Unusual MRI abnormality in patients with nonketotic hyperglycaemia-associated seizures.

Nonketotic hyperglycaemia (NKH) is a metabolic disorder typically observed in individuals with inadequately managed or undiagnosed diabetes mellitus (DM). Seizures are a common clinical presentation in NKH, and they tend to respond better to glucose correction than anticonvulsant therapy. MRI scans may reveal both subcortical T2/fluid-attenuated inversion recovery (FLAIR) imaging hypointensity and cortical changes, including cortical grey matter T2/FLAIR imaging hyperintensity and cortical or leptomeningeal enhancement, although cortical abnormalities are less frequently observed. These alterations are reversible when the underlying metabolic disturbance is effectively addressed. We suggest the role of iron accumulation as a mechanism for subcortical T2 hypointensity using T2* weighted imaging. Our cases substantiate the significance of subcortical T2/FLAIR hypointensity as a fundamental feature of this condition. In the appropriate clinical context, the recognition of these MRI abnormalities can help prevent misdiagnosis and facilitate timely treatment.

Apocrine Adenoma of the Breast Showing Unique Image Findings.

Introduction: Apocrine adenoma of the breast is extremely rare and its typical images remain uncertain. Case Presentation: A 66-year-old woman was incidentally found of her left breast tumor with computed tomography for ascending colon cancer staging work. Mammography showed a well-demarcated oval mass. Ultrasonography showed an oval mass with indistinct borders, internal iso-echoes with multiple high echo spots, and unchanged posterior echoes. Magnetic resonance imaging of the mass showed a hypo-intense pattern both on T1- and T2-weighted images and a long-lasting rim enhancement pattern up to the late phase on time-signal intensity images. Probably due to the inappropriate tissue sampling, no definitive pathological diagnosis was obtained with core needle biopsy, forcing us to do lumpectomy of the breast mass at the time of colon cancer surgery. The resected breast mass was hard, clearly demarcated, and 8 mm in size. Cut surface of the mass was flesh-colored and had multiple white spots. Pathological study showed dense predominantly oval glandular ducts with luminal apocrine cell layers, outer myoepithelium cell layers, and slight fibrosis. Glandular cavities on pathology well matched to the white spots on macroscopic view, seemed vacant in a cyst-like fashion, and had aggregated foamy histiocytes in some of them. These pathological findings led us to the diagnosis of apocrine adenoma of the breast. Conclusion: Diagnostic physicians should note this extremely rare breast disorder and its image findings.

The Dark side of the White Matter. Diffuse subcortical White Matter Hypointensity on T2/FLAIR: A systematic review of a frequently underrecognized sign.

BACKGROUND AND OBJECTIVES: Many reversible brain MRI abnormalities have been described, among these the most frequently reported are cortical hyperintensities on FLAIR/T2 occurring during seizures. Much less attention has been given to those situations where White Matter goes Dark: subcortical white matter hypointensity on T2/FLAIR. Our aim is to identify the medical condition "Dark White Matter" (DWM) is more frequently associated with. This is the first systematic review on DWM. METHODS: PubMed was searched in August 2023. Included studies were those reporting Diffuse Subcortical White Matter Hypointensity on T2/FLAIR. Mainly case reports were included. Individual patient-level data was included whenever available. Frequency measures of the different diseases were calculated. RESULTS: 56 studies were included, 228 patients were eligible for analysis. DWM happened in isolation, with no cortical abnormalities, in 71 cases and was associated with seizures in >61.4% of cases. The most frequently DWM-associated disease was Non-Ketotic Hyperglycaemic hyperosmolar state (NKH), followed by Encephalitis, Moyamoya disease, Genetic Causes, and Subdural Hematoma. Frequency of NKH was 32%. NKH was associated with seizures in 100% of cases and the most frequently involved lobe was the occipital one. When considering only the subgroup of patients with seizures, DWM was indicative of NKH in 51.4% of cases and Encephalitis in 26.4% of cases. Key limitations are heterogeneity and missing data. DISCUSSION: DWM is frequently underdiagnosed. This sign can exist alone and it is not merely a consequence of cortical involvement. Moreover, it has important implications, both diagnostic and therapeutic, as it is more frequently associated with NKH, especially in the context of seizures, where anti-seizure medication is not the first line of treatment. We also discuss the pathogenesis of DWM by finding a common link between the most frequently associated diseases.

MRI Features for Predicting Microvascular Invasion and Postoperative Recurrence in Hepatocellular Carcinoma Without Peritumoral Hypointensity.

Purpose: To identify MRI features of hepatocellular carcinoma (HCC) that predict microvascular invasion (MVI) and postoperative intrahepatic recurrence in patients without peritumoral hepatobiliary phase (HBP) hypointensity. Patients and Methods: One hundred and thirty patients with HCC who underwent preoperative gadoxetate-enhanced MRI and curative hepatic resection were retrospectively reviewed. Two radiologists reviewed all preoperative MR images and assessed the radiological features of HCCs. The ability of peritumoral HBP hypointensity to identify MVI and intrahepatic recurrence was analyzed. We then assessed the MRI features of HCC that predicted the MVI and intrahepatic recurrence-free survival (RFS) in the subgroup without peritumoral HBP hypointensity. Finally, a two-step flowchart was constructed to assist in clinical decision-making. Results: Peritumoral HBP hypointensity (odds ratio, 3.019; 95% confidence interval: 1.071-8.512; P=0.037) was an independent predictor of MVI. The sensitivity, specificity, positive predictive value, negative predictive value, and AUROC of peritumoral HBP hypointensity in predicting MVI were 23.80%, 91.04%, 71.23%, 55.96%, and 0.574, respectively. Intrahepatic RFS was significantly shorter in patients with peritumoral HBP hypointensity (P<0.001). In patients without peritumoral HBP hypointensity, the only significant difference between MVI-positive and MVI-negative HCCs was the presence of a radiological capsule (P=0.038). Satellite nodule was an independent risk factor for intrahepatic RFS (hazard ratio,3.324; 95% CI: 1.733-6.378; P<0.001). The high-risk HCC detection rate was significantly higher when using the two-step flowchart that incorporated peritumoral HBP hypointensity and satellite nodule than when using peritumoral HBP hypointensity alone (P<0.001). Conclusion: In patients without peritumoral HBP hypointensity, a radiological capsule is useful for identifying MVI and satellite nodule is an independent risk factor for intrahepatic RFS.

Prognostic value of baseline MRI features in patients treated with thermal ablation for hepatocellular carcinoma.

PURPOSE: To investigate prognostic value of baseline MRI features for time-to-recurrence (TTR) and local recurrence in patients with early hepatocellular carcinoma (HCC). METHOD: Baseline and follow-up images of 88 patients treated with thermal ablation followed by adjuvant sorafenib or matching placebo due to HCC within the phase II prospective randomized trial (SORAMIC) were included. Baseline MRI images were evaluated in terms of atypical enhancement (lack of wash-in or wash-out), lesion diameter, tumor capsule, peritumoral enhancement on arterial phase, intratumoral fat, irregular margin, satellite lesions, and peritumoral hypointensity on hepatobiliary phase. Prognostic value of these features for TTR and local recurrence were assessed with univariable and multivariable Cox proportional hazard models. RESULTS: Recurrence at any location was diagnosed during follow-up in 30 patients, and the median TTR was 16.4 (95% CI, 15 - NA) months. The presence of more than one lesion (p = 0.028) and peritumoral hypointensity on hepatobiliary phase images (p = 0.012) at baseline were significantly associated with shorter TTR in univariable analysis. AFP > 15 mg/dL (p = 0.084), and history of cirrhosis (p = 0.099) were marginally non-significant. Peritumoral hypointensity on hepatobiliary phase images was the only significant risk factor for recurrence in multivariable analysis (p = 0.003). Local recurrence (adjacent to thermal scar) was diagnosed in eleven (8.3%) out of 132 lesions that underwent thermal ablation. The only significant risk factor for local recurrence was a lesion diameter larger than 3 cm (22.2% vs. 4.5%, p = 0.007). CONCLUSIONS: Peritumoral hypointensity on hepatobiliary phase can serve as imaging biomarker to identify increased recurrence risk in patients undergoing thermal ablation for early-stage HCC.

Location-atypical lesions in non-ketotic hyperglycemic epilepsy: expanding the clinico-radiographic phenotype

Non-ketotic hyperglycemia (NKH) is associated with a spectrum of symptoms and radiographic findings due to poorly-controlled diabetes mellitus. These lesions, which predominantly affect the parieto-occipital cortex, are commonly missed by neurologists and neuroradiologists due to their subtle hypointense appearance on T2-based imaging. We report four atypical cases of this syndrome to highlight its subtle, protean presentation in order to aid timely diagnosis. Based on our institutional case series, we describe four cases of NKH with atypical presentation and lesion burden affecting the anterior cortex. We review the clinical presentations, laboratory abnormalities, neuroimaging, and corresponding electroencephalography. Four patients with atypical NKH were characterized in our series. Presenting symptoms ranged from rhythmic hand-tapping to generalized tonic-clonic status epilepticus. Laboratory values were notable for marked hyperglycemia (range: 447 - 627 mg/dL), mild pseudo-hyponatremia (range: 127 - 136 mmol/L), and elevated hemoglobin A1C levels (range: 10.9 - 16.1%). All patients were found to have the classically described pattern of T2-based hypointensity; three with atypical distributions involving the "anterior" cortex. These lesions corresponded to the electrographic nidus of seizure burden. During follow-up, both seizures and T2-based hypointensity resolved within weeks of serum glucose normalization. Our series of four NKH patients with atypical findings of T2-based signal abnormalities expands the clinico-radiographic phenotype revealing a more protean distribution than previously described. Knowledge of these atypical imaging features will aid both the neurologist and radiologist in timely diagnosis and care of these patients.

Occipital Seizures and Persistent Homonymous Hemianopia (HH) With MRI Subcortical T2 Hypointensity in a Newly Diagnosed Diabetic Patient.

Non-ketotic hyperglycemia (NKH) can often cause seizures. Although these are usually in the form of focal seizures, occipital seizures have also been reported in case reports. Patients may present with complaints ranging from blurred vision and bright lights to homonymous hemianopia (HH) in occipital seizures due to hyperglycemia. Seizures can often be brought under control in a short time with good glycemic control. Seizures associated with NKH may cause subcortical T2 hypointensity on MRI in the occipital lobes and occipital epileptiform discharges on the electroencephalogram. In this case study, we aim to present a newly diagnosed diabetes mellitus patient who had homonymous hemianopsia in his neurological examination, had imaging and electrophysiological findings consistent with his examination and clinical findings, was admitted 15 days after his symptoms started, and whose seizures could not be controlled by glucose regulation. In this context, we evaluated the literature and compared our case to other patients who required anti-seizure drugs, with the goal of emphasizing the need of early treatment in seizures caused by NKH.

Peritumoral Imaging Manifestations on Gd-EOB-DTPA-Enhanced MRI for Preoperative Prediction of Microvascular Invasion in Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis.

Purpose: The aim was to investigate the association between microvascular invasion (MVI) and the peritumoral imaging features of gadolinium ethoxybenzyl DTPA-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) in hepatocellular carcinoma (HCC). Methods: Up until Feb 24, 2022, the PubMed, Embase, and Cochrane Library databases were carefully searched for relevant material. The software packages utilized for this meta-analysis were Review Manager 5.4.1, Meta-DiSc 1.4, and Stata16.0. Summary results are presented as sensitivity (SEN), specificity (SPE), diagnostic odds ratios (DORs), area under the receiver operating characteristic curve (AUC), and 95% confidence interval (CI). The sources of heterogeneity were investigated using subgroup analysis. Results: An aggregate of nineteen articles were remembered for this meta-analysis: peritumoral enhancement on the arterial phase (AP) was described in 13 of these studies and peritumoral hypointensity on the hepatobiliary phase (HBP) in all 19 studies. The SEN, SPE, DOR, and AUC of the 13 investigations on peritumoral enhancement on AP were 0.59 (95% CI, 0.41-0.58), 0.80 (95% CI, 0.75-0.85), 4 (95% CI, 3-6), and 0.73 (95% CI, 0.69-0.77), respectively. The SEN, SPE, DOR, and AUC of 19 studies on peritumoral hypointensity on HBP were 0.55 (95% CI, 0.45-0.64), 0.87 (95% CI, 0.81-0.91), 8 (95% CI, 5-12), and 0.80 (95% CI, 0.76-0.83), respectively. The subgroup analysis of two imaging features identified ten and seven potential factors for heterogeneity, respectively. Conclusion: The results of peritumoral enhancement on the AP and peritumoral hypointensity on HBP showed high SPE but low SEN. This indicates that the peritumoral imaging features on Gd-EOB-DTPA-enhanced MRI can be used as a noninvasive, excluded diagnosis for predicting hepatic MVI in HCC preoperatively. Moreover, the results of this analysis should be updated when additional data become available. Additionally, in the future, how to improve its SEN will be a new research direction.

Epileptic manifestations, pathophysiology, and imaging characteristics of non-ketotic hyperglycaemia: a review of the literature and a report of two cases with irreversible cortical vision loss.

The purpose of this review is to create more awareness regarding the epileptic manifestations of non-ketotic hyperglycaemia, which are not widely recognised, and to assist understanding of the pathophysiology involved. Given that type II diabetes is one of the common causes of morbidity worldwide, it is important to appreciate the various neurological manifestations of non-ketotic hyperglycaemia.Here, I present two cases and review the existing literature. Both patients developed irreversible vision loss, which is a novel finding because only transient visual defects have previously been reported. The review includes a detailed discussion of the pathophysiology and characteristic magnetic resonance imaging (MRI) findings of patients with defects in cerebral lobar regions, which were associated with a variety of clinical manifestations. These manifestations can be ascribed to epileptic phenomena involving various parts of the cerebrum.Hyperglycaemia can lead to the irreversible loss of vision. Early diagnosis and treatment on the basis of the clinical features and characteristic MRI findings are important to avoid an epilepsia partialis continua-like state and irreversible visual impairment.

Diagnostic performance of imaging features in the HBP of gadoxetate disodium-enhanced MRI for microvascular invasion in hepatocellular carcinoma: a meta-analysis.

BACKGROUND: Microvascular invasion (MVI) is a major risk factor for early recurrence in patients with hepatocellular carcinoma (HCC). Preoperative accurate evaluation of the presence of MVI could enormously benefit its treatment and prognosis. PURPOSE: To evaluate and compare the diagnostic performance of two imaging features (non-smooth tumor margin and peritumor hypointensity) in the hepatobiliary phase (HBP) to preoperatively diagnose the presence of MVI in HCC. MATERIAL AND METHODS: Original articles were collected from Medline/PubMed, Web of Science, EMBASE, and the Cochrane Library up to 17 January 2021 linked to gadoxetate disodium-enhanced magnetic resonance imaging (MRI) on 1.5 or 3.0 T. The pooled sensitivity, specificity, and summary area under the receiver operating characteristic curve (AUC) were calculated and meta-regression analyses were performed. RESULTS: A total of 14 original articles involving 2193 HCCs were included. The pooled sensitivity and specificity of non-smooth tumor margin and peritumor hypointensity were 73% and 61%, and 43% and 90%, respectively, for the diagnosis of MVI in HCC. The summary AUC of non-smooth tumor margin (0.74) was comparable to that of peritumor hypointensity (0.76) (z = 0.693, P = 0.488). The meta-regression analysis identified four covariates as possible sources of heterogeneity: average size; time interval between index test and reference test; blindness to index test during reference test; and risk of bias score. CONCLUSION: This meta-analysis showed moderate and comparable accuracy for predicting MVI in HCC using either non-smooth tumor margin or peritumor hypointensity in HBP. Four discovered covariates accounted for the heterogeneity.

Temporal subcortical T2 hypointensity on MRI in epilepsia partialis continua, a non ketotic hyperglycemia rather than herpes encephalitis.

PURPOSE: Hyperglycemia can present as many neurological problems, one of them is seizure. Different brain MRI features can be seen in focal seizures associated with nonketotic hyperglycemia that subcortical T2 hypointensity is the only characteristic one. Finding this MRI feature is highly valuable in early diagnosis and treatment. METHODS: Our patient was a 60-year-old female, a case of type 2 diabetes mellitus. She was brought to Emergency Room (ER) with focal colonic status epilepticus of right face and arm associated with confusion and drowsiness progressed over 2 weeks prior to admission. At first, acyclovir was started alongside anti-seizure medication with doubt of herpes encephalitis but antiviral was discontinued after normal LP result and characteristic MRI features. RESULTS: Subcortical T2 hypointensity in left temporal and insular lobe was seen on first MRI that was resolved on follow up MRI after she was treated. CONCLUSION: Epilepsia partialis continua in the setting of non ketotic hyperglycemia should be differentiated from that in herpes encephalitis in a diabetic patient presenting with subacute confusional state and focal status epilepticus considering characteristic MRI finding of subcortical T2 hypointensity.

Quantitative clinical and radiological recovery in post-operative patients with superficial siderosis by an iron chelator.

BACKGROUND: Superficial siderosis is a rare neurodegenerative disease caused by hemosiderin deposition on the brain surface. Although the efficacy of the iron chelator-deferiprone-in superficial siderosis has recently been documented, a comparative study of patients who underwent surgical ablation of their bleeding source and subsequently received treatment with or without deferiprone has not yet been conducted. METHODS: Fifteen postoperative patients with superficial siderosis were recruited, and seven patients were administered deferiprone (combination therapy group). Quantitative changes in the hypointense signals on T2*-weighted magnetic resonance images were acquired; additionally, cerebellar ataxia was assessed (International Cooperative Ataxia Rating Scale score and Scale for the Assessment and Rating of Ataxia). Audiometry was performed and the results were compared with those of patients who did not receive deferiprone (surgical treatment group; controls). RESULTS: Significant improvements in signal contrast ratios were noted in the lateral orbitofrontal gyrus, superior temporal lobe, insular lobe, brainstem, lingual gyrus, and cerebellar lobe in the combination therapy group. The scores of patients in the combination therapy group on the cerebellar ataxia scales significantly improved. The degree of signal improvement in the cerebellar lobe correlated with the improvement of cerebellar ataxia scores. Early deferiprone administration after disease onset and long-term administration were correlated with greater signal improvements on magnetic resonance imaging. No adverse effects were observed in the clinical or laboratory parameters. CONCLUSIONS: Deferiprone administration significantly improved radiological and clinical outcomes in patients with postoperative superficial siderosis. Earlier and longer courses of deferiprone could result in better patient prognosis.

Incidental evidence of hypointensity in brain grey nuclei on routine MR imaging: when to suspect a neurodegenerative disorder?

Deep grey nuclei of the human brain accumulate minerals both in aging and in several neurodegenerative diseases. Mineral deposition produces a shortening of the transverse relaxation time which causes hypointensity on magnetic resonance (MR) imaging. The physician often has difficulties in determining whether the incidental hypointensity of grey nuclei seen on MR images is related to aging or neurodegenerative pathology. We investigated the hypointensity patterns in globus pallidus, putamen, caudate nucleus, thalamus and dentate nucleus of 217 healthy subjects (ages, 20-79 years; men/women, 104/113) using 3T MR imaging. Hypointensity was detected more frequently in globus pallidus (35.5%) than in dentate nucleus (32.7%) and putamen (7.8%). A consistent effect of aging on hypointensity (p < 0.001) of these grey nuclei was evident. Putaminal hypointensity appeared only in elderly subjects whereas we did not find hypointensity in the caudate nucleus and thalamus of any subject. In conclusion, the evidence of hypointensity in the caudate nucleus and thalamus at any age or hypointensity in the putamen seen in young subjects should prompt the clinician to consider a neurodegenerative disease.

Diffusion- and Susceptibility Weighted Imaging Mismatch Correlates With Collateral Circulation and Prognosis After Middle Cerebral Artery M1-Segment Occlusion.

Objective: To explore the relation between diffusion-weighted and susceptibility weighted imaging (DWI-SWI) mismatch and collateral circulation or prognosis in patients with occluded M1 segments of middle cerebral artery (MCA). Methods: We enrolled 59 patients with MCA M1-segment occlusion for a retrospective review of baseline clinical and imaging data. As markers of circulatory collaterals, prominent laterality of posterior (PLPCA) and anterior (PLACA) cerebral arteries on magnetic resonance angiography (MRA) studies and a hyperintense vessel sign (HVS) on T2 fluid-attenuated inversion recovery (FLAIR) images were collectively scored. The extent of acute cerebral infarction was then quantified on DWI, using the Alberta Stroke Program Early CT Score (DWI-ASPECTS). Hypointensity vessel sign prominence (PVS) was also evaluated by SWI and similarly scored (SWI-ASPECT) to calculate DWI-SWI mismatch [(DWI-ASPECTS) - (SWI-ASPECTS)], ranging from -10 to 10 points. Results: DWI-SWI mismatch showed significant associations with PLPCA, PLACA, HVS prominence, and collective collateral scores (all, p < 0.05). National Institutes of Health Stroke Scale (NIHSS), DWI-SWI mismatch, and DWI-ASPECTS also differed significantly according to patient prognosis (good vs. poor) after MCA M1-segment occlusion (p < 0.05). In binary logistic regression analyses, NIHSS and DWI-SWI mismatch emerged as independent prognostic factors (p < 0.05). Conclusions: Collateral circulation may be an important aspect of DWI-SWI mismatch, which in this study correlated with prognostic outcomes of MCA M1-segment occlusion.

Diagnosis of meningeal melanomatosis in a dog using magnetic resonance imaging and cerebrospinal fluid findings.

A 13-year-old spayed female Labrador Retriever was presented with severe progressive tetraparesis. The neuroanatomic localization was the C1-C5 spinal cord segments with brainstem or cranial nerve involvement. Magnetic resonance imaging revealed diffuse T1-weighted and T2-weighted hyperintense lesions with strong contrast enhancement spreading through meninges of the cervical spinal cord and the brain. Few small round areas showing T1-weighted hyperintensity and T2-weighted hypointensity were scattered within the lesions. Cerebrospinal fluid analysis revealed neoplastic round cells and possible melanocytes. Malignant melanoma was suspected. At necropsy, the brain and the entire spinal cord were covered with thick, dark membranous tissue. Based on histopathologic findings, a positive response against Melan-A, and no melanoma identified outside the central nervous system, primary meningeal melanomatosis was diagnosed.

Hypointense head and neck lesions on T2-weighted images: correlation with histopathologic findings.

PURPOSE: On T2-weighted images, most solid lesions exhibit nonspecific intermediate signal intensity, whereas most cystic lesions exhibit marked hyperintensity. In contrast, on T2-weighted images, a relatively small number of lesions exhibit hypointensity. This review aimed to differentiate, according to the histopathologic findings, head and neck lesions showing hypointensity on T2-weighted images. METHODS: In this review article, hypointense head and neck lesions on T2-weighted images are classified into the following nine categories: calcified or osseous lesions, granulomatous lesions, fibrous lesions, mucous- or proteincontaining lesions, hemosiderin-containing lesions, melanin-containing lesions, thyroglobulin-containing lesions, rapid blood flow, and air-filled spaces. CONCLUSION: Knowledge regarding hypointense head and neck lesions on T2-weighted images allows radiologists to make accurate differential diagnoses. Key points • Hypointense head and neck lesions on T2-weighted images include calcified or osseous lesions, granulomatous lesions, fibrous lesions, mucous- or protein-containing lesions, hemosiderin-containing lesions, melanin-containing lesions, thyroglobulin-containing lesions, rapid blood flow, and air-filled spaces. • Radiologists should recognize the hypointense head and neck lesions on T2-weighted images for the final correct diagnosis, resulting in appropriate patient management.

Magnetic resonance imaging findings in patients with non-ketotic hyperglycaemia and focal seizures.

We present the neuroimaging findings of three cases of non-ketotic hyperglycaemia (NKH) associated with focal seizures and a review of the previous cases and series reported in literature. NKH is a cause of seizures in both long-standing and newly diagnosed diabetic patients. They are usually focal motor seizures, rarely with a secondary generalisation. This condition does not fully respond to anticonvulsant therapy if glycaemic levels are not normalised. Of interest, magnetic resonance imaging (MRI) of NKH could be different from those observed during other kinds of seizures. Indeed, seizure-related MRI abnormalities mainly involve the cortical grey matter, while NKH-related seizures usually appear as reversible subcortical T2/fluid attenuation inversion recovery (FLAIR) hypointensity. This latter abnormality shows a good spatial correlation with the area of the ictal focus on electroencephalogram and could be associated with other more common post-ictal MRI changes (cortical grey matter T2/FLAIR hyperintensity, cortical or leptomeningeal enhancement). Although these abnormalities tend to be transient, a focal volume loss or gliosis can result on follow-up imaging. Our cases confirm T2/FLAIR subcortical hypointensity as a main neuroradiological hallmark of NKH-induced seizures.

A practical predictor of the growth potential of benign meningiomas: Hypointensity of surface layer in T2-weighted magnetic resonance imaging.

BACKGROUND: Accurate evaluation of proliferative potential is particularly important in the clinical management of individual patients with meningiomas. We introduce a new feature in the parenchyma of meningioma, namely, hypointensity of the surface layer (HSL), on T2-weighted MR images and compare it with a cellular proliferation index and growth speed. MATERIALS AND METHODS: We retrospectively analyzed the records of consecutive patients with WHO grade I meningiomas in two institutes: an operated group with 124 meningiomas resected in one institute, and an observed group with 89 meningiomas monitored without surgery in the other. Proliferative potential was evaluated using the MIB-1 labeling index (MIB-1 LI) for the operated group and using the relative growth rate on serial MR images for the observed group. RESULTS: In the operated group, 60 (48.4%) meningiomas exhibited HSL. HSL-positive meningiomas were significantly smaller in size and more often calcified than HSL-negative ones. Univariate analysis showed that HSL negativity, large size, no calcification, and surrounding brain edema were significantly associated with high MIB-1 LI (p < 0.05). Multivariate analysis demonstrated that only HSL was significantly related to MIB-1 LI (p = 0.001). HSL did not correlate with tumor recurrence after resection. In the observed group, 43 (48.3%) meningiomas exhibited HSL and they presented a significantly slow relative growth rate. CONCLUSIONS: HSL is a simple and new radiological feature indicative of low proliferative potential and a low risk of enlargement of meningiomas. The presence or absence of HSL may serve as a key parameter for the selection of aggressive treatment or active observation.