Peri-ictal pseudoprogression in patients with brain tumor

Post-ictal changes presenting as late pseudoprogression on MRI and PET in a patient with diffuse glioma: Case report and brief literature review

Following completion of adjuvant radiation and chemotherapy imaging surveillance forms a major role in the management of diffuse gliomas. The primary role of imaging is to detect recurrences earlier than clinical symptomatology. Magnetic resonance imaging (MRI) is considered the gold standard in follow-up protocols owing to better soft tissue delineation and multiparametric nature. True recurrence can often mimic treatment-related changes, it is of paramount importance to differentiate between the two entities as the clinical course is divergent. Addition of functional sequences like perfusion, spectroscopy and metabolic imaging can provide further details into the microenvironment. In equivocal cases, a follow-up short interval imaging might be obtained to settle the diagnostic dilemma. Here, we present a patient with diagnosis of recurrent oligodendroglioma treated with adjuvant chemoradiation, presenting with seizures five years post-completion of chemotherapy for recurrence. On MRI, subtle new onset gyral thickening of the left frontal region with mild increase in perfusion and patchy areas of raised choline. FET-PET (fluoro-ethyltyrosine) showed an increased tumour-to-white matter (T/Wm) ratio favouring tumour recurrence. Based on discussion in a multi-disciplinary joint clinic, short interval follow-up MRI was undertaken at two months showing decrease in gyral thickening and resolution of enhancing areas in left frontal lobe. Repeat imaging one year later demonstrated stable disease status without further new imaging findings. Given the changes resolving completely without any anti-tumoral intervention, we conclude this to be peri-ictal pseudoprogression, being the second such case described in India.

Postoperative disappearance of leptomeningeal enhancement around the brainstem in glioblastoma

PURPOSE

Leptomeningeal enhancement (LME) suggests leptomeningeal dissemination (LMD) of tumor cells, which is a complication of end-stage glioblastoma, and is associated with a poor prognosis. However, magnetic resonance imaging (MRI) occasionally indicates the disappearance of peri-brainstem LME after surgical resection of glioblastoma. Since preoperative LMD may affect treatment indications, we aimed to analyze the clinical significance of preoperative LME of the brainstem in glioblastoma.

METHODS

We retrospectively collected clinical and radiological data from consecutive patients with glioblastoma and preoperative LME of the brainstem, who were treated at our hospital between 2017 and 2020.

RESULTS

Among 112 patients with glioblastoma, nine (8%) showed preoperative LME of the brainstem. In comparison with tumors without LME, tumor size was significantly associated with the preoperative LME of the brainstem (p = 0.016). In addition, there was a trend toward significance for a relationship between deep tumor location and preoperative LME of the brainstem (p = 0.058). Notably, among six patients who underwent surgical resection for glioblastoma with LME of the brainstem, four showed significant radiological disappearance of the LME on postoperative MRI. This suggests that the LME did not result from LMD in these cases. Moreover, these four patients lived longer than would be expected from the presence of LMD. However, this LME disappearance was not observed after biopsy or chemoradiotherapy.

CONCLUSIONS

These findings suggest that preoperative LME does not necessarily indicate the presence of untreatable LMD; moreover, LME may disappear after surgical tumor resection. Thus, transient preoperative LME could be attributed to other mechanisms, including impaired venous flow due to intratumoral arteriovenous shunts, which can be resolved by reducing the tumor burden.

Comprehensive Update and Review of Clinical and Imaging Features of SMART Syndrome

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a delayed complication of cranial irradiation, with subacute onset of stroke-like symptoms including seizures, visual disturbance, speech impairment, unilateral hemianopsia, facial droop, and aphasia, often associated with migraine-type headache. The diagnostic criteria were initially proposed in 2006. However, the diagnosis of SMART syndrome is challenging because clinical symptoms and imaging features of SMART syndrome are indeterminate and overlap with tumor recurrence and other neurologic diseases, which may result in inappropriate clinical management and unnecessary invasive diagnostic procedures. Recently, various imaging features and treatment recommendations for SMART syndrome have been reported. Radiologists and clinicians should be familiar with updates on clinical and imaging features of this delayed radiation complication because recognition of this entity can facilitate proper clinical work-up and management. This review provides current updates and a comprehensive overview of the clinical and imaging features of SMART syndrome.

Tumor or not a tumor: Pitfalls and differential diagnosis in neuro-oncology

The majority of intracranial expansive lesions are tumors. However, a wide range of lesions can mimic neoplastic pathology. Differentiating pseudotumoral lesions from brain tumors is crucial to patient management. This article describes the most common intracranial pseudotumors, with a focus on the imaging features that serve as clues to detect pseudotumors.

Prognostic Factors of Stroke-Like Migraine Attacks after Radiation Therapy (SMART) Syndrome

BACKGROUND AND PURPOSE

Prognostic factors of stroke-like migraine attacks after radiation therapy (SMART) syndrome have not been fully explored. This study aimed to assess clinical and imaging features to predict the clinical outcome of SMART syndrome.

MATERIALS AND METHODS

We retrospectively reviewed the clinical manifestations and imaging findings of 20 patients with SMART syndrome (median age, 48 years; 5 women) from January 2016 to January 2020 at 4 medical centers. Patient demographics and MR imaging features at the time of diagnosis were reviewed. This cohort was divided into 2 groups based on the degree of clinical improvement (completely versus incompletely recovered). The numeric and categoric variables were compared as appropriate.

RESULTS

There were statistically significant differences between the completely recovered group (n = 11; median age, 44 years; 2 women) and the incompletely recovered group (n = 9; median age, 55 years; 3 women) in age, months of follow-up, and the presence of steroid treatment at diagnosis (P = .028, .002, and .01, respectively). Regarding MR imaging features, there were statistically significant differences in the presence of linear subcortical WM susceptibility abnormality, restricted diffusion, and subcortical WM edematous changes in the acute SMART region (3/11 versus 8/9, P = .01; 0/11 versus 4/9, P = .026; and 2/11 versus 7/9, P = .022, respectively). Follow-up MRIs showed persistent susceptibility abnormality (11/11) and subcortical WM edematous changes (9/9), with resolution of restricted diffusion (4/4).

CONCLUSIONS

Age, use of steroid treatment at the diagnosis of SMART syndrome, and MR imaging findings of abnormal susceptibility signal, restricted diffusion, and subcortical WM change in the acute SMART region can be prognostic factors in SMART syndrome.

Stroke-Like Migraine after Radiation Treatment Syndrome in Children with Cancer

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a symptom complex of transient neurological deficits, headache, and abnormal cortical contrast enhancement on brain MRI. Pathophysiology is unclear, but exposure to cranial radiation (RT) is a sine qua non. We report five children with SMART syndrome treated with RT therapy for medulloblastoma (n = 3), atypical teratoid rhabdoid tumor (n = 1), and pleomorphic xanthoastrocytoma (n = 1). Median age at tumor diagnosis was 9.4 years (range 5.1–14.7). Median follow-up from cancer diagnosis was 3.1 years (range 1.4–12.9). All patients had 54 Gy focal RT treatment and medulloblastoma children had additional 36 Gy craniospinal irradiation. Median time from the end of RT to first transient neurological deficit was 1 year (range 0.7–12.1). The median follow-up since first SMART episode was 0.6 years (range 0.3–2.6). Presenting symptoms included the gradual development of unilateral weakness (n = 4), non-fluent dysphasia (n = 1), somnolence (n = 1), and headaches (n = 3). Neurological deficits resolved within 30 minutes to 10 days. Transient cortical enhancement on magnetic resonance imaging (MRI) was confirmed in two children and was absent in the other three. Two children had a single and three had multiple episodes over the next few months. Two children with protracted symptoms responded to 3 days treatment with high dose intravenous methylprednisolone. Symptoms ultimately resolved in all patients. SMART syndrome is a rare disorder characterized by slow evolution of neurological deficits with variable abnormal cortical contrast enhancement. The use of steroids may improve symptoms and speed resolution.

Persistent Nontumoral High-Amino-Acid Uptake on Brain [11C]Methionine PET/CT in a Patient After Combined Glioma Treatment

ABSTRACT

A 44-year-old man after combined left temporal low-grade glioma treatment presented with daily multiple series of seizures. MRI demonstrated diffuse cortical swelling in the left frontal lobe with intensive gyral enhancement. PET with [11C]methionine (PET-MET) revealed increased radiotracer uptake strictly confined to the cortical ribbon of the left cerebral hemisphere, which persisted for 3 months. Tumor recurrence was suggested, and biopsy was performed. No evidence of recurrent tumor was found. During a 2-year follow-up, a diffuse gyral enhancement in the left hemisphere has persisted on MRI; PET has shown high [11C]methionine uptake in the left frontal and parietal cortex with gradual positive dynamics.

Perfusion imaging with arterial spin labeling (ASL)-MRI predicts malignant progression in low‑grade (WHO grade II) gliomas

PURPOSE

Predicting malignant progression of grade II gliomas would allow for earlier initiation of treatment. The hypothesis for this single-centre, case-control study was that the perfusion signal on ASL-MRI predicts such malignant progression in the following 12 months.

METHODS

Consecutive patients with the following criteria were included: ≥ 18 years, grade II glioma (biopsied or resected) and an ASL-MRI 6-12 months prior to malignant progression (cases) or stable disease (controls). Malignant progression was defined either radiologically (new T1w-contrast enhancement) or histologically (neurosurgical tissue sampling). Three controls were matched with each case. Some patients served as their own control by using earlier imaging. The ASL-MRIs were reviewed by two neuroradiologists and classified as positive (hyper-intense or iso-intense compared to cortical grey matter) or negative (hypo-intense). In patients with epilepsy, a neurologist reviewed clinicoradiological data to exclude peri-ictal pseudoprogression. The statistical analysis included diagnostic test properties, a Cohen's Kappa interrater reliability coefficient and stratification for previous radiotherapy.

RESULTS

Eleven cases (median age = 48, IQR = 43-50 years) and 33 controls (43, 27-50 years) were included. Malignant progression appeared at 37 months (median, IQR = 17-44) after first surgery. Thirty ASL-MRIs were assessed as negative and 14 as positive. None of the MRIs showed signs of peri-ictal pseudoprogression. ASL significantly predicted subsequent malignant progression (sensitivity = 73%; specificity = 82%; OR = 12; 95%-CI = 2.4-59.1; p = 0.002). The interrater reliability coefficient was 0.65. In stratified analysis, ASL-MRI predicted malignant progression both in patients with previous radiotherapy and in those without (Mantel-Haenszel test, p = 0.003).

CONCLUSION

Perfusion imaging with ASL-MRI can predict malignant progression within 12 months in patients with grade II glioma.

Late effects of cancer treatment: consequences for long-term brain cancer survivors

Late adverse effects of cancer treatments represent a significant source of morbidity and also financial hardship among brain tumor patients. These effects can be produced by direct neurologic damage of the tumor and its removal, and/or by complementary treatments such as chemotherapy and radiotherapy, either alone or combined. Notably, young adults are the critical population that faces major consequences because the early onset of the disease may affect their development and socioeconomic status. The spectrum of these late adverse effects is large and involves multiple domains. In this review we classify the main long-term adverse effects into 4 sections: CNS complications, peripheral nervous system complications, secondary neoplasms, and Economic impact. In addition, CNS main complications are divided into nonfocal and focal symptoms. Owing to all the secondary effects mentioned, it is essential for physicians to have a high level of clinical suspicion to prevent and provide early intervention to minimize their impact.

Stroke-Like Migraine Attacks after Radiation Therapy Syndrome: Clinical and Imaging Characteristics

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare, reversible phenomenon that occurs several years after radiotherapy in patients treated for intracranial neoplastic lesions. Patients typically present with symptoms of headache, seizures, and other focal neurologic deficits concerning for stroke or disease recurrence. In this report, we describe SMART syndrome in a 70-year-old male who developed a persistent right temporal headache, right-sided neck pain, and new-onset seizures 12 years after surgical resection of a temporal anaplastic ependymoma followed by irradiation. We present this case to highlight typical disease presentation, imaging characteristics, and important differential radiologic considerations. Recognition of this delayed complication of brain tumor radiation is paramount given its self-limited course and favorable response to conservative therapy and to avoid misinterpreting imaging findings as tumor recurrence.

Glioblastoma with brainstem leptomeningeal pseudoprogression following radiation therapy

In brain tumor patients, worsening of imaging findings in the first 6 months after surgical debulking and chemoradiation can occur in the absence of tumor growth, a phenomenon known as pseudoprogression. Awareness of pseudoprogression is important as it can lead to unnecessary additional changes in patient management. In this case, a patient with bilateral frontal glioblastoma presented with new post-treatment brainstem leptomeningeal enhancement which was distant from the original tumor site, concerning for disease progression. However, the patient was asymptomatic and correlation of leptomeningeal enhancement locations with radiation therapy dose maps revealed high doses at the affected site, supporting a diagnosis of treatment effect which was confirmed by resolution on follow-up imaging after treatment with steroids. Parenchymal pseudoprogression in brain tumor patients is well-documented, but worsening leptomeningeal enhancement following therapy may also represent treatment effects. If spatially remote leptomeningeal enhancement occurs, correlation with radiation dose maps may be useful in suggesting a diagnosis of treatment effect over tumor progression.

An exploration of the spectrum of peri-ictal MRI change; a comprehensive literature review

PURPOSE

The aim of this review was to identify published studies in the literature relating to ictal induced MRI change and to identify certain common themes, practical points for clinicians and areas for future research.

METHODS

We identified 96 articles that satisfied our inclusion criteria yielding 575 cases. All articles were analysed; number of subjects, spectrum of MRI and EEG change, aetiology, and follow-up (both clinical and imaging) were noted.

RESULTS

The most frequent imaging changes were restricted diffusion, T2-hyperintensity and reduced ADC values. The mesial temporal structures and neocortex were most commonly affected locations though subcortical structures like the thalamus and pulvinar were also described. Practical clinical points included; the development of PLEDS concordant with ictal imaging change was associated with worse clinical prognosis, patients with seizures due to symptomatic aetiology may be more likely to develop ictal related imaging change and follow up is vitally important to ensure that ictal related oedema is not misidentified as a mass lesion or conversely that a mass lesion is not misidentified as ictal related change.

CONCLUSION

Qualitative MRI studies have provided clinicians with useful in-vivo insights into the dynamic ictal neuronal environment. Changes are not only localised to the ictal focus but can be remote and irreversible. Small patient numbers varying study design and high numbers of symptomatic seizures makes comparison between studies problematic. Also there is possible microstructural quantitative MRI changes that are missed on qualitative MRI. There is a need for prospective quantitative MRI studies in patients with epilepsy peri-icatlly with a uniform period of follow up and comparison to control data.

Unusual case of recurrent SMART (stroke-like migraine attacks after radiation therapy) syndrome

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare delayed complication of cerebral radiation therapy. A 53-year-old female initially presented with headache, confusion and left homonymous hemianopia. Her medical history was notable for cerebellar hemangioblastoma, which was treated with radiation in 1987. Her initial brain MRI (magnetic resonance imaging) revealed cortical enhancement in the right temporo-parieto-occipital region. She improved spontaneously in 2 weeks and follow-up scan at 4 weeks revealed no residual enhancement or encephalomalacia. She presented 6 weeks later with aphasia. Her MRI brain revealed similar contrast-enhancing cortical lesion but on the left side. Repeat CSF studies was again negative other than elevated protein. She was treated conservatively and recovered completely within a week. Before diagnosing SMART syndrome, it is important to rule out tumor recurrence, encephalitis, posterior reversible encephalopathy syndrome (PRES) and stroke. Typically the condition is self-limiting, and gradually resolves.

Epileptic Activity Increases Cerebral Amino Acid Transport Assessed by 18F-Fluoroethyl-l-Tyrosine Amino Acid PET: A Potential Brain Tumor Mimic

O-(2-¹⁸F-fluoroethyl)-l-tyrosine (¹⁸F-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect ¹⁸F-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by ¹⁸F-FET PET and to elucidate the pathophysiologic background.

METHODS

Ten patients with 11 episodes of serial seizures or status epilepticus, who underwent MRI and ¹⁸F-FET PET, were studied. The main diagnosis was glioma World Health Organization grade II-IV (n = 8); 2 patients suffered from nonneoplastic diseases. Immunohistochemical assessment of LAT1/LAT2/CD98 amino acid transporters was performed in seizure-affected cortex (n = 2) and compared with glioma tissues (n = 3).

RESULTS

All patients exhibited increased seizure-associated strict gyral ¹⁸F-FET uptake, which was reversible in follow-up studies or negative shortly before and without any histologic or clinical signs of tumor recurrence. ¹⁸F-FET uptake corresponded to structural MRI changes, compatible with cortical vasogenic and cytotoxic edema, partial contrast enhancement, and hyperperfusion. Patients with prolonged postictal symptoms lasting up to 8 wk displayed intensive and widespread (≥ 1 lobe) cortical ¹⁸F-FET uptake. LAT1/LAT2/CD98 was strongly expressed in neurons and endothelium of seizure-affected brains and less in reactive astrocytosis.

CONCLUSION

Seizure activity, in particular status epilepticus, increases cerebral amino acid transport with a strict gyral ¹⁸F-FET uptake pattern. Such periictal pseudoprogression represents a potential pitfall of ¹⁸F-FET PET and may mimic brain tumor. Our data also indicate a seizure-induced upregulation of neuronal, endothelial, and less astroglial LAT1/LAT2/CD98 amino acid transporter expression.

Postictal Magnetic Resonance Imaging Changes Masquerading as Brain Tumor Progression: A Case Series

Seizures are common among patients with brain tumors. Transient, postictal magnetic resonance imaging abnormalities are a long recognized phenomenon. However, these radiographic changes are not as well studied in the brain tumor population. Moreover, reversible neuroimaging abnormalities following seizure activity may be misinterpreted for tumor progression and could consequently result in unnecessary tumor-directed treatment. Here, we describe two cases of patients with brain tumors who developed peri-ictal pseudoprogression and review the relevant literature.

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is not always completely reversible: a case series

We retrospectively reviewed clinical and imaging findings in 11 patients with stroke-like migraine attacks after radiation therapy (SMART) syndrome to better understand this disorder previously thought to be reversible. Six men and 5 women had complex bouts of neurologic impairment beginning, on average, 20 years after cerebral irradiation. All had characteristic, unilateral gyriform enhancement on MR imaging that developed within 2-7 days and typically resolved in 2-5 weeks. Unlike prior reports, 45% had incomplete neurologic recovery manifesting as dysphasia, cognitive impairment, or hemiparesis. The remaining 55% recovered completely over an average of 2 months. Three of 11 patients developed cortical laminar necrosis. Brain biopsies in 4 of 11 did not demonstrate a specific pathologic substrate. These additional 11 patients contribute to the understanding of variability in stroke-like migraine attacks after radiation therapy syndrome, which often but not uniformly manifests with headaches and seizures, demonstrates a typical evolution of imaging findings, and may result in permanent neurologic and imaging sequelae.

Seizures during the management of high-grade gliomas: clinical relevance to disease progression

This study was performed to evaluate the incidence of seizures with its implications on disease progression and the diagnostic value of post-ictal magnetic resonance images (MRI) during the management of high-grade gliomas (HGGs). A total of 406 consecutive patients with newly diagnosed HGGs were retrospectively reviewed. The incidence of seizures during the management was investigated. In patients who experienced a seizure, the causality between seizures and disease progression was assessed by pre-ictal, post-ictal (<1 month), and follow-up (<3 months) MRI. After a median follow-up of 17.4 months (range 0.1-88.3), seizures developed in 127 patients (31 %). Of the 127 patients, radiological progression at the post-ictal MRI was found in 83 patients (65 %) and the follow-up MRI confirmed progression in 79 patients (62 %). Four other patients (3 %) were shown to be progression-free. Among those without radiological progression at the post-ictal MRI, the follow-up MRI confirmed progression-free in 31 patients (24 %); however, 13 patients (10 %) revealed eventual progression. In the patients with a seizure, absence of preoperative seizures (p = 0.003), <95 % tumor resection (p = 0.001), and pre-ictal Karnofsky Performance Scale score ≤ 70 (p = 0.025) were significantly associated with disease progression. During the management of HGG, 31 % of patients experienced seizures; of these patients, 72 % harbored progressive disease. The post-ictal MRI is useful for detecting disease progression; however, there are pitfalls. Clinical settings should be considered together for diagnosing disease progression in patients with seizures.

Pseudoprogression in high-grade glioma

Pseudoprogression is a treatment-related effect seen on imaging in high-grade glioma. Enhancement of gadolinium contrast on control MRI can be misinterpreted as tumor recurrence and is also difficult to distinguish from radiation necrosis. Pseudoprogression is seen in up to 30% after standard treatment for glioblastoma multiforme (GBM), which is radiotherapy concurrent with chemotherapy with temozolomide (TMZ) and adjuvant cycles of TMZ. In this article, the current literature on pseudoprogression in high-grade glioma is reviewed by searches in PubMed. We also present two clinical cases, one of which had medullary pseudoprogression. No articles on this subentity of pseudoprogression were found in PubMed. Standard MRI with gadolinium contrast cannot differentiate between pseudoprogression, tumor recurrence and radiation necrosis. More advanced imaging techniques are often not available. Pseudoprogression seems to be related to methylated promoter of the O(6)--methyl-guanine methyl transferase (MGMT) gene, which is associated with improved treatment effect. Discontinuation or change of therapy on the basis of misinterpretation of MRI as disease progression is thus unfortunate. MRI should be interpreted with caution the first 6 months after standard treatment of high-grade glioma. In a GBM patient with contrast enhancement on MRI but few or no new symptoms and/or stable steroid doses, treatment should be continued and control imaging performed after 2-3 months.