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Objective: The objective of this study was to assess the prevalence of pathologically proven intrapulmonary lymph nodes and to evaluate their appearance on CT., Materials and Methods: Over a 15-year period (1980-1994), 184 patients underwent minithoracotomies for evaluation of CT-detected peripheral pulmonary abnormalities. Of these 184 patients, 96 had well-circumscribed peripheral pulmonary nodules. The size, position, and radiographic features of all pathologically proven intrapulmonary lymph nodes were independently assessed by two experienced radiologists., Results: The nodules in 17 (18%) of the 96 patients with well-circumscribed peripheral pulmonary nodules were pathologically proven to be intrapulmonary lymph nodes. Two of the 17 patients had two nodules; the remaining patients had solitary nodules. The maximum diameter of the nodules varied from 7 to 12 mm. All the nodes were located within 20 mm of a visceral pleural surface. Twelve of the nodules were located in the lower lobes, and the remaining nodules were located in the right middle lobe., Conclusion: Although intrapulmonary lymph nodes are not a well-known entity, our results indicate that they are discovered in a significant number of patients who undergo minithoracotomies for the evaluation of CT-detected pulmonary nodules. Although these lymph nodes do not possess any specific CT appearance, they should be considered in the differential diagnosis of single (or multiple) parenchymal nodules, particularly those found in the lower lobes.

Over the past 13 years 681 consecutive patients have undergone computed tomographic staging and surgical staging of the mediastinum. Five hundred one tested negative for mediastinal lymph node enlargement by computed tomographic staging, and 37 of these patients had cancerous mediastinal lymph nodes at thoracotomy (n = 36) or mediastinoscopy (n = 1). The survival in this group of patients was analyzed according to T status, central or peripheral location of tumor, cell type, areas of mediastinum that are involved, and extent of nodal involvement with tumor. Twelve patients had central tumors, and 25 had peripheral tumors. Two of the patients in the central tumor group died postoperatively and only 2 others survived, whereas 12 of the 25 patients in the peripheral tumor group survived. Four of the 37 patients, 2 in each group, did not undergo resection, and all died. All but 2 of the 31 survivors who underwent resection received postoperative adjuvant x-ray therapy (23 patients), chemotherapy (1 patient), or x-ray therapy and chemotherapy (5 patients). The projected 2-year and 5-year survivals (Kaplan-Meier) were 40% and 28% for patients overall, 46% and 31% for those whose tumors were resected, 40% and 20% for those with resected central tumors, and 52% and 45% for those with resected peripheral tumors. None of these differences was significant. Cell type, location or number of locations of involved nodes, and the average percentage or maximum percentage of mediastinal node that was involved with tumor did not influence survival. The high negative predictive index for computed tomographic staging of the mediastinal lymph nodes and the observed 2-year and 5-year survivals in patients with false-negative computed tomographic scans of the chest justifies definitive thoracotomy without mediastinoscopy in most patients with a normal mediastinum on computed tomographic scan.

Twenty-five patients had Russe anterior corticocancellous bone-grafting between 1973 and 1984 for twenty-six symptomatic established non-unions of the scaphoid. The mean duration of follow-up was eleven years (range, seven to eighteen years). Twenty-one (81 per cent) of the twenty-six scaphoid bones united. We developed two rating scales to evaluate the results of the operation. One scale, based on objective findings, included the radiographic appearance of the wrist, the range of motion, and strength; the other scale, based on subjective findings, comprised function, pain, perception of a decrease in performance because of limitation of motion or strength, and satisfaction. These scales were used to compare the objective and subjective results in patients who had a malunion of the scaphoid in which the lateral intrascaphoid angle was more than 45 degrees convex dorsally between the proximal and distal poles (a so-called flexion or humpback deformity, which results in extension of the proximal fragment of the scaphoid at the radiocarpal joint) with the results in patients who had no such deformity. The lateral intrascaphoid angle was more than 45 degrees in thirteen (50 per cent) of the twenty-six wrists. Although the difference in the objective results between the wrists that had a malunion and those that did not have a malunion was highly significant (p = 0.001), there was no significant difference in the subjective results between the two groups, including satisfaction of the patient (p = 0.39). Twenty-three patients (92 per cent) returned to full-time employment and twenty-two (88 per cent), to sports activities. Twenty-three patients (92 per cent) reported that they had pronounced relief of pain and that the procedure had improved their quality of life. The presence of this deformity of the scaphoid after bone-grafting for a symptomatic non-union was not predictive of a poor long-term subjective outcome.

We retrospectively reviewed abdominal computed tomographic (CT) studies from 20 patients with sclerosing cholangitis and found evidence of abdominal lymphadenopathy in 13 patients. Enlargement occurred primarily in areas draining the liver, such as the gastrohepatic ligament or celiac axis (N = 8), the porta hepatis (N = 7), and the pancreaticoduodenal region (N = 2). One patient had reactive adenopathy and retroperitoneal fibrosis. The presence of benign reactive lymphadenopathy in at least one intraabdominal location was confirmed by pathological examination of excised lymph nodes in seven patients. Malignancy was excluded by surgical exploration or clinical follow-up. We conclude that enlarged lymph nodes are a common finding by CT in patients with sclerosing cholangitis. Enlarged reactive lymph nodes in this condition should not be mistaken for evidence of periportal metastasis or cholangiocarcinoma.

Small peripheral pulmonary nodules ranging in size from 1 mm to 20 mm were excised in 58 patients. Computed tomography was used to mark the skin overlying the nodules to minimize the surgical exposure needed for operative identification. The nodules were 1 cm or less in maximum diameter in 76% of the patients. Twenty-six patients had single nodules and 32 patients had multiple nodules. The preoperative diagnosis was inaccurate in 67% of the patients. In 61% of the patients in whom malignancy was suspected, no tumor was demonstrated. Conversely, of the 20 patients in whom a malignant nodule was excised, the preoperative diagnosis was correct in only 50%. Thirty-one patients required no further treatment apart from their biopsy and 27 required additional intervention. Small peripheral pulmonary nodules require biopsy for diagnosis. When percutaneous needle aspiration biopsy is unsuccessful, or technically difficult, a computed tomography-guided thoracotomy is an effective and minimally invasive surgical alternative.

Exclusive reliance on radiographic techniques for the diagnosis of renal angiomyolipoma can lead to misdiagnosis when the histological status is atypical, computerized tomographic findings are equivocal or renal cell carcinoma coexists. We report our experience and those of others in combining fine needle aspiration biopsy and radiological imaging to identify renal angiomyolipoma. Fine needle aspiration biopsy is safe and provides accurate histological diagnosis of renal angiomyolipoma.

The relative value of magnetic resonance imaging (MRI) versus computed tomography (CT) for imaging benign and malignant lesions of the maxilla and mandible was studied in a group of 16 patients. The imaging methods were evaluated for their ability to detect the lesion and define lesion margins, soft tissue extension, and bone involvement. The abnormality was identifiable with both imaging methods. For benign cystic lesions of either the maxilla or mandible (50%), MRI was overall equal to or better than CT. Magnetic resonance imaging was superior to CT in the evaluation of lesion margins and soft tissue extent of disease, whereas it was equal or slightly inferior to CT in lesion detection and in the evaluation of bone involvement. In the imaging of malignant neoplasms (50%), MRI was overall superior to CT in all four categories reviewed. Magnetic resonance imaging also had the highest rate of correlation with clinical findings, either from physical examination or at the time of surgery.

An isolated anterior echo-free space is generally regarded as a false-positive echocardiographic finding for pericardial effusion. Even when an anterior echo-free space is accompanied by a posterior echo-free space, the echo-free spaces have been occasionally reported to be falsely positive for pericardial effusion, principally in patients with cardiac neoplasms. The basis for these findings had never been adequately explained. In the present study, evaluation by computed tomographic imaging or necropsy examination of 5 patients in whom there was either an anterior or posterior echo-free space or both demonstrated that subepicardial adipose tissue is the echocardiographic imitator of pericardial effusion.

A case of global renal infarction resulting from blunt renal trauma is presented. The cortical 'rim sign' on computed tomographic (CT) scanning is suggestive of major renal arterial occlusion. Clinicians who use CT scanning as the initial imaging modality for the evaluation of blunt kidney trauma should be aware of this sign and its implications for management.

The limitations of routine radiography of the feet in demonstrating tarsal coalitions are well known. Even with the use of multiple projections of the foot, tarsal coalitions may escape detection. Computed tomographic examinations of the feet were performed in persons suspected of having tarsal coalitions. The CT images were obtained in both the longitudinal and axial axes of the foot. Results of these examinations suggest the longitudinal projection to be most helpful in demonstrating talonavicular coalitions and the axial projection in demonstrating talocalcaneal coalitions. The history, pathology, and other imaging modalities of tarsal coalitions are reviewed.

To more clearly characterize the role of computed tomography in staging the mediastinal lymph nodes of patients with lung cancer, we analyzed computed tomographic and surgical findings in the chest in 345 consecutive patients with lung cancer who underwent operative staging. Patients were grouped according to the TNM staging system of the American Joint Commission, central or peripheral location of the primary tumor, lobar location of the tumor, and maximum tumor diameter as determined by computed tomography or gross pathology. One third of patients with abnormal findings on the computed tomographic scan did not have mediastinal lymph node metastases. Mediastinal metastases occurred frequently in patients with central cancers (38%). The predictive value of a negative scan in all patients was high (greater than or equal to 90%) except for patients with central T3 lesions (72%), left upper lobe lesions (83%), and central adenocarcinomas (75%). However, only the differences between central T3 and central T2 or T1 lesions, and between central adenocarcinomas and central squamous cell carcinomas, were unlikely to be due to chance alone (p less than 0.05). None of the lobar differences were statistically significant. The frequency of mediastinal metastases in patients with peripheral lesions was 15% (28 of 192 patients); computed tomography correctly identified enlarged mediastinal lymph nodes in all but seven patients. However, there were no true-positive computed tomographic scans in 59 patients with peripheral lesions 2 cm in diameter or smaller; accordingly, we suggest that computed tomography is not indicated for the sole purpose of mediastinal staging in this group. Ninety-four percent of patients in this series undergoing thoracotomy with a curative intent had a curative resection. Only 4% had unresectable lesions; palliative resections were done in 2%.

Correlative imaging by dual-isotope thallium/technetium subtraction scintigraphy, computed tomography, and magnetic resonance imaging demonstrated a pathologically proven parathyroid adenoma in a 62-year-old man with known neurofibromatosis, who presented with hypercalcemia and an elevated parathormone level. The association between neurofibromatosis and primary hyperparathyroidism is discussed.

Routine comparison views in cases of suspected extremity injury in children have not been adequately substantiated, in the authors' opinion. Three hundred such cases were reviewed, with pediatric radiologists requesting comparison views of the uninjured side in 8%. In no case did the comparison view change the initial diagnosis. When the initial interpretation is made by pediatric radiologists, selective use of comparison views is more cost-efficient and delivers less radiation to patients and personnel, compared to obtaining them routinely in all cases.

Computed tomography of the liver in hemochromatosis characteristically demonstrates diffusely increased attenuation. We report a patient with this disorder who presented with such a finding over the right lobe of the liver and a benign, large lower density area occupying the other lobe, closely simulating malignancy. Biopsies of the liver showed prominent fibrosis of the left lobe as compared with the right lobe, which probably accounts for the attenuation difference.

Two examples of gas collections within the spinal canal, noted on computed tomography, are presented. A probable etiology is suggested and possible misinterpretations of such a finding are discussed.

The CT appearance of bronchogenic cysts is well known. In addition, CT is useful in evaluating cases of suspected superior vena cava (SVC) syndrome. Although most cases of SVC syndrome are caused by malignant diseases, certain benign disorders such as granulomatous infections may be the underlying cause. A case of a bronchogenic cyst causing SVC occlusion is presented here.

A review of 23 consecutive patients with tumors of the nasopharynx and maxillary sinus seen over a two-year period was carried out. The purpose was to assess the value of computerized tomography (CT) in the definition of tumor extension to contiguous structures and its effect on treatment selection and management.CT was found to be very useful in detailing bone and soft-tissue invasion. In 11 of 15 patients with nasopharyngeal cancer and in the eight patients with maxillary sinus tumors, the selection of treatment and the techniques of irradiation were influenced by the CT findings.There is a high degree of accuracy in the evaluation to the nasopharynx and maxillary sinus by CT. This improvement in pretreatment assessment of the tumors enables adequate treatment to be offered. Since most of the failures of treatment are a result of local recurrence, improvement in local control is likely to result in improved survival.

Two cases are presented which demonstrate the utility of CT scanning in the evaluation of patients with septic sacroiliitis. The importance of making an early diagnosis in such patients is noted and the roles of various other modalities are related to that of CT scanning.

Necrotising enterocolitis may occur as a complication of granulocytopenia of any aetiology. The clinical presentation may be non-specific and the diagnosis therefore depends heavily on radiographic findings, particularly changes seen by CT. In immune-compromised patients being investigated for possible abdominal sources of fever, CT may be particularly helpful in elucidating bowel sources of infection. Two cases of necrotising enterocolitis demonstrated by CT are presented. The two cases were in immune-compromised patients with malignant disorders who presented with fever. The CT findings of this disorder are presented.

The authors retrospectively evaluated computed tomographic (CT) scans obtained in 21 patients with primary biliary cirrhosis, 13 of whom subsequently underwent liver transplantation. Evidence of enlarged lymph nodes, primarily in the gastrohepatic ligament and porta hepatis, was seen on CT scans in 17 patients (81%). Lymphadenopathy also occurred in unusual sites for benign adenopathy, including the paracardiac (24%) and mesenteric (19%) lymph nodes. Surgical or autopsy confirmation of enlarged lymph nodes was made in 13 patients, and histologic analysis of the specimens revealed reactive hyperplasia, sinus hyperplasia, sinus histiocytosis, fibrosis, or normal architecture in these enlarged nodes. The authors conclude that lymphadenopathy is a frequent CT finding in primary biliary cirrhosis and that recognition can help prevent misdiagnosis of lymphoma or metastatic disease.

To evaluate the use of computed tomography (CT) in the diagnosis of pericardial heart disease, 53 patients were prospectively studied by computed tomography of the chest and cardiac ultrasound. A diagnostic-quality CT study was done for all patients; a technically satisfactory ultrasound examination was not possible in six patients. Of 47 patients in whom both chest scans and satisfactory ultrasound studies were obtained, computed tomography showed pericardial thickening not shown by ultrasound in five patients. Estimated size of pericardial effusion was the same for both computed tomography and ultrasound. Computed tomography provided quantifiable evaluation of the composition of pericardial fluid in seven patients with either hemopericardium or purulent pericarditis. Neoplastic pericardial heart disease was detected by CT scan in four of the 53 patients. Computed tomography of the chest provides a sensitive evaluation of the pericardium and quality of pericardial effusion, and is a valuable adjunct in patients in whom cardiac ultrasound is technically unsatisfactory.

The clinical management of renal calculi would be aided if a direct in vivo determination of stone chemical composition could be made. We investigated the possibility of obtaining this information by a quantitative analysis of the computerized tomography scan images of 80 urinary calculi. Our results show that by using an appropriately calibrated computerized tomography scanner the differentiation of stone chemical composition can be made on the basis of 3 parameters, namely, absolute computerized tomography value at a single x-ray energy, the difference between computerized tomography values measured at 2 different x-ray energies, and computerized tomography value-frequency histograms (pixel patterns) of the stones. Uric acid stones were differentiated from all other stones at a significance level of p less than 0.001. Cystine was differentiated from calcium oxalate and brushite at the same significance level. Using pixel patterns cystine and struvite were separated from each other correctly with 70 per cent accuracy. Struvite stones of low or moderate calcium phosphate content were identified correctly with 80 per cent accuracy. Struvite stones of high calcium phosphate content could not be differentiated from calcium oxalate or brushite. Calcium oxalate and brushite could not be separated. The minimum stone size that allowed chemical identification was established for each stone type. In addition, we demonstrated that all the urinary calculi examined were visible on computerized tomography scan regardless of chemical composition or size.

Clinically significant adrenal hemorrhage due to adrenal metastases has rarely been reported. We describe three cases of this unusual entity, two from lung carcinoma and one from sarcoma. Adrenal hemorrhage was bilateral in two patients, and was the presenting manifestation of malignancy in two. A computed tomography diagnosis of hemorrhage within bilateral adrenal metastases was made when adrenal masses rapidly enlarged in one case, and when previously resolving hematomas showed enlargement in a second case. The third case was believed to represent a pheochromocytoma preoperatively. We conclude that significant adrenal hemorrhage can result from adrenal metastases and can be the presenting manifestation of metastatic tumor. In the patient without discernible risk factors for adrenal hemorrhage, underlying malignancy should be considered as a possible cause, even if the hemorrhage is bilateral.

Two cases of computed tomographic demonstration of gas collections simulating gas forming organism infection are presented in patients shown subsequently not to be infected--the air resulting from tissue necrosis. These observations are helpful in guiding conservative management of certain patients in the appropriate clinical setting.

Computed tomography (CT) is now used extensively for the evaluation of orbital, facial, and intracranial infections. Nine patients are presented to illustrate the importance of detecting underlying and unsuspected sinusitis. Prompt treatment of the sinusitis is essential to minimize the morbidity and mortality associated with complications such as brain abscess, meningitis, orbital cellulitis, and osteomyelitis. A review of the literature documents the persistence of these complications despite the widespread use of antibiotic therapy. Recognition of the underlying sinusitis is now possible with CT if the region of the sinuses is included and bone-window settings are used during the examination of patients with orbital and intracranial infection.

The location and relative size of echo-free spaces observed by cardiac ultrasound have been considered reliable signs for distinguishing pericardial fat from fluid; spaces that are exclusively anterior have been considered to represent fat, while spaces that are exclusively or predominantly posterior have been considered to represent fluid. In the present study, the location and relative size of echo-free spaces in eight patients suggested the diagnosis of pericardial effusion; evaluation by computed tomography or thoracotomy, or both, in six and necropsy in two, however, disclosed that these echo-free spaces--posterior as well as anterior--were exclusively due to fat. Age appeared to be as important a predisposing factor as obesity in the accumulation of excess subepicardial fat. No M-mode or two-dimensional features were found to be reliable in differentiating fat from fluid, although excessive amplitude of the posterior pericardial echo on the M-mode study favored the diagnosis of fat. Thus, the finding of echo-free spaces by cardiac ultrasound, even when the posterior space is isolated or larger than an accompanying anterior space, is not necessarily indicative of pericardial fluid. In elderly patients, in particular, posterior echo-free spaces due to fat may invite an incorrect diagnosis of pericardial effusion or pericarditis. In patients in whom echo-free spaces represent an unexpected finding of cardiac ultrasound examination, computed tomography of the chest may be helpful in establishing whether they are due to fat or fluid.

Computed tomography (CT) is a sensitive, noninvasive radiographic technique which can produce detailed cross-sectional images of any anatomic region. The amount and accuracy of the information it provides far exceeds that produced by conventional radiographic techniques. The chemosurgeon can find CT scanning invaluable in his preoperative evaluation of patients with large, invasive head and neck tumors of cutaneous origin.

Acute renal infarction and acute pyelonephritis can have identical clinical presentations. Most of the computed tomography findings seen in acute renal infarction are similar to those in acute pyelonephritis, except for the characteristic cortical rim sign seen in acute infarction. This finding differentiates these two disorders. This sign may be subtle and not appreciated unless searched for diligently with appropriate computed tomography imaging at varying window settings with particular attention to the subcapsular region.

Complete or partial absence of the pericardium is a relatively rare disorder. While physical examination, electrocardiogram, and chest x-ray may suggest the diagnosis, definitive noninvasive diagnosis has until recently not been possible. In the patient described in the present report, the basis for chest pain initially attributed to myocardial ischemia was established noninvasively by computed tomographic examination of the chest to be congenital absence of the left pericardium. Experience with this patient emphasizes the fact that one of the known bases for nonischemic chest pain--congenital pericardial defects--can be precisely defined by contrast-negative computed tomographic imaging.

A modified coaxial technique for the biopsy of small or deeply situated lesions using computed tomographic (CT) guidance is described. A 22-gauge needle was passed coaxially through an outer 18-gauge introducing needle and aspiration biopsy was performed. This modified coaxial technique allows for multiple biopsies to be obtained safely, expeditiously, and repeatedly.