UpToDate: Dynamic Cervical Magnetic Resonance Imaging

Dynamic Cervical Magnetic Resonance Imaging

Dynamic MRI is useful to determine more accurately the number of levels where the spinal cord is compromised, and to better evaluate narrowing of the canal and intramedullary high-intensity signal (IHIS) changes. New information provided by flexion-extension MRI might change our strategy for CSM management 1).

Imaging of the cervical spine in functional positions has so far been limited to conventional Cervical spine x ray examinations or the scarcely available open magnetic resonance imaging (MRI). An MRI compatible positioning device allows MRI examinations in various positions and even in motion. In combination with high-resolution T2-weighted MRI it allows detailed functional imaging of the cervical spine and nerve roots.

The combination of a mechanical positioning device and a high-resolution 3D T2-weighted sequence (SPACE) on a conventional 1.5 T MRI allows kinematic imaging of the cervical spine as well as high-resolution imaging in the end positions, even in the presence of metal implants. In this proof of concept study a good visualization of narrowing of the spinal canal in functional positions could be achieved, showing the potential of MRI in functional positions for clinical and research applications 2).

The Dynamic Cervical Magnetic Resonance Imaging demonstrated a major number of findings and spinal cord compressions compared to the static exam. The dynamic exam is able to provide useful information in these patients, but Nigro et al., suggested a careful evaluation of the findings in the extension exam since they are probably over-expressed 3).

It is useful in correlating symptoms with the dynamic changes only noted on dMRI, and has reduced the incidence of misdiagnosis of myelopathy4).

In a study of Pratali et al., Dynamic cervical MRI was obtained using a standard protocol with the neck in neutral, flexion, and extension positions. The morphometric parameters considered were anterior length of the spinal cord (ALSC), posterior length of the spinal cord (PLSC), spinal canal diameter (SCD) and spinal cord width (SCW). Two observers analyzed the parameters independently, and the inter- and intra-observer reliabilities were assessed by the intraclass correlation coefficient (ICC).

18 patients were included in the study and all completed the dynamic MRI acquisition protocol. The inter- and intra-observer reliabilities demonstrated “almost perfect agreement” (ICC > 0.9, p < 0.001) for ALSC and PLSC in all positions. The SCD had inter- and intra-observer reliability classified as “almost perfect agreement” (ICC: 0.83-0.98, p < 0.001 and ICC: 0.90-0.99, p < 0.001, respectively) in all positions. The SCW had inter- and intra-observer reliability classified as “substantial agreement” (ICC: 0.73-0.94, p < 0.001 and ICC: 0.79-0.96, p < 0.001, respectively) in all positions. ALSC and PLSC in neutral, flexion and extension positions from the present study were significantly greater compared to the measurements previously published (P < 0.001).

The dynamic MRI protocol presented was safe and may allow a more complete evaluation of variations in the cervical spine in patients with CSM than traditional MRI protocols. The morphometric parameters based on this protocol demonstrated excellent inter- and intra-observer reliabilities 5).

References

1)

Zhang L, Zeitoun D, Rangel A, Lazennec JY, Catonné Y, Pascal-Moussellard H. Preoperative evaluation of the cervical spondylotic myelopathy with flexion-extension magnetic resonance imaging: about a prospective study of fifty patients. Spine (Phila Pa 1976). 2011 Aug 1;36(17):E1134-9. doi: 10.1097/BRS.0b013e3181f822c7. PubMed PMID: 21785299.

2)

Gerigk L, Bostel T, Hegewald A, Thomé C, Scharf J, Groden C, Neumaier-Probst E. Dynamic magnetic resonance imaging of the cervical spine with high-resolution 3-dimensional T2-imaging. Clin Neuroradiol. 2012 Mar;22(1):93-9. doi: 10.1007/s00062-011-0121-2. Epub 2011 Dec 23. PubMed PMID: 22193978.

3)

Nigro L, Donnarumma P, Tarantino R, Rullo M, Santoro A, Delfini R. Static and dynamic cervical MRI: two useful exams in cervical myelopathy. J Spine Surg. 2017 Jun;3(2):212-216. doi: 10.21037/jss.2017.06.01. PubMed PMID: 28744502; PubMed Central PMCID: PMC5506301.

4)

Kolcun JP, Chieng LO, Madhavan K, Wang MY. The Role of Dynamic Magnetic Resonance Imaging in Cervical Spondylotic Myelopathy. Asian Spine J. 2017 Dec;11(6):1008-1015. doi: 10.4184/asj.2017.11.6.1008. Epub 2017 Dec 7. Review. PubMed PMID: 29279758; PubMed Central PMCID: PMC5738303.

5)

Pratali RR, Smith JS, Ancheschi BC, Maranho DAC, Savarese A, Nogueira-Barbosa MH, Herrero CFPS. A Technique for Dynamic Cervical Magnetic Resonance Imaging Applied to Cervical Spondylotic Myelopathy: A Reliability Study. Spine (Phila Pa 1976). 2018 Jun 26. doi: 10.1097/BRS.0000000000002765. [Epub ahead of print] PubMed PMID: 29952883.

UpToDate: Retrograde VentriculoSinus Shunt

Retrograde VentriculoSinus Shunt

A retrograde ventriculosinus (RVS) shunt is a watertight connection that delivers excess cerebrospinal fluid(CSF) to the superior sagittal sinus (SSS) against the direction of blood flow. This method of CSF shunting utilizes the impact pressure (IP) of the bloodstream in the SSS to maintain the intraventricular pressure (IVP) more than the sinus pressure (SP) regardless of changes in posture or intrathoracic pressure (ITP) and discourages stagnation and clotting of blood at the venous end of the connection. It also utilizes collapse of the internal jugular vein (IJV) in the erect posture to prevent siphonage.

Since the 1950‘s, hydrocephalus can be treated with cerebrospinal fluid shunts, usually to the peritoneal cavityor to the right cardiac hearth atrium. However, due to their siphon effect, these shunts lead to non-physiological cerebrospinal fluid drainage, with possible co-morbidity and high revision rates. More sophisticated shunt valvesystems significantly increase costs and technical complexity and remain unsuccessful in a subgroup of patients. In an attempt to obtain physiological cerebrospinal fluid shunting, many neurosurgical pioneers shunted towards the dural sinuses, taking advantage of the physiological antisiphoning effect of the internal jugular veins. Despite several promising reports, the ventriculosinus shunts did not yet become standard neurosurgical practice.


50 RVS shunts were successfully implanted using valveless shunting catheters. There were no problems related to incorrect CSF drainage or sinus thrombosis. The results indicated arrest of the hydrocephalic process, normalization of the IVP and proper shunt function 1).

In 2016 Oliveira et al., published 3 consecutive cases who had previously undergone VPS revision and in which peritoneal space was full of adhesions and fibrosis. RVSS was performed as described by Shafei et al., with some modifications to each case. All 3 patients kept the same clinical profile after RVSS, with no perioperative or postoperative complications. However, revision surgery was performed in the first operative day in 1 out of 3 patients, in which the catheter was not positioned in the superior sagittal sinus. They propose that in cases where VPS is not feasible, RVSS may be a safe and applicable second option. Nevertheless, the long-term follow-up of patients and further learning curve must bring stronger evidence 2).


Baert et al., from the Department of Neurosurgery of Ghent University Hospital, Belgium implanted the retrograde ventriculosinus shunt, as advocated by El-Shafei, in 10 patients. They reports on the operation technique and long-term outcome, including 4 patients in whom this shunt was implanted as a rescue.

Implantation of a ventriculosinus shunt proved to be a feasible technique, warranting physiological drainage of cerebrospinal fluid. However, only in 3 out of 14 patients, functionality of the retrograde ventriculosinus shunt was maintained during more than 6 years follow-up. In there opinion, these shunts fail because present venous access devices are difficult to implant correctly and get too easily obstructed. After discussing possible causes of this frequent obstruction, a new dural venous sinus access device is presented.

An easy to implant and thrombogenic-resistant dural venous sinus access device needs to be developed before ventriculosinus shunting can become general practice 3).

1)

El-Shafei IL, El-Shafei HI. The retrograde ventriculosinus shunt: concept and technique for treatment of hydrocephalus by shunting the cerebrospinal fluid to the superior sagittal sinus against the direction of blood flow. Preliminary report. Childs Nerv Syst. 2001 Aug;17(8):457-65; discussion 466. PubMed PMID: 11508534.
2)

Oliveira MF, Teixeira MJ, Reis RC, Petitto CE, Gomes Pinto FC. Failed Ventriculoperitoneal Shunt: Is Retrograde Ventriculosinus Shunt a Reliable Option? World Neurosurg. 2016 Aug;92:445-453. doi: 10.1016/j.wneu.2016.05.038. Epub 2016 May 27. PubMed PMID: 27237416.
3)

Baert E, Dewaele F, Vandersteene J, Hallaert G, Okito Kalala JP, Roost DV. Treating Hydrocephalus with Retrograde VentriculoSinus Shunt Prospective Clinical Study. World Neurosurg. 2018 Jun 25. pii: S1878-8750(18)31313-5. doi: 10.1016/j.wneu.2018.06.097. [Epub ahead of print] PubMed PMID: 29953953.

UpToDate: Giant Prolactinoma

Giant prolactinoma

Their definition should be restricted to pituitary adenomas with a diameter of 40 mm or more, significant extrasellar extension, very high prolactin concentrations (usually above 1000 µg/L), and no concomitant GH or ACTH secretion.

Epidemiology

They represent only 2-3 % of all prolactinomas.

Giant prolactinoma are rare tumours. They are much more frequent in young to middle-aged men than in women with a male to female ratio of about 9:1. 1) 2).

Symptoms

Endocrine symptoms are often present but overlooked for a long period of time and diagnosis is eventually made when neurological complications arise from massive extension into the surrounding structures, leading to cranial nerve palsy, hydrocephalus, temporal lobe epilepsy or exophthalmos.

Prolactin concentrations are usually in the range of 1,000 to 100,000 µg/L, but may be underestimated by the so-called ‘high dose hook effect’.

Males

Sexual dysfunction is a hallmark of prolactinomas in males. Tumors that co-secrete prolactin and LH are extremely rare and and only a case reported in an adult male. In this case, normal testosterone was maintained by intact LH levels even in the face of the highest prolactin level reported to date 3).

Treatment

As in every prolactinoma, dopamine agonists are the first-line treatment allowing rapid alleviation of neurologic symptoms in the majority of the cases, a significant reduction of tumour size in three-fourths; of the patients and PRL normalization in 60-70%. These extensive tumours are usually not completely resectable and neurosurgery has significant morbidity and mortality. It should therefore be restricted to acute complications such as apoplexy or leakage of cerebrospinal fluid (often induced by medical treatment), or to patients with insufficient tumoral response or progression. Irradiation and temozolomide are useful adjuvant therapies in a subset of patients with aggressive/invasive tumours which are not controlled despite combined medical and surgical treatments. Because of these various challenges, it needs a multidisciplinary management in expert centres 4).

Case series

In 42 cases, male patients accounted for 71.4% of this series and were relatively younger (35.70±2.42 vs. 52.00±3.55 years, p=0.0011) and harbored bigger tumors (14.57 vs. 7.74 cm3, p=0.0179) compared to females. Almost all of these tumors showed suprasellar extension (97.6%) and cavernous sinus invasion (92.9%). Dopamine agonist represented an efficient method to control PRL concentrations (98.8%) and reduce tumor burdens (81.2 %). PRL normalization was detected in 13 out of the 27 patients initially treated with bromocriptine (BRC) whereas none of the 14 patients with first-line operation gained a normalization of PRL concentration after surgery. Although there was no reliable predictor of tumor response, First PRL reduction was a predictive criterion for the nadir PRL level during the long-time period of follow-up for first-line bromocriptine treatment. In conclusion, patients with giant prolactinomas did not gain more benefits from initial surgery. Dopamine agonist (BRC) should be first-line treatment for giant prolactinomas whereas operation merely served as a remedy for acute compression symptoms and dopamine agonist resistance. Consecutive monitoring of serum PRL levels in the early stage of initial BRC treatment is useful for evaluation of therapeutic effect and further therapeutic decision 5).


16 patients (43.7 % women); mean age at diagnosis: 42.1 ± 21 years. The most frequent presentation was compressive symptoms. The delay in diagnosis was higher in women (median of 150 months vs. 12 in men; p = 0.09). The mean maximum tumor diameter at diagnosis was 56.9 ± 15.5 mm, and mean prolactin levels were 10,995.9 ± 12,157.8 ng/mL. Dopamine agonists were the first-line treatment in 11 patients (mean maximum dose: 3.9 ± 3.2 mg/week). Surgery was the initial treatment in five patients and the second-line treatment in six. Radiotherapy was used in four cases. All patients but one, are still with dopamine agonists. After a mean follow-up of 9 years, prolactin normalized in 7/16 patients (43.7 %) and 13 patients (81 %) reached prolactin levels lower than twice the upper limit of normal. Mean prolactin level at last visit: 79.5 ± 143 ng/mL. Tumor volume was decreased by 93.8 ± 11.3 %, and final maximum tumor diameter was 18.4 ± 18.8 mm. Three patients are actually tumor free. Giant prolactinomas are characterized by a large tumor volume and extreme prolactin hypersecretion. Multimodal treatment is frequently required to obtain biochemical and tumor control 6).

References

1)

Shrivastava RK, Arginteanu MS, King WA, Post KD. Giant prolactinomas:clinical management and long-term follow up. J Neurosurg. 2002;97:299–306. doi: 10.3171/jns.2002.97.2.0299.
2)

Corsello SM, Ubertini G, Altomare M, Lovicu RM, Migneco MG, Rota CA, Colosimo C. Giant prolactinomas in men: efficacy of cabergoline treatment. Clin Endocrinol. 2003;58:662–670. doi: 10.1046/j.1365-2265.2003.01770.x.
3)

Tamagno G, Daly AF, Deprez M, Vroonen L, Andris C, Martin D, Beckers A. Absence of hypogonadism in a male patient with a giant prolactinoma: a clinical paradox. Ann Endocrinol (Paris). 2008 Feb;69(1):47-52. Epub 2007 Dec 20. PubMed PMID: 18082643.
4)

Maiter D, Delgrange E. The challenges in managing giant prolactinomas. Eur J Endocrinol. 2014 Feb 17. [Epub ahead of print] PubMed PMID: 24536090.
5)

Lv L, Hu Y, Yin S, Zhou P, Yang Y, Ma W, Zhang S, Wang X, Jiang S. Giant Prolactinomas: Outcomes of Multimodal Treatments for 42 Cases with Long-Term Follow-Up. Exp Clin Endocrinol Diabetes. 2018 Jun 25. doi: 10.1055/a-0597-8877. [Epub ahead of print] PubMed PMID: 29940665.
6)

Andujar-Plata P, Villar-Taibo R, Ballesteros-Pomar MD, Vidal-Casariego A, Pérez-Corral B, Cabezas-Agrícola JM, Álvarez-Vázquez P, Serramito R, Bernabeu I. Long-term outcome of multimodal therapy for giant prolactinomas. Endocrine. 2016 Oct 4. PubMed PMID: 27704480.
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