Gnana Kumar

Malignant transformation of mesenchymal hamartoma of the liver: Case report and review of the literature

Here the first case in the literature of both mesenchymal hamartoma and malignant mesenchymoma occurring in a 6-year-old male child, at different times and at different sites in the liver, and also the possible malignant transformation of a mesenchymal hamartoma is reported. The tumor developed from a lesion in the right lobe that was overlooked initially during a left lateral segmentectomy at 18 months of age for a mesenchymal hamartoma. Malignant mesenchymoma is a rare and aggressive tumor. The origin of this tumor is not well understood. There has been no direct support to the hypothesis that malignant mesenchymoma may be the malignant counterpart of mesenchymal hamartoma. The authors provide clinical and histopathologic evidence in our case that suggests the possibility of malignant mesenchymoma arising from a mesenchymal hamartoma. This case emphasizes the need for complete removal of mesenchymal hamartoma and the need for long-term follow-up to detect multifocal lesion or malignant transformation.

A comparison between low-dose and standard-dose non-contrasted multidetector CT scanning of the paranasal sinuses.

Purpose To compare the image quality of the low-dose to the standard-dose protocol of MDCT scanning of the paranasal sinuses, based on subjective assessment and determine the radiation doses to the eyes and thyroid gland and dose reduction between these two protocols. Materials and Methods 31 adult patients were scanned. Prior to scanning, thermoluminescent dosimeters (TLDs) were placed at 4 sites: outer canthus of right eye, outer canthus of left eye, inner canthus and anterior neck (thyroid gland). Every patient was scanned twice using the standard-dose protocol (100mAs) followed by the low-dose protocol (40mAs). The images were reviewed by 3 radiologists. Wilcoxon test was used as the test of significance for the image quality assessments. The paired sample t-test was used as the test of significance for the analysis of the radiation doses measured by the TLDs. Results Of the 30 patients selected for analysis, this study showed no significant difference in the scores for the diagnostic image quality and the anatomical structures assessments between the two protocols. The average calculated mean entrance surface doses and standard deviation for the standard-dose and low-dose protocols were 12.40±1.39 mGy and 5.53±0.82 mGy respectively to the lens and 1.03±0.55 mGy and 0.63±0.53 mGy respectively to the thyroid gland. Conclusion The reduction of mAs from 100 to 40 resulted in a significant reduction of the radiation doses to the lens and thyroid gland by 55.4% and 38.8% respectively without causing any significant effect to the diagnostic image quality and assessment of the anatomical structures.

Post-traumatic arachnoiditis: an unusual cause of Brown-Sequard syndrome

Abstract. Brown-Sequard syndrome (BSS) is a unilateral cord injury characterised by an ipsilateral motor deficit with contralateral pain and temperature hypoaesthesia. Although there are a variety of causes, the majority of cases are generally of neoplastic origin or are traumatic in origin. We describe a rare cause of Brown-Sequard syndrome as a result of post-traumatic arachnoiditis. Magnetic resonance imaging with the use of thin-slice high-resolution constructive interference in steady state (CISS) and T2-weighted spin-echo sequence were used to demonstrate the cause and appearance of the lesion in the spinal canal and was useful in the assessment and management of the patient. This case illustrates the usefulness of the CISS sequence in MRI for elucidating arachnoiditis.

Evaluation of radiation dose and image quality following changes to tube potential (kVp) in conventional paediatric chest radiography

Purpose A study of radiation dose and image quality following changes to the tube potential (kVp) in paediatric chest radiography. Materials and Method A total of 109 patients ranging from 1 month to 15 years were included in two phases of the study. Phase 1 investigated the range of entrance surface air kerma (ESAK) values received from patients exposed to the existing exposure factors. In the second phase, new exposure factors using recommended values of tube potential (kVp) with reduced mAs were used. ESAK values were measured using thermoluminescent dosemeters (TLDs). Image quality in both phases was evaluated using image quality criteria proposed by the Council of the European Communities (CEC). Results of both techniques were analysed for any differences. Results The overall mean ESAK before the changes was 0.22 mGy (range: 0.05-0.43) Following changes in tube potential, the overall mean reduced to 0.15 mGy (range: 0.03-0.38), a significant reduction by 34%. The interquartile range was reduced from 45% to 40%. However, doses to those below a year in age still remained high. Assessment of image quality was found to have no significant differences as far as the two techniques used were concerned. However, higher image scores were achieved using higher kVps. Conclusion Significant dose reduction was achieved through appropriate changes in tube potential and reduction of mAs without any loss in image quality.

Use of 100 kV versus 120 kV in computed tomography pulmonary angiography in the detection of pulmonary embolism: effect on radiation dose and image quality.

OBJECTIVE To determine the effective radiation dose and image quality resulting from 100 versus 120 kilovoltage (kV) protocols among patients referred for computed tomography pulmonary angiography (CTPA). METHODS Sixty-six patients with clinical suspicion of pulmonary embolism (PE) were prospectively enrolled. Two CTPA protocols (group A: n=33, 100 kV/115 mAs; group B: n=33, 120 kV/90 mAs) were compared. Two experienced radiologists assessed image quality in terms of diagnostic performance and effect of artefacts. Image quality parameters [CT attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)] and effective radiation dose between the two protocols were compared. RESULTS The contrast enhancement in central and peripheral pulmonary arteries was significantly higher in group A than in group B (P<0.001) with the identical SNR (P=0.26), whereas the CNR was significantly higher in group A than in group B (P<0.001). The effective radiation dose for the 100 and 120 kV scans was 3.2 and 6.8 mSv, respectively. CONCLUSIONS Reducing the tube voltage from 120 to 100 kV in CTPA allows a significant reduction of radiation dose without significant loss of diagnostic image quality.

Infratentorial benign cystic meningioma mimicking a hemangioblastoma radiologically and a pilocytic astrocytoma intraoperatively: a case report

IntroductionCystic meningiomas are rare variants of meningiomas; they can pose a radiological diagnostic dilemma.Case presentationWe present a rare case of a 30-year-old Chinese woman with a histopathological diagnosis of infratentorial cystic meningioma (World Health Organization Grade 1) in which the features in imaging modalities were suggestive of a hemangioblastoma. Intraoperatively, however, the gross macroscopic features were more in keeping with a pilocytic astrocytoma.ConclusionIn benign cystic meningiomas, particularly the infratentorial variety, radiological findings utilizing the various imaging modalities and intraoperative impressions may not be reflective of or in keeping with the final histopathological diagnosis.

Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique.

Objective: To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique. Patients and Methods: Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups. Results: 84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts. Conclusion: The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta.

Gartner duct cyst in pregnancy presenting as a prolapsing pelvic mass.

Gartner duct cysts are the remnants of the Wolffian duct and they are rarely seen in adulthood. We present a case of a pregnant patient with a prolapsing vaginal mass. A diagnosis of Gartner duct cyst was made after MRI was performed. The Gartner duct cyst was drained when the patient went into labour allowing vaginal delivery to be performed.

Intrasellar pituitary mucocele: diagnostic dilemma

Abstract Isolated intrasellar pituitary mucocele following transsphenoidal sinus surgery is extremely rare. The clinical features resemble a pituitary tumor, therefore careful radiological interpretation is crucial to reach the correct diagnosis. We report a case of intrasellar mucocele who had transsphenoidal sinus surgery performed 15 years prior.

Mastoiditis secondary to mycobacterium abscessus imaged with gallium-67 scintigraphy

Atypical mycobacterium is rarely seen as a cause of chronic mastoiditis but has been increasingly recognized over the past few years. Mycobacterium abscessus is the most pathogenic and chemotherapy-resistant, rapid-growing mycobacterium of all the four groups. This paper presents a case of a 57-year-old woman who had chronic mastoiditis with recurrent exacerbations. The initial computed tomography (CT) findings showed the presence of an inflammatory process and she was treated with the appropriate antibiotics. The patient subsequently underwent a tissue biopsy when she presented with another exacerbation. At this time, the CT scan did not identify the ongoing exacerbation, but the Gallium-67 scintigraphy did.