Keizo Tanitame

Diffusion tensor imaging of peripheral nerve in patients with chronic inflammatory demyelinating polyradiculoneuropathy: a feasibility study

IntroductionThe purpose of this study was to assess the clinical feasibility of diffusion tensor imaging (DTI) for the evaluation of peripheral nerves in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).MethodsUsing a 3-T magnetic resonance imaging scanner, we obtained DTI scans of the tibial nerves of 10 CIDP patients and 10 sex- and age-matched healthy volunteers. We prepared fractional anisotropy (FA) maps, measured the FA values of tibial nerves, and compared these values in the two study groups. In nine patients, we also performed tibial nerve conduction studies and analyzed the correlation between the FA values and parameters of the nerve conduction study.ResultsThe tibial nerve FA values in CIDP patients (median 0.401, range 0.312–0.510) were significantly lower than those in healthy volunteers (median 0.530, range 0.469–0.647) (Mann–Whitney test, p < 0.01). They were significantly correlated with the amplitude of action potential (Spearman correlation coefficient, p = 0.04, r = 0.86) but not with nerve conduction velocity (p = 0.79, r = 0.11).ConclusionOur preliminary data suggest that the noninvasive DTI assessment of peripheral nerves may provide useful information in patients with CIDP.

Effect of age on the fractional anisotropy (FA) value of peripheral nerves and clinical significance of the age-corrected FA value for evaluating polyneuropathies

IntroductionWe investigated the correlation between age and the fractional anisotropy (FA) values of peripheral nerves in healthy adults and compared the age-corrected FA values of peripheral nerves in healthy subjects and patients with polyneuropathy.MethodsThe institutional review board approved this study and informed consent was obtained from all participants before entry into the study. We optimized diffusion tensor imaging using a 3-T magnetic resonance scanner and an extremity coil for scanning tibial nerves. The effect of age and sex on the FA values of tibial nerves in healthy volunteers was investigated and the age-corrected FA values of tibial nerves in healthy volunteers and patients with polyneuropathy were compared.ResultsThe maximum FA values of the tibial nerves remained constant until age 45 (approximately 0.516); they subsequently decreased by 0.004/year in healthy volunteers. After removing the effect of age with an age-adjusted equation, the median maximum FA values in the volunteers and patients were 0.518 (range, 0.406–0.616) and 0.442 (range, 0.376–0.530), respectively. The age-corrected FA values were significantly lower in the patients than the healthy volunteers (p < 0.001). There was no significant gender-related difference in the maximum FA values of the tibial nerves (p = 0.416).ConclusionThe age-corrected FA value of the peripheral nerves helps to differentiate between age-related peripheral nerve degeneration and polyneuropathies.

Evaluation of lumber nerve root compression using thin-slice thickness coronal magnetic resonance imaging: three-dimensional fat-suppressed multi-shot balanced non-steady-state free precession versus threedimensional T1-weighted spoiled gradient-recalled echo

PurposeThe aim of this study was to compare the three-dimensional fat-suppressed balanced non-steady-state free precession (3D FS-nSSFP) sequence and the 3D T1-weighted spoiled gradient-recalled echo (3D T1-GRE) sequence for evaluating lumbar nerve root compression with continuous thin-slice coronal magnetic resonance (MR) images.Materials and methodsThe institutional review board approved this study, and written informed consent was obtained from all 35 patients. We optimized continuous 2.5-mm thick lumbar coronal images with 3D FS-nSSFP and 3D T1-GRE. We calculated the contrast-to-noise ratio (CNR) for nerve roots and other structures on images with the two sequences. With knowledge of the final diagnosis, we assessed the visibility of nerve root compression on these images.ResultsThe CNR values of nerve roots were significantly higher on images with 3D FS-nSSFP than on those with 3D T1-GRE. These continuous thin-slice coronal images facilitated visualization of nerve root compression in >91% of patients. There was no statistically significant difference between the two sequences in the detection of nerve root compression.ConclusionContinuous thin-slice coronal MR images using 3D FS-nSSFP and 3D T1-GRE sequences are sufficient to evaluate lumbar nerve root compression, and 3D FS-nSSFP is superior to 3D T1-GRE for depiction of lumbar nerve roots.

Anterior chamber configuration in patients with glaucoma: MR gonioscopy evaluation with half-Fourier single-shot RARE sequence and microscopy coil.

The purpose of the study was to determine the accuracy of half-Fourier single-shot rapid acquisition with relaxation enhancement high-spatial-resolution magnetic resonance (MR) imaging performed with a microscopy coil in the diagnosis of narrow anterior chamber angle in patients with glaucoma. Slit-lamp biomicroscopy served as the reference standard. The institutional review board approved this study, and written informed consent was obtained from the 20 recruited patients. There was excellent agreement between MR gonioscopy and slit-lamp biomicroscopy in the classification of anterior chamber angles as narrow or open (kappa = 0.89 [95% confidence interval: 0.69, 1.10]). MR gonioscopy has substantial potential as a technique used to evaluate glaucoma.

Effect of lapatinib on hepatic parenchymal enhancement on gadoxetate disodium (EOB)-enhanced MRI scans.

We present changes seen on hepatobiliary phase (HBP)-gadoxetate disodium (EOB)-enhanced magnetic resonance image of a woman with liver metastases who was treated with lapatinib. After treatment, the HBP images appeared like portal venous phase images. This suggests that lapatinib, an inhibitor of organic anion transporting polypeptide 1B1, one of the substrates of EOB, inhibits EOB uptake by hepatocytes. In patients treated with lapatinib, the ability to diagnose liver tumors on HBP images may be compromised.

Timing of radiological improvement after steroid therapy in patients with autoimmune pancreatitis.

Abstract Objective. We retrospectively studied the timing of radiological improvement after steroid therapy in patients with autoimmune pancreatitis (AIP). Material and methods. Patients with AIP (n = 31) received steroids followed by diagnostic imaging within 1 month. Pancreatic swelling, pancreatic and bile duct features, and apparent diffusion coefficient (ADC) were compared before and after treatment. The period from treatment initiation to evaluation was divided into five phases: early phase (days 3–5), week 1 (days 6 and 7), week 2 (days 8–14), week 3 (days 15–21), and week 4 (days 22–28). Five gastroenterologists evaluated pancreatic swelling and duct features (good/intermediate/no response), and the “good response” rate (response rate) was calculated for each phase. In addition, pancreatic volumes were measured with a 3D workstation before and after treatment, and the percentage change in volume was calculated. ADC values were calculated in 14 patients. Results. The median ratio of pancreatic volume after relative to before treatment was 0.89, 0.79, 0.67, 0.59, and 0.47 for early phase, week 1, week 2, week 3, and week 4, respectively. The response rate of the pancreatic swelling was 37.5%, 57.1%, 83.3%, 100%, and 100%; response rate of the pancreatic duct was 0%, 20%, 75%, 75% and 100%; and response rate of the bile duct was 0%, 66.7%, 83.3%, 100%, and 80%. The ADC increased after treatment in all 14 patients, including the 7 patients evaluated in the early phase. Conclusions. Evaluation of pancreatic swelling and duct features is recommended in week 2 and thereafter. The ADC increased soon after treatment initiation, suggesting its usefulness for evaluating early treatment responses.

Magnetic Resonance Evaluation of Multiple Myeloma at 3.0 Tesla: How Do Bone Marrow Plasma Cell Percentage and Selection of Protocols Affect Lesion Conspicuity?

Purpose To compare various pulse sequences in terms of percent contrast and contrast-to-noise ratio (CNR) for detection of focal multiple myeloma lesions and to assess the dependence of lesion conspicuity on the bone marrow plasma cell percent (BMPC%). Materials and Methods Sagittal T1-weighted FSE, fat-suppressed T2-weighted FSE (FS- T2 FSE), fast STIR and iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) imaging of the lumbar spine were performed (n = 45). Bone marrow (BM)-focal myeloma lesion percent contrast and CNR were calculated. Spearman rank correlation coefficients were obtained between percent contrast, CNR and BMPC%. Percent contrasts and CNRs were compared among the three imaging sequences. Results BM-focal lesion percent contrasts, CNRs and BMPC% showed significant negative correlations in the three fat-suppression techniques. Percent contrast and CNRs were significantly higher for FS- T2 FSE than for STIR (P<0.01, P<0.05, respectively), but no significant differences were found among the three fat-suppression methods in the low tumor load BM group. Conclusion The higher BMPC% was within BM, the less conspicuous the focal lesion was on fat-suppressed MRI. The most effective protocol for detecting focal lesions was FS- T2 FSE. In the high tumor load BM group, no significant differences in lesion conspicuity were identified among the three fat-suppression techniques.

Cutaneous complications after transcatheter arterial treatment for hepatocellular carcinoma via the internal mammary artery: how to avoid this complication.

PurposeTo lower the rate of cutaneous complications after transcatheter arterial treatment for hepatocellular carcinoma (HCC) via the internal mammary artery (IMA) we retrospectively assessed the complications.Materials and methodsWe reviewed cutaneous complications in 14 patients with 18 HCCs who had undergone 17 treatment procedures via the IMA, including selective transcatheter arterial infusion chemotherapy with Lipiodol (Lip-TAI) (n = 3), selective Lip-TAI + transcatheter arterial embolization (TAE) (n = 3), nonselective Lip-TAI (n = 1), nonselective Lip-TAI + TAE (n = 5), and nonselective TAE (n = 5). The filling and nonfilling of subcutaneous vessels with Lipiodol was examined on postoperative computed tomography (CT) scans.ResultsSkin rash (n = 3) and ulceration (n = 1) occurred after 4 of 17 (24%) procedures: two of three selective Lip-TAI procedures and two of five nonselective Lip-TAI + TAE procedures. The doses of chemotherapeutic agents for tumor sizes in selective Lip-TAI procedures were higher than those in selective Lip-TAI + TAE procedures. Cutaneous complications were encountered after two of three procedures with filling but not after any of eight procedures without filling.ConclusionA lower dose of chemotherapeutic agents may be less risky when undertaking a selective procedure via the IMA for HCC. If nonselective, TAE alone may be less risky. Postoperative CT may be helpful for predicting cutaneous complications.

Optimal fast T2-weighted magnetic resonance microscopy imaging of the eye and its clinical application

To compare a half‐Fourier single‐shot rapid acquisition with relaxation enhancement (RARE) sequence with a balanced steady‐state free precession (b‐SSFP) sequence in the evaluation of the eye using magnetic resonance (MR) microscopy imaging and to clarify the usefulness of RARE microscopy imaging in evaluating nonoperative glaucoma patients and patients who have undergone surgery for glaucoma or cataract.

Clinical utility of optimized three-dimensional T1-, T2-, and T2*-weighted sequences in spinal magnetic resonance imaging

This article reviews the clinical utility of 3D magnetic resonance imaging (MRI) sequences optimized for the evaluation of various intraspinal lesions. First, intraspinal tumors with hypervascular components and arteriovenous malformations (AVM) are clearly shown on contrast-enhanced (CE)-3D T1-weighted gradient-echo (GE) sequences with high spatial resolution. Second, dynamic CE-3D time-resolved magnetic resonance angiography (MRA) shows delineated feeding arteries of intraspinal AVM or arteriovenous fistula (AVF), greatly aiding subsequent digital subtraction angiography (DSA). Third, 3D multiecho T2*-weighted GE sequences are used to visualize intraspinal structures and spinal cord lesions and are sensitive to the magnetic susceptibility of intraspinal hemorrhages. Three-dimensional balanced steady-state free precession (SSFP) and multishot 3D balanced non-SSFP sequences produce contiguous thin images with high signal-to-noise ratio (SNR) in short scanning times. Intraspinal cystic lesions and small nerve-root tumors in subarachnoid space can be viewed using 3D balanced SSFP. Spinal cord myelomalacia and cord compression can be evaluated on fat-suppressed multishot 3D balanced non-SSFP. Finally, a 3D T2-weighted fast spin-echo (FSE) sequence with variable flip angle (FA) refocusing pulse improves through-plane spatial resolution over conventional 2D T2-weighted FSE sequences while matching image contrast.