Fwd: Preoperative differentiation of benign from malignant thyroid nodules,Diffusion-weighted imaging (DWI) is highly accurate for discrimination between benign and malignant thyroid nodules.

Preoperative differentiation of benign from malignant thyroid nodules,Diffusion-weighted imaging (DWI) is highly accurate for discrimination between benign and malignant thyroid nodules.

To:

Differentiation between benign and malignant thyroid nodules using diffusion-weighted imaging, a 3-T MRI study p. 460
Leila Aghaghazvini, Hashem Sharifian, Nasrin Yazdani, Melina Hosseiny, Saina Kooraki, Pirouz Pirouzi, Afsoon Ghadiri, Madjid Shakiba, Soheil Kooraki
DOI:10.4103/ijri.IJRI_488_17  
Background: Preoperative differentiation of benign from malignant thyroid nodules remains a challenge. Aims: This study assessed the accuracy of diffusion-weighted imaging (DWI) for differentiation between benign and malignant thyroid nodules. Materials and Methods: Preoperative DWI was performed in patients with thyroid nodule by means of a 3-T scanner magnetic resonance imaging (MRI). Images were obtained at b value of 50, 500, and 1000 mm2/s to draw an ADC (apparent diffusion coefficient) map. Findings were compared with postoperative histopathologic results. Receiver operating characteristic curve was used to assess the accuracy of different cutoff points. Results: Forty-one thyroid nodules (26 benign and 15 malignant) were included in this study. None of static MRI parameters such as signal intensity, heterogeneity, and nodule border was useful to discriminate between benign and malignant lesions. Mean ADC value was (1.94 ± 0.54) × 10-3 mm2/s and (0.89 ± 0.29) × 10-3 mm2/s in benign and malignant nodules, respectively (P-value < 0.005). ADC value cutoff of 1 × 10-3 mm2/s yielded an accuracy, sensitivity, and specificity of 93%, 87%, and 96% to discriminate benign and malignant nodules. Conclusion: DWI is highly accurate for discrimination between benign and malignant thyroid nodules.
http://www.ijri.org/currentissue.asp?sabs=y

Fwd: Normal adrenal gland thickness on computerized tomography

Normal adrenal gland thickness on computerized tomography

To:

 in an Asian Indian adult population p. 465
Reetu John, Tharani Putta, Betty Simon, Anu Eapen, Felix Jebasingh, Nihal Thomas, Simon Rajaratnam
DOI:10.4103/ijri.IJRI_129_18  

Context: The size and morphology of the adrenal glands are affected by several physiological and pathological conditions. Radiologists need to be aware of the normal thickness of adrenal gland to accurately assess patients with suspected adrenal pathology. However, there is limited data on the normal size of the adrenal glands. Moreover, this has not been studied in our population. Aims: To study the normal thickness of adrenal gland on computerized tomography (CT) in Indian adult population. Settings and Design: Retrospective study in a tertiary care hospital in Southern India. Subjects and Methods: Our study included 586 adults who underwent a CT abdominal angiogram over 15 months, and excluding patients with clinical or imaging evidence of adrenal disease. The measurements made included: the maximum thickness of the body, medial and lateral limbs, measured perpendicular to the long axis. Results: The median age was 51 (range: 18–85) years. The mean maximum thickness of the adrenal body, medial, and lateral limbs were 7.2 ± 1.8, 4.1 ± 1.1, and 4.3 ± 1.1 mm on the right side and 8.8 ± 1.9, 4.7 ± 1.1, and 4.9 ± 1.3 mm on the left. The cumulative thickness of the body and the limbs were 15.6 ± 3.7 mm and 18.4 ± 3.8 mm on the right and left sides, respectively. There was a statistically significant difference in all the measurements between the right and left adrenal glands (all P values = 0.000) and between men and women, being larger in men (P value <0.05). Among our patients 27% had at least one adrenal gland body measuring ≥10 mm in thickness. Conclusions: Our study has defined the normal range of adrenal gland thickness in an Asian Indian adult population, which may be used as a baseline reference for future research and as a reference for radiological reporting.
http://www.ijri.org/currentissue.asp?sabs=y

Fwd: Metastases to the breast from extramammary malignancies

Metastases to the breast from extramammary malignancies
To:

 p. 470
Tanvi Vaidya, Subhash Ramani, Ashita Rastogi
DOI:10.4103/ijri.IJRI_218_18  
Metastases to the breast from extra-mammary malignancies are extremely uncommon. The discovery of a breast mass in a patient with a known primary tumor elsewhere poses a diagnostic challenge to the clinician. An awareness of the various malignancies that can metastasize to the breast and accurate diagnosis of the same is essential to avoid an unnecessary mastectomy and to guide further therapy. In this case series, we describe such clinical scenarios with an emphasis on the imaging features of metastases to the breast, which will enable radiologists to recognize this entity with greater ease.
http://www.ijri.org/currentissue.asp?sabs=y

Metastases to the breast from extra-mammary malignancies are extremely uncommon, with a prevalence ranging from 1.7% to 6.6%.^[1] The most common sources of metastases to the breast are lymphomas/leukemias and melanomas. Rare primary tumors to metastasize to the breast include carcinomas of the lung, ovary, and stomach, and even more uncommonly carcinoid tumors, hypernephromas, carcinomas of the liver, tonsil, pleura, pancreas, cervix, endometrium, and bladder. The dissemination occurs via both hematogenous and lymphatic routes.^[1],[2]

The discovery of a breast mass in a patient with a known primary tumor elsewhere or with a previous history of cancer at another site poses a diagnostic challenge to the clinician. An awareness of the various malignancies that can metastasize to the breast and accurate diagnosis of the same is essential in order to avoid an unnecessary mastectomy and to guide further therapy.

In this article, we present six cases of metastases to the breast, in patients with a primary extramammary malignancy. Metastases in these primary tumors are exceedingly rare, and hence, this case series would serve as a valuable addition to the existing literature. In addition, we present a review on the subject with an emphasis on imaging findings.

Case 1

A 40-year-old lady presented with menorrhagia for about 8 months. She underwent a contrast-enhanced CT scan of the abdomen and pelvis, which revealed a heterogeneously enhancing myometrial mass, with atypical imaging features [Figure 1]A. There was no evidence of distant metastases on cross-sectional imaging. The patient underwent a total hysterectomy with a bilateral salpingo-oophorectomy. Histopathological evaluation of the myometrial mass revealed an intermediate grade leiomyosarcoma (Immunohistochemistry IHC – Mib labeling index of 50%). Thereafter, she presented with a lump in the right breast, progressively increasing in size over a period of 6 months.

Figure 1 (A-D): (A) Coronal sections of contrast-enhanced CT pelvis images showing a heterogeneously enhancing mass involving the myometrium of the uterine fundus (red arrows). (C and D) Right mammogram (extended CC view (C) and MLO view (D)) showing a well-circumscribed isodense mass in the upper outer quadrant of the right breast (red asterisk). (B) Ultrasonography image showing a well-defined, round hypoechoic mass at the 10 o'clock position in the right breast Click here to view

Mammography revealed the presence of a well-circumscribed isodense mass in the upper outer quadrant of the right breast [Figure 1]C and [Figure 1]D. Breast ultrasonography demonstrated a well-defined solid, hypoechoic mass with mild posterior acoustic enhancement, at the site of palpable abnormality [Figure 1]B. A core biopsy of the lesion revealed a spindle cell tumor exhibiting focally moderate to marked nuclear atypia. On IHC, tumor cells were positive for smooth muscle actin, desmin, H-caldesmon and showed a high Mib-1 count. The histopathology report was conclusive for leiomyosarcoma in the clinical context. A contrast-enhanced CT abdomen scan was subsequently done which revealed a metastatic lesion in the liver and a retroperitoneal metastatic nodal mass. Thereafter, the patient received palliative chemotherapy for 2 years but did not survive.

Case 2

A 31-year-old lady, with poorly differentiated adenocarcinoma of the stomach (stage T3N2M0), underwent a radical gastrectomy. She was receiving adjuvant chemo-radiotherapy (CT-RT) during which she developed abdominal distention, along with diffuse pain in the left breast with redness of the overlying skin over a period of 1 month. A contrast-enhanced CT scan of the thorax and abdomen with a mammogram was performed. Contrast-enhanced CT of the thorax and abdomen revealed ill-defined enhancement in the left breast [Figure 2]A.

Figure 2 (A-C): (A) Axial sections of contrast-enhanced CT thorax images showing diffuse ill-defined enhancement in the left breast (red arrows). (B) Bilateral mammograms (CC view) showing a diffuse increase in density in the left breast (red arrows), with thickening of the overlying skin and the nipple–areola complex (red asterisks). (C) Ultrasonography image showing an ill-defined hypoechoic lesion replacing the fibro-glandular parenchyma of the left breast (red asterisk) Click here to view

Mammography revealed a diffuse increase in density involving the left breast, with thickening of the overlying skin and the nipple–areola complex [Figure 2]B. Breast ultrasonography demonstrated an ill-defined hypoechoic lesion replacing the fibro-glandular parenchyma [Figure 2]C. A left breast core biopsy revealed poorly differentiated carcinoma with signet ring cell morphology. Immunohistochemistry revealed positivity for CK 7, ER, CDX2, CK 20, and GCDFP, which was consistent with metastasis from carcinoma stomach. Contrast-enhanced CT abdomen revealed ascites with peritoneal metastases. The patient is being treated with palliative chemotherapy since then, with stable disease.

Case 3

A 37-year-old lady, with carcinoma cervix (stage IIIa) receiving concomitant chemoradiation and brachytherapy for the same, developed a lump in the left breast, gradually increasing over a period of 3 months. A mammogram and a screening ultrasonography of the abdomen were performed.

Mammography revealed a well-circumscribed, isodense mass in the upper central region of the left breast [Figure 3]A and [Figure 3]B. A breast ultrasound revealed a predominantly hypoechoic lesion in the upper central region showing mild internal vascularity [Figure 3]C. Fine-needle aspiration of the lesion revealed clusters of squamous epithelial cells, consistent with metastasis from cervical carcinoma. An ultrasound of the abdomen revealed evidence of liver metastases. The patient was put on palliative chemotherapy, is now being followed up annually.

Figure 3 (A-C): (A and B) Bilateral mammograms (MLO view (A) and CC view (B)) showing a well-circumscribed, isodense mass in the upper central region of the left breast (red arrows). (C) Ultrasonography image showing a well-defined hypoechoic lesion at the 12 o'clock position in the left breast (red asterisk) Click here to view

Case 4

A 16-year-old girl, with Ewing's sarcoma of the left ninth rib being treated with chemotherapy, presented with a slow growing lump in the left breast. About 3 months after commencement of therapy, a contrast-enhanced CT of the thorax was performed for monitoring disease response. The CT revealed a heterogeneously enhancing mass involving the left ninth rib causing bony destruction with intrathoracic extension. In addition, an irregular heterogeneously enhancing mass with central necrosis was also seen incidentally in the left breast. Bilateral pleural effusion was seen [Figure 4]A,[Figure 4]B,[Figure 4]C. A breast ultrasound revealed a predominantly hypoechoic mass with irregular margins in the upper central region [Figure 4]D. A fine-needle aspiration cytology study of the left breast mass revealed cytologic features of PNET (Primitive neuro-ectodermal tumor)/Ewing's sarcoma with positivity for CD99, consistent with metastases from the primary. The patient was treated with systemic chemotherapy and received radiotherapy to the breast. This regimen yielded a good response to therapy with a decrease in disease burden.

Figure 4 (A-D): (A) Axial contrast-enhanced CT image of the thorax showing a heterogeneously enhancing mass with irregular margins in the left breast (yellow arrow). Incidentally seen is bilateral pleural effusion. (B) Sagittal contrast-enhanced CT image of the thorax showing a heterogeneously enhancing soft tissue with erosion of the left ninth rib (red arrow). A heterogeneously enhancing mass with irregular margins is seen in the left breast (yellow arrow). (C) Coronal bone window sections of the thorax showing permeative destruction of the left ninth rib (red arrow). (D) Ultrasonography image showing a heterogeneous mass with irregular margins in the left breast Click here to view

Case 5

A 28-year-old girl, operated for mucinous adenocarcinoma of the rectum, presented with recurrence at the anastomotic site, a year after the surgery. She also presented with a lump in the left breast, increasing in size over a period of 4 months. Mammography revealed high-density masses with partially obscured margins containing coarse calcifications in the upper outer quadrant of the left breast [Figure 5]A, [Figure 5]B. A targeted ultrasound revealed hypoechoic masses with irregular margins and calcifications within, showing posterior acoustic shadowing [Figure 5]C and [Figure 5]D. A core biopsy with IHC revealed features of metastases from mucinous adenocarcinoma, positive for CK20 and negative for CK7. The patient was then treated with palliative chemotherapy but was lost to follow-up.

Figure 5 (A-D): (A and B) Left mammogram ((A) CC view and (B) MLO view) showing high-density masses (red arrows) with partially obscured margins containing coarse calcifications (yellow arrows and yellow asterisk) in the upper outer quadrant of the left breast. (C and D) Ultrasound images showing hypoechoic masses with irregular margins and coarse calcifications within, showing posterior acoustic shadowing (red arrow) at the 2 o'clock position in the left breast Click here to view

Case 6

A 47-year-old lady presented with a history of nasal obstruction, worsening over a period of 6 months associated with mild proptosis of the right eye. A contrast-enhanced CT of the paranasal sinuses revealed an enhancing soft tissue in the right maxillary sinus and nasal cavity causing bony erosion with orbital extension [Figure 6]A. Histopathologic examination of the tissue revealed Non-Hodgkin's lymphoma (NHL) of the diffuse large B-cell type. She received six cycles of chemotherapy for the same. During the course of treatment, she developed painless lumps in bilateral breasts. Mammography revealed multiple well-circumscribed high-density masses involving all quadrants of bilateral breasts [Figure 6]B and [Figure 6]C. Ultrasonography revealed multiple hypoechoic masses with irregular margins showing posterior acoustic shadowing [Figure 6]D. A core biopsy with IHC revealed B-cell type of NHL, positive for CD20, consistent with metastases. The chemotherapy regimen was modified. However, the patient died of fungal pneumonia after 6 months.

Figure 6 (A-D): (A) Contrast-enhanced coronal CT image of the paranasal sinuses showing an enhancing soft tissue (red asterisk) in the right maxillary sinus extending to the ethmoidal sinuses and nasal cavity causing bony erosion with orbital extension. (B and C) Bilateral mammograms ((B) MLO view and (C) CC view) showing multiple well-circumscribed high-density masses involving all quadrants of bilateral breasts (red asterisks). (D) Ultrasonography images showing darkly hypoechoic masses with indistinct margins (yellow asterisks) Click here to view

Discussion

The presence of a breast lesion in any patient with a known primary tumor elsewhere poses a diagnostic challenge to the clinician. The diagnostic approach first involves the differentiation of benign and malignant lesions, and if malignant, it is essential to know whether the lesion is primary or secondary since the treatment and prognosis differ greatly according to the nature of the lesion. Because of the rarity and unusual clinico-pathologic characteristics of breast metastases, it can be difficult to make an adequate diagnosis clinically and histologically.^[1] This is particularly true if the breast abnormality is the first presentation of unknown extramammary primary cancers metastatic to the breast.^[1],[2]

Metastases to the breast may occur years after the diagnosis of a primary cancer.^[2] Clinical differentiation from a primary carcinoma is challenging as majority of metastases present as rapidly growing, painless, palpable, firm breast masses.^[2] Radiology may play a critical role in aiding the diagnosis of metastatic breast disease. On mammography, metastases generally present as one or more well-circumscribed masses,^[3] commonly located in the upper outer quadrants without spiculations, calcifications, and features of desmoplastic reaction that characterizes majority of primary carcinomas.^[3],[4] Exceptions do occur, such as cases of mucinous adenocarcinomas of the rectum, as described in this article or metastatic ovarian carcinomas, in which metastatic lesions to the breast may reveal calcifications.^[5]Diffuseparenchymal involvement mimicking inflammatory carcinoma can be seen rarely, which was seen in the case of metastatic stomach cancer that we encountered. A similar pattern has been described in a previously described case series, in which metastatic stomach cancer presented with diffuse parenchymal infiltration instead of a discrete mass.^[3]

Ultrasonographic appearance of metastases may reveal solitary or multiple lesions, predominantly round or oval, with hypoechoic and solid echo patterns, with usually well-defined posterior margins. Multiple lesions are known to present with similar imaging findings.^[3],[4] On ultrasound, hematogenous metastases tend to have circumscribed margins without spiculations, calcifications, architectural distortion, or posterior acoustic shadowing.^[6] Lymphangitic metastases however manifest as diffuse skin and trabecular thickening because of obstruction of draining lymphatics.^[6] On ultrasonography, metastases to the breast are usually seen in the subcutaneous tissue, as noted in most of our cases or immediately adjacent to the parenchyma.

The primary sources of breast metastases in our case series were leiomyosarcoma, gastric carcinoma, Ewing's sarcoma, cervical carcinoma, colorectal carcinoma, and NHL.

The mammographic features of metastatic leiomyosarcoma to the breast, in our case, were similar to the one reported by Vizcaino et al.^[7] Both cases presented as discrete, well-circumscribed masses, though our patient had a single deposit and Vizcaino et al. reported multiple deposits.^[7]Two other cases of metastases from a primary leiomyosarcoma have been reported in literature;^[8],[9] however, the uterine origin of these deposits has not been documented.

Metastatic gastric adenocarcinoma to the breast has been reported to have variable imaging features. The case reported by Qureshi et al. did not present with suspicious imaging features and was diagnosed purely on histopathology.^[10] In the case reported by Cavazzini et al., the clinical features were similar to the ones reported by us; however, the imaging features differed. They reported an irregular poorly defined mass without calcifications, whereas our patient presented with a diffuse increase in parenchymal density with thickening of the nipple–areola complex.^[11]Kwak et al. reported two cases of metastatic signet ring cell carcinoma with increased parenchymal density on mammography mimicking inflammatory breast carcinoma, similar to our case; however, the organ of origin was not confirmed.^[12]

Vergier et al. reported a case of metastasis to the breast in a patient of epidermoid cervical carcinoma; however, the metastatic deposit in their case was found to have spiculated margins.^[13] Rarely, metastasis from cervical carcinoma may mimic an inflammatory breast cancer as reported by Ward et al.^[14] The imaging features in our case differed from both of these as the deposit in our case was a discrete, well-circumscribed mass.

Mihai et al. reported a case of breast metastasis suspected to be from a primary rectal carcinoma with imaging features not characteristic for malignancy, appearing as a well-defined mass on mammography; however, the organ of origin could not be confirmed.^[15] Li et al. and Zhang et al. reported cases of poorly differentiated adenocarcinoma of the rectum with metastasis to the breast presenting as an indistinctly marginated mass.^[16],[17] Ahmad et al. reported metastases to the breast from well-differentiated colo-rectal adenocarcinoma presenting as a partially well-defined nodule with intermediate type of microcalcifications on mammography, which suggested suspicious morphology favoring primary breast carcinoma; however, it later turned out to be metastatic deposit from a colo-rectal primary.^[18] Our case differed from the above cases as we encountered an extremely rare form of metastasis presenting with coarse calcifications, which differed from all of these.

Very few cases of metastases to the breast from Ewing' sarcoma have been documented. Örgüç et al. have reported a case of breast metastasis from Ewing's sarcoma of the right iliac bone in a 12-year-old girl, with imaging features similar to ours.^[19]

NHL of the breast is an extremely rare occurrence, accounting for about 0.5% of all breast malignancies and 1% of NHL,^[20],[21] and usually manifests as a secondary disease (i.e., in association with extramammary NHL).^[21] Surov et al. studied the imaging features of breast lymphoma in 36 patients. The most common mammographic finding in their study was multiple intramammary masses with circumscribed or microlobulated margins, similar to our case.^[21] The ultrasound features were also identical to ours, with most lesions appearing as hypoechoic, oval, or round masses with circumscribed margins. In the study by Yang et al., most cases of breast lymphoma however presented with a solitary breast mass with indistinct or irregular margins on mammography and ultrasound, which differed from the findings in our study.^[22]

In conclusion, our case series provides an overview of unusual cases of metastases to the breast from various extramammary malignancies. The occurrence of a breast mass in a patient with a known primary must be approached with caution, and the possibility of metastasis must be excluded, as the disease prognosis and course of management can be ascertained only after this distinction is made. 

 

Fwd: Bronchial artery embolization is an established intervention for management of recurrent massive hemoptysis

Bronchial artery embolization is an established intervention for management of recurrent massive hemoptysis

To:

Dealing with technical challenges in embolization of a rare aberrant left inferior bronchial artery arising from the left gastric artery in a patient with massive hemoptysis p. 476
Gaurav Gangwani, Ajit Yadav, Amit Dhamija, Arun Gupta
DOI:10.4103/ijri.IJRI_162_18  
Bronchial artery embolization is an established intervention for management of recurrent massive hemoptysis in a majority of patients. The source of bleeding in a majority of cases is systemic arteries – orthotopic bronchial arteries, anomalous bronchial arteries, or nonbronchial systemic collaterals. We report a case of an aberrant left inferior bronchial artery arising from the left gastric artery (LGA) in a patient with massive hemoptysis. Such origin from infradiaphragmatic vessels and specially left gastric arteries is very rare and needs to be considered by interventional radiologists and pulmonologists in case with hemoptysis disproportionate to supply by orthotopic arteries. Technical challenges were present in the present case in the form of an aneurysm in the aberrant artery and nontarget hepatic and gastric branches arising from LGA. Appropriate selection of hardware and embolic agents was done to deal with the clinical situation.
http://www.ijri.org/currentissue.asp?sabs=y

Fwd: Ganglion impar injection approaches and outcomes for coccydynia Foye PM, Sajid N, D'Onofrio GJ - Indian J Radiol Imaging

Ganglion impar injection approaches and outcomes for coccydynia Foye PM, Sajid N, D'Onofrio GJ - Indian J Radiol Imaging
To:

We praise your journal and authors Gonnade et al., on the excellent recent publication titled, "Ganglion impar block in patients with chronic coccydynia."[1] Their study of patients with chronic coccydynia (coccyx pain) showed that ganglion impar injections with local anesthetic block and corticosteroid significantly decreased pain and disability scores even at the maximum length of study follow-up, which was 6-month postinjection.

The authors clearly described injecting the ganglion impar via the sacrococcygeal junction. We would like to point out that other needle approaches can also be done, depending on the patient's anatomy. Specifically, interventional physicians should be aware of alternative approaches via the first[2] or second[3] intracoccygeal joint (between coccygeal vertebral bodies one and two, or between coccygeal vertebral bodies three and fourth, respectively). These approaches have been referred to as being transcoccygeal, intracoccygeal, or coccygeal transdiscal. These newer approaches have some potential advantages. First, since the sacrococcygeal joint is fused in 51% of humans,[4] these newer approaches provide access through joints that are more likely to be patent. Second, human cadaver studies have shown that the ganglion impar is usually located at the upper coccyx, rather than at the sacrococcygeal joint.[5]

We noted that the authors excluded from treatment any patients who had imaging abnormalities that would explain their tailbone pain. This surprised us since our experience is that coccydynia patients often respond extremely well to these impar injections, regardless of whether they do or do not have coccygeal imaging abnormalities. We would be very interested in the authors' thoughts on their exclusion criteria.

We hope our comments and the authors' reply will provide even more insights on relieving pain via these injections.
http://www.ijri.org/article.asp?issn=0971-3026;year=2018;volume=28;issue=4;spage=482;epage=483;aulast=Foye

Fwd: Drug-induced changes in dentate nuclei of cerebellum Aswani Y, Aswani N, Sharma R - Indian J Radiol Imaging

We read with great interest the article titled "Sequential MR imaging (with diffusion-weighted imaging) changes in metronidazole-induced encephalopathy" by Singh et al. in the April–June 2017 issue of the Indian Journal of Radiology and Imaging.[1] The article is highly informative and describes signal changes in splenium and dentate nuclei following metronidazole ingestion. In this article, we describe a few drugs that cause similar signal changes in the cerebellar dentate nuclei
http://www.ijri.org/article.asp?issn=0971-3026;year=2018;volume=28;issue=4;spage=480;epage=480;aulast=Aswani

Fwd: Role of proton MR spectroscopy in spinal cord lesions: A guarded espousal Agarwal A - Indian J Radiol Imaging

I read with great interest the article titled "3T proton MR spectroscopy evaluation of spinal cord lesions" by Sathyanathan et al. published in the July–September, 2018 issue of the Indian Journal of Radiology and Imaging.[1] The manuscript is well written and informative. The authors have narrated the MR spectroscopy (MRS) protocol and patterns in various intramedullary spinal lesions in a very efficient manner. However, I would like to make the following contributions and observations pertinent to the study.

In their study cohort of 50 patients, the authors have investigated spectral pattern on intramedullary spinal cord lesions. They designated four of them as schwannoma, which is an extramedullary lesion. Literature shows very few case reports of intramedullary schwannoma, which may be found in neurofibromatosis.[2],[3] Even in the subsequent discussion, the MRS pattern of these lesions is not elaborated. So, it will be of great help if authors could clarify my doubts in this regard.

The present study[1] defines the changes in the metabolites in different spinal lesions based on the deviation in their peak values from the normal spectra. In the previous few studies,[4],[5] the results have been expressed in terms of metabolite ratios, which is an absolute quantification method. Therefore, I would like to know about the authors' experience in evaluating the metabolite ratios and their feasibility pertaining to the study.

High signal-to-noise ratio is addressed in the present study[1] by the use of high magnetic field strength (3 T). However, there are spectral reliability indices such as Cramér–Rao lower bounds of each metabolite, mean, and standard deviation of the spectral line width, the coefficient of variations of the measurements, and the group average of the spectra.[5] These quality indicators can be used in future studies for enhancing the spectral quality and dependability.
http://www.ijri.org/article.asp?issn=0971-3026;year=2018;volume=28;issue=4;spage=481;epage=481;aulast=Agarwal