NIMG-66. USING 68GA-DOTATATE PET FOR POSTOPERATIVE GAMMA KNIFE RADIOSURGERY PLANNING IN PATIENTS WITH MENINGIOMA

BACKGROUND Patients with meningiomas are typically treated with maximal safe surgical resection. After subtotal resection or at the time of tumor recurrence, stereotactic radiosurgery (SRS) is often used as the treatment of choice. While magnetic resonance imaging (MRI) is typically used for SRS target delineation, differentiating tumor growth from postoperative change can be challenging. 68Ga-DOTATATE, a positron emission tomography (PET) radiotracer targeting the somatostatin receptor type 2 (SSTR2), has been shown to be a reliable biomarker of meningiomas. METHODS We present a consecutive case series of 13 patients with pathology-proven meningioma who received a 68Ga-DOTATATE PET prior to SRS between April 2019 and April 2021. Treatment planning was done at first using MRI only. The DOTATATE-PET images were then used to assess the accurate identification of tumor. RESULTS Ten of the patients had WHO grade 2 meningioma and three patients had WHO grade 1 tumor. Nine patients had recurrent meningiomas and four patients had newly diagnosed disease. Overall, the 68Ga-DOTATATE PET scan revealed additional tumor beyond what was seen on MRI in 5/13 patients. The SRS plan was changed to intensity-modulated radiation therapy (IMRT) for three patients and to octreotide injection in one patient. In one patient, after 68Ga-DOTATATE PET identified previously unrecognized recurrent meningioma in the resection cavity, SRS was performed. In three others, questionable tumor recurrence was seen on MRI, and then confirmed on 68Ga-DOTATATE-PET, but patient observation only was continued due to the small lesion size. CONCLUSION Incorporation of 68Ga-DOTATATE PET data changed SRS treatment in 5/13 our patients with meningioma after prior surgery. We have made this a routine part of our treatment planning and we recommend this method to optimize the use of SRS or RT in these patients. Further data collection is ongoing.

First Report of Alternaria alternata Causing Leaf Spot on Menisper-mum dauricum DC. in China

Menispermum dauricum DC. is an ornamental plant used in traditional Chinese medicine. (Tang et al. 1992). In September 2019, a leaf spot on M. dauricum DC. was first found in a medicinal plant plantation in Harbin city (45.80°N, 126.53°E), Heilongjiang Province, China. The incidence was 76-90% on the 0.02 ha plantation. The initial symptoms were irregular black and brown spots on the leaves. The lesions expanded and coalesced, eventually leading to blight. Fresh leaf samples from ten M. dauricum plants with typical symptoms were collected. The areas of leaf between symptomatic and healthy tissue (5㎜×5㎜) were cut and surface disinfeated in 75% ethanol for 2 min, and with 1% HgCl2 for 1 min, and then rinsed three times with sterile water. Small lesion pieces were incubated on potato dextrose agar (PDA) for 7 days at 25℃, in the dark. Ten fungal isolates were obtained and transferred onto new PDA and potato carrot agar (PCA) plates to establish pure cultures. After 8 days, the colonies on PDA were 75-86㎜ in diameter, circular, with distinct concentric rings and a whitish aerial-mycelium margin, cottony, light gray to dark bluish brown. The colonies on the PCA were olive-green and bordered by white aerial hyphae. A total of 150 conidia were single or in short chains, obclavate, oval or inverted pear, light brown to brown, smooth or slightly spiny, with 1 to 6 transverse septa, 0 to 4 longitudinal or oblique septa, not narrow or slightly narrowed at the separation, 22.5-42.5×7.5-15.5㎛, and rostrate. Conidiophores were simple, erect, or ascending, dark brown, geniculate, septate, and with one or several conidial scars, 32.5-77.5×3.0-5.0㎛. Beaks were columnar or conical, 7.5-22.5×2.5-3.5㎛. Morphologically, all ten isolates were most similar to Alternaria alternata (Simmons 2007). For further identification of the fungus at the molecular level, internal transcribed spacer rDNA regions (ITS), RNA polymerase second largest subunit gene (RPB2) and Alternaria major allergen (Alt a 1) were amplified and sequenced using the primers ITS1 and ITS4, RPB2-5F2 and RPB2-7CR, Alt-for and Alt-rev (Woudenberg et al. 2015). The resulting sequences were deposited in GenBank (ITS: MT995193, MZ150794, RPB2: MT999483, MZ170963, Alt a 1: MT802122, MZ170962). BLAST search of these sequences showed 99%-100% homology with the ITS (FJ196306), RPB2 (KC584375) and Alt a 1 (KT315515) of the type strain CBS 916.96 of A. alternata, respectively. Thus, the fungus was identified as A. alternata based on the morphology and molecular analysis. For the pathogenicity test, spore suspensions (1×106 spores/mL) of the representative isolates BFG001 and BFG002 were sprayed onto the leaves of six healthy plants, separately. As a control, six plants were treated with sterile distilled water. The plants used in the experiment were covered with plastic bags and incubated at 25℃ for 10 days. Eight days after inoculation, irregular, slightly sunken black leaf spots appeared at the leaf margin. The experiment was repeated three times with the same method. The same fungus was successfully re-isolated from the leaves of the inoculated plants, fulfilling Koch’s postulates. No symptoms were observed on control plants. To our knowledge, this is the first report of leaf spot disease on M. dauricum DC. caused by A. alternata in the world. The appearance of leaf spot disease reduces the yield and quality of Chinese medicinal materials. This report has laid the foundation for the further research and control of leaf spot disease.

Pilomatrixoma and its Imitators

Introduction: Pilomatrixomas are benign neoplasms derived from hair follicle matrix cells. They are among the most common soft tissue head and neck tumors of childhood. Pilomatrixomas are typically isolated, slow-growing, firm, nontender masses that are adherent to the epidermis but mobile in the subcutaneous plane. This clinical presentation is so characteristic that many experienced surgeons will excise suspected pilomatrixomas without prior imaging. We reviewed the results of this approach to determine whether physical examination alone differentiates pilomatrixomas from other similar soft tissue lesions of the pediatric head and neck. Methods: Computerized review of all pilomatrixomas over a 20-year period in a single academic pediatric otolaryngology practice. Results: 18 patients presented to our pediatric otolaryngology practice between 2001 and 2021 with historical and physical findings consistent with pilomatrixoma. Of the 18 patients, 7 were male and 11 were female. Ages ranged from 1.5 to 14 years, with a mean of 7.5 years. Most of the lesions (12) were located in the head and face, while the rest (6) were found in the neck. All patients were treated with complete surgical excision. Pathology confirmed pilomatrixoma in 15 patients. The remaining 3 children were found to have an epidermal inclusion cyst, a ruptured trichilemmal cyst, and a giant molluscum contagiosum lesion, respectively. One additional patient presented with a small lesion of the auricular helix that was thought to be a dermoid cyst, but proved to be a pilomatrixoma on histologic examination. Discussion: As pilomatrixomas are common and have a very characteristic presentation, surgical excision without prior diagnostic imaging will lead to correct treatment in the majority of cases. High resolution ultrasonography can help to confirm the diagnosis preoperatively, but is not definitive in large case series. Most of the cystic lesions that imitate pilomatrixoma will ultimately require surgical excision.

Isolated abducens nucleus syndrome due to pontine tegmentum infarction

Introduction: Abnormalities of horizontal gaze could be caused by damage of the abducens nucleus due to ischemic lesion. We report a patient with isolated horizontal gaze palsy as a result of a small ischemic lesion of the pontine tegmentum. Observation: A 61-year-old man, with medical history of diabetes mellitus, dyslipidemia and high blood pressure, was hospitalized after 12 hours of transient dizziness and diplopia. On examination, he had conjugate eye deviation to the right side with horizontal gaze paralysis toward controlateral side. Vertical eye movements, convergence and pupillary reflex were preserved with no peripheral facial palsy. Brain MRI revealed a small lesion in the left pontine tegmentum. Patient received aspirin with atorvastatin and the gaze palsy has been disappeared three weeks later. Discussion: Conjugate lateral eye movement paralysis is commonly attributed to lesions of the caudal pons involving the abducens nucleus. horizontal gaze palsy is often associated to an ipsilateral peripheral facial palsy. In our case, the left lateral gaze palsy was isolated. The pontine lesion should be strictly confined the abducens nucleus which is extremely rare. the outcome of eye movement deviation in brainstem lesions is favorable within few weeks. Conclusion: Our case provides evidence that small pontine lesions can damage the abducens nerve nucleus without causing ipsilateral peripheral facial palsy.

Effects of New Bayesian Penalized Likelihood Reconstruction Algorithm on Visualization and Quantification of Upper Abdominal Malignant Tumors in Clinical FDG PET/CT Examinations

PurposeThis study evaluated the effects of new Bayesian penalized likelihood (BPL) reconstruction algorithm on visualization and quantification of upper abdominal malignant tumors in clinical FDG PET/CT examinations, comparing the results to those obtained by an ordered subset expectation maximization (OSEM) reconstruction algorithm. Metabolic tumor volume (MTV) and texture features (TFs), as well as SUV-related metrics, were evaluated to clarify the BPL effects on quantification.Materials and MethodsA total of 153 upper abdominal lesions (82 liver metastatic and 71 pancreatic cancers) were included in this study. FDG PET/CT images were acquired with a GE Discovery 710 scanner equipped with a time-of-flight system. Images were reconstructed using OSEM and BPL (beta 700) algorithms. In 58 lesions <1.5 cm in greatest diameter (small-lesion group), visual image quality of each lesion was evaluated using a four-point scale. SUVmax was obtained for quantitative metrics. Visual scores and SUVmax were compared between OSEM and BPL images. In 95 lesions >2.0 cm in greatest diameter (larger-lesion group), SUVmax, SUVpeak, MTV, and six TFs were compared between OSEM and BPL images. In addition to the size-based analyses, an increase of SUVmax with BPL was evaluated according to the original SUVmax in OSEM images.ResultsIn the small-lesion group, both visual score and SUVmax were significantly higher in the BPL than OSEM images. The increase in visual score was observed in 20 (34%) of all 58 lesions. In the larger-lesion group, no statistical difference was observed in SUVmax, SUVpeak, or MTV between OSEM and BPL images. BPL increased high gray-level zone emphasis and decreased low gray-level zone emphasis among six TFs compared to OSEM with statistical significance. No statistical differences were observed in other TFs. SUVmax-based analysis demonstrated that BPL increased and decreased SUVmax in lesions with low (<5) and high (>10) SUVmax in original OSEM images, respectively.ConclusionThis study demonstrated that BPL improved conspicuity of small or low-count upper abdominal malignant lesions in clinical FDG PET/CT examinations. Only two TFs represented significant differences between OSEM and BPL images of all quantitative metrics in larger lesions.

Magnetic Resonance Imaging (MRI) Evaluation of Sellar Region Tumors with Histopathological Correlation

MRI is a complex, rapidly evolving modality which has assumed an increasingly important role in the diagnosis of Sellar region tumors. It is now the preferred modality for the definitive evaluation and follow-up of the most sellar region tumors. Using different pulse sequence small lesion can be detected even without contrast. Gd-DTPA provides valuable information in MR imaging sellar region tumors, particularly in pre-operative evaluation. This study was conducted to elucidate the accuracy of MRI in pre-operative evaluation of sellar region tumors and its validity by determining sensitivity, specificity, positive and negative predictive value with histopathological correlation. This cross sectional observational study was carried out in the department of radiology and imaging in collaboration with department of Neurosurgery, Dhaka Medical college Hospital, Dhaka during the period of January 2008 to April 2009. MRI of brain was done on 42 patients referred for evaluation of sellar region tumors. The following result and observation were obtained. The age range of the patient was 20 to 80 years. The mean age (HSE) was 34.31(+2.80). Maximum patients were in age group 20-30 years and male-female ratio was 1.8:1. Most sellar region tumor located in the intrasellar with suprasellar extension. Out of 42 patients 37 (88%) patients were truly diagnosed by MRI as sellar region tumors. The sensitivity of MRI to diagnosed macro adenoma was 81.25%, specificity 80.76%, positive predictive value 72.2%, negative predictive value 87.5%, accuracy 80.95%. This study finds that MRI is a valid imaging modality in the diagnosis of pituitary adenoma and sellar region tumor. Bangladesh Med J. 2020 Sept; 49(3) : 1-10

Regulation of stem cell identity by miR-200a during spinal cord regeneration

Axolotls are an important model organism for multiple types of regeneration, including functional spinal cord regeneration. Remarkably, axolotls can repair their spinal cord after a small lesion injury and can also regenerate their entire tail following amputation. Several classical signaling pathways that are used during development are reactivated during regeneration, but how this is regulated remains a mystery. We have previously identified miR-200a as a key factor that promotes successful spinal cord regeneration. Here, using RNA-seq analysis, we discovered that the inhibition of miR-200a results in an upregulation of the classical mesodermal marker brachyury in spinal cord cells after injury. However, these cells still express the neural stem cell marker sox2. In vivo lineage tracing allowed us to determine that these cells can give rise to cells of both the neural and mesoderm lineage. Additionally, we found that miR-200a can directly regulate brachyury via a seed sequence in the 3UTR of the gene. Our data indicate that miR-200a represses mesodermal cell fate after a small lesion injury in the spinal cord when only glial cells and neurons need to be replaced.

Leiomyoma an uncommon benign esophageal tumor

Leiomyoma are rare esophageal masses. Majority remain asymptomatic but may present with dysphagia when more than five centimeters in size. Barium swallow is the initial diagnostic investigation. Small lesion can be observed. Symptomatic and large lesion should undergo prompt surgical enucleation. Here we presented a case of a 35 year old female presenting with progressive dysphagia and gradual weight loss for 5 years along with regurgitation for one year. Clinical examination was unremarkable. Barium study was suggestive of smooth intramural defect with normal mucosa. Computed tomography showed well defined homogenous opacity located intramuraly at the level of junction of middle and distal third of esophagus with normal surrounding structures. Surgical enucleation was done through a right posterolateral thoracotomy. Muscle defect was repaired and checked for possible leaks. Liquid diet was commenced on 5th postoperative day. Patient was discharged on semisolid diet for two weeks with progression to solid meal.

Characterisation of breast lesions: comparison of digital breast tomosynthesis and ultrasonography

Background: The main aim of the study was to characterize breast lesions using digital breast tomosynthesis and ultrasound and compare the detection and characterization of lesions between both the modalities.Methods: This was a cross-sectional, observational study that included 150 women who were screened with mammography followed by digital breast tomosynthesis and ultrasound for breast cancer. Patients approaching willingly for screening as per the inclusion criteria underwent mammography and digital breast tomosynthesis followed by ultrasonography. In lesion showing characteristics of malignancy biopsy correlation was done.Results: About half of the patients had type C tissue composition of the breast (50.67%). Most patients were of age between 35 to 44 years (46%). Malignant lesions were similarly detected by both the modalities. Almost all benign cases were also similarly diagnosed. Sensitivity and specificity of ultrasonography was 94.85% and 92%. Sensitivity and specificity for tomosynthesis was 91.86% and 88.24%. Combined testing showed 100% sensitivity, 97.8% specificity, 98.36% positive predictive value and 100% negative predictive value.Conclusions: Combining use of tomosynthesis and ultrasonography can make it possible to detect any small lesion, malignancy in its earliest stage (in situ) as well as few premalignant conditions like atypical ductal hyperplasia, as in few conditions there is possible sonography negative and mammogram positive calcifications are found.