Background
The terms “renal regenerating nodule” and “nodular compensatory hypertrophy” are used in the literature to describe functioning pseudo-tumors (FPT) in the setting of an extensively scarred kidney. FPTs are usually discovered incidentally during routine renal imaging. Differentiating these FPTs from renal neoplasms is critical but can be challenging in the setting of chronic kidney disease (CKD) given the limitations related to using contrast-based imaging.
Case summaries
We report a pediatric case series of 5 CKD patients, with history of urinary tract infections, in which tumor-like lesions evolved in scarred kidneys and were incidentally discovered on routine renal imaging. These were diagnosed as FPT by utilizing dimercaptosuccinic acid (DMSA) imaging and showed stable size and appearance upon follow-up with ultrasound and MRI.
Conclusion
FPTs can be picked up on routine imaging of pediatric patients with CKD. Although larger cohort studies are needed to confirm these conclusions, our case series supports the evidence that DMSA scan showing uptake at the site of the mass can be a useful tool to suggest the diagnosis of FPTs in children with kidney scarring, and that SPECT DMSA scan adds more precision in picking up and accurately localizing FPTs compared to planar DMSA.
The purpose of this study is to assess the variance and error in nodule diameter measurement associated with variations in nodule-slice position in cross-sectional imaging. A computer program utilizing a standard geometric model was used to simulate theoretical slices through a perfectly spherical nodule of known size, position, and density within a background of "lung" of known fixed density. Assuming a threshold density, partial volume effect of a voxel was simulated using published slice and pixel sensitivity profiles. At a given slice thickness and nodule size, 100 scans were simulated differing only in scan start position, then repeated for multiple node sizes at three simulated slice thicknesses. Diameter was measured using a standard, automated algorithm. The frequency of measured diameters was tabulated; average errors and standard deviations (SD) were calculated. For a representative 5-mm nodule, average measurement error ranged from +10 to −23 % and SD ranged from 0.07 to 0.99 mm at slice thicknesses of 0.75 to 5 mm, respectively. At fixed slice thickness, average error and SD decreased from peak values as nodule size increased. At fixed nodule size, SD increased as slice thickness increased. Average error exhibited dependence on both slice thickness and threshold. Variance and error in nodule diameter measurement associated with nodule-slice position exists due to geometrical limitations. This can lead to false interpretations of nodule growth or stability that could affect clinical management. The variance is most pronounced at higher slice thicknesses and for small nodule sizes. Measurement error is slice thickness and threshold dependent.
Objectives: The differential diagnosis for acute pelvic pain in women includes gynecologic, gastrointestinal, urologic, and vascular diseases. Ultrasound is usually the first-line imaging modality for female pelvic pain due to its accessibility, lack of ionizing radiation and excellent ability to identify female reproductive tract pathology. During pelvic ultrasonography, a less common or unexpected etiology of pelvic pain may be identified, and the clinician should be prepared to recognize these non-gynecologic or less common gynecologic etiologies of pelvic pain. The OBJECTIVES: of this presentation is to describe unexpected and unusual findings that are important for the sonographer and interpreting physician to recognize in their practice. Methods: We reviewed our database for patients that underwent transabdominal and/or endovaginal pelvic ultrasound for evaluation of pelvic pain that revealed findings consistent with non-gynecologic or unusual gynecologic pathologies. We then reviewed these cases for the appearance of ultrasound findings that are diagnostic or highly supportive of specific abnormalities that were not clinically expected, and collected representative images of these abnormalities. We obtained pathologic and imaging correlations for these cases. Results: The unexpected and unusual pathologies found in our database included appendicitis, diverticulitis, colitis, UVJ Calculus, pelvic DVT, mesenteric adenitis, tumors, small bowel obstruction, inflammatory bowel disease, pelvic inflammatory disease, fallopian tube torsion, torsion of pedunculated fibroid, endometriosis, hernia. The sonographic diagnosis was made on the basis of both gray scale and Doppler findings. Conclusions: Ultrasound is ideal for the evaluation of the female reproductive tract and related structures and can also identify non-gynecologic pathologies. We have collected cases with unexpected or unusual ultrasound findings based on the patient's clinical presentation of acute pelvic pain. The sonographer or clinician should be aware of these pathologies and their associated ultrasound findings when performing pelvic ultrasound as they may prove essential for prompt and accurate diagnosis of pelvic pain.
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