Widespread micronodular hepatic metastases of neuroendocrine tumor detected by [68Ga]DOTATATE PET/CT.

Neuroendocrine tumors (NET) encompass a diverse, heterogeneous group of neoplasms that originate from the secretory cells of the neuroendocrine system. These neoplasms typically express the somatostatin receptor (SSTR), which can be targeted by molecular agents for imaging and therapy. This is particularly advantageous for imaging NETs that are indolent, slow-growing, and less well detected by [18F]FDG and for the detection of occult disease not easily identified by anatomic imaging. Herein, we present a case in which [68Ga]DOTATATE PET/CT was used to diagnose the etiology of biochemical recurrence in NET that was not apparent on MRI. The importance of understanding deviations from the normal biodistribution of the radiotracer is emphasized as key in interpreting nuclear medicine studies and establishing the diagnosis. Imaging the SSTR is of particular interest given the recent FDA approval of [68Cu]DOTATATE as a new and possibly more available molecular radiotracer.

"Pseudoseptum" of the uterine cervix on MRI.

PURPOSE: To determine the prevalence of a longitudinal "pseudoseptum" on T2-weighted MR images within the cervices of women who do not have a uterine anomaly. MATERIALS AND METHODS: We reviewed 317 consecutive female pelvic MR examinations performed at a single institution over a four-month period. All examinations included T2-weighted sequences in at least two orthogonal planes. Of the 317 studies, 57 were excluded due to prior radical hysterectomy. Axial and coronal T2-weighted images of the remaining 260 examinations were evaluated for the presence of a longitudinal low T2 signal intensity structure within the endocervical lumen that mimicked the appearance of a septum. Interpretations were performed independently by two MR radiologists and kappa analysis of interobserver agreement was performed. RESULTS: In 50 (19%) of the 260 women, both readers noted the presence of a pseudoseptum on at least one imaging plane. In 162 (62%), neither reader noted a pseudoseptum. Overall, there was 81% agreement between the readers. Kappa analysis yielded a value of 0.55, indicating a moderate degree of interobserver agreement beyond chance. CONCLUSION: A pseudoseptum was depicted in 20% to 30% of women's cervices on T2-weighted imaging. We hypothesize that chance long-axis depiction of the endocervical folds can mimic a cervical septum. The presence of a pseudoseptum on MRI should be considered a normal finding and not a feature of a developmental anomaly of the uterus or cervix.

Metastatic PEComa arising from renal angiomyolipoma: MRI findings.

The perivascular epithelioid cell tumor (PEComa) is a neoplasm composed primarily of HMB-45-positive epithelioid cells with a perivascular distribution. Both benign and malignant PEComas have been reported in diverse anatomic locations. We report the MRI features of a metastatic PEComa to the liver that originated within a renal angiomyolipoma (AML).