Thin-slice Two-dimensional T2-weighted Imaging with Deep Learning-based Reconstruction: Improved Lesion Detection in the Brain of Patients with Multiple Sclerosis.

PURPOSE: Brain MRI with high spatial resolution allows for a more detailed delineation of multiple sclerosis (MS) lesions. The recently developed deep learning-based reconstruction (DLR) technique enables image denoising with sharp edges and reduced artifacts, which improves the image quality of thin-slice 2D MRI. We, therefore, assessed the diagnostic value of 1 mm-slice-thickness 2D T2-weighted imaging (T2WI) with DLR (1 mm T2WI with DLR) compared with conventional MRI for identifying MS lesions. METHODS: Conventional MRI (5 mm T2WI, 2D and 3D fluid-attenuated inversion recovery) and 1 mm T2WI with DLR (imaging time: 7 minutes) were performed in 42 MS patients. For lesion detection, two neuroradiologists counted the MS lesions in two reading sessions (conventional MRI interpretation with 5 mm T2WI and MRI interpretations with 1 mm T2WI with DLR). The numbers of lesions per region category (cerebral hemisphere, basal ganglia, brain stem, cerebellar hemisphere) were then compared between the two reading sessions. RESULTS: For the detection of MS lesions by 2 neuroradiologists, the total number of detected MS lesions was significantly higher for MRI interpretation with 1 mm T2WI with DLR than for conventional MRI interpretation with 5 mm T2WI (765 lesions vs. 870 lesions at radiologist A, < 0.05). In particular, of the 33 lesions in the brain stem, radiologist A detected 21 (63.6%) additional lesions by 1 mm T2WI with DLR. CONCLUSION: Using the DLR technique, whole-brain 1 mm T2WI can be performed in about 7 minutes, which is feasible for routine clinical practice. MRI with 1 mm T2WI with DLR enabled increased MS lesion detection, particularly in the brain stem.

Arterial Spin Labeling Was Useful for Evaluating the Treatment Response of a Transverse-Sigmoid Sinus Dural Arteriovenous Fistula: A Case Report.

Objective: We report the case of a patient in whom arterial spin labeling (ASL) was useful for assessing the effects of treatment for a transverse-sigmoid sinus dural arteriovenous fistula (TSS-dAVF). Case Presentation: The patient was a 65-year-old man. Cerebral angiography demonstrated an aggressive dAVF involving the TSS, superior sagittal sinus (SSS), and the sinus confluence, with severe cortical and deep venous reflux. We performed multiple transarterial and transvenous embolizations for the TSS and sinus confluence lesion. The shunt disappeared almost completely after embolization. A high signal intensity that had been apparent in the SSS and straight sinus (StS) on ASL imaging before embolization disappeared after embolization. ASL imaging 3 months after embolization revealed slightly a high signal intensity in the StS, which was considered to be due to recurrence of the lesion. Moreover, recurrence of the confluence and TSS-dAVF was observed on cerebral angiography 6 months after embolization. As additional embolization was considered difficult, radiation therapy was recommended, but the patient refused; therefore, follow-up was performed. As ASL imaging findings were consistent with cerebral angiography findings, careful examination and monitoring of changes on ASL imaging were subsequently performed. Conclusion: Follow-up using ASL imaging is useful to assess the effects of treatment performed for a dAVF.

The utility of two-dimensional real-time shear wave elastography for assessing liver fibrosis in patients with chronic hepatitis C virus infection.

OBJECTIVE: Two-dimensional shear wave elastography (2D-SWE) is a new ultrasound-based elastography method to evaluate liver fibrosis in the daily practice. However, the utility of 2D-SWE among the other liver fibrosis markers is unclear. METHODS: We enrolled 141 consecutive patients with hepatitis C virus infection, 66 men and 75 women (median age, 67 years), who underwent liver biopsy and 2D-SWE (LOGIQ E9, GE Healthcare, Wauwatosa, WI, USA). We compared the diagnostic accuracy of the 2D-SWE with those of magnetic resonance elastography (MRE; MR-Touch, GE Healthcare, Milwaukee, WI, USA), Mac-2 binding protein glycosylation isomer (M2BPGi), fibrosis-4 index (FIB-4) and platelet counts (PLT), using the histologic METAVIR scoring as the reference standard. RESULTS: The areas under the receiver operating characteristics curves (AUROCs) of 2D-SWE, MRE, M2BPGi, FIB-4 and PLT for ≥F2, ≥F3 and F4 were 0.86, 0.88, 0.79, 0.81 and 0.77; 0.92, 0.93, 0.86, 0.87 and 0.83; and 0.91, 0.97, 0.85, 0.85 and 0.82, respectively. For diagnosing ≥F2 and ≥F3, the AUROCs of 2D-SWE and those of MRE showed no significant differences, and both 2D-SWE and MRE showed significantly higher AUROCs than the other markers. For diagnosing F4, the AUROC of MRE was significantly higher than those of other fibrosis markers. CONCLUSION: 2D-SWE has an excellent diagnostic accuracy equivalent to that of MRE for assessing significant (≥F2) and severe (≥F3) fibrosis. MRE demonstrated a higher AUROC than 2D-SWE, but this last one has advantages such as lower cost, fewer contraindications and greater ease of performance than MRE.

High-signal venous sinuses on MR angiography: discrimination between reversal of venous flow and arteriovenous shunting using arterial spin labeling.

PURPOSE: It is sometimes difficult to differentiate between high signals originating from a reverse flow on magnetic resonance angiography (MRA) and occult arteriovenous shunting. We attempted to determine whether arterial spin labeling (ASL) can be used to discriminate reversal of venous flow from arteriovenous shunting for high-signal venous sinuses on MR angiography. METHODS: Two radiologists evaluated the signals of the venous sinus on MRA and ASL obtained from 364 cases without arteriovenous shunting. In addition, the findings on MRA were compared with those on ASL in an additional 13 patients who had dural arteriovenous fistula (DAVF). RESULTS: In the 364 cases (728 sides) without arteriovenous shunting, a high signal due to reverse flow in the cavernous sinuses (CS) was observed on 99 sides (13.6%) on MRA and none on ASL. Of these cases, a high signal in the sigmoid sinus, transverse sinus, and internal jugular vein was seen on 3, 3, and 8 sides, respectively. All of these venous sinuses showed a high signal from the reverse flow on MRA images. CONCLUSION: ASL is a simple and useful MR imaging sequence for differentiating between reversal of venous flow and CS DAVF. In the sigmoid and transverse sinus, ASL showed false-positives due to the reverse flow from the jugular vein, which may be a limitation of which radiologists should be aware.

Temporal variations in stump pressure and assessment of images obtained from cone-beam computed tomography during balloon-occluded transarterial chemoembolization.

AIM: Balloon-occluded transcatheter arterial chemoembolization (B-TACE) was used to show the optimized duration of balloon occlusion to start injection of lipiodol in order to maximize lipiodol deposition in the nodule, and to reveal the endpoint of lipiodol injection. METHODS: Of 29 consecutive patients who underwent balloon-occluded TACE between November 2013 and February 2014, we were able to measure stump pressure for 219 nodules in 27 patients. Tumors were counted, measured and could be visually assessed in 20 of these patients at 26 sites. Tumors with multiple feeders were found in eight patients. Arterial blood pressure was measured before, immediately after and 5 min after balloon occlusion prior to intra-arterial injection, as well as before and after balloon deflation after intra-arterial injection. Images were assessed qualitatively by two radiologists as well as quantitatively by calculating the contrast-to-noise ratio. RESULTS: We found no significant difference in pressure between immediately after and 5 min after balloon occlusion. Mean stump pressure before balloon deflation after intra-arterial injection was 70.4 mmHg. We observed a significant increase in qualitative scores after balloon occlusion (P < 0.001), and the mean score in the third-order branch was significantly higher than that in the first-order branch (P = 0.048). CONCLUSION: Our results indicate that intra-arterial injection can be started at any time after balloon occlusion and that 70 mmHg may be considered as a possible indicator of the end-point for arterial injection.

Contribution of dynamic sentinel lymphoscintigraphy images to the diagnosis of patients with malignant skin neoplasms in the upper and lower extremities.

The aim of the present study was to confirm the contribution of dynamic images in sentinel lymphoscintigraphy in malignant skin neoplasms: precisely, to investigate if dynamic images were necessary and to observe if dynamic images could reduce the areas needed for biopsy and dissection. Twenty-five patients with malignant skin neoplasms of the lower (n = 21) and upper (n = 4) extremities were retrospectively investigated. Images were evaluated by two independent reviewers, an expert in diagnostic radiology and nuclear medicine and a diagnostic radiologist in training. Visualized hot spots were assessed to be sentinel nodes using only static planar images. Next, both static planar and dynamic images were assessed. Reviewers scored diagnostic confidence values of determined sentinel nodes as follows: 0, cannot be decided; 1, possible; 2, probable; and 3, definitive. Patterns of lymphatic drainage were categorized into six different pathways: (1) inguinal type, (2) popliteal type, (3) inguinal and popliteal type, (4) axillary type, (5) cubital type, and (6) axillary and cubital type. In cases in the lower extremities, with dynamic images, the expert reviewer changed assessment in three cases and the trainee reviewer changed it in one case. There were no cases in which a decision was changed to be the same between both reviewers. Although the average diagnostic confidence value of assessment is usually higher with dynamic images, significant differences were not present. In cases of the upper extremities, both reviewers changed their assessment in one patient. By mutual agreement, cases in which assessment was changed with dynamic images were the inguinal and popliteal type, and the axillary and cubital type. The expert reviewer noticed lymphatic channels only visualized on dynamic images and changed assessment. Determination of whether or not a lymph node is a sentinel node depends on visualization of the lymphatic network. In the present circumstances, all biopsies of hot spots determined to be lymph nodes should not be excluded. However, excessive biopsies should be avoided as much as possible. It is necessary to use dynamic images alongside skillful observation.

Lymphoscintigraphy for sentinel lymph node mapping in Japanese patients with malignant skin neoplasms of the lower extremities: comparison with previously investigated Japanese lymphatic anatomy.

OBJECTIVES: Lymph nodes (LN) and lymphatic drainage were identified by lymphoscintigraphy using 99(m)Tc-phytate in order to map the sentinel lymph nodes (SLNs) in patients with malignant skin neoplasms of the lower extremities, and to compare the results with an atlas of Japanese lymphatic anatomy. METHODS: Sentinel lymphoscintigraphs of 18 patients with malignant skin neoplasms of the lower extremities (9 men, 9 women; age range 45-84 years, mean age 66 years) were analyzed retrospectively, and the LNs detected were identified as SLNs or secondary nodes. RESULTS: The patterns of lymphatic drainage were divided into three different categories: (1) initial drainage into inguinal LN without visualization of popliteal LNs (inguinal type), (2) initial drainage into popliteal LNs and then into intrapelvic LNs (popliteal type), and (3) initial drainage into both popliteal and inguinal LNs (inguinal and popliteal type). More than half of the cases were the inguinal and popliteal type, as both inguinal and popliteal LNs were identified as SLNs. In the cases in which the hallux and its surrounding area were injected, all were the inguinal type and popliteal LNs were not visualized. In one case, only dynamic images detected lymphatic drainage without visualization of popliteal LNs. In contrast to the previously published literature on Japanese lymphatic anatomy, SLN lymphatic drainage from the skin of the lower extremities was wide and overlapping in many areas. However, in agreement with currently accepted anatomy, only the great saphenous lymphatic vessel drained the skin of the hallux and its surrounding area. The present results suggest that it is important to confirm lymphatic drainage in order to identify SLNs in the lower extremities. CONCLUSIONS: The patterns of lymphatic drainage from the skin of the foot were divided into three different categories. In contrast to previously published Japanese lymphatic anatomy, lymphatic drainage from the skin of the lower extremities was wide and overlapping in many areas. However, only the great saphenous lymphatic vessel drained the skin of the hallux and its surrounding area in agreement with currently accepted Japanese lymphatic anatomy. It is important to confirm lymphatic drainage to identify SLNs in the lower extremities.