Manual for abdominal ultrasound in cancer screening and health checkups, revised edition (2021)

Introduction

This manual is a revised version of the first edition [1,2,3] published jointly by the Japanese Society of Gastrointestinal Cancer Screening (JSGCS), the Japan Society of Ultrasonics in Medicine (JSUM), and Japan Society of Ningen Dock (JSND) in 2014.

Abdominal ultrasonography is distinct in that it is used to examine many organs, and it is applicable various kinds of disease including malignant neoplasm. Moreover, a procedure for describing examination findings had not been standardized. Therefore, its objective accuracy and efficacy as a screening modality could not be evaluated. In addition, there were no clear rules regarding examination procedures at any of the societies. Against this backdrop, the Guideline for Abdominal Ultrasound Cancer Screening [4, 5]—which was comprised of practice standards aimed at improving the quality of abdominal ultrasound cancer screening, and assessment criteria to allow for accurate assessment as a cancer screening modality—was published in 2011, led by the JSGCS Ultrasonic Screening Committee (former Ultrasonography Working Group). The Abdominal Ultrasound Screening Assessment Manual was subsequently created through a joint effort by the above-mentioned three societies by partially revising the Guideline and adding items and assessments. The aim was to improve the quality of and homogenize abdominal ultrasound screening, standardize examination results, and evaluate accuracy and efficacy through the widespread adoption of the Guideline by creating a manual shared by the three societies.

This revision had been planned to take place about 5 years after the original publication. The manual was revised by working groups at each of the three societies, with the additional participation of the Japanese Society of Sonographers (JSS), Japan Society of Health Evaluation and Promotion (JSHEP), and Japanese Association for Cancer Detection and Diagnosis (JACDD) as observer societies, based on current experience. The manual was created with the following structure: practice standards and specific ultrasound findings and categories, tables with ultrasound findings in Report Forms and assessments presented 1:1 and cautionary notes, and representative ultrasound images of the respective findings.

It is a well-known fact that the accuracy of ultrasonography differs depending on the status of the device, examiner, and examinee. In modern medicine, standards are required in terms of ergonomics and device conditions (including periodic inspections) to improve examination quality; the practice standards in this manual were revised based on the guidelines of each society as well as other sources. Although evidence is lacking in some areas and they are not required, we hope that institutions will refer to this manual as a rule of thumb for the current examination environment.

The biggest shortcoming of ultrasonography is a lack of objectivity, which it true of not only ultrasound images but also ultrasound findings and assessments. When we consider such factors as examinee/examiner transfers and diversification of secondary examination facilities, we predict a dramatic improvement in objectivity with the permeation of this manual, and we look forward to its widespread adoption going forward.

Practice standards

• (1) Before beginning an examination

  In terms of screening techniques performed primarily on people without symptoms, we have the "medical checkup," which is used to check and learn the level of an individual's health or check for risk of future disease, and "screening," the purpose of which is to check for the presence or absence of a specific disease. It should be noted that there are examinations where the two cannot be clearly distinguished based on the examination items [6]. Cancer screening, which is a typical screening, has two types: a population-based type carried out by municipalities and an opportunistic type carried out in other situations. In the case of population-based cancer screening, the Japanese government has proposed screening for five major cancers by modalities confirmed to lower the mortality rate. In addition to opportunistic cancer screening for hepatic cancer, renal cancer, and other cancers, this Abdominal Ultrasound Screening Assessment Manual also covers "screenings" to check for the presence or absence of disorders such as gallstones, as well as "medical checkups" to check for future disease risk such as hepatic steatosis and arteriosclerosis.

  There are merits and demerits with any cancer screening, not just ultrasonography, but the merits must outweigh the demerits. Therefore, the examiner needs to understand the merits and demerits of cancer screening and improve the quality of the screening, and the examiner must obtain proper informed consent from the examinee. It is also important to understand that there are two distinct reasons for performing a thorough examination in response to an abnormal finding detected by screening: one is to make a definitive diagnosis of cancer and the other is to rule out suspected cancer.

  Merits

  • Early treatment based on early detection of cancer is possible.

  • Psychological sense of relief when no abnormalities are found.

  Demerits

  • Possibility of false-negative tests (ultrasonography does not detect 100% of cancers).

  • Possibility of false-positive tests (as a result, there is a possibility of examinee complications associated with unnecessary invasive procedures and examinations, and being subjected to psychological and economic strain).

  • Possibility of overdiagnosis (detection of cancer that does not affect the vital prognosis).

• (2) Target organs

  • The target organs covered in this Manual are the liver, biliary tract, pancreas, spleen, kidneys, and abdominal aorta.

  • Tell the examinee the target organs in advance, and explain that there may be some cases and sites where each organ may be difficult to observe.

  • The adrenal gland and lower abdominal region (e.g., bladder, uterus, ovaries, and prostate) are not formally regarded as target organs, but any findings observed during the scanning process should be recorded. In addition, in cases where a target organ will be added with a voluntary contract with the client, clearly communicate the details of the examination to the examinee.

• (3) Examination environment

  • [1] Diagnostic unit

    • Use a convex probe with a frequency of 3.5-7.0 MHz.

    • Add other probes such as a high-frequency probe (7.5 MHz or higher), linear probe, or microconvex probe as necessary according to the examinee's situation.

    • Use of a unit capable of tissue harmonic imaging and color Doppler is recommended.

    • Periodically perform appropriate maintenance/management of the diagnostic unit, and avoid using a unit beyond its service life (normally 7 years).

  • [2] Operators

    A JSGCS gastrointestinal cancer screening general certified physician or gastrointestinal cancer screening certified physician (hepatobiliary system and pancreas), JSUM specialist or technician with an ultrasonographer qualification in the medical checkup domain or gastrointestinal domain certified by JSUM, Board Certified Physician of JSND, Health Evaluation and Promotion Specialist of JSHEP/JSND, Japan Radiological Society (JRS) radiology specialist, or Japanese Society of Laboratory Medicine (JSLM) clinical laboratory test specialist should be in charge of the examination.

  • [3] Advanced preparation

    • Examinees with an examination scheduled for the morning should not eat solid foods or dairy products after 10 p.m. the night before.

    • Examinees with an examination scheduled for the afternoon should not eat solid foods or dairy products within 6 h before the examination.

    • Drinking liquids (e.g., cold/hot water) to prevent dehydration is allowed up to about 200 ml per time up to 2 h before the examination.

    • In cases where a gastrointestinal tract examination will be performed the same day, perform ultrasonography first, with the exception of upper endoscopy using carbon dioxide [7].

  • [4] Peripheral facilities

    • A proper examination environment is said to not only lessen examiner fatigue but also prevent misdiagnosis, making it an important factor.

    • In addition to a private room to protect the examinee's privacy or equivalent examination room, there is an ergonomically recommended environment that encompasses everything including the heights of the examining table, chair, and monitor; therefore, one should aim to perform examinations under the correct environment (Refer to "Proposal from The Japan Society of Ultrasonics in Medicine for ultrasonographers to work safely, comfortably, and healthily: Equipment and work environment to prevent work-related musculoskeletal disorders and eye disorders" [8]).

  • [5] Precautions during epidemics

    • The COVID-19 pandemic completely changed how screenings are performed. Examiners will need to familiarize themselves with ultrasonography-related precautions during epidemics in preparation for new infectious diseases in the future based on this experience.

    • Ultrasonography has distinct examination procedures, sanitization procedures, and so forth that differ from those of other medical care.

    • Take into account ultrasound screening methods during epidemics by referring to such sources as the Ultrasound Equipment and Safety Committee's "Recommendations and resources related to handling and safety of ultrasonic diagnostic equipment" [9,10,11] published on the JSUM website.

  • [6] Recording and scanning procedures

    • There are a variety of image recording/storage methods depending on the institution, such as storage using a thermal printer, storage as DICOM data, and video storage on videotape/DVD. However, storage of DICOM data on electronic media is recommended from the viewpoint of secondary image interpretation and sending referral attachments to facilities for thorough examination.

    • Perform measurements with the image adequately enlarged on the monitor, and denote measurements in millimeters, rounding off to the nearest integer. (However, evaluation of an entire organ can be denoted in centimeters.)

    • For Category 3 or severer lesions and focal lesions, always record images from multiple directions, and also record and save the maximum diameter/scan site at the same time.

    • With respect to the scanning procedure, carefully and thoroughly observing the entirety of each organ as a basic ultrasound scan, and properly evaluating not only focal lesions but also diffuse lesions throughout an entire organ, are fundamental.

    • With respect to standards for sections to store during examinations, there is no nationwide uniform method. However, fundamental sections should be established to properly deal with situations, such as demonstration of the examination region, quality control, double interpretation, comparison of changes over time, referral to other institutions, education, and transfer of examiners/examinees.

    • With respect to the position of the examinee, scans are almost always performed with the examinee in the supine position, but since the visualization capability of ultrasonography changes with a change of position, appropriate position changes (e.g., right and left half side-lying position, right and left lateral position, semi-sitting position, and sitting position) should be utilized in cases where observation in the supine position is insufficient.

    • The time required for examinations will differ depending on the examination environment, but about 5-6 people without findings can be screened per hour (Ample time should be allocated as examination duration correlates with examination accuracy and the ability of the examiner.)

    • Twenty-five recommended sections to record [12] and images by position change are presented here (Fig. 1, Fig. 2).

  • [7] Examination results/image interpretation/ultrasound image findings/assessments/post-examination management

    • For examination results, record the results using the categories described later together with a record of the ultrasonography findings (Table 1-1).

    • With respect to examinations performed by a technician, a JSGCS gastrointestinal cancer screening general certified physician or gastrointestinal cancer screening certified physician (hepatobiliary system and pancreatic), JSUM specialist, Board Certified Physician of JSND, Health Evaluation and Promotion Specialist of JSHEP/JSND, JRS radiology specialist, or JSLM clinical laboratory test specialist should make the final interpretation/diagnosis and complete a report.

Fig. 1

Twenty-five recommended sections to record

Fig. 2

Images by position change

Table 1 Categories

• (4) Examination interval

  Recommend annual screening even if there are no abnormal findings.

• (5) Selection of institution for thorough examination

  • Referral to an institution for thorough examination is an important factor for examinees; therefore, examinees should be instructed to visit and referred to an appropriate medical institution according to the screening results. In addition, it is important to maintain a line of communication with the receiving institution, so that requests can be made for feedback on the results of thorough examinations as it will serve as important information at annual screenings.

  • When writing a referral, include not only the test results but also clearly state the details of the request for thorough examination, and also attach images from the entire examination (DICOM digital images are recommended).

• (6) Quality control

  • Controlling the screening process as a whole so that it is always properly performed is important in order for ultrasound screening to continue to be effective as a cancer screening modality going forward. In addition to internal quality control, it is recommended that the process also undergoes periodic outside evaluation.

  • In addition to control of the examination environment including the diagnostic unit, quality control includes but is not limited to tabulation and management of examination results (e.g., percentage of examinees who required thorough examination, percentage of examinees who underwent thorough examination by category assessment, and cancer detection rate), ascertainment and tabulation of post-examination guidance (e.g., ascertainment and tracking of examinees who did and did not undergo thorough examination, screening recommendation, and ascertainment of screening sensitivity/specificity), and cooperation with and registration in nationwide tabulation.

• (7) Education

  • Continued education for physicians, clinical technologists, radiology technicians, nurses, and others involved in screening is important to update knowledge and improve skills.

  • In addition to holding in-house review meetings to iron out differences of opinion and help improve diagnostic accuracy, an institution should create a system that allows team members to periodically participate in conferences, workshops, and training courses. Furthermore, providing support and cooperation aimed at team members acquiring JSGCS, JSUM, JSND, JSLM, and other qualifications is also important.

• (8) Recommended images to record (Figs. 1, 2).

Categories and assessments

• (1) Ultrasound imaging findings

  • Operators should consider in detail to which ultrasound imaging finding item in the Manual the abnormal findings noted in observations of the liver, biliary tract, pancreas, spleen, kidneys, abdominal aorta, and other target organs correspond and select the applicable item.

  • Although observation of organs other than the target organs is not essential, describe any findings that are noted.

  • If an organ cannot be visualized at all, it should be assessed as "Unable to visualize." If part of an organ cannot be visualized, it should be assessed as "Poorly visualized" and regarded as equivalent to "Difficult to visualize" and "Inadequately visualized," and cases where the border is indistinct after partial resection, etc., should be included in this category; clearly describe poorly visualized sites and use findings from sites that could be visualized.

• (2) (Categories (Tables 1, 2)

  • The cancer-related category, ultrasound findings (described in Report Form), and assessment are determined in accordance with the ultrasound imaging findings selected.

  • Categories are criteria for cancer detection and also summaries of findings noted during ultrasonography.

  • For each organ, the highest category should be recorded as the category for the organ. However, in cases where the highest category and highest assessment differ, both should be recorded (e.g., Category 2/Assessment D2, Category 3/Assessment C).

  • For a lesion that can be compared with a past image, record comments on any chronological changes.

  • If a lesion has findings corresponding to Assessment D2 or higher on ultrasound images but has been deemed to be benign as a result of thorough examination, the relevant category is indicated with an apostrophe [e.g., 0', 2', 3', 4'], and the assessment is C. (Note that the high-risk group is not included in this category.) (Fig. 3)

Table 2 Category table (example)

Fig. 3

Commonly focal spared area in fatty liver. If it is an irregular hypoechoic area in a commonly focal spared area without a disturbed speckle pattern, and no deviation in blood flow is detected on color Doppler, it is not considered a solid lesion (Figs. Liver-6 to 8)

• (3) Ultrasound findings (described in Report Form)

  It consists of simplified terms for notification of ultrasound imaging findings to examinees. Ultrasound findings are described in the Report Form. Categories 4 and 5 are described as “Tumor” and Category 3 focal lesions as “Mass,” including suspected ones.

• (4) Assessment (Table 3)

Table 3 Assessment

As a rule, the final assessment is determined by the physician in charge of assessment in accordance with the Manual based on abnormal findings on ultrasound images. However, the physician in charge of assessment can change the assessment as necessary based on test results other than ultrasonography and comparison with previous findings.

Notes

• P: Panic finding, Promptly report Category 5 lesions to the physician in charge of assessment.

• Promptly report it to the physician in charge of assessment in the case of findings indicative of transition to an emergency situation such as biliary stone.

• For Assessment C, the term "Follow-up observation needed" had been used until now, but the timing of follow-up observation was unclear; therefore, "Reexamination needed" will be used instead going forward to standardize the terminology at institutions, and the specific timing will be entered.

• The reexamination timing selected was 3/6/12 months, but it can be changed at the direction of the physician in charge of assessment.

• Reexaminations will be performed at a medical institution as necessary, but in the case of the 12-month reexamination, the examinee should be strongly recommended to undergo screening the following year.

• In the case of Category 2', 3', or 4' with Assessment C, ultrasonography at the annual screening 12 months later may be used as a substitute for reexamination.

• If "Reexamination needed" is selected, the examinee should be given specific instructions regarding the institution to visit for reexamination.

• If "Thorough examination needed" is selected, the examinee should be given specific instructions regarding the institution to visit for thorough examination and examination procedures, etc.

• When the examinee undergoes reexamination (e.g., during dietary therapy for hepatic steatosis, or main pancreatic duct dilatation/pancreatic cyst) either in-house or at another institution (every 3/6/12 months), the assessment should be C, not E.

• Assessment C or E may be selected if the examinee has undergone thorough examination at another medical institution and continues to be followed up by the institution. However, for an examinee in the group at high risk for cancer, Assessment D2 may be selected after hearing the details of examinations performed at the medical institution.

• A Category 3 lesion may be assessed as C if there are no chronological changes compared with at least the past 2 results.

• Assessment D2 may be selected as necessary if the diameter of the focal lesion or lumen definitely increases compared to the previous result.

• If organ atrophy is found, refer to the past medical history, history of present illness, or treatment history when making the assessment.

• In the case of total resection, partial resection, or detection of treatment scar, refer to the past medical history or history of present illness when making the assessment.

• Make use of color Doppler ultrasound as appropriate to aid assessment.

• Assessment D2 may be selected as necessary for a focal lesion in the liver if chronic hepatic disease is suspected based on clinical biochemistry data such as infection with HBV or HCV or presence of thrombocytopenia (<15,000/μL).

• Assessment D2 may be selected if a biliary tract enzyme abnormality is found in a case with a poorly visualized extrahepatic bile duct.

• (5) Category and assessment table for each organ (Tables 4, 5, 6, 7, 8, 9, 10)

Table 4 Liver

Fig. 4

Post-local treatment. Left: post-radiofrequency ablation; right: post-hepatic arterial embolization. Category 3, Assessment C  Please align the size of images(8,13-16, 21-26, 28-30, 32-34)

Fig. 5

Diffuse lesion. Any one of bright liver, liver-kidney (spleen) contrast, deep attenuation, or intrahepatic vascular blurring is present. Left: liver–kidney contrast; right: liver–spleen contrast. Category 2, Assessment C

Fig. 6

Diffuse lesion. Commonly focal spared area in fatty liver (Around the gallbladder: Cystic vein reflux region). Left: B-mode, Right: Power Doppler. Category 2, Assessment C

Fig. 7

Diffuse lesion. Commonly focal spared area in fatty liver (Right gastric vein ectopic reflux region). Left: Dorsal S4, Right: Dorsal S2. Category 2, Assessment C

Fig. 8

Diffuse lesion. Commonly focal spared area in fatty liver (Frontal S4 immediately below the liver surface: Sappey's venous reflux region). Category 2, Assessment C

Fig. 9

Diffuse lesion. Dull hepatic edge/rough parenchymal echo pattern or nodular rugged liver surface is present (either one) (only dull hepatic margin is noted). Left: right intercostal scan (right hepatic lobe) with convex probe; right: midline vertical scan (left hepatic lobe) with high-frequency probe. Category 3, Assessment C

Fig. 10

Diffuse lesion. Dull hepatic edge/rough parenchymal echo pattern or nodular rugged liver surface is present (either one). Bamboo blind sign (include in rough echo pattern). Left: right intercostal scan with convex probe; right: right intercostal scan with high-frequency probe. Category 3, Assessment C

Fig. 11

Diffuse lesion. Dull hepatic edge/rough parenchymal echo pattern and nodular rugged liver surface are present (all) (flag sign). Left: midline vertical scan with convex probe, right: midline vertical scan with high-frequency probe. Category 3, Assessment D2

Fig. 12

Diffuse lesion. Dull hepatic edge/rough parenchymal echo pattern and nodular rugged liver surface are present (all). Left: right intercostal scan (right hepatic lobe), right: midline vertical scan (left hepatic lobe). Category 3, Assessment D2

Fig. 13

Diffuse lesion. Dull hepatic edge/rough parenchymal echo pattern and nodular rugged liver surface are present (all) (high-frequency probe). Category 3, Assessment D2

Fig. 14

Solid lesion. A solid hepatic lesion is present (maximum diameter < 15 mm). Category 3, Assessment C

Fig. 15

Solid lesion. Solid lesion with involvement of Category 3 diffuse lesion. Category 4, Assessment D2

Fig. 16

Solid lesion. A solid lesion is present. Maximum diameter ≥ 15 mm. Category 4, Assessment D2

Fig. 17

Hepatic neoplastic lesion. Marginal strong echo. Left: Convex probe, Right: High-frequency probe. Category 2, Assessment C

Fig. 18

Hepatic neoplastic lesion. Chameleon sign/wax and wane sign (change in internal echo detected). Category 2, Assessment C

Fig. 19

Hepatic neoplastic lesion. Disappearing sign. Left: Before compression, Right: After compression. Category 2, Assessment C

Fig. 20

Hepatic neoplastic lesion. Sludge worm sign. Left: High-frequency probe, Right: Zoom image. Category 2, Assessment C

Fig. 21

Hepatic neoplastic lesion. Peripheral hypoechoic zone/posterior echo enhancement. Category 4, Assessment D2

Fig. 22

Hepatic neoplastic lesion. Multiple neoplastic lesions. Category 4, Assessment D2

Fig. 23

Hepatic neoplastic lesion. Distal bile duct dilatation. Category 4, Assessment D2

Fig. 24

Hepatic neoplastic lesion. Mosaic pattern. Category 5, Assessment D1

Fig. 25

Hepatic neoplastic lesion. Bright loop appearance. Category 5, Assessment D1

Fig. 26

Hepatic neoplastic lesion. Hump sign. Category 5, Assessment D1

Fig. 27

Hepatic neoplastic lesion. Cluster sign. Left: Convex probe, Right: High-frequency probe. Category 5, Assessment D1

Fig. 28

Hepatic neoplastic lesion. Bull's eye pattern (target sign). Category 5, Assessment D1

Fig. 29

Hepatic neoplastic lesion. Intraportal tumor embolism is present. Category 5, Assessment D1

Fig. 30

Cystic lesion. Solid component (intracystic nodules/wall thickening/septal thickening) is present. Intracystic nodules are present. Category 4, Assessment D2

Fig. 31

Cystic lesion. Solid component (intracystic nodules/wall thickening/septal thickening) and change in internal fluid (e.g., internal echogenic spots) are present. Left: cyst wall thickening; right: echogenic spots in internal fluid. Category 4, Assessment D2

Fig. 32

Cystic lesion. Distal bile duct dilatation. Category 3, Assessment D2

Fig. 33

Other findings. Calcified opacity. Comet-like echo. Category 2, Assessment C

Fig. 34

Other findings. Pneumobilia. Category 2, Assessment B

Fig. 35

Other findings. Vascular abnormality (portal-venous shunt). Left: B-mode; right: color Doppler. Category 2, Assessment D2

Table 5 Gallbladder/extrahepatic bile duct

Fig. 36

Measurement of bile duct diameter

Fig. 37

The gallbladder wall is inevaluable (the wall is inevaluable due to being filled with stones). Category 3, Assessment D2

Fig. 38

The gallbladder wall is inevaluable (the wall is inevaluable due to food intake). Category 3, Assessment D2

Fig. 39

Gallbladder distension. Maximum short diameter ≥ 36 mm. Category 3, Assessment D2

Fig. 40

Wall thickening. Diffuse wall thickening (without small cystic structure or comet-like echo). Category 3, Assessment D2

Fig. 41

Wall thickening. Diffuse wall thickening (with cholecystolithiasis and small cystic structure or comet-like echo). Category 2, Assessment C

Fig. 42

Wall thickening. Diffuse wall thickening (with irregularity of the layered structure of the wall and disruption of the outermost hyperechoic layer). Category 4, Assessment D2

Fig. 43

Wall thickening. Localized wall thickening (without small cystic structure or comet-like echo). Left: convex probe; right: high-frequency probe. Category 4, Assessment D2

Fig. 44

Wall thickening. Localized wall thickening (mimicking debris echo without small cystic structure or comet-like echo). Left: long-axis view; right: short-axis view. Category 4, Assessment D2

Fig. 45

Wall thickening. Localized wall thickening (papillary without small cystic structure or comet-like echo). Category 4, Assessment D2

Fig. 46

Wall thickening. Localized wall thickening (with comet-like echo). Category 2, Assessment C

Fig. 47

Protruded or mass lesion (polyp). Pedunculated (maximum diameter < 5 mm). Category 2, Assessment B

Fig. 48

Protruded or mass lesion (polyp). Pedunculated [maximum diameter ≥ 5 mm, < 10 mm (mulberry-like)]. Category 2, Assessment B

Fig. 49

Protruded or mass lesion (polyp). Pedunculated [maximum diameter ≥ 5 mm, < 10 mm (with hyperechoic spot)]. Category 2, Assessment B

Fig. 50

Protruded or mass lesion (polyp). Pedunculated (maximum diameter ≥ 10 mm). Category 4, Assessment D2

Fig. 51

Protruded or mass lesion (polyp). Sessile (non-pedunculated) (without tear of the layered structure of the attached wall). Category 4, Assessment D2

Fig. 52

Protruded or mass lesion (polyp). Sessile (non-pedunculated) (with small cystic structures). Left: convex probe; right: high-frequency probe. Category 2, Assessment C

Fig. 53

Protruded or mass lesion (polyp). Sessile (broad-based) (with tear of the layered structure of the attached wall). Category 5, Assessment D1

Fig. 54

Other findings. Stone image (strong echo without wall thickening). Category 2, Assessment C

Fig. 55

Other findings. Pneumobilia (movable linear strong echo with position change). Category 2, Assessment C

Fig. 56

Other findings. Debris echo (gallbladder). Category 3, Assessment D2

Fig. 57

Other findings. Debris echo (mass lesion with the irregular outermost hyperechoic layer of the attached wall of the extrahepatic bile duct) (left: gallbladder, right: extrahepatic bile duct). Gallbladder is Category 3 and Assessment D2, but extrahepatic bile duct is Category 5 and Assessment D1

Fig. 58

Extrahepatic bile duct. Morphological abnormality. (Dilatation of the perihilar extrahepatic bile duct is present, but abnormal findings up to the distal bile duct near the papillary edge are not present.) Left: Perihilar extrahepatic bile duct, Right: Distal extrahepatic bile duct. Category 2, Assessment C

Fig. 59

Extrahepatic bile duct. Morphological abnormality. Extrahepatic bile duct dilatation with cystic shape. Category 4, Assessment D2

Fig. 60

Extrahepatic bile duct. Morphological abnormality. Extrahepatic bile duct dilatation with fusiform shape. Category 4, Assessment D2

Fig. 61

Wall thickening. Maximum wall thickness ≥ 3 mm (without irregularity of the mucosal surface and layered structure). Category 3, Assessment D2

Fig. 62

Wall thickening. Irregular layered structure (with irregularity of the mucosal surface and layered structure). Category 5, Assessment D1

Fig. 63

Protruded or mass lesion (polyp). Mass lesion (without disruption of the layered structure of the attached wall). Category 4, Assessment D2

Fig. 64

Protruded or mass lesion (polyp). Mass lesion (with disruption of the layered structure of the attached wall). Category 5, Assessment D1

Fig. 65

Other findings. Stone image (with acoustic shadow). Category 2, Assessment D1

Fig. 66

Other findings. Stone image (without acoustic shadow). Category 2, Assessment D1

Fig. 67

Other findings. Debris echo (with dilated extrahepatic bile duct). Category 3, Assessment D2

Table 6 Pancreas

Fig. 68

Measurement of main pancreatic duct diameter

Fig. 69

Morphological abnormality. Maximum short diameter < 10 mm. Category 2, Assessment D2

Fig. 70

Morphological abnormality. Maximum short diameter ≥ 30 mm. Category 2, Assessment D2

Fig. 71

Morphological abnormality. Localized swelling (pancreatic head) (with decreased echo level). Category 4, Assessment D2

Fig. 72

Morphological abnormality. Localized swelling (pancreatic tail) (with decreased echo level). Category 4, Assessment D2

Fig. 73

Main pancreatic duct dilatation. Maximum diameter ≥ 3 mm at pancreatic body (with calcification of pancreatic parenchyma). Category 3, Assessment D2

Fig. 74

Main pancreatic duct dilatation. Maximum diameter ≥ 3 mm at pancreatic body (with calcification in the main pancreatic duct). Category 3, Assessment D2

Fig. 75

Main pancreatic duct dilatation. Maximum diameter ≥ 3 mm at pancreatic body (with papillary nodule in the main pancreatic duct). Category 4, Assessment D2

Fig. 76

Main pancreatic duct dilatation. Maximum diameter ≥ 3 mm at pancreatic body (with downstream (duodenal side) stenosis). Left: pancreatic body; right: main pancreatic duct stenosis in the pancreatic head. Category 4, Assessment D2

Fig. 77

Solid lesion. Hypo(iso)echoic or mixed hyper- and hypoechoic mass lesion (lesion presenting a mixed pattern with a mixture of solid and cystic components). Category 4, Assessment D2

Fig. 78

Cystic lesion. A solid component (mural nodules/wall thickening) is present (lesion presenting a mixed pattern with a mixture of solid and cystic components). Category 4, Assessment D2

Fig. 79

Solid lesion. Hyperechoic mass lesion (maximum diameter < 15 mm). Category 2, Assessment C

Fig. 80

Solid lesion. Hyperechoic mass lesion (maximum diameter ≥ 15 mm). Category 3, Assessment D2

Fig. 81

Solid lesion. Hypoechoic mass lesion. Category 4, Assessment D2

Fig. 82

Solid lesion. Hypoechoic mass lesion (with eggshell-like calcification). Category 4, Assessment D2

Fig. 83

Solid lesion. Hypoechoic mass lesion with the disrupted main pancreatic duct (mass lesion with dilatation of caudal pancreatic duct). Category 5, Assessment D1

Fig. 84

Cystic lesion (including branch dilatation). Maximum diameter ≥ 5 mm. Category 3, Assessment D2

Fig. 85

Cystic lesion (including branch dilatation). A solid component (mural nodules) is present. Category 4, Assessment D2

Fig. 86

Cystic lesion (including branch dilatation). A solid component (wall thickening) is present. Category 4, Assessment D2

Fig. 87

Cystic lesion (including branch dilatation). A change in internal fluid (internal echogenic spots) is present. Category 4, Assessment D2

Fig. 88

Cystic lesion (including branch dilatation). A change in internal fluid (internal echogenic spots) is present. Category 4, Assessment D2

Fig. 89

Other findings. Calcified lesion (calcification in the pancreatic body and tail). Category 2, Assessment C

Fig. 90

Other findings. Calcification lesion (calcification in the main pancreatic duct in the pancreatic head (without main pancreatic duct dilatation in the pancreatic body)). Category 2, Assessment C

Fig. 91

Other findings. Vascular abnormality (A cystic lesion is observed in the pancreas body by the B-mode, and an internal blood flow signal is present on color Doppler.). Left: B-mode; right: color Doppler. Category 2, Assessment D2

Table 7 Spleen

Fig. 92

Measurement of spleen diameter. Visualize the spleen in the long-axis view and measure the maximum diameter

Fig. 93

Post-local treatment (post-splenic embolization). Category 2, Assessment C

Fig. 94

Malformation. Maximum diameter ≥ 15 cm. Category 3, Assessment D2

Fig. 95

Solid lesion. Hyperechoic mass image. Category 3, Assessment D2

Fig. 96

Solid lesion. Hypoechoic mass image. Category 4, Assessment D2

Fig. 97

Solid lesion. Hyper/hypoechoic mixed mass image. Category 4, Assessment D2

Fig. 98

Solid lesion. Central hyperechoic mass image. Category 5, Assessment D1

Fig. 99

Cystic lesion. A solid component (intracystic nodules/wall thickening/internal echogenic spots) is present. Category 4, Assessment D2

Fig. 100

Other findings. Calcified opacity. Category 2, Assessment B

Fig. 101

Other findings. Vascular abnormality (collateral flow of splenic vein). Category 2, Assessment D2

Fig. 102

Other findings. Solid lesion in the splenic hilum. Category 3, Assessment D2

Fig. 103

Other findings. Solid lesion in the splenic hilum (image of oval mass with homogeneous internal echo at echo level equal to that of the spleen). Category 2, Assessment B

Table 8 Kidneys

Fig. 104

Measurement of kidney diameter. Measure the longest diameter where the renal parenchyma would normally be, without including cyst protruding outside the kidney

Fig. 105

Post-partial resection/post-renal transplantation. Post-partial resection. Category 2, Assessment B

Fig. 106

Post-partial resection/post-renal transplantation. Transplanted kidney (post-transplantation in pelvic cavity). Category 2, Assessment B

Fig. 107

Morphological abnormality. Congenital deformity (renal column of Bertin). Category 2, Assessment B

Fig. 108

Morphological abnormality. Congenital deformity (double renal pelvis). Category 2, Assessment B

Fig. 109

Morphological abnormality. Congenital deformity (horseshoe kidney). Right abdominal vertical scan, abdominal midline horizontal scan, and left abdominal vertical scan. Category 2, Assessment B

Fig. 110

Morphological abnormality. Rugged contour is present (basket-like blood flow is displayed in lesion on color Doppler). Left: convex probe; right: power Doppler with high-frequency probe. Category 3, Assessment D2

Fig. 111

Morphological abnormality. A rugged contour is present (vascular structure similar to that of the normal renal parenchyma on color Doppler). Left: renal long-axis view; right: color Doppler. Category 2, Assessment B

Fig. 112

Morphological abnormality. Splitting and deformation of central echo complex. Category 3, Assessment D2

Fig. 113

Solid lesion. Hyperechoic mass with maximum diameter < 10 mm. Left: convex probe; right: high-frequency linear probe. Category 3, Assessment C

Fig. 114

Solid lesion. A solid lesion is present (hypoechoic mass with irregular contour). Category 3, Assessment D2

Fig. 115

Solid lesion. A peripheral hypoechoic zone is present in a round lesion with a distinct border and smooth contour. Category 4, Assessment D2

Fig. 116

Solid lesion. Deformation of the central echo complex is present (hypoechoic lesion with irregular contour). Category 4, Assessment D2

Fig. 117

Solid lesion. An internal anechoic region with a peripheral hypoechoic zone and lateral shadow is present in a round lesion with a distinct border and a smooth contour. Category 5, Assessment D1

Fig. 118

Solid lesion. Brightness equal to or higher than that of the central echo complex with an irregular contour. Maximum diameter < 40 mm. Category 2, Assessment C

Fig. 119

Solid lesion. Brightness equal to or higher than that of the central echo complex a comet image is present. Maximum diameter < 40 mm. Category 2, Assessment C

Fig. 120

Solid lesion. Brightness equal to or higher than that of the central echo complex with an irregular contour and comet image is present. Maximum diameter ≥ 40 mm. Category 2, Assessment D2

Fig. 121

Cystic lesion. No more than two thin septi are present. Category 2, Assessment B

Fig. 122

Cystic lesion. Microcalcification is present. Category 2, Assessment B

Fig. 123

Cystic lesion. Five or more cysts are present bilaterally (longest diameter > 9 cm on both sides). Left: right renal long-axis view; right: left renal long-axis view. Category 2, Assessment D2

Fig. 124

Cystic lesion. Five or more cysts are present bilaterally (longest diameter ≤ 9 cm). Left: right renal long-axis view, right: left renal long-axis view. Category 2, Assessment C

Fig. 125

Cystic lesion. Multiple thin septi are present. Category 3, Assessment C

Fig. 126

Cystic lesion. Multiple thin septi and nodular calcification are present. Left: convex probe; right: high-frequency probe. Category 3, Assessment C

Fig. 127

Cystic lesion. A solid component (septal thickening) is present. Category 4, Assessment D2

Fig. 128

Cystic lesion. A solid component (intracystic nodules) is present. Category 4, Assessment D2

Fig. 129

Other findings. Calcified lesion (in renal parenchyma). Category 2, Assessment B

Fig. 130

Other findings. Calcified lesion (in renal parenchyma/in pelviocaliceal system). Renal stone. Maximum diameter ≥ 10 mm. Category 2, Assessment D2

Fig. 131

Other findings. Calcified lesion. In the pelviocaliceal system. Maximum diameter < 10 mm. Left: long-axis view; right: short-axis view. Category 2, Assessment C

Fig. 132

Other findings. Calcified lesion. In the pelviocaliceal system. Maximum diameter ≥ 10 mm. Category 2, Assessment D2

Fig. 133

Other findings. Pyelectasis (unknown cause of occlusion). Category 3, Assessment D2

Fig. 134

Other findings. Mild pyelectasis (without caliectasis). Category 2, Assessment B

Fig. 135

Other findings. Pyelectasis (with calcified lesion in the occluded region). Category 2, Assessment D2

Fig. 136

Other findings. Pyelectasis (with calcified lesion in the ureter). Category 2, Assessment D2

Fig. 137

Other findings. Pyelectasis (with a solid lesion in the occluded region). Left: renal long-axis view; right: long-axis view of upper ureter from renal pelvis. Category 4, Assessment D2

Fig. 138

Other findings. Vascular abnormality. A cystic lesion is present in the renal hilus (left), and a blood flow signal is present on color Doppler (right). Left: renal short-axis view b-mode; right: color Doppler. Category 2, Assessment D2

Fig. 139

Other findings. Vascular abnormality. An irregular anechoic lesion is present in the renal central echo complex (left), and a blood flow signal is present on color Doppler (right). Left: renal long-axis view b-mode; right: color Doppler. Category 2, Assessment D2

Table 9 Abdominal aorta

Fig. 140

Measurement of fusiform aneurysm diameter. (https://www.jsum.or.jp/committee/diagnostic/pdf/aorticlesion2020.pdf)

Fig. 141

Post-treatment (stent-graft insertion). Category 2, Assessment B

Fig. 142

Localized aortic dilatation (32 mm). Fusiform dilatation. Maximum short diameter ≥ 30 mm, < 45 mm. Left: short-axis view; right: long-axis view. Category 2, Assessment C

Fig. 143

Localized aortic dilatation (62 mm). Fusiform dilatation. Maximum short diameter ≥ 55 mm. Left: Short-axis view; right: long-axis view. Category 2, Assessment D1P

Fig. 144

Localized aortic dilatation. Saccular dilatation (saccular aneurysm). Left: short-axis view; right: long-axis view. Category 2, Assessment D2P

Fig. 145

Other findings. A flap is present (maximum short diameter 23 mm). Category 2, Assessment D2

Fig. 146

Other findings. Plaque. Category 2, Assessment C

Fig. 147

Other findings. Wall thickening and calcification. Category 2, Assessment C

Table 10 Others

Fig. 148

Lymph-node swelling. Minor axis ≥ 7 mm. Category 3, Assessment C

Fig. 149

Lymph-node swelling. Either minor axis ≥ 10 mm or minor/major axis ratio ≥ 0.5. Category 4, Assessment D2

Fig. 150

Intraperitoneal fluid retention. Left: right upper abdominal horizontal scan; right: right lower abdominal horizontal scan. Category 3, Assessment D2

Fig. 151

Intraperitoneal fluid retention (with debris echo). Category 4, Assessment D2

Fig. 152

Intrathoracic fluid retention (without debris echo in pleural fluid). Category 3, Assessment D2

Fig. 153

Intrathoracic fluid retention (with debris echo in pleural fluid). Category 4, Assessment D2

Fig. 154

Intrathoracic fluid retention (with solid echo image in pleural fluid). Category 4, Assessment D2

Fig. 155

Fluid retention in cardiac cavity. Category 2, Assessment D2

Fig. 156

Abdominal cavity, retroperitoneum, or pelvic cavity (including adrenal gland). Retroperitoneal mass image. Category 3, Assessment D2

Fig. 157

Abdominal cavity, retroperitoneum, or pelvic cavity (including adrenal gland). Intravesical mass image. Category 3, Assessment D2