Magnetic resonance imaging of the larynx: a correlation with histologic sections

Pathologic Assessment of Computerized Tomography Accuracy for the Evaluation of the Laryngeal Cartilaginous Frame Work in Laryngopharyngeal Carcinomas

Sixty-six whole-organ sectioned laryngopharyngectomy specimens removed for cancer during a seven-year period were uniformly examined to determine the accuracy of preoperative high resolution computerized tomography (CT) for detection of cartilaginous involvement. Our results indicate that CT has a high overall specificity (88.2%) but a low sensitivity (47.1 %); we observed a high false-negative rate (26.5%) and a fairly low false-positive rate (5.9%). Massive cartilage destruction was easily assessed by CT, whereas both small macroscopic and microscopic neoplastic foci of cartilaginous invasion were missed on CT scans. Moreover, false-positive cases were mainly due to proximity of the tumor to the cartilage. Clinical implications of these results are discussed.

Staging of laryngeal cancer: endoscopy, computed tomography and magnetic resonance versus histopathology

An accurate pretherapeutic staging of laryngeal cancer is required for optimal treatment planning and for evaluation and comparison of the results of different treatment modalities. In this study, 45 consecutive patients with neoplasms of the larynx, treated surgically, were included in a prospective pretherapeutic staging protocol that included indirect laryngoscopy, direct microlaryngoscopy, contrast-enhanced computed tomography (CT) and Gd-DTPA-enhanced magnetic resonance imaging (MRI). The surgical specimens were cut in whole-organ slices parallel to the plane of the axial CT and MR images. The histologic findings were then compared with clinical findings, CT and MRI. These findings showed that clinical evaluation failed to identify tumor invasion of the laryngeal cartilages and extralaryngeal soft tissues, resulting in a low staging accuracy (55%). Many pT4 tumors were clinically understaged. The combination of clinical/endoscopic evaluation and either CT or MRI resulted in a significantly improved staging accuracy (80% vs 87%, respectively). MRI was significantly more sensitive but less specific than CT in detecting neoplastic cartilage invasion. MRI tended to overestimate neoplastic cartilage invasion to possibly result in overtreatment, while CT was found to underestimate neoplastic cartilage invasion and could lead to inadequate therapeutic decisions.

Pretherapeutic staging of laryngeal carcinoma. Clinical findings, computed tomography, and magnetic resonance imaging compared with histopathology

BACKGROUND

An accurate pretherapeutic staging of laryngeal carcinoma is required for most treatment planning as well as for evaluation and comparison of the results of different treatment modalities. Neoplastic invasion of the laryngeal cartilage may have important therapeutic implications. To our knowledge, no data are available comparing the impact of endoscopic examination, computed tomography (CT), and magnetic resonance (MR) imaging on pretherapeutic staging accuracy. The purpose of our study was to determine which imaging should be used as an adjunct to other clinical examinations in the pretherapeutic staging of laryngeal carcinoma.

METHODS

In this study, 40 consecutive patients with neoplasms of the larynx, who were treated surgically, were included in a prospective pretherapeutic staging protocol that included indirect laryngoscopy, direct microlaryngoscopy, contrast-enhanced CT, and gadolinium-diethylenetriamine pentaacetic acid-enhanced MR imaging at 1.5 Tesla. The surgical specimens were cut in whole-organ slices parallel to the plane of the axial CT and MR images. The histologic findings were compared with the clinical findings including the CT and MR images. The impact of each diagnostic method on pretherapeutic staging was analyzed.

RESULTS

Clinical/endoscopic evaluation failed to correctly stage 17 tumors due to invasion of the paraglottic space (1 tumor), preepiglottic space (2 tumors), and extralaryngeal soft tissues (14 tumors), resulting in a pretherapeutic staging accuracy of 57.5%. Neoplastic invasion of cartilage was present in 28 patients and absent in 12 patients. Although MR imaging was more sensitive in detecting neoplastic invasion of cartilage than CT (94% vs. 67%; P = 0.001), MR imaging was less specific than CT (74% vs. 87%; P = 0.007). There was no difference between the overall accuracy of CT and MR imaging in detecting neoplastic invasion of cartilage (80% vs. 82%). The accuracy of combined clinical/endoscopic examination and CT staging was 80% and the accuracy of combined clinical/endoscopic examination and MR imaging staging was 87.5%; the difference was not statistically significant.

CONCLUSIONS

Clinical/endoscopic examination alone failed to identify tumor invasion of the laryngeal cartilages and of the extralaryngeal soft tissues, resulting in a low staging accuracy (57.5%). Many pT4 (according to the International Union against Cancer TNM Staging System) tumors were clinically unrecognized. The combination of clinical/endoscopic evaluation and an additional radiologic examination, either CT or MR imaging, resulted in significantly improved staging accuracy (80% vs. 87.5%). MR imaging is significantly more sensitive but less specific than CT in detecting neoplastic cartilage invasion. Therefore, MR imaging tends to overestimate neoplastic cartilage invasion and may result in overtreatment, whereas CT tends to underestimate neoplastic cartilage invasion and may lead to inadequate therapy.

Laryngeal imaging by computerized tomography and magnetic resonance following radiation therapy: a need for caution

For patients with laryngeal tumours, the use of computerized tomography (CT) or magnetic resonance imaging (MR) may facilitate accurate staging by the demonstration of cartilage invasion or tumour extension to areas such as the pre-epiglottic space. The role of imaging in the follow-up of patients after radiotherapy, however, has not been examined. A prospective study of 18 patients undergoing laryngectomy was performed. The results of pre-operative CT and MR imaging were correlated with the pathological findings from whole organ axial sections of the laryngeal specimens. In five patients (28 per cent) both CT and MR images were significantly impaired by movement artefact. In the eight patients without previous radiotherapy, seven had adequate quality imaging and both CT and MR accurately demonstrated the site, size and extent of laryngeal tumour. In eight of the ten patients following radiation therapy the presence of tumour was correctly identified, however there was a poor correlation between the imaging and pathological findings. Two patients had radionecrosis alone. Neither CT nor MR imaging could differentiate between radionecrosis and recurrent tumour.

Trumpet maneuver for visual and CT examination of the pyriform sinus and retrocricoid area

The trumpet maneuver, a technique to inflate the hypopharynx with air, allows visualization of the pyriform sinuses and retrocricoid area during both fiberoptic examination and CT scanning. The technique is useful in delineating both normal and abnormal anatomy, and is especially useful in the evaluation of patients with hypopharyngeal symptoms in whom there is a low suspicion of anatomic disease. The methods, endoscopic photographs, and CT scan images are presented.

A method for routine approach to laryngeal and hypopharyngeal surgical specimens by whole organ sections in the horizontal plane

A procedure of pathological analysis of laryngopharyngeal specimens by whole organ sections in the horizontal plane was developed and evaluated. The use of a fast decalcifying and fixative solution allowed both an easier sectioning of the whole organ and thin (5-6 microns) histological whole organ sections of laryngo pharyngectomy specimens. The complete procedure required 5 to 10 days for each case. A preliminary examination of 39 surgical laryngopharyngectomy specimens with laryngeal or hypopharyngeal carcinomas showed that most of the normal structures were histologically identifiable on whole organ horizontal histological sections. The data of the local neoplastic spread related to the main sites of origin were in accordance with the results obtained by other studies using whole organ sections in the coronal or vertical planes. In conclusion, with this procedure it is possible to obtain, in a reasonably short time, thin histological horizontal whole organ sections allowing an adequate and complete assessment of the microscopic characteristics of the tumor and of the tridimensional relationships of the neoplasm with the host organ; moreover, by this procedure pathological data may be compared with preoperative CT or MR scans in patients with laryngeal and hypopharyngeal carcinomas.

Magnetic resonance imaging in head and neck cancer

The scans of 120 patients with proven head and neck cancer who underwent magnetic resonance imaging (MRI) at Mt. Vernon hospital were reviewed and, where possible, compared with their clinical, computed tomography (CT) and histological findings. MRI was generally superior to both clinical examination and CT in the detection of cervical lymphadenopathy and in the assessment of primary tumour extent, particularly in the tongue base, nasopharynx and parotid gland. Small intracranial tumour extensions were more readily detected by MRI than CT. MRI was no better than CT in distinguishing between malignant and inflamed tissues and was generally inferior to CT in spatial resolution, patient acceptance and examination cost.

Computed tomography in patients with laryngeal carcinoma: a clinical perspective

Among the various diagnostic modalities that have been recommended for preoperative assessment of the patient with laryngeal carcinoma is computed tomography. While good overall correlation between CT findings and operative findings has been noted, a significant number of false positives and false negatives have been found, particularly with regard to cartilage invasion and lymphadenopathy. We compared the findings of direct laryngoscopy, palpation of the neck, and CT with pathologic specimens in 29 patients who underwent surgery for carcinoma of the larynx. We found that CT scanning underestimated the extent of neoplastic involvement in over half the cases. With respect to cartilage invasion we determined a significant number of false-negative findings. Computed tomographic scanning was equivalent to palpation in predicting cervical metastasis. Our findings indicate that the role of CT scanning may be more limited than previously acknowledged, particularly in patients for whom nonconservation surgery is planned.

Magnetic resonance imaging of the larynx and tongue base: clinical applications

The use of surface coils on subjects, and internal engineering improvements have combined to greatly improve the signal-to-noise ratio on the magnetic resonance imager at our institution over the past two and one-half years. This has resulted in a marked improvement in image resolution, as well as reduction in the time required and related cost of these studies. Magnetic resonance (MR) examinations at our institution now cost less than comparable computed tomography (CT) studies. This article summarizes our experiences in imaging the larynx and tongue base. Eleven cases are presented to illustrate how the direct multiplane capacity of MRs and their increased soft tissue contrast provide some definite advantages over CT in determination of extent of disease in these regions.