Modern techniques of magnetic resonance in the evaluation of primary central nervous system lymphoma: contributions to the diagnosis and differential diagnosis

Determine the factors affecting the time to recovery of children with bacterial meningitis at Jigjiga university referral hospital in the Somali Regional State of Ethiopia: using the parametric shared frailty and AFT models

BACKGROUND

Neisseria meningitides, Streptococcus pneumonia, and hemophilic influenza type B are frequently linked to bacterial meningitis (BM) in children. It's an infectious sickness that kills and severely mobilizes children. For a variety of reasons, bacterial meningitis remains a global public health concern; most cases and deaths are found in Sub-Saharan Africa, particularly in Ethiopia. Even though vaccination has made BM more preventable, children worldwide are still severely harmed by this serious illness. Age, sex, and co-morbidity are among the risk variables for BM that have been found. Therefore, the main objective of this study was to identify the variables influencing the time to recovery for children with bacterial meningitis at Jigjiga University referral hospital in the Somali regional state of Ethiopia.

METHOD

A retrospective cohort of 535 children with bacterial meningitis who received antibiotic treatment was the subject of this study. Parametric Shared Frailty ty and the AFT model were employed with log likelihood, BIC, and AIC methods of model selection. The frailty models all employed the patients' kebele as a clustering factor.

RESULTS

The number of cases of BM declined in young children during the duration of the 2 year, 11 month study period, but not in the elderly. Streptococcus pneumonia (50%), hemophilic influenza (30.5%), and Neisseria meningitides (15%) were the most frequent causes of BM. The time to recovery of patients from bacteria was significantly influenced by the covariates male patients (ϕ = 0.927; 95% CI (0.866, 0.984); p-value = 0.014), patients without a vaccination history (ϕ = 0.898; 95% CI (0.834, 0.965); P value = 0.0037), and patients who were not breastfeeding (ϕ = 0.616; 95% CI (0.404, 0.039); P-value = 0.024). The recovery times for male, non-breastfed children with bacterial patients are 7.9 and 48.4% shorter, respectively. In contrast to children with comorbidity, the recovery time for children without comorbidity increased by 8.7%.

CONCLUSION

Age group, sex, vaccination status, co-morbidity, breastfeeding, and medication regimen were the main determinant factors for the time to recovery of patients with bacterial meningitis. Patients with co-morbidities require the doctor at Jigjiga University Referral Hospital to pay close attention to them.

Intracranial myeloid sarcoma as the first presentation of acute myeloid leukemia and literature review

INTRODUCTION

Intracranial myeloid sarcoma is a rare extramedullary presentation of acute myeloid leukemia (AML). It can involve the meninges and ependyma presenting as extra-axial mass lesion. Rarely, it can also invade the brain parenchyma. It is commonly seen in children. It is usually misdiagnosed due to its close resemblance to other intracranial tumors (meningioma, metastasis, Ewing's sarcomas, and lymphoma). These are underdiagnosed if they precede the diagnosis of leukemia.

CASE REPORT

A 7-year-old boy with isolated intracranial myeloid sarcoma who presented with raised intracranial pressure (ICP) which was successfully managed by surgical excision.

CONCLUSION

Isolated intracranial myeloid sarcoma is a rare presentation of AML. Leukemia can be diagnosed early during the postoperative period and can be started on therapy timely. These patients requires regular follow-ups (clinical, laboratory and radiological) to detect relapses early.

Extra- and Intracranial Diffuse Large B-Cell Lymphoma (DLBCL) Mimicking Meningioma: A Case Report and Literature Review

Primary central nervous system lymphomas (PCNLSs) are malignant non-Hodgkin lymphomas solely affecting the central nervous system (CNS). Here, we present a rare case of extra- and intracranial manifestation without adjacent calvarial infiltration. We report a 67-year-old woman who presented with right leg paresis and hypoesthesia, facial hypoesthesia, focal epileptic seizures, and an indolent tumor on the left parietal scalp. MRI showed a left paramedian extra- and intracranial contrast-enhancing tumor with infiltration of the superior sagittal sinus, but without osseous infiltration on CT. The tumor was radiologically suspected to be a meningioma and resection was performed. Histological examination, however, revealed a diffuse large B-cell lymphoma (DLBCL). Thus, the patient received adjuvant treatment according to the MATRix protocol. We provide a detailed analysis of this rare case with a focus on preoperative radiological findings and differential diagnoses. To the best of our knowledge, this is one of only four published cases of DLBCL with extra- and intracranial manifestation without bone affection.

Dural lymphoma misdiagnosed as subdural hematoma following head trauma after an episode of syncope

Primary dural lymphoma is a rare subtype of primary central nervous system lymphoma. Primary dural lymphoma may be radiologically misdiagnosed as it shares similar imaging characteristics with several pathologies, including meningiomas and subdural or epidural hematomas. We present a patient who was originally diagnosed with a subdural hematoma following a syncopal episode on computed tomography. Follow-up magnetic resonance imaging of the brain demonstrated heterogeneously enhancing dural-based mass overlying the left frontoparietal convexity associated with bidirectional dural tails, suggestive of a malignant meningioma. Neurosurgical histopathology revealed marginal zone B-cell lymphoma. This case represents the potential difficulty in diagnosing primary dural lymphoma, especially in the setting of uncertain clinical history and obscured imaging features.

Advances in therapeutic strategies for primary CNS B-cell lymphomas

INTRODUCTION

Primary CNS lymphoma (PCNSL) has traditionally been treated with induction HD-MTX-based chemotherapy, followed by consolidation whole-brain radiotherapy. However, this approach is associated with significant neurocognitive complications, especially in older patients. Therefore, different consolidation protocols have been evaluated. High-dose chemotherapy followed by autologous stem cell transplantation (HD-ASCT) has the best long-term survival outcomes in younger patients.

AREAS COVERED

In this review of the literature, we focus on the overall therapeutic strategy and advances in the management of the aggressive primary CNS B-cell lymphomas.

EXPERT OPINION

In young and fit PCNSL patients, HD-ASCT is the preferred consolidation strategy to achieve long-term survivals. Older patients with good performance status should also be evaluated for MTX-based induction polychemotherapy followed by ASCT. However, management of PCNSL patients remains challenging, and new avenues with targeted therapies are under investigation. To date, ibrutinib, lenalidomide, and immune checkpoint inhibitors appearto be promising in PCNSL. However, as monotherapy, durable responses are less likely to be achieved. Unfortunately, when combined with chemoimmunotherapy, considerable toxicity and mortality have been reported. Clinical trials on these molecules are aiming to reduce toxicity and maintain responses. CAR-T-cell therapy has recently emerged as a further option. It has shown efficacy in patients with secondary CNS lymphoma, with few but encouraging results in primary CNSL.

Different facets of intracranial central nervous system lymphoma and its imaging mimics

Lymphomas of the central nervous system (CNS) are broadly classified into primary CNS lymphoma (PCNSL) and secondary CNS lymphoma (SCNSL). PCNSL refers to lymphoma restricted to the brain, leptomeninges, spinal cord, or eyes without evidence of it outside the CNS at primary diagnosis, while SCNSL refers to secondary CNS involvement by systemic lymphoma. The brain is the most common site of involvement and intracranial CNS lymphoma has a highly variable imaging appearance and varies according to the patient’s clinical profile and immunity. This pictorial essay aims to illustrate the different facets of intracranial CNS lymphomas on neuroimaging. This enables radiologists to be familiarized with their key diagnostic features and differentiate from their differential diagnoses, leading to early diagnosis, and treatment.

Diffuse Infiltrative Non-mass-like Brain Parenchymal Lesions on MRI: Differentiating Lymphomatosis Cerebri from its Mimics

Objectives:

Diffuse infiltrative “non-mass-like” parenchymal lesions on MRI brain are a known presentation of an aggressive condition called lymphomatosis cerebri (LC) but are often misdiagnosed due to its non-specific clinical and imaging findings. We aim to identify clues to differentiate lymphomatosis from its less aggressive mimics based on imaging features.

Material and Methods:

MRI brain studies showing diffuse infiltrative “non-mass-like” parenchymal lesions between January 2013 and March 2020 were retrospectively identified and read for lesion location, signal characteristics, and enhancement pattern by two radiologists. Additional findings on MRI spine and whole-body fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) were recorded wherever available. The clinical diagnosis, patient demographics, symptoms, laboratory and histopathology results, treatment details, and follow-up details were also noted.

Results:

Of the 67 patients, 28 (41.7%) were diagnosed with lymphomatosis. The remaining 39 (13.4%) patients were classified as non-lymphomas (infective, vasculitis, and inflammatory conditions). Diffusion restriction on MRI (20/67, P = 0.007) and increased regional activity on FDG PET-CT (12/31, P = 0.017) were the two imaging parameters found to significantly favor lymphomatosis over other conditions, whereas the presence of microhemorrhages on susceptibility-weighted imaging was significantly associated with vasculitis (P = 0.002). Rapid clinical or imaging deterioration on a short trial of steroids (P = 0.00) was the only relevant clinical factor to raise an early alarm of lymphomatosis. Positive serological markers and non-central nervous system systemic diseases were associated with non-lymphomatous diseases.

Conclusion:

LC and its less aggressive mimics can be differentiated on diffusion-weighted imaging-MRI and PET-CT when read in conjunction with rapid progression of clinical features, serological workup, and systemic evaluation.

Extra-axial tentorial medulloblastoma: a rare presentation of a common posterior fossa tumour

Medulloblastoma is a common paediatric posterior fossa tumour typically presenting as midline intra-axial mass involving the cerebellar vermis and/or roof of fourth ventricle with typical radiological features. These can be extra-axial in extremely rare instances with less than 50 cases reported so far in literature. We present a case of 18-year-old boy presenting with ataxia and headache. MRI showed dural mass (involving the left tentorium cerebellum) with typical imaging features of extra-axial lesion. The patient underwent near total excision of the tumour. Histopathology along with immunohistochemistry revealed the mass to be medulloblastoma. We present this case to highlight rarity of this location for medulloblastoma and the importance of considering this in the differential diagnosis of atypical posterior fossa extra-axial lesions. This can help in performing other relevant preoperative workup similar on the lines of medulloblastoma and planning of relevant management.

Positron emission tomography and magnetic resonance imaging in primary central nervous system lymphoma-a narrative review

This review addresses the challenges of primary central nervous system (CNS) lymphoma diagnosis, assessment of treatment response, and detection of recurrence. Primary CNS lymphoma is a rare form of extra-nodal non-Hodgkin lymphoma that can involve brain, spinal cord, leptomeninges, and eyes. Primary CNS lymphoma lesions are most commonly confined to the white matter or deep cerebral structures such as basal ganglia and deep periventricular regions. Contrast-enhanced magnetic resonance imaging (MRI) is the standard diagnostic modality employed by neuro-oncologists. MRI often shows common morphological features such as a single or multiple uniformly well-enhancing lesions without necrosis but with moderate surrounding edema. Other brain tumors or inflammatory processes can show similar radiological patterns, making differential diagnosis difficult. [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) has selected utility in cerebral lymphoma, especially in diagnosis. Primary CNS lymphoma can sometimes present with atypical findings on MRI and FDG PET, such as disseminated disease, non-enhancing or ring-like enhancing lesions. The complementary strengths of PET and MRI have led to the development of combined PET-MR systems, which in some cases may improve lesion characterization and detection. By highlighting active developments in this field, including advanced MRI sequences, novel radiotracers, and potential imaging biomarkers, we aim to spur interest in sophisticated imaging approaches.

MRI findings, including diffusion-weighted imaging, in seven cats with nasal lymphoma and two cats with nasal adenocarcinoma

OBJECTIVES

Primary nasal tumours in cats are rare, with lymphoma being the most common feline nasal tumour, followed by adenocarcinoma. Although CT can reliably detect feline nasal tumours, there are no specific CT features that identify each tumour type. To our knowledge, there have been no reports describing MRI findings, including diffusion-weighted imaging (DWI), for nasal lymphomas and adenocarcinomas in cats. Therefore, this retrospective study aimed to evaluate the MRI findings of nasal lymphoma and adenocarcinoma, including qualitative and quantitative analysis of DWI.

METHODS

MRI examination was performed on seven cats with histologically confirmed lymphoma and on two with adenocarcinoma. The MRI protocol included T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and DWI. Apparent diffusion coefficient (ADC) values were measured using DWI. Contrast agent was not used in one cat with lymphoma.

RESULTS

Of the cats with lymphoma, three (43%) were iso- and hyperintense on T2WI, seven (100%) were isointense on T1WI, five (83%) exhibited mild heterogeneous enhancement, including a prominent region of non-enhancement on post-contrast T1WI, and seven (100%) cats exhibited hyperintensity on DWI. The median ADC values were 0.45 × 10-3 mm2/s (range 0.37-0.53 × 10-3 mm2/s). For adenocarcinoma, two (100%) were iso- and hyperintense on T2WI, two (100%) were isointense on T1WI, two (100%) exhibited marked heterogeneous enhancement on post-contrast T1WI and two (100%) were isointense on DWI. The median ADC values were 1.08 × 10-3 mm2/s (range 0.88-1.27 × 10-3 mm2/s). The median ADC values of lymphoma tended to be lower than adenocarcinoma (P = 0.056).

CONCLUSIONS AND RELEVANCE

Determining ADC value and tumours with a large area of non-enhancement may be helpful in differentiating nasal lymphoma from nasal adenocarcinoma.

A comparative study of multimodal magnetic resonance in the differential diagnosis of acquired immune deficiency syndrome related primary central nervous system lymphoma and infection

Background

Patients with acquired immune deficiency syndrome (AIDS) often suffer from opportunistic infections and related primary central nervous system lymphoma (AR-PCNSL). Both diseases showed multiple ring enhancement lesions in conventional magnetic resonance (MR). It is very difficult to make the differential diagnosis. We aimed to investigate whether multimodal MR (diffusion weighted imaging (DWI)/ apparent diffusion coefficient (ADC), 3D pseudo-continuous arterial spin labeling (3D-pCASL) and susceptibility-weighted imaging (SWI)) combined with conventional MR can differentiate AR-PCNSL from infections.

Methods

This was a prospective study. We recruited 19 AIDS patients who were divided into AR-PCNSL group (9 cases) and infection group (10 cases) by pathological results. We analyzed whether there was statistical (Fisher’s method) difference in multimodal MR between the two groups. We analyzed whether multimodal MR combined with conventional MR could improve the diagnosis of AR-PCNSL.

Results

The lesions were more likely involved the paraventricular (0.020) and corpus callosum (0.033) in AR-PCNSL group in conventional MR. In multimodal MR, AR-PCNSL group showed low ADC value, with p values of 0.001. Infection group more inclined to high ADC value, with p was 0.003. In multimodal MR, AR-PCNSL group had more low signal intensity (grade 2–3) in the degree of intratumoral susceptibility signal intensity in SWI (SWI-ITSS), with p values of 0.001. The sensitivity, specificity of conventional MR in the diagnosis of AR-PCNSL was 88.9 and 70.0%. The conventional MR sequence combined with DWI/ADC sequence in the diagnosis of AR-PCNSL had a sensitivity of 100.0%, and a specificity of 60.0%. The sensitivity and specificity of the conventional MR sequence combined with the SWI-ITSS sequence in the diagnosis of AR-PCNSL were 100 and 70.0%. The conventional MR combined with ADC or SWI-ITSS improved the diagnosis of AR-PCNSL.

Conclusion

Multimodal MR could distinguish AR-PCNSL from infectious lesions. The multimodal MR (DWI/ADC or SWI-ITSS) combined with conventional MR could improve the diagnosis of AR-PCNSL. The ADC value should be attached importance in clinical work. When distinguishing AR-PCNSL from toxoplasmosis or tuberculoma, SWI should be used to obtain a correct diagnosis.

Isolated intracranial myeloid sarcoma: report of a case and review of the literature

Myeloid sarcoma is a rare malignant tumor of primitive myeloid cell origin often associated with hematologic disorders. The central nervous system is rarely involved and differentiating between myeloid sarcoma and other tumors is not possible on imaging. Here we present the rare case of an isolated intracranial myeloid sarcoma, initially misdiagnosed radiologically as a meningioma, treated with surgical total resection and subsequent chemotherapy, with no signs of any hematological disorder at follow up. Differential diagnosis and management strategies, as well as follow-up implications are discussed along with literature review, which pointed out that only five cases with no further signs of hematological disorders at follow up have been described in the literature so far and this case has the longest follow up of them at 9 years.

Less enhancement and low apparent diffusion coefficient value on magnetic resonance imaging may be helpful to detect canine prostate adenocarcinoma in case series

In dogs, diagnosis of prostate cancer is often delayed because clinical signs are not pathognomonic. Although ultrasonography is mainly performed to detect prostate cancer, the ultrasonographic appearance is not specific. In humans, magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) is used to localize the prostate tumour. To our knowledge, there are no studies of MRI findings for detecting or localizing prostate cancer. The purpose of this study was to assess MRI findings of prostate cancer. As a control, three prostate hyperplasia cases were included. MRI data were analysed, and the following parameters were noted: signal intensity (SI) of prostate lesion on T2-weighted imaging, T1-weighted imaging and DWI, enhancement pattern of prostate lesion, and relative contrast enhancement indices (RCEI) and apparent diffusion coefficient (ADC) value of prostate lesion. For MRI examination, the mean RCEI of the adenocarcinoma was significantly lower than that of hyperplasia (P = .01, r = .8). The SI of the DWI of adenocarcinoma was significantly higher compared to hyperplasia (P = .03, φ = 1). The mean ADC values of the adenocarcinoma were significantly lower than that of hyperplasia (P = .03, r = .82). Thus, less enhancement on MRI, and low ADC value on MRI may help to detect prostate adenocarcinoma.

Posttransplant Lymphoproliferative Disorder in Children: A 360-degree Perspective

An earlier incorrect version of this article appeared online. This article was corrected on December 17, 2019.

Dural masses: meningiomas and their mimics

Meningiomas are the most common dural tumour. They are regularly being seen as an incidental finding on brain imaging and treated conservatively. However, there are many other dural masses which mimic their appearances, including primary neoplastic processes, metastases, granulomatous diseases and infection. While some of these are rare, others such as metastases and tuberculosis arise relatively frequently in practice. Although not pathognomonic, key features which increase the probability of a lesion being a meningioma include intralesional calcifications, skull hyperostosis, local dural enhancement and increased perfusion. It is important to have an awareness of these entities as well as their main imaging findings, as they have a wide range of prognoses and differing management strategies. This review outlines several of the most important mimics along with their imaging findings on both standard and advanced techniques with key features which may be used to help differentiate them from meningiomas.

MRI findings, including diffusion-weighted imaging and apparent diffusion coefficient value, in two cats with nasopharyngeal polyps and one cat with lymphoma

Objectives

Most nasopharyngeal masses in cats are lymphomas or polyps. To our knowledge, there is no report of MRI findings, including diffusion-weighted imaging (DWI) or apparent diffusion coefficient (ADC) values, of nasopharyngeal lymphomas and nasopharyngeal polyps in cats. This study aimed to evaluate the MRI findings of nasopharyngeal lymphomas and nasopharyngeal polyps, including DWI and ADC values.

Methods

MRI examination was performed on two cats with a histologically confirmed nasopharyngeal polyp and one cat with lymphoma. The magnetic resonance scanning protocol included T2-weighted imaging (T2WI), T1-weighted imaging (T1WI) and DWI. An ADC map was created based on DWI. ADC values were then calculated.

Results

MRI of the nasopharyngeal polyps revealed well-defined masses with strong rim enhancement, mass-associated stalk-like structures and asymmetric tympanic bulla lesions. The polyps appeared hyperintense on T2WI, hypo- to isointense on T1WI, and of mixed intensity or hypointense on DWI. On the ADC map, the masses appeared hyperintense. The ADC values of the polyps were 2.07 × 10^-3 mm²/s and 2.28 × 10^-3 mm²/s. MRI examination of the nasopharyngeal lymphoma revealed a strongly enhancing heterogeneous lesion. The mass appeared mildly hyperintense on T2WI, isointense on T1WI and hyperintense on DWI. On the ADC map, the mass appeared hypointense. The ADC value of the mass was 0.46 ×10^-3 mm²/s. The ADC values of the nasopharyngeal polyps were higher than the ADC value of the nasopharyngeal lymphoma.

Conclusions and relevance

Measurement of ADC values may be useful for differentiating between nasopharyngeal polyps and nasopharyngeal lymphomas.

Neuroradiological features of lymphomatosis cerebri: A systematic review of the English literature with a new case report

Lymphomatosis cerebri is a rare form of diffusely infiltrating primary central nervous system (CNS) lymphoma (PCNSL). The neuroradiological findings of lymphomatosis cerebri have not been adequately characterized, as the relevant literature consists only of case reports and small case series. The present study describes an unusual presentation of lymphomatosis cerebri in a 56-year-old immunocompetent woman who presented with diffusely infiltrating lesions with perivascular curvilinear enhancement on initial magnetic resonance imaging (MRI) and multiple nodules on the later follow-up computed tomography (CT) scan. A systematic review of the literature is also performed searching PubMed between January 1996 and December 2016 to collect all pertinent case reports and series written in the English language with pathologically confirmed lymphomatosis cerebri and diffuse infiltrative PCNSL without cohesive masses on initial MRI. A total of 45 cases were identified from 39 articles and the present case report. The patient ages ranged from 28 to 85 years (mean, 57.3 years). Only 3 patients (6.7%) were immunosuppressed (acquired immune deficiency syndrome patients). The most common clinical presentation was cognitive changes or dementia (46.7%). Cerebrospinal fluid analysis in all cases was non-specific. Diffuse and asymmetric abnormal T2-hyperintensity in deep and subcortical white matter was observed in all cases. Gray matter involvement (17.8%), spreading along the corticospinal tract (35.6%) and a slight mass effect (51.1%) also were observed. Contrast-enhanced patterns on MRI could be divided into three forms of non-enhancement (64.4%) and non-mass-like enhancement (35.6%) on initial MRI, as well as nodular or mass-like enhancement on the later follow-up MRI (15.6%). There were non-specific findings on magnetic resonance spectroscopy for 4 patients, on positron emission tomography/CT for 12 patients and on single-photon emission CT for 1 patient. Diagnosis was established by brain biopsy in 35 cases (77.8%) and autopsy in 9 cases (20%), involving B-cell lymphoma in 40 cases (88.9%) and T-cell lymphoma in 4 cases (8.9%). In conclusion, lymphomatosis cerebri, namely diffuse PCNSL or diffuse lymphoma of the CNS, is characterized by rapidly progressive dementia in the elderly, diffusely infiltrated CNS white matter along the corticospinal tract, possible involvement of the gray matter, a slight mass effect and varied contrast-enhancement patterns on MRI. Non-enhancement or non-mass-like enhancement on MRI may be a special form of diffuse PCNL during disease development and progression.

Apparent diffusion coefficient value for a B-cell central nervous system lymphoma in a cat

Case summary

This report involves a 10-year-old male mixed-breed cat with a B-cell central nervous system (CNS) lymphoma. The cat presented with ataxia progressing to left hemiparesis. While haematological findings were normal, serum biochemistry showed a high creatine phosphokinase concentration. MRI revealed a homogeneously enhancing well-demarcated extra-axial lesion involving the region of the left lateral aperture with oedema in left flocculus and left medulla oblongata. On diffusion-weighted imaging, the lesion margins showed marked hyperintensity relative to the right cerebellar hemisphere. On an apparent diffusion coefficient map, the lesion appeared hypointense, with an apparent diffusion coefficient value of 0.57 ± 0.01 × 10⁻³ mm²/s. Cerebrospinal fluid (CSF) analysis and cytology, and genetic analysis of CSF lymphoblasts confirmed a diagnosis of B-cell lymphoma. The owner opted for palliative treatment with prednisolone (1 mg/kg q12h); however, the cat died of dyspnoea 10 days after presentation.

Relevance and novel information

CNS lymphomas, which are the second most common intracranial tumours in cats, are highly infiltrative lesions and radical surgical excision is not recommended. Therefore, accurate diagnosis is crucial. However, contrast-enhanced MRI cannot always differentiate these lesions from other conditions, including other CNS tumours and strokes. To the best of our knowledge, this is the first report to document the diffusion-weighted imaging features and apparent diffusion coefficient value for a feline CNS lymphoma. These findings are expected to improve the diagnostic accuracy of these lesions in cats.

Leakage correction improves prognosis prediction of dynamic susceptibility contrast perfusion MRI in primary central nervous system lymphoma

To evaluate whether the cerebral blood volume (CBV) measurement with leakage correction from dynamic susceptibility contrast perfusion weighted imaging can be useful in predicting prognosis for primary central nervous system lymphoma (PCNSL). 46 PCNSL patients were included and classified by radiation therapy (RT) stratification into RT (n = 30) and non-RT (n = 16) groups. The corresponding histogram parameters of normalized CBV (nCBV) maps with or without leakage correction were calculated on contrast-enhanced T1 weighted image (CE T1WI) or on fluid attenuated inversion recovery image. The 75^th percentile nCBV with leakage correction based on CE T1WI (T1 nCBVL_75%) had a significant difference between the short and long progression free survival (PFS) subgroups of the RT group and the non-RT group, respectively. Based on the survival analysis, patients in the RT group with high T1 nCBVL_75% had earlier progression than the others with a low T1 nCBVL_75%. However, patients in the non-RT group with a high T1 nCBVL_75% had slower progression than the others with a low T1 nCBVL_75%. Based on RT stratification, the CBV with leakage correction has potential as a noninvasive biomarker for the prognosis prediction of PCNSL to identify high risk patients and it has a different correlation with the PFS based on the presence of combined RT.

Lymphomatosis cerebri: a rare variant of primary central nervous system lymphoma and MR imaging features

BACKGROUND

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL), characterized by diffuse infiltration without the formation of a discrete mass. The diagnosis of LC is a challenge because the imaging findings are atypical for lymphoma. The purpose of present study is to investigate MRI characteristics and clinical features of LC and potentially facilitate an early and accurate diagnosis of this often-missed disease.

METHODS

Seven patients (average 44 years, 19-58 years) with LC proved basing on MRI and histology were retrospectively reviewed the clinical data and cerebral MR imaging findings.

RESULTS

The common presenting symptoms were cognitive decline, behavioral disturbance, gait disturbance. All patients had both deep and lobar lesion distribution, and two of them had infratentorial involvement. Lack of contrast enhancement and subtle patchy enhanced pattern were observed in two and three patients, respectively. The remaining two patients presented multiple patchy enhancement. Most of the lesions were slightly hyperintense to normal brain on DWI as well as hyperintense on ADC maps. Three patients presented a pattern of marked decrease of NAA/Cr, increase of Cho/Cr, and two of the three cases showed increased Lip/Cr and Lac/Cr on MRS.

CONCLUSIONS

We conclude that diffuse bilateral lesions especially in deep and lobar region including white and gray matter, without enhancement or with patchy enhancement, marked decrease of NAA/Cr and increase of Cho/Cr, and increased Lip/Cr and Lac/Cr are suggestive of LC. Prompt recognition of these imaging patterns may lead to early diagnosis of LC and brain biopsy with improved prognosis.

Primary dural diffuse large B cell lymphoma mimicking parafalcine meningioma

A 58-year-old immunocompetent woman presented with complaints of recent onset recurrent generalised tonic-clonic seizures and left hemiparesis. On MRI a dural-based heterogeneously enhancing mass was seen along the falx cerebri mimicking parafalcine meningioma, causing brain parenchymal compression and vasogenic oedema in the right frontal and parietal lobes. The tumour was completely excised and on subsequent investigation it was diagnosed as diffuse large B cell type primary dural lymphoma. Chemotherapy with CHOP (cyclophosphamide, hydroxyl doxorubicin, vincristine and prednisone) regimen was started; however, the patient later died from episodes of acute pulmonary thromboembolism, aspiration pneumonia and septic shock.

Magnetic Resonance Spectroscopy and its Clinical Applications: A Review

In vivo NMR spectroscopy is known as magnetic resonance spectroscopy (MRS). MRS has been applied as both a research and a clinical tool in order to detect visible or nonvisible abnormalities. The adaptability of MRS allows a technique that can probe a wide variety of metabolic uses across different tissues. Although MRS is mostly applied for brain tissue, it can be used for detection, localization, staging, tumour aggressiveness evaluation, and tumour response assessment of breast, prostate, hepatic, and other cancers. In this article, the medical applications of MRS in the brain, including tumours, neural and psychiatric disorder studies, breast, prostate, hepatic, gastrointestinal, and genitourinary investigations have been reviewed.

How to facilitate early diagnosis of CNS involvement in malignant lymphoma

INTRODUCTION

Making the diagnosis of secondary CNS involvement in lymphoma can be difficult due to unspecific signs and symptoms, limited accessibility of brain/myelon parenchyma and low sensitivity and/or specifity of imaging and cerebrospinal fluid (CSF) examination currently available. Areas covered: MRI of the total neuroaxis followed by CSF cytomorphology and flow cytometry are methods of choice when CNS lymphoma (CNSL) is suspected. To reduce the numerous pitfalls of these examinations several aspects should be considered. New CSF biomarkers might be of potential diagnostic value. Attempts to standardize response criteria are presented. Expert commentary: Diagnosing CNSL remains challenging. Until diagnostic methods combining high sensitivity with high specifity are routinely introduced, high level of awareness and optimal utilization of examinations currently available are needed to early diagnose this potentially devastating disease.