma and associated with appendiceal, colon, gastric, or small bowel carcinoma. Compared with PMCA, DPAM has a different distribution of disease and a significantly better prognosis. DPAM is characterized by the lack of lymph node involvement, with primarily superficial peritoneal involvement, and a relatively benign, relapsing course over many years. Dominant primary masses may not be evident in DPAM. Despite considerable overlap in the two main causes of pseudomyxoma peritonei, there are features of the two that may help differentiate between them. We present the computed tomographic appearance of DPAM in a series of seven cases and emphasize characteristics of the disease.

MR imaging of anterior cruciate ligament repair.

Magnetic resonance (MR) imaging is an accurate means of analyzing disruptions of the native anterior cruciate ligament (ACL). Various techniques may be used to repair a disrupted ACL. A common repair is the MacIntosh lateral-substitution over-the-top repair in which a strip of fascia lata from the iliotibial band is used as a "neoligament." The results of 27 MR examinations of 17 athletes with this repair were analyzed to determine the appearance of the neoligament on MR. Thirteen of the 17 patients had returned to full athletic activity and four were capable of strenuous activity. Examinations were made at both 0.5 and 1.5 T in varied extents of external rotation from 0 to 20 degrees, and at variable time intervals after surgery from 1 to nearly 40 months. Only two patients clinically required postrepair arthroscopy, but both had normal repairs. Neoligaments were classified as well-defined (n = 6 studies), ill-defined (n = 10), and not discernible (n = 11), based on clarity of appearance. Reasons for this variable appearance include the variable presence of fibrous and fatty tissue investing the neoligament. We conclude that the normal neoligament, unlike the normal active ACL, has a variable appearance, including nonvisualization on MR and that criteria used in evaluating the native ligament will be inadequate to assess the repair.

The perirenal space: relationship of pathologic processes to normal retroperitoneal anatomy.

The perirenal space may be involved by disease processes that arise within or outside the perirenal space. Key anatomic details that dictate the features of perirenal processes include the renal capsule, the perirenal septa, the renal fascia, and the conic shape and inferomedial orientation of the perirenal space. Superiorly, the perirenal space is open to the bare area of the liver. The perirenal spaces communicate with one another at the level of the lower lumbar vertebrae. The hallmark of perirenal infection is localized or diffuse gas. Chronic urinoma appears as an encapsulated cystic mass, often aligned parallel with the perirenal space. Fat within an apparent spontaneous hematoma of the perirenal space suggests angiomyolipoma. Renal cell carcinoma, lymphoma, and melanoma are the most common causes of discrete solid masses in the perirenal space; metastases occur due to the characteristic lymphatic and vascular supply of the space. Amyloidosis and fibrosis create a nonspecific rind of soft tissue around the kidneys. Diaphragmatic pseudotumor produces a linear "lesion" in the perirenal space.

Relationship between mammographic features and hormone receptor content in patients with breast cancer.

Recurrences of breast cancer are more responsive to hormone therapy if the tumors are positive for estrogen receptors or progesterone receptors. To assess the relationship between hormone receptor content, mammographic tumor morphology, and breast parenchymal patterns, we reviewed charts and mammograms of 210 patients with primary unilateral breast cancer. Mammograms of tumors in 97 patients were divided morphologically into five groups: (1) spiculated mass, (2) architectural distortion, (3) calcifications only, (4) circumscribed mass, and (5) tumor not visible. Estrogen receptor positivity was 81% (39/48) in group 1, 37% (7/19) in group 2, 17% (2/12) in group 3, 31% (4/13) in group 4, and 60% (3/5) in group 5 (P less than .001). Mean estrogen receptor content was also significantly different among groups (P less than .001). There was no statistically significant association between tumor morphology and progesterone receptors, or between calcifications and receptor status. In all 210 patients, hormone-receptor-positive tumors showed no association with mammographic parenchymal pattern. When direct assay of estrogen receptors is unavailable, mammographic appearance of the tumor may suggest the estrogen receptor status.

Recurrent colorectal carcinoma: evaluation with barium enema examination and CT.

The efficacy of the barium enema examination and abdominal computed tomography (CT) was investigated in 81 patients who had undergone operation for colorectal carcinoma. Recurrent disease was found in 52 patients and was divided into local (anastomotic and perianastomotic) and remote (distant and hepatic metastases) types. In 32 patients with locally recurrent carcinoma, the sensitivity of the barium enema examination was 88%; for CT it was 69%. Conversely, the barium enema examination was not useful for detecting remote metastases shown on CT, which disclosed disease at one or more sites in 47 (90%) of the 52 patients. CT best evaluated recurrences remote from the anastomosis, pelvic recurrences in patients with colostomies, and hepatic metastases. Barium enema examination and CT were therefore found to be complementary modalities.

Is it necessary to biopsy the obvious?

OBJECTIVE: The radiologist and oncologist are often confident that biopsy will confirm their suspicion of recurrent disease, but a biopsy is performed to confirm the histologic diagnosis before beginning or altering therapy. We have examined data to determine how often the biopsied lesion represents recurrent disease from the primary tumor or is an instance of new cancer, and whether recurrent disease can be predicted. MATERIALS AND METHODS: We reviewed the medical and imaging records of 253 patients who underwent CT-guided biopsy of an abdominal or pelvic lesion between 1993 and 1996. Sixty-nine of the 253 patients had a previously diagnosed primary tumor and were being examined for possible tumor recurrence or metastasis. The images of these 69 patients were analyzed to determine if the pattern of disease was typical of recurrence or metastasis. RESULTS: In 55 of the 69 patients, the pattern was judged to be typical of metastatic or recurrent disease. Biopsy confirmed this suspicion in all 55 patients. In 14 of the 69 patients, the pattern of spread was judged not to be typical of recurrence or metastasis. These 14 patients were found to have a new primary tumor (n = 4), benign processes (n = 2), and recurrences (n = 8). CONCLUSION: Of the patients for whom radiographic findings suggested recurrence, we found no patients in whom a new primary tumor would have been missed if biopsy had been avoided. Data should now be acquired prospectively to determine whether it may be prudent to make treatment decisions on the basis of imaging findings alone, without histologic confirmation.

The CT nephrogram: implications for evaluation of urinary tract disease.

The urographic nephrogram is an important indicator of underlying functional and structural renal disease. With expansions in use of cross-sectional imaging, the computed tomographic (CT) nephrogram (ie, contrast material enhancement within the renal parenchyma) has assumed a greater role in the evaluation of urinary tract disorders. Both quantitative and qualitative nephrographic abnormalities are well demonstrated by CT, including global or segmental absence or persistence of the nephrogram, slowed temporal progression, striated pattern, and rim pattern. Global absence is nearly always unilateral and is most often seen with blunt abdominal trauma with renal pedicle injury. Segmental absence is attributable to focal renal infarction, most likely due to arterial emboli. Global persistence, which is much more common than segmental persistence, may be unilateral (caused by renal artery stenosis, renal vein thrombosis, or urinary tract obstruction) or bilateral (due to systemic hypotension, intratubular obstruction, or abnormalities in tubular function). Striated nephrograms may be unilateral or bilateral and are caused by ureteric obstruction, acute pyelonephritis, contusion, renal vein thrombosis, tubular obstruction, hypotension, and autosomal recessive polycystic kidney disease. The rim pattern is most often associated with renal infarction and occasionally with acute tubular necrosis and renal vein thrombosis. Careful evaluation of the CT nephrogram is an integral part of the abdominal CT examination.