A transvaginal grey-scale ultrasound image demonstrating a complex adnexal mass, approximately 6 cm in diameter, located in the juxta-uterine region. The mass is primarily cystic with irregular, thickened walls and heterogeneous internal echogenicity, suggesting the presence of debris, pus, or complex fluid. A characteristic 'cogwheel sign' is visible, represented by thickened endosalpingeal folds that project into the lumen of the dilated fallopian tube, which is a classic sonographic indicator of pyosalpinx. The morphology is tubular and tortuous rather than purely spherical, typical of pelvic inflammatory disease progression. Caliper markers are placed to measure the dimensions of the collection. The surrounding stroma shows increased echogenicity, consistent with inflammatory changes in the adnexa. This diagnostic image illustrates the sonographic features used to differentiate pyosalpinx from other adnexal masses like ovarian cysts or ectopic pregnancies.

This diagnostic ultrasound image demonstrates classic sonographic features of acute salpingitis in two planes. The left panel shows a longitudinal view of a distended fallopian tube appearing as a pear-shaped unilocular mass with low-level internal echogenicity and thickened walls exceeding 5 mm. The right panel displays a transverse section illustrating the 'cogwheel sign,' characterized by multiple small, round, hypoechoic to anechoic structures arranged in a circular or serrated pattern. These protrusions represent cross-sections of thickened, edematous endosalpingeal folds projecting into the tubal lumen. The structures are bounded by incomplete septae and are adjacent to the ovary, which is marked with calipers (Ov-H and Ov-L). These findings are pathognomonic for inflammatory processes of the fallopian tube, such as pelvic inflammatory disease (PID), and help distinguish tubal pathology from primary ovarian masses.

**Modality:** Transvaginal Ultrasound (TVUS), B-mode. **Anatomic Region:** Adnexa / Fallopian tube. **Description:** The image displays a cross-sectional view of a hydrosalpinx, appearing as an elongated, fusiform, and well-circumscribed cystic structure with anechoic internal fluid. A prominent, hyperechoic thin linear band is visible extending into the lumen, representing an incomplete septum or "cogwheel" sign. This feature is a classic sonographic hallmark of a dilated, folded fallopian tube, distinguishing it from an ovarian cyst or para-ovarian mass. **Visual Features:** - **Fluid Collection:** Anechoic, simple fluid without internal debris or vascularity. - **Wall Structure:** Smooth, thin walls with no solid papillary projections or thickened mural nodules. - **Septation:** A pathognomonic incomplete septum (cogwheel sign/waist sign) characteristic of chronic tubal dilatation. - **Measurements:** Orthogonal electronic calipers (marked 1 and 2) are positioned to quantify the maximum diameter of the distended lumen. **Diagnostic Significance:** These features are highly suggestive of hydrosalpinx, typically secondary to pelvic inflammatory disease (PID) or previous tubal pathology, aiding in the differentiation of adnexal masses.

Two-panel transvaginal sonography (TVS) image demonstrating the features of acute salpingitis. Panel A displays a color Doppler ultrasound of a dilated fallopian tube, appearing as a pear-shaped, unilocular adnexal mass. The mass contains low-level echogenic fluid and is characterized by thickened walls (exceeding 5 mm) and multiple incomplete septae extending into the lumen. Panel B shows a power Doppler ultrasound of the same structure, highlighting significant hypervascularity concentrated within the incomplete septae and the thickened tubal wall. These internal projections and the increased vascular signal are classic sonographic indicators of an active inflammatory process, such as acute pelvic inflammatory disease (PID). The morphology of the tube with internal protrusions may also suggest a 'cogwheel sign' when viewed in transverse section, distinguishing acute salpingitis from simple hydrosalpinx.

This diagnostic image is a transvaginal ultrasound (TVUS) in the transverse plane, illustrating a complex adnexal mass consistent with a tubo-ovarian abscess (TOA) secondary to pelvic inflammatory disease (PID). The mass is located in the right adnexa and is characterized by heterogeneous echogenicity, featuring mixed solid (hyperechoic) and cystic/fluid-filled (hypoechoic) components. The internal architecture appears disorganized with thick, irregular walls and ill-defined borders, indicating an inflammatory process. Electronic calipers are seen measuring the lesion, and a black star identifies the adjacent uterus, which appears mildly displaced. The surrounding tissue demonstrates typical sonographic signs of pelvic inflammation, including obscured anatomical planes and potential fluid in the Pouch of Douglas. This image serves as an educational example of advanced pelvic infection, emphasizing the transformation of normal ovarian and tubal anatomy into a unified inflammatory complex. It is intended for medical students and radiology residents to recognize the classic 'ground-glass' or multi-loculated appearance of a pelvic abscess.

**Imaging Modality:** Transvaginal Ultrasound (TVUS) **Anatomical Region:** Left adnexa, coronal plane. **Observed Pathology:** Large, complex tubo-ovarian mass consistent with a Tubo-Ovarian Abscess (TOA). **Characteristic Visual Features:** The image demonstrates a poorly defined, multi-loculated heterogeneous mass involving the left adnexal region. Key features include: * **Echo Texture:** A mixture of hypoechoic and solid-appearing components with internal debris, characteristic of an inflammatory or purulent collection. * **Architecture:** The mass shows thick, irregular walls and internal septations. There is a lack of clear demarcation between the ovary and the fallopian tube, forming a "tubo-ovarian complex." * **Fluid Components:** Presence of low-level internal echoes within cystic areas, suggesting complex fluid or pus. **Key Diagnostic Features:** The primary diagnostic cue is the complete loss of normal adnexal architecture, replaced by a disorganized, heterogeneous mass. The "cogwheel" or "beaded" appearance often associated with salpingitis is obscured by the expansive, organized abscess formation. These sonographic findings are highly suggestive of Pelvic Inflammatory Disease (PID) progressing to a tubo-ovarian abscess.

**Imaging Modality:** Transvaginal Ultrasound (TVUS) **Anatomical Region:** Pelvis (Adnexa) **Observed Pathology:** Tubo-ovarian abscess (TOA) **Characteristic Visual Features:** The image displays a complex, multilocular cystic adnexal mass. Key sonographic features include: * **Wall Morphology:** Distinct, regular thickening of the outer capsule and internal septations (indicated by arrows). * **Internal Content:** The cystic spaces contain low-level internal echogenic debris/fluid, consistent with purulent material or complex fluid. * **Architecture:** The mass lacks solid papillary projections but exhibits a "cogwheel" or "beaded" appearance characteristic of inflammatory adnexal processes involving the fallopian tube and ovary. **Diagnostic Differentiating Features:** The presence of thick, regular walls and septa combined with internal echogenicity helps differentiate this inflammatory complex from simple ovarian cysts or hydrosalpinx. The lack of irregular solid components or high-vascularity nodules (not visible here) helps distinguish it from malignant epithelial ovarian tumors. This presentation is highly suggestive of Pelvic Inflammatory Disease (PID) progressing to a tubo-ovarian abscess.

**Imaging Modality:** Transvaginal Ultrasound (TVUS), B-mode. **Anatomical Region:** Female pelvis, right adnexa. **Observed Pathology:** Hydrosalpinx. **Characteristic Visual Features:** The image demonstrates a prominent, elongated, tubular cystic structure in the adnexa. The mass is primarily anechoic to hypoechoic, indicating fluid collection within a dilated fallopian tube. Distinctive "waist signs" or indentations along the opposite walls of the tube are visible, creating a multiloculated appearance often referred to as a "cogwheel" or "beads-on-a-string" sign in cross-section. **Diagnostic Features:** The structure is separate from the ovary (not visualized in this plane) and lacks the thick, vascularized walls characteristic of a tubo-ovarian abscess or pyosalpinx. Electronic calipers measure the maximal dimensions of the dilated segment (approximately 2.66 cm x 1.76 cm). The presence of incomplete septa (indentations) is a key differentiating feature that distinguishes a dilated fallopian tube from other pelvic cystic adnexal masses such as para-ovarian cysts. **Clinical Context:** Findings are diagnostic of tubal dilation and fluid accumulation, consistent with chronic tubal occlusion and hydrosalpinx in a reproductive-age patient.

This diagnostic image is a transvaginal ultrasound (TVUS) in the transverse plane, illustrating a complex adnexal mass consistent with a tubo-ovarian abscess (TOA) secondary to pelvic inflammatory disease (PID). The mass is located in the right adnexa and is characterized by heterogeneous echogenicity, featuring mixed solid (hyperechoic) and cystic/fluid-filled (hypoechoic) components. The internal architecture appears disorganized with thick, irregular walls and ill-defined borders, indicating an inflammatory process. Electronic calipers are seen measuring the lesion, and a black star identifies the adjacent uterus, which appears mildly displaced. The surrounding tissue demonstrates typical sonographic signs of pelvic inflammation, including obscured anatomical planes and potential fluid in the Pouch of Douglas. This image serves as an educational example of advanced pelvic infection, emphasizing the transformation of normal ovarian and tubal anatomy into a unified inflammatory complex. It is intended for medical students and radiology residents to recognize the classic 'ground-glass' or multi-loculated appearance of a pelvic abscess.

This dual-panel image demonstrates a tubo-ovarian complex involving a left adnexal abscess, illustrated through two diagnostic imaging modalities. Panel (a) is an axial color Doppler transabdominal ultrasound (TSA-US) scan. It reveals a complex cystic mass in the left adnexa characterized by a predominantly anechoic central region, consistent with fluid or purulent material. The color Doppler overlay shows peripheral vascularization (arrow) indicated by red and blue signals around the margins of the mass, reflecting active blood flow in the surrounding inflammatory tissue. Panel (b) is a contrast-enhanced axial CT image of the pelvis. It shows a corresponding left adnexal abscess with a distinctively thickened and hyper-enhancing wall (arrows). The enhancement indicates increased vascularity and inflammation characteristic of an infectious process. These findings are critical for diagnosing pelvic inflammatory disease (PID) and its complications, such as tubo-ovarian abscesses (TOA). This comparison illustrates how ultrasound serves as a primary tool for evaluating vascular compromise and cystic morphology, while CT provides superior detail regarding wall thickening and regional inflammatory extent.

This diagnostic image is a transabdominal ultrasound of the right adnexa in the transverse plane, demonstrating a complex right tubo-ovarian abscess (TOA) measuring approximately 6.2 x 3 x 2.5 cm. The mass exhibits a heterogeneous echotexture with mixed cystic and solid components, characterized by internal low-level echoes and irregular thick walls. The borders of the mass are poorly defined and irregular, blending with adjacent pelvic structures, which is indicative of localized inflammation and pelvic inflammatory disease (PID). Color Doppler overlay reveals internal and peripheral vascularity, showing punctate red and blue signals that represent blood flow within the inflammatory tissue. There is no clear evidence of posterior acoustic shadowing or enhancement. This visual finding is a key diagnostic indicator for advanced pelvic infection and is used in clinical education to distinguish complex adnexal masses from simple ovarian cysts or endometriomas.

This dual-panel image provides a side-by-side comparison of a tubo-ovarian complex (TOC) using two imaging modalities. Panel A is a transvaginal ultrasound (TVUS) showing a large, heterogeneous, complex adnexal mass. The sonogram reveals mixed echogenicity with ill-defined borders, internal septations, and cystic components, indicating the involvement of both the fallopian tube and the ovary in an inflammatory process. Quantitative calipers measure the dimensions of the mass as approximately 35.6 mm x 66.5 mm x 45.4 mm. Panel B is a corresponding laparoscopic photograph of the same case, providing direct visualization of the pelvic cavity. It shows significant erythema and edema of the adnexal structures, with thick inflammatory adhesions and a whitish-yellow purulent-appearing exudate characteristic of a tubo-ovarian abscess. The laparoscopic view clarifies the anatomical distortion and tissue friability suggested by the ultrasound. This comparison illustrates the diagnostic pathway for pelvic inflammatory disease (PID) progressing to abscess formation, highlighting the correlation between sonographic heterogeneity and gross surgical inflammation.