Quantifying Tumor and Vasculature Deformations during Laryngoscopy.

Retractors and scopes used in head and neck surgery to provide adequate surgical exposure also deform critical structures in the region. Surgeons typically use preoperative imaging to plan and guide their tumor resections, however the large tissue deformation resulting from placement of retractors and scopes reduces the utility of preoperative imaging as a reliable roadmap. We quantify the extent of tumor and vasculature deformation in patients with tumors of the larynx and pharynx undergoing diagnostic laryngoscopy. A mean tumor displacement of 1.02 cm was observed between the patients' pre- and intra-operative states. Mean vasculature displacement at key bifurcation points was 0.99 cm. Registration to the hyoid bone can reduce tumor displacement to 0.67 cm and improve carotid stem angle deviations but increase overall vasculature displacement. The large deformation results suggest limitations in reliance on preoperative imaging and that using specific landmarks intraoperatively or having more intraoperative information could help to compensate for these deviations and ultimately improve surgical success.

Diagnosis and management of oral cavity lipoblastoma and lipoblastomatosis in an 8-month-old boy.

Lipoblastoma/lipoblastomatosis presents some unique diagnostic and therapeutic challenges when encountered in the oral cavity. In these rare cases, diagnostic confirmation with molecular testing and a conservative surgical resection can contribute to successful management.

PET Imaging of Tumor Hypoxia in Head and Neck Cancer: A Primer for Neuroradiologists.

Tumor hypoxia is a known independent prognostic factor for adverse patient outcomes in those with head and neck cancer. Areas of tumor hypoxia have been found to be more radiation resistant than areas of tumor with normal oxygenation levels. Hypoxia imaging may serve to help identify the best initial treatment option and to assess intratreatment monitoring of tumor response in case treatment changes can be made. PET imaging is the gold standard method for imaging tumor hypoxia, with 18F-fluoromisonidazole the most extensively studied hypoxic imaging tracer. Newer tracers also show promise.

PRE-OPERATIVE LOCALIZATION OF PARATHYROID ADENOMA: PERFORMANCE OF 4D MRI PARATHYROID PROTOCOL.

Objective: Accurate pre-operative image localization is critical in the selection of minimally invasive parathyroidectomy as a surgical treatment approach in patients with primary hyperparathyroidism (PHPT). Sestamibi scan, ultrasound, computed tomography, and conventional magnetic resonance imaging (MRI) has varying accuracy in localizing parathyroid adenoma (PTA). Our group has previously shown that four-dimensional (4D) MRI is more accurate than conventional imaging in identifying single adenomas. In this study, we set out to determine if it is possible to accurately localize the quadrant of the adenoma using 4D MRI. Methods: We analyzed and matched the quadrants of PTA identified by pre-operative 4D-MRI with the operative findings during parathyroidectomy for PHPT at our institution during the study period. All resections were confirmed to be successful with an adequate decrease in intraoperative parathyroid hormone as defined by the Miami criterion. Results: A total of 26 patients with PHPT underwent pre-operative localization with the 4D MRI parathyroid protocol. Fourteen patients had true single-gland adenoma (SGA) and 12 patients had multi-gland disease (MGD). 4D MRI accurately identified all the SGA. Using this method, we were also able to localize the adenoma in the correct quadrant in 14 of the 18 patients with SGA. All 3 double adenomas were accurately identified using 4D MRI; however, MGD was only accurately identified 67% of the time. The 4D MRI had an overall 85% accuracy in distinguishing SGA from MGD. Conclusion: 4D MRI accurately identified single and double adenomas in their respective quadrants. However, accuracy was lower with MGD. Abbreviations: BNE = bilateral neck exploration; CT = computed tomography; IOPTH = intra-operative parathyroid hormone; MGD = multi-gland disease; MIBI = sestamibi; MIP = minimally invasive parathyroidectomy; MRI = magnetic resonance imaging; PHPT = primary hyperparathyroidism; PTA = parathyroid adenoma; PTH = parathyroid hormone; SGA = single-gland adenoma; SPECT = single photon emission computed tomography; 4D = four-dimensional.

Bilateral persistent primitive hypoglossal artery presenting with hemiplegia✰.

The manuscript describes an unusual vascular anomaly. Persistence of carotid-vertebrobasilar anastomosis is a rare occurrence with presence of bilateral hypoglossal arteries (HAs) rarer still. We present a case of bilateral persistent HAs with hypoplastic vertebral arteries which end into posterior inferior cerebellar arteries. The computed tomography and magnetic resonance imaging appearance, course, and other associations are discussed. A review of 6 cases of bilateral HA published in the world literature is also discussed.

The First Reported Case of Recurrent Carcinoid Tumor in the External Auditory Canal.

OBJECTIVE: Cutaneous neuroendocrine lesions of the external auditory canal (EAC) are exceptionally rare, with only five cases reported in the literature. In this case report, we present a patient with a recurrent carcinoid tumor in the EAC, which has yet to be described. PATIENTS: A 38-year-old woman presenting with otalgia, aural fullness, and decreased hearing was found to have a recurrent EAC carcinoid tumor, 8-years after initial resection at an outside facility. INTERVENTIONS: The recurrent tumor involved much of the proximal, anterior bony ear canal and was trans-tympanic, extending to the middle ear and epitympanum; therefore, a lateral temporal bone resection was performed to ensure complete resection. MAIN OUTCOME MEASURES: Surgical pathology confirmed the presence a recurrent carcinoid tumor in the EAC, with immunohistochemistry positive for pancytokeratin (MAK6), CD56, and synaptophysin, with chromogranin showing rare cells positive for cytoplasmic granules. There was no evidence of metastasis. RESULTS: Lateral temporal bone resection was successful and the patient is being followed with annual imaging. The patient is considering future hearing rehabilitation with a bone anchored hearing device. CONCLUSION: This case report highlights the first known case of recurrent carcinoid tumor in the EAC, treated with lateral temporal bone resection. Clinical presentation, imaging, treatment, and pathology are reviewed along with a review of the literature.

Chordoma dedifferentiation after proton beam therapy: a case report and review of the literature.

BACKGROUND: Chordoma is a rare invasive bone tumor that may occur anywhere along the neuraxis. A total of three primary histological varieties have been identified: conventional, chondroid, and dedifferentiated. CASE PRESENTATION: We report a case of an 8-year-old white girl who presented with conventional chordoma, was treated with surgical resection and mixed proton and photon beam therapy, and had a recurrence in the resection cavity 2.5 years later with dedifferentiated morphology. The recurrent tumor did not express brachyury, a recently identified protein specific to tissue of notochordal origin. CONCLUSIONS: The short time period between radiation therapy and dedifferentiation, low dose of photons, and rarity of dedifferentiated skull base chordomas in pediatric patients should alert clinicians to the possibility of chordoma dedifferentiation after proton beam therapy.

A Diagnostic Dilemma: Multiple Primary Intracranial Tumors Without Vestibular Schwannomas.

Sinonasal schwannomas with intracranial extension are exceedingly rare, with only 7 cases reported in the literature. Schwannomas can be isolated or multiple and are commonly associated with familial disorders such as neurofibromatosis 2 (NF 2) or familial schwannomatosis or in sporadic cases seen in sporadic schwannomatosis. Nearly all people with NF2 older than 30 years of age will have the hallmark of bilateral vestibular schwannomas (VS). This case highlights a reported case of an adult with separate primary intracranial tumors. We review the diagnostic criteria of NF2 and schwannomatosis, a recently described third variant of neurofibromatosis. In this case, we incorporate family history, histopathology, and the pathophysiology of both disorders to help determine a diagnosis for this patient.

MRI Contrast Agents: Evolution of Clinical Practice and Dose Optimization.

Accurate detection of lesions throughout the body is of paramount importance in contrast-enhanced magnetic resonance imaging (MRI). Optimal contrast agent performance is therefore of great importance and given the number of MRI contrast agent options today, this topic is of much ongoing study. The goal of this review article is to bring the read up to date on pertinent articles that relate to the evolution of radiological clinical practice and dose optimization pertaining to gadolinium contrast agents.

Metastatic Prostate Cancer to the Left Temporal Bone: A Case Report and Review of the Literature.

Breast, lung, and prostate cancers are the three most common malignancies to metastasize to the temporal bone. Still, metastatic prostate cancer of the temporal bone is a rare finding, with approximately 21 cases reported in the literature and only 2 cases discovered more than 10 years after initial treatment of the primary. This disease may be asymptomatic and discovered incidentally; however, hearing loss, otalgia, cranial nerve palsies, and visual changes can all be presenting symptoms. We present the case of a 95-year-old man with history of primary prostate cancer treated 12 years earlier that was seen for new-onset asymmetric hearing loss and otalgia. The tympanic membranes and middle ears were normal; however, based on radiologic findings and eventual biopsy, the patient was diagnosed with extensive metastatic prostate cancer to the left temporal bone. This case (1) demonstrates that a high index of suspicion for unusual etiologies of seemingly benign symptoms must be maintained in elderly patients having prior history of cancer and (2) substantiates the value of temporal bone imaging when diagnosis may be unclear from history and physical exam.

The Solid Component of Radiographically Non-Growing, Post-Radiated Vestibular Schwannoma Retains Proliferative Capacity: Implications for Patient Counseling.

OBJECTIVE: Nearly all radiated vestibular schwannomas (VS) have solid tissue remaining at the radiation bed. The viability and proliferation capacity of this tissue has never been objectively assessed. The goals of our study were to (1) determine whether this tissue retains the morphological and immunohistochemical features of VS and (2) evaluate whether the tissue is capable of proliferation in cell culture. METHODS: Case history, magnetic resonance imaging (MRI), cell culture, histology, and immunohistochemistry. RESULTS: We report the first case of a post-radiated, sporadic VS patient whose non-growing, residual MR-enhancing solid tissue was examined histologically and in cell culture. These cells were architecturally identical to non-radiated VS, had a Ki67 proliferative index similar to non-radiated sporadic and NF2-associated VS, were S100 positive, and grew in culture with kinetics comparable to non-radiated VS. CONCLUSION: The long-term risk for delayed tumor growth and/or secondary malignancy in radiated VS patients is unknown. Because the average life span in the United States is nearly 80 years, patients should be informed that (1) residual VS cells are viable even when tumors appear to be non-growing on MRI, (2) post-radiation surveillance imaging is required indefinitely, and (3) radiation may incur more risk in those patients with life expectancy>20-25 years.

Feasibility of tomotherapy for postoperative irradiation of lower extremity sarcomas.

AIMS AND BACKGROUND: To evaluate the effectiveness of helical tomotherapy-based image-guided radiotherapy (IGRT) following surgery for lower extremity sarcoma. METHODS AND STUDY DESIGN: A retrospective review of three patients undergoing postoperative irradiation with tomotherapy for lower extremity sarcoma was conducted. Planning target volume (PTV) coverage, acute side effects, long-term complications and functional results were assessed. RESULTS: Tomotherapy allows adequate coverage of the PTV without an excessive radiation dose to the normal adjacent structures. Radiotherapy side effects were acceptable with no treatment breaks. All patients were disease free with no complications and no impairment of their daily activity at the last follow-up. CONCLUSION: IGRT delivered by tomotherapy may be ideally suited for sarcoma of the extremities because of its ability to achieve a high radiation dose along with excellent normal tissue sparing. Further prospective studies should be conducted to confirm this hypothesis.

Six-minute magnetic resonance imaging protocol for evaluation of acute ischemic stroke: pushing the boundaries.

BACKGROUND AND PURPOSE: If magnetic resonance imaging (MRI) is to compete with computed tomography for evaluation of patients with acute ischemic stroke, there is a need for further improvements in acquisition speed. METHODS: Inclusion criteria for this prospective, single institutional study were symptoms of acute ischemic stroke within 24 hours onset, National Institutes of Health Stroke Scale ≥3, and absence of MRI contraindications. A combination of echo-planar imaging (EPI) and a parallel acquisition technique were used on a 3T magnetic resonance (MR) scanner to accelerate the acquisition time. Image analysis was performed independently by 2 neuroradiologists. RESULTS: A total of 62 patients met inclusion criteria. A repeat MRI scan was performed in 22 patients resulting in a total of 84 MRIs available for analysis. Diagnostic image quality was achieved in 100% of diffusion-weighted imaging, 100% EPI-fluid attenuation inversion recovery imaging, 98% EPI-gradient recalled echo, 90% neck MR angiography and 96% of brain MR angiography, and 94% of dynamic susceptibility contrast perfusion scans with interobserver agreements (k) ranging from 0.64 to 0.84. Fifty-nine patients (95%) had acute infarction. There was good interobserver agreement for EPI-fluid attenuation inversion recovery imaging findings (k=0.78; 95% confidence interval, 0.66-0.87) and for detection of mismatch classification using dynamic susceptibility contrast-Tmax (k=0.92; 95% confidence interval, 0.87-0.94). Thirteen acute intracranial hemorrhages were detected on EPI-gradient recalled echo by both observers. A total of 68 and 72 segmental arterial stenoses were detected on contrast-enhanced MR angiography of the neck and brain with k=0.93, 95% confidence interval, 0.84 to 0.96 and 0.87, 95% confidence interval, 0.80 to 0.90, respectively. CONCLUSIONS: A 6-minute multimodal MR protocol with good diagnostic quality is feasible for the evaluation of patients with acute ischemic stroke and can result in significant reduction in scan time rivaling that of the multimodal computed tomographic protocol.

The potential role of magnetic resonance spectroscopy in image-guided radiotherapy.

Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues. The ability of MRS to diagnose areas of high metabolic activity linked to tumor cell proliferation is particularly useful for radiotherapy treatment planning because of better gross tumor volume (GTV) delineation. The GTV may be targeted with higher radiation dose, potentially improving local control without excessive irradiation to the normal adjacent tissues. Prostate cancer and glioblastoma multiforme (GBM) are two tumor models that are associated with a heterogeneous tumor distribution. Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe. Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

Potential applications of imaging and image-guided radiotherapy for brain metastases and glioblastoma to improve patient quality of life.

Treatment of glioblastoma multiforme (GBM) and brain metastasis remains a challenge because of the poor survival and the potential for brain damage following radiation. Despite concurrent chemotherapy and radiation dose escalation, local recurrence remains the predominant pattern of failure in GBM most likely secondary to repopulation of cancer stem cells. Even though radiotherapy is highly effective for local control of radio-resistant tumors such as melanoma and renal cell cancer, systemic disease progression is the cause of death in most patients with brain metastasis. Preservation of quality of life (QOL) of cancer survivors is the main issue for patients with brain metastasis. Image-guided radiotherapy (IGRT) by virtue of precise radiation dose delivery may reduce treatment time of patients with GBM without excessive toxicity and potentially improve neurocognitive function with preservation of local control in patients with brain metastasis. Future prospective trials for primary brain tumors or brain metastasis should include IGRT to assess its efficacy to improve patient QOL.

Osteoblastoma of the lateral skull base: work-up, surgical management, and a review of the literature".

Objectives To describe the work-up and surgical management of an osteoblastoma involving the lateral skull base. Typically occurring in the spine or long bones, osteoblastomas of the craniofacial skeleton are exceedingly rare and infrequently reported. A review of the current literature regarding temporal bone osteoblastoma, diagnosis, and treatment is described. Methods This case report describes the clinical presentation, radiographic studies, surgical management, histology, and postoperative follow-up of a young man presenting to a tertiary care neurotology practice with osteoblastoma involving the lateral skull base. A review of the current literature regarding osteoblastoma of the skull base, work-up, and treatment is described. Results A 15-year-old adolescent boy with a greater than 1-year history of right-sided retroauricular pain, a palpable postauricular mass, and chronic headaches presented for evaluation/management. Microscope examination of the ears, hearing, and cranial nerve function were normal. High-resolution temporal bone computed tomography and magnetic resonance imaging scans were obtained, which revealed an expansile mass involving the junction of the temporal and occipital bones. The patient underwent a combined retrosigmoid/retrolabyrinthine resection of this extradural tumor. Histology revealed a benign bone neoplasm consistent with osteoblastoma. Complete surgical resection was achieved, and the patient's symptoms fully resolved. Follow-up imaging studies found no evidence of recurrence. The scientific literature relevant to work-up and management of osteoblastoma is reviewed. Discussion Osteoblastomas of the lateral skull base are rare, histologically benign tumors that can present with radiographic features suggestive of malignancy. An en bloc resection is important for both diagnosis and definitive treatment of these neoplasms. The differential diagnosis on imaging and histology is discussed.

Feasibility of image-guided radiotherapy for elderly patients with locally advanced rectal cancer.

PURPOSE: The study aims to assess the tolerance of elderly patients (70 years or older) with locally advanced rectal cancers to image-guided radiotherapy (IGRT). A retrospective review of 13 elderly patients with locally advanced rectal cancer who underwent preoperative chemoradiation using IGRT was performed. Grade 3-4 acute toxicities, survival, and long-term complications were compared to 17 younger patients (<70 years) with the same disease stage. RESULTS: Grade 3-4 hematologic toxicities occurred in 7.6% and 0% (p = 0.4) and gastrointestinal toxicities, and, in 15.2% and 5% (p = 0.5), of elderly and younger patients, respectively. Surgery was aborted in three patients, two in the elderly group and one in the younger group. One patient in the elderly group died after surgery from cardiac arrhythmia. After a median follow-up of 34 months, five patients had died, two in the elderly and three in the younger group. The 3-year survival was 90.9% and 87.5% (p = 0.7) for the elderly and younger group respectively. Two patients in the younger group developed ischemic colitis and fecal incontinence. There was no statistically significant difference in acute and late toxicities as well as survival between the two groups. CONCLUSIONS AND CLINICAL RELEVANCE: Elderly patients with locally advanced rectal cancers may tolerate preoperative chemoradiation with IGRT as well as younger patients. Further prospective studies should be performed to investigate the potential of IGRT for possible cure in elderly patients with locally advanced rectal cancer.

Image-guided radiotherapy for locally advanced head and neck cancer.

Treatment of locally advanced head and neck cancer remains a challenge because of the head and neck complex anatomy and the tumor invasion to the adjacent organs and/or metastases to the cervical nodes. Postoperative irradiation or concurrent chemoradiation may lead to damage of radiosensitive structures such as the salivary glands, mandible, cochlea, larynx, and pharyngeal muscles. Xerostomia, osteoradionecrosis, deafness, hoarseness of the voice, dysphagia, and aspiration remain serious complications of head and neck irradiation and impair patient quality of life. Intensity-modulated and image-guided radiotherapy by virtue of steep dose gradient and daily imaging may allow for decreased radiation of the organs at risk for complication while preserving loco-regional control.

Acute stroke imaging: what clinicians need to know.

Advances in technology and software applications have contributed to new imaging modalities and strategies in the evaluation of patients with suspected acute cerebral infarction. Routine computed tomography (CT) and magnetic resonance imaging (MRI) have been the standard studies in stroke imaging, which have been complemented by CT and MR angiography, diffusion-weighted MR imaging, and cerebral perfusion studies, while conventional angiography is typically reserved for intra-arterial therapy. The purpose of this article is to review the variety of imaging studies available in the acute stroke setting, and to discuss the utility of each and the pertinent associated main findings. The appropriateness of which study and when each should be ordered is also discussed. At the conclusion of this article, the reader should have a more clear understanding of the neuroimaging modalities available for acute stroke imaging.

Assessing first year radiology resident competence pre-call: development and implementation of a computer-based exam before and after the 12 month training requirement.

RATIONALE AND OBJECTIVES: Whether first-year radiology residents are ready to start call after 6 or 12 months has been a subject of much debate. The purpose of this study was to establish an assessment that would evaluate the call readiness of first-year radiology residents and identify any individual areas of weakness using a comprehensive computerized format. Secondarily, we evaluated for any significant differences in performance before and after the change in precall training requirement from 6 to 12 months. MATERIALS AND METHODS: A list of >140 potential emergency radiology cases was given to first-year radiology residents at the beginning of the academic year. Over 4 years, three separate versions of a computerized examination were constructed using hyperlinked PowerPoint presentations and given to both first-year and second-year residents. No resident took the same version of the exam twice. Exam score and number of cases failed were assessed. Individual areas of weakness were identified and remediated with the residents. Statistical analysis was used to evaluate exam score and the number of cases failed, considering resident year and the three versions of the exam. RESULTS: Over 4 years, 17 of 19 (89%) first-year radiology residents passed the exam on first attempt. The two who failed were remediated and passed a different version of the exam 6 weeks later. Using the oral board scoring system, first-year radiology residents scored an average of 70.7 with 13 cases failed, compared to 71.1 with eight cases failed for second-year residents who scored statistically significantly higher. No significant difference was found in first-year radiology resident scoring before and after the 12-month training requirement prior to call. CONCLUSIONS: An emergency radiology examination was established to aid in the assessment of first-year radiology residents' competency prior to starting call, which has become a permanent part of the first-year curriculum. Over 4 years, all first-year residents were ultimately judged ready to start call. Of the variables assessed, only resident year showed a significant difference in scoring parameters. In particular, length of training prior to taking call showed no significant difference. Areas of weakness were identified for further study.