Vernon L. Yeager

Computed Tomography of Herniated and Extruded Nucleus Pulposus

Computed tomography (CT) is an accurate method of diagnosing herniated nucleus pulposus (HNP) in patients with hack pain and radiculopathy. We evaluated 188 patients with 244 disk space explorations for the treatment of hack pain and radiculopathy. In predicting HNP. CT was 92% accurate and myelography was 88% accurate. The only significant difference between the two modalities is at 1.5-SI. Mere CT was 92% accurate in predicting HNP and myelography was 70% accurate, a difference that is statistically significant (P 0.01). The dural sac separation reduces the myelogram accuracy at 1.5-SI. In detailed evaluation of 188 patients with both CT-diagnosed and surgically confirmed HNPs. these HNPs were classified by location, calcification. size. and extrusion. If the maximum anteroposterior diameter of the MNP was less than one-half the anticipated normal sagittal diameter of the dural sac. the incidence of extrusion was less than 10%. If it occupied one-half or more of the anticipated normal sagittal diameter of the dural sac. the incidence of extrusion was greater than 90% This difference is highly statistically significant (P 0.001). Thirty-five percent of the HNPs exhibited some degree of migration with the cephalic direction more common than the caudal direction. Computed tomography and myelography are both satisfactory methods of diagnosing HNP. The noninvasive CT gives direct anatomical information and is more accurate at 1.5-SI. If the physical examination correlates with the CT examination, then myelography may be bypassed and the patient treated with a high degree of confidence.

The Degree to Which Accuracy of Preoperative Staging of Laryngeal Carcinoma has been Enhanced by Computed Tomography

In this retrospective study, the accuracy of preoperative staging by high-resolution CT and clinical evaluation (indirect-direct laryngoscopy) is compared to the postsurgical pathologic staging of laryngeal cancer. Forty-two patients who were admitted to St. Louis University Hospital between the years of 1978 to 1985 with diagnoses of laryngeal cancer were included. All patients received high-resolution CT scan of the larynx preoperatively and subsequently underwent total or partial laryngectomy. None of these patients received preoperative radiotherapy. The accuracy of the clinical vs. CT staging—as well as the accuracy of the staging by combination of the two modalities—was determined by comparison with the postsurgical pathologic staging. The accuracy was assessed separately for glottic, supraglottic, and transglottic carcinoma. The accuracy of CT staging for glottic carcinoma was 75%. However, clinical evaluation in this group of lesions was very reliable, offering 92.9% accuracy. The accuracy of CT staging increased in the supraglottic and transglottic lesions, to become superior to the clinical staging. With combined information gained by both examinations, the preoperative staging accuracy was 91.4% for supraglottic carcinoma and 87.5% for transglottic carcinoma. It is, therefore, recommended that high-resolution CT should be included in the preoperative staging of laryngeal cancer.

An ultrastructural study of the role of calcification nodules in the mineralization of woven bone

SummaryOsteolathyrism has been used as an experimental model for the study of calcification nodules during the mineralization process. Periosteal exostoses developing in osteolathyrism characteristically have spherical basophilic structures (calcification nodules) in the vicinity of developing bone spicules. In thin sections, the nodules were seen scattered between collagen fibers in the intercellular matrix. Collagen fibers did not appear to be present within the nodules but sometimes were packed just outside them. Matrix vesicles were also present in areas of early mineralization.After EDTA decalcification, the majority of the nodules consisted of a fine granular material surrounded by an electron-dense peripheral zone. The peripheral dense zone was occasionally incomplete in small nodules in areas of early mineralization. An electron-dense central area could be observed in the center of the nodules.Evidence has been presented indicating that the calcification nodules arise from smaller mineralization foci, presumably matrix vesicles. The calcification nodules enlarge to approximately 1.0 µm in size, at which point development is slowed or halted allowing the formation of the peripheral dense zone.Although coalescence of nodules was observed, this was more a random event. The further mineralization of the trabeculae was achieved by the calcification of the collagen fibers. The mineralized trabeculae reflected this pattern of nodular and collagenous calcification. It is suggested that this pattern of calcification is characteristic of rapidly developing woven bone.

Evaluation of laryngeal cartilages by computed tomography.

Computed tomography of the laryny was performed in 21 patients and 3 anatomic specimens for evaluation of laryngeal cancer. Special attention was directed to the appearance of the laryngeal cartilages in both the normal and abnormal examinations in order to establish criteria for cancerous invasion. The problem presented by the normal nonuniformity of density of the cartilages is discussed in detail.

Ossification of the laryngeal cartilages as it relates to computed tomography.

Ossification of adult laryngeal cartilages was studied using cross sections cut in planes parallel to those used in computed tomography (CT). The percentage of ossification of surfaces of thyroid laminae was calculated and marked variations were found. There was no correlation between ossification and age (all subjects were 50 years or older). Generally, laryngeal cartilages of men were ossified to a greater extent than those of women. Some male cartilages were only slightly ossified, however, while some female cartilages were nearly completely ossified. Inner and outer surfaces of thyroid laminae differed by as much as 35% in some cases. Left and right laminae showed even greater differences, indicating that symmetry of ossification is not the rule. Ossification of arytenoid and cricoid cartilages also varies. This study reveals that there is no reliable pattern of ossification of laryngeal cartilage that would be of use the radiologist in evaluating CT scans for invasion of cartilage by cancer.

Evaluation of laryngeal cancer by computed tomography.

Six cases of laryngeal cancer have been examined by computed tomography. The findings were correlated with those obtained by laryngoscopy and in five cases by pathological examination of the surgical specimens. Computed tomography accurately delineated the extent of tumor involvement of the laryngeal and paralaryngeal soft tissues. The diagnosis of involvement of the laryngeal cartilages presents some problems, which are discussed.

Improved diagnostic accuracy in laryngeal cancer using a new classification based on computed tomography

The most commonly accepted classification of laryngeal cancer is based on the definition of regions formulated by the American Joint Committee on Laryngeal Cancer. The limitations of this classification are discussed. A new radiologic classification based on computed tomography (CT) is presented, its application illustrated, and its accuracy documented. This classification has the advantage that it provides information preoperatively which closely agrees with the pathologic facts seen postoperatively. It also helps to separate those tumors that tend to invade cartilage from those that do not. Cancer 53:44‐57, 1984.

Computed Tomography of the Larynx

Evaluation of computed tomography of the normal larynx has been performed utilizing corresponding tomographic and anatomic planes. The transaxial, coronal, and sagittal planes have been evaluated. While all three planes have distinct potential diagnostic value, the transaxial plane offers a unique view of laryngeal structures not afforded by any other technique. It is hoped that diagnostic criteria developed in this study will prove applicable to the evaluation of clinical laryngeal disease.

Improved Diagnostic Accuracy in the TNM Staging of Laryngeal Cancer Using a New Definition of Regions Based on Computed Tomography

Neither laryngoscopy nor laryngography can match the accuracy with which computed tomography (CT) can display the full tumor extent or the presence of cartilage invasion. Data obtained from a CT-histologic correlative study have suggested a new definition of regions of the larynx for use with the TNM staging of laryngeal cancer. The arytenoid cartilage, readily identifiable by CT, is used for reference. The regions are as follows: (a) supra-arytenoid, (b) midarytenoid, (c) vocal process, and (d) infra-arytenoid. Tumors with a strong propensity for cartilage invasion can be distinguished from those without this tendency. In addition, tumors with different pathways of lymphatic drainage can be identified.

Computed tomography vs laryngography: a comparison of relative diagnostic value.

The computed tomography (CT) scans and laryngograms of 25 patients with laryngeal cancer were compared and evaluated in an assessment of the diagnostic accuracy of each modality in the supraglottis glottic, and subglottic regions. Fourth generation scanners were used in these patients, all of whom subsequently underwent laryngectomy or partial laryngectomy. The clinical superiority of CT scanning was evident in several areas—confirming clinical impressions that laryngography is not as accurate as CT, is frequently misleading, and offers no significant advantages over CT. In this regard, we now believe that computed tomography is the most important radiologic adjunct in the diagnosis of laryngeal cancer, and we no longer order the laryngogram on a routine basis.