Pembrolizumab-Associated Pneumonitis Resembling Lymphangitic Carcinomatosis in a Melanoma Patient.

ABSTRACT: In recent years, many articles have described the adverse events associated with immune checkpoint inhibitors. We report the case of a 63-year-old woman with bilateral lung shadows after 1-year pembrolizumab immunotherapy following surgery for the right-foot melanoma because of positive sentinel lymph nodes. Follow-up 18 F-FDG PET/CT demonstrated bilateral diffuse mass-like peribronchovascular opacities with marked FDG uptake. Clinically, melanoma metastases with lymphangitic spread were suspected, and bronchoscopy was performed, although no evidence of malignancy was found. The lung shadow was mostly resolved after steroid treatment. Pembrolizumab-induced pneumonitis can be a mimicker of melanoma metastasis with lymphangitic spread.

Quantitative non-Gaussian diffusion and intravoxel incoherent motion magnetic resonance imaging: differentiation of malignant and benign breast lesions.

OBJECTIVES: The purpose of this study was to explore the potential of non-Gaussian diffusion and perfusion magnetic resonance imaging (MRI) using intravoxel incoherent motion (IVIM) MRI for the diagnosis of breast lesions. MATERIALS AND METHODS: This study included 26 women with breast lesions. Diffusion-weighted images were acquired using 16 b values up to 2500 s/mm and analyzed using a kurtosis diffusion model (apparent diffusion coefficient [ADC0] and kurtosis [K]) for the diffusion component and IVIM model (perfusion fraction [fIVIM] and pseudodiffusion coefficient [D*]) for the perfusion component. Diagnostic performance of diffusion and perfusion parameters was evaluated from receiver operating characteristic analyses. RESULTS: The ADC0 in malignant lesions was significantly lower than that in benign lesions and normal tissue (P < 0.001, P < 0.001), whereas K was significantly higher (P < 0.05, P < 0.001), as well as fIVIM (P < 0.05, P < 0.01). No significant difference was found in D*. The receiver operating characteristic analysis gave high area under the curve values for ADC0, K, and fIVIM for distinguishing malignant from benign lesions (0.99, 0.85, and 0.82, respectively). The ADC0 allowed benign tumors to be identified with 100% negative predictive value and malignant tumors with 100% sensitivity. The malignant/benign diagnosis thresholds were 1.4 × 10 mm/s as well as 0.6 and 7%, respectively, for ADC0, K, and fIVIM. CONCLUSIONS: With a proper methodological framework, IVIM MRI can provide valuable information on tissue structure and microvasculature beneficial for the diagnosis of breast cancer lesions.

Automated detection and measurement of uterine peristalsis in cine MR images.

PURPOSE: To evaluate the ability of automated software to quantify uterine peristalsis on cine magnetic resonance imaging (MRI). MATERIALS AND METHODS: At 1.5T, half-Fourier acquisition single-shot turbo spin echo (HASTE) techniques were used to obtain 60 serial images over 3 minutes (TR/TE 3000/80 msec) in a midsagittal plane of the uterus. Thirty-two cine MR datasets, obtained from 16 healthy females, were analyzed. Uterine peristalsis was defined as the traveling waves of decreasing signal intensity on the endometrium-junctional zone border. The software detected traveling waves by identifying the neighboring areas showing similar patterns of signal intensity decrease in a different timing. Quantification of uterine peristaltic wave using the fully automated software was compared to qualitative visual evaluation by two readers. RESULTS: The mean number (and standard deviation) of peristaltic waves detected by the fully automated software and visual evaluations (readers 1 and 2) were 5.4 (3.0), 4.7 (3.1), and 4.5 (3.1) per 3 minutes, respectively. Quantification by fully automated software demonstrated excellent agreement with repeated measurement (weighted kappa 0.99) and with qualitative visual evaluations (range 0.89-0.95), comparable to interreader agreement by visual evaluations (range 0.89-0.93). CONCLUSION: The fully automated software can be used to quantify uterine peristalsis comparable to visual evaluation.

Characterization of glioma microcirculation and tissue features using intravoxel incoherent motion magnetic resonance imaging in a rat brain model.

PURPOSE: Our aim was to investigate the pertinence of diffusion and perfusion magnetic resonance imaging (MRI) parameters obtained at 17.2 T in a 9L glioma rat brain tumor model to evaluate tumor tissue characteristics. MATERIALS AND METHODS: The local animal ethics advisory committee approved this study. 9L glioma cells were injected intracerebrally to 14 Fischer rats. The animals were imaged at 7 or 12 days after implantation on a 17.2-T MRI scanner, using 72 different b values (2-3025 s/mm(2)). The signal attenuation, S/So, was fitted using a kurtosis diffusion model (ADCo and K) and a biexponential diffusion model (fractions ffast and fslow and diffusion coefficients Dfast and Dslow) using b values greater than 300 s/mm(2). To bridge the 2 models, an average diffusion coefficient and a biexponential index were estimated from the biexponential model as ADCo and K equivalents, respectively. Intravoxel incoherent motion perfusion-related parameters were obtained from the residual signal at low b values, after the diffusion component has been removed. Diffusion and perfusion maps were generated for each fitted parameter on a pixel-by-pixel basis, and regions of interest were drawn in the tumor and contralateral side to retrieve diffusion and perfusion parameters. All rats were killed and cellularity and vascularity were quantitatively assessed using histology for comparison with diffusion and perfusion parameters. RESULTS: Intravoxel incoherent motion maps clearly highlighted tumor areas as generally heterogeneous, as confirmed by histology. For diffusion parameters, ADCo and were not significantly different between the tumor and contralateral side, whereas K in the tumor was significantly higher than in contralateral basal ganglia (P < 0.0001), as well as biexponential index (P < 0.001). ADCo and in the tumor at day 7 were significantly higher than at day 12 (P < 0.01 and P < 0.001, respectively). fIVIM in the tumor from the kurtosis diffusion model was significantly higher than in contralateral basal ganglia (P < 0.001). fIVIM in the tumor at day 7 was significantly higher than in the tumor at day 12 (P < 0.0001). There was no significant difference for D* between the tumor and contralateral side (P = 0.06). A significant negative correlation was found between tumor vascularity and fIVIM (P < 0.05) as well as between tumor cell count and (P < 0.01). CONCLUSION: Quantitative non-Gaussian diffusion and perfusion MRI can provide valuable information on microvasculature and tissue structure to improve characterization of brain tumors.