Philip J. Kenney

Imaging of adrenal masses.

Adrenal pathology may be discussed based on hormonal functionality of the adrenals, appearances on imaging modality, or pathological determination. There are three main categories of adrenal function. Hyperfunctional states include Conns or Cushings syndrome. Lesions with normal function may be detected incidentally. Hypofunctional states may occur from idiopathic Addisons disease or some bilateral adrenal pathology. The most common modalities for characterization of adrenal pathology are non-enhanced CT, often followed by contrast CT or chemical shift MRI. The common appearance on non-enhanced CT is a well-defined homogeneous lesion with low-density due to the microscopic fat present and adrenal adenomas. When density criteria are not met, many of these may be characterized as adenomas by washed out of contrast or signal decrease using in phase and out-of-phase MRI sequences. Other non-invasive modalities may incidentally discover adrenal lesions, but are not typically used in the work-up. NP-59 is an uncommonly used nuclear medicine technique which is very specific for adenoma when correlated with pathology on other imaging studies. In the rare cases where non-invasive imaging is non-specific, fine needle aspiration or core biopsies may be necessary. However, biopsies have associated risks including infection and hemorrhage. The imaging appearance of an adrenal lesion is often specific such that further imaging is not necessary. These lesions include adrenal adenoma, pheochromocytoma, myelolipoma, adrenal cyst, and some large adrenocortical carcinomas. However, the findings in lesions such as metastasis, smaller primary adrenal carcinomas, lymphoma, granulomatous disease, and many adenomas are not as specific. In the proper clinical situation, follow-up imaging may be necessary, or biopsy may be warranted.

Imaging of renal trauma

Trauma is a major cause of death and disability and renal injuries occur in up to 10% of patients with significant blunt abdominal trauma. Patients with penetrating trauma and hematuria, blunt trauma with shock and hematuria, or gross hematuria warrant imaging of the urinary tract specifically and CT is the preferred modality. If there is significant perinephric fluid, especially medially, or deep laceration, delayed images should be obtained to evaluate for urinary extravasation. Most renal injuries are minor, including contusions, subcapsular and perinephric hematoma, and superficial lacerations. More significant injuries include deep lacerations, shattered kidney, active hemorrhage, infarctions, and vascular pedicle and UPJ injuries. These injuries are more likely to need surgery or have delayed complications but may still often be managed conservatively. The presence of urinary extravasation and large devitalized areas of renal parenchyma, especially with associated injuries of intraperitoneal organs, is particularly prone to complication and usually requires surgery. Active hemorrhage should be recognized because it often indicates a need for urgent surgery or embolization to prevent exsanguination.

Computed Tomography of Ureteral Disruption

Computed tomography in four cases of urine extravasation due to ureteropelvic disruption secondary to blunt trauma were compared with CT in 15 cases of renal parenchymal injury. In three cases of isolated ureteropelvic disruption the renal parenchyma was intact; contrast medium excretion was normal; no perirenal hematoma was present. Contrast medium extravasation was confined predominantly to the medial perirenal space. The ipsilateral ureter was not opacified in three of the four cases of ureteropelvic disruption. These CT findings of ureteral injury are distinct from those of renal parenchymal injury. When these findings are present on CT done for trauma, confident diagnosis of ureteral disruption can be made. In one case, combined renal parenchymal injury and ureteropelvic disruption occurred.

CT and MR imaging in the evaluation of retroperitoneal fibrosis.

We have performed CT and MR on five patients with biopsy proven retroperitoneal fibrosis (RPF). Magnetic resonance (MR) accurately displayed a retroperitoneal mass of low signal intensity on T1-weighted scans and of heterogeneous medium signal intensity on T2-weighted scans. The coronal MR views demonstrated a retroperitoneal mass: the shape, signal intensity, and effects on the ureters and major vessels appear characteristic of RPF.

CT evaluation of urinary lithiasis

Unenhanced CT has been demonstrated to be the most accurate and efficient diagnostic imaging means to evaluate urinary lithiasis, with capability of directing management, and has become well accepted by radiologists, urologists, and emergency department physicians such that it is now the standard of practice. It is the duty of the radiologist to be aware of proper technique and the details of interpretation. The radiologist also has a duty to be aware of the limitations of unenhanced CT for detection and evaluation of various nonstone disorders, particularly with poor patient selection, and to extend the examination if appropriate. Controversies and future developments include cost containment with care for the selection of patients. Further attempts to reduce radiation exposure should be made. Optimal CT technique is not needed in general merely to detect urinary lithiasis. A consensus should be developed regarding use of CT in pregnant patients. Further improvements in the digital scout view would be useful for following patients.

LIVE DONOR NEPHRECTOMY IN PATIENTS WITH FIBROMUSCULAR DYSPLASIA OF THE RENAL ARTERIES

PURPOSE We determine the suitability of patients with fibromuscular dysplasia of the renal arteries as renal donors. MATERIALS AND METHODS We evaluated 37 patients with fibromuscular dysplasia who were potential renal donors. Renal artery lesions were graded I (mild) to IV (severe). Of the patients 19 underwent donor nephrectomy and 18 were rejected as donors. Reasons for rejection included severity of disease or availability of a better donor. Nephrectomy was performed on the side with fibromuscular dysplasia when disease was unilateral or on the side with more advanced disease when the lesions were bilateral. Patients were followed at 1 month, 1 year and then yearly. RESULTS Of the 19 patients undergoing donor nephrectomy serum creatinine increased by a mean of 0.4 mg./dl. (range 0.1 to 1.1) on postoperative day 1. Effective renal plasma flow of the remaining kidney increased by 25% on postoperative day 5 and by 29% after 1 year. After a mean followup of 4.5 years no patient had hypertension, proteinuria or any significant change in serum creatinine compared to baseline values. Of the 18 patients not undergoing nephrectomy 11 were contacted at a mean followup of 4 years, and none had hypertension, proteinuria or abnormal serum creatinine. CONCLUSIONS Patients with fibromuscular dysplasia may be acceptable renal donors. The decision to use a patient with fibromuscular dysplasia as a donor is based on patient age, the availability of other suitable donors, and the extent and severity of disease.

Calcified adrenal masses

We reviewed 106 cases of adrenal masses of all types in all age groups. Thirty-three contained calcium visible on radiographs, sonography, or computed tomography (CT). Neuroblastoma was the most common calcified adrenal mass (10 cases), and occurred only in children. Adrenal cyst (6 cases) was the most common calcified adrenal mass in adults. Other calcified adrenal masses included 5 cortical adenomas, 4 adrenal carcinomas, 3 cases of adrenal hemorrhage, 2 adrenal metastases, 2 pheochromocytomas, and 1 histoplasmoma. Calcification within an adrenal mass is therefore nonspecific. All the adrenal cysts had a characteristic radiographic pattern, showing only peripheral curvilinear calcification. The presence and pattern of calcium in an adrenal mass must be correlated with other imaging features (e.g., size, homogeneity, enhancement pattern, margination) to allow correct differential diagnosis. This can best be done by CT.

Computed tomographic diagnosis of ectopic ureter with seminal vesicle cyst

A rare case of dysplastic kidney with ectopic ureter entering a cystic seminal vesical is reported. This demonstrates the usefulness of computerized tomography in noninvasively delineating such anomalies. Thus accurate preoperative diagnosis can be done, aiding in surgical planning.

Computed tomography of ureteral tumors

Ten patients with one or more ureteral tumors were examined with CT. The tumor was clearly recognizable as a soft tissue mass (average density 46 HU) filling the ureter in nine of the patients. In five of these patients the tumor was not detected by urography. Tumors less than 5 mm in diameter were missed on CT in one patient. Although most ureteral tumors are detectable with urography and retrograde pyelography, CT can be a valuable diagnostic tool. Computed tomography is particularly advantageous in patients with nonfunctioning kidneys and in those in whom retrograde pyelography is unsuccessful.

Magnetic resonance imaging of the adrenal gland in women with late-onset adrenal hyperplasia

To determine the presence of structural abnormalities of the adrenal in late-onset adrenal hyperplasia, four consecutive patients were studied by MRI before beginning glucocorticoid replacement therapy. Three women were diagnosed as 21-hydroxylase deficient late-onset adrenal hyperplasia by a 17-OHP level greater than 1,000 ng/dL 30 minutes after acute adrenal stimulation, and one patient was diagnosed as 11-hydroxylase deficient late-onset adrenal hyperplasia when her 11-deoxycortisol level was threefold the upper 95th percentile of normal. Two patients with 21-hydroxylase deficient late-onset adrenal hyperplasia had normal adrenal glands on MRI. Another 21-hydroxylase deficient late-onset adrenal hyperplasia patient was noted to have a 2.5 x 3.3-cm left adrenal nodule, which had been documented some 4 years earlier on CT scan and had not changed in size during that interval. This patient was 40 years of age when the diagnosis of late-onset adrenal hyperplasia was established. The patient with 11-hydroxylase deficient late-onset adrenal hyperplasia demonstrated a diffuse enlargement of the left adrenal gland consistent with hyperplasia, with no focal lesions. In conclusion, although patients with late-onset adrenal hyperplasia may often demonstrate nodular or diffuse adrenocortical hyperplasia on MRI, not all patients with endocrinologically evident disease demonstrate such abnormalities, consistent with a lesser degree of ACTH stimulation compared with women with classical congenital adrenal hyperplasia.