Preliminary Computed Tomography Radiomics Model for Predicting Pretreatment CD8+ T-Cell Infiltration Status for Primary Head and Neck Squamous Cell Carcinoma.

PURPOSE: Immunotherapy has emerged as a treatment option for head and neck squamous cell carcinoma (HNSCC), with tumor response being linked to the CD8+ T-cell inflammation. The purpose of this study is to assess whether computed tomography (CT) radiomic analysis can predict CD8+ T-cell enrichment in HNSCC primary tumors. METHODS: This retrospective study included 71 patients from a head and neck cancer genomics cohort with CD8+ T-cell enrichment status. Pretreatment contrast-enhanced neck CT scans were retrospectively reviewed using 3D Slicer for primary lesion segmentation.The SlicerRadiomics extension was used to extract 107 radiomic features. Ridge regression and lasso regression were applied for feature selection and model construction. RESULTS: Lasso regression defined Coarseness as the most important variable, followed by SmallDependenceEmphasis, SmallAreaLowGrayLevelEmphasis, Contrast.1, and Correlation.Ridge regression defined Coarseness as the most important variable, followed by SmallDependenceLowGrayLevelEmphasis, Contrast.1, DependenceNonUniformityNormalized, and Idmn. These variables identified by lasso and ridge regressions were used to create a combined logistic regression model. The area under the curve (AUC) for the lasso-generated model was 0.786 (95% confidence interval [CI], 0.532-1.000), and the AUC for the ridge-generated model was 0.786 (95% CI, 0.544-1.000). Combining the radiomic variables identified by lasso and ridge regressions with clinical characteristics including alcohol use, tobacco use, anatomic site, and initial T stage produced a model with an AUC of 0.898 (95% CI, 0.731-1.000). CONCLUSIONS: T-cell inflammation status of HNSCC primary tumors can be predicted using radiomic analysis of CT imaging and thereby help identify patients who would respond well to immunotherapy.

Differential Change in Size of Human Papillomavirus-Positive Cystic Versus Solid Squamous Cell Carcinoma Lymph Node Metastases in Response to Induction Chemotherapy.

PURPOSE: According to certain cancer treatment protocols, the response to induction chemotherapy of lymph node metastases based on radiographic measurements guides further management. The aim of this study is to verify the observation that cystic metastatic lymph nodes tend not to shrink as rapidly as solid metastatic lymph nodes in response to induction chemotherapy in patients with human papillomavirus-related oropharyngeal squamous cell carcinoma. METHODS: The lymphadenopathy in a cohort of patients from a clinical trial with human papillomavirus-related oropharyngeal squamous cell carcinoma with both baseline and postinduction chemotherapy (carboplatin/paclitaxel/cetuximab) contrast-enhanced neck computed tomography was retrospectively reviewed. The appearance of the metastatic lymph nodes on computed tomography was characterized as cystic or solid. A cystic lymph node was defined as having a hypoattenuating component greater than 20% of the total volume. The rates of short-axis and volume changes of cystic and solid lymph nodes were compared using 1-tailed t test. RESULTS: A total of 46 patients were included in this study, comprising 39 solid and 45 cystic lymph nodes. The rate of short-axis decrease was significantly greater for solid (1.33% per day) than cystic (1.08% per day) lymph nodes (P = 0.036). Likewise, the rate of volume decrease was significantly greater for solid (2.13% per day) than cystic (1.87% per day) lymph nodes (P = 0.014). CONCLUSIONS: This study suggests that in patients with human papillomavirus-related oropharyngeal squamous cell carcinoma solid lymph node metastases generally decrease in size at a greater rate than cystic lymph nodes after induction chemotherapy.

Magnetic Resonance Imaging Findings of Crystalloid-Containing Parotid Cysts.

Crystalloids are occasionally encountered on fine needle aspiration of cystic parotid lesions. This goal of this study was to retrospectively characterize the MRI features of a series benign crystalloid-containing parotid cysts. A total of 4 patients with fine needle aspiration findings of crystalloids and available parotid MRI scans were identified. Review of the imaging revealed that the cystic lesions contain layering material that corresponds to crystals.

Correlation of post-contrast T1-weighted MRI surface regularity, tumor bulk, and necrotic volume with Ki67 and p53 in glioblastomas.

PURPOSE: p53 and Ki67 status can be relevant to the management of glioblastoma. The goal of this study is to determine whether tumor morphology and bulk depicted on MRI correlate with p53 and Ki67 in glioblastoma. METHODS: A retrospective review of 223 patients with glioblastoma and corresponding p53 or Ki67 status, along with T1-weighted post-contrast MR images was performed. Enhancing tumors were outlined for determining surface regularity, tumor bulk, and necrotic volume. The median value of 0.1 was chosen for p53 and 0.2 for Ki67 to separate each data set into two classes. T tests and receiver operating characteristic analysis were performed to determine the separation of the classes and the predicting power of each feature. RESULTS: There were significant differences between tumor surface regularity (p = 0.01) and necrotic volume (p = 0.0429) according to Ki67 levels, although neither had statistically significant predictive power (AUC = 0.697, p = 0.0506 and AUC = 0.577, p = 0.164, respectively). There were also significant differences between tumor bulk (p = 0.0239) and necrotic volume (p = 0.0200) according to p53 levels, but again no significant predictive power was found using ROC analysis (AUC = 0.5882, p = 0.0894 and AUC = 0.567, p = 0.155, respectively). CONCLUSION: Quantitative morphological tumor characteristics on post-contrast T1-weighted MRI can to a certain degree provide insights regarding Ki67 and p53 status in patients with glioblastoma.

Case 250: Alpers-Huttenlocher Syndrome.

History A 10-year-old girl with global developmental delay and attention deficit hyperactivity disorder was transferred from an outside hospital because of confusion and multiple episodes of left face and arm jerking. Physical examination revealed normal muscle bulk, strength, and tone in the bilateral upper and lower extremities but insuppressible left arm and jaw twitching Lumbar puncture revealed no white or red blood cells, a normal glucose level of 55 mg/dL (3.0 mmol/L) (normal range, 50-80 mg/dL [2.8-4.4 mmol/L]), and an elevated protein level of 81.6 mg/dL (normal range, 15-60 mg/100 dL). A comprehensive metabolic panel revealed lactic acidosis. The patient was initially started on levetiracetam, phenobarbital, phenytoin, and topiramate for status epilepticus. Hepatic dysfunction was not present at initial admission but developed 2 months later, with an alanine aminotransferase level of 90-406 U/L (1.5-6.8 µkat/L) (normal range, 8-37 U/L [0.13-0.62 µkat/L]) and aspartate aminotransferase in the range of 75-187 U/L (1.2-3.1 µkat/L) (normal range, 8-35 U/L [0.13-0.58 µkat/L]). Electroencephalography revealed right parietal and occipital spike-and-wave discharges, with bursts of up to 20 seconds, which were indicative of subclinical status epilepticus. The family history was remarkable for a sister with head lag, developmental delay, seizure disorder, and liver failure.

Comparison between whole-body and head and neck neurovascular coils for 3-T magnetic resonance proton resonance frequency shift thermography guidance in the head and neck region.

The purpose of this study is to compare the image quality of magnetic resonance (MR) treatment planning images and proton resonance frequency (PRF) shift thermography images and inform coil selection for MR-guided laser ablation of tumors in the head and neck region. Laser ablation was performed on an agar phantom and monitored via MR PRF shift thermography on a 3-T scanner, following acquisition of T1-weighted (T1W) planning images. PRF shift thermography images and T2-weighted (T2W) planning images were also performed in the neck region of five normal human volunteers. Signal-to-noise ratios (SNR) and temperature uncertainty were calculated and compared between scans acquired with the quadrature mode body integrated coil and a head and neck neurovascular coil. T1W planning images of the agar phantom produced SNRs of 4.0 and 12.2 for the quadrature mode body integrated coil and head and neck neurovascular coil, respectively. The SNR of the phantom MR thermography magnitude images obtained using the quadrature mode body integrated coil was 14.4 versus 59.6 using the head and neck coil. The average temperature uncertainty for MR thermography performed on the phantom with the quadrature mode body integrated coil was 1.1 versus 0.3 °C with the head and neck coil. T2W planning images of the neck in five human volunteers produced SNRs of 28.3 and 91.0 for the quadrature mode body integrated coil and head and neck coil, respectively. MR thermography magnitude images of the neck in the volunteers obtained using the quadrature mode body integrated coil had a signal-to-noise ratio of 8.3, while the SNR using the head and neck coil was 16.1. The average temperature uncertainty for MR thermography performed on the volunteers with the body coil was 2.5 versus 1.6 °C with the head and neck neurovascular coil. The quadrature mode body integrated coil provides inferior image quality for both basic treatment planning sequences and MR PRF shift thermography compared with a neurovascular coil, but may nevertheless be adequate for clinical purposes.

CT Imaging Findings after Craniosynostosis Reconstructive Surgery.

Several surgical options are available for treating the different types of craniosynostosis, including fronto-orbital advancement and remodeling, total or subtotal cranial vault remodeling, barrel stave osteotomy with cranial remodeling, endoscopic suturectomy, monobloc advancement and cranioplasty, and revision cranioplasty. High-resolution, low-dose CT with 3D reconstructed images and volumetric analysis can be useful for evaluating the craniofacial skeleton following surgery. The various types of craniosynostosis surgery and corresponding imaging findings are reviewed in this article.

Clinical applications of dual-energy CT in head and neck imaging.

Dual-energy CT provides insights into the material properties of the tissues and can differentiate between tissues that have similar attenuation on conventional, single energy CT imaging. It has several useful and promising applications in head and neck imaging that an otolaryngologist could use to deliver improved clinical care. These applications include metal artifact reduction, atherosclerotic plaque and tumor characterization, detection of parathyroid lesions, and delineation of paranasal sinus ventilation. Dual-energy CT can potentially improve image quality, reduce radiation dose, and provide specific diagnostic information for certain head and neck lesions. This article reviews some current and potential otolaryngology applications of dual-energy CT.

Case 217: sinonasal organized hematoma.

HISTORY: A 15-year-old boy presented to the emergency department with intractable epistaxis. He had a prior history of epistaxis typically lasting 5-10 minutes and consisting of up to four episodes per year for several years. Otherwise, the patient had no relevant medical history, and he denied having prior trauma, surgery, bleeding diathesis, fever, chills, or vision changes. Likewise, the patient had no relevant family history. The patient's coagulation panel was unremarkable and included a prothrombin time of 15.4 seconds, an international normalized ratio of 1.2, and a partial thromboplastin time of 29.3 seconds. A thin-section unenhanced sinus computed tomography (CT) examination was performed. In addition, magnetic resonance (MR) imaging of the sinuses without and with intravenous contrast material was performed. The epistaxis was treated with nasal packing, which prevented further bleeding. Biopsy of the lesion was subsequently performed.

Advances in computed tomography imaging technology.

Computed tomography (CT) is an essential tool in diagnostic imaging for evaluating many clinical conditions. In recent years, there have been several notable advances in CT technology that already have had or are expected to have a significant clinical impact, including extreme multidetector CT, iterative reconstruction algorithms, dual-energy CT, cone-beam CT, portable CT, and phase-contrast CT. These techniques and their clinical applications are reviewed and illustrated in this article. In addition, emerging technologies that address deficiencies in these modalities are discussed.

Susceptibility-weighted imaging and diffusion-weighted imaging findings in central nervous system monomorphic B cell post-transplant lymphoproliferative disorder before and after treatment and comparison with primary B cell central nervous system lymphoma.

The purpose of this article is to review the MRI features of monomorphic central nervous system post-transplant lymphoproliferative disorder (CNS PTLD), including diffusion-weighted and susceptibility-weighted sequences before and after treatment and to compare the imaging findings with those of primary central nervous system B cell lymphoma (PCNS BCL). Retrospective review of the brain MRI characteristics in patients with pathology proven monomorphic CNS PTLD and PCNS BCL was performed. In particular, the enhancement, diffusion-weighted, susceptibility-weighted MRI characteristics of the lesions were evaluated. In addition, the diffusion-weighted, susceptibility-weighted MRI features after treatment for CNS PTLD were evaluated. A total of 12 lesions in six patients with CNS PTLD and 12 lesions in nine patients with PCNS BCL were identified on MRI. Among the CNS PTLD lesions with post-contrast images, 80 % demonstrated peripheral enhancement. All of the CNS PTLD lesions contained foci of intratumoral susceptibility signal (ITSS) and the average mean ADC values and ratios were 0.892 × 10(-3) mm(2)/s (standard deviation: 0.082 × 10(-3) mm(2)/s) and 1.19 (standard deviation: 0.15), respectively. On the other hand, 75 % of the PCNS BCL displayed diffuse enhancement, two cases (16.7 %) contained ITSS, and the mean ADC values and ratios were 0.721 × 10(-3) mm(2)/s (standard deviation: 0.093 × 10(-3) mm(2)/s), and 0.99 (standard deviation: 0.17), respectively. Thus, the presence of heterogeneous lesions with ITSS that do not necessarily have as extensive restricted diffusion as PCNS BCL is suggestive of CNS PTLD in the appropriate clinical setting. The preliminary data in this series suggests that diffusion-weighted imaging may serve as a useful biomarker for monitoring treatment response, in which successful treatment of CNS PTLD may result in increased ADC values. In addition, foci of susceptibility effect in CNS PTLD tend to persist or increase over the course of treatment.

MRI Findings After Surgery for Chiari Malformation Type I.

OBJECTIVE: Surgery plays an important role in the management of Chiari I malformation. The purpose of this article is to review expected and unexpected MRI findings after the various types of surgery performed during the treatment of Chiari I malformation and associated abnormalities. CONCLUSION: Familiarity with optimal MRI techniques and findings is important when evaluating postoperative changes after treatment of Chiari I malformation.

Uremic leontiasis ossea.

Uremic leontiasis ossea is a rare manifestation of renal osteodystrophy clinically characterized by jaw enlargement, widening of the nares, flattening of the nasal bridge, and increased interdental spacing. Computed tomography (CT) findings are particular characteristic and include serpiginous tunneling within the maxillofacial bones and cortical bone resorption. Nuclear medicine scans are also useful for demonstrating hyperplasia of the parathyroid glands. Ultimately, the diagnosis of uremic leontiasis ossea can be made non-invasively through a combination of clinical parameters and imaging findings, as described in this article.

Stapediovestibular dislocation depicted on temporal bone computed tomography with 3D rendering.

Stapediovestibular dislocation is an unusual form of ossicular trauma. In this article, a case of medial stapediovestibular dislocation and pneumolabyrinth due to penetrating injury with a stick diagnosed on temporal bone CT is described. In particular, 3D CT renderings can aid in the evaluation of the displaced ossicles.

3 Tesla intraoperative MRI for brain tumor surgery.

Implementation of intraoperative magnetic resonance imaging (iMRI) has been shown to optimize the extent of resection and safety of brain tumor surgery. In addition, iMRI can help account for the phenomenon of brain shift and can help to detect complications earlier than routine postoperative imaging, which can potentially improve patient outcome. The higher signal-to-noise ratio offered by 3 Tesla (T) iMRI compared with lower field strength systems is particularly advantageous. The purpose of this article is to review the imaging protocols, imaging findings, and technical considerations related to 3T iMRI. To maximize efficiency, iMRI sequences can be tailored to particular types of tumors and procedures, including nonenhancing brain tumor surgery, enhancing brain tumor surgery, transsphenoidal pituitary tumor surgery, and laser ablation. Unique imaging findings on iMRI include the presence of surgically induced enhancement, which can be a potential confounder for residual enhancing tumor, and hyperacute hemorrhage, which tends to have intermediate signal on T1-weighted sequences and high signal on T2-weighted sequences due to the presence of oxyhemoglobin. MR compatibility and radiofrequency shielding pose particularly stringent technical constraints at 3T and influence the design and usage of the surgical suite with iMRI.

Imaging guidelines and findings of extracranial glioblastoma.

Extracranial manifestations of glioblastoma are uncommon and include a wide spectrum of entities, such as primary spinal cord glioblastoma, spinal leptomeningeal metastasis, seeding into the scalp following intracranial glioblastoma resection, direct extension of an intracranial glioblastoma though a craniotomy defect, dissemination via shunt catheter, and systemic metastasis, including lymphatic and hematogenous spread. Imaging plays an important role in the management of patients with extracranial glioblastomas and guidelines for the imaging evaluation of these lesions are reviewed. For example, MRI is the modality of choice for evaluating glioblastoma involving the scalp and spine. In particular, advanced imaging techniques such as MR spectroscopy, MR perfusion, diffusion-weighted imaging, and diffusion-tensor imaging can be useful for early detection and characterization of these lesions. CT and (18)FDG-PET are suitable modalities for evaluating systemic and CSF shunt-related metastases.

Correlation between progression free survival and dynamic susceptibility contrast MRI perfusion in WHO grade III glioma subtypes.

The purpose of this study was to determine whether dynamic susceptibility contrast MR perfusion relative cerebral blood volume (rCBV) correlates with prognosis of World Health Organization (WHO) grade III glial tumors and their different subtypes. Retrospective evaluation of pre-treatment tumor rCBV derived from dynamic susceptibility contrast MR perfusion was performed in 34 patients with histopathologically diagnosed WHO grade III glial tumors (anaplastic astrocytomas (n = 20), oligodendrogliomas (n = 4), and oligoastrocytomas (n = 10)). Progression free survival was correlated with rCBV using Spearman rank analysis. ROC curve analysis was performed to determine the operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time. For all grade III tumors (n = 34) the mean rCBV was 2.51 with a progression free survival of 705.5 days. The mean rCBV of anaplastic astrocytomas was 2.47 with progression free survival 495.2 days. In contrast, the mean rCBV for oligodendroglial tumors was 2.56 with a progression free survival of 1005.6 days. Although there was no significant correlation between rCBV and progression free survival among all types of grade III gliomas (P = 0.12), among anaplastic astrocytomas there was a significant correlation between pretreatment rCBV and progression free survival with correlation coefficient of -0.51 (P = 0.02). The operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time (446.5 days) was 2.86 with 78 % accuracy and there was a significant difference between the survival of patients with anaplastic astrocytomas in the dichotomized groups (P = 0.0009). Pre-treatment rCBV may serve as a prognostic imaging biomarker for anaplastic astrocytomas, but not grade III oligodendroglioma tumors.

Imaging features and surgical management of giant parathyroid adenoma with autoinfarction.

Autoinfarction of a parathyroid adenoma can have an atypical clinicoradiologic features that can mimic an inflammatory process or malignancy. In addition, the associated fibrosis makes surgical resection more challenging than for regular parathyroid adenomas. The implications of these findings are that while autoinfarction of parathyroid adenomas is a rare phenomenon, this entity should be considered when there are heterogeneous and cystic components on imaging in patients without hypercalcemia. Ultimately, histopathology is necessary for definitive diagnosis.