Imaging of pulmonary infections encountered in the emergency department in post-COVID 19 era- common, rare and exotic. Bacterial and viral.

Pulmonary infections contribute substantially to emergency department (ED) visits, posing a considerable health burden. Lower respiratory tract infections are prevalent, particularly among the elderly, constituting a significant percentage of infectious disease-related ED visits. Timely recognition and treatment are crucial to mitigate morbidity and mortality. Imaging studies, primarily chest radiographs and less frequently CT chests, play a pivotal role in diagnosis. This article aims to elucidate the imaging patterns of both common and rare pulmonary infections (bacterial and viral) in the post COVID-19 era, emphasizing the importance of recognizing distinct radiological manifestations. The integration of clinical and microbiological evidence aids in achieving accurate diagnoses, and guiding optimal therapeutic interventions. Despite potential overlapping manifestations, a nuanced understanding of radiological patterns, coupled with comprehensive clinical and microbiological information, enhances diagnostic precision in majority cases.

CT guided injection of 99mTc-MAA for lung nodule localization prior to VATS.

AIM: CT guided technetium99m-macroaggregated albumin (99mTc-MAA) injection for lung nodule localization prior to video-assisted thoracoscopic surgery (VATS) is employed at our institution for more than a decade. We retrospectively studied the success rate, factors that affect outcomes, and complications of this procedure. MATERIALS AND METHODS: 147 patients with 164 nodules underwent this procedure before VATS. Imaging and procedure characteristics, complications of the procedure, successful intra-operative localization and wedge resection, if there was conversion of primary VATS to open thoracotomy and if so the reason, and histopathological diagnosis for each nodule were reviewed by two radiologists in consensus. In case of unsuccessful wedge resection, reasons for failure were derived from electronic medical record. The impact of nodule and procedure characteristics on successful intra-operative localization was assessed. RESULTS: Excluding 9 nodules with unsuccessful localization due to non-procedure related reasons, the CT guided procedure was successful in 96.1% for intraoperative localization (149/155). Pleural leak of the radiotracer, split injection within the lobe, injection into a wrong nodule and gamma probe malfunction were primary reasons for failure. Nodule size, depth from pleura, and time between radiotracer injection and surgical incision did not impact success of the procedure. Among the 6 cases with procedure related failure, only 1 required conversion to open thoracotomy. CONCLUSION: CT guided 99mTc-MAA injection for intra-operative lung nodule localization is a feasible procedure with a high success rate and low complication rate. Attention to technique can potentially avoid procedure failure.

Enhancement pattern of differentiated and undifferentiated gastric carcinoma on multiphasic contrast-enhanced computed tomography.

PURPOSE: To study the enhancement pattern of differentiated and undifferentiated gastric carcinoma on multiphasic contrast-enhanced computed tomography (CT). MATERIAL AND METHODS: Seventy patients with biopsy-proven gastric cancer underwent multiphasic contrast-enhanced CT. The CT protocol include plain, arterial, portal venous, and hepatic venous phase. Tumour size, location, peak-enhancement characteristics, and staging were evaluated. RESULTS: The peak-enhancement type was 'arterial' in 20 out of 28 within the differentiated-type GCAs and 'portalvenous' in 37 out of 42 within the undifferentiated-type GCAs (c2 statistic with Yates correction = 23.3981, p < 0.00001). The maximum attenuation value was statistically significant for the arterial phase between differentiated and undifferentiated GCAs (p < 0.05). CONCLUSIONS: Assessing peak-enhancement in a multiphasic CT can help identify the histological subcategory of gastric carcinomas that has prognostic significance. Arterial phase peak-enhancement is frequently seen in differentiated carcinomas whereas venous phase peak-enhancement is seen in undifferentiated carcinomas.

Study of Programmed Death Ligand 1 and EGFR/HER2 Expression in Non-Small-Cell Lung Carcinoma With a Clinicopathological Spectrum.

Non-small-cell lung carcinoma (NSCLC) is a disease characterized by the upregulation of programmed death ligand 1 (PD-L1) along with alterations in epidermal growth factor receptor (EGFR) and HER2-neu (HER2) amplification in addition to EGFR mutation. In the present study, the expression of PD-L1 and EGFR and HER2-neu in NSCLC was studied and their expression in relation to various clinicopathological parameters was analysed. We studied 49 core biopsy specimens of NSCLC for PD-L1, EGFR and HER2-neu expressions using immunohistochemistry. Scoring was based on the intensity and percentage of tumour cells expressing the immunomarkers. PD-L1, EGFR and HER2-neu expression was seen in 20.4%, 32.7% and 14.2% of NSCLC, respectively. The analysis showed no significant difference in PD-L1 expression in relation to any clinicopathological parameters. Low or negative EGFR expression was significantly associated with positive lymph node status (P=0.04). HER2-neu expression showed a significant difference in relation to tumour histology (adenocarcinoma; P=0.01). Also, there was no difference noted with PD-L1 expression in relation to EGFR and HER2-neu expression. As our study has a small number of cases, the validation of the predictive and prognostic value of these markers in lung cancer patients requires further studies.

Papillary Urothelial Carcinoma of Urinary Bladder Identified on 18F-Fluciclovine PET/CT.

ABSTRACT: 18F-fluciclovine is a radiolabeled synthetic amino acid recently approved by the Food and Drug Administration for evaluating recurrent prostate cancer. Upregulated amino acid transporters in prostate cancer cells result in elevated radiotracer uptake in sites of tumor recurrence. However, 18F-fluciclovine is not specific for prostate cancer. Nonprostatic malignancies and benign conditions can also demonstrate uptake. This information combined with the knowledge about common patterns of prostate cancer recurrence helps guide appropriate management. We present an 87-year-old man with biochemical recurrence for prostate cancer but found to have a urinary bladder wall mass on 18F-fluciclovine PET/CT with moderate avidity. Biopsy revealed papillary urothelial carcinoma.

"Perifollicular rim sign" in an enlarged ovary-an additional non-contrast CT finding in ovarian torsion.

PURPOSE: To look for the presence of "perifollicular rim sign" on non-contrast CT in surgically proven cases of ovarian or adnexal torsion. METHODS: A retrospective analysis of abdominopelvic non-contrast CT examinations in surgically proven cases of ovarian or adnexal torsion was conducted seeking the presence of "perifollicular rim sign" in torsed ovaries. "Perifollicular rim sign" was defined as a complete ring of perifollicular hyperdensity around ovarian follicles with an attenuation value of > 50 HU and thickness > 1-2 mm. A positive sign was equated to the presence of perifollicular hemorrhage. Pre-operative non-contrast CT was available in 7 out of the 39 ovarian or adnexal torsions included in our study. RESULTS: "Perifollicular rim sign" was present in 5 out of the 7 ovarian torsions on pre-operative non-contrast CT. MRI correlation was available in one patient. Ovarian enlargement (>4 cm) was present in all 7 cases. CONCLUSION: In an appropriate clinical setting, presence of "perifollicular rim sign" in an enlarged ovary on non-contrast CT examination can be considered a useful additional sign for ovarian torsion.

Symptomatic Oppenheimer ossicle: a rare mimic of pars interarticularis fracture.

We report a case of symptomatic Oppenheimer ossicle in an 18-year-old male who presented with back pain. L5 pars interarticularis defect was suspected on initial lumbar spine radiographs. A subsequent technetium99m-methylene diphosphonate (Tc99m-MDP) bone scintigraphy with single-photon emission computed tomography/computed tomography (SPECT/CT) revealed focal radiotracer uptake in an Oppenheimer ossicle in L2 vertebra. CT was negative for pars defect. Oppenheimer ossicle is a developmental variant resulting from an unfused accessory ossification center at the tip of the articular process. It is important to recognize this entity as a rare cause of low back pain. Focal tracer uptake can mimic changes from pars interarticularis defect on planar and SPECT images. SPECT/CT helps to resolve both entities. To our knowledge, this is also the first report in English literature describing a symptomatic Oppenheimer ossicle on a bone scan.

Chronic sphenoid sinusitis revisited: comparison of multidetector axial sections, multiplanar reconstructions, and virtual sinoscopy with endoscopic sinus surgery.

OBJECTIVES: To assess the role of multidetector computed tomography (CT) and CT virtual sinoscopy in the evaluation of chronic sphenoid sinusitis and to compare the imaging findings with functional endoscopic sinus surgery. DESIGN: Prospective study. SETTING: Tertiary care teaching hospital. PATIENTS: Thirty patients with chronic sphenoid sinusitis referred for preoperative CT. INTERVENTIONS: Thin-section helical axial CT was performed using a multidetector CT scanner with multiplanar reformation (MPR) and volume-rendered or virtual sinoscopy images. Sixty sinuses were divided into quadrants for analysis. Extrasinus extension was labeled as the "fifth quadrant." MAIN OUTCOME MEASURES: Imaging findings were compared with those of functional endoscopic sinus surgery, and accuracy of the imaging modality was determined. RESULTS: Multidetector CT (axial CT and MPR) was found to be 100% sensitive, specific, and accurate in the evaluation of extent of sinusitis, status of the sinus septum, integrity of the optic nerve canal in relation to the sinus, and type of sinus pneumatization. Axial CT and MPR images showed sensitivity of 98% and specificity of 92% compared with functional endoscopic sinus surgery in evaluating the ostia. Regarding carotid canal integrity, axial CT and MPRs were 100% sensitive and 98% specific. Virtual sinoscopy showed sensitivity and specificity of 67% and 92%, respectively, for the 22 ostia that could be visualized and evaluated using this modality. CONCLUSIONS: Axial multidetector CT with secondary MPRs provide the necessary preoperative information regarding extent of disease and sphenoid sinus anatomy. Virtual sinoscopy is a navigational aid, an adjunct to endoscopy, and an educational tool for surgeons-in-training.