ARTICLE REVIEW (MISCELLANEOUS)

(A)

Authors of Article

Hugh D. Curtin, William L. Hirsch.

Article Title

Imaging of Acoustic Neuromas

Journal Name

Neurosurgery clinics of North America

1)   Bibliography

Curtin, H. D., & Hirsch, W. L. (2008). Imaging of Acoustic Neuromas, 19, 175–205. https://doi.org/10.1016/j.nec.2008.02.012

2)   Purpose of the Article

The purpose of the article was to outline the image appearances of several lesion/tumor/abnormality that might mimic the acoustic neuroma and also to evaluate the appearance of acoustic neuroma in both MRI and CT.

3)   Brief Description of Procedure and Findings/Results

This article illustrates the detail of image appearance of several abnormalities occurred at part of head. This is to differentiate between abnormalities with the acoustic neuroma that may have similar appearances. The image appearances were briefly explained in both MRI and CT. The result was contrast-enhanced MRI is the excellent imaging to provide the evidence that patient does not has acoustic neuroma. However, CT scan examination is still a reliable imaging to demonstrate bony part including petrous bone and labyrinth that might useful for pre-operative planning of lesion removal.

4)   Conclusions and Comments

Both contrast-enhanced MRI and CT can be useful to evaluate types of lesion that occurred in head part. However, it is depending on the site of extending tumor/lesion. Both MRI and CT have advantages and disadvantages to compare.  

5)   Opinion of the Article

For me, the article is quite complicated. It is hard to find the objective of the study hence it is difficult to focus. The discussion overall is not in systematic order. I have to read again and again until I can understand.

(B)

Author of Article

Samuel A. C. MacKeith,  Richard S. Kerr,  Chris A. Milford

Article Title

Trend in Acoustic Neuroma Management:
A 20-year Review of the Oxford School Base Clinic (OSBC)

Journal Name

Journal of Neurological Surgery Part B

1) Bibliography

Mackeith, S. A. C., Kerr, R. S., & Milford, C. A. (2013). Trends In Acoustic Neuroma Management : A 20-Year Review of the Oxford Skull Base Clinic. Journal of Neurological Surgery Part B, 74, 194–200. https://doi.org/http://dx.doi.org/ 10.1055/s-0033-1342919.

2) Purpose of the Article

The objective of this paper is to make a review on acoustic neuroma management in two subsequent of 10years based on the known practice by international of United Kingdom health institutions and OSBC.

3) Brief description of Procedure and Findings/Result

In the early introduction part of this paper the authors had mentioned that as the new modern era was taken place, the MRI technology has overtake the credibility of CT scans in detection of small tumor and cancer including the acoustic neuroma. Based on their perspective, due to the development of the MRI scan itself, that imaging modalities had being able to detect a small tumor which provide a precise tumor size. Therefore, the knowledge to study for natural growth and progression of the tumor had also being arises.

The review was made prospectively based on the acoustic neuroma cases that has been reported by the ministry of United Kingdom and OSBC, from 1990 until 2009. Since the estabishment of collaboration between Neurosurgical and Otolaryngological (ENT) service, the coinciding cases was increase for the subsequent 10years. The data between these two main was compared that that include many important points like referral sources, diagnosis and decision making.

The result shown at early years between 1990 and 2009, there were about 1308 attending patients which 86% are benign and 55% show a positive diagnose for acoustic neuroma. As shown in pie chart below, a comparison between the management of acoustic neuroma cases based on UK Practice and OSBC in 2001 is well seen. By using a chi-square test with confidence level below than 0.05, the p-value shown is below than 0.001 which is almost negligible.

The authors were concluded that the management of the acoustic neuroma has significantly changed through the years, since the radiosurgery treatment become more preferable for treating a small tumor as compare to traditional surgery.  They also perceived and agreed on the ability of MRI scan machine  allowed the identification of the small tumor early, thus the disease can be treated as early as possible

4) Conclusion and Comment

Indeed, there is no single treatment is the best for treating one types of disease. Since the patho-physiology for each patient is definitely different and non-alike, with a guide the case can be controlled and handled smoothly and able to reduce patient suffering. Nowadays, the alternative micro-surgical treatment has been well spread, therefore the possibility for the management for this disease will changed following the technology paradigm.

5) Opinion

Quite a simple and compact published paper, where the authors is collaboration between two different departments. The result is expected and this study can be continued with the other subsequent 10years and the trend will be also can be monitored thoroughly. 

(c)

Authors of Article

Jonathan R. Newton, Muhammad Shakeel, Sam Flatman, Craig Beattie, Bhasker Ram

Article Title

Magnetic resonance imaging screening in acoustic neuroma

Journal Name

American Journal of Otolaryngology–Head and Neck Medicine and Surgery

1)   Bibliography

Newton, J. R., Shakeel, M., Flatman, S., Beattie, C., Ram, B., & Orl-hns, F. (2010). Magnetic resonance imaging screening in acoustic neuroma ☆. American Journal of Otolaryngology--Head and Neck Medicine and Surgery, 31(4), 217–220. https://doi.org/10.1016/j.amjoto.2009.02.005

2)   Purpose of the Article

Despite having high sensitivity to detect acoustic neuroma, It is known that MRI is expensive and high demand. Hence, this author wanted to study the efficiency and efficacy of magnetic resonance imaging screening in acoustic neuroma. This study aims to focus on 2 aspect which are to examine referral patterns of MRI screening for patients presenting with asymmetrical sensorineural hearing loss (ASHL) and to suggest appropriate screening criteria.

3)   Brief Description of Procedure and Findings/Results

This study looked at the efficacy of existing protocol which are popular Oxford and Charing Cross protocols by applying them at 132 patients with asymmetrical sensorineural hearing loss (ASHL) sent for MRI and to 30 patients who are positive acoustic neuroma. The authors did examine the case records and audiograms of patients who underwent MRI scans of the Internal Auditory Meatus at Aberdeen Royal Infirmary. Out of two hundred two case records were found, 132 MRI scans had been performed for unilateral sensorineural hearing loss. Trigeminal or facial nerve symptoms and hearing loss that are not the main symptom are the exclusion criteria. There were 70 cases excluded.

In addition, MRI scans, case records, and audiograms were reviewed for the last 30 patients diagnosed with ANs in the preeceding 6 years. Information from the audiograms was collected by a single researcher and was tabulated on Microsoft Excel. This information from the audiograms was analyzed in 3 different ways including popular Oxford and Charing Cross protocols. Lastly, the area between the ears was compared against the results from the MRI scans to determine whether the measurement was predictive of an MRI scan showing an AN. Audiogram results for all negative MRI scans and the 30 ANs were again analyzed. As a result, There were 2 (1.5%) ANs found of the 132 MRI scans performed for ASHL. Of the 132 scans performed, 98 (74%) fulfilled the Oxford protocol and 117 (89%) fulfilled the Charing Cross protocol. Of the scans performed for ASHL, 13 (10%) did not fit with any of the published criteria. Applying the Oxford screening protocol, 26 (87%) of ANs would have been diagnosed, with 4 (13%) being missed. Applying the Charing Cross screening protocol, 23 (77%) of ANs would have been identified, with 7 (23%) being missed. It was also found that neither protocol applied to 3 (10%) patients.

4)   Conclusions and Comments

The attempt of this study to create screening protocol of acoustic neuroma is not significant. Some difficulties exist in designing universally accepted screening protocol for patients suspected acoustic neuroma due to limiting factor which is cost for implementing contrast enhance MRI for early detection. 10% of tumors might be missed if protocol is applied base on audiologic criteria alone. Clinical suspicion with symptoms such as vertigo, tinnitus and cranial neuropathies are needed to support the decision making. Thus, there are other diagnostic tool and methods exist to detect the AN.

5)   Opinion of the Article

Honestly, this article did a very good job. The author tried to develop a standard protocol to be accepted universally in detecting acoustic neuroma. Somehow, it is not successful. Last but not least, the content of this article is well organized.

(D)

Authors of Article 

R Philip, N Prepageran, R Raman, L P H Jennifer, V Waran.

Article Title

Surgical Management of Large Acoustic Neuromas: A Review

Journal Name

Med J Malaysia

1) Bibliography

Philip, R., Orl-hns, M., Prepageran, N., Raman, R., Jennifer, L. P. H., & Waran, V. (2009). Surgical Management of Large Acoustic Neuromas : A Review, 64(4), 294–297.

2) Purpose of the Article

The aim of the study is to review acoustic neuroma surgical that were being done from 2001 to 2006. The purpose was to evaluate the performance and surgical outcome.

3) Brief Description of Procedure and Findings/Results

There are numerous options and factors to be considered in management of acoustic neuroma surgery. It depends on age of patient, size of tumor, preservation of hearing and the presence of co-morbid factors. This influence the decision of the management either microsurgical, stereotactic radiosurgery and conservative ‘wait and scan’. There are three common surgical approaches for acoustic neuromas; the middle cranial fossa, translabyrinthine and retrosigmoid. This article also mentioned that early detection of acoustic neuroma using combination of MRI scanning and other instrumentation were greatly help in reducing the mortality and morbidity.

4) Conclusions and Comments

Microsurgical management is the treatment of choice for these patients with the help of MRI imaging.

5) Opinion of the Article

This article was in order hence the whole content is easier to understand.

(E)

Authors of Article

Lennart Hardell, Michael Carlberg, Fredrik Soderqvist, and Kjell Hansson Mild

Article Title

Pooled analysis of case-control studies on acoustic neuroma diagnosed 1997-2003 and 2007-2009 and use of mobile and cordless phones

Journal Name

International Journal of Oncology

1) Bibliography

Hardell, L., Carlberg, M., Söderqvist, F., & Mild, K. H. (2013). Pooled analysis of case-control studies on acoustic neuroma diagnosed 1997-2003 and 2007-2009 and use of mobile and cordless phones. INTERNATIONAL JOURNAL OF ONCOLOGY, 43, 1036–1044. https://doi.org/10.3892/ijo.2013.2025

2) Purpose of the Article

The main objective of this article is to study the association between the uses of cordless phone in this era with increasing number of brain tumor including acoustic neuroma.

3) Brief description of Procedure and Findings/Result

Acoustic neuroma is a benign tumor where the disease is not persistent and can be treated. Means there will be no malignant transformation will occurs, however in a long periods this tumor might be able to cause of hearing impairment and tinnitus. The authors definitely sure that the calls made using the mobile phone or cordless phone produce relatively high radio-frequency electromagnetic field RF-EMF. Based on the study made by International Agency for Research on Cancer (IARC) on March 2011 reported a positive carcinogenic effect of high RF-EMF including glioma and acoustic neuroma.

A pooled analysis is used to find the association between the acoustic neuroma and the use of mobile phone and cordless phone in Sweden. The study were done between 1997-2003 and 2007-2009, where the subjects were randomly taken for both men and women throughout the country. The methods and analysis use for both subsequent years are similar with one-population based control which registered based on Swedish Population Registry. A phone interview via self-administered questionnaires were used to assess the exposure of the subjects. The structure questionnaires  consists of some demographic details such as occupations, types of exposure agents, habits of smoking, medical history, hereditary risk and also ionizing radiation exposure experience. However the prevalence of acoustic neuroma cases was reduced (n=73), therefore a pooled analysis was chosen for these two study periods. Exclusion and inclusion criteria analysis were well studied thus only 316 participation for case subjects and 3,530 for control. For both study, some responsible physicians were contacted to get the permission before each case was included. Therefore, medical records including the MRI and CT reports were also taken for tumor volume calculation. For 218 cases, all the tumor volume were calculated on the basis of the report done using MRI and CT scan shows no statistically difference between the aged cases or the latest one. However, the result still show an increasing of tumor size per year and per 100 h cumulative use of all types of phone.

Based on the discussion done, the odd ratio (OD) is increased by 100 h cumulative use and per year of latency mobile and cordless phone used. The result show a statistically significant association between the acoustic neuroma and analogue phone and digital 2G type of mobile phone. However there also limitation in collecting the data such as the observational bias and memorization or recall ability of the subject. The result is shown in Figure below.

4) Conclusion and Comment

In conclusion, risk for brain cancer arises since first use. For use of both mobile and cordless phones the risk was highest in the longest latency group. Tumor volume increased per 100 h of cumulative use and years of latency for wireless phones. Using the meningioma cases as reference entity gave similar results as with population based controls indicating that the results could not be explained by recall or observational bias. Thus, the study confirmed previous results of an association between use of mobile and cordless phones and acoustic neuroma.

5) Opinion

This paper had confused me in the abstract part, however it can be understandable when all the parts was read. Overall is nice but the authors keep repeating the same statement throughout the paper. The paper can be shorten using more simple words and explanation.

(F)

Author of Article

Nikdokht Farid

Article Title

Imaging of Vestibular Schwannoma and Other Cerebellopontine Angle Tumors

Journal Name

Operative Technique in Otolaryngology - Head and Neck Surgery

1) Bibliography 

Farid, N. (2014). Imaging of vestibular schwannoma and other cerebellopontine angle tumors. Operative Techniques in Otolaryngology - Head and Neck Surgery, 25(1), 87–95. https://doi.org/10.1016/j.otot.2013.11.011

2) Purpose of the article

This paper is a review made in discussion of imaging appearance of vestibular schwannoma and others cerebellopontine angles tumor for both usual and unusual imaging manifestation.

3) Brief description of Procedure and Findings/Result

Overall reading of this article, the authors had discussed the ability of CT scan in providing important details of temporal bone, osseous labyrinth but the MRI scans still become the best in evaluating CPA pathology due to high contrast enhancement in soft tissue. To be more specific when using T1-weighted post gadolinium enhancement with thin slices and T2-weighted 3D. 

This paper had interpret MRI images for several types of cerebellopontine angle tumor such as vestibular schwannomas,  meningioma, facial nerve schwannoma, meatastases, epidermoid cyst. 

Particularly for vestibular schwannoma, is about 85% prevalence and occurrence. The appearance of the lesions usualy iso-intense in T1 and hyper-intense on T2, however in appear a hypo-intense filling defect when using 3D heavily T2-weighted sequence. After using contrast, the VS usually show an intense enhancement whether homogeneous or non-homogeneous appearance. In the case of hearing loss, the lesions might be more prominent if using FLAIR sequence which shows a better elevation of intra-labyrinthine protein and accumulation or obstruction at cochlear aperture. Once, the diagnosis was made, the crucial key imaging features for the surgeon is the size, location and the distance between the lateral extent of the intra-canalicular portion of the tumor and IAC fundus. the reasons is to identify the prognosis that may affects the hearing lost and useful in modifying the surgical approach. However,it is important to note that identification of the facial nerve is not always possible for larger size of vestibular schwannomas.

 Unlike the vestibular shwannomas, the CPA meningioma is more valuable when using CT scan, which the calcification and hyperostosis as the common findings. As compare in MRI, the meningioma will appear like board based dural lesions that attached to petrous dura mater or inferior aspects of tentorium. Meanwhile, Classically, the facial nerve schwannoma has been describe as tubular-enhancement on MRI with a smooth enlagement of the facial nerve canal on CT. for congenital epidermoid cyst (CEC) will appears as hypoattenuaation on CT and mimicking fluid-filled cyst on MRI which is commonly hypo-intense in T1 and hyper-intense in T2.

4) Conclusion and comments

As a conclusion, this review by means is an exhausting review for CPA tumor found, but the focus to emphasis the common location of cerebellopontine angle tumor especially for vestibular schwannoma is very comprehensive and complete. 

5) Opinion of this article

Based on my reading, this article is far more complex with full study of the type of tumor in cerebellopontine angle and discussed briefly in the appearance of each tumor in CT and MRI imaging.