Chirag Patel

Functional Imaging for Radiation Treatment Planning, Response Assessment, and Adaptive Therapy in Head and Neck Cancer

Patients with squamous cell carcinomas (SCCs) of the head and neck are increasingly treated nonsurgically. Imaging plays a critical role in helping define the targets for radiation therapy, especially intensity-modulated radiation therapy, in which the dose gradients are steep. Anatomic imaging with conventional modalities, particularly computed tomography (CT), has been used in patients with head and neck SCCs, but this approach has limitations. Functional imaging techniques, including positron emission tomography (PET) combined with CT or magnetic resonance (MR) imaging, offer complementary information and can be used noninvasively to assess a range of biomarkers in patients with head and neck SCCs, including hypoxia, cell proliferation and apoptosis, and epidermal growth factor receptor status. These biologic markers can be monitored before, during, and after treatment to improve patient selection for specific therapeutic strategies, guide adaptation of therapy, and potentially facilitate more accurate assessment of disease response. This article discusses the practical aspects of integrating functional imaging into head-and-neck radiation therapy planning and reviews the potential of molecular imaging biomarkers for response assessment and therapy adaptation. The uses of PET tracers for imaging cellular processes such as metabolism, proliferation, hypoxia, and cell membrane synthesis are explored, and applications for MR techniques such as dynamic contrast material-enhanced imaging, diffusion-weighted imaging, blood oxygenation level-dependent imaging, and MR spectroscopy are reviewed. The potential of integrated PET/CT perfusion imaging and hybrid PET/MR imaging also is highlighted. These developments may allow more individualized treatment planning in patients with head and neck SCCs in the emerging era of personalized medicine.

Comparison of the diagnostic value of MR imaging and ophthalmoscopy for the staging of retinoblastoma

PurposeTo compare the diagnostic value of magnetic resonance (MR) imaging and ophthalmoscopy for staging of retinoblastoma.MethodsMR and ophthalmoscopic images of 36 patients who underwent enucleation were evaluated retrospectively following institutional review board approval. Histopathology being the standard of reference, the sensitivity and specificity of both diagnostic modalities were compared regarding growth pattern, iris neoangiogenesis, retinal detachment, vitreous seeds and optic nerve invasion. Data were analysed via McNemar’s test.ResultsBoth investigations showed no significant difference in accuracy for the detection of different tumour growth patterns (Pu2009=u20090.80). Vitreous seeding detection was superior by ophthalmoscopy (Pu2009<u20090.001). For prelaminar optic nerve invasion, MR imaging showed similar sensitivity as ophthalmoscopy but increased specificity of 40xa0% (CI 0.12–0.74) vs. 20xa0% (0.03–0.56). MR detected optic nerve involvement past the lamina cribrosa with a sensitivity of 80xa0% (0.28–0.99) and a specificity of 74xa0% (0.55–0.88). The absence of optic nerve enhancement excluded histopathological infiltration, but the presence of optic nerve enhancement included a high number of false positives (22–24xa0%).ConclusionsOphthalmoscopy remains the method of choice for determining extent within the globe while MR imaging is useful for evaluating extraocular tumour extension. Thus, both have their own strengths and contribute uniquely to the staging of retinoblastoma.Key Points• Ophthalmoscopy: method of choice for determining extent of retinoblastoma within the globe.• MR imaging provides optimal evaluation of extrascleral and extraocular tumour extension.• Positive enhancement of the optic nerve on MRI does not necessarily indicate involvement.

High-Resolution MR Imaging of the Orbit in Patients with Retinoblastoma

Retinoblastoma is the most common intraocular childhood malignancy, with a prevalence of one in 18,000 children younger than 5 years old in the United States. In 80% of patients, retinoblastoma is diagnosed before the age of three, and in 95% of patients, retinoblastoma is diagnosed before the age of five. Although reports exist of retinoblastoma in adults, onset beyond 6 years of age is rare. Broadly, retinoblastoma may be classified into two groups: sporadic and heritable. In either case, the origin of the tumor is a biallelic mutation in primitive neuroepithelial cells. Although their details vary, several staging schemes are used to describe the extent of retinoblastoma according to the following four general criteria: intraocular location, extraocular (extraorbital) location, central nervous system disease, and systemic metastases. In the past decade, substantial changes have taken place in terms of staging and monitoring treatment in patients with retinoblastoma. Diagnosis and treatment of retinoblastoma involve a multidisciplinary approach, for which imaging is a vital component. Increasing awareness and concerns about the effects of radiation in patients with retinoblastoma have led to a shift away from external-beam radiation therapy and toward chemotherapy and locoregional treatment, as well as the establishment of magnetic resonance imaging as the most important imaging modality for diagnosis, staging, and treatment monitoring.

Dynamic sonographic evaluation of posterior shoulder dislocation secondary to brachial plexus birth palsy injury.

onographic evaluation of hip dysplasia has been used since the early 1980s and is now a well-established procedure for the assessment and monitoring of neonatal and infantile hip stability. This same technology can be applied to glenohumeral joint evaluation. Computed tomography (CT) was the first radiographic modality to be used to describe shoulder instability in children with Erb palsy 25 years ago, 1 followed by magnetic resonance imaging

Neuroendocrine tumours of the head and neck: anatomical, functional and molecular imaging and contemporary management

Abstract Neuroendocrine tumours (NETs) of the head and neck are rare neoplasms and can be of epithelial or non-epithelial differentiation. Although the natural history of NETs is variable, it is crucial to establish an early diagnosis of these tumours as they can be potentially curable. Conventional anatomical imaging and functional imaging using radionuclide scintigraphy and positron emission tomography/computed tomography can be complementary for the diagnosis, staging and monitoring of treatment response. This article describes and illustrates the imaging features of head and neck NETs, discusses the potential future role of novel positron-emitting tracers that are emerging into clinical practice and reviews contemporary management of these tumours. Familiarity with the choice of imaging techniques and the variety of imaging patterns and treatment options should help guide radiologists in the management of this rare but important subgroup of head and neck neoplasms.

Sonographically Guided Enema for Intussusception Reduction A Safer Alternative to Fluoroscopy

Received June 7, 2012, from the Divisions of Pediatric Radiology (T.R.S.S., A.P., C.V.P.) and Pediatric Surgery (J.L.G., L.P.A.), University of California, Davis Children’s Hospital, Sacramento, California USA. Revision requested June 21, 2012. Revised manuscript accepted for publication July 16, 2012. Address correspondence to Thomas Ray S. Sanchez, MD, DepartmentofRadiology, University of California, Davis, 4860 Y St, Sacramento, CA 95817 USA. E-mail: thomas.sanchez@ucdmc.ucdavis.edu

The Foot and Ankle: MR Imaging of Uniquely Pediatric Disorders

MR imaging of the foot and ankle in children poses unique challenges, not only because of technical issues, but also because of the variations produced by age related changes. However, because of its excellent soft tissue contrast (especially helpful in delineating cartilage related abnormalities), MR imaging offers a distinct advantage over other imaging modalities. This article discusses MR imaging techniques for examining the pediatric foot and ankle, and reviews some common conditions encountered in a childs foot and ankle. This includes lesions such as osteochondritis dissecans; tarsal coalition; soft tissue and bony tumors of the foot and ankle; infection; and clubfoot.

Neuroblastoma of unknown primary site with periorbital bone metastasis in a child

Neuroblastoma is the second most common solid tumor in children. Most tumors arise in the adrenal glands or paravertebral region. Rarely, patients present with metastatic disease but no primary site can be found despite extensive imaging. We report here a patient with a large periorbital bone metastasis and bone marrow involvement but with no known primary site. Pediatr Blood Cancer.

Malignant rhabdoid tumor of the liver: findings at US, CT, and MRI with histopathologic correlation

Malignant rhabdoid tumors are aggressive malignancies that can rarely present as hepatic masses in the pediatric population. The imaging findings are often nonspecific and usually suggest other more common hepatic tumors. We report the radiologic appearance of malignant rhabdoid tumor in a 3-month-old female with pathologic correlation.

Radiotherapy response evaluation using FDG PET-CT—established and emerging applications

Radiation therapy is a common component of curative cancer treatment. However, there is a significant incidence of treatment failure. In these cases, salvage surgical options are sometimes appropriate. Accurate assessment of response and early recognition of treatment success or failure is therefore critical to guide treatment decisions and impacts on survival and the morbidity of treatment. Traditionally, treatment response has depended upon the anatomical measurement of disease. However, this may not correlate well with the presence of disease, especially after radiotherapy. Combined positron emission tomography (PET) and CT imaging employs radioactive tracers to identify molecular characteristics of tissues. PET imaging exploits the fact that malignancies have characteristic molecular profiles which differ compared with surrounding tissues. The complementary anatomical and functional information facilitates accurate non-invasive assessment of surrogate biomarkers of disease activity.