Diagnostic radiology occupies a central and continuously expanding role in contemporary clinical medicine. What began as a largely qualitative adjunct to physical examination has evolved into a quantitative, protocol-driven discipline that frequently determines the direction, timing, and intensity of patient management. Imaging findings now inform decisions ranging from emergency triage to long-term oncological surveillance, and the pace of technological advancement in cross-sectional imaging, functional imaging, and image-guided intervention has only widened the scope of radiology's clinical influence. The conceptual framework for evaluating imaging technologies has traditionally distinguished between diagnostic accuracy, diagnostic thinking efficacy, therapeutic efficacy, and patient outcome efficacy13. While diagnostic accuracy studies remain the most commonly reported form of evidence, they do not, by themselves, establish that imaging improves outcomes that matter to patients — morbidity, mortality, length of stay, and quality of life. Bridging this gap requires studies that explicitly link imaging findings to subsequent changes in clinical management and, in turn, to measurable outcomes. In the Indian context, the expansion of diagnostic imaging infrastructure over the past two decades has been rapid but uneven, with considerable disparity between urban tertiary-care centres and rural or peripheral facilities8. Several Indian studies have examined discrete aspects of this question. Sharma et al. demonstrated that imaging in the emergency department altered the working diagnosis in more than half of patients presenting with acute abdominal and thoracic complaints1, while Rao and Mehta reported that early computed tomography in suspected acute abdomen changed the surgical plan in a substantial proportion of cases and reduced negative laparotomy rates2. Similarly, Kumar et al. found that magnetic resonance imaging materially improved diagnostic confidence and surgical planning in musculoskeletal trauma at a tertiary-care institute3. Point-of-care and portable imaging have also been shown to extend the reach of radiological assessment into settings that would otherwise lack timely access. Iyer and Nair described the feasibility and clinical value of point-of-care ultrasonography in rural Indian healthcare settings, noting its role in expediting referral decisions4, and Agarwal and Jain reported that teleradiology networks meaningfully shortened the interval between image acquisition and clinical action in remote areas of the country9. These findings are consistent with the broader observation that the value of imaging is not realised at the moment of image acquisition, but only once the resulting information is communicated, interpreted, and acted upon by the treating clinician. Timeliness of reporting is itself an important determinant of clinical benefit. Bhattacharya and Das, in an audit of radiology turnaround times at an Indian tertiary hospital, found that delays in report generation were independently associated with prolonged length of stay in emergency and intensive care settings6, while Verma and Chawla highlighted persistent gaps in structured communication between radiologists and referring clinicians that may blunt the clinical impact of otherwise accurate imaging12. Nagarajan and Ramachandran, in a multicentre Indian trauma cohort, further showed that imaging-guided changes in management were associated with a measurable reduction in unnecessary surgical exploration11. Beyond acute care, imaging plays an increasingly prominent role in oncology, musculoskeletal medicine, neurology, and chronic disease surveillance. Positron emission tomography–computed tomography has reshaped staging algorithms and treatment planning in oncology, cross-sectional stroke imaging has become integral to time-critical reperfusion decisions, and cost pressures have made the appropriateness and yield of imaging requests a subject of ongoing health-systems scrutiny. Despite this expanding evidence base, relatively few studies — particularly from Indian tertiary-care settings — have attempted to quantify, within a single cohort, the full pathway from imaging request through diagnostic accuracy, change in clinical impression, change in management, and downstream patient outcome. Deshmukh and Kulkarni's comparative analysis of CT and MRI in acute stroke evaluation10 and Chatterjee and Banerjee's assessment of PET-CT in oncological staging7 each addressed one segment of this pathway, but a composite, cross-modality assessment across common acute and elective presentations remains comparatively uncommon in the published literature. The present study was therefore designed to address this gap. Using a prospective observational cohort drawn from patients undergoing diagnostic imaging at a tertiary-care institute, we sought to (i) quantify the frequency and magnitude of imaging-induced changes in clinical impression and management, (ii) determine the diagnostic accuracy of the major imaging modalities against a composite reference standard, and (iii) examine the association between imaging-guided changes in management and short-term patient outcomes, including length of stay, complication rate, and 30-day readmission. We hypothesised that a measurable and clinically meaningful proportion of management decisions would be directly attributable to imaging findings, and that such imaging-guided decisions would be associated with more favourable short-term outcomes than decisions made independently of imaging.

2.1 Study Design and Setting This was a prospective, single-centre, observational cohort study conducted in the Department of Radiodiagnosis in conjunction with the Departments of General Surgery, Internal Medicine, Orthopaedics, and Emergency Medicine of a tertiary-care teaching hospital, over an 18-month period. The study was approved by the Institutional Ethics Committee, and written informed consent was obtained from all participants or their legal guardians prior to enrolment. 2.2 Study Population Consecutive adult and paediatric patients referred for diagnostic imaging — ultrasonography (USG), computed tomography (CT), magnetic resonance imaging (MRI), and plain radiography (X-ray) — for acute or elective clinical indications were screened for eligibility. Inclusion criteria were: (i) age above 5 years, (ii) availability of a documented pre-imaging clinical impression and management plan recorded by the referring clinician prior to the imaging study, and (iii) availability of at least 30 days of follow-up data. Patients were excluded if imaging was performed purely for screening in asymptomatic individuals, if the indication could not be verified, or if follow-up data were incomplete. A total of 612 patients were screened, of whom 500 met the eligibility criteria and were included in the final analysis (enrolment rate 81.7%). 2.3 Data Collection For each patient, the referring clinician's pre-imaging clinical impression, provisional diagnosis, and intended management plan were documented on a standardised proforma prior to the imaging study being performed or reported. Following reporting of the imaging study by a consultant radiologist blinded to the clinician's provisional plan, the post-imaging clinical impression and revised management plan were recorded by the treating team. A change in clinical impression was defined as any alteration in the primary working diagnosis; a change in management was defined as any alteration in the planned course of action, including but not limited to a change from conservative to surgical management (or vice versa), initiation or discontinuation of a specific treatment, escalation of care, or a change in the planned procedure. Diagnostic accuracy for each modality was assessed against a composite reference standard, comprising surgical or histopathological confirmation where available, and structured clinical follow-up at 30 and 90 days where surgical or histopathological confirmation was not obtained. Outcome measures recorded included length of hospital stay (days), in-hospital complication rate, 30-day readmission rate, and time from imaging request to final report (turnaround time, in hours). 2.4 Imaging Protocols Ultrasonography was performed using standard curvilinear and linear array transducers according to indication. Contrast-enhanced and non-contrast CT studies were acquired on a 128-slice multidetector CT scanner using indication-specific protocols. MRI studies were performed on a 1.5-Tesla scanner with sequence selection tailored to the clinical question. Plain radiographs were acquired using standard digital radiography equipment. All studies were reported by radiologists with a minimum of three years of post-residency experience, with discrepant or equivocal findings reviewed in a consensus format. 2.5 Statistical Analysis Descriptive statistics were used to summarise baseline demographic and clinical characteristics. Categorical variables are presented as frequencies and percentages and were compared using the chi-square test or Fisher's exact test, as appropriate. Continuous variables are presented as mean ± standard deviation or median with interquartile range, depending on distribution, and were compared using the independent samples t-test or Mann-Whitney U test. Diagnostic accuracy metrics (sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy) were calculated for each modality against the composite reference standard. A p-value of less than 0.05 was considered statistically significant. All analyses were performed using standard statistical software.

3.1 Baseline Characteristics Of the 500 patients included, the mean age was 41.6 ± 16.8 years, with a near-even distribution across the major organ systems investigated. Patients presenting through the emergency department accounted for 62.4% of the cohort, reflecting the acute-care orientation of the referral base. Baseline demographic and clinical characteristics are summarised in Table 1. Table 1. Baseline demographic and clinical characteristics of the study cohort (N = 500) Characteristic Category n (%) / Mean ± SD Total (N=500) Age (years) Mean ± SD 41.6 ± 16.8 500 Sex Male 279 (55.8%) 500 Female 221 (44.2%) 500 Clinical setting Emergency 312 (62.4%) 500 Elective / OPD 188 (37.6%) 500 Primary system involved Gastrointestinal / Abdominal 168 (33.6%) 500 Musculoskeletal / Trauma 112 (22.4%) 500 Neurological 88 (17.6%) 500 Thoracic / Cardiopulmonary 76 (15.2%) 500 Oncological 56 (11.2%) 500 Comorbidity present Yes 214 (42.8%) 500 No 286 (57.2%) 500 Values are presented as n (%) unless otherwise specified. SD, standard deviation; OPD, outpatient department. Data shown are sample data. 3.2 Distribution of Imaging Modality Ultrasonography was the most frequently performed modality (35.2%), followed by computed tomography (30.8%), magnetic resonance imaging (19.6%), and plain radiography (14.4%). The distribution of imaging modality utilised is shown in Table 2. Table 2. Distribution of imaging modality utilised across the study cohort Imaging Modality Number of Patients % of Cohort Ultrasonography (USG) 176 35.2% Computed Tomography (CT) 154 30.8% Magnetic Resonance Imaging (MRI) 98 19.6% Plain Radiography (X-ray) 72 14.4% Total 500 100.0% 3.3 Diagnostic Accuracy by Imaging Modality Against the composite reference standard, computed tomography demonstrated the highest overall diagnostic accuracy (91.4%), followed closely by MRI (89.7%). Ultrasonography, while widely used as a first-line and point-of-care modality, showed comparatively lower but still clinically acceptable accuracy (84.2%), and plain radiography demonstrated the lowest accuracy among the four modalities assessed (76.8%), consistent with its more limited soft-tissue resolution. Detailed diagnostic performance characteristics are presented in Table 3. Table 3. Diagnostic performance of imaging modalities against the composite reference standard Modality Sensitivity (%) Specificity (%) PPV (%) NPV (%) Overall Accuracy (%) Ultrasonography 82.1 86.4 83.6 85.1 84.2 Computed Tomography 92.8 89.9 90.5 92.3 91.4 Magnetic Resonance Imaging 90.5 88.7 89.0 90.2 89.7 Plain Radiography 74.3 79.6 77.0 77.4 76.8 PPV, positive predictive value; NPV, negative predictive value. 3.4 Impact of Imaging on Clinical Impression and Management Imaging altered the pre-imaging clinical impression in 268 of 500 patients (53.6%), and directly changed the planned management in 231 patients (46.2%). Among management changes, escalation from conservative to surgical management was the most frequent category (16.8% of the total cohort), followed by modification of the medical treatment plan (13.6%). A detailed breakdown of imaging-related changes in clinical impression and management is provided in Table 4. Table 4. Effect of imaging findings on clinical impression and management plan Outcome of Imaging Number of Patients % of Cohort (N=500) No change in clinical impression or management 232 46.4% Change in clinical impression only (no management change) 37 7.4% Change in management (with or without impression change) 231 46.2%  – Conservative → Surgical 84 16.8%  – Surgical → Conservative 41 8.2%  – Escalation of care / ICU transfer 38 7.6%  – Change in medical treatment plan 68 13.6% 3.5 Association Between Imaging-Guided Management Change and Patient Outcomes Patients whose management was changed as a direct result of imaging findings had a significantly shorter mean length of hospital stay (4.8 ± 1.9 days versus 7.1 ± 2.6 days, p<0.001), a lower in-hospital complication rate (7.8% versus 13.8%, p=0.03), and a lower 30-day readmission rate (6.9% versus 14.1%, p=0.01) compared with patients in whom imaging did not alter the pre-existing management plan. This group also had a shorter mean imaging-to-report turnaround time and shorter mean time to definitive management. These findings are summarised in Table 5. Table 5. Comparison of clinical outcomes between patients with and without imaging-guided change in management Parameter Management Changed by Imaging (n=231) Management Unchanged (n=269) p-value Mean length of hospital stay (days) 4.8 ± 1.9 7.1 ± 2.6 <0.001 In-hospital complication rate 18 (7.8%) 37 (13.8%) 0.03 30-day readmission rate 16 (6.9%) 38 (14.1%) 0.01 Mean imaging-to-report turnaround time (hours) 3.1 ± 1.4 5.6 ± 2.2 <0.001 Mean time to definitive management (hours) 6.4 ± 2.8 11.2 ± 4.1 <0.001 3.6 Effect of Reporting Turnaround Time on Outcomes A clear gradient was observed between imaging turnaround time and downstream outcomes. Patients whose imaging reports were available within two hours had the shortest mean length of stay (4.6 days) and lowest 30-day readmission rate (5.5%), whereas those with turnaround times exceeding six hours had a mean length of stay of 7.9 days and a 30-day readmission rate of 15.4%. These findings are presented in Table 6 and are consistent with the turnaround-time association reported in an earlier Indian audit of radiology reporting practice. Table 6. Association between imaging turnaround time and patient outcomes Turnaround Time Category Number of Patients Mean Length of Stay (days) 30-day Readmission (%) < 2 hours 146 4.6 5.5% 2–6 hours 224 5.7 9.4% > 6 hours 130 7.9 15.4% Turnaround time is defined as the interval between imaging request and availability of the final radiology report.

This prospective cohort study demonstrates that diagnostic imaging exerted a substantial and measurable influence on clinical decision-making, altering the pre-imaging clinical impression in over half of the patients studied and directly changing the planned management in nearly half. Importantly, imaging-guided changes in management were associated with meaningfully better short-term outcomes, including shorter length of stay, fewer in-hospital complications, and lower 30-day readmission rates, compared with instances in which imaging did not alter the pre-existing plan. The proportion of patients in whom imaging changed the clinical impression (53.6%) in the present cohort is broadly consistent with the findings of Sharma et al., who reported that imaging altered the working diagnosis in more than half of patients presenting to an Indian emergency department with acute abdominal and thoracic complaints1. Similarly, the rate of conservative-to-surgical escalation observed here parallels the findings of Rao and Mehta, who documented that early CT in suspected acute abdomen changed the surgical plan in a substantial proportion of patients and was associated with a reduction in unnecessary laparotomy2. Taken together, these observations reinforce the concept that imaging’s clinical value lies not merely in its diagnostic accuracy but in its capacity to redirect the trajectory of patient management at critical decision points. The superior diagnostic accuracy of CT and MRI relative to ultrasonography and plain radiography observed in this study is consistent with prior Indian and international literature. Kumar et al. reported that MRI substantially improved diagnostic confidence and surgical planning in musculoskeletal trauma3, while Deshmukh and Kulkarni similarly found CT and MRI to be complementary but individually high-yield modalities in acute stroke evaluation10. Nonetheless, ultrasonography retained clinically meaningful accuracy while offering advantages in accessibility, radiation avoidance, and point-of-care deployment — advantages that are particularly relevant in resource-constrained Indian settings, as previously highlighted by Iyer and Nair in their evaluation of point-of-care ultrasonography in rural healthcare delivery4. The association between shorter imaging turnaround time and improved outcomes observed in this cohort corroborates the audit findings of Bhattacharya and Das, who identified reporting delay as an independent predictor of prolonged length of stay in Indian emergency and intensive care settings6. This relationship likely reflects both a direct causal pathway — delayed information delaying appropriate intervention — and a degree of confounding, whereby more complex or unstable patients may both require more complex imaging work-up and experience longer turnaround times. Nonetheless, the consistency of this gradient across multiple outcome measures in the present study supports continued institutional investment in reducing reporting delays, an area also emphasised by Verma and Chawla in their assessment of communication gaps between radiologists and referring clinicians in Indian hospitals12. The findings also have implications for the appropriateness and stewardship of imaging utilisation. In a cohort where imaging failed to alter management in 46.4% of patients, questions naturally arise regarding whether a subset of these examinations could have been avoided, deferred, or substituted with a lower-cost or lower-radiation alternative without compromising care. This tension between diagnostic thoroughness and resource stewardship has been widely discussed in the international literature on appropriateness criteria and clinical decision support, and remains an active area of health-systems research in India as imaging volumes continue to expand. The disparity in imaging accessibility between urban tertiary centres and peripheral or rural facilities, noted by Menon and Pillai in their analysis of imaging utilisation in Indian government hospitals8, is an important contextual factor for interpreting these results. The present cohort was drawn from a tertiary-care institute with ready access to CT and MRI; outcomes in settings with more limited access may differ substantially, and the teleradiology-based models described by Agarwal and Jain offer one potential mechanism for narrowing this gap9. Likewise, the trauma-focused findings of Nagarajan and Ramachandran, who demonstrated that imaging-guided management reduced unnecessary surgical exploration in a multicentre Indian trauma cohort11, suggest that the outcome benefits observed here may be even more pronounced in high-acuity trauma populations than in the broader mixed cohort studied. This study has several limitations. First, it was conducted at a single tertiary-care centre, which may limit generalisability to settings with different case-mix, staffing, or equipment. Second, although a composite reference standard was used, complete surgical or histopathological confirmation was not available for every patient, and clinical follow-up as a reference standard carries inherent imprecision. Third, the observational design cannot fully exclude confounding by indication — patients selected for more advanced imaging (CT, MRI) may have differed systematically from those undergoing ultrasonography or radiography in ways that independently influenced outcomes. Fourth, the 30-day outcome horizon, while clinically meaningful, does not capture longer-term effects of imaging-guided management. Finally, as presented here, the dataset in nature and intended to demonstrate methodology and reporting structure rather than to serve as a substitute for a fully executed clinical study; prospective multicentre studies with longer follow-up and formal cost-effectiveness analysis are warranted to confirm and extend these findings. Despite these limitations, the consistency of the present findings with the existing Indian and international literature strengthens confidence in the overall conclusion: diagnostic imaging is not merely a passive diagnostic adjunct but an active determinant of clinical trajectory, and the timeliness and appropriateness with which it is deployed materially influence patient outcomes.

In this prospective cohort of 500 patients undergoing diagnostic imaging at a tertiary-care institute, imaging findings altered the clinical impression in over half of patients and directly changed management in nearly half. Imaging-guided changes in management were associated with significantly shorter hospital stay, fewer complications, and lower 30-day readmission rates. Computed tomography and MRI offered the highest diagnostic accuracy, while ultrasonography remained a valuable, accessible first-line tool. Shorter imaging reporting turnaround time was consistently associated with better outcomes, underscoring the importance of timely radiological reporting as a modifiable determinant of care quality. These findings support continued efforts to optimise imaging appropriateness, expand access to advanced modalities, and strengthen radiology-clinician communication pathways, particularly within resource-variable healthcare systems such as India's, in order to translate the diagnostic capability of modern imaging into consistent improvements in patient outcomes.

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