Yoshimi Anzai

Evaluation of cervical lymph node metastases in squamous cell carcinoma of the head and neck

Although computed tomography and magnetic resonance imaging have contributed to the ability to identify metastatic disease in head and neck Cancer, inadequacies in evaluating lymphadenopathy still exist. This study was undertaken to estimate the accuracy of radiological criteria used to detect cervical lymph node metastases. The morphological characteristics of 957 lymph nodes from 36 neck dissections from patients with squamous cell Cancer were examined microscopically. A large number of malignant nodes were found to have diameters of less than 10 mm. Extranodal spread also occurred in a substantial percentage of smaller nodes. Because the present radiological criteria for assessing cervical lymph node Status are based largely on size, findings indicate major limitations in the capabilities of detecting metastatic disease. New modalities to improve the Staging of head and neck Cancer are discussed.

The use of positron emission tomography for early detection of recurrent head and neck squamous cell carcinoma in postradiotherapy patients

Positron emission tomography (PET) has recently proved to be highly sensitive in detecting known extracranial head and neck squamous cell carcinomas when compared to computed tomography and magnetic resonance imaging (MRI). The ability of PET to detect early subclinical recurrent squamous cell malignancies in patients who received primary radiotherapy was evaluated. A new PET‐MRI coregistration technique was used to determine precise anatomic tumor location, enabling directed biopsies to confirm the presence of malignancy, and to plan additional therapeutic strategies. Ten patients underwent PET evaluation with intravenous [18F]‐fluorodeoxyglucose and received postradiotherapy MRI scans. In all cases, PET accurately detected the presence of recurrent disease despite negative or equivocal MRI scans and indeterminate clinical examinations. PET appears to be highly effective in detecting early recurrent head and neck squamous cell malignancies in postirradiated patients.

Early postoperative appearance of radiofrequency lesions on magnetic resonance imaging.

Eleven patients who underwent stereotactic radiofrequency lesions in the central nervous system had magnetic resonance imaging follow-up within 72 hours of surgery to determine the early appearance of their lesions. Eight patients with severe tremor, one with chronic pain, and two with dystonia were analyzed. There were six female patients and five male patients, age 7 to 75 years (mean +/- standard deviation = 42 +/- 21). Magnetic resonance imaging was performed postoperatively at 32 +/- 25 hours (range, 3-72). Postoperative T1-weighted spin echo images demonstrated foci of iso- to hyperintensity surrounded by an edge of hypointensity, and corresponding T2-weighted images showed a lesion with three concentric zones consisting of inner hypointense, middle hyperintense, and outer hypointense zones. Gadolinium increased T1-weighted image lesion visibility, and a ring of enhancement around the zone of hypointensity was observed. Lesions could be seen as early as 3 hours after surgery. The lesions were best shown on gadolinium-enhanced T1-weighted images and on T2-weighted images. The edema surrounding the lesion increased over time, up to the 72 hours studied. These data provide important information on the development of lesion appearance, which may be applied in the development of real-time magnetic resonance imaging monitoring of radiofrequency lesion formation. This technique associated with electrophysiological response and the real-time visualization of the anatomic correlation of the probe may allow for a very precise and selected lesion in the central nervous system for the treatment of functional disorders and brain tumors.

Computer coregistration of positron emission tomography and magnetic resonance images in head and neck cancer

PURPOSEnEarly experience has shown that positron-emission tomography (PET) is a useful technique for the detection of occult squamous cell carcinoma of the head and neck. Although highly sensitive, PET lacks definition of anatomic detail and therefore does not localize pathology precisely. To circumvent this limitation, a computerized coregistration technique has been developed at the University of California-Los Angeles to correlate PET and magnetic resonance images (MRI). This method allows accurate, precise anatomic localization of areas of heightened glucose metabolism, including subclinical tumors.nnnMATERIALS AND METHODSnThe technique uses a coregistration computer program that precisely superimposes the PET scan with the corresponding MRI image.nnnRESULTSnTwo cases are presented in which PET-MRI coregistration was used to anatomically define the areas of heightened glucose metabolism. Large tumors were selected because the precision of the method can be verified.nnnCONCLUSIONnThe coregistration technique is a valuable addition to PET imaging, particularly in its ability to anatomically localize PET findings. The most important application of this technique is to facilitate the biopsy of subclinical lesions identified on PET.

Osteosarcoma metastatic to the larynx

Secondary laryngeal tumors are uncommon, accounting for approximately 0.02% of all laryngeal malignancies. 1,2 In 1988, Ferlito et all reviewed the world literature, which revealed 113 cases, and his series added another 7, for a total of 120 cases known at that time. We have identified 5 additional cases that have been reported.>? The most common primary tumors metastasizing to the larynx are melanomas of the skin (27% to 37%), renal cell carcinomas (13% to 17%), carcinomas of the breast (9% to 11%), lung carcinomas (8% to 11%), and adenocarcinomas of the prostate (6% to 7%).1,2,4 Thefollowing is the first case report known to us ofan osteosarcoma metastatic to the larynx.

New interventional room of the 1990s: how to upgrade a standard MR suite for minimally invasive surgery

A superconducting Signa 1.5 T magnetic resonance (MR) suite was modified and multiple upgrades were introduced to make it effective and safe for minimally invasive surgical procedures guided by imaging techniques. Two MR compatible video projection cameras and monitors from Resonance Technology were installed inside the Magnetic Resonance Imaging (MR) room allowing visualization of MR and/or ultrasound (UTZ) images during surgical procedures. The interventional therapist can now stand at the patients side and visualize MR and/or UTZ images in the room. A permanent MR compatible camera and light source were installed at the opening of the magnet bore which allows close-up visual monitoring of the patient and treatment site. MR compatible anesthesia systems (Ohmeda Company) and monitoring equipment (In Vivo Research, Inc.) are now available. A standard ultrasound (UTZ) system was modified and adapted by General Electric Medical Systems for use in this MRI suite.