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AIM: One of the most important microvasculatures' geometrical variables is number of pores per capillary length that can be evaluated using MRI. The transportation of blood from inner to outer parts of the capillary is studied by the pores and the relationship among capillary wall thickness, size and the number of pores is examined. BACKGROUND: Characterization of capillary space may obtain much valuable information on the performance of tissues as well as the angiogenesis. METHODS: To estimate the number of pores, a new pseudo-liquid drop model along with appropriate quantitative physiological purposes has been investigated toward indicating a package of data on the capillary space. This model has utilized the MRI perfusion, diffusion and relaxivity parameters such as cerebral blood volume (CBV), apparent diffusion coefficient (ADC), ΔR 2 and Δ R 2 * values. To verify the model, a special protocol was designed and tested on various regions of eight male Wistar rats. RESULTS: The maximum number of pores per capillary length in the various conditions such as recovery, core, normal-recovery, and normal-core were found to be 183 ± 146, 176 ± 160, 275 ± 166, and 283 ± 143, respectively. This ratio in the normal regions was more than that of the damaged ones. The number of pores increased with increasing mean radius of the capillary and decreasing the thickness of the wall in the capillary space. CONCLUSION: Determination of the number of capillary pore may most likely help to evaluate angiogenesis in the tissues and treatment planning of abnormal ones.
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We report a case of a primary intracranial squamous cell carcinoma (SCC) of the cerebello-pontine angle extending through the internal auditory canal, with the unusual presentation of a completely cystic lesion with no diffusion restriction, internal necrotic-hemorrhagic changes and peripheral enhancement, mimicking a cystic acoustic schwannoma. The lack of diffusion restriction and the peripheral enhancement along the lesion, 2 unique findings, supposedly reflected complete cancerization of the epidermoid cyst from which the SCC originated. We discuss the differential diagnosis and review the literature on primary intracranial SCC.
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Angiosarcoma is a rare but very aggressive tumor. It occurs in all organs of the body, and approximately 8% of all angiosarcomas arise in the breast. We reported 2 cases of primary breast angiosarcomas in young women. The 2 patients showed similar clinical features, but were quite different in dynamic contrast-enhanced MR imaging. The 2 patients were treated with mastectomy and axillary sentinel lymph node dissection and confirmed by post-operative pathological test. We suggested that dynamic contrast-enhanced MR imaging was the most helpful imaging tool in the diagnosis and pre-operative evaluation of the breast angiosarcoma.
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Although imaging studies are not typically performed for clinical diagnosis of cervicitis, in this case magnetic resonance imaging (MRI) was performed because a lesion with a tumor-like gross appearance was found in the uterine cervix. We present a case of cervicitis in which clinical, imaging and pathological features overlapped with those of gastric-type mucinous adenocarcinoma (GAS). The patient, a 30-year-old woman, was referred to a gynecologist with a complaint of watery vaginal discharge. On visual examination, the uterine cervix was irregularly enlarged and bled easily, suggesting cervical cancer. The next day, the patient had a fever of 39°C and blisters appeared on her vulva due to herpes simplex virus type II infection. MRI showed a diffusely enlarged cervix with poorly marginated high signal intensity on T2-weighted imaging (WI) and apparent diffusion coefficient map as well as strong enhancement on contrast-enhanced T1WI, which are findings consistent with GAS. Although a punch biopsy showed only mild atypia of the cervical glands, this was not enough to completely rule out GAS. Consequently, laser conization of the lesion was performed for definitive diagnosis, and the diagnosis of cervicitis was made. Acute cervicitis can be difficult to differentiate from GAS based on symptoms, results of cervical biopsy and MR imaging because of their overlapping features. Even when a patient presents with a lesion with tumor-like gross appearance, acute cervicitis should be included in the differential diagnosis if the result of cervical biopsy is negative, especially when accompanied by infection-like fever.
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Purpose: To evaluate the early response of chemoradiotherapy (CRT) in nasopharyngeal carcinoma (NPC) based on intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and three-dimensional pseudo-continuous arterial spin labeling (3D pCASL). Materials and methods: Forty patients diagnosed with NPC were recruited and divided into complete remission (CR) and partial remission (PR) group after CRT. All patients underwent IVIM and ASL and the related parameters was obtained. These parameters include pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), average blood flow ( BFavg), minimum blood flow (BFmin), and maximum blood flow (BFmax). Student's t test was used to compare the difference in ASL and IVIM derived parameters between CR and PR. The Areas under curve (AUC) of the receiver operating characteristic (ROC) was used to analyze the diagnostic performance of each parameter of ASL and IVIM to the treatment outcome. Results: the D value of IVIM in CR group was lower than that of the PR group ( P = 0.014),. Among the parameters of ASL, the BFavg and BFmax of the CR group were higher than those of the PR group(p = 0.004,0.013), but the BFmin had no statistical significance in the two groupsï¼P = 0.54ï¼. AUC of D, BFavg, and BFmax is about 0.731, 0.753, and 0.724, respectively, all of their combined AUC diagnosis was 0.812. Conclusion: The early response of NPC after CRT can predict by IVIM's diffusion parameters and ASL-related blood flow parameters.
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Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare chronic central-nervous-system inflammatory disorder that became known only recently, and the pathogenesis of CLIPPERS remains poorly understood. This report presents clinical and radiological features of a rare case: a young female patient who rapidly died of suspected CLIPPERS. Helpful multiparametric MRI diagnostic criteria are proposed that can help discriminate CLIPPERS from non-CLIPPERS pathologies. We reviewed clinical history, symptoms, quantitative data from brain multiparametric MRI before and after treatment, and histopathological data. Perfusion-weighted imaging revealed a decrease in regional cerebral blood flow by 31% and in cerebral blood volume by 64%, with a moderate increase in transit time and in time to peak by up to 23% in affected pontine and cerebral white matter. As estimated by diffusion tensor imaging, there was elevated density of tracts (n/mm2) and a decrease of fraction anisotropy (×10-3 mm/s2) in the patient's pons as compared to a healthy control: density of tracts = 13.5 vs 12.4 and fraction anisotropy = 0.32 vs 0.45, respectively. Macromolecular proton fraction values proved to be reduced (15.8% and 14.5% in the control, respectively) in the patient's cerebral peduncles by 3% and in the pons by 4.1% and in a periventricular white matter lesion by 6.4% (11.3% in the normal-looking contralateral hemisphere). Based on our findings, we argue that quantitative MRI techniques may be a valuable source of biomarkers and reliable diagnostic criteria and can shed light on the pathogenesis and exact nosological position of this disorder.
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Pyomyomas are rare lesions that develop from the suppurative degeneration of ischemic leiomyomas. Pyomyomas can lead to sepsis, so early diagnosis is crucial. Due to their rarity and often nonspecific findings on ultrasonography and computed tomography diagnosis is often delayed. We present a case of a woman who presented with abdominal pain and fever. The computed tomography showed a large hypodense uterine lesion with slight peripheral enhancement without gas in the lesion. The diffusion-weighted magnetic resonance imaging showed restricted diffusion, demonstrating the presence of pus and confirming the diagnosis of pyomyoma. Diffusion-weighted imaging should be done in cases of suspected pyomyomas when computed tomography findings are nonspecific.
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Myositis and myonecrosis are rare sequela of coronavirus disease 2019 (COVID-19). Until now, it has not been seen in muscles of the head and neck. We present a 22-year-old male with 4 months of retroauricular headaches following COVID-19 infection. Magnetic resonance imaging revealed rim-enhancing fluid collections in the bilateral masticator spaces which were sampled by fine-needle aspiration. We also discuss this case in the context of the current understanding of COVID-19-related myositis.
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Introduction: Dengue is a common febrile illness caused by Dengue virus and spread by Aedes mosquitoes. The neurological complications like encephalopathy or encephalitis or immune-mediated neurological syndromes are uncommon though. Discrete neuroimaging findings in this setting are even rarer. We report a case of dengue encephalitis with uncommon MRI features in a young female. Case presentation: The patient presented with complains of fever, vomiting, weakness in all limbs and difficulty in speech. Neurological examination revealed bilateral horizontal gaze palsy with impaired oculo-cephalic reflex, bulbar dysarthria and quadriplegia with bilateral planters up-going. Laboratory reported anemia, thrombocytopenia and positive NS1 antigen while excluding other tropical and immunological diseases. Brain MRI revealed extensive thalamic involvement as unique "double-doughnut" sign along with lesions in brainstem. The patient received supportive treatment in intensive unit and was discharged following improvement in clinical condition and laboratory reports. Clinical discussion: Dengue can infect the central nervous system directly as encephalitis or can have neurological consequences following multi-organ dysfunction and shock as encephalopathy or post-infection immunological syndromes as Guillain-Barré Syndrome or cerebrovascular complications or dengue muscle dysfunction. The MRI appearance of "double-doughnut" sign points towards dengue encephalitis in appropriate setting. Conclusion: A high index of suspicion is required to make a diagnosis of dengue encephalitis. The "double-doughnut" sign in MRI sequences has the potential to become a diagnostic marker for dengue encephalitis.
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PURPOSE: The aim of this study was to prospectively compare the therapy response and safety of microwave (MWA) and radiofrequency ablation (RFA) for the treatment of liver metastases using a dual ablation system. METHODS: Fifty patients with liver metastases (23 men, mean age: 62.8 ± 11.8 years) were randomly assigned to MWA or RFA for thermal ablation using a one generator dual ablation system. Magnetic resonance imaging (MRI) was acquired before treatment and 24 h post ablation. The morphologic responses to treatment regarding size, volume, necrotic areas, and diffusion characteristics were evaluated by MRI. Imaging follow-up was obtained for one year in three months intervals, whereas clinical follow-up was obtained for two years in all patients. RESULTS: Twenty-six patients received MWA and 24 patients received RFA (mean diameter: 1.6 cm, MWA: 1.7 cm, RFA: 1.5 cm). The mean volume 24 h after ablation was 37.0 cm3 (MWA: 50.5 cm3, RFA: 22.9 cm3, P < 0.01). The local recurrence rate was 0% (0/26) in the MWA-group and 8.3% (2/24) in the RFA-group (P = 0.09). The rate of newly developed malignant formations was 38.0% (19/50) for both groups (MWA: 38.4%, RFA: 37.5%, P = 0.07). The overall survival rate was 70.0% (35/50) after two years (MWA: 76.9%, RFA: 62.5%, P = 0.60). No major complications were reported. CONCLUSION: In conclusion, MWA and RFA are both safe and effective methods for the treatment of liver metastases with MWA generating greater volumes of ablation. No significant differences were found for overall survival, rate of neoplasm, or major complications between both groups.
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Hydatid cyst is an uncommon parasitic disease caused by larval stages of Echinococcus granulosus. The liver is the most frequently affected organ followed by the lungs and the spleen. Intracranial hydatid cysts are uncommon and occur mostly in supratentorial region. It can present with nonspecific symptoms and can be difficult to diagnose, thus regardless of unusual clinical presentation and unusual location of cystic lesion in brain, it is crucial to keep hydatid cyst as one of the differentials. We describe a case of a 28-year-old male who presented with headache, vomiting and cerebellar signs. MRI showed multiple cystic lesions in posterior fossa with asymmetrically dilated posterior horn of left lateral ventricle. Biopsy from one of the cystic lesions from posterior fossa was performed which confirmed the diagnosis of hydatid cyst. Patient was started on Albendazole and subsequently planned for surgery.
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Background and purpose: Diagnostic information about cell density variations and microscopic tissue anisotropy can be gained from tensor-valued diffusion magnetic resonance imaging (MRI). These properties of tissue microstructure have the potential to become novel imaging biomarkers for radiotherapy response. However, tensor-valued diffusion encoding is more demanding than conventional encoding, and its compatibility with MR scanners that are dedicated to radiotherapy has not been established. Thus, our aim was to investigate the feasibility of tensor-valued diffusion MRI with radiotherapy dedicated MR equipment. Material and methods: A tensor-valued diffusion protocol was implemented, and five healthy volunteers were scanned with different resolutions using conventional head coil and radiotherapy coil setup with fixation masks. Signal-to-noise-ratio (SNR) was evaluated to assess the risk of signal bias due to rectified noise floor. We also evaluated the repeatability and reproducibility of the microstructure parameters. One patient with brain metastasis was scanned to investigate the image quality and the transferability of the setup to diseased tissue. Results: A resolution of 3 × 3 × 3 mm3 provided images with SNR > 3 for 93 % of the voxels using radiotherapy coil setup. The parameter maps and repeatability characteristics were comparable to those observed with a conventional head coil. The patient evaluation demonstrated successful parameter analysis also in tumor tissue, with SNR > 3 for 93 % of the voxels. Conclusion: We demonstrate that tensor-valued diffusion MRI is compatible with radiotherapy fixation masks and coil setup for investigations of microstructure parameters. The reported reproducibility may be used to plan future investigations of imaging biomarkers in brain cancer radiotherapy.
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Primary dural lymphoma is a rare subtype of primary central nervous system lymphoma. Primary dural lymphoma may be radiologically misdiagnosed as it shares similar imaging characteristics with several pathologies, including meningiomas and subdural or epidural hematomas. We present a patient who was originally diagnosed with a subdural hematoma following a syncopal episode on computed tomography. Follow-up magnetic resonance imaging of the brain demonstrated heterogeneously enhancing dural-based mass overlying the left frontoparietal convexity associated with bidirectional dural tails, suggestive of a malignant meningioma. Neurosurgical histopathology revealed marginal zone B-cell lymphoma. This case represents the potential difficulty in diagnosing primary dural lymphoma, especially in the setting of uncertain clinical history and obscured imaging features.
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Purpose: Differentiating Warthin tumor (WT) from pleomorphic adenoma (PA) is of primary importance due to differences in patient management, treatment and outcome. We sought to evaluate the performance of MRI-based radiomic features in discriminating PA from WT in the preoperative setting. Methods: We retrospectively evaluated 81 parotid gland lesions (48 PA and 33 WT) on T2-weighted (T2w) images and 52 of them on post-contrast fat-suppressed T1-weighted (pcfsT1w) images. All MRI examinations were carried out on a 1.5-Tesla MRI scanner, and images were segmented manually using the software ITK-SNAP (www.itk-snap.org). Results: The most discriminative feature on pcfsT1w images was GLCM_InverseVariance, yielding area under the curve (AUC), sensitivity and specificity of 0.9, 86 % and 87 %, respectively. Skewness was the feature extracted from T2w images with the highest specificity (88 %) in discriminating WT from PA. Conclusion: Radiomic analysis could be an important tool to improve diagnostic accuracy in differentiating PA from WT.
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Background and purpose: Glioblastoma (GBM) patients have a dismal prognosis. Tumours typically recur within months of surgical resection and post-operative chemoradiation. Multiparametric magnetic resonance imaging (mpMRI) biomarkers promise to improve GBM outcomes by identifying likely regions of infiltrative tumour in tumour probability (TP) maps. These regions could be treated with escalated dose via dose-painting radiotherapy to achieve higher rates of tumour control. Crucial to the technical validation of dose-painting using imaging biomarkers is the repeatability of the derived dose prescriptions. Here, we quantify repeatability of dose-painting prescriptions derived from mpMRI. Materials and methods: TP maps were calculated with a clinically validated model that linearly combined apparent diffusion coefficient (ADC) and relative cerebral blood volume (rBV) or ADC and relative cerebral blood flow (rBF) data. Maps were developed for 11 GBM patients who received two mpMRI scans separated by a short interval prior to chemoradiation treatment. A linear dose mapping function was applied to obtain dose-painting prescription (DP) maps for each session. Voxel-wise and group-wise repeatability metrics were calculated for parametric, TP and DP maps within radiotherapy margins. Results: DP maps derived from mpMRI were repeatable between imaging sessions (ICC > 0.85). ADC maps showed higher repeatability than rBV and rBF maps (Wilcoxon test, p = 0.001). TP maps obtained from the combination of ADC and rBF were the most stable (median ICC: 0.89). Conclusions: Dose-painting prescriptions derived from a mpMRI model of tumour infiltration have a good level of repeatability and can be used to generate reliable dose-painting plans for GBM patients.
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Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome presents with the features of herpes simplex encephalitis (HSE), which is rare and has been described in only a few case reports. Our case describes a 17-year-old female with no significant previous medical history presenting with an acute onset of fever, headache, and epilepsy, similar to HSE. Computed tomography of the brain showed bilateral basal ganglia calcification. Magnetic resonance imaging demonstrated gyriform restricted diffusion with T2-weighted images prolongation. Further investigation showed elevated blood lactate concentration at rest. Hence, MELAS was suspected and the diagnosis was confirmed by the presence of a nucleotide 3243 AâG mutation in the mitochondrial DNA. The clinical presentation and imaging studies of MELAS are variable and may mimic those of HSE. Infection may have also precipitated MELAS manifestation in this patient. Laboratory features, such as elevated lactate, basal ganglia calcification, and gyriform restricted diffusion may be helpful in identifying patients with MELAS.
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Objective: To assess the diagnostic value of fluorine 18 (18F)-labeled prostate-specific membrane antigen (PSMA)-1007 Positron emission tomography/Magnetic resonance imaging (PET/MRI) and compared with that of biparametric MRI (bpMRI) for the detection of prostate cancer (PCa). Materials and methods: The study enrolled 29 patients with suspected PCa preoperatively who underwent 18F-PSMA-1007 PET/MRI and subsequent targeted biopsy for suspected PCa lesions. Two readers independently assessed the images of each suspected PCa lesion and determined their overall assessment category on bpMRI and 18F-PSMA-1007 PET/MRI. By using biopsy histopathology as the reference standard, the accuracies of 18F-PSMA-1007 PET/MRI and bpMRI for the detection of PCa lesion were determined. Furthermore, the receiver-operating characteristic (ROC) curves of their semi-quantitative parameters of the optimal standardized uptake value (SUVmax) and apparent diffusion coefficient (ADC) for detecting PCa lesions were derived, and their correlations with the International Society of Urological Pathology (ISUP) grade were reported. Results: Of the 48 suspected PCa lesions in 29 patients, 38 were pathologically diagnosed with clinically significant PCa and 10 with nonprostate cancer (non-PCa) lesions. Compared with the pathological results, 18F-PSMA-1007 PET/MRI demonstrated much greater diagnostic accuracy (area under the curve, AUC), sensitivity, specificity, positive predictive value, and negative predictive value than bpMRI: 0.974 versus 0.711, 94.74% versus 92.11%, 100% versus 50%, 100% versus 87.50%, and 83.33% versus 62.50%, respectively. The semi-quantitative parameters of SUVmax demonstrated a higher AUC of 0.874 than that of ADC with 0.776 for detecting PCa. The ISUP grade was positively associated with SUVmax at spearman's rho correlation coefficient (Rho) = 0.539, p = 0), but not associated with ADC (Rho = -0.105, p = 0.529). Conclusion: The diagnostic value of 18F-PSMA-1007 PET/MRI for the detection of PCa is better than that of bpMRI, and a high SUVmax may indicate a lesion with a high ISUP grade.
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Background: Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is a relatively new entity of demyelinating diseases, clinically presenting with optic neuritis, transverse myelitis, or encephalic symptoms. Typical radiological features include demyelinating cerebral and spinal lesions, cortical involvement, leptomeningeal enhancement, or tumefactive lesions. Here we present a rare case of a young patient with extensive brain stem lesion on the MRI while exhibiting nystagmus, singultus and somnolence. Case presentation: A 30-year-old male patient presented initially with fever and impaired consciousness, but furthermore developed nystagmus, singultus and tetraparesis during the following week. Repeated MRI examinations revealed extensive brain stem edema with notable bilateral affection of the cerebellar peduncles and the pons. Antiviral and antibiotic treatment was changed to intravenous corticosteroids and immunoglobulins as soon as the diagnosis of MOGAD was established by testing serum and cerebrospinal fluid positive for MOG specific antibodies. MRI alterations vanished completely over time with a delayed, nearly complete clinical recovery of our patient. Conclusion: Brain stem affection in MOGAD is rare. However, in patients presenting with an unclear brain stem encephalitis the possibility of MOGAD should be considered and tested using MOG antibodies. In case of a positive testing treatment with steroids and immunoglobulins seems recommendable.
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PURPOSE: Bi-parametric magnetic resonance imaging (bpMRI) with diffusion-weighted images has wide utility in diagnosing clinically significant prostate cancer (csPCa). However, bpMRI yields more false-negatives for PI-RADS category 3 lesions than multiparametric (mp)MRI with dynamic-contrast-enhanced (DCE)-MRI. We investigated the utility of synthetic MRI with relaxometry maps for bpMRI-based diagnosis of csPCa. METHODS: One hundred and five treatment-naïve patients who underwent mpMRI and synthetic MRI before prostate biopsy for suspected PCa between August 2019 and December 2020 were prospectively included. Three experts and three basic prostate radiologists evaluated the diagnostic performance of conventional bpMRI and synthetic bpMRI for csPCa. PI-RADS version 2.1 category 3 lesions were identified by consensus, and relaxometry measurements (T1-value, T2-value, and proton density [PD]) were performed. The diagnostic performance of relaxometry measurements for PI-RADS category 3 lesions in peripheral zone was compared with that of DCE-MRI. Histopathological evaluation results were used as the reference standard. Statistical analysis was performed using the areas under the receiver operating characteristic curve (AUC) and McNemar test. RESULTS: In 102 patients without significant MRI artefacts, the diagnostic performance of conventional bpMRI was not significantly different from that of synthetic bpMRI for all readers (p = 0.11-0.79). The AUCs of the combination of T1-value, T2-value, and PD (T1 + T2 + PD) for csPCa in peripheral zone for PI-RADS category 3 lesions were 0.85 for expert and 0.86 for basic radiologists, with no significant difference between T1 + T2 + PD and DCE-MRI for both expert and basic radiologists (p = 0.29-0.45). CONCLUSION: Synthetic MRI with relaxometry maps shows promise for contrast media-free evaluation of csPCa.
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We describe a case of a 52 year-old woman who was hospitalized with rhombencephalitis caused by Borrelia burgdorferi sensu lato. The patient presented with intermittent fever, dry cough, fatigue, global headache, night sweats, unintentional weight loss, and neurological symptoms like diplopia, tremor, paresthesia and ataxia. Examination of serum and cerebrospinal fluid (CSF) revealed positive Borrelia burgdorferi-specific antibody index and presence of CSF oligoclonal IgG bands, indicating intrathecal synthesis of Borrelia-specific antibodies. The clinical and biochemical picture thus suggested neuroborreliosis. Unexpectedly a magnetic resonance imaging (MRI) scan demonstrated inflammation in rhombencephalon that are extremely rare in patients with neuroborreliosis. The patient was treated with intravenous ceftriaxone with rapid improvement of her symptoms. The MRI findings were in regress six weeks after onset of antibiotic treatment, and normalized after about seven months.