T. Thomas Zacharia

Central Nervous System Lymphoma Characterization by Diffusion‐Weighted Imaging and MR Spectroscopy

The characterization and differentiation of central nervous system (CNS) lymphoma has important diagnostic, therapeutic, and prognostic significance. The purpose of this study is to characterize the diffusion‐weighted imaging (DWI) and MR spectroscopic (MRS) findings in CNS lymphoma.

CT of colon cancer metastases to the liver using modified RECIST criteria: determining the ideal number of target lesions to measure.

OBJECTIVE We sought to define the ideal number of target lesions to be measured to assess disease response in patients undergoing chemotherapy for colon cancer metastases to the liver. MATERIALS AND METHODS Thirty consecutive patients were recruited for this study. Patients were part of a multisite, randomized, double-arm, phase 3 clinical trial involving chemotherapy with an investigational drug for metastatic colon cancer. Patients were recruited from U.S. and international sites. Institutional review board approval was obtained, and informed consent was obtained from all patients. Our study included CT measurements of hepatic metastases. All patients (n = 30) had a minimum of five target lesions in the liver. Target-lesion size was defined by Response Evaluation Criteria in Solid Tumors (RECIST) criteria. We calculated the patient response at 2 months and at 6 months (complete response, partial response, stable disease, and progressive disease) using RECIST. Patient response was calculated based on the percentage increase or decrease at 2 and 6 months in the greatest diameter of the single largest lesion, two large lesions, three large lesions, four lesions, and five lesions, respectively. The concordance between five-target-lesion measurement and lesser numbers of lesions was analyzed using kappa statistics (StatView, 5.0). RESULTS In 93.33% of patients (n = 28/30), there was agreement on patient response irrespective of the number of measurements made on CT. Of these 30 patients, 47% had a partial response (n = 14/30), 43% had stable disease (n = 13/30), and 10% had progressive disease at 2 months (n = 3/30). At 6 months, 43% had a partial response (n = 13/30), 47% had stable disease (n = 14/30), and 10% had progressive disease (n = 3/30). Agreement in response evaluation between lesion groups for multiple measurements was high, with values of 1.0 for multiple-lesion measurements and 0.88 for single-lesion measurements at 2 months. The concordance values were the same at 6 months. CONCLUSION In the majority of patients with hepatic metastases of colorectal cancer, measuring the maximal diameter of the single largest lesion yielded the same treatment-response classification as measuring up to five target lesions. This result suggests that it may be possible to reduce the number of lesions measured in clinical trials.

Differentiation of branchial cleft cysts and malignant cystic adenopathy of pharyngeal origin.

OBJECTIVE There is an increasing incidence of head and neck cancers that present as neck masses in a nonsmoking nondrinking population. These masses can be confused with benign cystic neck masses. The purpose of this study was to determine imaging criteria to differentiate benign lateral neck cysts from malignant cystic adenopathy. MATERIALS AND METHODS A retrospective analysis of patients who underwent contrast-enhanced neck CT between July 2003 and July 2011 was performed. Patients were diagnosed with either a branchial cleft cyst or pharyngeal squamous cell cancer. Each examination was reviewed by a neuroradiologist, and, for each cyst or cystic lymph node, the anatomic level in the neck, dimensions, wall thickness, septations, homogeneity, extracapsular spread, calcifications, and fat stranding were recorded. Data analysis was performed using Student t tests and chi-square tests. RESULTS Twenty-one patients with branchial cleft cysts and 29 patients with squamous cell carcinoma met the inclusion criteria. Significant differences between the groups were found with regard to size, homogeneity, and extracapsular spread. Branchial cleft cysts were found to be larger on the long axis (p < 0.001), short axis (p < 0.001), and height (p < 0.001). They were less likely to have extracapsular spread (p = 0.044) or septations (p = 0.059) and more likely to be homogeneous (p < 0.001). CONCLUSION Misdiagnosis of malignant cysts in the neck may lead to delay in diagnosis, a violated neck, tumor spillage, and spread. Differences in radiographic criteria can guide clinical decision making in the patient with a neck mass. However, fine-needle aspiration may be necessary to confirm the diagnosis.

Optimization of patient dose and image quality with z-axis dose modulation for computed tomography (CT) head in acute head trauma and stroke

The purpose of this study is to retrospectively analyze the effect of z-axis modulation for CT head protocols on patient dose and image quality in patients with acute head trauma and stroke. The study was approved by the Institutional Review Board. We retrospectively evaluated the effect of dose modulation on unenhanced CT head examinations in patients with acute head trauma and stroke. Two series of 100 consecutive studies were reviewed: 100 studies performed without dose modulation, 100 studies performed with z-axis dose modulation. Multidetector 16-section CT was performed sequentially and axial 5-mm-thick slices were obtained from base of skull to vertex. With z-axis dose modulation, the same tube current range was maintained, but a computer algorithm altered the tube current applied to each CT section. For each examination, the weighted volume CT dose index (CTDI (vol)) and dose-length product (DLP) were recorded and noise was measured. Each study was also reviewed for image quality by two independent, blinded readers. The variables (CTDI (vol) and DLP, image quality, and noise) in the two groups were compared by using student t test and Wilcoxon rank-sum test. For unenhanced CT head examinations, the CTDI (vol) and DLP, respectively, were reduced by 35.8% and 35.2%, respectively, by using z-axis dose modulation. Image quality and noise were unaffected by the use of this dose modulation technique (P < 0.004). Utilization of z-axis modulation technique for CT head examination in patients with acute head trauma and stroke offers significant radiation dose reduction while image quality is optimally maintained.

Parotid Space: Anatomic Imaging

The authors present imaging anatomy of the parotid space and discuss non-neoplastic lesions, autoimmune disorders, cysts, neoplastic lesions, epithelial tumors, and nonepithelial lesions. They describe the diseases and their appearance on imaging, describing how the differential diagnoses appear, along with presenting examples of the images, primarily computed tomography and magnetic resonance imaging.

The effect of aging on the anatomic position of the thyroid gland

Thyroid disease is common among elderly patients, frequently necessitating thyroid gland examination, imaging, and surgery. However, no prior studies have determined the effect of age on the anatomic position of the thyroid gland in the anterior neck. We hypothesized that the thyroid gland resides at a more caudal position in the neck in elderly patients as compared to younger patients. Head and neck CT scans were collected from 122 atraumatic patients without thyroid disease aged 18–39 years, 40–59 years, 60–79 years, and 80+ years. Measurements of thyroid gland position and other aspects of head and neck anatomy were conducted in the mid‐sagittal plane. The distance between the thyroid gland and the sternal notch decreased from 45 ± 10.4 mm in the 18–39 age group to 30.8 ± 9 mm in the 80+ age group (P < 0.001). The position of the gland did not change significantly relative to anatomic landmarks in the head or neck, although the trachea was angled more closely to the horizontal plane in elderly patients (P < 0.001). Cervical spine height was also lower among patients ≥60 years of age compared to those <60 years of age (P < 0.001). Multivariate linear modeling suggested that thyroid gland position was dependent on changes in cervical spine height, hyoid bone to hard palate distance, and tracheal angle (P = 1.7 × 10−11; r2 = 0.37). Clinicians should be aware of the more caudad positioning of the gland when planning surgery or screening for thyroid disease in the elderly. Clin. Anat. 30:205–212, 2017.

Multiple adult rhabdomyomas of the oropharynx, base of the tongue, and floor of the mouth: magnetic resonance findings.

Adult rhabdomyomas of the head and neck are uncommon, benign neoplasms that usually present as asymptomatic solitary lesions in the oral cavity, pharynx, or larynx. Rarely do rhabdomyomas occur in multiple sites. We describe the magnetic resonance (MR) imaging appearance of multiple adult rhabdomyomas synchronously involving the floor of the mouth, base of the tongue, and oropharynx in a 70-year-old man.

Development and standardization of tinnitus handicap inventory in Kannada.

INTRODUCTION Tinnitus Handicap Inventory (THI) was developed in English to quantify the handicap caused due to tinnitus. According to a survey conducted by USA, 40 million people are affected by tinnitus. OBJECTIVES India being a multilingual country needs to develop and standardize THI in Indian languages. The present study concentrates on Developing and Standardizing THI in Kannada. MATERIALS AND METHODS Questions from English version of THI were translated and modified by two professionals who have a degree of MA Kannada. Translated inventory was given to 50 native Kannada speakers for the familiarity check & the most familiar sentences were included in the study. Tinnitus questionnaire was then administered, followed by the Kannada version of THI on 140 patients and total scores were obtained. RESULTS Analysis revealed 14% of the patients fall under the category of Slight, 38% under Mild, 26% under Moderate, 16% under Severe and 6% under Catastrophic group. An item total correlation and Cronbach-alpha test was administered to examine the reliability measures and the scores were 0.883 and 0.885 on standardized item. CONCLUSION Scores of Cronbach-alpha test shows that Kannada version of THI is a standard and reliable tool for measuring the handicap caused by tinnitus and can successfully classify individuals on a severity basis.

Epstein-Barr virus encephalitis presenting as cerebellar hemorrhage.

Epstein–Barr virus (EBV) belongs to the human herpesvirus family and is ubiquitously found in the adult human population. The most common clinical manifestation of EBV is the syndrome of infectious mononucleosis. Central nervous system involvement by EBV is rare, with very few cases of EBV encephalitis reported in the literature. The majority of these cases report cerebral cortical changes on magnetic resonance imaging. We present a rare case of EBV encephalitis in a young patient with meningitis-like symptoms and cerebellar hemorrhage on magnetic resonance imaging.

Imaging of neonatal brain emergencies: multisequence MRI analysis of pathologic spectrum including diffusion and MR spectroscopy

The purpose of this pictorial essay is to review the normal neonatal brain MR anatomy and the MR imaging appearances of neonatal brain emergencies and discuss the advantages of individual MR imaging sequences and the clinical implications of utilizing MRI as a problem-solving modality in the neonatal intensive care unit. Here we briefly discuss the normal MR imaging anatomy and myelination pattern and normal MR spectroscopy findings in a neonate. The role of individual MR imaging sequences in evaluating various neonatal abnormalities is being emphasized. For example, the utility of diffusion-weighted imaging for the diagnosis of profound hypoxic–ischemic injury and other forms of hypoxic–ischemic encephalopathies and MR spectroscopy in the diagnosis of metabolic encephalopathies and genetic disorders including aminoacidurias is being presented.