A prospective study of factors predicting clinically occult spinal cord compression in patients with metastatic prostate carcinoma.

BACKGROUND: The objective of this study was to identify clinical parameters that predict occult subarachnoid space or spinal cord (SAS/SC) compression, as determined by magnetic resonance imaging (MRI), in patients with metastatic prostate carcinoma. METHODS: A prospective study was performed in which 68 patients with bone metastases from prostate carcinoma and a normal neurologic examination underwent MRI of the entire spine after documentation of clinical, X-ray, and bone scan parameters potentially predictive of occult SAS/SC compression. RESULTS: Occult SAS/SC compression was diagnosed in 22 patients (32%) using MRI. Nine patients (13%) had compressions at two discontinuous spinal levels. Extensive disease on bone scan, the duration of continuous hormonal therapy prior to study entry, and hemoglobin concentration were found to predict SAS/SC compression by univariate analysis. The extent of disease on bone scan and the duration of continuous hormonal therapy were independent predictors of SAS/SC compression by multivariate analysis (P = 0.02 and P = 0.04, respectively). The risk of occult SAS/SC compression increased from 32% to 44% in patients with a bone scan that showed > 20 metastases as the duration on hormones increased from 0 to 24 months. The risk in patients with fewer metastases increased from 11% to 17% over the same interval. The presence or absence of back pain was not predictive of SAS/SC compression. CONCLUSIONS: Patients who are at high risk for occult SAS/SC compression can be identified using clinical parameters and readily available diagnostic tests. These high-risk patients should undergo MRI screening with the aim of diagnosing and treating spinal cord compression before the development of neurologic deficits that may be irreversible.

Unusual eustachian tube mass: glomus tympanicum.

SUMMARY: A case of recurrent glomus tympanicum presenting with epistaxis is described. CT and MR imaging revealed a homogeneously enhancing mass extending along the entire course of the eustachian tube, with a portion protruding into the nasopharynx. Glomus tumors tend to spread along the path of least resistance and may extend into the eustachian tube. The unique imaging appearance should place a glomus tumor high on the list of differential diagnoses.

Magnetic resonance imaging (MRI) for localization of the prostatic apex: comparison to computed tomography (CT) and urethrography.

BACKGROUND AND PURPOSE: It is necessary to include the entire prostate in the high dose treatment volume when planning radical radiation for patients with prostate cancer. We prospectively compared magnetic resonance imaging (MRI) to computed tomography (CT) and urethrography as means of localizing the prostatic apex. MATERIALS AND METHODS: Thirty patients with clinically localized prostate cancer had a sagittal T2-weighted MRI scan and a conventional axial CT scan performed in the treatment position prior to the start of radiotherapy. Twenty of these patients had a static retrograde urethrogram performed at simulation. The position of the MRI and CT apices were localized independently by two radiation oncologists. In addition, the MRI apex was localized independently by a diagnostic radiologist. The urethrogram apex, defined as the tip of the urethral contrast cone, was easily identified and was therefore localized by only one observer. RESULTS: There was good interobserver agreement in the position of the MRI apex. Interobserver agreement was significantly better with MRI than with CT. There were no systematic differences in the position of the MRI and CT apices. However, the MRI apex was located significantly above and behind the urethrogram apex. There was poor correlation between MRI and CT and between MRI and urethrogram in the height of the apex above the ischial tuberosities. There was 83% agreement between MRI and CT and 80% agreement between MRI and urethrogram in the identification of patients with a low-lying apex. The apex, as determined by MRI, was <2 cm above the ischial tuberosities and therefore potentially under-treated in 17% of the patients. CONCLUSIONS: MRI is superior to CT and urethrography for localization of the prostatic apex. All patients undergoing radiotherapy for prostate cancer should have localization of the apex using MRI or a technique of equal precision to assure adequate dose delivery to the entire prostate and to minimize the unnecessary irradiation of normal tissues.

Gadolinium-based MR contrast media: potential for growth of microbial contaminants when single vials are used for multiple patients.

OBJECTIVE: To assess potential risk if single-dose vials of gadolinium-based contrast media are used for multiple patients. The use of multidose vials can pose a significant risk if contaminants are accidentally introduced into the vials and proliferate. Therefore, we tested the ability of gadolinium-based contrast to support the growth of a variety of microbial pathogens. MATERIALS AND METHODS: We collected the unused portions of 15 single-use vials of gadolinium-based contrast media. The residual contrast material was refrigerated after use and checked for sterility prior to inoculation with a selection of gram-positive and gram-negative bacteria and yeast. Contrast material was incubated at room temperature and at 4 degrees C, and quantitative cultures were performed at 0, 24, 48, and 72 hr and at 7 days. RESULTS: No microbial growth occurred from cultures of the used contrast solutions prior to inoculation. None of the organisms tested in our study proliferated in the contrast material. All test organisms persisted at least 48 hr after inoculation at both temperatures. At 7 days, Staphylococcus aureus, Streptococcus epidermidis, and Corynebacterium jeikeium were recovered in significant quantities. Colony counts of Serratia odorifera rapidly decreased at room temperature but persisted beyond 7 days at 4 degrees C. CONCLUSION: The risk of contaminating vials of contrast agents punctured aseptically is small. Our study demonstrates a lack of proliferation of organisms in the two gadolinium-based compounds tested, suggesting that these solutions could be used for more than one procedure.

Parenchymal patterns of the breast defined by real time ultrasound.

The association of mammographic parenchymal patterns of the breast with breast cancer risk has been studied extensively but there is little information about the distribution of different patterns in populations at different risks for breast cancer. Such information could be obtained if a risk-free method of breast examination were available that could be applied to the general population. We have evaluated real time ultrasound for this application by comparing the parenchymal pattern as assessed by mammography with the extent of echogenicity in the breast on ultrasound examination in 102 subjects. Subjects were examined by both methods, the mammographic and ultrasound images independently classified, and the proportion of the breast occupied by radiological density or ductal prominence compared with the extent of echogenic areas on ultrasound. These two methods of classifying mammographic parenchymal patterns were found to be strongly correlated. Real time ultrasound may therefore be useful in the epidemiological study of mammographic pattern and breast cancer risk.

Magnetic resonance imaging in preoperative localization of diseased parathyroid glands: a comparison with isotope scanning and ultrasonography.

The value of magnetic resonance imaging (MRI) in the preoperative localization of parathyroid glands was assessed through a comparison of the findings with those obtained by ultrasonography and isotope scanning. The localization findings in 37 patients with primary hyperparathyroidism were compared with the operative findings. The sensitivities of the three modalities as defined by the ability to detect a parathyroid adenoma were 67% (isotope scanning), 44% (ultrasonography) and 36% (MRI). The differences were not significant. The sensitivities as defined by the ability to predict the correct side of the lesion were 48% (isotope scanning) 33% (ultrasonography) and 36% (MRI). No correlation was found between the sensitivity of a given localization test and factors such as the presence of thyroid abnormalities, size of the lesion, type of lesion and preoperative calcium and parathormone levels. The low sensitivity and high cost of all three preoperative localization studies render them unnecessary in the management of uncomplicated parathyroid disease. However, if preoperative imaging is necessary, ultrasonography and isotope scanning are recommended, since MRI was not found to be superior.

Surveillance after orchidectomy for patients with clinical stage I nonseminomatous testis tumors.

PURPOSE: This study was designed to determine the proportion of patients with clinical stage I nonseminomatous germ cell tumors of the testis (NSGCTT) managed with surveillance after orchidectomy who have more advanced disease and, therefore, require further treatment, the time to progression, the sites of progression, and the efficacy of treatment delayed until progression was recognized. PATIENTS AND METHODS: One hundred five patients were observed prospectively without further treatment after orchidectomy and full clinical staging. Treatment was given immediately upon detection of marker-positive, clinical, or radiologic evidence of disease. RESULTS: Thirty-seven patients (35.2%) have required further therapy for disease progression, occurring from 2 to 21 months after diagnosis. Thirty-six patients have been successfully treated. Overall, 104 patients (99%) remain alive and free of disease at 12 to 121 months after orchidectomy. Progression occurred in the retroperitoneum in 25 of 37 patients who developed further disease on surveillance. The presence of vascular invasion in the primary tumor was predictive of an increased risk of progression. CONCLUSION: Surveillance is a valid alternative to immediate retroperitoneal lymph node dissection in patients with clinical stage I NSGCTT but should be recommended only under the close supervision of physicians experienced in the diagnosis and treatment of testicular cancer.

Magnetic resonance imaging of the mediastinum.

Seven normal volunteers and 69 patients with known disease in either the mediastinum or hila or both were imaged using a prototype magnetic resonance imager operating at 0.15T. Normal mediastinal and hilar structures were readily identified and mediastinal diseases were well demonstrated by magnetic resonance imaging (MRI). The value of MRI lies in the morphological demonstration of the presence and extent of disease.

Primary radiation therapy for juvenile nasopharyngeal angiofibroma.

Evidence is presented of the effectiveness and relative lack of serious toxicity of external beam megavoltage radiation therapy (RT) as primary treatment for juvenile nasopharyngeal angiofibroma. The importance of careful radiological evaluation of tumor extent prior to irradiation is stressed, and only moderate dose RT is required. Fifty-five patients have been treated by RT and followed for from 3 to 26 years. Forty-four of 55 patients (80%) had permanent tumor control following a single course of 3000 cGy to 3500 cGy over 3 weeks. Surgical resection or a second course of RT controlled the tumor in all 11 patients in whom regrowth occurred. Angiofibromas involute slowly after RT so that 50% of patients still had visible masses in the nasopharynx 12 months after treatment, but only 10% had any visible abnormality 36 months after RT. Retreatment was necessary only if symptoms recurred, and continued follow-up showed that most asymptomatic nasopharyngeal masses resolved completely. Acute and late toxicity rates were low. Two patients developed tumors in the head or neck following RT. There was no significant clinical impairment of growth or endocrine function. A single course of external beam megavoltage radiation to 3000 cGy in 3 weeks is an effective first treatment for patients with juvenile nasopharyngeal angiofibroma.

Efficacy of computed tomography in the management of cancer patients.

An evaluation was made of 1030 computed tomography (CT) scans performed on cancer patients. Seventy percent of the scans taken were of the pelvis, abdomen, or thorax. Both referring clinicians and radiologists rated the diagnostic and management efficacy of each scan using a simple scale of values. Over 50% of the scans provided unique diagnostic information: 39% resulted in a change in diagnosis or in known extent of disease; and 14% led to a change in patient management. The fraction of abnormal results was not a reliable measure of efficacy. Specific groups of patients were identified, which demonstrated that both diagnostic and management efficacy should be measured in assessing the value of CT as a diagnostic modality.