Early detection of meningeal localization in acute promyelocytic leukaemia patients with high presenting leucocyte count

Assessment of Arsenic Trioxide and All-trans Retinoic Acid for the Treatment of Pediatric Acute Promyelocytic Leukemia: A Report From the Children's Oncology Group AAML1331 Trial

Importance

All-trans retinoic acid (ATRA) and arsenic trioxide therapy without the use of maintenance therapy has been found to be beneficial for the treatment of adults with standard-risk acute promyelocytic leukemia (APL). However, it is unclear whether similar regimens are safe and beneficial for the treatment of high-risk APL or pediatric patients with standard-risk APL.

Objective

To assess whether treatment with an ATRA and arsenic trioxide-based regimen is safe and allows for the elimination or substantial reduction of chemotherapy use among pediatric patients with standard-risk or high-risk APL, respectively.

Design, Setting, and Participants

The Children's Oncology Group AAML1331 study is a nonrandomized, noninferiority trial that examined survival outcomes among 154 pediatric patients with APL compared with a historical control group of patients with APL from the AAML0631 study. Patients aged 1 to 21 years were enrolled at 85 pediatric oncology centers (members of the Children's Oncology Group) in Australia, Canada, and the US from June 29, 2015, to May 7, 2019, with follow-up until October 31, 2020. All patients had newly diagnosed APL and were stratified into standard-risk APL (white blood cell count <10 000/μL) and high-risk APL (white blood cell count ≥10 000/μL) cohorts.

Interventions

All patients received ATRA and arsenic trioxide continuously during induction therapy and intermittently during 4 consolidation cycles. Patients with high-risk APL received 4 doses of idarubicin during induction therapy only. The duration of therapy was approximately 9 months, and no maintenance therapy was administered.

Main Outcomes and Measures

Event-free survival (EFS) at 2 years after diagnosis.

Results

Among 154 patients (median age, 14.4 years [range, 1.1-21.7 years]; 81 male participants [52.6%]) included in the analysis, 98 patients (63.6%) had standard-risk APL, and 56 patients (36.4%) had high-risk APL. The median follow-up duration was 24.7 months (range, 0-49.5 months) for patients with standard-risk APL and 22.8 months (range, 0-47.7 months) for patients with high-risk APL. Patients with standard-risk APL had a 2-year EFS rate of 98.0% and an overall survival rate of 99.0%; adverse events included 1 early death during induction therapy and 1 relapse. Patients with high-risk APL had a 2-year EFS rate of 96.4% and an overall survival rate of 100%; adverse events included 2 relapses and 0 deaths. These outcomes met predefined noninferiority criteria (noninferiority margin of 10% among those with standard-risk APL and 14.5% among those with high-risk APL).

Conclusions and Relevance

In this nonrandomized, noninferiority trial, pediatric patients with standard-risk APL who received treatment with a chemotherapy-free ATRA and arsenic trioxide regimen experienced positive outcomes. Patients with high-risk APL also had positive outcomes when treated with a novel ATRA and arsenic trioxide-based regimen that included 4 doses of idarubicin during induction therapy only and no maintenance therapy. The 2-year EFS estimates were noninferior to the historical comparator group, and advantages of the regimen included shorter treatment duration, lower exposure to anthracycline and intrathecal chemotherapy, and fewer days hospitalized.

Trial Registration

ClinicalTrials.gov Identifier: NCT02339740.

A case of acute promyelocytic leukemia variant with derivative chromosome 3 der(3)t(3;8) associated with 8q partial gain

Background

Acute promyelocytic leukemia (APL) is characterized by fusion of PML/RARα genes as a result of t(15;17)(q24;q21). APL is now one of the curable hematological malignancies thanks to molecularly targeted therapies based on all-trans retinoic acid (ATRA) and arsenic trioxide (ATX). Extramedullary (EM) relapse is a rare event in APL, ear involvement being even more infrequent, with only six cases so far described. About 30–35% of patients with newly diagnosed APL have additional cytogenetics abnormalities, whose prognostic significance is still controversial. The most common additional aberration is trisomy 8 or partial gain 8q.

Case presentation

We describe here a novel unbalanced translocation der(3)t(3;8)(q29;q23.3-q24.3) associated with 8q partial gain in a 41 year-old man affected by APL in molecular remission after first line treatment, who had a responsive EM relapse in the auditory canal.

Conclusions

EM relapse is a rare event in APL and ear involvement is even more infrequent. To our knowledge, this is the first reported case of APL with a new der(3)t(3;8)(q29;q23.3-q24.3) and 8q partial gain associated with t(15;17)(q24;q21). Despite the recurrence of the disease at EM level, the clinical outcome of this patients was favorable.

Central nervous system involvement of acute promyelocytic leukemia, three case reports

Central nervous system (CNS) involvement of acute promyelocytic leukemia (APL) causes poor prognosis. Our three cases show that CNS can be involved at the first hematological recurrence, but predicting this is difficult. Triple intrathecal treatment and craniospinal irradiation were effective, while arsenic oxide failed to prevent and improve CNS involvement.

Current first- and second-line treatment options in acute promyelocytic leukemia

Outcome of acute promyelocytic leukemia (APL) has remarkably improved during the last 30 years, especially after the identification of PML-RARA oncogene as a key in the pathogenesis of APL and all-trans retinoic acid as therapeutic agent. Arsenic trioxide has been recently demonstrated to be the most effective single antileukemic agent and it has also showed synergistic action when combined with all-trans retinoic acid, decreasing relapse rate especially in low/intermediate-risk settings. Therapeutic advances led to complete remission rates of more than 90%, modifying disease history. In relapse setting, arsenic trioxide-based regimens showed efficacy for the achievement of second molecular complete remission. The most challenging issue in APL management remains the significant early deaths rate, nowadays the principal reason for treatment failure.

A case of central nervous system relapse in acute promyelocytic leukemia

A 70-year-old woman who have achieved complete remission (CR) of acute promyelocytic leukemia (APL) with all-trans retinoic acid and chemotherapy presented with abnormal sensation in the right lateral thigh and the bilateral legs. In addition, neurological examination revealed weakness of the left shoulder abduction, the right hand, and the bilateral lower limbs. Atypical promyelocytes were detected in the cerebrospinal fluid, in spite of normal finding in the peripheral blood smear. Magnetic resonance imaging showed gadolinium-enhanced multiple intradural/extramedullary lesions in the whole spine. Nerve conduction studies of the right limbs revealed sensorimotor conduction abnormalities, conspicuously in the posterior tibial and sural nerves. As a result, she was diagnosed as having intrathecal relapse of APL, associated with multiple mononeuropathy. The neurological symptoms were completely disappeared by intrathecal chemotherapy and whole-spine radiotherapy, suggesting that the neuropathy was possibly caused by meningeal infiltration affecting multiple spinal nerve roots. Since extramedullary or intrathecal relapse is extremely rare in APL compared with other types of leukemia, precise neurological evaluations and suitable treatment should be performed immediately, when APL patients with CR manifest some neurological symptoms.

Contemporary treatment of APL

Acute promyelocytic leukemia (APL) is characterized by coagulopathy, leukopenic presentation and sensitivity to anthracyclines, all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). For the last 25 years, APL has been treated with a combination of ATRA and chemotherapy for induction followed by consolidation and maintenance therapy. This general treatment approach has resulted in cure rates of 80-90 %. ATO, originally approved in relapsed APL, has been incorporated into contemporary upfront treatment regimens with excellent response rates. Recent studies show that most patients with APL can be cured with ATRA and ATO alone, eliminating cytotoxic chemotherapy and resulting in superior outcomes compared to standard treatment. We will herein review historical treatment of APL, treatment considerations in specific patient populations, and therapeutic updates.

Extramedullary disease in APL: a real phenomenon to contend with or not?

In the last 2 decades an increasing number of patients reported with extramedullary involvement among relapsed acute promyelocytic leukemia (APL) patients. Several investigators related this phenomenon to the relatively new treatment of all-trans-retinoic-acid (ATRA). In this review article we will examine what has been reported in the medical literature on extramedullary disease in APL: the common sites to be involved, the clinical risk factors to its development, the role of ATRA and arsenic tri-oxide and the recommended treatment.

Retinoic acid induces adhesion and migration in NB4 cells through Pyk2 signaling

Since the introduction of all-trans-retinoic acid (ATRA) treatment for acute promyelocytic leukemia (APL) there has been increasing concern about extramedullary disease (EMD) progression despite favorable response in the bone marrow. We postulated that ATRA treatment enhances migration and adhesion abilities possibly enabling APL cells to inhabit extramedullary sites. We revealed an increase in adhesion, migration and invasion capabilities of NB4 cells following ATRA treatment. ATRA induced upregulation of Pyk2 mRNA, protein and phosphorylation levels and enhanced Pyk2 interaction with paxillin and vinculin. Pyk2 inhibition resulted in a reduction of NB4 cell adhesion and migration following ATRA treatment. These results indicate that in vitro Pyk2 might function to regulate cell adhesion and motility following ATRA treatment and its upregulated expression may contribute to EMD development in APL patients.

Emerging new approaches for the treatment of acute promyelocytic leukemia

The introduction of all-trans retinoic acid (ATRA) in the late 1980s combined with anthracycline-based chemotherapy has revolutionized the prognosis of acute promyelocytic leukemia (APL) with more than 90% complete response rates and cure rates of approximately 80%. The subsequent advent of arsenic trioxide (ATO) in 1990s and progress in the treatment of APL have changed its course from a highly fatal to a highly curable disease. Despite the dramatic improvement in clinical outcome of APL, treatment failure still occurs due most often to early death. Relapse has become increasingly less frequent, most commonly occurring in patients with high-risk disease. A major focus of research for the past decade has been to develop risk-adapted and rationally targeted nonchemotherapy treatment strategies to reduce treatment-related morbidity and mortality to low- and intermediate-risk or older patients while targeting more intensive or alternative therapy to those patients at most risk of relapse. In this review, emerging new approaches to APL treatment with special emhasis on strategies to reduce early deaths, risk-adapted therapy during induction, consolidation and maintenance, as well as an overview of current and future clinical trials in APL will be discussed.

Extramedullary disease in acute promyelocytic leukemia: two-in-one disease

In acute promyelocytic leukemia (APL), extramedullary disease (EMD) is particularly rare and shows special clinical and biological features. It is estimated that about 3-5% of APL patients will suffer extramedullary relapse. The most common site of EMD in APL is the central nervous system (CNS). At present, there are still many issues of EMD in APL needing further clarification, including pathogenesis, risk factors, prognosis and treatment. A better understanding of the biological mechanisms underlying EMD is important to be able to devise more effective CNS prophylaxis and induction-consolidation therapeutic strategies.

Central nervous system relapse in CD56+, FLT3/ITD+ promyelocytic leukemia

Central nervous system (CNS) involvement in acute promyelocytic leukemia (APL) is rare and tends to be seen mostly following treatment with all-trans retinoic acid (ATRA), due to prolonged patient survival and poor penetration of the drug in the CNS. At least 10% of extramedullary relapses in APL involve the CNS, and associated factors include an increased age, the BCR isoform, the development of differentiation syndrome, a high white cell count at presentation and hemorrhage into the CNS during induction therapy. We present the case of a patient with high-risk APL, CD56+, CD2+ in whom a CNS relapse was diagnosed through the presence of a PML/RARα rearrangement on PCR of the cerebrospinal fluid (CSF).

Prospective study of a therapeutic regimen with all-trans retinoic acid and anthracyclines in combination of cytarabine in children with acute promyelocytic leukaemia: the Japanese childhood acute myeloid leukaemia cooperative study

In childhood acute promyelocytic leukaemia (APL), the efficacy of therapy combining cytarabine with all-trans retinoic acid (ATRA) and anthracyclines remains unclear in terms of long-term prognosis. Between August 1997 and March 2004, 58 children with APL (median age: 11 years) were enrolled into an acute myeloid leukaemia (AML) study (AML99-M3) and followed up for a median time of 86 months. The regimen included ATRA and anthracyclines combined with cytarabine in both induction and consolidation. In induction, two patients died of haemorrhage and four patients developed retinoic acid syndrome. Of 58 patients, 56 (96·6%) achieved complete remission, two of whom relapsed in the bone marrow after 15 and 19 months respectively. Sepsis was a major complication, with an incidence of 5·6-10·9% in the consolidation blocks, from which all but one of patients recovered. Consequently, 7-year overall and event-free survival rates were 93·1% and 91·4% respectively, and cumulative incidence of relapse plateaued at 3·6% after 2 years. Follow-up survey of 54 patients revealed no patients with late cardiotoxicity or secondary malignancy, except one with asymptomatic prolongation of QTc interval. This study suggests that the combination of cytarabine with ATRA and anthracycline-based therapy may have useful implications in the perspective of long-term prognosis and late adverse effects for childhood APL.

Central nervous system involvement at the time of presentation in acute promyelocytic leukemia

Central nervous system (CNS) involvement is rarely observed in acute promyelocytic leukemia (APML). Most cases of CNS involvement occur at relapse rather than at presentation. Because of the extremely low incidence of CNS disease, diagnostic lumbar puncture is not routinely required and prophylactic intrathecal chemotherapy is not routinely administered. Here, we describe a teenage patient with newly diagnosed APML, chloromas, and symptomatic CNS involvement confirmed by MRI and cerebrospinal fluid (CSF) findings.

How I treat acute promyelocytic leukemia

Acute promyelocytic leukemia is the first malignant disease highly curable with targeted therapy directed at a unique molecular abnormality. The characteristic bleeding diathesis is the most notorious manifestation of the disease, which historically has accounted for a high mortality rate during induction. Acute promyelocytic leukemia is one of the few hematologic diseases that must be recognized under the microscope by the practicing hematologist because early institution of all-trans retinoic acid (ATRA) at the first suspicion of the disease before confirmation of the diagnosis and aggressive blood product support are critical to reduce early mortality. ATRA plus anthracycline-based chemotherapy for induction and consolidation followed by maintenance ATRA with low-dose chemotherapy is currently the standard of care. However, the combination of ATRA and arsenic trioxide, with minimal chemotherapy to control leukocytosis, is very effective therapy for newly diagnosed patients. This combination may replace conventional approaches for most, if not all, patients in the very near future. Acute promyelocytic leukemia should be considered in any patient with newly diagnosed acute myeloid leukemia because the treatment is urgent and different from all other subtypes.

Central nervous system involvement at first relapse in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline monochemotherapy without intrathecal prophylaxis

BACKGROUND

The prevalence of and risk factors for central nervous system recurrence in patients with acute promyelocytic leukemia are not well established and remain a controversial matter.

DESIGN AND METHODS

Between 1996 and 2005, 739 patients with newly diagnosed acute promyelocytic leukemia enrolled in two consecutive trials (PETHEMA LPA96 and LPA99) received induction therapy with all-trans retinoic acid and idarubicin. Consolidation therapy comprised three courses of anthracycline monochemotherapy (LPA96), with all-trans retinoic acid and reinforced doses of idarubicin in patients with an intermediate or high risk of relapse (LPA99). Central nervous system prophylaxis was not given.

RESULTS

Central nervous system relapse was documented in 11 patients. The 5-year cumulative incidence of central nervous system relapse was 1.7% (LPA96 3.2% and LPA99 1.2%; p=0.09). The cumulative incidence was 0%, 0.8%, and 5.5% in low-, intermediate-, and high-risk patients, respectively. Relapse risk score (p=0.0001) and the occurrence of central nervous system hemorrhage during induction (5-year cumulative incidence 18.7%, p=0.006) were independent risk factors for central nervous system relapse.

CONCLUSIONS

This study shows a low incidence of central nervous system relapse in patients with acute promyelocytic leukemia following therapy with all-trans retinoic acid and anthracycline without specific central nervous system prophylaxis. Central nervous system relapse was significantly associated with high white blood cell counts and prior central nervous system hemorrhage, which emerged as independent prognostic factors.

Incidence of extramedullary disease in patients with acute promyelocytic leukemia: a single-institution experience

Using current treatment regimens, over 90% of patients with acute promyelocytic leukemia will achieve complete remission (CR). However, approximately 30% of these patients will relapse, including a small proportion who will develop extramedullary disease (EMD). In this study, we investigated the incidence of EMD in 263 patients with APL who were treated at our institution from January 1990 to May 2008. With a median follow-up of 31 months (range 2 days-203 months), 8 (3%) patients developed EMD. The most commonly affected site was the central nervous system (n = 7). Before developing EMD, one patient had achieved CR with a chemotherapy-only regimen, six patients had achieved CR with all-trans-retinoic acid (ATRA)-based regimens, and one patient had achieved CR with an ATRA plus arsenic trioxide (ATO)-based regimen. The EMD conferred a poor prognosis; five patients died within 4 months of developing EMD. The molecular status did not predict EMD; four patients had a negative PCR for the PML-RARA transcripts prior to relapse with EMD. In conclusion, the incidence of EMD is low. We were unable to identify any specific factors that could predict the development of EMD.

Isolated central nervous system relapse in childhood acute promyelocytic leukemia

Central nervous system (CNS) involvement is rare in acute promyelocytic leukemia (APL). The majority of CNS relapses occur in patients with hyperleukocytosis at presentation, and the optimal management of such patients is still controversial. We describe a 13-year-old boy with APL who developed an isolated CNS relapse after first-line treatment with all-trans retinoic acid and chemotherapy. A second remission was achieved with a regimen consisting of intrathecal chemotherapy, intravenous high-dose cytarabine, and oral 6-mercaptopurine. All-trans retinoic acid was avoided owing to severe complications during initial therapy. The patient remains in molecular remission at 9 months after autologous stem cell transplant. Prognostic factors of CNS relapse in children with APL are needed to define the indications for CNS prophylaxis in this group of patients.

Curative strategies in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) was initially described as a distinct clinical entity in 1957, one year before the first meeting of the American Society of Hematology. With routine administration of all-trans retinoic acid (ATRA) combined with chemotherapy in the early 1990s and arsenic trioxide (ATO) in the late 1990s, cure can now be expected in the majority of both newly diagnosed and relapsed patients. ATRA with anthracycline-based chemotherapy for induction and consolidation followed by ATRA plus low-dose chemotherapy maintenance is currently the standard of care for newly diagnosed patients. Early institution of ATRA before the diagnosis is confirmed by genetics and aggressive blood product support are important to reduce induction mortality, which remains approximately 10% among patients entered on clinical trials, but is certainly higher when all patients are considered. The relapse rate among high-risk patients is approximately 20%, and new strategies include administration of intensified anthracyclines, intermediate- or high-dose ara-C in either induction or consolidation, or ATO as early consolidation. Central nervous system (CNS) prophylaxis for such patients and those with relapsed disease may be important to prevent the development of extramedullary disease. New therapeutic strategies have focused on minimizing chemotherapy and administering ATRA plus ATO as initial therapy. Recent studies suggest that patients who are molecularly negative after intensive consolidation may not benefit from maintenance therapy. Most exciting is the combination of ATRA and ATO, given with minimal chemotherapy only for leukocytosis, which is a very effective new strategy for patients who are unable to tolerate anthracyclines or older adults and soon may replace conventional therapy for many patients. Patients with relapsed disease do well with ATO followed by autologous hematopoietic stem cell transplantation.

Treatment of relapsed or refractory acute promyelocytic leukemia

Current treatment for acute promyelocytic leukemia (APL) usually includes an induction phase with all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy, followed by a consolidation phase of anthracycline-based chemotherapy and maintenance therapy with ATRA with or without low-dose chemotherapy for 1-2 years. This treatment strategy results in a high complete remission (CR) rate of about 90% and an overall survival rate of 80%. About 5%-30% of patients relapse, mainly patients with high-risk APL. Relapse at extramedullary sites, which occurs in approximately 3%-5% of patients, is emerging as a new issue. Treatment of relapsed/advanced APL includes the use of arsenic trioxide (ATO), gemtuzumab ozogamicin, and hematopoietic stem cell transplantation. ATO is currently the most effective therapeutic agent in relapsed APL. Hematopoietic stem cell transplantation is becoming a common strategy after achieving remission with ATO. Autologous transplant appears to have a more favorable outcome than allogeneic transplant in this setting, particularly when carried out during second remission, primarily because of significantly higher treatment-related mortality with allogeneic transplants. Allogeneic transplant, however, should be strongly considered for patients who remain molecularly positive. Future directions for APL therapy should include developing agents that can prevent relapse, particularly for high-risk patients. Other future treatment strategies may include use of ATO administered concomitantly or sequentially with chemotherapy, gemtuzumab or FLT-3 inhibitors that may obviate the need for autologous transplantation, and posttransplant maintenance perhaps with FLT-3 inhibitors.

Extramedullary disease and targeted therapies for hematological malignancies—is the association real?

During the past years targeted therapies have gained a major role in the treatment of cancer patients, including those with hematological malignancies. Extramedullary involvement is a rare manifestation of acute and chronic leukemias and of multiple myeloma. Nevertheless, with the expanding use of targeted treatments there is an impression that the incidence of extramedullary relapses is increasing. We reviewed the reports on this phenomenon in patients treated with all-trans-retinoic acid and arsenic trioxide for acute promyelocytic leukemia, thalidomide and bortezomib for multiple myeloma and imatinib for chronic myeloid leukemia. The pathogenetic mechanisms suggested are: life prolongation by these treatments allowing for disease progression arising from dormant cells; poor penetration of the drugs to sanctuary sites like the central nervous system; the requirement of some of these drugs, especially thalidomide, for the marrow microenvironment to exert their action; and finally, a possible active role for some of the drugs, like all-trans-retinoic acid. Since the use of these targeted therapies is expanding we should be aware of this association.

Late relapses in acute promyelocytic leukaemia

From January 1988 to December 1997, among 53 acute promyelocytic leukaemia patients in 1st complete remission (CR) after 5 years from diagnosis, we observed 5 late relapses (9.4%) after 60, 61, 71, 101 and 155 months from diagnosis; 3 of those late relapses (7.7%) occurred among 39 patients previously treated with all-trans-retinoic acid. An involvement of the mastoid occurred in 3/5 patients (60%), compared with 2/32 patients (6.3%) at an early relapse (p < 0.02). As to the treatment of the late relapse, 1 patient received all-trans-retinoic acid alone followed by allogeneic transplantation and 4 patients were treated according to the GIMEMA 0191 protocol. All patients achieved a 2nd CR and are still alive: 4 in the 2nd molecular CR after 6, 33, 34 and 115 months; 1 relapsed after 15 months and is now in the 3rd CR. In conclusion, a late relapse occurred in a sizeable fraction of acute promyelocytic leukaemia patients: the high rate of ear involvement might be explained considering the ear as a 'disease sanctuary'.

Extramedullary relapse in acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy

We analyzed the incidence, presenting features, risk factors of extramedullary (EM) relapse occurring in acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) and chemotherapy by using a competing-risk method. In total, 740/ 806 (92%) patients included in three multicenter trials (APL91, APL93 trials and PETHEMA 96) achieved CR, of whom 169 (23%) relapsed, including 10 EM relapses. Nine relapses involved the central nervous system (CNS) and one the skin, of which two were isolated EM relapse. In patients with EM disease, median WBC count was 26950/mm3 (7700-162000). The 3-year cumulative incidence of EM disease at first relapse was 5.0%. Univariate analysis identified age <45 years (P=0.05), bcr3 PML-RARalpha isoform (P= 0.0003) and high WBC counts (> or = 10,000/ mm3) (P<0.0001) as risk factors for EM relapse. In multivariate analysis, only high WBC count remained significant (P= 0.001). Patients with EM relapse had a poorer outcome since median survival from EM relapse was 6.7 months as compared to 26.3 months for isolated BM relapse (P=0.04). In conclusion, EM relapse in APL occurs more frequently in patients with increased WBC counts (> or = 10,000/mm3) and carries a poor prognosis. Whether CNS prophylaxis should be systematically performed in patients with WBC > or = 10,000/mm3 at diagnosis remains to be established.

Leptomeningeal neoplasia: epidemiology, clinical presentation, CSF analysis and diagnostic imaging

The incidence of leptomeningeal metastasis over the past several decades has increased among solid tumor patients and decerased in patients with hematologic malignancies. Improvements in systemic therapies are likely responsible for both changes; solid tumor patients are living longer and, threfore, are at higher risk to develop leptomeningeal tumors while patients with hematologic malignancy have benefitted from more aggressive central nervous system prophylaxis. Regardless, both types of patients present with symptoms referrable to multiple levels of the central nervous system and a careful dignostic approach incorporating cerebrospinal fluid studies and appropriate neuroimaging is critical.