Misa Sumi

MR Microimaging of Benign and Malignant Nodes in the Neck

OBJECTIVE We evaluated the diagnostic criteria of high-resolution MRI in differentiating benign and malignant cervical nodes that were palpable and superficial in the neck. SUBJECTS AND METHODS We performed MR microimaging on 24 histologically proven metastatic nodes, 14 histologically proven lymphomas, and 35 histologically or clinically proven benign nodes in the necks of 26 patients. The lymph nodes were imaged with T1-weighted spin-echo, fat-suppressed T2-weighted turbo spin-echo, and spin-echo diffusion-weighted echo-planar sequences using a 47-mm microscopy coil. RESULTS MR microimaging provided high-resolution images of the nodes. Hilar fat was lost in 92%, 79%, and 46% of the metastatic nodes, lymphomas, and benign nodes, respectively. Smooth nodal margins were lost in 58%, 23%, and 9% of metastatic nodes, lymphomas, and benign nodes, respectively. Heterogeneous nodal parenchyma on T1- or fat-suppressed T2-weighted images, or both, was observed in 88%, 29%, and 23% of metastatic nodes, lymphomas, and benign nodes, respectively. The apparent diffusion coefficients were significantly different among these three node groups (p < 0.001), with metastatic nodes being the highest, followed by benign nodes. Logistic regression analyses showed that heterogeneous nodal parenchyma and apparent diffusion coefficient levels were significant in discriminating metastatic nodes, and apparent diffusion coefficient levels in discriminating lymphomas. Combined use of these MR microscopic criteria on nodal architecture and apparent diffusion coefficients yielded 90% accuracy (86% sensitivity, 94% specificity) and 93% accuracy (85% sensitivity, 95% specificity) for discriminating metastatic nodes and lymphomas, respectively. CONCLUSION The nodal architecture and apparent diffusion coefficient levels on MR microimaging may provide useful information in diagnosing benign and malignant nodes in the neck.

Salivary Gland Tumors: Use of Intravoxel Incoherent Motion MR Imaging for Assessment of Diffusion and Perfusion for the Differentiation of Benign from Malignant Tumors

PURPOSE To prospectively evaluate the intravoxel incoherent motion (IVIM) parameters (microvascular volume fraction, f; pure diffusion coefficient, D; and perfusion-related incoherent microcirculation, D*) for differentiating between benign and malignant salivary gland tumors. MATERIALS AND METHODS All participants in this prospective institutional review board-approved study provided written informed consent. The perfusion and diffusion of 20 (65%) benign (12 pleomorphic adenomas and eight Warthin tumors) and 11 (35%) malignant salivary gland tumors were assessed on the basis of the IVIM theory. Diffusion-weighted magnetic resonance imaging was performed by using 11 b values (0-800 sec/mm(2)). The IVIM parameters of the salivary gland tumors were determined by a radiologist, and significant differences between the tumor types were assessed by using the Steel-Dwass test. RESULTS The f values of Warthin tumors (0.156 ± 0.039 [standard deviation]) were significantly larger than those of pleomorphic adenomas (0.066 ± 0.031) (P = .003). The D values of malignant tumors (0.96 × 10(-3) mm(2)/sec ± 0.22) were significantly different from those of benign tumors (pleomorphic adenomas, 1.38 × 10(-3) mm(2)/sec ± 0.30 [P = .002]; Warthin tumors, 0.61 × 10(-3) mm(2)/sec ± 0.11 [P = .005]). The D* values of malignant tumors (21.99 × 10(-3) mm(2)/sec ± 19.01) were significantly smaller than those of Warthin tumors (42.64 × 10(-3) mm(2)/sec ± 20.17) (P = .022). The combination of D and D* criteria provided the best diagnostic accuracy (100%) for differentiation among the three tumor types. CONCLUSION IVIM imaging may be helpful for differentiation between benign and malignant salivary gland tumors.

MR factor analysis: improved technology for the assessment of 2D dynamic structures of benign and malignant salivary gland tumors.

To establish an MR factor analysis technique for two‐dimensional (2D) MR dynamic structures of benign and malignant salivary gland tumors.

Nodal imaging in the neck: recent advances in US, CT and MR imaging of metastatic nodes

The presence of lymph node metastasis in the neck in patients with head and neck cancer is an important prognostic determinant in staging cancers and in planning surgery and chemo- and radiotherapy for the cancer patients. Therefore, metastatic nodes should be effectively differentiated from benign lymphadenopathies and nodal lymphomas. Here, we review recent advances in the diagnostic imaging of metastatic nodes in the neck, with emphasis placed on the diagnostic performance of MR imaging, Doppler sonography, and CT.

Apparent diffusion coefficient mapping for sinonasal diseases: differentiation of benign and malignant lesions.

Because CT and conventional MR imaging findings of sinonasal lesions overlap considerably, these authors decided to evaluate the utility of diffusion-weighted imaging in differentiating these lesions. They obtained apparent diffusion coefficient values in 61 proved lesions (19 benign, 28 malignant, and 14 inflammatory). As expected, ADC values of malignant lesions were much lower than those of the other 2 types. Additionally, the higher the percentage area of the tumor that had low ADC, the greater was the chance of it being malignant. If 78% of lesion area had low ADC, the ability to differentiate between malignant and benign reached a 94% specificity. ADCs could also differentiate lymphoma from other malignant tumors. Conclusions: ADC mapping may be an effective MR imaging tool for the differentiation of benign/inflammatory lesions from malignant tumors in the sinonasal area. BACKGROUND AND PURPOSE: CT and MR imaging features of benign and malignant sinonasal lesions are often nonspecific. Therefore, we evaluated the ADC-based differentiation of these lesions. MATERIALS AND METHODS: We retrospectively assessed ADCs of 61 patients with histologically proved sinonasal tumors and tumorlike lesions: 19 benign lesions, 28 malignant tumors, and 14 inflammatory lesions. Overall ADCs and percentages of total tumor area with extremely low, low, intermediate, or high ADCs (ADC mapping) were determined by using 2 b-values (500 and 1000 s/mm2). RESULTS: ADCs of malignant tumors (0.87 ± 0.32 × 10−3 mm2/s) were significantly lower than those of benign (1.35 ± 0.29 × 10−3 mm2/s, P < .0001) and inflammatory (1.50 ± 0.50 × 10−3 mm2/s, P = .0002) lesions. On ADC mapping, percentages of total tumor area within malignant tumors having extremely low or low ADCs were significantly (P < .0001) greater than those within benign and inflammatory lesions. Cutoff points for ADC mapping (≥78% of tumor areas having extremely low or low ADCs) effectively differentiated benign or inflammatory lesions and malignant tumors with 75% sensitivity, 94% specificity, 85% accuracy, and 91% positive and 82% negative predictive values, respectively. ADCs also effectively discriminated lymphomas and SCCs from other malignant tumors. CONCLUSIONS: ADC mapping may be an effective MR imaging tool for the differentiation of benign/inflammatory lesions from malignant tumors in the sinonasal area.

Multiparametric magnetic resonance imaging for the differentiation between benign and malignant salivary gland tumors

To evaluate the stepwise approach in differentiating between benign and malignant salivary gland tumors using time‐intensity curves (TICs) and apparent diffusion coefficients (ADCs).

Head and Neck Tumors: Assessment of Perfusion-Related Parameters and Diffusion Coefficients Based on the Intravoxel Incoherent Motion Model

BACKGROUND AND PURPOSE: IVIM MR imaging provides perfusion and diffusion information with a single diffusion-weighted MR image. We determined whether PP and D differ among various types of head and neck tumors. MATERIALS AND METHODS: The study cohort included 123 head and neck tumors: 30 SCCs, 28 benign and 20 malignant SG tumors, 36 lymphomas, and 9 schwannomas. The D and PP values were determined by using b-values of 0, 500, and 1000 s/mm2 based on the IVIM model. RESULTS: The PP values (lymphomas, 0.09 ± 0.04; SCCs, 0.15 ± 0.04; and malignant SG tumors, 0.22 ± 0.07) and D values (0.47 ± 0.07 × 10−3 mm2/s, 0.82 ± 0.17 × 10−3 mm2/s, and 1.03 ± 0.16 × 10−3 mm2/s, respectively) were significantly different among the malignant tumors (P < .01). These values were also significantly different between pleomorphic adenomas (0.13 ± 0.02 and 1.44 ± 0.39 × 10−3 mm2/s) and Warthin tumors (0.19 ± 0.04 and 0.73 ± 0.22 × 10−3 mm2/s) (P < .001). The PP values of malignant SG tumors were significantly different from those of pleomorphic adenomas (P = .001) and the D values of the malignant SG tumors were significantly different from those of pleomorphic adenomas (P = .002) and Warthin tumors (P = .007). Schwannomas had large PP (0.23 ± 0.08) and D values (1.26 ± 0.20 × 10−3 mm2/s), greatly overlapping those of some SG tumor types. CONCLUSIONS: Head and neck tumors had distinctive PP and D values by using IVIM MR imaging.

Sonography as a replacement for sialography for the diagnosis of salivary glands affected by Sjögren's syndrome

Recently, it has been suggested that sonographic evaluation of the salivary glands is useful in the diagnosis of Sjogrens syndrome. Kawamura et al and, more recently, Ariji et al , showed that descriptive and quantitative assessment of the salivary glands by sonography efficiently differentiated between diseased and normal glands in patients with Sjogrens syndrome.1,2 They showed that the proposed sonographic gradings correlated well with the sialographic gradings. These findings suggest that sonography might be an alternative diagnostic tool for Sjogrens syndrome. Here, we attempted to determine whether sonography can take the place of sialography as an alternative technique for the assessment of salivary gland involvement in Sjogrens syndrome. Sialography and sonography were performed on 294 patients who presented with sicca syndrome (171 positive and 123 negative for Sjogrens syndrome). We diagnosed patients with Sjogrens …

Efficacy of Diffusion-Weighted Imaging for the Differentiation between Lymphomas and Carcinomas of the Nasopharynx and Oropharynx: Correlations of Apparent Diffusion Coefficients and Histologic Features

BACKGROUND AND PURPOSE: ADCs may help distinguish benign from malignant head and neck diseases. We sought to evaluate the effectiveness of ADC for differentiating between carcinomas and lymphomas of the nasopharynx and oropharynx. MATERIALS AND METHODS: We retrospectively compared the ADCs between 24 histologically proved lymphomas and 32 carcinomas, including 8 NPCs and 7 lymphomas of the nasopharynx, and 24 SCCs and 17 lymphomas of the oropharynx. ADCs were determined on tumor-by-tumor (overall ADCs) and pixel-by-pixel (ADC mapping) bases by using 2 b-values (500 and 1000 s/mm2). RESULTS: Lymphomas and oropharyngeal SCCs had unique histologic features in terms of keratinization, cell attenuation, stromal areas, and necrosis and had distinctive ADCs (0.503 ± 0.099 × 10−3 mm2/s for lymphomas and 0.842 ± 0.164 × 10−3 mm2/s for SCCs). However, NPCs and lymphomas were similar in terms of these histologic features, exhibiting comparable ADCs (0.567 ± 0.057 × 10−3 mm2/s for NPCs and 0.528 ± 0.094 × 10−3 mm2/s for lymphomas). Poorly and moderately differentiated SCCs with homogeneous T2 signals were indistinguishable from lymphomas on conventional MR images; however, ADCs of these SCC subtypes were significantly larger than those of lymphomas. ADC mapping profiles with respect to percentage of tumor areas of extremely low, intermediate, and high ADC levels were well-correlated with the histologic features of lymphomas, NPCs, and different types of SCCs. CONCLUSIONS: The effectiveness of ADC-based differentiation between lymphomas and carcinomas of the nasopharynx and oropharynx depends on their histologic characteristics.

Diffusion-Weighted MR Imaging of Ameloblastomas and Keratocystic Odontogenic Tumors: Differentiation by Apparent Diffusion Coefficients of Cystic Lesions

BACKGROUND AND PURPOSE: Ameloblastomas and keratocystic odontogenic tumors are major aggressive odontogenic tumors in the maxillomandibular regions, but the differentiation between these 2 tumors is frequently ineffective based on only conventional CT and MR imaging findings. Here, we evaluated diffusion-weighted MR imaging for the differentiation of these 2 odontogenic tumors. MATERIALS AND METHODS: We prospectively studied 9 patients with ameloblastoma and 7 patients with keratocystic odontogenic tumor using diffusion-weighted MR imaging. Apparent diffusion coefficients (ADCs) of the nonenhancing and solid lesions in these tumors were determined with use of 2 b factors (500 and 1000). RESULTS: Two types of nonenhancing lesions were identified; one with high signal intensity on fat-suppressed T2-weighted images (type A) and the other with low or intermediate intensity (type B). The type A nonenhancing lesions were observed in all the ameloblastomas, but they were evident in only 2 keratocystic odontogenic tumors. It is interesting to note that the ADCs of the nonenhancing lesions in the ameloblastomas were significantly higher than those of the nonenhancing lesions in the keratocystic odontogenic tumors (2.48 ± 0.20 × 10−3 mm2/s vs 1.13 ± 0.56 × 10−3 mm2/s; P < .001). The ADCs of the solid lesions in the ameloblastomas (1.39 ± 0.15 × 10−3 mm2/s) were significantly lower than those of the nonenhancing lesions in the ameloblastomas and were similar to those of the nonenhancing lesions in the keratocystic odontogenic tumors. CONCLUSION: ADC determination may be used as an adjunct tool for differentiation between ameloblastomas and keratocystic odontogenic tumors.