Bradley A. Jabour

Positron emission tomography: A new, precise imaging modality for detection of primary head and neck tumors and assessment of cervical adenopathy

Positron emission tomography (PET) has been shown to be effective in detecting intracranial malignancies based on cerebral glucose metabolism. To evaluate the ability of PET to detect extracranial head and neck neoplasms and cervical metastases, 16 patients with primary squamous cell carcinomas were examined. All patients received preoperative computerized tomography (CT) and magnetic resonance imaging (MRI) scans and underwent PET evaluation using intravenous 18F‐2‐fluoro‐2‐deoxy‐D‐glucose (FDG). Histopathologic analysis compared tumor invasion and positive lymph nodes with findings on MRI, CT, and PET images. All primary tumors were delineated by PET, while MRI and CT failed to detect one superficial tumor involving the anterior tongue. Ten nodes were detected by CT and MRI versus 12 nodes demonstrated by PET. PET is highly effective in detecting head and neck carcinomas as well as metastatic cervical lymph nodes. In addition, PET may be useful in evaluating postsurgery and postradiotherapy patients for recurrent and new primary tumors.

Acute and Chronic Brain Injury in United States National Team Soccer Players

We designed a study to determine whether chronic encephalopathy occurs in elite, active soccer players resulting from repetitive heading of the soccer ball. Studies have suggested that the cumulative effects of heading a ball can cause a chronic brain syndrome similar to dementia pugilistica, which is seen in profes sional boxers. Twenty of 25 members of the U.S. Mens National Soccer Team training camp (average age, 24.9; average years of soccer, 17.7), who com pleted a questionnaire on head injury symptoms and had magnetic resonance imaging of the brain, were compared with 20 age-matched male elite track ath letes. The soccer players were surveyed about playing position, teams, number of headers, acute head inju ries, and years of playing experience. An exposure index to headers was developed to assess a dose- response effect of chronic heading. The soccer and track groups were questioned regarding alcohol use and history of acute head traumas. Questionnaire anal ysis and magnetic resonance imaging demonstrated no statistical differences between the two groups. Among the soccer players, symptoms and magnetic resonance imaging findings did not correlate with age, years of play, exposure index results, or number of headers. However, reported head injury symptoms, especially in soccer players, correlated with histories of prior acute head injuries (r = 0.63). These findings suggest that any evidence of encephalopathy in soccer players relates more to acute head injuries received playing soccer than from repetitive heading.

Positron emission tomography with fluorodeoxyglucose to evaluate tumor response and control after radiation therapy

PURPOSE Following radiation therapy, evaluation of viable tumor can often be difficult with anatomic imaging criteria (tumor size alone). In this study, the utility of biochemical imaging with the glucose analog 2-[F-18]fluoro-2-deoxy-D-glucose and positron emission tomography was investigated in patients treated with radiation therapy. METHODS AND MATERIALS Between 1990 and 1992, 19 patients were studied, including 15 patients with head and neck cancer, (4 oropharynx, 4 sinus, 3 larynx, 2 hypopharynx, 2 oral cavity [one patient], 1 nasopharynx), and 4 patients with breast cancer. Post-radiation positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose studies were done in all patients, with 9 head and neck patients receiving pre-radiation positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose scans as well. Results were correlated with other imaging techniques and pathology. RESULTS Positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose detected head and neck primary tumors and lymph node metastases in all nine pre-radiation scans, while magnetic resonance imaging failed to detect two primary tumors. Serial positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose showed a significant decrease in tumor activity after radiation therapy, compared to pre-radiation levels, (p < 0.05), except for two patients with increased uptake at the primary site. Biopsies of these two patients showed persistent/recurrent disease after radiation therapy, which was not detected by magnetic resonance imaging. Six additional head and neck patients, with suspicious examination and inconclusive magnetic resonance imaging, were imaged with positron emission tomography after radiation therapy only. Five patients had increased positron emission tomography activity, with corresponding biopsies positive in four patients, and negative in one patient with clinically worsening symptoms. The remaining sixth patient had minimal and stable positron emission tomography uptake, and is improving clinically. Four patients had mammogram findings suspicious for recurrence after conservation treatment for breast cancer. Positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose showed no focal activity in the breast in two patients, and increased activity in the area suspicious for recurrence in the other two patients. Biopsies correlated with positron emission tomography results. CONCLUSION Changes and presence of positron emission tomography with 2-[F-18]fluoro-2-deoxy-D-glucose activity correlated with pathologic findings in head and neck and breast cancer patients in this series. In patients with elevated or rising positron emission tomography activity after radiation therapy, persistent or recurrent disease was found in 89% of patients, (8/9). Magnetic resonance imaging did not detect the head and neck recurrences, and mammography was suspicious in patients with both benign and malignant breast changes after radiation therapy. In addition, our data indicate that in head and neck patients with pre-radiation positron emission tomography scans, a significant decrease in activity should occur after radiation therapy, if local control is to be expected.

Metastatic head and neck malignancy treated using MRI guided interstitial laser phototherapy: An initial case report

Interstitial laser phototherapy (ILP) guided by magnetic resonance imaging (MRI) may become an attractive adjunctive modality for the treatment of deep and surgically inaccessible tumors of the head and neck when accurate methods of laser dosimetry and “real‐time” monitoring techniques with the MRI are introduced. We recently demonstrated in ex vivo and in vivo models, a linear relationship between levels of laser energies, thermal profiles, MR signal intensity changes, and histopathological tissue damage. Results of treatment in a patient with an unresectable large right jugulodigastric metastatic squamous carcinoma using new approach of MRI guided ILP are now reported. The patient complained of significant right‐sided neck pain and headaches secondary to a rapidly growing metastatic lymphadenopathy which recurred after previous surgery, radiation, and chemotherapy. Two treatment sessions were used at an interval of 2 weeks. Each treatment was performed in the MRI suite under heavy sedation. Using a 600‐μm bare fiber of the Nd:YAG laser implanted interstitially under MR guidance, the metastatic node was treated at three sites. T1‐ and T2‐weighted images were performed prior to, immediately after, 24 and 48 hours, and 4, 5, 7, 9, 16, and 25 days post‐treatment. Successful relief of pain and growth arrest of this node was observed after the second treatment and at the 3‐month follow‐up. These results demonstrate that this technique of ILP guided by MRI may be feasible in humans, and will become clinically practical when appropriate methods of dosimetry and instrumentation are developed.

Interventional Magnetic Resonance Imaging in the Head and Neck

Interventional MRI is clearly in its early stages of development. While the value of MR-guided aspiration cytology and MR evaluation of deep electrode implantation in the brain has already been confirmed with human clinical studies, the future of MR-guided interstitial laser therapy remains to be proven. Despite this, as we look ahead into the 1990s and the millennium, it is possible to imagine dedicated MR laser therapy units for combined radiological and surgical outpatient approaches in what may become the operating rooms of the 21st century.

Magnetic resonance imaging of the larynx

The development of appropriate surface coils has resulted in outstanding depiction of the laryngeal anatomy using MRI. The multiplanar capability of MR allows superior definition of anatomy and tumor extent compared with CT scanning. MR appears to he more effective in detecting cartilage invasion. MR is as effective as CT in defining adenopathy and extension into the carotid sheath. MRI is therefore the primary modality in imaging the larynx.

Magnetic resonance imaging of the tongue and oropharynx.

In general. MRI produces superior soft tissue detail in evaluating the tongue and oropharynx lhan does CT. MRI is therefore considered the study of choice in this area. Lack of artifact from dental amalgam and beam hardening artifact from the mandible on MRI also eliminates two major shortcomings of CT in the examination of this area. Finally, the ability of MRI to obtain direct coronal and sagittal scan planes is a distinct advantage in recognizing intrinsic tongue musculature and assessing tumor volume and spread for treatment planning.

Magnetic resonance imaging of metastatic cervical adenopathy.

Detecting cervical adenopathy is critical in the management of carcinomas in head and neck. CT scanning remains a very effective modality in defining adenopathy. TI-weighted MRI scans are comparable to CT in detecting lymph nodes. T2-weighted images are less useful as the lymph nodes tend to have long T2 relaxation times similar to the surrounding fat. MR has not proved to be useful in detecting carcinoma in non-enlarged cervical nodes. The morphologic criteria developed for metastatic nodes with CT are appropriate with MRI (size, shape, signal, extracapsular spread). Gadolinium is sometimes useful in defining central necrosis in metastatic squamous cell adenopathy.

The use of surface coils for magnetic resonance-guided interventional procedures.

The advantages of surface coils for magnetic resonance imaging (MRI) of superficial structures include improvement in signal and decreased noise. There is now a growing use ofMRI to guide interventional procedures [1–4]. Because of the geometry of needles and other interventional devices, which extend outside the patient, optimal head receiver coils often cannot be used for imaging and the lower signal‐to‐noise body coil must be used because of its large size.