Liver impalement with an antique African iron barbed spear. A case report.

Impalement injuries happen when an object penetrates a body cavity or organ and remains in situ. We present a case of a 35-year-old fisherman whose act of violence resulted in the lodging of an antique iron spear in segment V of the liver, which was then referred to our institution on the day after the accident. Despite the challenges posed by patient transfer, diagnosis, resuscitation, and, most importantly, handling in the operating room, the object was successfully removed via hepatotomy, and the patient is now in good health. Impalement by an ancient African iron spear, repurposed as a fishing tool in modern times, remains undocumented in the literature, necessitating reporting and a call for further research by the medical community into managing impalement injuries of varying severity.

Adult with concurrent mesenteric cyst and acute appendicitis: a case report.

Mesenteric cysts are uncommon intra-abdominal lesions that account for only one in every 100 000 adult hospitalizations. Their diagnosis is based on a comprehensive clinical examination as well as radiological modalities such as ultrasonography and computed tomography (CT) scans, and it is usually a clinical challenge because of non-specific symptoms. We present our first case of a 51-year-old man with a simple mesenteric cyst accompanying acute appendicitis diagnosed by CT scan of the abdomen and treated by exploratory laparotomy, complete enucleation of the cyst and appendectomy with a 10 month follow-up without complications or recurrence. This type of presentation has not been thoroughly investigated, with only two children reported during our literature review. Even if there is a high level of suspicion, a CT scan is required for confirmation.

Our first Pfannenstiel incisional hernia. A case report.

The incidence of the Pfannenstiel incisional hernia (IH) is the lowest of all IHs, it can occur due to patient-related factors or faulty technique in closure of the deeper layer. The use of prosthetic mesh repair is heralding a new era of tension-free herniorrhaphy, while the optimal location for its implantation remains controversial. As a result, no strategy or technique has become the gold standard for its repair. We report our first experience with an IH through Pfannenstiel in a 49-year-old obese female patient. Inlay polypropylene open mesh repair was performed. As the only complication, the patient presented with a seroma in the wound, which was aspirated, and she is currently asymptomatic with outpatient consultation follow-up. Pfannenstiel IHs have received minimal attention on the optimal surgical approach and postoperative results, making this case a good starting point for future studies.

Cervicofacial necrotizing fasciitis after topical application of herbal medicine.

Cervical necrotizing fasciitis represents an aggressive form of deep neck space infection with a high mortality rate. The origin is generally odontogenic, in most cases, resulting from a dental abscess. A series of three cases developed after local application of herbal medicine in patients with no co-morbidities and with a history of a toothache in the lower quadrants for >2 weeks is presented. All patients were managed with antibiotics, extraction of offending tooth and serial wound debridement. Two patients recovered with a resultant skin defect on the neck and one died due to multiple organ failure. This case series demonstrated that early diagnosis, prompt surgical intervention and appropriate medical treatment are very important to increase patient survival. Late report to hospital because of financial constraints and over-reliance on herbal preparation could lead to the development of serious complication in patients with dental infections and could even lead to death of the patient.

Acute traumatic abdominal wall hernia-value of the physical examination: case report.

Acute traumatic abdominal wall hernia (TAWH) is a rare type of hernia that occurs after a low or high velocity impact of the abdominal wall against a blunt object with few cases reported. Perforations of the hollow viscera commonly follow abdominal trauma and likely require surgery for hemorrhage and sepsis source control. We report a case where a high velocity impact of the abdominal wall against the stump of a felled tree caused a TAWH with concomitant gastric perforation in a 20-year-old male patient who required exploratory laparotomy with primary repair of the stomach and fascia. The physical examination findings without previous history of abdominal hernia and pneumoperitoneum in the chest X-ray made suspect our diagnosis and it was confirmed intraoperatively. At 3 months postoperatively the patient has a strong abdominal wall. It is imperative to emphasize the importance of the physical examination goal of not losing diagnosis of TAWH.

Giant intraparietal inguinal hernia misdiagnosed as spigelian hernia in an old woman.

Intraparietal inguinal hernias are a rare variant of inguinal hernia in which the hernia sac lies between the layers of the abdominal muscles. Intraparietal inguinal hernias mimic Spigelian hernias clinically; the diagnosis presents superior difficulties than its treatment. We report a case of a giant intraparietal hernia misdiagnosed as a Spigelian hernia clinically. The patient was 83 years old woman presented with complain of a large swelling over right abdomen for around 25 years. The patient had a huge mass of 25 x 30 cm occupying right flank, right lumbar region extending up to the umbilicus and inguinal region, partially reducible with gurgling sounds. Surgery started with transversal incision over the mass, it was found to be an interstitial variety of intraparietal inguinal hernia with a long viable segment of the small bowel with their mesentery as content of the sac. Hernioplasty with a polypropylene mesh was achieved satisfactorily. The patient was discharged on third postoperative day without complications. It is challenging to diagnose intraparietal hernias preoperatively; intraoperative findings defined its definitive diagnosis and its surgical technique.

Large intra-abdominal mucinous cystic adenoma: is it of ovarian or mesenteric origin.

A 54-year-old female presented with a six year history of increasing abdominal swelling and discomfort and two months of intermittent constipation and difficulty with micturition. She was referred from the gynecological service having been investigated for a pelvic pathology without any positive findings. Her medical history was otherwise unremarkable. Physical examination revealed a non-tender intra-abdominal mass extending from epigastrium to the pelvis with a smooth surface. A large intra-abdominal multi-loculated cyst, separate from the ovaries, was seen on imaging. At laparotomy, the cystic tumour was discovered to arise from the mesentery of the terminal ileum and was resected en bloc. Histopathology revealed the tumour to be a benign mucinous cystadenoma, possibly of ovarian origin. This report aims to raise awareness of the difficulty of distinguishing ovarian from extra-ovarian mucinous cystadenomas on histopathological examination alone.

Diffusion tensor imaging and tractography for preoperative assessment of benign peripheral nerve sheath tumors.

PURPOSE: To evaluate the diagnostic value of fiber tractography and diffusivity analysis generated from 3D diffusion-weighted (DW) sequences for preoperative assessment of benign peripheral nerve sheath tumors. METHOD: MR imaging at 3 T was performed in 22 patients (mean age 41.9 ±â€¯17.1y, 13 women) with histologically confirmed schwannomas (N = 18) and histologically confirmed neurofibromas (N = 11), including a 3D DW turbo spin echo sequence with fat suppression. Diffusion tensor parameters were computed and fiber tracks were determined. Evaluation was performed by two radiologists and one orthopedic surgeon blinded for final diagnosis. Mean diffusivity was computed to allow further assessment of tumor microstructure. Preoperative fascicle visualization was graded, fascicles were categorized regarding anatomical location and amount of fascicles surrounding the tumor. The agreement of imaging findings with intraoperative findings was assessed. RESULTS: On 78.3 % of the DTI images, the fascicle visualization was rated as good or very good. Tractography differences were observed in schwannomas and neurofibromas, showing schwannomas to be significantly more often located eccentrically to the nerve (94.8 %) than neurofibromas (0 %, P < 0.01). Fascicles were significantly more often continuous (87.5 %) in schwannomas, while in neurofibromas, none of the tracks was graded to be continuous (0 %, P = 0.014). A substantial agreement between fiber tracking and surgical anatomy was found regarding the fascicle courses surrounding the tumor (κ = 0.78). Mean diffusivity of schwannomas (1.5 ±â€¯0.2 × 10-3 mm2/s) was significantly lower than in neurofibromas (1.8 ±â€¯0.2 × 10-3 mm2/s; P < 0.001). The Youden index showed an optimal cutoff at 1.7 × 10-3 mm2/s (sensitivity, 0.91; specificity, 0.78; J = 0.69). CONCLUSIONS: Preoperative diffusion tensor imaging allowed to accurately differentiate between schwannomas and neurofibromas and to describe their location in relation to the nerve fascicles for preoperative planning.

Magnetic resonance neurography of the lumbosacral plexus at 3 Tesla - CSF-suppressed imaging with submillimeter resolution by a three-dimensional turbo spin echo sequence.

PURPOSE: To investigate magnetic resonance neurography (MRN) of the lumbosacral plexus (LSP) with cerebrospinal fluid (CSF) suppression by using submillimeter resolution for three-dimensional (3D) turbo spin echo (TSE) imaging. MATERIALS AND METHODS: Using extended phase graph (EPG) analysis, the signal response of CSF was simulated considering dephasing from coherent motion for frequency-encoding voxel sizes ranging from 0.3 to 1.3 mm and for CSF velocities ranging from 0 to 4 cm/s. In-vivo MRN included 3D TSE data with frequency encoding parallel to the feet/head axis from 15 healthy adults (mean age: 28.5 ± 3.8 years, 5 females; acquisition voxel size: 2 × 2 × 2 mm3) and 16 pediatric patients (mean age: 6.7 ± 4.1 years, 7 females; acquisition voxel size: 0.7 × 0.7 × 1.4 mm3) acquired at 3 Tesla. Five of the adults were scanned repetitively with changing acquisition voxel sizes (1 × 2 × 2 mm3, 0.7 × 2× 2 mm3, and 0.5 × 2 × 2 mm3). Measurements of the bilateral ganglion of the L5 nerve root, averaged between sides, as well as the CSF in the thecal sac were obtained for all included subjects and compared between adults and pediatric patients and between voxel sizes, using a CSF-to-nerve signal ratio (CSFNR). RESULTS: According to simulations, the CSF signal is reduced along the echo train for moving spins. Specifically, it can be reduced by over 90% compared to the maximum simulated signal for flow velocities above 2 cm/s, and could be most effectively suppressed by considering a frequency-encoding voxel size of 0.8 mm or less. For in-vivo measurements, mean CSFNR was 1.52 ± 0.22 for adults and 0.10 ± 0.03 for pediatric patients (p < .0001). Differences in CSFNR were significant between measurements using a voxel size of 2 × 2 × 2 mm3 and measurements in data with reduced voxel sizes (p ≤ .0012), with submillimeter resolution (particularly 0.5 × 2 × 2 mm3) providing highest CSF suppression. CONCLUSIONS: Applying frequency-encoding voxel sizes in submillimeter range for 3D TSE imaging with frequency encoding parallel to the feet/head axis may considerably improve MRN of LSP pathology in adults in the future because of favorable CSF suppression.

T2 mapping of the distal sciatic nerve in healthy subjects and patients suffering from lumbar disc herniation with nerve compression.

OBJECTIVE: To measure T2 values for magnetic resonance neurography (MRN) of the healthy distal sciatic nerve and compare those to T2 changes in patients with nerve compression. MATERIALS AND METHODS: Twenty-one healthy subjects and five patients with sciatica due to disc herniation underwent MRN using a T2-prepared turbo spin echo (TSE) sequence of the distal sciatic nerve bilaterally. Six and one of those healthy subjects further underwent a commonly used multi-echo spin-echo (MESE) sequence and magnetic resonance spectroscopy (MRS), respectively. RESULTS: T2 values derived from the T2-prepared TSE sequence were 44.6 ± 3.0 ms (left) and 44.5 ± 2.6 ms (right) in healthy subjects and showed good inter-reader reliability. In patients, T2 values of 61.5 ± 6.2 ms (affected side) versus 43.3 ± 2.4 ms (unaffected side) were obtained. T2 values of MRS were in good agreement with measurements from the T2-prepared TSE, but not with those of the MESE sequence. DISCUSSION: A T2-prepared TSE sequence enables precise determination of T2 values of the distal sciatic nerve in agreement with MRS. A MESE sequence tends to overestimate nerve T2 compared to T2 from MRS due to the influence of residual fat on T2 quantification. Our approach may enable to quantitatively assess direct nerve affection related to nerve compression.

Recent Advances in Pediatric Brain, Spine, and Neuromuscular Magnetic Resonance Imaging Techniques.

Magnetic resonance imaging (MRI) is a powerful radiologic tool with the ability to generate a variety of proton-based signal contrast from tissues. Owing to this immense flexibility in signal generation, new MRI techniques are constantly being developed, tested, and optimized for clinical utility. In addition, the safe and nonionizing nature of MRI makes it a suitable modality for imaging in children. In this review article, we summarize a few of the most popular advances in MRI techniques in recent years. In particular, we highlight how these new developments have affected brain, spine, and neuromuscular imaging and focus on their applications in pediatric patients. In the first part of the review, we discuss new approaches such as multiphase and multidelay arterial spin labeling for quantitative perfusion and angiography of the brain, amide proton transfer MRI of the brain, MRI of brachial plexus and lumbar plexus nerves (i.e., neurography), and T2 mapping and fat characterization in neuromuscular diseases. In the second part of the review, we focus on describing new data acquisition strategies in accelerated MRI aimed collectively at reducing the scan time, including simultaneous multislice imaging, compressed sensing, synthetic MRI, and magnetic resonance fingerprinting. In discussing the aforementioned, the review also summarizes the advantages and disadvantages of each method and their current state of commercial availability from MRI vendors.

Paraspinal Muscle DTI Metrics Predict Muscle Strength.

BACKGROUND: The paraspinal muscles play an important role in the onset and progression of lower back pain. It would be of clinical interest to identify imaging biomarkers of the paraspinal musculature that are related to muscle function and strength. Diffusion tensor imaging (DTI) enables the microstructural examination of muscle tissue and its pathological changes. PURPOSE: To investigate associations of DTI parameters of the lumbar paraspinal muscles with isometric strength measurements in healthy volunteers. STUDY TYPE: Prospective. SUBJECTS: Twenty-one healthy subjects (12 male, 9 female; age = 30.1 ± 5.6 years; body mass index [BMI] = 27.5 ± 2.6 kg/m2 ) were recruited. FIELD STRENGTH/SEQUENCE: 3 T/single-shot echo planar imaging (ss-EPI) DTI in 24 directions; six-echo 3D spoiled gradient echo sequence for chemical shift encoding-based water-fat separation. ASSESSMENT: Paraspinal muscles at the lumbar spine were examined. Erector spinae muscles were segmented bilaterally; cross-sectional area (CSA), proton density fat fraction (PDFF), and DTI parameters were calculated. Muscle flexion and extension maximum isometric torque values [Nm] at the back were measured with an isokinetic dynamometer and the ratio of extension to flexion strength (E/F) calculated. STATISTICAL TESTS: Pearson correlation coefficients; multivariate regression models. RESULTS: Significant positive correlations were found between the ratio of extension to flexion (E/F) strength and mean diffusivity (MD) (P = 0.019), RD (P = 0.02) and the eigenvalues (λ1: P = 0.026, λ2: P = 0.033, λ3: P = 0.014). In multivariate regression models λ3 of the erector spinae muscle λ3 and gender remained statistically significant predictors of E/F (R2adj = 0.42, P = 0.003). DATA CONCLUSION: DTI allowed the identification of muscle microstructure differences related to back muscle function that were not reflected by CSA and PDFF. DTI may potentially track subtle changes of back muscle tissue composition. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:816-823.

T2 mapping of lumbosacral nerves in patients suffering from unilateral radicular pain due to degenerative disc disease.

OBJECTIVELumbosacral radicular syndrome (LRS) is a very common condition, often requiring diagnostic imaging with the aim of elucidating a structural cause when symptoms are longer lasting. However, findings on conventional anatomical MRI do not necessarily correlate with clinical symptoms, and it is primarily performed for the qualitative evaluation of surrounding compressive structures, such as herniated discs, instead of to evaluate the nerves directly. The present study investigated the performance of quantitative imaging by using magnetic resonance neurography (MRN) in patients with LRS.METHODSEighteen patients (55.6% males, mean age 64.4 ± 10.2 years), with strict unilateral LRS matching at least one dermatome and suspected disc herniation, underwent high-resolution 3-T MRN using T2 mapping. On T2 maps, the presumably affected and contralateral unaffected nerves were identified; subsequent regions of interest (ROIs) were placed at preganglionic, ganglionic, and postganglionic sites; and T2 values were extracted. Patients then underwent an epidural steroid injection (ESI) with local anesthetic agents at the site of suspected nerve affection. T2 values of the affected nerves were compared against the contralateral nerves. Furthermore, receiver operating characteristics were calculated based on the measured T2 values and the responsiveness to ESI.RESULTSThe mean T2 value was 77.3 ± 1.9 msec for affected nerves and 74.8 ± 1.4 msec for contralateral nerves (p < 0.0001). In relation to ESI performed at the site of suspected nerve affection, MRN with T2 mapping had a sensitivity/specificity of 76.9%/60.0% and a positive/negative predictive value of 83.3%/50.0%. Signal alterations in affected nerves according to qualitative visual inspection were present in only 22.2% of patients.CONCLUSIONSAs one of the first of its kind, this study revealed elevated T2 values in patients suffering from LRS. T2 values of lumbosacral nerves might be used as more objective parameters to directly detect nerve affection in such patients.

High Isotropic Resolution T2 Mapping of the Lumbosacral Plexus with T2-Prepared 3D Turbo Spin Echo.

PURPOSE: Isotropic high-resolution three-dimensional (3D) magnetic resonance neurography (MRN) is increasingly used to depict even small and highly oblique nerves of the lumbosacral plexus (LSP). The present study introduces a T2 mapping sequence (T2-prepared 3D turbo spin echo) that is B1-insensitive and enables quantitative assessment of LSP nerves. METHODS: In this study 15 healthy subjects (mean age 28.5 ± 3.8 years) underwent 3 T MRN of the LSP area three times. The T2 values were calculated offline on a voxel-by-voxel basis and measured at three segments (preganglionic, ganglionic, postganglionic) of three LSP nerves (S1, L5, L4) by two independent investigators (experienced and novice). Normative data for the different nerves were extracted and intraclass correlation coefficients (ICCs) were calculated to assess reproducibility and interobserver reliability of T2 measurements. RESULTS: The T2 mapping showed excellent reproducibility with ICCs ranging between 0.99 (S1 preganglionic) and 0.89 (L5 postganglionic). Interobserver reliability was less robust with ICCs ranging between 0.78 (S1 preganglionic) and 0.44 (L5 postganglionic) for S1 and L5. A mean T2 value of 74.6 ± 4.7 ms was registered for preganglionic segments, 84.7 ± 4.1 ms for ganglionic and 65.4 ± 2.5 ms for postganglionic segments, respectively. There was a statistically significant variation of T2 values across the nerve (preganglionic vs ganglionic vs postganglionic) for S1, L5, and L4. CONCLUSION: Our approach enables isotropic high-resolution and B1-insensitive T2 mapping of LSP nerves with excellent reproducibility. It might reflect a robust and clinically useful method for future diagnostics of LSP pathologies.

Improved Brachial Plexus Visualization Using an Adiabatic iMSDE-Prepared STIR 3D TSE.

PURPOSE: The close proximity of blood vessels to the brachial plexus nerves can confound nerve visualization in conventional fat-suppressed 3D T2-weighted sequences. Vessel suppression can be accomplished by means of motion-sensitizing preparation. The aim of this study was to qualitatively and semi-quantitatively evaluate short tau inversion recovery (STIR) 3D turbo spin echo (TSE) in conjunction with an adiabatic T2 preparation incorporating motion sensitization for magnetic resonance neurography (MRN) of the brachial plexus in a clinical routine setting. METHODS: The MRN of the brachial plexus was performed in 22 patients (age 45.5 ± 20.3 years) with different clinical implications using the proposed improved motion-sensitized driven equilibrium (iMSDE) STIR 3D TSE and the STIR 3D TSE. Images were evaluated regarding image quality, overall artifacts, artifacts caused by vessel signal, signal homogeneity, visibility of small nerves and signal contrast. Furthermore, signal-to-noise ratios (aSNR), nerve muscle contrast to noise ratios (aNMCNR) and nerve vessel contrast to noise ratios (aNVCNR) were calculated and compared. RESULTS: The incorporation of motion sensitization in the T2 preparation resulted in robust blood suppression across subjects, leading to significantly higher aNVCNRs (p < 0.001) and aNMCNRs (p < 0.05), increased conspicuousness of the nerves, better vessel suppression and image quality and less artifacts compared with STIR 3D TSE (p < 0.001). CONCLUSION: The incorporation of the proposed adiabatic iMSDE-based motion sensitization was shown to provide robust blood suppression of vessels in close proximity to brachial plexus nerves. The use of STIR iMSDE 3D TSE can be considered for clinical MRN examinations of the brachial plexus.

T2-Weighted Dixon Turbo Spin Echo for Accelerated Simultaneous Grading of Whole-Body Skeletal Muscle Fat Infiltration and Edema in Patients With Neuromuscular Diseases.

OBJECTIVE: The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T1-weighted and fat-suppressed T2-weighted sequences. T2-weighted Dixon turbo spin echo (TSE) enables the generation of T2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects. METHODS: Whole-body magnetic resonance imaging was performed including T1-weighted Dixon fast field echo, T2-weighted short-tau inversion recovery, and T2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's κ coefficients were calculated. RESULTS: The ratings of fatty infiltration showed high intermethod and high interrater agreement (T1-weighted Dixon fast field echo vs T2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T2-weighted short-tau inversion recovery vs T2-weighted Dixon TSE water image). CONCLUSIONS: T2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs.

Isotropic resolution diffusion tensor imaging of lumbosacral and sciatic nerves using a phase-corrected diffusion-prepared 3D turbo spin echo.

PURPOSE: To perform in vivo isotropic-resolution diffusion tensor imaging (DTI) of lumbosacral and sciatic nerves with a phase-navigated diffusion-prepared (DP) 3D turbo spin echo (TSE) acquisition and modified reconstruction incorporating intershot phase-error correction and to investigate the improvement on image quality and diffusion quantification with the proposed phase correction. METHODS: Phase-navigated DP 3D TSE included magnitude stabilizers to minimize motion and eddy-current effects on the signal magnitude. Phase navigation of motion-induced phase errors was introduced before readout in 3D TSE. DTI of lower back nerves was performed in vivo using 3D TSE and single-shot echo planar imaging (ss-EPI) in 13 subjects. Diffusion data were phase-corrected per kz plane with respect to T2 -weighted data. The effects of motion-induced phase errors on DTI quantification was assessed for 3D TSE and compared with ss-EPI. RESULTS: Non-phase-corrected 3D TSE resulted in artifacts in diffusion-weighted images and overestimated DTI parameters in the sciatic nerve (mean diffusivity [MD] = 2.06 ± 0.45). Phase correction of 3D TSE DTI data resulted in reductions in all DTI parameters (MD = 1.73 ± 0.26) of statistical significance (P ≤ 0.001) and in closer agreement with ss-EPI DTI parameters (MD = 1.62 ± 0.21). CONCLUSION: DP 3D TSE with phase correction allows distortion-free isotropic diffusion imaging of lower back nerves with robustness to motion-induced artifacts and DTI quantification errors. Magn Reson Med 80:609-618, 2018. © 2018 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

MRI biomarkers of proximal nerve injury in CIDP.

Objective: To evaluate the utility of nerve diffusion tensor imaging (DTI), nerve cross-sectional area, and muscle magnetic resonance imaging (MRI) multiecho Dixon for assessing proximal nerve injury in chronic inflammatory demyelinating polyneuropathy (CIDP). Methods: In this prospective observational cohort study, 11 patients with CIDP and 11 healthy controls underwent a multiparametric MRI protocol with DTI of the sciatic nerve and assessment of muscle proton-density fat fraction of the biceps femoris and the quadriceps femoris muscles by multiecho Dixon MRI. Patients were longitudinally evaluated by MRI, clinical examination, and nerve conduction studies at baseline and after 6 months. Results: In sciatic nerves of CIDP patients, mean cross-sectional area was significantly higher and fractional anisotropy value was significantly lower, compared to controls. In contrast, muscle proton-density fat fraction was significantly higher in thigh muscles of patients with CIDP, compared to controls. MRI parameters showed high reproducibility at baseline and 6 months. Interpretation: Advanced MRI parameters demonstrate subclinical proximal nerve damage and intramuscular fat accumulation in CIDP. Data suggest DTI and multiecho Dixon MRI might be useful in estimating axonal damage and neurogenic muscle changes in CIDP.

Orthogonally combined motion- and diffusion-sensitized driven equilibrium (OC-MDSDE) preparation for vessel signal suppression in 3D turbo spin echo imaging of peripheral nerves in the extremities.

PURPOSE: To design a preparation module for vessel signal suppression in MR neurography of the extremities, which causes minimal attenuation of nerve signal and is highly insensitive to eddy currents and motion. METHODS: The orthogonally combined motion- and diffusion-sensitized driven equilibrium (OC-MDSDE) preparation was proposed, based on the improved motion- and diffusion-sensitized driven equilibrium methods (iMSDE and FC-DSDE, respectively), with specific gradient design and orientation. OC-MDSDE was desensitized against eddy currents using appropriately designed gradient prepulses. The motion sensitivity and vessel signal suppression capability of OC-MDSDE and its components were assessed in vivo in the knee using 3D turbo spin echo (TSE). Nerve-to-vessel signal ratios were measured for iMSDE and OC-MDSDE in 7 subjects. RESULTS: iMSDE was shown to be highly sensitive to motion with increasing flow sensitization. FC-DSDE showed robustness against motion, but resulted in strong nerve signal loss with diffusion gradients oriented parallel to the nerve. OC-MDSDE showed superior vessel suppression compared to iMSDE and FC-DSDE and maintained high nerve signal. Mean nerve-to-vessel signal ratios in 7 subjects were 0.40 ± 0.17 for iMSDE and 0.63 ± 0.37 for OC-MDSDE. CONCLUSION: OC-MDSDE combined with 3D TSE in the extremities allows high-near-isotropic-resolution imaging of peripheral nerves with reduced vessel contamination and high nerve signal. Magn Reson Med 79:407-415, 2018. © 2017 Wiley Periodicals, Inc.

Analysis of phase error effects in multishot diffusion-prepared turbo spin echo imaging.

BACKGROUND: To characterize the effect of phase errors on the magnitude and the phase of the diffusion-weighted (DW) signal acquired with diffusion-prepared turbo spin echo (dprep-TSE) sequences. METHODS: Motion and eddy currents were identified as the main sources of phase errors. An analytical expression for the effect of phase errors on the acquired signal was derived and verified using Bloch simulations, phantom, and in vivo experiments. RESULTS: Simulations and experiments showed that phase errors during the diffusion preparation cause both magnitude and phase modulation on the acquired data. When motion-induced phase error (MiPe) is accounted for (e.g., with motion-compensated diffusion encoding), the signal magnitude modulation due to the leftover eddy-current-induced phase error cannot be eliminated by the conventional phase cycling and sum-of-squares (SOS) method. By employing magnitude stabilizers, the phase-error-induced magnitude modulation, regardless of its cause, was removed but the phase modulation remained. The in vivo comparison between pulsed gradient and flow-compensated diffusion preparations showed that MiPe needed to be addressed in multi-shot dprep-TSE acquisitions employing magnitude stabilizers. CONCLUSIONS: A comprehensive analysis of phase errors in dprep-TSE sequences showed that magnitude stabilizers are mandatory in removing the phase error induced magnitude modulation. Additionally, when multi-shot dprep-TSE is employed the inconsistent signal phase modulation across shots has to be resolved before shot-combination is performed.