Biomedical subjects

L E Quint

Publications and source records attributed to L E Quint.

67 records · Page 4Linked to original sources

PubMed1987

MR imaging of hepatic focal nodular hyperplasia: characterization and distinction from primary malignant hepatic tumors.

Spin-echo MR imaging at 0.35 T was used to image hepatic focal nodular hyperplasia (FNH) and to attempt to distinguish it from primary malignant hepatic tumors. There were six FNH and 10 malignant tumors including seven hepatocellular carcinomas, two cholangiocarcinomas, and one hepatoblastoma. Our results show that FNH has a fairly consistent appearance, dissimilar from that of malignant primary hepatic tumors. Four of six FNH lesions were isointense (except for a central scar in three) and indistinguishable from normal hepatic parenchyma on all pulse sequences, whereas two of six were homogeneous but slightly hyperintense on T2-weighted sequences. Furthermore, a central hyperintense scar was seen in three of six lesions on T2-weighted sequences. In contrast, each of the malignant primary hepatic tumors was hyperintense on T2-weighted sequences and seven of 10 were hypointense on T1-weighted sequences; in nine of 10, heterogeneous areas of intensity were noted. In two fibrolamellar hepatocellular carcinomas a central scar was seen that was hypointense on all pulse sequences. By using quantitative data, the best characterization was obtained by using lesion/normal-liver intensity ratios from a T2-weighted sequence; all FNH had a ratio less than 1.33, while in nine of 10 primary malignant tumors it was greater than 1.41. We conclude that focal nodular hyperplasia may have a consistent appearance on spin-echo MR imaging and probably can be distinguished from primary malignant lesions in most instances.

Adenoma, Bile Duct↗

PubMed1987

CT evaluation of mediastinal lymph nodes in lung cancer: influence of the lobar site of the primary neoplasm.

Previous reports have shown differences in the ability of CT to detect mediastinal lymph nodes, depending on the precise mediastinal location of the nodes. Poorest correlation between findings on CT and findings at autopsy has been described for left-sided lymph nodes, particularly those in the left peribronchial region (American Thoracic Society node station 10L), suggesting that cancers of the left lung might be less well staged by CT than cancers of the right lung. The relationship between the accuracy of mediastinal lymph node staging and the location of the primary lung cancer was examined in a retrospective study. In 103 patients with non-small-cell bronchogenic carcinoma who had preoperative CT evaluation of the mediastinum, the accuracy of preoperative staging was 81% for tumors of the right lung (70 patients) and 97% for tumors of the left lung (33 patients). The conclusion is that cancers of the left lung are staged at least as accurately as cancers of the right lung, despite the fact that left-sided mediastinal nodes are depicted more poorly on CT. Subcarinal and crossover (contralateral) nodal metastases and a low prevalence of metastasis involving only region 10L were the most important factors minimizing staging differences based on the site of the primary tumor.

Humans↗

PubMed1986

Mediastinal lymph node detection and sizing at CT and autopsy.

Although CT has assumed a major role in the preoperative evaluation of the mediastinum in patients with lung carcinoma, there is no consensus as to its accuracy or efficacy in this setting. A potential source of CT error is inaccurate detection or sizing of lymph nodes in particular mediastinal locations because of inadequate contrast with surrounding tissue or partial volume effects. We imaged five cadavers with CT and then meticulously dissected the mediastinal nodes. The nodes were measured and categorized by using the lymph node mapping scheme of the American Thoracic Society. The short axis nodal diameter was the best CT predictor of nodal volume. Excellent correlation was found between CT and autopsy for lymph node detection in right-sided mediastinal lymph nodes; poorer CT/autopsy correlation was found for left-sided lymph nodes, especially in the lower left peribronchial region. These findings suggest that CT may be less accurate in identifying left-sided mediastinal metastases.

Adult↗

PubMed1985

Esophageal carcinoma: CT findings.

Preoperative CT scans of 33 patients with esophageal cancer were reviewed to assess staging accuracy and define the role of CT in patients being considered for transhiatal blunt esophagectomy. Surgical and pathological verification was obtained in all cases. Only 13 tumors were staged correctly according to the TNM classification. In addition, CT was not useful in assessing resectability because of its low accuracy in evaluating aortic invasion and the fact that few patients had tracheobronchial or aortic invasion or hepatic metastases at presentation.

Adenocarcinoma↗

PubMed1985

Esophageal imaging by MR and CT: study of normal anatomy and neoplasms.

In 20 patients with normal esophagi, spin-echo magnetic resonance (MR) imaging was performed to determine the appearance at different pulse sequences and T1 and T2 values. Twelve patients with esophageal carcinoma were also studied by both MR and computed tomography (CT); in ten, there was correlation with surgical and pathologic findings. Both MR and CT showed low accuracy in staging the tumors (40% and 70%, respectively), mainly because of difficulty in detecting tumor invasion through the muscle layer into periesophageal fat. Relatively T1-weighted images (repetition time, 0.5 second; echo time, 28 msec) were best for depiction of both normal esophageal anatomy and esophageal tumors. T1 and T2 measurements varied widely for both normal and abnormal esophagi and thus were not useful in predicting histologic findings.

Carcinoma↗

PubMed1985

Normal mediastinal lymph nodes: number and size according to American Thoracic Society mapping.

CT was used to investigate the number and size of normal mediastinal lymph nodes at 11 intrathoracic nodal stations defined by the American Thoracic Society lymph-node mapping scheme. Nodal size was measured both as short- and long-axis diameters in the transverse plane. Findings for 56 patients show the largest normal mediastinal nodes to be in the subcarinal and right tracheobronchial regions. Upper paratracheal nodes were smaller than lower paratracheal or tracheobronchial nodes, and right-sided tracheobronchial nodes were larger than left-sided ones. From the distributions of node sizes, thresholds were set above which nodes in any region might be considered enlarged. These thresholds, in agreement with a prior investigation of patients with lung cancer, suggest 1.0 cm as the upper limit of normal for the short axis of a mediastinal node in the transverse plane.

Adult↗

PubMed1985

Imaging of the pulmonary hilum: a prospective comparative study in patients with lung cancer.

Using magnetic resonance imaging (MRI), dynamic computed tomography (CT), and 55 degrees posterior oblique tomography, the authors prospectively evaluated the pulmonary hilum in 35 patients with lung cancer; 19 of these patients had surgical excision of ipsilateral hilar lymph nodes and formed the study group. Their results showed no significant differences between the three imaging methods in overall accuracy of hilar evaluation. Both MRI and dynamic CT were highly sensitive but relatively nonspecific for diagnosing hilar metastasis, whereas oblique tomography had fair sensitivity and specificity. The low specificity of MRI and dynamic CT was due to detection of mildly enlarged (10-16 mm) benign hilar nodes, which were present in five (26%) of 19 patients. The calculated magnetic relaxation times, T1 and T2, were not useful in distinguishing between benign and malignant enlarged hilar nodes. The authors conclude that accurate staging of the pulmonary hilum in patients with lung cancer is not currently possible using MRI, CT, or oblique tomography.

Adenocarcinoma↗

PubMed1985

Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms.

This study identified risk factors associated with rupture of small abdominal aortic aneurysms in patients initially selected for nonoperative management. Sixty-seven patients, 53 men and 14 women, 50 to 91 years of age (mean 72 years) were followed 3 to 99 months (mean 36 months). All patients underwent serial aortic ultrasonography. The annual rate of aneurysm rupture was 6%, with an annual mortality rate caused by rupture of 5% and an annual mortality rate caused by coexistent disease of 6%. Thirty potential risk factors, including blood pressure, aneurysm size measured by ultrasonography, rate of aneurysm expansion, smoking, serum cholesterol levels, and cardiac, pulmonary, and renal risks, were analyzed by Cox proportional hazards regression to identify variables related to rupture. Aneurysm anteroposterior expansion rates varied from 0 to 1.5 cm/year but were not different in aneurysms that ruptured. Only diastolic blood pressure, initial aneurysm anteroposterior diameter, and degree of obstructive pulmonary disease were independently predictive of rupture (p less than 0.05, Wald test). With these data, actuarial rupture rates were predicted for patients with selected values of these three covariates. Predicted 5-year rupture rates varied from 2% when these risk factors were absent to 100% when all three risk factors were significant. Obstructive pulmonary disease, initial aneurysm size, and diastolic hypertension must be evaluated prospectively to assess their accuracy in predicting small aneurysm rupture.

Actuarial Analysis↗

PubMed1984

CT evaluation of chondroblastoma.

Chondroblastoma is a rare benign primary bone tumor with generally characteristic plain radiographic features. In some cases, however, the benign nature and the extent of the lesion may not be appreciated using conventional radiography. We report the CT findings of chondroblastoma in three patients. In one patient CT clearly defined cortical destruction, which was not well visualized on plain radiography or conventional tomography. In a second patient CT showed a sclerotic rim absent on plain radiography; this suggested the benign nature of the lesion. Other advantages and potential pitfalls of CT in evaluating chondroblastoma are discussed.

Adult↗

PubMed1984

CT evaluation of the bile ducts in patients with fatty liver.

Computed tomographic (CT) evaluation of the bile ducts in the fatty liver can be difficult, since hepatic attenuation decreases with increased triglyceride content, and liver parenchyma may become isodense with bile. Forty-seven patients with fatty infiltration of the liver were retrospectively identified. In 7 of these patients, attenuation of liver and bile differed by less than 10 HU. In 2 patients, dilated intrahepatic ducts were invisible using CT, because bile was isodense with fatty liver parenchyma. Thus, the fatty liver presents a potential pitfall in CT evaluation of the bile ducts. Obstructive jaundice can be diagnosed in patients with fatty liver, if the extrahepatic ducts and peribiliary vascular plexus region are carefully scrutinized. For maximal accuracy, scans should be obtained both before and after administration of intravenous urographic contrast material.

Bile Duct Diseases↗

PubMed1984

The mediastinum in non-small cell lung cancer: CT-surgical correlation.

Computed tomography was used to evaluate the mediastinum preoperatively in 60 patients with non-small cell lung cancer; 49 of these patients had thorough surgical-pathologic determination of mediastinal node status. Mediastinal lymph nodes were located by CT using the node-mapping scheme suggested by the American Thoracic Society and were considered abnormal when larger than 100 mm2 in cross-sectional area. The sensitivity of CT was 95% in detecting malignant mediastinal adenopathy; however, specificity was only 64%. Receiver operating characteristic (ROC) curve analysis showed that the optimal size criterion for diagnosing malignant mediastinal adenopathy is 1.0-1.5 cm when the short axis of a node is measured. CT staging of the mediastinum in patients with non-small cell lung cancer is clinically useful; negative mediastinal CT makes mediastinoscopy unnecessary, whereas positive CT should lead to biopsy of the enlarged node.

Carcinoma↗

PubMedDate not supplied

Three dimensional CT of central lung tumors.

Three-dimensional computed tomography (CT) reconstructions and conventional CT were compared with surgical/pathological findings in seven patients with central lung tumors, in order to assess accuracy in predicting the lobectomy/pneumonectomy decision. Although conventional CT surpassed 3D CT in diagnosing bronchial tumor invasion, 3D CT appeared to be better for central arterial invasion. Despite problems due to motion effects, partial volume averaging and the time consuming nature of the reconstruction process, 3D CT is probably useful in this setting and promises to have similar applications throughout the body.

Adenocarcinoma↗

PubMedDate not supplied

Pelvic CT findings after radical prostatectomy.

OBJECTIVE AND METHODS: To evaluate the spectrum of pelvic CT findings in patients who have had radical prostatectomy, we retrospectively evaluated the pelvic CT of 17 patients after surgery for prostate cancer. All patients were thought to be clinically free of local recurrence of carcinoma. RESULTS: The bladder base was retropubic in 100%, the levator sling was well delineated in its entirety in only 88%, and fat was clearly demonstrated between the rectum and bladder base in only 44%. Unsuspected findings in this group included soft tissue density structures in the resected bed of the seminal vesicles (88%) and a transversely oriented, soft tissue density bar between the bladder base and rectum (53%). A variety of symmetric abnormalities are commonly seen on postprostatectomy pelvic CT. CONCLUSION: Seminal vesical-like soft tissue structures are routinely visualized, and a horizontal bar of soft tissue in the rectovesical space is commonly demonstrated. These structures should not be confused with local tumor recurrence.

Aged↗