Regression of Necrotic Lesions after Methotrexate Withdrawal in Patients with Methotrexate-Associated Lymphoproliferative Disorders: A Retrospective CT Study.

This retrospective study investigated whether necrotic lesions detected on a computed tomography (CT) scan are more regressive than non-necrotic lesions after methotrexate withdrawal in patients pathologically diagnosed with methotrexate-associated lymphoproliferative disorders (MTX-LPD). In total, 89 lesions extracted from 24 patients on CT scans were included in the analysis. All patients had been evaluated for the presence of necrosis within lesions via CT scan upon first suspicion of MTX-LPD (baseline CT scan). The percentage lesion size reduction between the baseline and initial follow-up CT scan was calculated. The association between necrosis within lesions and size changes was estimated via linear regression analyses using both crude and adjusted models. Necrosis was significantly more common in extranodal lesions (27 out of 30 lesions, 90%) than in nodal lesions (9 out of 59 lesions, 15%, p<0.001). In the crude model, the regression of necrotic lesions was 58.5% greater than that of non-necrotic lesions; the difference was statistically significant (p<0.001). Additionally, the longest diameter of necrotic lesions at the baseline CT scan was significantly greater than that of non-necrotic lesions (p<0.001). Based on the adjusted model, necrotic lesions showed 49.3% greater regression than non-necrotic lesions (p=0.017). Necrosis detected on a CT scan was found to be an independent predictor of regression after MTX withdrawal in patients with MTX-LPD.

Evaluation of the ear ossicles with photon-counting detector CT.

Recently, computed tomography with photon-counting detector (PCD-CT) has been developed to enable high-resolution imaging at a lower radiation dose. PCD-CT employs a photon-counting detector that can measure the number of incident X-ray photons and their energy. The newly released PCD-CT (NAEOTOM Alpha, Siemens Healthineers, Forchheim, Germany) has been in clinical use at our institution since December 2022. The PCD-CT offers several advantages over current state-of-the-art energy-integrating detector CT (EID-CT). The PCD-CT does not require septa to create a detector channel, while EID-CT does. Therefore, downsizing the anode to achieve higher resolution does not affect the dose efficiency of the PCD-CT. CT is an indispensable modality for evaluating ear ossicles. The ear ossicles and joints are clearly depicted by PCD-CT. In particular, the anterior and posterior legs of the stapes, which are sometimes unclear on conventional CT scans, can be clearly visualized. We present cases of congenital anomalies of the ossicular chain, ossicular chain dislocation, tympanosclerosis, and cholesteatoma in which PCD-CT was useful. This short article reports the usefulness of PCD-CT in the 3D visualization of the ear ossicles.

A Case of Migration of a Hydrogel Spacer for Radiotherapy into the Pulmonary Artery.

A 67-year-old man was referred to our hospital for the diagnosis and treatment of prostate cancer. Multidisciplinary discussion led to intensity-modulated radiotherapy preceded by hormone therapy. Before radiotherapy, a biodegradable hydrogel spacer (HS) was placed between the prostate and rectum to reduce radiation injury risk. Three weeks postplacement, pelvic magnetic resonance imaging revealed HS migration into the pelvic vein. Subsequent whole-body contrast-enhanced computed tomography (CECT) revealed HS migration into the pulmonary artery. The patient showed no symptoms or clinical signs. Radiotherapy was completed uneventfully. Complete absorption of the migrated HS was confirmed using CECT images 5 months postplacement.

Endolymphatic Hydrops on Magnetic Resonance Imaging May Be an Independent Finding on Aging in Neurotologic Patients.

OBJECTIVE: To clarify whether age impacts the development of endolymphatic hydrops (ELH) in neurotologic patients. Documentation of ELH in living patients on magnetic resonance imaging (MRI) allows analysis of patient age and formation of ELH, which is impossible by means of postmortem temporal bone pathology. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Fifty patients (100 ears) with top 3 diagnoses of definite Menière's disease, delayed ELH, or probable Menière's disease. INTERVENTIONS: Endolymph MRI after intravenous gadolinium injection and pure-tone audiometry. MAIN OUTCOME MEASURES: Cochlear and vestibular ELH confirmed by MRI. RESULTS: The prevalences of ears showing both cochlear and vestibular ELH were similar among age groups <30 years (30%), 30-59 years (25.9%), and ≥60 years (34.4%; p > 0.05; χ2 test). Using logistic regression modeling, mean hearing level at the six frequencies was positively associated with a higher risk of cochlear ELH (odds ratio, 1.3; 95% confidence interval, 1.1-1.5 per 10-dB increment). In the same regression model, age did not impact the outcome of cochlear ELH (odds ratio, 1.0; 95%confidence interval, 0.7-1.4 per 10-year increment). Age did not differ among ears with no ELH (mean ± standard deviation age, 48.6 ± 14.4 yr), ears with only cochlear ELH (59.3 ± 10.7 yr), ears with only vestibular ELH (50.4 ± 16.9 yr), or ears with both cochlear and vestibular ELH (51.5 ± 18.4 yr; p > 0.05, analysis of variance). CONCLUSION: Chronological age was not associated with the formation of ELH. Aging per se may not be associated with the development of ELH in neurotologic patients.

15-year follow-up for steroid-responsive, fluctuating hearing loss in the ear with endolymphatic hydrops confirmed by magnetic resonance imaging.

Autoimmune mechanisms may play crucial roles in the etiology of endolymphatic hydrops (ELH), which was previously regarded as a postmortem finding in the temporal bone. Recently, ELH has been visualized using 3-T MR imaging in living patients. A 47-year-old woman with deafness in the left ear since adolescence developed right-sided steroid-responsive sensorineural hearing loss in the low frequencies. During over 15 years of follow-up at our otolaryngology clinic, acute deteriorations of hearing in the only hearing ear repeatedly recovered with administration of intravenous and oral steroids. Hearing in the only hearing ear at 62 years old was preserved and comparable to that at 47 years old. At 61 years old, cochlear ELH was documented bilaterally on MR imaging, appearing more severe in the deafened ear than in the hearing ear. This case provides new evidence of the potential steroid-responsiveness of hearing loss due to contralateral-type delayed ELH distinctly visualized on MR imaging.

Imaging evaluation of hereditary renal tumors: a pictorial review.

More than 10 hereditary renal tumor syndromes (HRTSs) and related germline mutations have been reported with HRTS-associated renal and extrarenal manifestations with benign and malignant tumors. Radiologists play an important role in detecting solitary or multiple renal masses with or without extrarenal findings on imaging and may raise the possibility of an inherited predisposition to renal cell carcinoma, providing direction for further screening, intervention and surveillance of the patients and their close family members before the development of potentially lethal renal and extrarenal tumors. Renal cell carcinomas (RCCs) associated with von Hippel-Lindau disease are typically slow growing while RCCs associated with HRTSs, such as hereditary leiomyomatosis and renal cell carcinoma syndrome, are highly aggressive. Therefore, radiologists need to be familiar with clinical and imaging findings of renal and extrarenal manifestations of HRTSs. This article reviews clinical and imaging findings for the evaluation of patients with well-established HRTSs from a radiologist's perspective to facilitate the clinical decision-making process for patient management.

Differentiation of Small (≤ 4 cm) Renal Masses on Multiphase Contrast-Enhanced CT by Deep Learning.

OBJECTIVE. This study evaluated the utility of a deep learning method for determining whether a small (≤ 4 cm) solid renal mass was benign or malignant on multiphase contrast-enhanced CT. MATERIALS AND METHODS. This retrospective study included 1807 image sets from 168 pathologically diagnosed small (≤ 4 cm) solid renal masses with four CT phases (unenhanced, corticomedullary, nephrogenic, and excretory) in 159 patients between 2012 and 2016. Masses were classified as malignant (n = 136) or benign (n = 32). The dataset was randomly divided into five subsets: four were used for augmentation and supervised training (48,832 images), and one was used for testing (281 images). The Inception-v3 architecture convolutional neural network (CNN) model was used. The AUC for malignancy and accuracy at optimal cutoff values of output data were evaluated in six different CNN models. Multivariate logistic regression analysis was also performed. RESULTS. Malignant and benign lesions showed no significant difference of size. The AUC value of corticomedullary phase was higher than that of other phases (corticomedullary vs excretory, p = 0.022). The highest accuracy (88%) was achieved in corticomedullary phase images. Multivariate analysis revealed that the CNN model of corticomedullary phase was a significant predictor for malignancy compared with other CNN models, age, sex, and lesion size. CONCLUSION. A deep learning method with a CNN allowed acceptable differentiation of small (≤ 4 cm) solid renal masses in dynamic CT images, especially in the corticomedullary image model.

A case of autoimmune pulmonary alveolar proteinosis appearing as a localized ground-glass opacity.

Pulmonary alveolar proteinosis (PAP) is a rare diffuse lung disease caused by abnormal intra-alveolar surfactant accumulation; it commonly appears as a "crazy-paving" pattern on high-resolution computed tomography. Here, we report a rare case of autoimmune PAP appearing as localized ground-glass opacity. An 82-year-old woman underwent chest computed tomography (CT) at another facility for cough, and a 2-cm localized ground-glass opacity was detected at the bottom of the right upper lung lobe. When she presented for follow-up at our hospital 6 months later, she was asymptomatic. The CT examinations performed at that point and 2 months thereafter did not reveal any changes. However, a CT examination performed after 5 months revealed slight increases in size and concentration. Adenocarcinoma in situ or minimally invasive adenocarcinoma was suspected. Incomplete lobulation between the upper and middle lobes of the right lung was detected, and video-assisted thoracoscopic lobectomy of the upper lobe and partial resection of the middle lobe of the right lung were performed. Histological examination revealed alveoli and terminal bronchioles filled with eosinophilic proteinaceous material positive for periodic acid-Schiff stain. The histopathological diagnosis was PAP and positive serum anti-GM-CSF antibody findings confirmed autoimmune PAP.

Preoperative graft volume assessment with 3D-CT volumetry in living-donor lobar lung transplantations.

To determine the effectiveness of living-donor lobar lung transplantation (LDLLT), it is necessary to predict the recipient's postoperative lung function. Traditionally, Date's formula, also called the segmental ratio, has used the number of lung segments to estimate the forced vital capacity (FVC) of grafts in LDLLT. To provide a more precise estimate of graft FVC, we calculated the volumes of the lower lobe and total lung using three-dimensional computed tomography (3D-CT) and the volume ratio between them. We calculated the volume ratio in 52 donors and tested the difference between the segmental volume ratios with a one-tailed t-test. We also calculated the predicted graft FVC in 21 LDLLTs using the segmental ratio pFVC(c) and the volume ratio pFVC(v), and then found the Pearson's correlation coefficients for both pFVC(c) and pFVC(v) with the recipients' actual FVC (rFVC) measured spirometrically 6 months after surgery. Significant differences were found between the segmental ratio and the average volume ratio for both sides (right, p＝0.03;left, p＝0.0003). Both pFVC(c) and pFVC(v) correlated significantly with rFVC at 6 months after surgery (p＝0.007 and 0.006). Both the conventional and the volumetric methods provided FVC predictions that correlated significantly with measured postoperative FVC.