Evaluation of MR imaging findings differentiating parotid basal cell adenomas from other parotid tumors.

PURPOSE: To evaluate the usefulness of magnetic resonance imaging (MRI) to differentiate basal cell adenomas (BCAs) from other parotid tumors. METHOD: A total of 136 patients with histologically proven parotid gland tumors (13 BCAs, 66 pleomorphic adenomas [PAs], 30 Warthin tumors [WTs], and 27 parotid cancers [PCs]) who underwent a cervical MRI study between December 2011 and March 2019 were retrospectively enrolled. The MRI findings of the tumors were evaluated by two board-certified radiologists. RESULTS: All 13 of the BCAs showed smooth margins, while 19 of the 27 PCs showed irregular margins (p < 0.0001). Eleven BCAs had some cystic components, and five were cyst-dominant. The BCAs had significantly more cystic components than the PAs (p = 0.0077). The mean apparent diffusion coefficient (ADC) value of the BCAs was 1.21 ± 0.20 × 10-3 mm2/sec, which was equivalent to that of the PCs (1.12 ± 0.25 × 10-3 mm2/sec, p = 0.76), significantly lower than that of the PAs (1.61 ± 0.32 × 10-3 mm2/sec, p < 0.0001), and significantly higher than that of the WTs (0.81 ± 0.19 × 10-3 mm2/sec, p = 0.0004). The plateau time-intensity curve (TIC) was the most common type for both BCAs and PCs, seen in 8 of 12 BCAs and 21 of 26 PCs, with no significant difference between these groups (p = 0.34). CONCLUSIONS: BCA should be considered a possibility when a parotid lesion has smooth margins with an entire capsule and includes a cystic component, even if the TIC and diffusion-weighted MR images suggest a malignant pattern.

Characterization of parotid gland tumors: added value of permeability MR imaging to DWI and DCE-MRI.

OBJECTIVES: To determine added value of permeability MRI in parotid tumor characterization to T2-weighted imaging (T2WI), semi-quantitative analysis of time-intensity curve (TIC), and intra-voxel incoherent motion diffusion-weighted imaging (IVIM-DWI). METHODS: This retrospective study was approved by the institutional review board, and the informed consent was waived. Sixty-one parotid tumors in 61 patients were examined using T2WI, IVIM-DWI, and permeability MRI. TIC patterns were categorized as persistent, washout, or plateau. Signal intensity ratio of lesion-to-muscle on T2WI, apparent diffusion coefficients (ADCs), D and f values from IVIM-DWI, and Ktrans, kep, Ve, and Vp values from permeability MRI were measured. Multiple comparisons were applied to determine whether any differences among 4 histopathologic types (pleomorphic adenomas, Warthin's tumors, other benign tumors, and malignant tumors) existed. Diagnostic accuracy was compared before and after modification diagnosis referring to permeability MRI. In a validation study, 60 parotid tumors in 60 patients were examined. RESULTS: ADC and D values of malignant tumors were significantly lower than those of benign tumors other than Warthin's tumors, but higher than those of Warthin's tumors. kep and Vp values of Warthin's tumors were significantly higher than those of malignant tumors. Multivariate analyses showed that TIC pattern, D, and kep values were suitable parameters. McNemar's test showed a significant increase of sensitivity (11/12, 92%) and specificity (46/49, 94%) with adding kep. The validation study yielded high sensitivity (14/16, 88%) and specificity (41/44, 93%). CONCLUSION: Permeability MRI offers added value to IVIM-MRI and semi-quantitative TIC analysis of DCE-MRI in characterization of parotid tumors KEY POINTS: • Permeability MR imaging offers added value in the characterization of parotid gland tumors in combination with semi-quantitative TIC analysis and IVIM analyses with D parameter. • The combination of TIC pattern, D, and kep might facilitate accurate characterization of parotid gland tumor, thereby avoiding unnecessary surgery for benign tumors or delayed treatment for malignant tumors. • A combination of permeability and diffusion MR imaging can be used to guide the selection of an appropriate biopsy site.

Amide proton transfer (APT) imaging of parotid tumors: Differentiation of malignant and benign tumors.

PURPOSE: To assess the usefulness of amide proton transfer (APT) imaging in differentiating parotid tumors. MATERIAL AND METHODS: We retrospectively analyzed 43 histopathologically proven parotid solid tumors with diameters ≥2 cm. Twenty-one tumors were benign and 12 tumors were malignant. Two-dimensional APT imaging was performed using a saturation pulse with a duration of 2 s and a saturation power level of 2 µT. For acquiring Z-spectra, the imaging was repeated at 25 saturation frequency offsets from ω = -6 to +6 ppm with a step of 0.5 ppm as well as one scan acquired far off-resonance (-1560 ppm) for signal normalization. For the APT imaging, the asymmetry analysis at 3.5 ppm downfield from the water signal was calculated. The mean APT signal intensity (SI) was compared between the benign and malignant tumors. RESULTS: The mean APT SI was 2.23 ± 0.80 % in the benign tumors and significantly higher at 2.99 ± 0.99 % in the malignant tumors (P = 0.01). A receiver operating curve analysis revealed that the optimal APT SI threshold was 2.40 for distinguishing malignant tumors from benign tumors with an area under the curve of 0.74. The sensitivity, specificity, and accuracy were 83.3%, 61.3%, and 67.4%, respectively. CONCLUSION: The mean APT SI of the malignant parotid tumors was significantly higher than that of the benign parotid tumors.

Balloon pulmonary angioplasty improves right atrial reservoir and conduit functions in chronic thromboembolic pulmonary hypertension.

AIMS: Right atrial (RA) function largely contributes to the maintenance of right ventricular (RV) function. This study investigated the effect of balloon pulmonary angioplasty (BPA) on RA functions in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) using cardiac magnetic resonance imaging (CMRI). METHODS AND RESULTS: CMRI and RV catheterization were performed before BPA sessions and at the follow-up periods in 29 CTEPH patients. Reservoir [RA longitudinal strain (RA-LS)], passive conduit [RA early LS rate (LSR)], and active (RA late LSR) phases were assessed by using cine CMRI and a feature-tracking algorithm. The relationships between the changes in RA functions and in brain natriuretic peptide (BNP) were evaluated in both the dilated and non-dilated RA groups. RA-LS (32.4% vs. 42.7%), RA LSR (6.3% vs. 8.3%), and RA early LSR (-2.3% vs. -4.3%) were improved after BPA, whereas no significant change was seen in RA late LSR. The changes in RA peak LS and in RA early LSR were significantly correlated with the changes in BNP (ΔRA-LS: r = -0.63, ΔRA-early LSR: r = 0.65) and pulmonary vascular resistance (PVR) (ΔRA-LS: r = -0.69, ΔRA-early LSR: r = 0.66) in the nondilated RA group. CONCLUSION: The RA reservoir and passive conduit functions were impaired in inoperable CTEPH, whereas RA active function was preserved. BPA markedly reversed these impaired functions. The improvements in RA reservoir and conduit functions were significantly correlated with the changes in BNP levels and PVR in CTEPH patients with normal RA sizes.

Effectiveness of therapeutic standard concentration barium enema for colonic diverticular bleeding: Preliminary results.

PURPOSE: To evaluate the effectiveness of a therapeutic barium enema as a treatment for colonic diverticulum bleeding, by using a standard concentration as a diagnostic examination. METHODS: We retrospectively analyzed 68 cases of the patients admitted to our hospital with colonic diverticular bleeding between October 2012 and September 2017. We evaluated the following items: (1) the presence/absence of a previous history of diverticular bleeding, (2) the use of medications (anticoagulants, nonsteroidal anti-inflammatory drugs, and antiplatelet drugs), (3) the location of bleeding, (4) the presence/absence of previous treatment and the result, (5) the time between bleeding and the beginning of the barium enema, (6) procedural success, (7) the clinical success of the initial hemostasis, (8) the clinical success of preventing recurrence, and (9) complications such as perforation and diverticulitis associated with this procedure. RESULTS: Four patients (three men and one woman; age range 60-85 years; median age 76 years) who underwent therapeutic barium enema with a concentration equivalent for diagnostic purpose (78 w/v%) were included. The follow-up period ranged from 11 to 12 months (median 12 months). All three patients who received a barium enema for initial hemostasis were successfully treated. All four patients remained free from recurrence during the follow-up period. There was no complication due to barium in this series. CONCLUSION: Although we had no statistical evidence, a therapeutic barium enema with a standard concentration as a diagnostic examination may be effective for both the initial hemostasis and preventing the recurrence of colonic diverticular bleeding without complications.