Franz J. Wippold

DETERMINATION AND DELINEATION OF NODAL TARGET VOLUMES FOR HEAD-AND-NECK CANCER BASED ON PATTERNS OF FAILURE IN PATIENTS RECEIVING DEFINITIVE AND POSTOPERATIVE IMRT

PURPOSE We present the guidelines for target volume determination and delineation of head-and-neck lymph nodes based on the analysis of the patterns of nodal failure in patients treated with intensity-modulated radiotherapy (IMRT). METHODS AND MATERIALS Data pertaining to the natural course of nodal metastasis for each head-and-neck cancer subsite were reviewed. A system was established to provide guidance for nodal target volume determination and delineation. Following these guidelines, 126 patients (52 definitive, 74 postoperative) were treated between February 1997 and December 2000 with IMRT for head-and-neck cancer. The median follow-up was 26 months (range 12-55), and the patterns of nodal failure were analyzed. RESULTS These guidelines define the nodal target volume based on the location of the primary tumor and the probability of microscopic metastasis to the ipsilateral and contralateral (Level I-V) nodal regions. Following these guidelines, persistent or recurrent nodal disease was found in 6 (12%) of 52 patients receiving definitive IMRT, and 7 (9%) of 74 patients receiving postoperative IMRT had failure in the nodal region. CONCLUSION On the basis of our clinical experience in implementing inverse-planning IMRT for head-and-neck cancer, we present guidelines using a simplified, but clinically relevant, method for nodal target volume determination and delineation. The intention was to provide a foundation that enables different institutions to exchange clinical experiences in head-and-neck IMRT. These guidelines will be subject to future refinement when the clinical experience in head-and-neck IMRT advances.

Diffusion-weighted MR imaging in the preoperative assessment of brain abscesses.

BACKGROUND Diffusion-weighted MR imaging (DWI) has recently shown promise in differentiating ring-enhancing lesions such as brain abscess and malignant neoplasm. The ability of DWI to strongly suggest brain abscess enables a neurosurgeon to alter stereotactic planning to optimize diagnosis. We report our experience with DWI in 5 patients with lesions on MR imaging and review the literature to assess the usefulness of this technique in the preoperative evaluation of cerebral abscess. METHODS The MR images of 5 patients presenting with ring-enhancing lesions that ultimately proved to be brain abscesses were retrospectively reviewed. In addition to standard MR sequences, trace DWI and apparent diffusion coefficient (ADC) calculations were performed on all patients. Additionally, 15 recently published articles or references in press concerning DWI in cerebral abscesses were reviewed. RESULTS All lesions were markedly hyperintense on DWI and had diminished ADC. Thirty-eight of 39 previously reported abscesses were hyperintense on DWI with reduced ADC. Of 165 nonpyogenic lesions with DWI findings, 87 were hypointense or isointense, 78 lesions had variable hyperintensities, and few manifested the degree of hyperintensity observed with abscesses. Most of these included chordomas and epidermoids, which are not likely to be confused with abscesses. CONCLUSIONS Restricted water diffusion, as indicated by hyperintensity on DWI and low ADC, in ring-enhancing lesions assists in differentiating brain abscess from necrotic tumor. This information facilitates stereotactic surgical planning: abscesses should be preferentially centrally aspirated, whereas necrotic brain tumors should have diagnostic tissue biopsied from cavity walls. Although not definitive for brain abscess, restricted water diffusion is an important MR imaging sign and is useful in neurosurgical treatment strategies for ring-enhancing lesions.

Practical selection criteria for noncontrast cranial computed tomography in patients with head trauma

STUDY OBJECTIVE To study patients with acute trauma retrospectively for clinical predictors of positive cranial computed tomography. METHODS We reviewed the medical records and noncontrast computed tomography scans of 373 consecutive head trauma patients presenting to a trauma Level I emergency department. Potential criteria for patient selection were analyzed statistically, using both univariate and multivariate models. RESULTS Our data suggest that relying on four variables--positive neurologic examination, intoxication, and a history of amnesia or focal neurologic deficit--as screening criteria for computed tomography would have saved 58.6% of the scans performed on these patients. Together, these criteria had a sensitivity of 90.1% and a negative predictive value of 98.1% for abnormal computed tomography. Four patients with positive scans would not have been detected using this strategy. None of these patients deteriorated clinically or required operative intervention. CONCLUSION Our data suggest that it may be possible to effectively screen patients with head trauma for cranial computed tomography using clinical criteria and so reduce the current number of scans performed by more than half. However, a prospective study is required to confirm our results.

Neuropathology for the Neuroradiologist: Antoni A and Antoni B Tissue Patterns

SUMMARY: Histologic patterns of cellular architecture often suggest a tissue diagnosis. Distinctive histologic patterns seen within the peripheral nerve sheath tumor schwannoma include the Antoni A and Antoni B regions. The purpose of this report is to review the significance of Antoni regions in the context of schwannomas.

Contrast-Enhanced MR Imaging of Brain Lesions: A Large-Scale Intraindividual Crossover Comparison of Gadobenate Dimeglumine versus Gadodiamide

BACKGROUND AND PURPOSE: The higher relaxivity of gadobenate dimeglumine compared with gadodiamide is potentially advantageous for contrast-enhanced brain MR imaging. This study intraindividually compared 0.1-mmol/kg doses of these agents for qualitative and quantitative lesion enhancement. MATERIALS AND METHODS: Adult patients with suggested or known brain lesions underwent 2 identical MR imaging examinations at 1.5T, one with gadobenate dimeglumine and the other with gadodiamide. The agents were administered in randomized order separated by 3–14 days. Imaging sequences and postinjection acquisition timing were identical for the 2 examinations. Three blinded readers evaluated images qualitatively for diagnostic information (lesion extent, delineation, morphology, enhancement, and global preference) and quantitatively for contrast-to-noise ratio (CNR). RESULTS: One hundred thirteen of 138 enrolled patients successfully underwent both examinations. Final diagnoses were intra-axial tumor, metastasis, extra-axial tumor, or other (47, 27, 18, and 21 subjects, respectively). Readers 1, 2, and 3 demonstrated global preference for gadobenate dimeglumine in 63 (55.8%), 77 (68.1%), and 73 (64.6%) patients, respectively, compared with 3, 2, and 3 patients for gadodiamide (P < .0001, all readers). Highly significant (P < .0001, all readers) preference for gadobenate dimeglumine was demonstrated for all qualitative end points and for CNR (increases of 23.3%–34.7% and 42.4%–48.9% [spin-echo and gradient-refocused echo sequences, respectively] for gadobenate dimeglumine compared with gadodiamide). Inter-reader agreement was good for all evaluations (κ = 0.47–0.69). Significant preference for gadobenate dimeglumine was demonstrated for all lesion subgroup analyses. CONCLUSION: Significantly greater diagnostic information and lesion enhancement are achieved on brain MR imaging with 0.1-mmol/kg gadobenate dimeglumine compared with gadodiamide at an equivalent dose.

Association between Annular Tears and Disk Degeneration: A Longitudinal Study

BACKGROUND AND PURPOSE: Annular tears and nuclear degeneration often occur concurrently, but their temporal association remains unknown. The purpose of this study was to assess whether annular tears precede nuclear degeneration and whether the evolution of nuclear degeneration is affected by presence of annular tears. MATERIALS AND METHODS: From our radiology report data base, 46 patients with back pain were identified, each with 2 previously obtained lumbar spine MR imaging examinations in the absence of any spinal intervention. Two neuroradiologists evaluated intervertebral disks between the T12 and S1 segments in a random blinded fashion. Hyperintense foci within the anulus were noted to diagnose annular tears. The signal intensity of disks was graded on an ordinal scale, and overall degeneration, on the scale of Pfirrmann et al. Mean signal-intensity and degeneration grades were calculated for disks with and without annular tears, and differences were tested for statistical significance. Mean changes in these grades on follow-up studies were also calculated and compared for 2 groups. RESULTS: The study included 13 men and 33 women, with a mean age of 53.6 ± 15.2 years (range, 20–88 years). The mean interval between the imaging studies was 31.8 months. Annular tears were seen in 203 of 276 (73.5%) disks. Twenty-one of these had normal central signal intensity. Compared with disks without annular tears, disks with annular tears demonstrated significantly higher degeneration grades and a higher change in these grades on follow-up. CONCLUSIONS: Annular tears occur in the early stages of disk degeneration and are associated with a faster subsequent nuclear degeneration.

American College of Radiology appropriateness criteria on multiple brain metastases.

EXPERT PANEL ON RADIATION ONCOLOGY–BRAIN METASTASES; GREGORY M. M. VIDETIC, M.D.,* LAURIE E. GASPAR, M.D., M.B.A.,y AMR M. AREF, M.D.,z ISABELLE M. GERMANO, M.D.,x BRIAN J. GOLDSMITH, M.D.,k JOSEPH P. IMPERATO, M.D.,{ KAREN J. MARCUS, M.D., MICHAEL W. MCDERMOTT, M.D.,** MARK W. MCDONALD, M.D.,yy ROY A. PATCHELL, M.D.,zz H. IAN ROBINS, M.D., PH.D.,xx C. LELAND ROGERS, M.D.,kk JOHN H. SUH, M.D.,* AARON H. WOLFSON, M.D.,{{ AND FRANZ J. WIPPOLD, II, M.D.

Prospective Cohort Study of Nephrogenic Systemic Fibrosis in Patients With Stage 3–5 Chronic Kidney Disease Undergoing MRI With Injected Gadobenate Dimeglumine or Gadoteridol

OBJECTIVE The purpose of this study was to determine the incidence of nephrogenic systemic fibrosis (NSF) in patients with chronic kidney disease (CKD) and moderate-to-severe impairment of kidney function who had not previously been exposed to gadolinium-based contrast agents (GBCAs) or referred to undergo contrast-enhanced MRI with gadobenate dimeglumine or gadoteridol. SUBJECTS AND METHODS Two multicenter prospective cohort studies evaluated the incidence of unconfounded NSF in patients with stage 3 CKD (estimated glomerular filtration rate [eGFR] in cohort 1, 30-59 mL/min/1.73 m(2)) or stage 4 or 5 CKD (eGFR in cohort 2, < 30 mL/min/1.73 m(2)) after injection of gadobenate dimeglumine (study A) or gadoteridol (study B). A third study (study C) determined the incidence of NSF in patients with stage 4 or 5 CKD who had not received a GBCA in the 10 years before enrollment. Monitoring for signs and symptoms suggestive of NSF was performed via telephone at 1, 3, 6, and 18 months, with clinic visits occurring at 1 and 2 years. RESULTS For studies A and B, the populations evaluated for NSF comprised 363 and 171 patients, respectively, with 318 and 159 patients in cohort 1 of each study, respectively, and with 45 and 12 patients in cohort 2, respectively. No signs or symptoms of NSF were reported or detected during the 2 years of patient monitoring. Likewise, no cases of NSF were reported for any of the 405 subjects enrolled in study C. CONCLUSION To our knowledge, and consistent with reports in the literature, no association of gadobenate dimeglumine or gadoteridol with unconfounded cases of NSF has yet been established. Study data confirm that both gadoteridol and gadobenate dimeglumine properly belong to the class of GBCAs considered to be associated with the lowest risk of NSF.

MRI of esthesioneuroblastoma.

Objective Esthesioneuroblastomas are uncommon tumors originating in the olfactory epithelium of the superior nasal cavity. Accurate staging appropriately guides therapy and predicts survival. The MR appearance and pattern of contrast enhancement in these tumors have not been well described. The goals of this article were to analyze the MRI characteristics of esthesioneuroblastoma, including extent of tumor, differentiation from obstructive sinus disease, MR signal, and pattern of contrast enhancement. Materials and Methods The MR examinations of six patients with proven advanced esthesioneuroblastoma were reviewed. Standard SE T1− and T2-weighted axial images were obtained [550–600/15–25 and 2,000–2,760/80–90 (TR/TE), respectively], followed by postcontrast axial and coronal T1-weighted sequences in all patients. Results Five of the six tumors were centered in the superior nasal cavity and one was centered in the lateral ethmoid air cells. Five tumors extended intracranially. Postobstructive sinus disease was always encountered. As compared to gray matter, the signal on T1-weighted images was either hypo- or isointense. On T2-weighted images, the signal varied from iso- to hyperintensity. Contrast enhancement was intense and of variable uniformity. Conclusion Magnetic resonance signal characteristics helped to distinguish obstructive sinus disease from tumor. The MR signal characteristics and pattern of contrast enhancement were nonspecific for esthesioneuroblastoma. Enhanced images, particularly in the coronal plane, were very helpful in identifying intracranial extension.

ACR Appropriateness Criteria®: Single Brain Metastasis

Single brain metastasis represents a common neurologic complication of cancer. Given the number of treatment options that are available for patients with brain metastasis and the strong opinions that are associated with each option, appropriate treatment for these patients has become controversial. Prognostic factors such as recursive partitioning analysis and graded prognostic assessment can help guide treatment decisions. Surgery, whole brain radiation therapy (WBRT), stereotactic radiosurgery or combination of these treatments can be considered based on a number of factors. Despite Class I evidence suggestive of best therapy, the treatment recommendation is quite varied among physicians as demonstrated by the American College of Radiologys Appropriateness Panel on single brain metastasis. Given the potential concerns of the neurocognitive effects of WBRT, the use of SRS alone or SRS to a resection cavity has gained support. Since aggressive local therapy is beneficial for survival, local control and quality of life, the use of these various treatment modalities needs to be carefully investigated given the growing number of long-term survivors. Enrollment of patients onto clinical trials is important to advance our understanding of brain metastasis.