Reconstruction of cervico-thoracic defect with bipedicled deep inferior epigastric perforator free flap following resection of a giant recurrent thyroid tumor: a case report and review of literature.

The bipedicled Deep Inferior Epigastric Perforator (DIEP) flap, originally described and primarily utilized in autologous breast reconstruction for specific cases, has expanded its applications to encompass diverse anatomical regions in recent years. This report presents the case of a 69-year-old woman with a recurrent giant thyroid tumor who underwent surgical resection, resulting in a large cervico-thoracic defect effectively reconstructed using a bipedicled DIEP flap. The patient's postoperative recovery was uneventful, and the follow-up assessments revealed a healthy, well-perfused flap that provided sufficient coverage to critical structures, adequate restoration of the region contour, and enough volume to offset potential adverse effects of subsequent radiation therapy. In addition, this report incorporates a concise literature review highlighting the expanding indications of the bipedicled DIEP flap beyond breast reconstruction, showing the versatility and efficacy of the bipedicled DIEP flap in addressing complex soft-tissue defects in various anatomical areas.

The impact of transsphenoidal surgery on pituitary function in patients with non-functioning macroadenomas.

PURPOSE: Transsphenoidal surgery for non-functioning pituitary adenomas (NFPAs) can alter pituitary function. We assessed the rates of improvement and deterioration of pituitary function by axis and searched for predictive factors of these outcomes. METHODS: We reviewed consecutive medical files from patients having had transsphenoidal surgery for NFPA between 2004 and 2018. Pituitary functions and MRI imaging were analyzed prior and after surgery. The occurrence of recovery and new deficit were documented per axis. Prognostic factors of hormonal recovery and new deficits were searched. RESULTS: Among 137 patients analyzed, median tumor size of the NFPA was 24.8 mm and 58.4% of patients presented visual impairment. Before surgery, 91 patients (67%) had at least one abnormal pituitary axis (hypogonadism: 62.4%; hypothyroidism: 41%, adrenal insufficiency: 30.8%, growth hormone deficiency: 29.9%; increased prolactin: 50.8%). Following surgery, the recovery rate of pituitary deficiency of one axis or more was 46% and the rate of new pituitary deficiency was 10%. Rates of LH-FSH, TSH, ACTH and GH deficiency recovery were 35.7%, 30.4%, 15.4%, and 45.5% respectively. Rates of new LH-FSH, TSH, ACTH and GH deficiencies were 8.3%, 1.6%, 9.2% and 5.1% respectively. Altogether, 24.6% of patients had a global pituitary function improvement and only 7% had pituitary function worsening after surgery. Male patients and patients with hyperprolactinemia upon diagnosis were more likely to experience pituitary function recovery. No prognostic factors for the risk of new deficiencies were identified. CONCLUSION: In a real-life cohort of patients with NFPAs, recovery of hypopituitarism after surgery is more frequent than the occurrence of new deficiencies. Hence, hypopituitarism could be considered a relative indication for surgery in patients with NFPAs.

Comparing dynamic susceptibility contrast perfusion post-processing with different clinically available software among patients affected of a high-grade glioma.

BACKGROUND AND PURPOSE: The main purpose of this retrospective study was to evaluate inter-software variability in patients affected of a high-grade glioma for the post-processing of dynamic susceptibility contrast (DSC1) perfusion imaging in MRI.2 MATERIALS AND METHODS: The included patients were either anaplastic astrocytoma (WHO3 grade III) or glioblastoma (WHO grade IV) located in the cerebral parenchyma. The postprocessing of 54 MRI-DSC imaging from 46 patients using both Intellispace.. (Philips) and Olea.. (Olea Medical) software was performed. The hemodynamic parameter studied was the normalised relative cerebral blood volume corrected for the T1 leakage effect (nrCBVc4). The inter-operator variabilities were also evaluated. RESULTS: Regarding inter-software reproducibility, Cohen...s Kappa from therapeutic follow-up obtained were 0.61, close to the recommended limit (0.60). Subgroups were created to complete the analysis and to evaluate the partial volume effect. Even if necrosis or vascular structures from regions of interest (ROI5) were avoided, results did not improve. ROI of a minimum area of 250...mm2 yielded a Cohen...s Kappa of 0.65. The inter-operator reproducibility on Intellispace and Olea were 0.90 and 0.73 respectively, which is satisfactory. CONCLUSION: The reproducibility between Intellispace and Olea was below recommended threshold in a clinical context. This discrepancy can be explained by the partial volume effect and the models used. ROI with an area of at least 250...mm2 improves this reproducibility and becomes acceptable.

How patient-specific do internal carotid artery inflow rates need to be for computational fluid dynamics of cerebral aneurysms?

BACKGROUND: Computational fluid dynamics (CFD) has become a popular tool for studying 'patient-specific' blood flow dynamics in cerebral aneurysms; however, rarely are the inflow boundary conditions patient-specific. We aimed to test the impact of widespread reliance on generalized inflow rates. METHODS: Internal carotid artery (ICA) flow rates were measured via 2D cine phase-contrast MRI for 24 patients scheduled for endovascular therapy of an ICA aneurysm. CFD models were constructed from 3D rotational angiography, and pulsatile inflow rates imposed as measured by MRI or estimated using an average older-adult ICA flow waveform shape scaled by a cycle-average flow rate (Qavg) derived from the patient's ICA cross-sectional area via an assumed inlet velocity. RESULTS: There was good overall qualitative agreement in the magnitudes and spatial distributions of time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and spectral power index (SPI) using generalized versus patient-specific inflows. Sac-averaged quantities showed moderate to good correlations: R2=0.54 (TAWSS), 0.80 (OSI), and 0.68 (SPI). Using patient-specific Qavg to scale the generalized waveform shape resulted in near-perfect agreement for TAWSS, and reduced bias, but not scatter, for SPI. Patient-specific waveform had an impact only on OSI correlations, which improved to R2=0.93. CONCLUSIONS: Aneurysm CFD demonstrates the ability to stratify cases by nominal hemodynamic 'risk' factors when employing an age- and vascular-territory-specific recipe for generalized inflow rates. Qavg has a greater influence than waveform shape, suggesting some improvement could be achieved by including measurement of patient-specific Qavg into aneurysm imaging protocols.

Manejo de heridas traumáticas de difícil cicatrización con colgajos microvasculares.

OBJECTIVE: Present different flap alternatives when performing microvascular free-flap reconstruction in acute hard-to-heal wounds. METHOD: A retrospective review of patients whose acute hard-to-heal wounds were treated with microvascular free-flap reconstruction. Data on demographics, wound aetiology, diagnostic, previous treatment, free-flap type, free-flap size, complications and follow up were analysed. RESULTS: A total of 20 patients received microvascular free-flap reconstruction. The median age was 39.5 years. Twenty free-flap reconstructions were performed. These included: 3 cross-leg free flap, 1 cross-leg vascular cable bridge flap, 2 fibula osteocutaneous flap, 6 anterolateral thigh (ALT) flap, 3 thoracodorsal artery perforator (TDAP) flap, 3 fasciomyocutaneous flap, and 2 femoral artery fasciocutaneous flap. A patient required microvascular anastomosis due to hematoma; the rest did not present complications during their postoperative. Previous treatment included negative pressure wound therapy (12 patients) and surgical debridement with silver hydrogel dressings (8 patients). CONCLUSION: Hard-to-heal wounds can be unresponsive to traditional wound healing practices or local flaps. They often require free-flap reconstruction, using tissues similar to those compromised. Microvascular techniques can be an effective alternative.

OBJETIVO: El objetivo de este estudio fue presentar diferentes opciones de manejo de heridas de difícil cicatrización utilizando colgajos libres microvasculares. MÉTODO: Se llevó a cabo una revisión retrospectiva de todos los pacientes con heridas traumáticas de difícil cicatrización, a quienes se les realizó reconstrucción con colgajo libre. Se analizaron datos demográficos, etiología de la herida, diagnóstico, tratamiento previo de la herida, tipo de colgajo utilizado, dimensiones del defecto y del colgajo, vasos receptores, complicaciones, y seguimiento. RESULTADOS: En total, 20 pacientes fueron sometidos a reconstrucciones con colgajos libres. La edad promedio fue de 39,5 años. Se realizaron 20 colgajos libres, entre ellos: 3 de piernas cruzadas, 1 de piernas cruzadas con puente vascular, 2 osteocutáneos de peroné, 6 fasciocutáneos anterolateral del muslo, 3 perforantes de la arteria toracodorsal, 3 miocutáneos dorsal ancho, y 2 fasciocutáneos de la perforante de la arteria femoral profunda. Un paciente requirió revisión de anastomosis microvascular debido a un hematoma. El resto de los pacientes no presentó intercurrencias en el postoperatorio. Respecto al tratamiento previo, 12 pacientes recibieron terapia de presión negativa, mientras que 8 tuvieron desbridamientos quirúrgicos con subsecuente aplicación de hidrogel con plata iónica. CONCLUSIÓN: Las heridas de difícil cicatrización no tienen una buena respuesta al tratamiento convencional con curaciones, injertos o colgajos locales, sino que requieren la transferencia de tejidos similares a los que se han perdido. Las técnicas microvasculares pueden ser una alternativa.

Manejo de heridas traumáticas de difícil cicatrización con colgajos microvasculares.

OBJECTIVE: Present different flap alternatives when performing microvascular free-flap reconstruction in acute hard-to-heal wounds. METHOD: A retrospective review of patients whose acute hard-to-heal wounds were treated with microvascular free-flap reconstruction. Data on demographics, wound aetiology, diagnostic, previous treatment, free-flap type, free-flap size, complications and follow up were analysed. RESULTS: A total of 20 patients received microvascular free-flap reconstruction. The median age was 39.5 years. Twenty free-flap reconstructions were performed. These included: 3 cross-leg free flap, 1 cross-leg vascular cable bridge flap, 2 fibula osteocutaneous flap, 6 anterolateral thigh (ALT) flap, 3 thoracodorsal artery perforator (TDAP) flap, 3 fasciomyocutaneous flap, and 2 femoral artery fasciocutaneous flap. A patient required microvascular anastomosis due to hematoma; the rest did not present complications during their postoperative. Previous treatment included negative pressure wound therapy (12 patients) and surgical debridement with silver hydrogel dressings (8 patients). CONCLUSION: Hard-to-heal wounds can be unresponsive to traditional wound healing practices or local flaps. They often require free-flap reconstruction, using tissues similar to those compromised. Microvascular techniques can be an effective alternative.

OBJETIVO: El objetivo de este estudio fue presentar diferentes opciones de manejo de heridas de difícil cicatrización utilizando colgajos libres microvasculares. MÉTODO: Se llevó a cabo una revisión retrospectiva de todos los pacientes con heridas traumáticas de difícil cicatrización, a quienes se les realizó reconstrucción con colgajo libre. Se analizaron datos demográficos, etiología de la herida, diagnóstico, tratamiento previo de la herida, tipo de colgajo utilizado, dimensiones del defecto y del colgajo, vasos receptores, complicaciones, y seguimiento. RESULTADOS: En total, 20 pacientes fueron sometidos a reconstrucciones con colgajos libres. La edad promedio fue de 39,5 años. Se realizaron 20 colgajos libres, entre ellos: 3 de piernas cruzadas, 1 de piernas cruzadas con puente vascular, 2 osteocutáneos de peroné, 6 fasciocutáneos anterolateral del muslo, 3 perforantes de la arteria toracodorsal, 3 miocutáneos dorsal ancho, y 2 fasciocutáneos de la perforante de la arteria femoral profunda. Un paciente requirió revisión de anastomosis microvascular debido a un hematoma. El resto de los pacientes no presentó intercurrencias en el postoperatorio. Respecto al tratamiento previo, 12 pacientes recibieron terapia de presión negativa, mientras que 8 tuvieron desbridamientos quirúrgicos con subsecuente aplicación de hidrogel con plata iónica. CONCLUSIÓN: Las heridas de difícil cicatrización no tienen una buena respuesta al tratamiento convencional con curaciones, injertos o colgajos locales, sino que requieren la transferencia de tejidos similares a los que se han perdido. Las técnicas microvasculares pueden ser una alternativa.

Combined microvascular breast and lymphatic reconstruction with deep inferior epigastric perforator flap and gastroepiploic vascularized lymph node transfer for postmastectomy lymphedema patients.

BACKGROUND: The combination of microvascular breast reconstruction (MBR) and vascularized lymph node transfer (VLNT) in a single-stage procedure is a surgical option for women who desire breast reconstruction and postmastectomy lymphedema surgery. In this study, we present a series of patients who underwent simultaneous lymphatic and MBR with the gastroepiploic VLNT (GE-VLNT) and the deep inferior epigastric perforator (DIEP) flap respectively. METHODS: Between 2018 and 2019, all consecutive patients diagnosed with lymphedema stage IIb-III International Society of Lymphology who opted to pursue simultaneous MBR with DIEP flap and GE-VLNT were included in this study. Patient demographics, comorbidities, prior radiation therapy, operative characteristics, surgical outcomes and complications were collected and analyzed. RESULTS: Six patients underwent simultaneous unilateral MBR with DIEP flap and GE-VLNT. The mean age was 48±10.5 years and mean body mass index was 28.2±4.5 kg/m2. The flap survival rate was 100%. One patient required re-exploration due to venous congestion of the lymph node flap but was successfully salvaged. There was no donor site morbidity at the donor or recipient site for the DIEP flap were seen. The mean circumference reduction rate was 30.0%±5.1% (P<0.001). One patient stage III underwent additional liposuction at 12 months postoperative to improve final results. CONCLUSIONS: The combined use of DIEP flap and GE-VLNT flaps in a single-stage procedure is a safe and reliable surgical option for patients with postmastectomy lymphedema who desire and are suitable for autologous microvascular breast and lymphatic reconstruction.

4D-CT angiography versus 3D-rotational angiography as the imaging modality for computational fluid dynamics of cerebral aneurysms.

BACKGROUND AND PURPOSE: Computational fluid dynamics (CFD) can provide valuable information regarding intracranial hemodynamics. Patient-specific models can be segmented from various imaging modalities, which may influence the geometric output and thus hemodynamic results. This study aims to compare CFD results from aneurysm models segmented from three-dimensional rotational angiography (3D-RA) versus novel four-dimensional CT angiography (4D-CTA). METHODS: Fourteen patients with 16 cerebral aneurysms underwent novel 4D-CTA followed by 3D-RA. Endoluminal geometries were segmented from each modality using an identical workflow, blinded to the other modality, to produce 28 'original' models. Each was then minimally edited a second time to match length of branches, producing 28 additional 'matched' models. CFD simulations were performed using estimated flow rates for 'original' models (representing real-world experience) and patient-specific flow rates from 4D-CTA for 'matched' models (to control for influence of modality alone). RESULTS: Overall, geometric and hemodynamic results were consistent between models segmented from 3D-RA and 4D-CTA, with correlations improving after matching to control for operator-introduced variability. Despite smaller 4D-CTA parent artery diameters (3.49±0.97 mm vs 3.78±0.92 mm for 3D-RA; p=0.005) and sac volumes (157 (37-750 mm3) vs 173 (53-770 mm3) for 3D-RA; p=0.0002), sac averages of time-averaged wall shear stress (TAWSS), oscillatory shear (OSI), and high frequency fluctuations (measured by spectral power index, SPI) were well correlated between 3D-RA and 4D-CTA 'matched' control models (TAWSS, R2=0.91; OSI, R2=0.79; SPI, R2=0.90). CONCLUSIONS: Our study shows that CFD performed using 4D-CTA models produces reliable geometric and hemodynamic information in the intracranial circulation. 4D-CTA may be considered as a follow-up imaging tool for hemodynamic assessment of cerebral aneurysms.

Robust cerebrovascular blood velocity and flow rate estimation from 4D-CTA.

PURPOSE: Blood velocity and flow rate information may be helpful for a wide variety of applications, but it often requires separate acquisitions. The dynamic information combined with the high spatial resolution of four-dimensional computed tomography angiography (4D-CTA) offers the possibility to quantify blood flow simultaneous to vascular anatomy. METHODS: A 4D-CTA clinical protocol with a novel dedicated postprocessing were validated in vitro in a patient-specific model, and tested in a pilot study of six patients. Blood flow was assessed in both internal carotid (ICAs) and vertebral (VAs) arteries by analyzing spatial displacement of contrast agent in the form of time-intensity curves (TICs). Unlike previous approaches, it does not require any a priori assumptions about TIC shape, but rather computes mean velocity and flow rates from the spatial displacement of the TICs along the automatically segmented vessels. RESULTS: In vitro experiments showed good agreement between 4D-CTA and flowmeter measurements under steady and pulsatile flow conditions. In vivo measurements exhibited large interpatient variability of the TIC shapes, from which blood flow rates could nevertheless be successfully measured in all patients and investigated vessels. On average, measured flow rates were 3.2 ± 0.7 ml/s (in ICAs) and 1.3 ± 0.8 ml/s (in VAs) consistent with previous reference standards. Contrary to our novel approach, which considered the full TIC shape, application of previous time-to-peak analyses based on idealized TIC shapes showed limited reliability. CONCLUSIONS: We demonstrate the high potential of 4D-CTA for assessing blood velocity and flow rate in addition to anatomical evaluation. The wide variety of TIC shapes encountered in vivo highlights the importance of an adaptive TIC analysis as proposed in the present work.

A modern multidisciplinary approach to patients suffering from cervical spondylotic myelopathy.

BACKGROUND: The traditional approach to patients suffering from cervical spondylotic myelopathy (CSM) consists of mere assessment of radiological standard magnetic resonance (MR) images and evaluation of surgical indication, depending on clinical symptoms and degree of radiological stenosis. Identification of prognostic factors for surgery remains difficult. Surgery is thought to be able to stop the disease progression, while significant improvements of neurological symptoms are not predictable. METHODS: Authors present a modern approach to patients with CSM, that is comprehensive of clinical, electrophysiological and radiological findings, and that has been developed by a multidisciplinary team of experts (neurosurgeons, neurologists, neuroradiologists). Authors tried to identify the good responders to surgery, as those who really improved symptoms, by performing an integration of these data. This approach has been used in 11 consecutive patients suffering from and operated for CSM at our Institution. The multidisciplinary protocol included the complementary use of electrophysiological (motor and somatosensory evoked potentials), radiological (magnetic resonance, cervical plain and dynamic x-rays), and clinical (modified Japanese Orthopedic Association [mJOA] and Neck Disability Index [NDI] scores, Hirabayashi Recovery Ratio) values. These data were obtained at the preoperative period, and at 3 and 12 months follow-up. We defined as "good responders" those patients having had an improvement of the Hirabayashi Recovery Ratio of 50% and of the NDI of 30%. RESULTS: The mean preoperative mJOA was 12.79 (range 3-17), while the mean mJOA at 3 and 12 months was, respectively, 14.71 and 13.43. However, only the improvement at 3 months was statistically significant, while improvements from the preoperative assessment to 12 months and from 3 to 12 months were not significant. The mean preoperative NDI was 33.57%, while it was 32.43% and 24.36% at 3 and 12 months, respectively. None of these improvements was significant. Concerning response to surgery, we observed 7/11 (63.3%) good responders according to the Hirabayashi Recovery Ratio, and 6/11 (54.5%) good responders according to NDI results. CONCLUSIONS: A modern multidisciplinary approach to patients with CSM is mandatory to investigate the different aspects of the disease. Decompressive surgery was able, in our series, to improve or stabilize clinical symptoms. Further studies are necessary to allow for a proper selection of patients by cumulative analysis of multidisciplinary findings.

Low Frequency Microstimulation Is Locally Excitatory in Patients With Epilepsy.

Deep brain stimulation (DBS) could become a palliative treatment for patients with drug-resistant epilepsy for which surgery cannot be proposed. The objective of this study was to perform microstimulation to measure the effects of DBS in epilepsy locally at the level of a few neurons, with microelectrode recordings, for the first time in patients with epilepsy. Microelectrode recordings were performed before, during and after microstimulation in nine patients with refractory epilepsy. Neuronal spikes were successfully extracted from multi-unit recordings with clustering in six out of seven patients during hippocampal and in one out of two patients during cortical dysplasia microstimulation (1 Hz, charge-balanced biphasic waveform, 60 µs/ph, 25 µA). The firing rates increased in four out of the six periods of microstimulation that could be analyzed. The firing rates were found higher than before microstimulation in all eight periods with increases reaching significance in six out of eight periods. Low-frequency microstimulation was hence sufficient to induce neuronal excitation lasting beyond the stimulation period. No inhibition was observed. This report presents the first evidence that microstimulation performed in epileptic patients produced locally neuronal excitation. Hence neuronal excitation is shown here as the local mechanism of action of DBS. This local excitation is in agreement with epileptogenic effects of low-frequency hippocampal macrostimulation.

Yield of MRI, high-density electric source imaging (HD-ESI), SPECT and PET in epilepsy surgery candidates.

OBJECTIVE: Preoperative workup aims at localizing the epileptogenic focus to achieve postoperative seizure-freedom. We studied the predictive value of non-invasive techniques, i.e. structural magnetic resonance imaging [MRI], high-density electric source imaging [HD-ESI] and metabolic imaging (positron emission tomography [PET]; single-photon emission computed tomography [SPECT]), in surgically treated patients. METHODS: A prospective study of 190 epileptic operated patients, with >12 months follow-up and analyzed with state-of-the-art algorithms. 58 patients underwent all techniques. We computed sensitivity, specificity, predictive value and diagnostic odds ratio (OR) in relation to postoperative outcome. RESULTS: Of 190 patients, 148 (77.9%) were seizure-free at follow-up. Resection of the epileptogenic focus was associated with favorable postsurgical outcome (p<0.05). Among 58 patients who underwent all tests, only MRI and HD-ESI were favorable outcome predictors (MRI: OR 10.9, p=0.004; HD-ESI: OR 13.1, p=0.004). Patients with concordant structural MRI and HD-ESI results had 92.3% (24/26) probability of favorable outcome. When both results were negative, probability was 0% (0/5); and when they disagreed, it was 63.0% (17/27). CONCLUSIONS: Combination of MRI and HD-ESI offered the highest predictive value for postoperative seizure-freedom. SIGNIFICANCE: This finding highlights the added value of HD-ESI in the presurgical workup, in particular in combination with an informative MRI.

All-in-one interictal presurgical imaging in patients with epilepsy: single-session EEG/PET/(f)MRI.

PURPOSE: In patients with pharmacoresistant focal epilepsy, resection of the epileptic focus can lead to freedom from seizures or significant improvement in well-selected candidates. Localization of the epileptic focus with multimodal concordance is crucial for a good postoperative outcome. Beyond the detection of epileptogenic lesions on structural MRI and focal hypometabolism on FDG PET, EEG-based Electric Source Imaging (ESI) and simultaneous EEG and functional MRI (EEG-fMRI) are increasingly applied for mapping epileptic activity. We here report presurgical multimodal interictal imaging using a hybrid PET/MR scanner for single-session FDG PET, MRI, EEG-fMRI and ESI. METHODS: This quadrimodal imaging procedure was performed in a single session in 12 patients using a high-density (256 electrodes) MR-compatible EEG system and a hybrid PET/MR scanner. EEG was used to exclude subclinical seizures during uptake of the PET tracer, to compute ESI on interictal epileptiform discharges and to guide fMRI analysis for mapping haemodynamic changes correlated with interictal epileptiform activity. RESULTS: The whole multimodal recording was performed in less than 2 hours with good patient comfort and data quality. Clinically contributory examinations with at least two modalities were obtained in nine patients and with all modalities in five patients. CONCLUSION: This single-session quadrimodal imaging procedure provided reliable and contributory interictal clinical data. This procedure avoids multiple scanning sessions and is associated with less radiation exposure than PET-CT. Moreover, it guarantees the same medication level and medical condition for all modalities. The procedure improves workflow and could reduce the duration and cost of presurgical epilepsy evaluations.

Look for the nerves! MR neurography adds essential diagnostic value to routine MRI in pediatric practice: a pictorial overview.

PURPOSE: This study aimed to assess the feasibility of magnetic resonance (MR) neurography in children, and the potential roles of diffusion-weighted imaging (DWI) and fiber-tracking (FT) techniques. METHODS: Five pediatric patients (age range: 6-12 years) underwent magnetic resonance imaging (MRI) for various clinical indications: neurogenic bladder (case 1); persistent hand pain following minor trauma (case 2); progressive atrophy of the lower left extremity muscles (case 3); bilateral hip pain (case 4); and palpable left supraclavicular mass (case 5). All studies were performed using a 1.5-T Avanto MRI scanner (Siemens, Erlangen, Germany). The protocol included 3D T2-weighted STIR and SPACE imaging, T1-weighted fat-saturation post-gadolinium imaging and diffusion tensor imaging (DTI) with tractography. ADC (N×10(-3) mm(2)/s) and FA values were calculated from regions of interest (ROIs) centered on the nerves. Nerve-fiber tracks were calculated using a fourth-order Runge-Kutta algorithm (NeuroD software). RESULTS: MR neurography allowed satisfactory visualization of all neural structures, and FA and ADC measurements were feasible. The final diagnoses were Tarlov cysts, median-nerve compression, sciatic perineurioma, Charcot-Marie-Tooth disease and plexiform neurofibroma in a patient with NF-1. DISCUSSION: FA and ADC measurements are of little value because of the lack of normal reference values. Nerve-fiber tractography (FT) may be of value in the characterization of tumor pathology, and is also helpful in the planning of surgical treatments. CONCLUSION: MR neurography is feasible in pediatric patients. However, a considerable amount of work has yet to be done to establish its role in the clinical management of the wide range of peripheral nerve diseases.

MRI with fibre tracking in Cogan congenital oculomotor apraxia.

BACKGROUND: Congenital ocular motor apraxia (COMA) occasionally shares with Joubert syndrome (JS) and related disorders (JSRDs) a peculiar malformation, the 'molar tooth sign' (MTS). In JSRDs, the absence of superior cerebellar peduncles (SCP) decussation is reported. OBJECTIVE: To investigate whether COMA demonstrates similar abnormal axonal pathways. MATERIALS AND METHODS: Eight healthy age-matched controls, three children with clinical COMA and one child with clinical JSRD underwent examination with a 1.5-T MRI scanner. Diffusion-weighted imaging (DWI), colour-coded fractional anisotropy maps and three-dimensional diffusion tensor imaging (DTI) tractography of the cerebellorubral network were analyzed. RESULTS: On DTI cartography, the 'red dot' originally supposed to represent the SCP decussation in the midbrain was present in controls as well in those with COMA but absent in the single case with JS. In none of the subjects including controls was 3-D FT able to depict the SCP decussation. When seeded, the red dot resulted in the ventral tegmental decussation (VTD). It was normal in controls and in patients with COMA but was absent in our single patient with JSRD. MTS was identified in alla patients with COMA and in the patient with JSRD. CONCLUSION: MTS can be present in both COMA and JSRD but the underlying anatomy depicted by fibre tracking is distinct. The main difference is the integrity of the VTD in COMA.

MRI neurography and diffusion tensor imaging of a sciatic perineuroma in a child.

Perineuroma, rare in children, presents as a painless mononeuropathy of a major nerve trunk. Resection of the lesion with end-to-end sural nerve grafting appears to be the treatment of choice. This technique is not recommended if the unhealthy segment of nerve is too long or if spinal roots are involved. However, in children, reports of direct MR evaluation of nerve trunks and of the exiting nerve roots are limited. We report a 7-year-old girl with an intramural sciatic nerve perineuroma in whom the diagnosis was made by MRI and confirmed by biopsy. The MR protocol combining 3-D T2-W STIR SPACE, fat-saturated gadolinium-enhanced T1-W images, and diffusion tensor imaging with tractography was a valuable tool for depicting peripheral nerve and roots in order to plan surgical treatment.