Boomerang sign: Clinical significance of transient lesion in splenium of corpus callosum

Transient signal abnormality in the splenium of corpus callosum on magnetic resonance imaging (MRI) is occasionally encountered in clinical practice. It has been reported in various clinical conditions apart from patients with epilepsy. We describe 4 patients with different etiologies presenting with signal changes in the splenium of corpus callosum. They were diagnosed as having progressive myoclonic epilepsy (case 1), localization-related epilepsy (case 2), hemicrania continua (case 3), and postinfectious parkinsonism (case 4). While three patients had complete involvement of the splenium on diffusion-weighted image (“boomerang sign”), the patient having hemicrania continua showed semilunar involvement (“mini-boomerang”) on T2-weighted and FLAIR image. All the cases had noncontiguous involvement of the splenium. We herein, discuss these cases with transient splenial involvement and stress that such patients do not need aggressive diagnostic and therapeutic interventions. An attempt has been made to review the literature regarding the pathophysiology, etiology, and outcome of such lesions.     

Focal lesions in the splenium of the corpus callosum in patients with epilepsy

Purpose:   A focal lesion in the splenium of the corpus callosum is a rare finding in patients with epilepsy. Intoxication with antiepileptic drugs, edema after generalized seizures, or a rapid change of antiepileptic drug levels have been proposed as possible mechanisms. The aim of the present study was to analyze the relationship between this lesion and possible etiologic factors.
Patients and methods:   We analyzed the magnetic resonance imaging (MRI) scans of 1,050 patients undergoing prolonged video-EEG (electroencephalography) monitoring and identified 24 patients with a focal lesion in the splenium of the corpus callosum. Twenty-four age- and gender-matched temporal lobe epilepsy patients without such a lesion served as a control group. We evaluated the following parameters for their possible etiologic significance: epilepsy syndrome, seizure types in medical history, seizure frequency during the past year prior to admission for prolonged video-EEG monitoring, localization of interictal spikes and ictal EEG patterns in patients with focal epilepsies as documented during prolonged video-EEG-monitoring, seizure types and seizure frequency during prolonged video-EEG monitoring, past as well as current antiepileptic medication, withdrawal of antiepileptic drugs during monitoring including duration of medication withdrawal, and finally drug levels above the therapeutic range.
Results :  The parameters analyzed showed no significant difference between the group of patients with focal lesions in the splenium of the corpus callosum and the control group.
Conclusion:   We could not identify a single etiologic factor responsible for the lesion in the splenium of the corpus callosum.     

Transient lesions of the splenium of the corpus callosum following rapid withdrawal of levetiracetam

Transient lesions of the splenium of the corpus callosum are characterized by MRI findings. The lesions are very rare, but significant from a clinical standpoint as differential diagnoses include serious conditions such as encephalitis, meningitis, and neuroleptic malignant syndrome. In addition, it is reported that some are attributed to the withdrawal of antiepileptic drugs. Here, we present a case of transient lesions of the splenium of the corpus callosum following rapid withdrawal of levetiracetam alone. To the best of our knowledge, this is the first report of such a case. Moreover, it is reported that cases of incidental transient lesions of the splenium of the corpus callosum are detected in Japan more often than in other countries, and as a result are prone to over‐triage. Taking this into consideration, in the event of transient lesions of the splenium of the corpus callosum, the utmost attention must be paid to clinical symptoms and history relating to any of the aforementioned serious conditions.     

A case of prosopometamorphopsia caused by infarction of the splenium of the corpus callosum and major forceps

ABSTRACT

An adult female complained of enlargement of right eyes in other people. Diffusion-weighted imaging detected an abnormal high-intensity area in the region from the splenium of the corpus callosum to the major forceps on the right side. The patient reported that right eyes appeared larger in size, which suggested prosopometamorphopsia. Adichotic listening test identified left-ear deficit. Acombination of prosopometamorphopsia and left-ear deficit was not identified in the reported patients. Prosopometamorphopsia in most of the reported patients included the eye as did that in our patient. This result suggested the importance of information on the eye in recognizing faces.     

胼胝体压部可逆性病变的MRI诊断与临床分析

目的探讨胼胝体压部(splenium of the corpus callosum,SCC)可逆性病变的MRI表现及临床特点。方法回顾性分析8例脑MRI表现为单纯胼胝体压部可逆性病变患者的临床和影像学资料。结果 8例患者的SCC可逆性病变均为继发性,原发病分别为脑内感染5例,肝豆状核变性、低血糖脑病及脑外伤各1例。8例患者均急性起病,临床表现为发热、头痛5例,急性意识障碍2例,肌张力增高2例,颈强2例,均符合原发病的临床表现。8例均行脑MRI检查,均表现为T1低或等信号,T2及FLAIR序列高信号,DWI高信号(提示细胞源性水肿),其中4例行增强扫描未见强化。8例患者均于临床症状好转或消失后复查MRI提示病灶消失。结论 SCC可逆性病变在多种疾病中均可出现,无该病变相关的特异性临床表现,MRI表现提示病灶为细胞源性水肿可能。     

Diffuse cerebral hypomyelination with cerebellar atrophy and hypoplasia of the corpus callosum

Three unrelated Japanese patients who presented with ataxia and mild mental retardation were examined in this study. Early development was normal in two patients and slightly delayed in one. All could walk independently, but were unstable due to cerebellar ataxia. They had mild intellectual retardation and displayed slow, progressive, and mild clinical courses. Two patients lost the ability to walk at 12 and 25 years of age. Brain MRI of the three patients revealed diffuse cerebral hypomyelination, moderate cerebellar cortical atrophy, and hypoplasia of the corpus callosum, which were seen in other diffuse hypomyelination syndrome. No known abnormalities were found in biochemical and genetic studies. Auditory brainstem responses and nerve conduction studies were normal. A definite diagnosis could not be made because of the lack of hypodontia, hypogonadism, cataracts, or basal ganglia atrophy. Based on common MRI findings and the relatively mild clinical courses, we believe that these patients may have another subset form of diffuse hypomyelination syndrome involving the cerebral white matter and cerebellum.     

Agraphia with reversible splenial corpus callosum lesion caused by hypoglycemia

Background

Neurological manifestations caused by hypoglycemia range from reversible focal deficits and transient encephalopathy to irreversible coma or death. Recently, high signal intensity lesions in the splenium of the corpus callosum on diffusion-weighted magnetic resonance imaging were reported in adults experiencing hypoglycemia. However, patients presenting with agraphia are rare.

Social cognition in individuals with agenesis of the corpus callosum

Past research has revealed that individuals with agenesis of the corpus callosum (ACC) have deficits in interhemispheric transfer, complex novel problem-solving, and the comprehension of paralinguistic aspects of language. Case studies and family reports also suggest problems in social cognition. The performance of 11 individuals with complete ACC and with normal intelligence was compared to that of 13 IQ- and age-matched controls on three measures of social cognition. Individuals with ACC were indistinguishable from controls on the Happé Theory of Mind Stories and the Adult Faux Pas Test, but performed significantly worse on various portions of the Thames Awareness of Social Inference Test (TASIT) involving interpretations of videotaped social vignettes. Further analysis of the TASIT indicated that individuals with ACC showed deficiency in the recognition of emotion, weakness in understanding paradoxical sarcasm, and particular difficulty interpreting textual versus visual social cues. These results suggest that the tendency for deficient social cognition in individuals with ACC stems from a combination of difficulty integrating information from multiple sources, using paralinguistic cues for emotion, and understanding nonliteral speech. Together, these deficits would contribute to a less robust theory of mind.     

胼胝体动静脉畸形的显微外科治疗

报告26例胼胝体AVM（其中1例多发）的27个病灶。5个位于膝部,4个位于体部.18个位于压部。供血动脉主要来自大脑前动脉的胼周动脉;其次是大脑后动脉的脉络膜后动脉等分支。24个AVM采用显微外科手术作了全部切除。术后能正常生活者达88.5％,无死亡,并对胼胝体AVM显微外科切除手术的体会进行了讨论。     

Comprehension of humor in primary agenesis of the corpus callosum

Individuals with agenesis of the corpus callosum (ACC) can, in some cases, perform normally on standardized intelligence tests. Nevertheless, recent studies suggest that individuals with ACC and normal IQ scores have deficits in domains of fluid and social intelligence. Anecdotal reports from families suggest diminished appreciation of the subtleties of social interactions, and deficits in the comprehension of jokes and stories. In this research, both the cartoon and narrative joke subtests of a humor test (developed by Brownell et al. [Brownell, H., Michel, D., Powelson, J., & Gardner, H. (1983). Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients. Brain and language, 18(1), 20-27] and Bihrle et al. [Bihrle, A. M., Brownell, H. H., Powelson, J. A., & Gardner, H. (1986). Comprehension of humorous and non-humorous materials by left and right brain-damaged patients. Brain and Cognition, 5(4), 399-411]) were given to 16 adults with complete ACC (all with IQs>80) and 31 controls of similar age and IQ. Individuals with ACC performed worse than controls on the narrative joke subtest (p<.025) when VIQ was controlled. However, on the cartoon subtest the two groups were not significantly different. Covarying age, forms of IQ, narrative memory, set-switching, and literal language comprehension did not substantially alter the group difference. However, covarying comprehension of nonliteral language and proverbs eliminated the difference, suggesting a common origin for the comprehension of jokes, nonliteral language, and proverbs, most likely related to capacity for understanding second-order meanings.     

遗传性痉挛性截瘫伴薄型胼胝体的临床特征

目的 探讨遗传性痉挛性截瘫伴薄型胼胝体（HSP-TCC）的临床特征。方法 对4例HSP-TCC患者的临床资料进行回顾性分析。结果 4例患者均于青少年起病，表现为智能低下，痉挛步态，双下肢痉挛，无力，腱反射亢进，病理征阳性，无感觉障碍，2例有共济失调及大小便障碍；1例有双上肢痉挛及肌肉萎缩，头颅MRI显示胼胝体变薄。结论 HSP-TCC的主要临床特征为青少年起病的痉挛性截瘫，智能低下，头颅MRI显示胼胝体变薄。     

胼胝体发育不良合并罕见颅内多发对称脂肪瘤1例报告及文献复习

胼胝体发育不良是一种先天性颅脑畸形,包括胼胝体不发育或发育不全,发病率（0．5～70）例／万,但胼胝体发育不良合并颅内多发脂肪瘤报道很少,现将作者在工作中遇到的1例报告如下并结合文献对其发病机制、临床特点、诊断进行讨论。     

Thickness profile generation for the corpus callosum using Laplace's equation

The corpus callosum facilitates communication between the cerebral hemispheres. Morphological abnormalities of the corpus callosum have been identified in numerous psychiatric and neurological disorders. To quantitatively analyze the thickness profile of the corpus callosum, we adapted an automatic thickness measurement method, which was originally used on magnetic resonance (MR) images of the cerebral cortex (Hutton et al. [ 2008 ]: NeuroImage 40:1701–10; Jones et al. [ 2002 ]: Hum Brain Mapp 11:12–32; Schmitt and Böhme [ 2002 ]: NeuroImage 16:1103–9; Yezzi and Prince [ 2003 ]: IEEE Trans Med Imaging 22:1332–9), to MR images of the corpus callosum. The thickness model was derived by computing a solution to Laplace's equation evaluated on callosal voxels. The streamlines from this solution form non‐overlapping, cross‐sectional contours the lengths of which are modeled as the callosal thickness. Apart from the semi‐automated segmentation and endpoint selection procedures, the method is fully automated, robust, and reproducible. We compared the Laplace method with the orthogonal projection technique previously published (Walterfang et al. [ 2009a ]: Psych Res Neuroimaging 173:77–82; Walterfang et al. [ 2008a ]: Br J Psychiatry 192:429–34; Walterfang et al. [ 2008b ]: Schizophr Res 103:1–10) on a cohort of 296 subjects, composed of 86 patients with chronic schizophrenia (CSZ), 110 individuals with first‐episode psychosis, 100 individuals at ultra‐high risk for psychosis (UHR; 27 of whom later developed psychosis, UHR‐P, and 73 who did not, UHR‐NP), and 55 control subjects (CTL). We report similar patterns of statistically significant differences in regional callosal thickness with respect to the comparisons CSZ vs. CTL, UHR vs. CTL, UHR‐P vs. UHR‐NP, and UHR vs. CTL. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc.     

Alexithymia and somatization in agenesis of the corpus callosum

Deficient communication between the cerebral hemispheres is one of several prevailing neurobiological explanations for alexithymia and has been strongly supported by research on patients with commissurotomy. We examined self-reported symptoms of alexithymia in adults with agenesis of the corpus callosum (AgCC), a condition characterized by more subtle reductions in interhemispheric transfer than in commissurotomy. Sixteen adults with AgCC and full-scale intelligence quotient >80 were compared with 15 neurotypical controls group-matched for age and intelligence score. The AgCC group endorsed greater difficulty identifying and describing feelings and more vague physical symptoms than controls but similar levels of emotional experience and emotional coping. This finding of impaired emotional interpretation with intact emotional experience is consistent with findings in callosotomy patients, implicating the critical role of the corpus callosum in cognitive dimensions of emotion processing. Further study of alexithymia in AgCC using task-based measures may help clarify the nature of this relationship.     

Simultaneous diffusion-weighted magnetic resonance images and brain blood perfusion scintigraphy for a transient lesion in the splenium of the corpus callosum

A transient lesion in the splenium of the corpus callosum is a rare disease and its pathogenesis is unclear. We performed simultaneous diffusion-weighted magnetic resonance images and brain blood perfusion scintigraphy for a transient lesion in the splenium of the corpus callosum. This transient lesion showed hyperintensity on the diffusion-weighted images and hypointensity on the apparent diffusion coefficient map. However, normal blood perfusion was observed on brain blood perfusion scintigraphy. Transient axonal or intramyelinic edema might be a cause of the transient lesion in the splenium of the corpus callosum.     

Apert's syndrome with occipital encephalocele and absence of corpus callosum

A case of Apert's syndrome with posterior (occipital) encephalocele and absence of corpus callosum is described. This is a rare combination. The mechanisms involved are discussed.