Serial proton MR spectroscopy and diffusion imaging findings in HIV-related herpes simplex encephalitis

We report the case of pathologically proved atypical herpes simplex encephalitis (HSE) in a 40-year-old male patient with AIDS who was followed up by MR imaging, which included diffusion-weighted imaging and proton MR spectroscopy ((1)H-MRS). MR revealed sparing of hippocampi and limbic cortices, necrosis of both cingulate gyri, and cerebellar involvement. Increased diffusivity and severe metabolic alterations were compatible with biopsy findings of necrotizing inflammation. Clinical recovery corresponded with partial metabolite and diffusion normalization and a myo-inositol increase that indicated evolving gliosis formation further corroborated by immunohistochemistry results. (1)H-MRS and diffusion-weighted imaging may both support the diagnosis of HSE in patients with AIDS and help in the follow-up of necrotizing inflammation.     

Diffusion-weighted MR imaging findings in a patient with herpes simplex encephalitis

INTRODUCTION: Herpes simplex meningoencephalitis is one of the most common viral central nervous system infection in adults. Early diagnosis is essential for treatment. CASE REPORT: We present a case of a 68-year-old female patient with herpes simplex infection. On admission, she was in severe clinical condition. Diffusion-weighted (DW) magnetic resonance imaging detected brain involvement better than conventional sequences. After acyclovir therapy, the patient fully recovered. CONCLUSION: DW magnetic resonance imaging is expected to provide a more sensitive imaging in herpes simplex patients than conventional sequences.     

Metachromatic leukodystrophy: diffusion MR imaging findings

Herein the case of a 10-month-old boy with metachromatic leukodystrophy is reported. Diffusion MR imaging performed with an echo-planar trace sequence revealed a cytotoxic edema-like pattern (high signal intensity on b = 1000 s/mm(2) images and low apparent diffusion coefficient values) in the affected white matter in the absence of an ischemic condition. This finding was unchanged at a 6-month follow-up, as revealed by diffusion MR imaging. A gradient-echo diffusion sequence, reverse fast imaging in steady-state precession, revealed hyperintense changes at the corresponding regions. It is likely that the cytotoxic edematous pattern (restricted diffusion pattern) reflected restriction of mobility of the water molecules within abnormal portions of the myelin sheath, because impaired myelin breakdown and reutilization are known features of metachromatic leukodystrophy.     

SPECT and MR imaging in herpes simplex encephalitis

Two cases of necrotizing herpes simplex encephalitis (HSE) were investigated with 99mTc-hexamethylpropyleneamineoxime (HMPAO) SPECT and MR. The clinical course was compared with the neuroimaging results. In the acute stage, the increased HMPAO uptake matched the MR hyperintense signal in the limbic temporal lobe and in the basal ganglia. Protracted inflammation was accompanied by persistently high HMPAO uptake. The sequelae of HSE were characterized by decreased HMPAO uptake and postnecrotic widening of the temporal horns. The "limbic" pattern recognized in both SPECT and MR reflects the basic pathophysiology and neuropathology of HSE. Both methods may be useful in the diagnosis and follow-up of HSE.     

MR findings in neonatal herpes simplex encephalitis type II

The CT findings in neonatal herpes simplex encephalitis (HSE) type II have been previously described, whereas magnetic resonance (MR) findings as yet have not. Early CT findings can be subtle and difficult to detect. However, as the abnormalities evolve, most notably the strikingly increased density of cortical gray matter, they appear highly characteristic of neonatal HSE type II. This case report with neuropathologic verification describes serial MR and CT findings in HSE type II that suggest an etiology of the increased density characteristically seen on CT scans; it does not appear to be hemorrhage or calcification.     

Acute carbon monoxide poisoning: diffusion MR imaging findings

During the acute stage of carbon monoxide poisoning, diffusion MR images obtained at b=1000 s/mm2 revealed high signal intensity lesions in the white matter, consistent with restricted diffusion. Low apparent diffusion coefficient values (0.18-0.34 x 10(-3) mm2/s) were noted in the affected white matter regions. Follow-up MR imaging performed 16 days later revealed disappearance of white matter lesions, suggesting that during the acute stage of carbon monoxide poisoning, white matter can be more sensitive than gray matter to ischemia.     

Pantothenate kinase-associated neurodegeneration: MR imaging,proton MR spectroscopy,and diffusion MR imaging findings

We herein report the case of a 15-year-old male patient with pantothenate kinase-associated neurodegeneration. The classic "eye-of-the-tiger" appearance was initially present on the globus pallidi on T2-weighted MR images and had disappeared by the time of the 10-month follow-up examination. Fluid-attenuated inversion recovery images revealed marked hypointensity in the globus pallidi and dentate nuclei and high signal intensity changes in the deep cerebral white matter. Proton MR spectroscopy revealed markedly decreased N-acetylaspartate in the globus pallidi, associated with decreased N-acetylaspartate and increased myoinositol in the deep cerebral white matter. Diffusion MR images (b=1000 s/mm(2)) were negative (normal appearing) for deep cerebral white matter lesions, whereas apparent diffusion coefficient values were slightly increased (1.08-1.12 x 10(-3) mm(2)/s), compared with the apparent diffusion coefficient values from the normal white matter regions. Apparent diffusion coefficient values in the globus pallidi were lower than those in the unaffected thalamus.     

小儿流行性乙型脑炎的MR成像及其扩散加权成像特征

目的探讨小儿乙型脑炎的MRI表现及其扩散加权成像（DWI）的特征。方法16例临床诊断符合小儿乙型脑炎的患者，均行头颅常规MRI和轴面DWI，其中7例在发病10d内检查，9例在10d后检查。观察患者脑DWI、T2WI序列的表现；同时测量感兴趣区的表观扩散系数（ADC）值，并将病灶的ADC值与其对应的发病持续时间作相关分析。结果脑部病变区主要呈稍长T1、长T2信号，丘脑受累最常见。16例患者中，15例丘脑受累，其中6例病变仅累及丘脑。7例10d内行MR检查者，病灶在DWI较T2WI信号高，而且病变范围更清楚，其中2例在DWI还显示了T2WI未能显示的病灶；9例发病10d后行MR检查者，T2WI显示病变较DWI清晰。丘脑病灶的ADC值与其病程呈正相关（r=0．84，P〈0．01）。结论 小儿乙型脑炎在MRI上常表现为较特征的丘脑受累，结合临床，DWI对乙型脑炎的早期诊断有一定帮助。     

MR imaging of herpes simplex type 1 encephalitis in infants and young children: a separate pattern of findings

OBJECTIVE: We sought to identify the initial MR findings of herpes simplex encephalitis in infants and young children. CONCLUSION: MR imaging findings of herpes encephalitis in infants and young children appear to differ from those seen in neonates, older children, and adults. Appreciation of this MR imaging pattern coupled with a strong clinical suspicion of herpes helps to ensure the correct diagnosis is made.     

Contrast-enhanced magnetization transfer saturation imaging improves MR detection of herpes simplex encephalitis.

Cranial MR imaging was performed in three patients in whom herpes simplex encephalitis was subsequently proved. In all cases, the postcontrast T1 weighted MR images obtained with magnetization transfer saturation showed greater central nervous system involvement than was apparent on the conventional MR images. Specifically, the postcontrast magnetization transfer images were superior at delineating generalized meningeal enhancement as well as focal areas of brain involvement not seen on noncontrast T2-weighted images orconventionalpostcontrast T1-weightedimages.     

Rocky Mountain spotted fever encephalitis: MR findings.

We describe a case of Rocky Mountain spotted fever encephalitis and present the associated findings of an MR examination of the brain, which showed increased signal intensity in the distribution of perivascular spaces. Resolution of the MR abnormalities coincided with clinical improvement.     

Subacute sclerosing panencephalitis findings at MR imaging, diffusion MR imaging, and proton MR spectroscopy

A case of subacute sclerosing panencephalitis in a 2-year-old boy is reported. In addition to asymmetric lesions in the parietotemporal lobes, right thalamus, and globus pallidus, symmetric patterns were notable in the brain stem, middle cerebellar pedincles, and dentate nuclei. Proton MR spectroscopy revealed markedly decreased N-acetylaspartate peaks and normal choline and myo-inositol levels in the lesions. Diffusion MR imaging revealed an elevated diffusion pattern manifested with high apparent diffusion coefficient values (1.14-1.60 x 10(-3) mm(2)/s) compared with those in normal-appearing brain tissue (0.65-1.00 x 10(-3) mm(2)/s) and subtle high signal intensity characteristics on diffusion-weighted images obtained at b = 1000 s/mm(2).     

Diffusion-weighted MR imaging of encephalitis.

OBJECTIVE: Our purpose was to evaluate how well diffusion-weighted MR imaging shows viral or bacterial encephalitis in comparison with conventional MR imaging that includes T1- and T2-weighted spin-echo and fluid-attenuated inversion-recovery sequences. CONCLUSION: In nine of the 13 patients examined, diffusion-weighted imaging was superior to other diagnostic imaging sequences (fluid-attenuated inversion-recovery sequences in eight patients and a T2-weighted spin-echo sequence in one patient). Diffusion-weighted imaging can serve as a method of detecting early encephalitic changes.     

Herpes simplex virus pneumonia: high-resolution CT findings

The purpose of this study was to evaluate the high-resolution computed tomographic (HRCT) findings of five adult patients (either immunocompromised or immunocompetent) with herpes simplex virus (HSV) pneumonia. We retrospectively assessed HRCT images of 5 patients (all male patients, age range 39–70 years; mean 62 years) with HSV pneumonia. The specific pathological findings that allowed for a definite diagnosis of HSV pneumonia included the presence of intranuclear inclusion bodies on haematoxylin and eosin staining, or positive immunohistochemical staining. High-resolution CT scans (HiSpeed Advantage or LightSpeed QX/i, GE Healthcare) using 1- or 1.25-mm collimation at 10-mm intervals without intravenous contrast medium injection were assessed, in particular for the presence and distribution of parenchymal abnormalities including ground-glass attenuation, airspace consolidation, nodules and interlobular septal thickening. In two patients, pathological specimens were obtained from open lung biopsy or bronchoscopic biopsy, and were correlated with HRCT findings. Three HRCT patterns of pulmonary abnormalities were identified in our series of HSV pneumonia: predominant areas of diffuse or multifocal ground-glass attenuation, predominant areas of multifocal peribronchial consolidations, and a mixed pattern of both. Histopathologically, areas of ground-glass attenuation seen on HRCT corresponded to diffuse alveolar damage in one patient who underwent open lung biopsy. No specific differences in HRCT findings were seen between the immunocompromised and the immunocompetent patients. In patients suspected of having an acute lower respiratory infection, whether immunocompromised or immunocompetent, a possibility of HSV pneumonia can be included in differential diagnoses when diffuse or multifocal areas of ground-glass attenuation and/or consolidations are seen on HRCT.Herpes simplex virus (HSV) pneumonia can occur in patients with complications of immunosuppression, airway injury from intubation or smoke inhalation [1, 2]. Pathologically, HSV infection can have three main forms of pulmonary involvement: necrotising tracheobronchitis, necrotising pneumonia and interstitial pneumonitis [3]. The interstitial pneumonitis form of HSV pulmonary infection is characterised by diffuse alveolar damage consisting of interstitial lymphocytic infiltration, alveolar haemorrhage and hyaline membrane formation [4].A few reports have previously described the high-resolution CT (HRCT) findings of HSV pneumonia in immunocompromised patients [1, 2], including areas of ground-glass attenuation, airspace consolidation and small centrilobular nodules.The purpose of this study was to evaluate the HRCT findings of five adult patients (either immunocompromised or immunocompetent) with HSV pneumonia.     

Painful heel: MR imaging findings.

Heel pain is a common and frequently disabling clinical complaint that may be caused by a broad spectrum of osseous or soft-tissue disorders. These disorders are classified on the basis of anatomic origin and predominant location of heel pain to foster a better understanding of this complaint. The disorders include plantar fascial lesions (fasciitis, rupture, fibromatosis, xanthoma), tendinous lesions (tendinitis, tenosynovitis), osseous lesions (fractures, bone bruises, osteomyelitis, tumors), bursal lesions (retrocalcaneal bursitis, retroachilleal bursitis), tarsal tunnel syndrome, and heel plantar fat pad abnormalities. With its superior soft-tissue contrast resolution and multiplanar capability, magnetic resonance (MR) imaging can help determine the cause of heel pain and help assess the extent and severity of the disease in ambiguous or clinically equivocal cases. Careful analysis of MR imaging findings and correlation of these findings with patient history and findings at physical examination can suggest a specific diagnosis in most cases. The majority of patients with heel pain can be successfully treated conservatively, but in cases requiring surgery (eg, plantar fascia rupture in competitive athletes, deeply infiltrating plantar fibromatosis, masses causing tarsal tunnel syndrome), MR imaging is especially useful in planning surgical treatment by showing the exact location and extent of the lesion.