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1.
OBJECTIVE: This study was performed to compare two proposed algorithms used when evaluating an adrenal mass discovered during staging evaluation of a patient with a known malignancy. Such evaluation was meant to lead to determination of the relative charges associated with each algorithm. SUBJECTS AND METHODS: Fifty-four patients with known malignancies who required evaluation of an adrenal mass underwent both chemical shift imaging (CSI) and CT-guided for CSI. The hospital charges incurred for each procedure and any associated complications were normalized using national relative-value scale charges and conversion factors. A decision analysis was performed to compare the relative charges that would have been incurred if adrenal MR imaging had been performed in all patients, followed by CT-guided biopsy only in those patients with MR findings not diagnostic of adrenocortical adenoma, and the relative charges incurred if only CT-guided adrenal biopsy had been performed in every patient. RESULTS: Twenty-three (43%) of 54 adrenal masses were shown to be metastases by CT-guided biopsy. The sensitivity and specificity of CSI for the diagnosis of adrenocortical adenoma were 94% and 100%, respectively. The charges incurred by performing MR imaging as the initial examination with subsequent CT-guided biopsy only in those patients with CSI findings not diagnostic of adenoma would have been similar to those incurred by first performing CT-guided adrenal biopsy in every patient. CONCLUSION: CSI is an accurate, noninvasive technique for evaluating adrenal masses in patients with cancer. If CT-guided biopsy is used only when CSI is not diagnostic of adrenocortical adenoma, the associated charges would be virtually the same as when CT-guided biopsy is performed as the first test in every patient. Moreover, biopsies could have been avoided in 54% of these patients.  相似文献   

2.
Complex physiologic and neoplastic processes affect the adrenal glands. An appreciation of the gross pathologic and histologic correlates of disease aids in understanding the mechanisms by which diagnostic imaging helps characterize adrenal masses. Computed tomographic (CT) densitometry and chemical shift magnetic resonance (MR) imaging would seem to be the most reliable tools in determining whether a given adrenal mass is specifically an adenoma. Such a determination is made on the basis of the presence of substantial amounts of intracytoplasmic lipid. Thus, although a homogeneous mass with a CT attenuation of less than 10 HU or a decrease in signal intensity at opposed-phase MR imaging is diagnostic for adenoma, lesions that do not have these features are indeterminate and may necessitate biopsy. Adrenal myelolipoma also has a distinctive imaging appearance that reflects the presence of macroscopic fat deposits. Diagnosis of adenoma or adrenal myelolipoma is very helpful in the assessment and treatment of asymptomatic patients with adrenal masses and may make biopsy unnecessary. In patients with clinical or biochemical evidence of adrenal disease, MR imaging helps confirm the presence of a mass and allows localization and further characterization of the lesion.  相似文献   

3.
PURPOSE: To evaluate the magnetic resonance (MR) imaging findings in collision tumors of the adrenal gland. MATERIALS AND METHODS: MR images obtained in 104 patients with a known primary malignant tumor and an adrenal mass were reviewed to find adrenal glands that contained two contiguous but histologically distinct masses. The findings in such cases were correlated with histopathologic findings. RESULTS: In two (2%) cases, both MR and histopathologic findings showed a mass within the adrenal gland that consisted of contiguous adrenal adenoma and metastasis, which represented a collision tumor. The adenomatous component in each tumor showed a (quantitative) decrease in signal intensity relative to that of the liver (79% and 61%) on opposed-phase images, whereas the metastatic component showed an increase in signal intensity (50% and 15%). Similarly, the adrenal lesion-to-spleen signal intensity ratio on opposed-phase images was lower for the adenomatous component in each (0.39 and 0.43) than for the metastatic component (1.17 and 0.90). CONCLUSION: MR imaging can demonstrate and enable characterization of the separate components of collision tumors within the adrenal gland. These findings can be crucial in planning and guiding subsequent percutaneous needle biopsy and patient care.  相似文献   

4.
PURPOSE: To evaluate routine non-contrast material-enhanced helical computed tomography (CT) of the adrenal glands in patients with non-small cell lung carcinoma to facilitate characterization of adrenal masses detected in an unmonitored environment (i.e., the radiologist on duty did not look at the acquired images before the patient left the scanner). MATERIALS AND METHODS: One hundred consecutive patients with non-small cell lung carcinoma were referred for CT evaluation of the chest; chest and abdomen; or chest, abdomen, and brain. All underwent unenhanced CT of the adrenal glands before the requested CT examination. The morphologic features, size, and attenuation values of the adrenal masses were calculated. Attenuation values of adrenal masses from prior imaging, if available, were compared with those at follow-up imaging to classify these masses. Variable unit cost increase in obtaining these additional images was estimated. RESULTS: Fifteen adrenal masses were identified in 13 patients. In one patient, bilateral ill-defined adrenal masses were present. In 12 patients, 13 masses were sharply circumscribed: Seven were less than 10 HU and six were 20 HU or greater at unenhanced CT. Nine of these 12 patients received iodinated contrast material. Without the unenhanced CT, 10 adrenal masses in these nine patients would have been indeterminate for malignancy. In six of these nine patients, the adrenal mass was the only potential site of metastatic disease. The unenhanced CT data helped classify three of these masses as benign-10 HU or less- and three as indeterminate-greater than 10 HU. CONCLUSION: Unenhanced CT of the adrenal glands can prospectively characterize adrenal masses and obviate further examination in patients with lung carcinoma.  相似文献   

5.
PURPOSE: The aims of this study were 1) to report the characteristics and the clinical outcome of familial adenomatous polyposis (FAP) patients with adrenal masses in the FAP registry at the Cleveland Clinic Foundation and 2) to estimate the prevalence of adrenal masses detected by computed tomography in FAP patients compared with that expected in a normal population. METHODS: A retrospective review was undertaken of the FAP registry database at our institution. Only 738 patients treated at the Cleveland Clinic Foundation were included in the study. A meta-analysis was conducted to determine the relative risk of adrenal incidentaloma in this series of FAP patients and in a general population as reported in the four largest pertinent studies published in the past 15 years. RESULTS: Fifteen patients (11 females) were identified. Two patients had symptoms related to cortisol hypersecretion (arterial hypertension) and underwent surgery. The final pathology was adrenocortical carcinoma and bilateral nodular hyperplasia. Adrenal masses were found incidentally (incidentalomas) in 13 patients: 12 were detected by computed tomography and one during laparotomy for total abdominal colectomy. Only one patient underwent left adrenalectomy for a 5-cm mass. Pathologic report revealed adrenocortical adenoma. Among the 738 patients considered in this study, only 162 underwent abdominal computed tomographic scan, mainly for assessing intra-abdominal desmoid. The prevalence of incidentaloma in our series compared with that reported in the literature is significantly different (7.4 vs. 0.6-3.4 percent; P < 0.001 (chi-squared test)). DISCUSSION: Although the presence of other extracolonic manifestations represents a selection bias for computed tomographic study in our series, the incidence of incidentalomas in FAP patients seems to be higher than in a general population. However, incidental detection of an adrenal mass in FAP patients has probably a limited clinical relevance, and the management should be the same as that for the normal population.  相似文献   

6.
Primary hyperaldosteronism (PHA) represents less than 1 to 2% of all causes of hypertension (HT). We report 2 cases of primary hyperaldosteronism which emphasize the difficulty of distinguishing neoplastic PHA from idiopathic PHA, observed in a 60-year-old woman and a 42-year old woman, respectively. In both cases, the diagnosis of PHA was suggested by marked hypokalaemia with inappropriate potassium excretion and was confirmed by hyperaldosteronaemia and low and poorly stimulated renin activity. In the first case, computed tomography showed nodular hyperplasia of the 2 adrenal glands. The patient was treated with spironolactone and calcium channel blockers which controlled blood pressure and serum potassium. In the second case, computed tomography and magnetic resonance imaging revealed an adrenocortical adenoma confirmed by pathological examination after the operation. The diagnosis of primary hyperaldosteronism is based on three steps: detection, positive diagnosis and aetiological diagnosis. Detection is essentially based on demonstration of hypokalaemia. Positive diagnosis is based on demonstration of elevated aldosterone secretion with inhibited renin secretion. The aetiological diagnosis is dominated by the differentiation between Conn's adenoma and bilateral adrenal hyperplasia, which has therapeutic implications.  相似文献   

7.
BACKGROUND: When an asymptomatic adrenal mass is incidentally discovered on abdominal CT scans, the distinction between a nonhyperfunctioning adenoma and a nonadenoma would be important. METHODS: We evaluated the CT findings of 36 adrenal masses (14 nonhyperfunctioning adenomas, 22 nonadenomas) in 34 patients with no evidence of hormonal hypersecretion. CT attenuation values of adrenal masses on CT scans were calculated by setting a circular region of interest as large as possible in the center of each adrenal mass. RESULTS: Below 20 HU in CT attenuation values, all adrenal masses, except one case of ganglioneuroma with myxomatous change, were nonhyperfunctioning adenomas. With an arbitrary threshold of 20 HU, the sensitivity of CT attenuation values in distinguishing nonhyperfunctioning adenomas from nonadenomas was 64%, the specificity was 95%, and the accuracy was 83%. When decreasing the threshold to 15 HU, the sensitivity was 64%, the specificity was 100%, and the accuracy was 86%. The CT attenuation value on noncontrast CT was more useful for making this distinction than the size and interior homogeneity. CONCLUSIONS: Our data suggest that an asymptomatic adrenal mass with homogeneous low attenuation (< or = 15 HU) and less than or equal to 4 cm indicates a nonhyperfunctioning adenoma, and no further examinations are necessary. CT attenuation value on non-contrast CT is the most important discriminatory factor.  相似文献   

8.
To date, magnetic resonance (MR) is established as an imaging modality in the diagnosis of chest diseases. Because of its excellent distinction of vessels and soft tissue, MR can be performed as the primary imaging procedure before computed tomography in patients with suspected vascular lesions, mediastinal masses, hilar lesions, and pathological changes of the pleura and the chest wall. In these cases, MR is able to provide all the necessary diagnostic information. In other patients, a limited number of MR images may be helpful in cases of equivocal or confusing CT or clinical findings. More detailed information can be obtained, using surface coils or special imaging sequences, i.e. high resolution MR images of the pleura or angiographic images of mediastinal and pulmonary vasculature. From a clinical viewpoint, the most important task for thoracic magnetic resonance nowadays is the pretherapeutic evaluation of intrathoracic masses, the differential diagnosis of benign versus malignant lesions, and the accurate documentation of tumour extent in malignancies including three-dimensional-display to improve surgical or radiation planning. Future directions in thoracic magnetic resonance will be predominantly influenced by postprocessing approaches, specialized imaging techniques, and magnetic resonance-guided interventional applications.  相似文献   

9.
PURPOSE: To assess whether magnetic resonance (MR) spectroscopic imaging with MR imaging can improve prostate cancer localization in postbiopsy hemorrhage cases. MATERIALS AND METHODS: Records of 175 patients with prostate cancer were retrospectively reviewed; 42 patients (135 hemorrhagic sites) had spatially correlated biopsy data. Patients underwent both phased-array coil-endorectal coil MR imaging and three-dimensional MR spectroscopic imaging within 180 days after transrectal ultrasound (US)-guided biopsy. High-signal-intensity hemorrhage on T1-weighted images and corresponding high- or low-signal-intensity areas on T2-weighted images and the metabolic ratio (choline + creatine)/citrate were recorded. Cancer was identified as a low-signal-intensity area at T2-weighted MR imaging or a metabolite ratio greater than 3 standard deviations above normal at MR spectroscopic imaging. MR imaging, spectroscopic, and biopsy findings were compared. RESULTS: Forty-nine patients had postbiopsy hemorrhage. On T2-weighted images, a higher (P < .01) percentage of hemorrhagic sites demonstrated low signal intensity (80% [108 of 135 sites]), which is similar to the signal intensity seen with cancer. The addition of MR spectroscopic imaging to MR imaging resulted in a significant increase (P < .01) in the accuracy (52% to 75%) and specificity (26% to 66%) of tumor detection. CONCLUSION: The addition of MR spectroscopic imaging to MR imaging significantly improves the ability to determine the presence of prostate cancer and spatial extent when postbiopsy changes hinder interpretation with MR imaging alone.  相似文献   

10.
BACKGROUND: The purpose of our study was to determine the incidence and locations of M1 disease at presentation in patients with non-small cell lung cancer to help design appropriate preoperative imaging algorithms. METHODS: All patients with non-small cell lung cancer seen between 1991 and 1993 were identified, and records were reviewed. For patients with M1 disease, the sites of distant metastases and the methods of diagnosis were recorded. RESULTS: Of 348 patients identified, 276 (79%) had M0 disease and 72 (21%) had M1 disease. In 40 of 72 patients (56%), M1 disease was detected via chest or abdominal computed tomography (CT). Brain, bone, liver, and adrenal glands were the most common sites of metastatic disease, in decreasing order. Brain metastases often occurred as an isolated finding, although isolated liver metastases were uncommon. CONCLUSIONS: M1 disease was common at presentation, and was often detectable via chest CT. The incremental yield of abdominal CT over chest CT was very small, and therefore abdominal CT is not an effective method of screening for metastases if chest CT has been performed.  相似文献   

11.
The authors study the ultrasound signs of the adrenal gland based on 5 different types of operated adrenal tumours (a lipoma, an adrenal cortical adenoma, a cyst, a corticoadrenaloma, an adrenal metastasis from a renal cell carcinoma). The ultrasonographic morphological criteria of the normal adrenal gland and each type of tumour are recalled and are illustrated by clinical cases. The value of ultrasonography in the investigation of this organ was evaluated in comparison with other imaging techniques. It constitutes a good first-line diagnostic guiding examination, but needs to be completed by other investigations (computed tomography, magnetic resonance imaging, etc.). Ultrasonography can also reveal asymptomatic adrenal tumours ("adrenal incidentalomas") in which the therapeutic decision (surveillance or surgery) must be based on criteria of size and appearance after a complete laboratory and morphological assessment.  相似文献   

12.
M Rubin  K Horiuchi  N Joy  W Haun  R Read  E Ratzer  M Fenoglio 《Canadian Metallurgical Quarterly》1997,174(6):694-6; discussion 697-8
BACKGROUND: Palpable breast tumors have traditionally been diagnosed with open biopsy or core biopsy. We propose fine needle aspiration biopsy (FNA) as a reliable, cost-saving initial procedure in these patients. METHODS: Eighty-five palpable solid breast masses of the breast in 85 patients were classified by a combination of physical examination, mammography, and/or ultrasound as probably benign, indeterminate, or highly suspicious for cancer. All tumors had FNA biopsies. All patients had either a confirmatory open biopsy (55) or close clinical follow-up (30) with a mean follow-up of 29 months (range 6 to 36). RESULTS: Thirty-four patients classified as clinically benign had a benign FNA biopsy. No cancers were detected in this group by either open surgical biopsy or clinical follow-up. Twenty patients were classified clinically as indeterminate. All had FNA biopsies, and 6 were either positive for cancer or suspicious for cancer. Fourteen patients had negative FNA biopsies. Five of the 6 abnormal biopsies had cancer on open biopsies. The 1 false-positive result occurred in a lactating patient. Thirty-one patients were classified clinically as highly suspicious for cancer. Twenty-three were confirmed as cancer with FNA biopsy. Eight needed open surgical biopsy to confirm cancer. All 31 patients clinically suspicious for cancer had cancer. In patients classified clinically as highly suspicious or probably benign, FNA was a reliable first diagnostic step (100% positive predictive value, 100% specificity, 87% sensitivity, and 89% negative predictive value). CONCLUSIONS: Fine needle aspiration biopsy of solid palpable breast lesions should be the diagnostic procedure of choice for those patients classified clinically as probably benign or clinically as highly suspicious for cancer. Cost analysis revealed elimination of an open biopsy in such cases would save $1,100 per patient. For highly suspicious cases, a negative fine needle aspiration should not deter an open surgical biopsy. For patients classified as indeterminate, fine needle aspiration biopsy results are not reliable enough to determine treatment.  相似文献   

13.
The evaluation of mediastinal lymph nodes is an important aspect of staging in patients with non-small cell lung cancer. Anatomic imaging of lymph nodes with computed tomography (CT) and magnetic resonance (MR) imaging has been limited by the relatively low sensitivity and specificity of these techniques. Advances in physiologic imaging of mediastinal lymph nodes with 2-[fluorine-18] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) have resulted in improved diagnostic accuracy in the determination of nodal status. Despite the limitations of CT, this technique still plays an important role by aiding in the selection of the most appropriate procedure for staging, by guiding biopsy, and by providing anatomic information for visual correlation with FDG PET images. At present, anatomic MR imaging of lymph nodes is primarily a problem-solving tool for cases with inconclusive CT results. Physiologic MR imaging with iron oxide is an exciting area of investigation, and the accuracy of this technique is being assessed in clinical trials. Anatomic and physiologic imaging techniques should be considered complementary rather than competitive imaging strategies.  相似文献   

14.
STUDY OBJECTIVE: To assess the potential health and cost effects of initial testing with sputum cytology to diagnose lung cancer. DESIGN: Cost-effectiveness analysis. DATA SOURCES: Surveillance Epidemiology and End Results (SEER) program; cost data from Northern California Kaiser Permanente Hospitals and Universities of Stanford and Iowa; National Center for Health Statistics; and a MEDLINE search. INTERVENTIONS: The use of sputum cytologies preceding other tests (ie, fine-needle aspiration, bronchoscopy, thoracoscopy) in patients with suspected lung cancer. MAIN OUTCOME MEASURES: Mortality associated with testing and initial surgical treatment (eg, performance of thoracoscopy to remove a local-stage, centrally located cancer), cost of testing and initial treatment, life expectancy, lifetime cost of medical care, and cost-effectiveness. RESULTS: In central lesions, sputum cytology as the first test was the dominant strategy because it both lowers medical-care costs ($2,516 per patient) and lowers the mortality risk (19 deaths in 100,000 patients) of the evaluation without adversely affecting long-term survival. In peripheral lesions, sputum cytology costs less then $25,000 per year of life saved if the pretest probability of cancer exceeds 50%. The estimated annual savings of adopting sputum cytology as the first test for diagnosing lung cancer in the United States is at least $30 million. CONCLUSIONS: Experience in regional centers indicates that sputum cytologic testing is infrequently ordered before implementing invasive diagnostic techniques, even in patients with central lung masses. The study findings suggest that sputum cytology as the first test in suspected lung cancer is likely to be cost saving without adversely affecting patient outcomes.  相似文献   

15.
OBJECTIVE: To investigate the feasibility, safety and results of laparoscopic transperitoneal adrenalectomies performed with the patient supine, in patients affected by secreting and silent adrenal lesions. METHODS: Exclusion criteria were suspected adrenal primary malignancies. Fifty patients (33 women and 17 men; mean age 49.6 years, range 19-75 years) underwent 51 laparoscopic adrenalectomies (one bilateral). After complete endocrinological evaluation, computed tomography or magnetic resonance imaging, or a combination thereof, 14 non-secreting adenomas, 13 aldosterone-producing adenomas, 13 cortisol-producing adenomas, eight phaeochromocytomas (one bilateral), one androgen-secreting adenoma, and two metastases were considered eligible for adrenalectomy. In five patients, associated procedures were performed during surgery. RESULTS: The lesions ranged in size from 1.5 to 10 cm. There were no intraoperative complications and no blood transfusions were required. The postoperative course was uneventful and painless in all patients. Mean postoperative hospital stay was 2.5 days. In all hypertensive patients, significant improvement or cure of hypertension was observed at follow-up (mean 18 months). In patients with secreting adenomas, normalization of hormone concentrations was obtained after removal of the tumour. In six patients with incidentaloma, the exaggerated 17-hydroxyprogesterone response to ACTH disappeared after surgery. CONCLUSIONS: Secreting and non-secreting adrenal lesions were treated safely by laparoscopy. Relatively small incidentalomas and subclinical hormonally active tumours can be removed by laparoscopy. Early diagnosis enhances prevention and treatment.  相似文献   

16.
BACKGROUND: The incidental discovery of an adrenal mass poses the problem of distinguishing between the frequent benign masses and the infrequent malignant ones that require surgery. Univocal guidelines to approach this problem are unavailable. OBJECTIVE: To perform a survey of the clinical management of incidentally discovered adrenal masses (ie, adrenal incidentalomas). DESIGN: A multicentric retrospective analysis of hospital medical records of adrenal incidentalomas diagnosed during a 5-year period; the medical records were scrutinized for demographic data and clinical details by means of a specifically tailored questionnaire. SETTING: The major surgical and medical centers of Piedmont, a northern Italian region with approximately 4 million inhabitants. The recruitment pattern of these centers was unselected. PATIENTS: The definition of adrenal incidentaloma was limited to patients with a physical examination and a clinical history unindicative of adrenal disease. Exclusion criteria also included hypertension of suspected endocrine origin and a history of neoplasms known to metastasize frequently in the adrenal glands. Two hundred twenty-four medical records were collected, and 210 were analyzed (14 excluded a posteriori). RESULTS: Most patients were in their 50s and 60s, and women were predominantly affected. The frequency of adrenocortical cancer was 13% among patients operated on. The tumor diameter was highly correlated with the risk of cancer; a cutoff at 5 cm had a sensitivity of 93% with a specificity of 64% in discriminating between benign and malignant cortical lesions. CONCLUSIONS: The occurrence of adrenocortical carcinoma among adrenal incidentalomas is not rare. The evaluation of the mass size is a simple and effective method for selecting patients at risk for cancer. The indication for surgery of masses larger than 5 cm, or of masses of any diameter that have suspicious imaging characteristics, limits unnecessary operations and costs.  相似文献   

17.
Hemorrhagic adrenal metastasis from lung cancer is extremely rare, although adrenal involvement is common in widely disseminated cancer. We report a case of massive adrenal hemorrhage secondary to metastasis of lung cancer. A 47-year-old female was treated by left upper lobectomy and mediastinal lymph node resection for an adenocarcinoma with intrapulmonary metastasis in the left upper lobe. Eight months later, she presented with right flank and back pain, and abdominal ultrasonography and computed tomography showed a right solitary adrenal tumor with massive hemorrhage. The tumor was not resectable and partially responded to chemotherapy. A massive adrenal hemorrhage, secondary to metastasis of lung cancer, presents with nonspecific clinical signs and symptoms. In lung cancer patients with an acute flank or back pain, hemorrhagic adrenal metastasis should be considered in the differential diagnosis.  相似文献   

18.
INTRODUCTION: Magnetic Resonance Imaging (MRI) has been proposed as the diagnostic technique of choice to characterize adrenal tumors. However, the results of the current studies are controversial. MATERIAL AND METHODS: Forty-nine patients with unilateral adrenal masses were submitted to MRI for lesion characterization on the basis of MR signal intensity. Cytology and/or histology demonstrated 14 pheochromocytomas (pheos), 11 adenomas, 3 cysts, 2 myelolipomas, 4 carcinomas, 3 metastases and 1 fibrosarcoma; a clinical diagnosis of adenoma was made in the remaining 11 patients. MR studies were performed using spin-echo (SE) sequences with T1 (TR/TE = 600/17 ms) and T2 (TR/TE = 2000/15-90 ms) weighting. T1-weighted images were also acquired after Gadolinium-DTPA (Gd-DTPA) administration. MR studies were integrated with in- and out-of-phase (TR/TE = 100/4-6 ms) chemical-shift (CS) sequences. MR signal intensity (SI) was analyzed qualitatively and quantitatively; MR results were correlated with tumor type and hormone secretion. RESULTS: The qualitative analysis of T2 images showed high signal intensity in the majority (80%) of adrenal lesions (14 pheos, 12 adenomas, 3 cysts, 2 myelolipomas and 8 malignancies). The quantitative analysis of post-Gd-DTPA T1 images permitted to distinguish adenomas, cysts and myelolipomas from pheos and malignancies. The qualitative analysis of post-Gd-DTPA T2 and T1 images permitted to distinguish pheos and cysts from adenomas and malignancies (p < .05); however, pheos and cysts as well as adenomas and malignancies were not differentiated. MR SI was similar in secreting and nonsecreting adenomas from both a qualitative and a quantitative viewpoints. CS MRI permitted to distinguish adenomas (decreased signal intensity on out-phase relative to in-phase images) from other benign and malignant lesions (no signal change from out-phase to in-phase images). CONCLUSIONS: The qualitative analysis of MR SI on conventional T1 and T2 images does not permit to differentiate adrenal masses. The qualitative evaluation of T1 images after Gd-DTPA administration, the quantitative analysis and CS sequences are technical options improving lesion characterization.  相似文献   

19.
STUDY DESIGN: Tantalum- and titanium-based lumbar interbody fusion devices were implanted into two fresh human cadavers, and magnetic resonance and computed tomographic imaging were performed to evaluate adjacent spinal structures and the amount of metallic artifact. OBJECTIVE: The objective of this study was to prospectively compare the preliminary results of magnetic resonance imaging and computed tomography scanning image quality after the implantation of both titanium and tantalum spinal implants. SUMMARY OF BACKGROUND DATA: The availability of tantalum and titanium spinal implants brings theoretical magnetic resonance imaging compatibility along with several other desirable characteristics. The magnetic resonance imaging and computed tomographic imaging of tantalum spinal instrumentation has never been studied previously or compared with titanium instrumentation. METHODS: Titanium and tantalum spinal implants produced for anterior spinal fusion were each placed at two levels in the lumbar spine of two fresh cadaver specimens. Sequential spin echo T1-weighted and T2-weighted magnetic resonance imaging studies and computed tomographic scans were obtained. The resulting images were then graded to describe and compare the behavior of tantalum metal in magnetic resonance imaging and computed tomographic studies. RESULTS: Good T1 and T2 images were obtained that allowed visualization of the neural structures with minimal artifact. The optimal T1 images for tantalum metal were similar in quality to the optimal T1 parameters for titanium metal. T2 images for both tantalum and titanium metal were obtained with similar results for both metals. Gradient echo magnetic resonance imaging scans of both were poorly imaged with a large amount of artifact. Computed tomographic studies of tantalum implants produced a large amount of metal artifact when compared with computed tomographic studies of titanium implants. CONCLUSIONS: High-quality magnetic resonance imaging studies can be obtained after the implantation of both titanium and tantalum spinal instrumentation. Both of the metals produce similar images on magnetic resonance imaging studies with comparable amounts of metallic artifact. High-quality computed tomographic scans of titanium implants can be obtained with minimal distortion secondary to artifact. However, computed tomographic scanning is not the imaging modality of choice for the tantalum spinal implants because of the large amounts of artifact.  相似文献   

20.
PURPOSE: To determine the usefulness of transthoracic needle biopsy of mediastinal lymphadenopathy for staging suspected lung and other cancers. MATERIALS AND METHODS: Transthoracic needle biopsy of the hilum or mediastinum was performed in 111 patients with suspected neoplasms. Most biopsy procedures were performed with computed tomographic guidance on an outpatient basis. Forty-eight adult patients had enlarged lymph nodes (defined as < or = 30 mm in the long axis and > or = 10 mm in the short axis). Sixty-three lesions larger than 30 mm were arbitrarily considered to be masses and were excluded. RESULTS: Carcinoma was diagnosed in 40 patients. Four patients had true-negative and one patient had false-negative results. Sensitivity for carcinoma was therefore 98% (40 of 41). One patient with a negative biopsy result did not have surgical confirmation and was excluded from analysis. Lymphoma was excluded from analysis. Lymphoma was diagnosed in two patients (positive in one and suspicious in one). Pneumothorax occurred in 19 (34%) of 56 biopsy procedures. Chest tube treatment was required in eight (14%). CONCLUSION: Transthoracic needle biopsy of mediastinal lymphadenopathy is a safe, accurate diagnostic staging procedure. It can frequently be used as an alternative to mediastinoscopy in patients with lymphadenopathy.  相似文献   

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