Anuradha Chandramohan

Causes of discordant or negative ultrasound of parathyroid glands in treatment naïve patients with primary hyperparathyroidism

OBJECTIVES To describe causes of discordant or negative parathyroid ultrasound and to assess factors influencing them. MATERIALS AND METHODS Retrospective review of patients who underwent parathyroidectomy between 2000 and 2012 was done. Imaging findings were compared with operative findings and pathology to identify discrepant (n=60; 32 negative, 28 incorrect) parathyroid ultrasounds. RESULTS Fifty (83.3%) patients had parathyroid adenoma, of which 10 (16.6%) were ectopic and three were double adenomas; 8 (13.3%) had multigland hyperplasia and two had parathyroid carcinoma. Discrepant reports were due to incorrect localisation in 8 (13.3%); difficulty in differentiating thyroid from parathyroid lesion in 12 (20%); large and small size in two and three patients, respectively; overcall in 5 (8.3%) and satisfaction of search in 7 (11.7%) patients. There was significant correlation between presence of multi-nodular goitre and incorrect reports (χ(2)=4.112, p=0.04). Experience of ultrasound operators performing initial and second look ultrasound was significantly different (p<0.0001). Second look ultrasound was concordant with surgical findings in 39(65%) patients; 21 (66%) patients with initially negative ultrasound and four out of five extra-mediastinal ectopic lesions. Ten patients with negative initial ultrasound had elongated parathyroid lesion. Scintigraphy was concordant in 44 (73.3%) patients and nine were ectopic. CONCLUSION Second look ultrasound performed by experienced operator for negative or discordant initial ultrasound of parathyroid is a useful strategy which will improve the accuracy of parathyroid ultrasound. Being able to differentiate thyroid from parathyroid lesion is a factor which will influence performance of parathyroid ultrasound.

Best MRI predictors of complete response to neoadjuvant chemoradiation in locally advanced rectal cancer

OBJECTIVE To identify the MRI parameters which best predict complete response (CR) to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC) and to assess their diagnostic performance. METHODS This was a prospective study of pre- and post-CRT MRI and diffusion-weighted imaging (DWI) of 64 patients with LARC who underwent neoadjuvant CRT and subsequent surgery. Histopathological tumour regression grade was the reference standard. Multivariate regression analysis was performed to identify the best MRI predictors of CR to neoadjuvant CRT, and their diagnostic performance was assessed. RESULTS The study cohort comprised 48 males and 16 females (n = 64), with mean age of 49.48 ± 14.3 years, range of 23-74 years. 11 patients had pathological complete response. The following factors predicted CR on univariate analysis: low initial (pre-CRT) tumour volume on T2 weighted high-resolution (HR) images and DWI, tumour volume-reduction rate (TVRR) of >95% on DWI and CR on post-CRT DWI (ydwiT0) as assessed by the radiologist. However, the best MRI predictors of CR on multivariate regression analysis were CR on post-CRT DWI (ydwiT0) as assessed by the radiologist and TVRR of >95% on DWI, and these parameters had an area under the curve (95% confidence interval) of 0.881 (0.74-1.0) and 0.843 (0.7-0.98), respectively. The sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of DWI in predicting CR was 81.8%, 94.3%, 75%, 96.1% and 76%; the sensitivity, specificity and accuracy of TVRR of >95% as a predictor of CR was 80%, 84.1% and 64.1%, respectively; however, this difference was not statistically significant. The interobserver agreement was substantial for ydwiT0. CONCLUSION Visual assessment of CR on post-CRT DWI and TVRR of >95% on DWI were the best predictors of CR after neoadjuvant CRT in patients with LARC, and the former being more practical can be used in daily practice. ADVANCES IN KNOWLEDGE In rectal cancer, ydwiT0 as assessed by the radiologist was the best and most practical imaging predictor of CR and scores over standard T2W HR images.

Role of conventional and diffusion weighted MRI in predicting treatment response after low dose radiation and chemotherapy in locally advanced carcinoma cervix.

BACKGROUND AND PURPOSE To assess the diagnostic performance of conventional and diffusion weighted (DWI) magnetic resonance imaging (MRI) in predicting response in locally advanced cervical cancer. MATERIALS AND METHODS Total 24 patients with stage IIB-IIIB squamous cell carcinoma cervix were treated with initial two cycles of paclitaxel and carboplatin and concurrent low dose radiotherapy prior to standard chemoradiation. Response was assessed clinically and radiologically after 3 weeks of initial treatment. Volumetric and functional parameters derived from conventional and diffusion weighted MRI, due to treatment were measured. RESULTS Significant reduction of GTV was noted in MRI (54 cm(3) vs. 11 cm(3), p < 0.01) and DWI (44 cm(3) vs. 6 cm(3), p < 0.01, ΔADC = 0.49 × 10(-3)mm(2)/sec, p < 0.01) after treatment. Tumor volume reduction rate (TVRR) in DWI was significantly higher in pathological good responders (p = 0.03). In this group both mean post treatment apparent diffusion coefficient (ADC) value and ΔADC were significantly higher (p = 0.01 and p = 0.03). ADC was a good predictor for pathological response (area under receiver operating characteristic curve (ROC) 0.814). CONCLUSION TVRR (DWI) and ΔADC can be used as a predictor of early pathological response. Complete response based on DWI, could be a useful predictor of long term disease control.

Acute pancreatitis and hyperparathyroidism: A case series

Primary hyperparathyroidism is a rare cause of acute pancreatitis. Five consecutive patients with acute or recurrent acute pancreatitis and primary hyperparathyroidism were included. All patients had elevated serum calcium on admission and high levels of circulating parathyroid hormone. Both ultrasonography and Sestamibi scan was used to localize parathyroid adenoma. Except for one, all patients underwent parathyroidectomy and postoperative histology was consistent with parathyroid adenoma. One patient died while on treatment. Metabolic causes of acute pancreatitits, though uncommon, are important as early recognition helps management and prevents recurrence.

Is TIRADS a practical and accurate system for use in daily clinical practice

Aim: To assess the positive predictive value (PPV) and inter-observer agreement of Thyroid Imaging Reporting and Data System (TIRADS) as described by Kwak et al. Materials and Methods: This was a prospective study wherein ultrasound was performed by two radiologists on patients with thyroid nodules >1 cm. The third radiologist interpreted archived images. Ultrasound features and TIRADS category were compared with cytology and surgical histopathology. PPV was calculated for all readers’ combined assessment. Inter-observer agreement was calculated using linear weighted kappa. Results: A total of 238 patients with 272 nodules of mean size 2.9 ± 1.7 cm were included. PPV for malignancy was 6.6%, 32%, 36%, 64%, 59%, and 91% for TIRADS 2, 3, 4a, 4b, 4c, and 5 categories, respectively. Inter-observer agreement was substantial [kappa (k) = 0.61-0.80] for assessment of nodule echogenicity, margins, calcification, and shape and good (k = 0.570, P < 0.001) for assessment of composition of the thyroid nodules. Overall agreement between observers was substantial for assigning TIRADS category [multi-rater weighted kappa coefficient (wt k) = 0.721, P < 0.001]. Conclusions: TIRADS is a simple and practical method of assessing thyroid nodules with high PPV and good inter-observer agreement.

US as a primary tool in the work-up of malrotation

Sir, We wish to compliment Dr. Yousefzadeh [1] for his efforts in bringing down radiation dose to pediatric patients during diagnostic work-up of suspected malrotation. However, a few issues need to be addressed before we can consider USG as the gold standard in evaluation of patients suspected of having malrotation. From a medicolegal viewpoint, the false-negative and false-positive examinations need to be ascertained. The falsenegative examinations would be patients where US did not reveal malrotation. Were these children followed up and did any of them require surgery? How long (range andmean value in days/months) was the period of follow-up? We believe that the author’s proposition of using US as an effective screening tool to exclude malrotation and thereby the risk of future midgut volvulus is an over-simplification. This is because malrotation of gut can occur in various permutations and combinations and US will work only for the garden variety malrotation, approximately 60% of which includes the nonrotation of gut and a few forms of incomplete rotations. In cases of partial rotation of duodenum (22%) and the small percentage (2%) of malrotation where duodenum is normally positioned, US will still show the third part of duodenum interposed between the superior mesenteric artery (SMA) and aorta, thus malrotation may be missed [2, 3]. In reversed rotation, the transverse colon is in between the SMA and aorta and the third part of duodenum is anterior to the SMA. On US, the transverse colon may be mistaken for duodenum as it can be difficult to differentiate between duodenum and transverse colon, resulting in malrotation being missed. False-positive diagnosis of malrotation on an upper GI contrast study can occur because of failure to identify the duodenum as a normal variant [4–6]. In this condition, the position of the third part of duodenum is higher than usual and the sonographer may miss that segment of duodenum. It is pertinent to note that the sonographic features of duodenum inversum are not described in literature. Apart from the technical difficulties, an important issue is observer experience. US is known to be operatordependent and expertise in neonatal abdominal sonography is not readily available even in developed countries. Thus the risk of false-positive examinations is likely to be much higher unless you have the sonographic experience and expertise that Dr. Yousefzadeh is lucky to have! Last, but not the least, preferences of the treating surgeon need to be taken into consideration. In a situation where even the radiologists are not comfortable with US, it is unlikely that surgeons are going to risk depending on sonographic findings. Thus, we conclude that although US may be an excellent modality for diagnosis of malrotation in expert hands, its role in less-experienced organizations should be explored using prospective studies.

Posterior gastric diverticulum mimicking adrenal adenoma on imaging

A 63-year-old man on a permanent pacemaker for complete heart block presented with one episode of haemoptysis. Clinical examination of the thorax was unremarkable. A contrast-enhanced CT scan showed normal lungs and a well-defined lesion in the left adrenal gland, apparently separated from the posterior wall of the stomach in all the images. It measured 3 cm with a density of 6–10 Hounsfield units (HU; figure 1). Postcontrast washout was not performed as the HU density was low. In view of …

Radiological predictors of complete cytoreduction in 59 patients with peritoneal mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy at a UK referral centre

OBJECTIVE To assess the imaging features of peritoneal mesothelioma and identify key anatomical sites that aid patient selection for complete cytoreduction. METHODS Pre-operative imaging of 59 (32 males, 27 females) patients who underwent cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) for histologically proven peritoneal mesothelioma [36 malignant peritoneal mesothelioma, 23 cystic mesothelioma were reviewed. Imaging findings were correlated with surgical outcome. Best imaging predictors of complete cytoreduction, n = 22 and major tumour debulking, n = 12 were assessed. RESULTS Most patients (88.9%) had diffuse peritoneal disease with mean radiological peritoneal cancer index of 18 ± 12 (range 2-39). Disease in the lesser omentum (n = 10), porta hepatis (n = 8), perigastric area (n = 5), mesentery (n = 25), small bowel (n = 17), hydronephrosis (n = 1), concurrent pleural disease (n = 2), lymph nodes (n = 1) and abdominal wall disease (n = 4) was considered unfavourable. While 78.9% of patients who underwent complete cytoreduction had no disease at unfavourable sites, 75% of those who underwent MTD did have disease at these sites. There was significant difference in the radiological peritoneal cancer index, severity of upper abdominal disease, small bowel and mesenteric involvement between patients who underwent complete cytoreduction and MTD for malignant peritoneal mesothelioma. Complete cytoreduction was not achieved in the presence of a rind of soft tissue around the small bowel (p = 0.016) and was unlikely in the presence of large volume upper abdominal disease (p = 0.06). CONCLUSION Involvement of key anatomical sites such as small bowel serosa and large volume upper abdominal disease reduced the likelihood of achieving complete cytoreduction in patients with malignant peritoneal mesothelioma. Advances in knowledge: Demonstration of small bowel disease and large volume upper abdominal disease on imaging in patients with malignant peritoneal mesothelioma can be used to identify patients who may not benefit from cytoreductive surgery.

Intravascular mesenchymal chondrosarcoma.

A 25-year-old woman with low backache underwent a computed tomography scan, which showed a heterogeneously enhancing paravertebral mass with areas of fine, granular calcification along the course of left iliac vein (Fig a). The mass was heterogeneous with fine hypointense foci on T2-weighted magnetic resonance imaging (Figs b, c) that corresponded to the calcifications seen on computed tomography. The patient underwent resection of the mass. Histology (Fig d; hematoxylin-eosin stain, 200) showed highly cellular, round to spindle-shaped tumor cells with