Spontaneous intracranial hypotension: report of four cases and review of the literature

Spontaneous intracranial hypotension is an unusual syndrome of postural headache and low cerebrospinal fluid pressure without an established cause. We present four cases, analyze those previously reported in the literature, examine the MRI, CT, angiographic and cisternographic finding and discuss the clinical picture, proposed pathophysiologic mechanisms and potential treatment. Received: 18 October 1997 Accepted: 16 January 1998     

MR findings of spontaneous intracranial hypotension

Purpose:
To present the MR features of spontaneous intracranial hypotension (SIH) and to discuss the correlation of MR features with clinical manifestations. Material and Methods:
Between 1997 and 2000, 15 patients with SIH underwent brain MR investigation. Lumbar puncture for the measurement of cerebrospinal fluid (CSF) pressure was performed in 6 patients. Follow-up MR was obtained in 8 patients after the clinical symptoms had improved. We analyzed the MR findings of SIH, and discuss them in relation to CSF pressure and clinical manifestations. Results:
Fourteen of the 15 patients with SIH had abnormal MR findings. The imaging findings included: diffuse pachymeningeal enhancement in 13 patients; descent of the brain in 6 patients; and subdural effusion/hematoma in 2 patients. Low CSF pressure was shown at lumbar puncture in 5 out of 6 patients. Follow-up MR examination in the symptoms-relieved status demonstrated a recovery of the abnormal MR findings in 6 of 8 patients. Conclusion:
Our data revealed that MR is sensitive in diagnosing SIH. The presence of characteristic clinical manifestations and MR features are virtually diagnostic for SIH syndrome. Invasive lumbar puncture is thus reserved for the equivocal cases.     

Spontaneous intracranial hypotension: morphological findings and CSF flow dynamics studied by MRI

We report on a case of spontaneous intracranial hypotension (SIH) presenting with classic MR findings, such as diffuse smooth thickening and intense contrast enhancement of the dura matter, increased size of the pituitary gland and downward displacement of the brain. In this case an engorgement of the cavernous sinuses is reported as an additional imaging finding of SIH. Moreover, phase-contrast MR study of the CSF flow dynamics revealed at the level of the aqueduct a decrease of the systolic and diastolic flow volume of CSF. A normalization of the flow volume was observed when SIH subsided.     

Spontaneous intracranial hypotension: a study of six cases with MR findings and literature review

Spontaneous intracranial hypotension is clinically characterized by orthostatic headache and other symptoms caused by low cerebrospinal fluid pressure due to leakage of cerebrospinal fluid from dural punctures or other medical causes. The other symptoms are mainly due to traction of the cranial and spinal nerves owing to descent of the brain caused by low cerebrospinal fluid pressure. Magnetic resonance imaging is very useful in the diagnosis because of its characteristic findings. We describe the MRI findings in six cases that had variable clinical presentation.     

Spontaneous intracranial hypotension: the value of brain measurements in diagnosis by MRI

Caudal brain displacement is inconstantly reported as an MRI feature of spontaneous intracranial hypotension (SIH). We reviewed the clinical data and MRI of eight patients diagnosed as having SIH and investigated the possibility of more precise assessment. On midsagittal images we measured four anatomical landmarks: the position of the cerebellar tonsils, fourth ventricle, and infundibular recess, plus the angle between the bicommissural line and a line tangential to the floor of the fourth ventricle; midsagittal images from 89 normal controls were also measured. On statistical analysis, all measurements differed in the two groups, and the difference was significant for the cerebellar tonsils, fourth ventricle, and infundibular recess. Some overlap between patients and controls was found for each measurement; however, all the patients had two (two patients) or more (six) values outside the range in normal controls range or not above their 1st quartile. Measurement of the position of the third ventricle seemed particularly sensitive. We suggest that examination of midsagittal images can help in diagnosing clinically suspected SIH. Received: 17 July 2000 Accepted: 20 November 2000     

A case of spontaneous intracranial hypotension in a 45-year-old male with headache,behavior changes and altered mental status

Spontaneous intracranial hypotension is a rare disease that results from low cerebrospinal fluid (CSF) volume caused by leakage of CSF from the spine in the absence of lumbar puncture, spine surgery, or intervention. The most common presentation is the headache that is usually but not invariably orthostatic. The underlying pathology is a CSF leak resulting from dural weakness involving the nerve root sleeves, ventral dural tears associated with calcified disc herniations, or CSF venous fistula. In severe cases, neuropsychiatric symptoms and changes in mental status may develop. Some case reports also mention gait disturbances, slurred speech, and urinary incontinence. The constellation of neuropsychiatric symptoms similar to behavior variant frontotemporal dementia in the presence of “brain sag” on MRI is known as frontotemporal brain sagging syndrome, first described by Wicklund et al. (4). The disease presents a diagnostic challenge to the primary care physicians, who are the first to see these patients. Brain and spine imaging is key to diagnoses but requires a high index of suspicion, as very rarely are all classic findings of intracranial hypotension present in the same patient. Here we discuss a case of spontaneous intracranial hypotension in a 45-year-old male patient who presented with headache, drowsiness, incoherent speech, behavior symptoms, and altered mental status.     

Spontaneous craniospinal hypotension

Spontaneous cerebrospinal fluid (CSF) leak has been called "spontaneous intracranial hypotension," emphasizing the intracranial symptoms and imaging findings. We present a patient with spontaneous CSF leak whose initial spinal magnetic resonance imaging (MRI) findings were thought to represent epidural tumor or infection. Subsequent MRI examinations showed an improvement of both intracranial and spinal CSF hypotension findings coinciding with clinical symptom resolution. We propose the term "spontaneous craniospinal hypotension" to better emphasize this syndrome's unifying intracranial and spinal pathophysiology and imaging findings.     

A notable improvement in spontaneous intracranial hypotension (SIH) after delivery in a pregnant woman: A case report

Spontaneous intracranial hypotension (SIH) is a rare condition where the CSF pressure is lower than expected. In this report, we introduce a case of SIH in a 32-year-old pregnant woman who came to our emergency department at 32 weeks’ gestation with a postural and bilateral headache. After MRI confirmation, conservative treatment was started for her, and a cesarean section was scheduled. After the operation, CT-myelography and CT-cisternography were performed for the patient to find the source of the CSF leak, which was located in the C3-C5 level. Still, due to the dangerous nature of the operation, the patient continued supportive treatment and had a significant improvement in his next MRI without any invasive procedure.     

自发性低颅压综合征脑脊液间隙显像的影像学特征分析

目的 探讨自发性低颅压综合征（SIH）患者放射性核素脑脊液间隙显像（RNC）的影像学特点及其临床意义。 方法 回顾性分析2012年5月至2017年1月福建省立医院收治的19例SIH患者,均经腰椎穿刺脊髓蛛网膜下腔注射99Tcm-DTPA,行多时相脑脊液间隙显像,对99Tcm-DTPA异常分布处加做SPECT/CT断层融合显像及MRI扫描。综合分析RNC的影像学特点。计数资料的组间比较采用 χ 2 检验。 结果 RNC可通过显示脊髓或鼻部脑脊液漏点等直接征象诊断SIH;也可通过观察脑脊液循环过程异常,如：显像剂上升缓慢,难以抵达脑池、大脑凸面、上矢状窦等及膀胱、肾脏早期显像等间接征象诊断SIH。RNC检出脑脊液漏17例。直接脑脊液漏患者12例,其中颈、胸段9例,脑脊液鼻漏2例,大流量脑脊液漏（腰段）患者1例。RNC正常者2例。MRI[阳性率为58.8%（10/17）]与RNC[阳性率为88.2%（15/17）]对SIH低颅压诊断的差异无统计学意义（χ2=0.101,P>0.05）;12例RNC检出漏口的相应部位MRI仅检出1例。 结论 RNC可通过直接或间接征象协助SIH的病因诊断,在脑脊液漏口检出上明显优于MRI,并可反映脑脊液漏的流量,便于个体化治疗,在SIH的诊疗中有重要的应用价值。     

Dual energy CT for the identification of CSF-Venous Fistulas and CSF leaks in spontaneous intracranial hypotension: Report of four cases

Spontaneous intracranial hypotension (SIH) is a debilitating condition caused by spinal CSF leaks or CSF-venous fistulas (CVFs). Localizing the causative CSF leak or CVF is critical for definitive treatment but can be difficult using conventional myelographic techniques because these lesions are often low contrast compared to background, diminutive, and in some cases may be mistaken for calcified structures. Dual energy CT (DECT) can increase the conspicuity of iodinated contrast compared to background and can provide the ability to distinguish materials based on differing anatomic properties, making it well suited to address the shortcomings of conventional myelography in SIH. The purpose of this report is to illustrate the potential benefits of using DECT as an adjunct to traditional myelographic techniques in order to increase the conspicuity of these often-subtle CVFs and CSF leaks. This retrospective case series included 4 adult patients with SIH who demonstrated findings equivocal for either CVF or CSF leak using our institution''s standard initial CT myelogram and in whom subsequent evaluation with DECT ultimately helped to identify the CVF or CSF leak. DECT demonstrated utility by increasing the conspicuity of two subtle CVFs compared to background and also helped to differentiate between calcified osteophytes and extradural contrast in 2 CSF leaks, confirming their presence and identifying the causative pathology. Our observations demonstrate the benefit of DECT as a problem-solving tool in the accurate diagnosis and localization of CVFs and CSF leaks.     

Discrepant time course of cranial and spinal subdural collections in a case of SIH treated by EBP

The MR monitoring of a patient with acute spontaneous intracranial hypotension successfully treated by epidural blood patch revealed strikingly different time course of the initially concomitant cranial and spinal subdural fluid collections. This undescribed feature suggested different pathophysiological mechanisms for the disorder in the two locations and should be kept in mind when imaging patients with the condition.     

Contrast-enhanced MR myelography in spontaneous intracranial hypotension: description of an artefact imitating CSF leakage

In contrast-enhanced (CE) MR myelography, hyperintense signal outside the intrathecal space in T1-weighted sequences with spectral presaturation inversion recovery (SPIR) is usually considered to be due to CSF leakage. We retrospectively investigated a hyperintense signal at the apex of the lung appearing in this sequence in patients with SIH (n = 5), CSF rhinorrhoea (n = 2), lumbar spine surgery (n = 1) and in control subjects (n = 6). Intrathecal application of contrast agent was performed in all patients before MR examination, but not in the control group. The reproducible signal increase was investigated with other fat suppression techniques and MR spectroscopy. All patients and controls showed strongly hyperintense signal at the apex of the lungs imitating CSF leakage into paraspinal tissue. This signal increase was identified as an artefact, caused by spectroscopically proven shift and broadening of water and lipid resonances (1–2 ppm) in this anatomical region. Only patients with SIH showed additional focal enhancement along the spinal nerve roots and/or in the spinal epidural space. In conclusion CE MR myelography with spectral selective fat suppression shows a reproducible cervicothoracic artefact, imitating CSF leakage. Selective water excitation technique as well as periradicular and epidural contrast collections may be helpful to discriminate between real pathological findings and artefacts.     

Spontaneous intracranial hypotension: use of unenhanced MRI

We report a case of spontaneous intracranial hypotension diagnosed with unenhanced cranial MRI, showing laminar subdural fluid and engorgement of the hypophysis and perisellar sinuses. Cerebrospinal fluid pressure was low. MRI was normal after resolution of symptoms. Prior reports emphasise the enhancing pachymeninges seen in this syndrome. We maintain that, when subdural collections and perisellar engorgement are detected on unenhanced MRI in the proper clinical setting, contrast enhancement may not be necessary for the diagnosis. Received: 23 June 1999 Accepted: 13 August 1999     

海绵窦海绵状血管瘤的MRI表现(2例及文献复习)

目的:探讨海绵窦海绵状血管瘤(cavernous sinus hemangiomas,CSHAs)的MRI表现特征。方法:回顾性分析经手术病理证实的2例CSHAs的MRI表现,并复习文献资料。结果:海绵状血管瘤位于左、右侧海绵窦各1例,MRI呈分叶状,边缘清晰,呈长T1长T2信号,信号均匀,未见出血及钙化。增强扫描病变明显强化,强化程度高于垂体,并表现出渐进性、向心性强化的特点。结论:CSHAs的MR表现具有特征性,MR检查有助于作出正确的定位和定性诊断。     

Testicular microlithiasis: US findings in six pediatric cases and literature review

The aim of this article is to report on six pediatric cases of testicular microlithiasis (TM) and to review literature reports, in order to schedule US and/or other control examinations, particularly when concomitant focal or diffuse alterations of the testicular parenchymal structure are present, considering the possible association of TM with testicular tumors. Six patients (age range 4–12 years) underwent US examination for scrotal trauma (two cases) unilateral cryptorchidism (one case) follow-up after orchidopexy for bilateral cryptorchidism (one case), and varicocele (two cases). Five examinations were performed with high-frequency probes (10/13 MHz) and seven with 5/7.5-MHz frequency transducers. Follow-up US examinations were performed at different times depending on initial clinical indications, presence of underlying disease, and initial US findings. Two of the six patients underwent three US examinations, two patients underwent two US examinations, and the remaining two patients underwent only one US examination. The patients underwent a total of 12 US examinations. Microliths were bilateral in four patients and unilateral in two patients. In these two latter cases, the contralateral testis was, in one case, cryptorchid and could not be evaluated by US; in the other case it was small and hyperechogenic with orchidopexy sequelae. In three cases microliths were distributed throughout the testis. In the remaining three cases they were present in limited areas of parenchyma. As to the importance of microliths, it was defined as mild in three cases and moderate/severe in three cases. Intratubular testicular microlithiasis is a well-proved histological finding (biopsy or autopsy). More recent is the US demonstration of TM with consequent definition of its pattern: usually bilateral hyperechogenic multiple small foci without acoustic shadows with complete or partial extension to the parenchyma. Testicular microlithiasis is a rare finding. Moreover, the pediatric cases reported in the literature are very few. However, the use of high-frequency US transducers (10–13 MHz) has recently allowed an easier demonstration of this disease also in children. Of particular interest is the study of the still-debated association of microliths with other diseases such as neoplasms. Some aspects need further investigation, namely the real incidence of microliths in the healthy population, the incidence of tumors in patients with microliths, the differences between adults and children, and the different types of follow-up at different ages. In pediatric age, if TM represents an isolated sign, patients need non-invasive US follow-up until adult age. Only if TM is in association with focal lesions of testis parenchyma is it mandatory to perform biopsy or surgical treatment. Received: 17 June 1998; Revision received: 26 August 1998; Accepted: 21 September 1998     

Diagnosis and temporal evolution of signs of intracranial hypotension on MRI of the brain

Introduction  A comprehensive evaluation of cranial magnetic resonance imagings (MRIs) of 23 patients with intracranial hypotension (IH) was performed, and the evolution of the abnormalities on follow-up MRIs was correlated with the clinical outcome. Materials and methods  The MRI report database at the University Health Network in Toronto was searched, and 23 cases of IH were identified between 2001 and 2007. A retrospective review of the MRIs of the brain and the electronic patient chart was performed. A control group of 40 subjects was also selected to complement the analysis of the pituitary gland. Results  A positive venous distention sign (VDS) was observed in 23 out of 23 patients and was the first sign to disappear on early follow-up scans following successful treatment. Pachymeningeal enhancement was seen in 23 out of 23 patients, and pachymeningeal thickening was detectable on unenhanced fluid attenuation inversion recovery (FLAIR) sequences in 17 out of 23 patients (74%). An increase in pituitary size in IH was also demonstrated based on the measured pituitary height and was qualitatively detectable in 12 out of 21 (57%) patients as the protrusion of the pituitary gland above the sella turica (two postpartum patients were excluded from this analysis). Overall, there was good correlation between the imaging findings and clinical outcome following treatment. Conclusion  Accurate diagnosis and follow-up of IH should be possible is some patients on unenhanced MRI of the brain by combining the signs on FLAIR and sagittal T1W images, enabling timely diagnosis in unsuspected cases and avoiding unnecessary administration of gadolinium compounds. In addition, VDS might be useful for early assessment of response to treatment.     

Detection of cerebrospinal fluid leakage in intracranial hypotension with radionuclide cisternography and blood activity monitoring

Radionuclide cisternography is an indispensable examination to detect cerebrospinal fluid (CSF) leakage in patients suspected of having spontaneous intracranial hypotension (SIH). However, it sometimes fails to demonstrate the site of CSF leakage, and in such cases, early bladder visualization is utilized for the diagnosis of SIH as an indirect finding. The aim of this work is to improve the diagnostic ability of radionuclide cisternography and to reevaluate the reliability of early bladder visualization as an indirect finding of CSF leakage. METHODS: We obtained serial images during the first hour after injection as well as the following time points in 4 patients with SIH and 5 with normal pressure hydrocephalus (NPH) as a control. We also performed blood sampling over time to measure blood radioactivity concentrations. RESULTS: All 4 patients with SIH demonstrated leakage, 2 of 4 within one hour after injection. Bladder visualization was observed falsely in 4 of 5 patients with NPH, considered to be the result of a lumbar puncture complication. In this false bladder visualization, blood radioactivity showed a more rapid raise and fall than in CSF leakage of SIH. CONCLUSIONS: The combination of radionuclide cisternography, including early time points and blood sampling, may enable accurate diagnosis of SIH.     

Juxtacortical chondromyxoid fibroma: imaging findings in three cases and a review of the literature

Chondromyxoid fibroma is a rare bone neoplasm characterized by chondral, myxoid and fibrous differentiation. Uncommon locations include the bone surface. Roentgenography, MRI and ultrasound can suggest the diagnosis. However, diagnosis of chondromyxoid fibroma is rarely made prior to biopsy. We present the radiologic and pathologic findings in three patients with this tumor and a review of the literature.     

低颅压综合征的临床特点与MRI表现

目的:分析14例低颅压综合征的临床特点及其MRI表现。方法:回顾性分析14例低颅压综合征患者的临床及MRI资料。结果:所有患者均有特征性体位性头痛;特征性MRI表现为7(7/8)例显示硬脑膜增厚,8(8/8)例显示窦汇扩张(后下缘后凸呈弧形),7(7/8)例显示双侧硬脑膜弥漫性对称性均匀性强化,10(10/14)例MRM示脊膜憩室、囊肿、脑脊液漏。结论:低颅压综合征的临床特点多样,体位性头痛是其特征性症状;头颅MRI增强扫描具有特征性表现,MRM可较为明确的显示脑脊液漏的部位;MRI检查在低颅压综合征的诊断中具有较大应用价值。