Nikhil H. Merchant

Trans-abdominal ultrasound (US) and magnetic resonance imaging (MRI) correlation for conformal intracavitary brachytherapy in carcinoma of the uterine cervix

PURPOSE Trans-abdominal ultrasonography (US) is capable of determining size, shape, thickness, and diameter of uterus, cervix and disease at cervix or parametria. To assess the potential value of US for image-guided cervical cancer brachytherapy, we compared US-findings relevant for brachytherapy to the corresponding findings obtained from MR imaging. MATERIALS AND METHODS Twenty patients with biopsy proven cervical cancer undergoing definitive radiotherapy with/without concomitant Cisplatin chemotherapy and suitable for brachytherapy were invited to participate in this study. US and MR were performed in a similar reproducible patient positioning after intracavitary application. US mid-sagittal and axial image at the level of external cervical os was acquired. Reference points D1 to D9 and distances were identified with respect to central tandem and flange, to delineate cervix, central disease, and external surface of the uterus. RESULTS Thirty-two applications using CT/MR compatible applicators were evaluable. The D1 and D3 reference distances which represent anterior surface had a strong correlation with R=0.92 and 0.94 (p<0.01). The D2 and D4 reference distances in contrast, which represent the posterior surface had a moderate (D2) and a strong (D4) correlation with R=0.63 and 0.82 (p<0.01). Of all, D2 reference distance showed the least correlation of MR and US. The D5 reference distance representing the fundal thickness from tandem tip had a correlation of 0.98. The reference distances for D6, D7, D8, and D9 had a correlation of 0.94, 0.82, 0.96, and 0.93, respectively. CONCLUSIONS Our study evaluating the use of US, suggests a reasonably strong correlation with MR in delineating uterus, cervix, and central disease for 3D conformal intracavitary brachytherapy planning.

Reporting and validation of gynaecological Groupe Euopeen de Curietherapie European Society for Therapeutic Radiology and Oncology (ESTRO) brachytherapy recommendations for MR image-based dose volume parameters and clinical outcome with high dose-rate brachytherapy in cervical cancers: a single-institution initial experience.

Objective: The objectives are to report the dosimetric analysis, preliminary clinical outcome, and comparison with published data of 3-dimensional magnetic resonance-based high dose rate brachytherapy (BT) in cervical cancer. Materials and Methods: The data set of 24 patients with cervical cancer treated with high dose-rate brachytherapy applications was analyzed. All patients received radiation with or without chemotherapy (10 patients received concomitant chemoradiation). Point A, International Commission on Radiation Units and Measurement (ICRU) point doses, and Groupe Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology dose volume parameters, namely, high-risk clinical target volume (HR-CTV), D90 and D100 doses, and dose to D0.1cc and D2cc, for rectum, bladder, and sigmoid, were calculated and correlated. Results: Mean ± SD HR-CTV was 45.2 ± 15.8 cc. The mean ± SD point A dose was 73.4 ± 4.5 Gy (median, 74.3 Gy) total biologically equivalent dose in 2 Gy per fraction (EQD2), whereas mean ± SD D90 doses were 70.9 ± 10.6 GyEQD2 (median, 68). The mean ± SD ICRU rectal and bladder points were 63.5 ± 8.1 and 80.4 ± 34.4 GyEQD2, respectively. The D0.1cc and D2cc for rectum were 66.0 ± 9.9 GyEQD2 (median, 64.5) and 57.8 ± 7.7 GyEQD2 (median, 58.8), for bladder 139.1 ± 54.7 GyEQD2 (median, 131.9) and 93.4 ± 24.6 GyEQD2 (median, 91), and sigmoid were 109.4 ± 45.2 GyEQD2 (median, 91) and 74.6 ± 19.6 GyEQD2 (median, 69.6). With a median follow-up of 24 months, 3 patients had local nodal failure, 1 had right external iliac nodal failure, and 1 had left supraclavicular nodal failure. Conclusions: The 3-D magnetic resonance image-based high dose-rate brachytherapy approach in cervical cancers is feasible. In our experience, the HR-CTV volumes are large, and D0.1cc and D2cc doses to bladder and sigmoid are higher than published literature so far.

18-fluoro-deoxy-glucose positron emission tomography with computed tomography-based gross tumor volume estimation and validation with magnetic resonance imaging for locally advanced cervical cancers.

Purpose Anatomy and morphology–based imaging is routinely used for radiotherapy purpose to deliver precision treatment. There is an interest in using information from functional imaging for conformal radiation therapy planning. These functional imaging techniques need to be validated rigorously before their routine use. We attempted to evaluate and validate the use of 18-fluoro-deoxy-glucose positron emission tomography with computed tomography (18FDG PET-CT) on primary tumor of the cervical carcinoma, with an aim of arriving at a cutoff maximum standardized uptake value (SUVmax) at which the tumor volume correlates best with magnetic resonance imaging (MRI). This observational study was a part of an ethics committee–approved study evaluating pretreatment MRI and FDG PET-CT. Materials and Methods Patients’ biopsy-proven cervical carcinomas (stages IIB and IIIB) were included in this study and underwent pretreatment MRI and FDG PET-CT as per institutional protocol. Volumes of the disease at the cervix on the MR image were calculated. Volumes at the FDG PET-CT scan at different percentages of SUVmax were auto contoured. Volume at MRI was correlated with each different percentage cutoff of the SUVmax. Results Data of 74 patients were available for the study. The mean (SD) SUVmax of the primary tumor was 15.7 (7.0). The mean MRI volume correlates significantly (P < 0.001) with 30% and 35% of SUVmax values with good correlation according to the Pearson bivariate correlation (r = 0.79 each). The mean difference between MRI and PET volumes was least with 30% SUVmax. Conclusions 18FDG PET-CT SUV-based primary tumor volume estimation at 30% to 35% of SUVmax values correlates significantly with the criterion standard MR volumes for primary cervical tumor with squamous histology in our population.

Malignant brachial plexopathy: A pictorial essay of MRI findings

For imaging, the brachial plexus is a technically and anatomically challenging region of the peripheral nervous system. MRI has a central role in the identification and accurate characterization of malignant lesions arising here, as also in defining their extent and the status of the adjacent structures. The purpose of this pictorial essay is to describe the MRI features of primary and secondary malignant brachial plexopathies and radiation-induced brachial nerve damage.

18 F-FDG avid lesion due to coexistent fibrous dysplasia in a child of embryonal rhabdomyosarcoma: source of false positive FDG-PET.

With increasing use of 18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in the current oncological practice, there is a growing body of evidence of false positive scans due to various benign conditions. In this communication we present intensely avid 18 F-FDG uptake in fibrous dysplasia of right tibia in a 12-year-old child suffering from embryonal rhabdomyosarcoma (ERMS) that could have been easily mistaken to be a metastatic focus if not carefully correlated. The patient was a case of ERMS (presenting with left cervical mass with intrathoracic extension) who was treated successfully with chemotherapy and was referred for FDG-PET to evaluate the disease status. His whole body survey was unremarkable except for an intensely avid FDG uptake (SUV max 8.5) in shaft of right tibia. The scan was extended up to foot in view of the fact that a prior bone scan had shown a focal uptake in the similar location. Efforts were undertaken to elucidate the exact etiopathology of the aforementioned 18 F-FDG uptake because the rest of the whole body survey was unremarkable. A plain radiograph (both anteroposterior and lateral views) of the right tibia showed patchy sclerosis involving the middle diaphysis of the right tibia suggesting a fibrous defect. The computed tomography (CT) scan of the same region showed cortical thickening and increased density within the medullary cavity in the shaft of the tibia. A histopathological diagnosis was sought for and the lesion was subsequently proven to be fibrous dysplasia by histopathology of the bone piece obtained from the right tibial lesion by J needle biopsy. The present case is a useful addition to the current body of literature of false positive 18 F-FDG-PET study due to a benign skeletal pathology and underscores the importance of high index of suspicion and careful clinicoradiopathologic correlation, whenever one comes across such an unusual PET finding.

Unusual late sequel of ruptured distal tendon of biceps brachii mimicking a soft-tissue tumor

ObjectiveWe report a rare case of chronic, neglected rupture of the distal biceps brachii which presented with gradually increasing swelling over the left lower arm. Fine-needle aspiration cytology was reported as indicative of a soft-tissue neoplasm. Computed tomography and magnetic resonance imaging were unable to rule out a neoplastic mass. Final histopathology after surgical excision revealed a reparative process.ConclusionSuch a presentation of ruptured biceps brachii wherein the clinicoradiological features are misleading and suggestive of a soft-tissue tumor is quite unusual.

Oxidised regenerated cellulose: an unusual cause of paraplegia following oesophagectomy

Oesophageal resection after neoadjuvant therapy is the treatment of choice in localized oesophageal cancer. Common complications after oesophagectomy include pulmonary infection and anastomotic leaks. Paraplegia or paraparesis after oesophagectomy is an extremely uncommon occurrence and has not been reported in medical literature. Possible causes include injury to the spinal cord due to epidural catheter insertion, epidural haematoma and anterior spinal artery thrombosis. Pressure on the spinal cord due to migrated oxidised regenerated cellulose (ORC) is an extremely rare cause. Meticulous haemostasis at the costovertebral angle with a combination of pressure and electrocautery is advocated to prevent this rare but catastrophic complication. We describe a middle aged woman who developed post-thoracotomy paraplegia following ORC compression on the spinal cord.

Diagnostic dilemmas in fine needle aspiration cytology of an ectopic kidney: a case report.

BACKGROUND Congenital anomalies are easily diagnosed on radiology and rarely have an unusual presentation requiring an invasive diagnostic procedure. Fine needle aspiration cytology (FNAC), though a well-established diagnostic technique for abdominal and retroperitoneal lesions, is fraught with several challenges and pitfalls. CASE We report a case of a 39-year-old woman with an ectopic kidney presenting as an abdominal mass. On FNAC the cellular aspirate was misinterpreted as a paraganglioma or metastatic carcinoma. CONCLUSION This case highlights the fact that on FNAC, normal cellular components, especially from the kidney, provide a significant pitfall for overdiagnosis, potentially resulting in unnecessary surgical explorations.