Reverse Encoding Distortion Correction for Clinical Head Echo-Planar Diffusion-Weighted MRI: Initial Experience.

OBJECTIVE: This study aimed to evaluate the feasibility of the recently commercialized reverse encoding distortion correction (RDC) method for echo-planar imaging (EPI) diffusion-weighted imaging (DWI) by applying clinical head MRI. METHODS: This study included 50 consecutive patients who underwent head MRI, including single-shot (SS) EPI DWI and RDC-EPI DWI. For evaluation of normal structures, qualitative scores for image distortion, Dice similarity coefficient (DSC) values, distortion ratios, and mean apparent diffusion coefficient (ADC) values were assessed in the pons, temporal lobe at the skull base, and frontal lobe at the level of the lateral ventricles in 30 patients. To evaluate pathologies, qualitative scores for image distortion were assessed for 25 intracranial and 21 extracranial pathologies identified in 32 patients. RESULTS: Qualitative scores for image distortion, DSC values, distortion ratios, and mean ADC values of the pons and temporal lobe were significantly different between SS-EPI DWI and RDC-EPI DWI, whereas those of the frontal lobe at the level of the lateral ventricles were not significantly different between the 2 DWIs. The qualitative scores for image distortion and mean ADC values of extracranial pathologies were significantly different between the DWIs, whereas those of intracranial pathologies were not significantly different. CONCLUSIONS: RDC-EPI DWI significantly reduced image distortion and showed higher mean ADC values of the brain parenchyma in the skull base and extracranial pathologies.

Ultrafast lumbar spine MRI protocol using deep learning-based reconstruction: diagnostic equivalence to a conventional protocol.

OBJECTIVE: To evaluate the diagnostic equivalency between an ultrafast (1 min 53 s) lumbar MRI protocol using deep learning-based reconstruction and a conventional lumbar MRI protocol (12 min 31 s). MATERIALS AND METHODS: This study included 58 patients who underwent lumbar MRI using both conventional and ultrafast protocols, including sagittal T1-weighted, T2-weighted, short-TI inversion recovery, and axial T2-weighted sequences. Compared with the conventional protocol, the ultrafast protocol shortened the acquisition time to approximately one-sixth. To compensate for the decreased signal-to-noise ratio caused by the acceleration, deep learning-based reconstruction was applied. Three neuroradiologists graded degenerative changes and analyzed for presence of other pathologies. For the grading of degenerative changes, interprotocol intrareader agreement was assessed using kappa statics. Interchangeability between the two protocols was also tested by calculating the individual equivalence index between the intraprotocol interreader agreement and interprotocol interreader agreement. For the detection of other pathologies, interprotocol intrareader agreement was assessed. RESULTS: For the grading of degenerative changes, the kappa values for interprotocol intrareader agreement of all three readers ranged from 0.707 to 0.804, indicating substantial to almost perfect agreement. Except for foraminal stenosis and disc contour on axial images, the 95% confidence interval of the individual equivalence index was < 5%, indicating the two protocols were interchangeable. For the detection of other pathologies, the interprotocol intrareader agreement rates were > 98% for each individual pathology. CONCLUSIONS: Our proposed ultrafast lumbar spine MRI protocol provided almost equivalent diagnostic results to that of the conventional protocol, except for some degenerative changes.

Spontaneous closure of non-cavernous sinus dural arteriovenous fistulas: A case series and systematic review of the literature.

BACKGROUND AND PURPOSE: To report 9 new cases of non-cavernous sinus dural arteriovenous fistulas (NCS-DAVFs) that closed spontaneously and systematically review reports of other cases in the literature. MATERIAL AND METHODS: We performed a retrospective analysis of 9 cases from 2 institutions of NCS-DAVFs that closed spontaneously. Using PubMed and Scopus in accordance with the PRISMA guidelines, we systematically reviewed English language articles about NCS-DAVFs showing spontaneous closure. RESULTS: Review of the cases from 2 institutions identified 9 cases of NCS-DAVFs showing spontaneous closure in follow-up magnetic resonance angiography (MRA), and the systematic review of the literature yielded an additional 38 cases, which had been diagnosed by repeated arteriography. Collectively, the patients included 23 men and 24 women with a mean age of 54 years. The shunts were located in the transverse-sigmoid sinus in 24 cases (51%), anterior condylar confluence in 11, and other locations in 12. Based on the venous drainage pattern on arteriography, 27 cases (57%) were classified as low-risk NCS-DAVF (without cortical venous reflux) and 17 were classified as high-risk NCS-DAVF (with cortical venous reflux). Shunt closure was observed within 3 months in 17 cases (36%). Extrinsic predisposing factors for shunt closure were detected in 14 cases (30%). These included angiography in 7 cases, sinus recanalization in 4, development of sinus occlusion in 2, and sinus compression by a newly developed hematoma in 1. CONCLUSION: Spontaneous closures of NCS-DAVFs can occur for both high- and low-risk types. One-third of these closures occur within 3 months.

Superselective intra-arterial chemotherapy with concurrent radiotherapy for advanced parotid squamous cell carcinoma: a case report.

A case of advanced parotid cancer in which long-term control was achieved by superselective intra-arterial cisplatin infusion with concomitant radiotherapy is reported. A 63-year-old woman with parotid squamous cell carcinoma was referred to our hospital. Magnetic resonance images revealed extraparotid extension of the tumor, indicating that complete resection would be difficult. Consequently, intra-arterial cisplatin infusion with concomitant radiotherapy was planned as an alternative therapy. Superselective intra-arterial infusion of cisplatin (100 mg/m(2)) was performed six times, at intervals of 7-9 days. The arteries chosen for superselective infusion were the posterior auricular artery, the transverse facial artery and the intrinsic parotid artery originating directly from the external carotid artery. Concurrently, external radiotherapy of a total of 50 Gy in 25 fractions was also performed. The patient achieved a complete response and has remained free of disease recurrence 5 years after treatment. Intra-arterial cisplatin infusion with concomitant radiotherapy can be a practical option for patients with unresectable parotid squamous cell carcinoma.

Calyceal Diverticulum Found Incidentally on 18 F-FDG PET/CT Imaging.

ABSTRACT: A 69-year-old man with pancreatic cancer underwent 18 F-FDG PET/CT examination for tumor staging. The PET images showed a focal mass-like FDG accumulation in the left kidney mimicking malignancy, whereas simultaneous CT and fused PET/CT images suggested a cystic lesion. On subsequent MR examination, the lesion appeared cystic on T2-weighted, contrast-enhanced arterial phase, and contrast-enhanced venous phase images. In addition, excretory phase images showed filling contrast medium to the cystic cavity, leading to a diagnosis of calyceal diverticulum. This report suggests that the possibility of a calyceal diverticulum should be considered in cases with focal FDG accumulation in renal cystic lesions.

Intravertebral pneumatocysts of the cervical spine.

INTRODUCTION: The aim of this study was to investigate the prevalence of intravertebral pneumatocyst (IVP) of the cervical spine by age group, compared with that of intradiscal vacuum (IDV). METHODS: We investigated 500 consecutive patients who underwent cervical computed tomography (CT) from May 2012 to May 2013 for various indications. CT datasets were assessed for the presence of IVPs and IDVs with stratification by age. RESULTS: IVPs of the cervical spine were detected in 8 % (7 of 86 subjects) of patients in their forties or below, 30 % (23 of 75) in their fifties, 49 % (67 of 136) in their sixties, 55 % (76 of 137) in their seventies, and 60 % (40 of 66) in their eighties or over. IDVs of the cervical spine were detected in 6, 25, 48, 54, and 57 %, respectively. Coexistence of both phenomena was identified in 4, 17, 33, 40, and 43 %, respectively. CONCLUSION: IVPs of the cervical spine are a common incidental finding, increasing in prevalence with age and more common than IDV in all age groups.

Conventional MRI findings for predicting submandibular pleomorphic adenoma.

BACKGROUND: Although pleomorphic adenomas account for over 90% of all benign submandibular gland tumors, the imaging features of submandibular pleomorphic adenomas have not been reported in a large number of cases. PURPOSE: To assess the conventional magnetic resonance imaging (MRI) findings for predicting the submandibular pleomorphic adenoma. MATERIAL AND METHODS: MR studies of 42 pleomorphic adenomas and 28 other types of tumor were reviewed. MR images were assessed for the presence of hyperintense areas on T2-weighted images (first sign), a well-defined margin (second sign), and presence of crescent-shaped compression of the ipsilateral normal submandibular gland (third sign). RESULTS: For identifying submandibular pleomorphic adenoma, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 97.6%, 50.0%, 74.5%, 93.3%, and 78.6% for the first sign, 95.2%, 46.4% 72.7%, 86.7%, and 75.7% for the second sign, and 23.8%, 100%, 86.7%, 46.7%, and 54.3% for the third sign, respectively. Combining the first and second findings achieved to 85.7% specificity and 90.9% accuracy. CONCLUSION: Although non-specific, submandibular pleomorphic adenomas usually have hyperintense areas on T2-weighted images and well-defined margins. In addition, crescent-shaped compression of the ipsilateral normal gland seems to represent a highly specific sign.

High 18F-FDG Uptake in a Papillary Craniopharyngioma of the Third Ventricle.

ABSTRACT: Craniopharyngioma is a benign tumor classified as grade 1 by the World Health Organization Classification of Tumors of the Central Nervous System. We present a rare case of a high-18F-FDG-avidity papillary craniopharyngioma of the third ventricle. A 65-year-old man underwent CT and MRI examinations for gait disturbance, lower-limb weakness, and urinary incontinence, and an oval solid tumor that extended from the suprasellar region to the third ventricle was identified. 18F-FDG PET/CT showed high accumulation (SUVmax, 22.3) in the tumor. A transventricular endoscopic tumor biopsy led to the diagnosis of papillary craniopharyngioma.

Nonbrain metastases seen on magnetic resonance imaging during metastatic brain tumor screening.

Although metastases found during head magnetic resonance imaging (MRI) are not limited to metastatic brain tumors, the MRI is a very common method for "brain metastasis screening," a modality that is being increasingly performed. In this review, we describe MRI findings of nonbrain metastases and discuss ways to avoid missing these lesions. Metastatic cranial bone tumors are among the most common nonbrain metastatic lesions found on head MRI, followed by leptomeningeal carcinomatosis. The other less-frequent metastatic lesions include those in the ventricle/choroid plexus, the pituitary gland and stalk, and the pineal gland. Metastases in the head and neck area, as well as cranial and intracranial lesions, should be carefully evaluated. Furthermore, direct geographical invasion, perineural spread, and double cancers should also be considered. While it is important to recognize these metastatic lesions on MRI, because they may necessitate a change in treatment strategy that could lead to an improvement in prognosis due to early introduction of therapy, nonbrain lesions should also be given greater attention, given the increasing survival of patients with cancer and advances in MRI technology, such as contrast-enhanced-3D T1-weighted imaging.

Carcinoma ex pleomorphic adenoma of the parotid gland.

BACKGROUND: Carcinoma ex pleomorphic adenoma (CXPA) is a rare aggressive epithelial malignancy arising from a primary or recurrent benign mixed tumor. Only a few case reports describing the radiologic features of CXPA have been published. PURPOSE: To describe and characterize the magnetic resonance (MR) imaging findings of CXPA in the parotid gland and correlate them with pathologic findings. MATERIAL AND METHODS: The MR images of surgically proven CXPA in the parotid gland of five men and five women ranging in age from 28 to 75 years (mean 52 years) were retrospectively reviewed. All MR images were evaluated with emphasis on the size, margin characteristics, extraparotid infiltration, the presence of an encapsulated component, and signal intensity on T2-weighted or short-inversion-time inversion recovery (STIR) images. RESULTS: The average maximal diameter was 4.3 cm. All 10 tumors had ill-defined boundaries, and seven tumors showed extraparotid infiltration, reflecting invasive growth of the malignant component identified on histological examination. Eight tumors had a round encapsulated component and seven of those signal intensities were a mixture of hypo- and hyperintensity on T2-weighted or STIR images. Histological correlation of these components revealed fibrously encapsulated tumors containing hyalinization and myxoid tissue, suggesting degenerated pleomorphic adenoma. Invasive malignant components had non-specific and various signal intensities. CONCLUSION: An invasive parotid mass co-existing with a round encapsulated component is suggestive of carcinoma ex pleomorphic adenoma.

Quantitative evaluation of simultaneous spatial and temporal regularization in dynamic contrast-enhanced MRI of the liver using Gd-EOB-DTPA.

The purpose of this study was to quantitatively evaluate the usefulness of simultaneous spatial and temporal regularization using total variation (TV), total generalized variation (TGV), a combination of low-rank decomposition (LRD) and TV (LRD+TV), a combination of LRD and TGV (LRD+TGV), and nuclear norm (NN) when applied to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rats with concanavalin A (ConA)-induced acute hepatic injury. The rats were divided into three groups: normal control (NC) (n = 10), ConA10 (n = 8), and ConA20 (n = 7). Rats in the ConA10 and ConA20 groups were intravenously injected with 10 and 20 mg/kg of ConA, respectively; those in the NC group were intravenously injected with the same volume of saline. DCE-MRI studies were performed using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA; 0.025 mmol Gd/kg) as a contrast agent (CA), 24 h after the ConA or saline injection. After the DCE-MRI study, we generated zero-filled and undersampled k-space data from the original images using a pseudoradial sampling scheme with 4 to 64 spokes. We subsequently reconstructed images from these data using the above regularizers and calculated the signal-to-error ratio (SERimg) and structural similarity index measure (SSIM) using the original and reconstructed images. We also calculated the area under the curve (AUC), rate of CA washout (λw), maximum relative enhancement (REmax), and time to REmax (Tmax) from time-intensity curves using an empirical mathematical model (EMM) and the signal-to-error ratio for curve fitting (SERfit) from the original and fit curves. We also compared the parameters obtained using the pseudoradial and Cartesian sampling schemes in the NC group. When using LRD+TV and LRD+TGV, both SERimg and SSIM were greater than those for the other regularizers at all spoke numbers studied; the SERfit for TGV was the greatest. When using TGV and LRD+TGV, in the majority of cases the AUCs did not significantly differ from those obtained from the original images, whereas those for LRD+TV and NN were significantly less at several spoke numbers. The λw for NN was significantly greater at numerous spoke numbers in the NC group; the REmax values for LRD+TV and NN were significantly less at several spoke numbers in all groups. The Tmax values for TV, TGV, and LRD+TGV were significantly greater at numerous spoke numbers in the NC group. Although there were significant differences in SERimg and SSIM between the pseudoradial and Cartesian sampling schemes, the kinetic parameters obtained by the EMM did not significantly differ between the two sampling schemes, with certain exceptions. In conclusion, our results suggest that simultaneous spatial and temporal regularization using TGV or LRD+TGV is useful for accelerating DCE-MRI without significant reduction in the accuracy of the kinetic parameter estimation, even at extremely low sampling factors.

Effect of urinary glucose concentration and pH on signal intensity in magnetic resonance images.

PURPOSE: With advances in anti-diabetes drugs, increasing numbers of patients have high urinary glucose concentrations, which may alter magnetic resonance (MR) signal intensity. We sought to elucidate the effect of urinary glucose concentration and pH on transverse relaxation and MR signal intensity. MATERIALS AND METHODS: The transverse relaxation rate (R2) was measured in samples with different glucose concentrations (in vitro) and in the urinary bladder of seven patients with diabetes and nine healthy volunteers (in vivo). The glucose concentration and pH in the in vitro samples and urine were measured. The signal intensity ratio of the bladder to adjacent tissues was obtained on T2-weighted imaging (WI), T1WI, and MR urography (in vivo). To clarify the effect of pH further, the urine of two healthy subjects was adjusted with acid and/or base to obtain various pH values (ex vivo). RESULTS: R2 increased significantly with high glucose concentrations in the in vitro study. In the in vivo study, high glucose concentration (p < 0.001) and low pH (p = 0.005) were significantly associated with high R2. R2 was higher (p = 0.002) and the signal in maximum-intensity projection images of MR urography was lower (p = 0.005) in patients with diabetes than in healthy subjects. Ex vivo study revealed that a decrease in pH in acid portion resulted in increased R2. CONCLUSION: High concentrations of urinary glucose and low pH both enhance transverse relaxation, which, in turn, causes low signal intensity in urinary bladder on long echo time (TE) images, such as MR urography. Radiologists should be aware of this phenomenon when interpreting abnormally low-intensity bladders on long TE images.

Ultrafast cervcial spine MRI protocol using deep learning-based reconstruction: Diagnostic equivalence to a conventional protocol.

PURPOSE: A major drawback of magnetic resonance imaging (MRI) is its limited imaging speed. This study proposed an ultrafast cervical spine MRI protocol (2 min 57 s) using deep learning-based reconstruction (DLR) and compared the diagnostic results to those of conventional MRI protocols (12 min 54 s). METHODS: Fifty patients who underwent cervical spine MRI using both conventional and ultrafast protocols, including sagittal T1-weighted, T2-weighted, short-TI inversion recovery, and axial T2*-weighted imaging were included in this study. The ultrafast protocol shortened the acquisition time to approximately-one-fourth of that of the conventional protocol by reducing the phase matrix, oversampling rate, and number of excitations, and by applying compressed sensing. To compensate for the decreased signal-to-noise ratio caused by acceleration, noise reduction using DLR was performed. For image interpretation, three neuroradiologists graded or classified degenerative changes, including central canal stenosis, foraminal stenosis, endplate degeneration, disc degeneration, and disc hernia. The presence of other pathologies was also recorded. Given the absence of a reference standard, we tested the interchangeability of the two protocols by calculating the 95% confidence interval (CI) of the individual equivalence index. We also assessed the inter-protocol intra-reader agreement using kappa statistics. RESULTS: Except for endplate degeneration, the 95 % CI of the individual equivalence index for all variables did not exceed 5 %, indicating interchangeability between the two protocols. The kappa values ranged from 0.600 to 0.977, indicating substantial to almost perfect agreement. CONCLUSIONS: The proposed ultrafast MRI protocol yielded almost equivalent diagnostic results compared as the conventional protocol.

Imaging of the nigrostriatal system for evaluating the preclinical phase of Parkinson's disease development: the utility of neuromelanin, diffusion MRI, and DAT-SPECT.

OBJECTIVE: To assess the utility of examining the nigrostriatal system with MRI and dopamine transporter (DAT) imaging for evaluating the preclinical phase of Parkinson's disease (PD). METHODS: The subjects were 32 patients with early PD and a history of probable rapid eye movement sleep behavior disorder (RBD; PD group), 15 patients with idiopathic RBD (RBD group), and 24 age-matched healthy controls (HC group) who underwent neuromelanin and diffusion tensor MRI for analysis of the substantia nigra pars compacta (SNpc). The RBD and PD groups underwent DAT imaging. In the RBD group, totals of 39 MRI and 27 DAT imaging examinations were obtained longitudinally. For each value, intergroup differences and receiver operating characteristic analysis for diagnostic performance were examined statistically. RESULTS: The neuromelanin value was significantly lower and the diffusion tensor values except fractional anisotropy were significantly higher in the RBD and PD groups than in the HC group. The DAT specific binding ratio (SBR) was significantly lower in the PD group than in the RBD group. The areas under the receiver operating characteristic curves (AUCs) for neuromelanin/mean diffusivity value in the SNpc were 0.76/0.82 for diagnosing RBD and 0.83/0.80 for diagnosing PD. The area under the receiver operating characteristic curves for the SBR for discriminating PD from RBD was 0.87. CONCLUSION: MRI and DAT imaging may be useful for evaluating sequential nigrostriatal changes during the preclinical phase of PD. ADVANCES IN KNOWLEDGE: MRI detects nigrostriatal changes in both RBD and early PD, and DAT imaging detects nigrostriatal changes during the transition to PD in RBD.

Ascending pharyngeal-vertebral anastomosis demonstrated by computed tomography angiography of the ascending pharyngeal artery: a case report.

Ascending pharyngeal-vertebral anastomosis has been identified by angiography of the carotid artery in several cases. We present a case of ascending pharyngeal-vertebral anastomosis that was found incidentally in computed tomography angiography of the ascending pharyngeal artery. Images revealed that the anastomosis formed through the hypoglossal branch of the neuromeningeal trunk. The anastomosis seemed to be associated with hypoplasia of the right vertebral artery. Interventional radiologists should be aware of this dangerous anastomotic route of the APA to the VA. Discovery of hypoplasia of the major intracranial arteries before intra-arterial chemotherapy or embolization in head and neck area may avoid subsequent complications.

Applicability of deep learning-based reconstruction trained by brain and knee 3T MRI to lumbar 1.5T MRI.

BACKGROUND: Several deep learning-based methods have been proposed for addressing the long scanning time of magnetic resonance imaging. Most are trained using brain 3T magnetic resonance images, but is unclear whether performance is affected when applying these methods to different anatomical sites and at different field strengths. PURPOSE: To validate the denoising performance of deep learning-based reconstruction method trained by brain and knee 3T magnetic resonance images when applied to lumbar 1.5T magnetic resonance images. MATERIAL AND METHODS: Using a 1.5T scanner, we obtained lumber T2-weighted sequences in 10 volunteers using three different scanning times: 228 s (standard), 119 s (double-fast), and 68 s (triple-fast). We compared the images obtained by the standard sequence with those obtained by the deep learning-based reconstruction-applied faster sequences. RESULTS: Signal-to-noise ratio values were significantly higher for deep learning-based reconstruction-double-fast than for standard and did not differ significantly between deep learning-based reconstruction-triple-fast and standard. Contrast-to-noise ratio values also did not differ significantly between deep learning-based reconstruction-triple-fast and standard. Qualitative scores for perceived signal-to-noise ratio and overall image quality were significantly higher for deep learning-based reconstruction-double fast and deep learning-based reconstruction-triple-fast than for standard. Average scores for sharpness, contrast, and structure visibility were equal to or higher for deep learning-based reconstruction-double-fast and deep learning-based reconstruction-triple-fast than for standard, but the differences were not statistically significant. The average scores for artifact were lower for deep learning-based reconstruction-double-fast and deep learning-based reconstruction-triple-fast than for standard, but the differences were not statistically significant. CONCLUSION: The deep learning-based reconstruction method trained by 3T brain and knee images may reduce the scanning time of 1.5T lumbar magnetic resonance images by one-third without sacrificing image quality.

Improved visualization of the chorda tympani nerve using ultra-high-resolution computed tomography.

BACKGROUND: Recognition of the anatomical course of the chorda tympani nerve (CTN) is important for preventing iatrogenic injuries during middle-ear surgery. PURPOSE: This study aims to compare visualization of the CTN using two computed tomography (CT) methods: conventional high-resolution CT (C-HRCT) and ultra-high-resolution CT (U-HRCT). MATERIALS AND METHODS: We performed a retrospective visual assessment of 59 CTNs in normal temporal bones of 54 consecutive patients who underwent both C-HRCT and U-HRCT. After dividing CTN into three anatomical segments (posterior canaliculus, tympanic segment, and anterior canaliculus), two neuroradiologists scored the visualizations on a four-point scale. RESULTS: On C-HRCT, the visual scores of the posterior canaliculus, tympanic segment, and anterior canaliculus were 3.5 ± 0.7, 1.6 ± 0.6, and 3.1 ± 0.7, respectively. The respective values were significantly higher in all segments on U-HRCT: 3.9 ± 0.2, 2.4 ± 0.6, 3.5 ± 0.6 (p < 0.01). Although the difference in scores between methods was greatest for the tympanic segment, the visual score on U-HRCT was lower for the tympanic segment than for the anterior and posterior segments (p < 0.01). CONCLUSION: Ultra-high-resolution CT provides superior visualization of the CTN, especially the tympanic segment.

MRI imaging features of HIV-related central nervous system diseases: diagnosis by pattern recognition in daily practice.

With the advent of antiretroviral therapy (ART), the prognosis of people infected with human immunodeficiency virus (HIV) has improved, and the frequency of HIV-related central nervous system (CNS) diseases has decreased. Nevertheless, mortality from HIV-related CNS diseases, including those associated with ART (e.g., immune reconstitution inflammatory syndrome) remains significant. Magnetic resonance imaging (MRI) can improve the outlook for people with HIV through early diagnosis and prompt treatment. For example, HIV encephalopathy shows a diffuse bilateral pattern, whereas progressive multifocal leukoencephalopathy, HIV-related primary CNS lymphoma, and CNS toxoplasmosis show focal patterns on MRI. Among the other diseases caused by opportunistic infections, CNS cryptococcosis and CNS tuberculosis have extremely poor prognoses unless diagnosed early. Immune reconstitution inflammatory syndrome shows distinct MRI findings from the offending opportunistic infections. Although distinguishing between HIV-related CNS diseases based on imaging alone is difficult, in this review, we discuss how pattern recognition approaches can contribute to their early differentiation.

Detectability of pulmonary ossifications in fibrotic lung on ultra-high-resolution CT using 2048 matrix size and 0.25-mm slice thickness.

To investigate the prevalence of nodular pulmonary ossifications (POs) in patients with honeycombing on ultra-high-resolution CT (UHRCT) and to compare the detectability of nodular POs between images reconstructed using the ultra-high-resolution setting (UHR-setting) and those using the conventional setting (C-setting) on UHRCT. Twenty patients with honeycombing in the lung were evaluated retrospectively. All patients underwent non-contrast-enhanced UHRCT. Images were reconstructed with UHR-setting (matrix, 2048 × 2048; slice thickness, 0.25 mm) and with C-setting (matrix size, 512 × 512; slice thickness, 0.5 mm). Two chest radiologists independently recorded the number of nodular POs (< 4 mm diameter) in each lung lobes. Each lobe was classified as one of the following five categories according to the number of POs: C0, none; C1, 1-4 POs; C2, 5-9 POs; C3, 10-49 POs; and C4, ≥ 50 POs. The maximum CT values of the POs were measured and compared between the two settings. PO categories were significantly higher with UHR-setting than with C-setting (p < 0.001). Maximum CT values were significantly higher with UHR-setting than with C-setting (p < 0.001). Nodular POs were seen in 80% or more of patients with honeycombing and more easily detected in images reconstructed with UHR-setting than in those with C-setting.

Prognostic factors for bone metastases from head and neck squamous cell carcinoma: A case series of 97 patients.

Although bone is the second-most frequent site of distant metastases of head and neck squamous cell carcinoma (HNSCC), variable prognostic factors in patients with bone metastases from HNSCC have not been fully investigated. The aim of the present study was to assess the prognostic factors affecting overall survival (OS) in these patients. The medical records of 97 patients at two institutions who developed bone metastases from HNSCC between January 2010 and December 2020 were retrospectively reviewed. A multivariate analysis using a Cox proportional hazards model was performed to identify potential clinical predictive factors for longer OS. The median OS was 7 months, and the 1- and 2-year OS rates for all patients were 35.4 and 19.2%, respectively. The independent predictive factors for longer OS were single bone metastasis, good performance status and administration of systemic chemotherapy. The median OS with each predictor was 10, 10 and 10.5 months, respectively. In a selected group of patients with these three factors, the OS was 14.5 months. In conclusion, single bone metastasis, a good performance status and systemic chemotherapy were independent predictors of longer OS in patients with HNSCC, but their contributions were limited.